Conjugates containing phosphorus(V) and camptothecin moieties

Abstract

The present invention relates to a conjugate having formula (I), in which a receptor binding molecule (RBM) is linked to a camptothecin moiety (C). The present invention also relates to intermediates for producing same, processes for preparing same, pharmaceutical compositions containing same, and uses thereof. TIFF2024540692000507.tif35128

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority from European Patent Application No. 21207284.7, filed November 9, 2021, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] Technical Field The present invention relates to conjugates of receptor-binding molecules and camptothecin moieties, intermediates for producing same, methods for preparing same, pharmaceutical compositions containing same, and uses thereof. [Background technology]

[0003] background Antibody-drug conjugates (ADCs) are biotherapeutics that combine cytotoxic molecules with the targeting properties of antibodies to specifically kill cancer cells. One class of drugs being explored for use in ADCs is camptothecin and its derivatives. Camptothecin and its derivatives have attracted considerable interest because they act as inhibitors of topoisomerase I. Exemplary ADCs of camptothecin and its derivatives are described, for example, in Han et al., "The Potential of Topoisomerase Inhibitor-Based Antibody-Drug Conjugates," Pharmaceutics 2022, 14, 1701, https: / / doi.org / 10.3390 / pharmaceutics14081707 (Non-Patent Document 1); Conilh et al., "Exatecan Antibody Drug Conjugates Based on a Hydrophilic Polysarcosine Drug-Linker Platform," Pharmaceuticals 2021, 14, 247, https: / / doi.org / 10.3390 / ph14030247 (Non-Patent Document 2); WO 2020 / 245229 (Patent Document 1); WO 2019 / 236954 (Patent Document 2); Burke et al., "Design, Synthesis, and Biological Evaluation of Antibody-Drug Conjugates" and Viricel et al., "Monodisperse polysarcosine-based highly-loaded antibody-drug conjugates", Chemical Science, 2019, 10, 4048-4053, doi: 10.1039 / c9sc00285e.

[0004] One camptothecin-derived ADC that has attracted much attention is the ADC of the anti-Her2 antibody trastuzumab and deruxtecan. This ADC has been approved for medical use and is also known as DS-8201a and sold under the trade name Enhertu. This ADC has been described by Ogitani et al., "DS-8201a, A Novel HER2-Targeting ADC with a Novel DNA Topoisomerase I Inhibitor, Demonstrates a Promising Antitumor Efficacy with Differentiation from T-DM1," Clinical Cancer Research (22)20, October 15, 2016, pp. 5097-5108 (DOI: 10.1158 / 1078-0432.CCR-15-2822) (Non-Patent Document 5).

[0005] Enhertu was initially approved for the treatment of solid tumors, namely, Her2+ breast cancer and colorectal cancer. More recently, Enhertu has been shown to shift the paradigm for targeted therapy of Her2-positive breast cancer, as it has shown very promising results even in patients with low levels of Her2 expression, who were previously considered ineligible for targeted Her2 therapy (see, for example, Siddiqui et al., "Enhertu (Fam-trastuzumab-deruxtecan-nxki) - Revolutionizing treatment paradigm for HER2-Low breast cancer", Annals of Medicine and Surgery 82 (2022) 104665; https: / / doi.org.10.1016 / j.amsu.2022.104665). Although Enhertu is an approved and commercially available ADC, certain drawbacks remain. In particular, Enhertu has been found to exhibit relatively poor serum stability. Furthermore, non-target-related toxicity of Enhertu remains a commonly observed problem in therapeutic applications. Many of the reasons for this may be related to shortcomings of the linker system between the payload and the antibody (Mckertish et al., “Advances and Limitations of Antibody Drug Conjugates for Cancer,” Biomedicines 2021, 9, 872; https: / / doi.org / 10.3390 / biomedicines9080872). For example, uptake of the ADC into non-target cells due to membrane interactions with the hydrophobic linker-payload structure, or the formation of aggregates in the form of higher molecular weight species caused by the hydrophobicity of the payload, are likely to cause non-target-related toxicity in patients. Furthermore, premature release of the payload from the ADC and its transfer to serum proteins can further lead to off-target side effects. This combination of effects can lead to life-threatening side effects, such as interstitial lung disease and a decrease in white blood cells, especially neutrophils, both of which are the most common serious side effects described for Enhertu.

[0006] Thus, there remains a need for additional conjugates that include a camptothecin moiety as a drug, particularly conjugates that exhibit improved serum stability or other improvements over Enherz. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO 2020 / 245229 [Patent Document 2] WO 2019 / 236954 [Non-patent literature]

[0008] [Non-Patent Document 1] Han et al., “The Potential of Topoisomerase Inhibitor-Based Antibody-Drug Conjugates”, Pharmaceutics 2022, 14, 1701, https: / / doi.org / 10.3390 / pharmaceutics14081707 [Non-patent document 2] Conilh et al., “Exatecan Antibody Drug Conjugates Based on a Hydrophilic Polysarcosine Drug-Linker Platform”, Pharmaceuticals 2021, 14, 247, https: / / doi.org / 10.3390 / ph14030247 [Non-patent document 3] Burke et al., “Design, Synthesis, and Biological Evaluation of Antibody-Drug Conjugates Comprised of Potent Camptothecin Analogs”, Bioconjugate Chem. 2009, 20, 1242-1250, doi: 10.1021 / bc9001097 [Non-Patent Document 4] Viricel et al., “Monodisperse polysarcosine-based highly-loaded antibody-drug conjugates”, Chemical Science, 2019, 10, 4048-4053, doi: 10.1039 / c9sc00285e) [Non-Patent Document 5] Ogitani et al., “DS-8201a, A Novel HER2-Targeting ADC with a Novel DNA Topoisomerase I Inhibitor, Demonstrates a Promising Antitumor Efficacy with Differentiation from T-DM1”, Clinical Cancer Research (22)20, October 15, 2016, pp. 5097-5108 (DOI: 10.1158 / 1078-0432.CCR-15-2822) [Non-Patent Document 6] Siddiqui et al., “Enhertu (Fam-trastuzumab-deruxtecan-nxki) - Revolutionizing treatment paradigm for HER2-Low breast cancer”, Annals of Medicine and Surgery 82 (2022) 104665; https: / / doi.org.10.1016 / j.amsu.2022.104665 [Non-Patent Document 7] Mckertish et al., “Advances and Limitations of Antibody Drug Conjugates for Cancer”, Biomedicines 2021, 9, 872; https: / / doi.org / 10.3390 / biomedicines9080872 Summary of the Invention

[0009] overview This need is addressed by the subject matter as defined in the claims and in the embodiments described herein.

[0010] Thus, the present invention provides a conjugate having formula (I): TIFF2024540692000002.tif35128, or a pharmaceutically acceptable salt or solvate thereof; During the ceremony: RBM is a receptor binding molecule; TIFF2024540692000003.tif6128 is a double bond; or TIFF2024540692000004.tif6128 is a single bond; V is absent if TIFF2024540692000005.tif6128 is a double bond; or V is TIFF2024540692000006.tif6128 is a single bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000007.tif6128 is a double bond, then R3-C; or X is If TIFF2024540692000008.tif6128 is a single bond, TIFF2024540692000009.tif9128; Y is NR 5 , S, O, or CR 6 R 7and; R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20.

[0011] The present invention also provides a compound having formula (II): TIFF2024540692000010.tif27128, or a pharmaceutically acceptable salt or solvate thereof; During the ceremony: TIFF2024540692000011.tif6128 is a triple bond; or TIFF2024540692000012.tif6128 is a double bond; V is absent if TIFF2024540692000013.tif6128 is a triple bond; or V is TIFF2024540692000014.tif6128 is a double bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000015.tif6128 is a triple bond, then R3-C: or X is If TIFF2024540692000016.tif6128 is a double bond, TIFF2024540692000017.tif9128; Y is NR 5 , S, O, or CR 6 R 7 and; R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10.

[0012] The present invention also relates to a method for preparing a conjugate of formula (I), said method comprising: Compounds of formula (II): TIFF2024540692000018.tif27128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: TIFF2024540692000019.tif6128 is a triple bond; or TIFF2024540692000020.tif6128 is a double bond; V is absent if TIFF2024540692000021.tif6128 is a triple bond; or V is TIFF2024540692000022.tif6128 is a double bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000023.tif6128 is a triple bond, then R3-C: or X is If TIFF2024540692000024.tif6128 is a double bond, TIFF2024540692000025.tif9128; Y is NR 5 , S, O, or CR 6 R 7 and; R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10; a compound of formula (II) or a pharmaceutically acceptable salt or solvate thereof; Thiol-containing molecules of formula (III): TIFF2024540692000026.tif9128, wherein RBM is a receptor binding molecule; and n is an integer ranging from 1 to 20; a thiol-containing molecule of formula (III) By reacting Compounds of formula (I): TIFF2024540692000027.tif36128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: TIFF2024540692000028.tif6128 is a compound of formula (II) TIFF2024540692000029.tif6128 is a triple bond, then it is a double bond; or TIFF2024540692000030.tif6128 is a compound of formula (II) TIFF2024540692000031.tif6128 is a double bond, while it is a single bond; V is absent if TIFF2024540692000032.tif6128 is a double bond; or V is TIFF2024540692000033.tif6128 is a single bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000034.tif6128 is a double bond, then R3-C; or X is If TIFF2024540692000035.tif6128 is a single bond, TIFF2024540692000036.tif9128; Y is NR 5 , S, O, or CR 6 R7 and; R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20; A compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof The method includes the step of generating

[0013] The present invention also relates to a conjugate of formula (I) obtainable or obtainable by the method of the present invention.

[0014] The present invention also relates to pharmaceutical compositions comprising the conjugates of the present invention.

[0015] The present invention also relates to a conjugate of the present invention for use in a method of treating a disease. The disease may be cancer. The cancer may be a solid tumor.

[0016] The present invention also relates to a pharmaceutical composition of the present invention for use in a method of treating a disease. The disease may be cancer. The cancer may be a solid tumor. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows an analytical HPLC chromatogram of the compound methyl 4-azido-2-(dodecaethyleneglycol)benzoate. The horizontal axis depicts retention time in minutes. [Figure 2] 1 shows an analytical HPLC chromatogram of the compound methyl 4-azido-2-(dodecaethyleneglycol)benzoate. The horizontal axis depicts retention time in minutes. [Figure 3] 1 shows an analytical HPLC chromatogram of compound P5(PEG12)-COOH. [Figure 4] 1 shows an analytical HPLC chromatogram of compound P5(PEG24)-OSu. The horizontal axis depicts retention time in minutes. [Figure 5] 1 shows an analytical HPLC chromatogram of compound P5(PEG12,PEG24)-COOH. The horizontal axis depicts retention time in minutes. [Figure 6] 1 shows an analytical HPLC chromatogram of compound P5(PEG24,PEG24)-COOH. The horizontal axis depicts retention time in minutes. [Figure 7] 1 shows an analytical HPLC chromatogram of the compound NH2-VC-PAB-exatecan TFA salt. [Figure 8] 1 shows an analytical HPLC chromatogram of the compound NH2-VC-PAB-exatecan TFA salt. [Figure 9] 1 shows an analytical HPLC chromatogram of isomer A of the compound NH2-VA-exatecan. [Figure 10] 1 shows an analytical HPLC chromatogram of isomer B of the compound NH2-VA-exatecan. [Figure 11] 1 shows an analytical HPLC chromatogram of compound P5 (PEG2)-VC-PAB-exatecan. [Figure 12]1 shows an analytical HPLC chromatogram of compound P5 (PEG12)-VC-PAB-exatecan. [Figure 13] 1 shows an analytical HPLC chromatogram of compound P5 (PEG24)-VC-PAB-exatecan. [Figure 14] 1 shows an analytical HPLC chromatogram of compound P5 (PEG12)-VA-PAB-exatecan. [Figure 15] 1 shows an analytical HPLC chromatogram of compound P5(PEG12)-VA-exatecan from Isomer A. [Figure 16] 1 shows an analytical HPLC chromatogram of compound P5(PEG12)-VA-exatecan from isomer B. [Figure 17] 1 shows an analytical HPLC chromatogram of compound P5(PEG12)-exatecan. [Figure 18] Figure 1 shows an analytical SEC chromatogram of trastuzumab, where SEC stands for size exclusion chromatography. [Figure 19] 1 shows an analytical HIC chromatogram of trastuzumab, where HIC stands for hydrophobic interaction chromatography. [Figure 20] 1 shows an analytical SEC chromatogram of brentuximab. [Figure 21] 1 shows an analytical HIC chromatogram of brentuximab. [Figure 22] 1 shows an analytical SEC chromatogram of palivizumab. [Figure 23] 1 shows an analytical HIC chromatogram of palivizumab. [Figure 24] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG12)-VC-PAB-exatecan. [Figure 25] 1 shows analytical HIC chromatograms of trastuzumab-P5(PEG12)-VC-PAB-exatecan. [Figure 26] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG24)-VC-PAB-exatecan. [Figure 27]1 shows analytical HIC chromatograms of trastuzumab-P5(PEG24)-VC-PAB-exatecan. [Figure 28] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG12)-VA-PAB-exatecan. [Figure 29] 1 shows analytical HIC chromatograms of trastuzumab-P5(PEG12)-VA-PAB-exatecan. [Figure 30] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG12)-VA-PAB-exatecan. [Figure 31] 1 shows analytical HIC chromatograms of trastuzumab-P5(PEG12)-VA-PAB-exatecan. [Figure 32] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG12)-VA-exatecan (isomer A). [Figure 33] 1 shows an analytical HIC chromatogram of trastuzumab-P5(PEG12)-VA-exatecan (isomer A). [Figure 34] 1 shows an analytical SEC chromatogram of trastuzumab-P5(PEG12)-VA-exatecan (isomer B). [Figure 35] 1 shows an analytical HIC chromatogram of trastuzumab-P5(PEG12)-VA-exatecan (isomer B). [Figure 36] 1 shows an analytical SEC chromatogram of brentuximab-P5(PEG12)-VC-PAB-exatecan. [Figure 37] 1 shows analytical HIC chromatograms of brentuximab-P5(PEG12)-VC-PAB-exatecan. [Figure 38] 1 shows an analytical SEC chromatogram of brentuximab-P5(PEG24)-VC-PAB-exatecan. [Figure 39] 1 shows analytical HIC chromatograms of brentuximab-P5(PEG24)-VC-PAB-exatecan. [Figure 40]1 shows an analytical SEC chromatogram of Palivizumab-P5(PEG24)-VC-PAB-exatecan. [Figure 41] 1 shows analytical HIC chromatograms of palivizumab-P5(PEG24)-VC-PAB-exatecan. [Figure 42-1] Figure 1 shows MS spectra of glycosylated reduced trastuzumab after reaction with different equivalents of TCEP (top) and 15 equivalents of linker-payload (P5(PEG24)-VC-PAB-exatecan). The calculation of DAR from these spectra, depending on the amount of TCEP, is shown in the graph below. [Figure 42-2] See description of Figure 42-1. [Figure 42-3] See description of Figure 42-1. [Figure 43] In vitro cytoxicity of trastuzumab (anti-Her2) ADCs linked to different exatecan-based linker-payload constructs in antigen-positive cell lines (HCC-78, top, and SKBR3, bottom left) and antigen-negative cell lines (MDA-MB-468, bottom right). [Figure 44] Figure 1 shows the in vitro cytotoxicity of trastuzumab (anti-Her2) ADC (trastuzumab-P5(PEG24)-VC-PAB-exatecan) and a non-binding isotype control (palivizumab-P5(PEG24)-VC-PAB-exatecan) in an antigen-positive cell line (HCC-78). [Figure 45] Shows the in vitro cytotoxicity of brentuximab (anti-CD30) ADC (brentuximab-P5(PEG12)-VC-PAB-exatecan) in two antigen-positive cell lines (L-540, left, and SU-DHL-1, right). [Figure 46] Figure 1 shows the in vitro cytotoxicity of brentuximab (anti-CD30) ADC (brentuximab-P5(PEG24)-VC-PAB-exatecan) in a panel of antigen-positive cell lines (SR-786, SU-DHL-1, HH, HBLM-2, L-540, MOTN-1) and a non-targeting control cell line (HL-60). [Figure 47]Evaluation of the bystander effect of trastuzumab-P5(PEG24)-VC-PAB-exatecan in a head-to-head comparison with Enhertz. In vitro cytotoxicity of the ADC in an antigen-positive cell line (SKBR3, top left) and an antigen-negative cell line (MDA-MB-468, top right). To assess bystander killing, supernatants from SKBR-3 incubated with the ADC were transferred to MDA-MB-468 (MDA-MB-468, bottom). [Figure 48] Relative quantification of histone H2A.X phosphorylation (top left), activated caspase 3 (top right), and activated PARP (bottom left) and cell viability (bottom right) after treatment of SKBR-3 cells with trastuzumab-P5(PEG24)-VC-PAB-exatecan, Enhertu, unconjugated exatecan, or unconjugated camptothecin after 1, 2, or 3 days versus untreated is shown. [Figure 49] The drug-antibody ratios of Enhertz and P5(PEG24)-VC-PAB-exatecan are shown after incubation in rat serum for 0, 1, 3, and 7 days at 37° C. Drug-antibody ratios were measured by MS after pulldown of the ADC from serum. [Figure 50] Cytotoxicity of the ADCs trastuzumab-P5(PEG12)-VC-PAB-exatecan (top), trastuzumab-P5(PEG24)-VC-PAB-exatecan (middle), and Enhertu (bottom) measured on the Her2-negative cell line MDA-MB-468 (left) and the Her2-positive cell line SKBR3 (right) after incubation with rat serum at 37°C for 0, 1, 3, and 7 days. [Figure 51] Cytotoxicity of the ADCs trastuzumab-P5(PEG12)-VC-PAB-exatecan (top), trastuzumab-P5(PEG24)-VC-PAB-exatecan (middle), and Enhertu (bottom) measured on the Her2-negative cell line MDA-MB-468 (left) and the Her2-positive cell line SKBR3 (right) after incubation with human serum at 37°C for 0, 1, 3, and 7 days. [Figure 52]1 shows quantification of total antibody levels in the circulation after treatment of female Sprague-Dawley rats with brentuximab-P5(PEG12)-VC-PAB-exatecan-DAR8 by ELISA. [Figure 53] 1 shows the melting curves of trastuzumab-P5(PEG24)-VC-PAB-exatecan and Enhertu determined using nanodifferential scanning fluorescence (nanoDSF). [Figure 54] Graphs for determining the equilibrium binding constants (KD) for Enhertu and trastuzumab-P5(PEG24)-VC-PAB-exatecan binding to extracellular Her2 are shown, as well as the resulting values ​​for the equilibrium binding constants (KD). [Figure 55] 1 shows the percentage of aggregates formed after 0, 1, 2, and 4 weeks when the ADCs trastuzumab-P5(PEG24)-VC-PAB-exatecan with a drug-antibody ratio of 8 (denoted "DAR8") and Enhertz were incubated in the dark at 37°C and 4°C. [Figure 56] Figure 1 shows percent specific killing measured in a calcein release-based antibody-dependent cytotoxicity (ADCC) assay using Her2-positive target cells SKBR-3, SKOV-3, and N87 with unconjugated trastuzumab, trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8, Enherz, and an isotype control. [Figure 57] 1 shows the results of a pHrodo-based study of internalization using unconjugated trastuzumab, trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 and Enhertu with Her2-positive SKOV-3 cells and Her2-negative MDA-MB-468 cells. [Figure 58]

[0033] Figure 1 shows the results of in vitro cytotoxicity assays performed using trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 and Enhertz with Her2-positive cells SKBR-3, N87, HCC-1569, HCC-78, OE-19, SK-GT-2, and SKOV-3. [Figure 59] Figure 1 shows the results of in vitro bystander potential measured after incubation of Her2-positive SKBR3 cells with trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 and Enhertz, and supernatant transfer to Her2-negative cells Karpas-299 and DU-145. [Figure 60] 1 shows the results of measuring the in vitro bystander potential of trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 and Enhertu in a co-culture of Her2-positive SKBR-3 cells and Her2-negative MDA-MB-468 cells. [Figure 61]

[0039] Figure 1 shows the results of cytotoxicity assays performed using trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8, Enhertz, and palivizumab-P5(PEG24)-VC-PAB-exatecan DAR8 against human umbilical vein endothelial cells, human bronchial endothelial cells, hepatic sinusoidal endothelial cells, Schwann cells, human renal proximal tubule epithelial cells, normal human skin fibroblasts, human corneal epithelial cells, and THLE-3 (hepatocytes). The cytotoxicity of trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 is shown compared to palivizumab-P5(PEG24)-VC-PAB-exatecan DAR8 and Enhertz. [Figure 62] 1 shows the results of an in vivo pharmacokinetic experiment performed with trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 in female SCID mice treated with 20 mg / kg trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 or Enhertu as reference. [Figure 63] 1 shows the mean tumor volume of CB17-Scid mice determined in a solid tumor model after treatment with H8-P5(PEG24)-VC-PAB-exatecan DAR8. [Figure 64] Figure 1 shows the body weight of CB17-Scid mice after treatment with H8-P5(PEG24)-VC-PAB-exatecan DAR8. [Figure 65]1 shows the results of an in vivo pharmacokinetic study (PK study) obtained in female SD rats treated with 10 mg / kg of H8-P5(PEG24)-VC-PAB-exatecan DAR8 or unmodified H8 antibody. [Figure 66] 1 shows HIC and SEC chromatograms of trastuzumab P5(PEG24)-VC-PAB-exatecan DAR4 with an average DAR4. [Figure 67] 1 shows the results of an in vivo pharmacokinetic study (PK study) obtained in female SD rats treated with trastuzumab-P5(PEG24)-VC-PAB-exatecan 10 mg / kg with a mean DAR4. [Figure 68]

[0033] Figure 1 shows the results of an in vivo evaluation of trastuzumab-P5(PEG24)-VC-PAB-exatecan DAR8 with a drug-antibody ratio of 8 (DAR8) in a head-to-head comparison with Enhertz. Initial results are reported after several days of tumor growth observation. DETAILED DESCRIPTION OF THE INVENTION

[0018] Detailed Description The present invention is described in detail below and is further illustrated by the accompanying examples and figures.

[0019] definition Unless otherwise indicated, the term "alkyl," by itself or as part of another term, generally refers to a substituted or unsubstituted straight- or branched-chain saturated hydrocarbon having the indicated number of carbon atoms; for example, "-(C1-C8)alkyl" or "-(C1-C 10") alkyl" refers to an alkyl group having 1 to 8 or 1 to 10 carbon atoms, respectively. If the number of carbon atoms is not specified, the alkyl group can have 1 to 8 carbon atoms. Representative straight-chain -(C1-C8) alkyl groups include, but are not limited to, -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, -n-hexyl, -n-heptyl, and -n-octyl; branched-chain -(C1-C8) alkyl groups include, but are not limited to, -isopropyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl, and -2-methylbutyl. In some aspects, an alkyl group can be unsubstituted. Optionally, an alkyl group can be substituted, for example, with one or more groups.

[0020] Unless otherwise indicated, the term "alkylene" by itself or as part of another term generally refers to an alkylene group having the indicated number of carbon atoms, preferably 1 to 10 carbon atoms (-(C-C 10 (-C1-C8)alkylene-) or preferably 1 to 8 carbon atoms (-(C1-C8)alkylene-), and having two monovalent radical centers derived by removing two hydrogen atoms from the same or two different carbon atoms of a parent alkane. When the number of carbon atoms is not indicated, the alkylene group can have 1 to 8 carbon atoms. Typical alkylene radicals include, but are not limited to, methylene (-CH2-), 1,2-ethylene (-CH2CH2-), 1,3-n-propylene (-CH2CH2CH2-), and 1,4-n-butylene (-CH2CH2CH2CH2-). In some embodiments, the alkylene group can be unsubstituted. Optionally, the alkylene group can be substituted, for example with one or more groups.

[0021] Unless otherwise indicated, the term "alkenyl," by itself or as part of another term, generally refers to a substituted or unsubstituted straight or branched chain unsaturated hydrocarbon having a double bond and the indicated number of carbon atoms; for example, "-(C2-C8)alkenyl" or "-(C2-C10 "-(C2-C8)alkenyl" refers to an alkenyl group having 2 to 8 or 2 to 10 carbon atoms, respectively. If the number of carbon atoms is not specified, the alkenyl group can have 2 to 8 carbon atoms. Representative -(C2-C8)alkenyl groups include, but are not limited to, -ethenyl, -1-propenyl, -2-propenyl, -1-butenyl, -2-butenyl, -isobutenyl, -1-pentenyl, -2-pentenyl, -3-methyl-1-butenyl, -2-methyl-2-butenyl, and -2,3-dimethyl-2-butenyl. In some aspects, an alkenyl group can be unsubstituted. Optionally, an alkenyl group can be substituted, for example, with one or more groups.

[0022] Unless otherwise indicated, the term "alkenylene," by itself or as part of another term, generally refers to an alkenylene having the indicated number of carbon atoms, preferably 2 to 10 carbon atoms (-(C-C 10 (C2-C8)alkenylene-) or preferably 2 to 8 carbon atoms (-(C2-C8)alkenylene-), and having a double bond and two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkene, refers to a substituted or unsubstituted unsaturated branched or straight-chain hydrocarbon radical. If the number of carbon atoms is not indicated, the alkenylene group can have 1 to 8 carbon atoms. Typical alkenylene radicals include, but are not limited to, -ethenylene-, -1-propenylene-, 2-propenylene-, -1-butenylene-, -2-butenylene-, -isobutenylene-, -1-pentenylene-, -2-pentenylene-, -3-methyl-1-butenylene-, -2-methyl-2-butenylene-, and -2,3-dimethyl-2-butenylene-. In some aspects, the alkenylene group can be unsubstituted. Alkenylene groups can be optionally substituted, for example with one or more groups.

[0023] Unless otherwise indicated, the term "alkynyl," by itself or as part of another term, generally refers to a substituted or unsubstituted straight or branched chain unsaturated hydrocarbon having a triple bond and the indicated number of carbon atoms; for example, "-(C2-C8)alkynyl" or "-(C2-C 10 "-(C2-C8)alkynyl" refers to an alkynyl group having 2 to 8 or 2 to 10 carbon atoms, respectively. If the number of carbon atoms is not specified, the alkynyl group can have 2 to 8 carbon atoms. Representative -(C2-C8)alkynyl groups include, but are not limited to, -acetylenyl, -1-propynyl, -2-propynyl, -1-butynyl, -2-butynyl, -1-pentynyl, -2-pentynyl, and -3-methyl-1-butynyl. In some aspects, an alkynyl group can be unsubstituted. Optionally, an alkynyl group can be substituted, for example, with one or more groups.

[0024] Unless otherwise indicated, the term "alkynylene," by itself or as part of another term, generally refers to an alkynylene having the indicated number of carbon atoms, preferably 2 to 10 carbon atoms (-(C-C 10 (C2-C8)alkynylene-) or preferably 2 to 8 carbon atoms (-(C2-C8)alkynylene-), and having a triple bond and two monovalent radical centers derived by removing two hydrogen atoms from the same or two different carbon atoms of a parent alkyne. When the number of carbon atoms is not indicated, the alkynylene group can have 2 to 8 carbon atoms. Typical alkynylene radicals include, but are not limited to, -ethynylene-, -1-propynylene-, -2-propynylene-, -1-butynylene-, -2-butynylene-, -1-pentynylene-, -2-pentynylene-, and -3-methyl-1-butynylene-. In some aspects, the alkynylene group can be unsubstituted. Optionally, the alkynylene group can be substituted, for example with one or more groups.

[0025] Unless otherwise indicated, the term "aryl," by itself or as part of another term, generally refers to a substituted or unsubstituted monovalent carbocyclic aromatic hydrocarbon radical of 6 to 20 carbon atoms (preferably 6 to 14 carbon atoms, more preferably 6 to 10 carbon atoms, and in a highly preferred embodiment, 6 carbon atoms) derived by removing one hydrogen atom from a single carbon atom of a parent aromatic ring system. Some aryl groups are represented in the exemplary structures as "Ar." Typical aryl groups include, but are not limited to, radicals derived from benzene, substituted benzene, naphthalene, anthracene, and biphenyl. An exemplary aryl group is the phenyl group. In some aspects, an aryl group can be unsubstituted. Optionally, an aryl group can be substituted, for example, with one or more groups.

[0026] Unless otherwise indicated, the term "arylene," by itself or as part of another term, generally refers to an aryl group in which one of the hydrogen atoms has been replaced with a bond (i.e., it is divalent), with phenyl as an exemplary group, having the following structure: As shown in TIFF2024540692000037.tif22128, the aryl group may be para-, meta-, or ortho-oriented, as defined above. In selected embodiments, for example, when the parallel connector unit comprises an arylene, the arylene is an aryl group as defined above, in which two or more of the aryl group's hydrogen atoms are replaced with bonds (i.e., the arylene may be trivalent). In some aspects, the arylene group may be unsubstituted. Optionally, the alkynylene group may be substituted, for example, with one or more groups.

[0027] Unless otherwise indicated, the term "heterocycle" or "heterocyclic ring," by itself or as part of another term, generally refers to a heterocycle having the indicated number of carbon atoms (e.g., "(C3-C8)heterocycle" or "(C3-C 10)Heterocycle" refers to a monovalent substituted or unsubstituted aromatic or non-aromatic monocyclic or bicyclic ring system having a heterocycle having 3 to 8 or 3 to 10 carbon atoms, respectively) and one to four heteroatom ring members independently selected from N, O, P, or S, and derived by the removal of a hydrogen atom from a ring atom of the parent ring system. One or more N, C, or S atoms in a heterocycle can be oxidized. The ring containing the heteroatom can be aromatic or non-aromatic. Unless otherwise specified, a heterocycle is attached to its pendant group at any heteroatom or carbon atom that results in a stable structure. Representative examples of (C3-C8) heterocycle include, but are not limited to, pyrrolidinyl, azetidinyl, piperidinyl, morpholinyl, tetrahydrofuranyl, tetrahydropyranyl, benzofuranyl, benzothiophene, indolyl, benzopyrazolyl, pyrrolyl, thiophenyl (thiophene), furanyl, thiazolyl, imidazolyl, pyrazolyl, pyrimidinyl, pyridinyl, pyrazinyl, pyridazinyl, isothiazolyl and isoxazolyl.In some aspects, heterocyclic group can be unsubstituted.Optionally, heterocyclic group can be substituted, for example, with one or more groups.

[0028] Unless otherwise indicated, the terms "heterocyclo" or "heterocyclic ring," by themselves or as part of another term, generally refer to a heterocyclic group, as defined above, and having the indicated number of carbon atoms (e.g., (C-C)heterocycle or (C-C) 10 ) heterocycle). In selected embodiments, for example, when the parallel connector unit includes a heterocycle, the heterocycle is a heterocyclic group as defined above, in which two or more of the heterocyclic group's hydrogen atoms are replaced with bonds (i.e., the heterocycle can be trivalent). In some aspects, the heterocyclo or heterocyclic ring can be unsubstituted. Optionally, the heterocyclo or heterocyclic ring can be substituted, for example, with one or more groups.

[0029] Unless otherwise indicated, the term "carbocycle" or "carbocyclic ring", by itself or as part of another term, generally refers to a ring system having the indicated number of carbon atoms derived by removing one hydrogen atom from a ring atom of the parent ring system (e.g., "(C3-C8)carbocycle" or "(C3-C 10 ")Carbocycle" refers to a monovalent substituted or unsubstituted aromatic or non-aromatic monocyclic or bicyclic carbocyclic ring system having (referring to a carbocycle having 3 to 8 or 3 to 10 carbon atoms, respectively). As an illustrative, but non-limiting example, a carbocycle can be a 3-, 4-, 5-, 6-, 7-, or 8-membered carbocycle. Representative (C3-C8)carbocycles include, but are not limited to, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentadienyl, cyclohexyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptyl, 1,3-cycloheptadienyl, 1,3,5-cycloheptatrienyl, cyclooctyl, and cyclooctadienyl. In some aspects, a carbocycle can be unsubstituted. Optionally, a carbocycle can be substituted, e.g., with one or more groups.

[0030] Unless otherwise indicated, the term "carbocyclo" or "carbocyclic ring," by itself or as part of another term, generally refers to a carbocyclic ring having the indicated number of carbon atoms (e.g., "(C3-C8)carbocyclo" or "(C3-C8)carbocyclo"), in which another hydrogen atom of the carbocyclic ring has been replaced with a bond (i.e., it is divalent). 10 ")Carbocyclo" refers to a carbocyclic group as defined above having 3 to 8 or 3 to 10 carbon atoms, respectively. In selected embodiments, for example, when a parallel connector unit comprises a carbocyclo or carbocyclic ring, the carbocyclo or carbocyclic ring is a carbocyclic group as defined above in which two or more of the carbocyclic group's hydrogen atoms are replaced with bonds (i.e., the carbocyclo or carbocyclic ring can be trivalent). In some aspects, the carbocyclo or carbocyclic ring can be unsubstituted. Optionally, the heterocyclo or heterocyclic ring can be substituted, for example, with one or more groups.

[0031] Unless otherwise indicated, the term "heteroalkyl," by itself or in combination with another term, means, unless otherwise stated, an alkyl group having the indicated number of carbon atoms (e.g., (C-C)heteroalkyl or (C-C 10 (Heteroalkyl) may mean a stable straight- or branched-chain hydrocarbon, fully saturated or containing 1 to 3 degrees of unsaturation, or combinations thereof, consisting of 1 to 10, preferably 1 to 3, heteroatoms selected from the group consisting of O, N, Si, and S, where the nitrogen and sulfur atoms are optionally oxidized and the nitrogen heteroatom is optionally quaternized. The O, N, and S heteroatoms may be placed at any interior position of the heteroalkyl group or at the position at which the alkyl group is attached to the remainder of the molecule. The Si heteroatom may be placed at any position of the heteroalkyl group, including the position at which the alkyl group is attached to the remainder of the molecule. Examples include -CH2-CH2-O-CH3, -CH2-CH2-NH-CH3, -CH2-CH2-N(CH3)-CH3, -CH2-S-CH2-CH3, -CH2-CH2-S(O)-CH3, -NH-CH2-CH2-NH-C(O)-CH2-CH3, -CH2-CH2-S(O)-CH3, -CH=CH-O-CH3, -Si(CH3)3, -CH2-CH=NO-CH3, and -CH=CH-N(CH3)-CH3. Up to two heteroatoms may be consecutive, such as, for example, -CH2-NH-OCH3 and -CH2-O-Si(CH3)3. In preferred embodiments, the (C1-C4) heteroalkyl or heteroalkylene has 1 to 4 carbon atoms and 1 or 2 heteroatoms, and the (C1-C3) heteroalkyl or heteroalkylene has 1 to 3 carbon atoms and 1 or 2 heteroatoms. In some aspects, the heteroalkyl or heteroalkylene is saturated. In some aspects, the heteroalkyl or heteroalkylene can be unsubstituted. Optionally, the heteroalkyl or heteroalkylene can be substituted, for example, with one or more groups.

[0032] Unless otherwise stated, the term “heteroalkylene,” by itself or as part of another substituent, refers to any heteroalkyl group having the indicated number of carbon atoms (e.g., (C-C)heteroalkylene or (C-C), as exemplified by —CH—CH—S—CH—CH— and —CH—S—CH—CH—NH—CH—). 10 ) heteroalkylene). For heteroalkylene groups, heteroatoms can also occupy either or both of the chain termini. Furthermore, for alkylene and heteroalkylene linking groups, no orientation of the linking group is implied. In selected embodiments, for example, when the parallel connector unit comprises a heteroalkylene, the heteroalkylene is a heteroalkyl group as defined above in which two or more of the heteroalkyl group's hydrogen atoms are replaced with bonds (i.e., the heteroalkylene can be trivalent). In some aspects, the heteroalkyl or heteroalkylene can be saturated. In some aspects, the heteroalkylene is unsubstituted. Optionally, the heteroalkylene can be substituted, for example, with one or more groups.

[0033] The term "halogen", unless otherwise defined, generally refers to elements of main group 7; preferably fluorine, chlorine, bromine and iodine; more preferably fluorine, chlorine and bromine; even more preferably fluorine and chlorine.

[0034] The terms "substituted," "optionally substituted," "optionally substituted," and the like, unless otherwise indicated, generally mean that one or more hydrogen atoms can each be independently replaced by a substituent. Exemplary substituents include -X, -R, -O, and the like. - , -OR, -SR, -S - , -NR2, -NR3, =NR, -CX3, -CN, -OCN, -SCN, -N=C=O, -NCS, -NO, -NO2, =N2, -N3, -NRC(=O)R, -C(=O)R, -C(=O)NR2, -SO3 -, -SO3H, -S(=O)2R, -OS(=O)2OR, -S(=O)2NR, -S(=O)R, -OP(=O)(OR)2, -P(=O)(OR)2, -PO4 3- , -PO3H2, -C(=O)R, -C(=O)X, -C(=S)R, -COR, -COH, -C(=S)OR, -C(=O)SR, -C(=S)SR, -C(=O)NR2, -C(=S)NR2, or -C(=NR)NR2, where each X is independently a halogen: -F, -CI, -Br, or -I; and each R is independently -H, -(C1-C 20 ) alkyl (e.g., -(C1-C 10 ) alkyl or -(C1-C8) alkyl), -(C6-C 20 ) aryl (e.g., -(C6-C 10 ) aryl or, preferably, -C6-aryl), -(C3-C 14 ) heterocycles (e.g., -(C3-C 10 )heterocycle or -(C3-C8)heterocycle), a protecting group, or a prodrug moiety. Typical substituents also include (=O).

[0035] The term "aliphatic or aromatic residue," as used herein, generally refers to an aliphatic substituent, such as, but not limited to, an alkyl residue, which may, however, be substituted by further aliphatic and / or aromatic substituents. As a non-limiting example, an aliphatic residue may have a direct linkage (R 1In the case of (e.g., the linkage to the oxygen atom attached to phosphorus) is aliphatic, the aromatic residue may be a nucleic acid, an enzyme, a coenzyme, a nucleotide, an oligonucleotide, a monosaccharide, a polysaccharide, a polymer, a fluorophore, an optionally substituted benzene, etc. An aromatic residue is a substituent where the direct linkage to the core structure is an aromatic system, e.g., an optionally substituted phenyl or triazolyl or pyridyl, or part of a nucleotide; non-limiting examples include when the direct linkage of a nucleotide to the core structure is via, for example, a phenyl residue. The term "aromatic residue" as used herein also includes heteroaromatic residues.

[0036] The term "peptide," unless otherwise indicated, generally refers to an organic compound containing two or more amino acids covalently joined by peptide bonds (amide bonds). Peptides may be referred to in terms of the number of constituent amino acids, i.e., a dipeptide contains two amino acid residues, a tripeptide contains three, etc. Peptides containing 10 or fewer amino acids are called oligopeptides, while those having 10 or more amino acid residues, e.g., up to about 30 amino acid residues, are polypeptides.

[0037] The term "amino acid" as used herein generally refers to an organic compound having a -CH(NH3)-COOH group. In one embodiment, the term "amino acid" refers to naturally occurring amino acids. Illustrative examples of naturally occurring amino acids include arginine, lysine, aspartic acid, glutamic acid, glutamine, asparagine, histidine, serine, threonine, tyrosine, cysteine, methionine, tryptophan, alanine, isoleucine, leucine, phenylalanine, valine, proline and glycine. However, in a broader sense, this term also includes non-naturally occurring amino acids.

[0038] Amino acids and peptides according to the present disclosure can also be modified at functional groups, non-limiting examples being sugars, such as N-acetylgalactosamine (GalNAc), or protecting groups, such as fluorenylmethoxycarbonyl (Fmoc) modifications or esters.

[0039] The term "antibody," as used herein, is preferably intended to refer to an immunoglobulin molecule composed of four polypeptide chains, two heavy (H) chains and two light (L) chains, typically interconnected by disulfide bonds. Each heavy chain is composed of a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region. The heavy chain constant region can contain, for example, three domains: CH1, CH2, and CH3. Each light chain is composed of a light chain variable region (abbreviated herein as VL) and a light chain constant region. The light chain constant region is composed of one domain (CL). The VH and VL regions can be further subdivided into regions of hypervariability called complementarity-determining regions (CDRs), interspersed with more conserved regions called framework regions (FRs). Each VH and VL is typically composed of three CDRs and up to four FRs, arranged from amino terminus to carboxy terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4, for example.

[0040] As used herein, the term "complementarity-determining region" (CDR; e.g., CDR1, CDR2, and CDR3) refers to the amino acid residues of an antibody variable domain whose presence is necessary for antigen binding. Each variable domain typically has three CDR regions, identified as CDR1, CDR2, and CDR3. Each complementarity determining region may comprise amino acid residues from a "complementarity determining region" as defined by Kabat (e.g., about residues 24-34 (L1), 50-56 (L2), and 89-97 (L3) in the light chain variable domain and 31-35 (H1), 50-65 (H2), and 95-102 (H3) in the heavy chain variable domain); and / or residues from a "hypervariable loop" (e.g., about residues 26-32 (L1), 50-52 (L2), and 91-96 (L3) in the light chain variable domain and 26-32 (H1), 53-55 (H2), and 96-101 (H3) in the heavy chain variable domain). In some cases, a complementarity determining region may comprise amino acids from both a CDR region and a hypervariable loop as defined according to Kabat.

[0041] Depending on the amino acid sequence of the constant domain of their heavy chains, intact antibodies can be assigned to different "classes." There are five major classes of intact antibodies: IgA, IgD, IgE, IgG, and IgM, and some of these can be further divided into "subclasses" (isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2. The preferred class of immunoglobulin for use in the present invention is IgG.

[0042] The heavy chain constant domains corresponding to different classes of antibodies are called "alpha," "delta," "epsilon," "gamma," and "mu," respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known. As used herein, "antibody" refers to conventionally known antibodies and functional fragments thereof.

[0043] A "functional fragment," or "antigen-binding antibody fragment" of an antibody / immunoglobulin, or "antigen-binding fragment of an antibody," or "antibody fragment," or "fragment of an antibody," generally refers to a fragment of an antibody / immunoglobulin (e.g., the variable region of an IgG) that retains the antigen-binding region. The "antigen-binding region" of an antibody is typically found in one or more hypervariable regions of the antibody, e.g., the CDR1, -2, and / or -3 regions; however, variable "framework" regions can also play an important role in antigen binding, such as by providing a scaffold for the CDRs. Preferably, the "antigen-binding region" comprises at least amino acid residues 4-103 of the variable light (VL) chain and 5-109 of the variable heavy (VH) chain, more preferably amino acid residues 3-107 of the VL and 4-111 of the VH, with the complete VL and VH chains (amino acid positions 1-109 of the VL and 1-113 of the VH; numbering according to WO 97 / 08320).

[0044] "Functional fragments," "antigen-binding antibody fragments," "antigen-binding fragments of antibodies," or "antibody fragments" or "antibody fragments" of the present disclosure may include, but are not limited to, those containing at least one disulfide bond capable of reacting with a reducing agent as described herein. Examples of suitable fragments include Fab, Fab', Fab'-SH, F(ab')2, and Fv fragments; diabodies; single-domain antibodies (DAbs), linear antibodies; single-chain antibody molecules (scFv); and multispecific antibodies such as bispecific and trispecific antibodies formed from antibody fragments. An antibody other than a "multispecific" or "multifunctional" antibody is understood to have each of its binding sites identical. F(ab')2 or Fab may be engineered to minimize or completely eliminate intermolecular disulfide interactions that occur between the CH1 and CL domains.

[0045] The term "Fc region" herein is generally used to define the C-terminal region of an immunoglobulin heavy chain that contains at least a portion of the constant region. This term includes native sequence Fc regions and variant Fc regions. In one embodiment, a human IgG heavy chain Fc region extends from Cys226 or Pro230 to the carboxyl terminus of the heavy chain. However, the C-terminal lysine (Lys447) of the Fc region may or may not be present. Unless otherwise specified herein, the numbering of amino acid residues in the Fc region or constant region is according to the EU numbering system, also known as the EU index.

[0046] A variant of an antibody or antigen-binding antibody fragment contemplated herein is a molecule that retains the binding activity of the antibody or antigen-binding antibody fragment.

[0047] "Binding proteins" or "proteinaceous binding molecules with antibody-like binding properties" as used herein are generally known to those skilled in the art. Illustrative, non-limiting examples include affibodies, adnectins, anticalins, DARPins, and avimers.

[0048] A "human" antibody or antigen-binding fragment thereof is generally defined as one that is not chimeric (e.g., not "humanized") and not derived (in whole or in part) from a non-human species. A human antibody or antigen-binding fragment thereof may be of human origin or may be a synthetic human antibody. A "synthetic human antibody" is defined herein as an antibody having a sequence derived in silico, in whole or in part, from a synthetic sequence based on analysis of known human antibody sequences. In silico design of a human antibody sequence or fragment thereof can be achieved, for example, by analyzing a database of human antibody or antibody fragment sequences and devising a polypeptide sequence using the data obtained therefrom. Another example of a human antibody or antigen-binding fragment thereof is one encoded by a nucleic acid isolated from a library of antibody sequences of human origin (e.g., such a library is based on antibodies taken from natural human sources).

[0049] A "humanized antibody" or humanized antigen-binding fragment thereof is generally defined herein as (i) an antibody derived from a non-human source (e.g., a transgenic mouse with a heterologous immune system) based on human germline sequences; (ii) an antibody in which amino acids in the framework regions of a non-human antibody have been partially replaced with human amino acid sequences by genetic engineering; or (iii) a CDR-grafted antibody in which the CDRs of the variable domain are derived from a non-human source, but one or more frameworks of the variable domain are of human origin, and the constant domains, if present, are of human origin.

[0050] A "chimeric antibody" or antigen-binding fragment thereof is generally defined herein as one in which the variable domains are derived from non-human origin and some or all of the constant domains are derived from human origin.

[0051] The term "monoclonal antibody," as used herein, generally refers to an antibody obtained from a population of substantially homogeneous antibodies; i.e., the individual antibodies comprising the population are identical except for possible minor mutations, e.g., naturally occurring mutations. Thus, the term "monoclonal" indicates the character of the antibody as not being a mixture of individual antibodies. In contrast to polyclonal antibody preparations, which typically contain different antibodies directed against different determinants (epitopes), each monoclonal antibody of a monoclonal antibody preparation is directed against a single determinant on an antigen. In addition to their specificity, monoclonal antibody preparations are advantageous in that they are typically uncontaminated by other immunoglobulins. The term "monoclonal" should not be construed as requiring production of the antibody by any particular method. The term monoclonal antibody specifically includes chimeric, humanized, and human antibodies.

[0052] An "isolated" antibody is generally one that has been identified and separated from components of the cell in which it is expressed. The contaminating components of the cell are substances that would interfere with diagnostic or therapeutic uses for the antibody, and may include enzymes, hormones, and other proteinaceous or non-proteinaceous solutes.

[0053] As used herein, an antibody "specifically binds to," "is specific for," or "specifically recognizes" an antigen of interest, e.g., a tumor-associated polypeptide antigen target, and generally binds the antigen with sufficient affinity so that the antibody is useful as a therapeutic when targeted to cells or tissues expressing the antigen, and does not significantly cross-react with other proteins or proteins other than orthologs and variants (e.g., mutant forms, splice variants, or proteolytically truncated forms) of said antigen target. As used herein, the terms "specifically recognize" or "specifically binds to" or "is specific for" a particular polypeptide or epitope on a particular polypeptide target, as used herein, refer to, for example, an antibody that "specifically binds to," "is specific for," or "is specific for," an antibody that "specifically recognizes" an antigen of interest, e.g., a tumor-associated polypeptide antigen target, and generally binds to the antigen with sufficient affinity so that the antibody is useful as a therapeutic when targeted to cells or tissues expressing the antigen, and does not significantly cross-react with other proteins or proteins other than orthologs and variants (e.g., mutant forms, splice variants, or proteolytically truncated forms) of said antigen target. -4 Less than M or about 10 -5 Less than M or about 10 -6 Less than M or about 10 -7 Less than M or about 10 -8 Less than M or about 10 -9 Less than M or about 10 -10 Less than M or about 10 -11 Less than M or about 10 -12 Monovalent K for antigens less than or equal to M DThe antibody can be demonstrated by an antibody, or an antigen-binding fragment thereof, having the following characteristics: An antibody "specifically binds to," "is specific for," or "specifically recognizes" an antigen if it can distinguish between the antigen and one or more reference antigens. In their most general form, "specific binding," "specific binding to," "specific for," or "specifically recognizes" refers to the antibody's ability to distinguish between an antigen of interest and unrelated antigens, as determined, for example, by any of the following methods: surface plasmon resonance (SPR), Western blot, ELISA, RIA, ECL, IRMA assay, and peptide scanning. For example, a standard ELISA assay can be performed. Scoring can be performed by standard color development (e.g., secondary antibody with horseradish peroxidase and tetramethylbenzidine with hydrogen peroxide). The reaction in a particular well is scored by optical density, for example, at 450 nm. A typical background (=negative reaction) can be 0.1 OD; a typical positive reaction can be 1 OD. This means that the difference between positive and negative is 5-fold or more, 10-fold or more, 50-fold or more, and preferably 100-fold or more. Typically, binding specificity is determined not using a single reference antigen, but using a set of about 3-5 unrelated antigens, such as milk powder, BSA, transferrin, etc.

[0054] "Binding affinity" or "affinity" generally refers to the strength of the sum total of non-covalent interactions between a single binding site of a molecule and its binding partner. Unless otherwise indicated, as used herein, "binding affinity" refers to the intrinsic binding affinity that reflects a 1:1 interaction between members of a binding pair (e.g., an antibody and an antigen). The dissociation constant "K D" is generally used to describe the affinity between a molecule (e.g., an antibody) and its binding partner (e.g., an antigen), i.e., how tightly a ligand binds to a particular protein. Ligand-protein affinity is influenced by non-covalent intermolecular interactions between the two molecules. Affinity can be measured by common methods known in the art, including those described herein. In one embodiment, "K" in accordance with the present invention is D " or "K D The "value" is measured by using a surface plasmon resonance assay using a suitable device, including but not limited to a Biacore instrument such as a Biacore T100, Biacore T200, Biacore 2000, Biacore 4000, Biacore 3000 (GE Healthcare Biacore, Inc.), or a ProteOn XPR36 instrument (Bio-Rad Laboratories, Inc.).

[0055] The term "antibody drug conjugate" or abbreviated ADC is well known to those skilled in the art and, as used herein, generally refers to the linkage of an antibody or antigen-binding fragment thereof with a drug such as a chemotherapeutic agent, a toxin, an immunotherapeutic agent, an imaging probe, and the like.

[0056] The present disclosure also relates to "pharmaceutically acceptable salts." Any pharmaceutically acceptable salt can be used. In particular, the term "pharmaceutically acceptable salts" refers to salts of the conjugates or compounds of the present invention that are pharmaceutically acceptable and possess the desired pharmacological activity of the parent compound. In particular, such salts have low toxicity and can be inorganic or organic acid addition salts and base addition salts. Specifically, such salts include (1) salts formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or salts formed with acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, 4-methylbicyclo[2.2 or (2) salts formed when an acidic proton present in the parent compound is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or when coordinated with an organic base, e.g., ethanolamine, diethanolamine, triethanolamine, N-methylglucamine, etc. Salts further include, but are not limited to, salts formed with organic acids such as .2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, etc. Salts further include, purely by way of example, sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium, etc.; and, if the compound contains a basic functionality, salts of non-toxic organic or inorganic acids, e.g., hydrochloride, hydrobromide, tartrate, mesylate, acetate, maleate, oxalate, etc. Counterions or anionic counterions can be used in quaternary amines to maintain electronic neutrality. Exemplary counterions include halide ions (e.g., F -, Cl - , Br - , I - ), NO3 - , ClO4 - , O.H. - , H2PO4 - , HSO4 - , sulfonate ions (e.g., methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, 10-camphorsulfonic acid, naphthalene-2-sulfonic acid, naphthalene-1-sulfonic acid-5-sulfonic acid, etc.), and carboxylate ions (e.g., acetic acid, ethanoic acid, propanoic acid, benzoic acid, glyceric acid, lactic acid, tartaric acid, glycolic acid, etc.).

[0057] As used herein, the term "solvate" may refer to an aggregate containing one or more molecules of a conjugate or compound described herein and one or more molecules of a solvent. The solvent may be water, in which case the solvate may be a hydrate. Alternatively, the solvent may be an organic solvent. Thus, the conjugate or compound of the present disclosure may exist as a hydrate, including a monohydrate, a dihydrate, a hemihydrate, a sesquihydrate, a trihydrate, a tetrahydrate, etc., as well as corresponding solvated forms. The compounds of the present invention may be true solvates, while in other cases, the compounds of the present invention may simply retain incidental water or may be a mixture of water and incidental solvent.

[0058] Conjugates of formula (I) As indicated above, the present invention provides a conjugate having formula (I): TIFF2024540692000038.tif35128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: RBM is a receptor binding molecule; TIFF2024540692000039.tif6128 is a double bond; or TIFF2024540692000040.tif6128 is a single bond; V is absent if TIFF2024540692000041.tif6128 is a double bond; or V is TIFF2024540692000042.tif6128 is a single bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000043.tif6128 is a double bond, then R3-C; or X is If TIFF2024540692000044.tif6128 is a single bond, TIFF2024540692000045.tif9128; Y is NR 5 , S, O, or CR 6 R 7 and; R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20.

[0059] The conjugate of formula (I) comprises a receptor-binding molecule linked to a camptothecin moiety via a phosphorus(V) moiety (the phosphorus(V) moiety may also be designated "P5") and a linker. The conjugate of formula (I) has been found to have many advantages, as shown below.

[0060] As a first advantage, the conjugate of Formula (I) exhibits good hydrophilicity and low aggregation in solution and during the conjugation process to antibodies, as exemplified by the high yield of ADCs with no or minimal aggregate formation (Example 2 and Figures 18-41). Furthermore, the conjugate of Formula (I) exhibits good cytotoxicity, selective for the cell line targeted by the antibody. The selectivity exceeds that of the commercially available product Enferz (Example 4 and Figures 43-46). The conjugate of Formula (I) also exhibits favorable bystander effects that are comparable to or even better than Enferz (Example 5 and Figure 47, Example 16 and Figure 59, and Example 17 and Figure 60). Furthermore, the conjugate of Formula (I) exhibits good DNA damage in cancer cells (Example 6 and Figure 48). In particular, the conjugate of Formula (I) exhibits excellent serum stability, exceeding that of the commercially available product Enferz (Example 7 and Figure 49). As another advantage over Enhertz, the conjugates of formula (I) maintain their potency and selectivity after incubation in human and rodent serum for a certain period of time in vitro (Example 8 and Figures 50 and 51). This effect, combined with their excellent stability in the presence of serum, may help reduce side effects during patient treatment with the conjugates. The conjugates of formula (I) also exhibit favorable pharmacokinetic properties in vivo (Example 9 and Figure 52, and Example 23 and Figure 67). In particular, in vivo pharmacokinetic experiments performed with the conjugates of formula (I) demonstrated similar clearance compared to Enhertz. Furthermore, the pharmacokinetic experiments demonstrated a further advantage: the conjugates of formula (I) exhibit significantly higher stability in vivo compared to Enhertz (Example 19 and Figure 62). Furthermore, in vivo pharmacokinetic experiments revealed that the conjugate of Formula (I) was cleared with kinetics very similar to that of the unmodified antibody, even under high camptothecin drug loads; and the long-term stability of the conjugate of Formula (I) in the circulation in vivo was demonstrated (Example 21 and Figure 65). The conjugate of Formula (I) also has similar thermal stability compared to Enherz (Example 10 and Figure 53).The conjugate of Formula (I) and Enferz also exhibit similar binding properties to extracellular targets (Example 11 and Figure 54). As a further advantage, the conjugate of Formula (I) also exhibits reduced aggregation compared to Enferz over incubation times of up to several weeks in aqueous media (Example 12 and Figure 55). As another advantage, the conjugate of Formula (I) also exhibits enhanced antibody-dependent cellular cytotoxicity (ADCC) compared to Enferz (Example 13 and Figure 56). The inventors further observed that the conjugate of Formula (I) exhibits similar internalization into target-positive (Her2+) cells compared to Enferz, while undesired internalization into target-negative cells is reduced (Example 14 and Figure 57). The conjugate of Formula (I) also exhibits better in vitro efficacy compared to Enferz for cell lines that do not highly overexpress the target (Example 16 and Figure 58). Thus, the conjugates described herein have improved properties compared to Enherz in terms of efficacy, particularly in cells with low target expression. The inventors also found that the conjugates of Formula (I) have the advantage of exhibiting less undesirable toxicity to various cells in healthy human tissues compared to Enherz (Example 18 and Figure 61). The superior efficacy of the conjugates of Formula (I) for tumor treatment was demonstrated in vivo (Example 20, Figures 63 and 64). In particular, dose-dependence and superior in vivo efficacy compared to Enherz were demonstrated (Example 24 and Figure 68). Furthermore, the conjugates of Formula (I) can be prepared with various ratios of camptothecin moiety to receptor-binding molecule (see Examples 2 and 3 and Figure 42, and Example 22 and Figure 66).In summary, the inventors have surprisingly found that conjugates of formula (I) exhibit superior properties that make them useful as pharmaceuticals, including, for example, improved serum stability and other advantages such as favorable bystander effects, good pharmacokinetic properties in vivo, long-term stability in vivo, reduced aggregation, enhanced ADCC, reduced undesired internalization into target-negative cells, better efficacy against cell lines with low target expression, reduced undesired toxicity to cells of healthy human tissues, and superior efficacy for the treatment of tumors in vivo. It is noted that conjugates containing phosphorus (V) moieties are described, for example, in WO 2018 / 041985 A1 and WO 2019 / 170710, which are incorporated herein by reference.

[0061] Preferably R 3 is H or (C1-C8) alkyl; more preferably R 3 is H. Preferably R 4 When present, R is H or (C-C) alkyl; more preferably R 4 When present, R is H. Preferably, R 5 When present, R is H or (C-C) alkyl; more preferably R 5 When present, R is H. Preferably, R 6 When present, R is H or (C-C) alkyl; more preferably R 6 When present, R is H. Preferably, R 7 When present, R is H or (C-C) alkyl; more preferably R 7 is H, if present.

[0062] Preferably, TIFF2024540692000046.tif6128 is a double bond; V is absent; X is R3-C; and R 3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 3is H or (C1-C8) alkyl; more preferably R 3 is H.

[0063] More preferably, TIFF2024540692000047.tif6128 represents a double bond; V is absent; X represents R-C, and R represents H or (C-C) alkyl. Preferably, R 3 represents H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. In a preferred embodiment, R3 is H.

[0064] In some embodiments, TIFF2024540692000048.tif6128 can be a single bond; V is H or (C1-C8) alkyl, preferably V is H; X is TIFF2024540692000049.tif9128; R3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; more preferably R 3 is H or (C1-C8) alkyl, more preferably R 3 is H;R 4 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably, R 4 is H or (C-C) alkyl, preferably R 4 is H.

[0065] In some embodiments, TIFF2024540692000050.tif6128 can represent a bond; V can be H or (C1-C8) alkyl; X can be TIFF2024540692000051.tif9128; and R3 and R4 may independently represent H or (C1-C8) alkyl. Preferably, R3 and R4 independently represent H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. Preferably, R3 and R4 are the same; even more preferably, R3, R4 and V are the same. More preferably, R3 and R4 are both H. Preferably, V is H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. Even more preferably, V is H. In a preferred embodiment, R3, R4 and V are each H.

[0066] The integer m ranges from 1 to 10. Thus, the integer m can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Preferably, the integer m ranges from 1 to 4. More preferably, the integer m is 1 or 2. Even more preferably, the integer m is 1.

[0067] The integer n is in the range of 1 to 20. Thus, the integer n can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. Preferably, the integer n is in the range of 1 to 10. More preferably, the integer n is in the range of 2 to 10. Even more preferably, the integer n is in the range of 4 to 10. Even more preferably, the integer n is in the range of 6 to 10. Even more preferably, the integer n is 6, 7, 8, 9, or 10. Even more preferably, the integer n is in the range of 7 to 10. Even more preferably, the integer n is 7, 8, or 9. Even more preferably, the integer n is 7 or 8. Even more preferably, the integer n is 8.

[0068] The integer n is in the range of 1 to 20. Preferably, the integer n is in the range of 1 to 10. More preferably, the integer n is in the range of 2 to 8. Even more preferably, the integer n is 2, 3, 4, 5, or 6. Even more preferably, the integer n is in the range of 3 to 6. Even more preferably, the integer n is 3, 4, or 5. Even more preferably, the integer n is 4 or 5. Even more preferably, the integer n is 4.

[0069] Preferably, m is an integer in the range of 1 to 4, more preferably 1 or 2, even more preferably 1; and preferably n is an integer in the range of 1 to 20, more preferably 1 to 10, even more preferably 2 to 10, even more preferably 4 to 10, even more preferably 6 to 10, even more preferably n is 6, 7, 8, 9 or 10, even more preferably n is 7 to 10, even more preferably 7 to 10; even more preferably n is 7, 8 or 9, even more preferably n is 7 or 8, and even more preferably n is 8.

[0070] Preferably, m is an integer in the range of 1 to 4, preferably 1 or 2, more preferably 1; and preferably n is an integer in the range of 1 to 20, more preferably 1 to 10, even more preferably 2 to 8; even more preferably n is 2, 3, 4, 5 or 6; even more preferably n is in the range of 3 to 6; even more preferably n is 3, 4 or 5; even more preferably n is 4 or 5; and even more preferably n is 4.

[0071] Preferably, m is 1; and preferably, n is an integer in the range of 1 to 20, more preferably 1 to 10, even more preferably 2 to 10, even more preferably 4 to 10, even more preferably 6 to 10, even more preferably, n is 6, 7, 8, 9, or 10, even more preferably, n is in the range of 7 to 10, even more preferably, n is 7, 8, or 9, even more preferably, n is 7 or 8, and still more preferably, n is 8. Thus, preferably, m is 1, and n is an integer in the range of 1 to 20. More preferably, m is 1, and n is an integer in the range of 1 to 10. Even more preferably, m is 1, and n is an integer in the range of 2 to 10. Even more preferably, m is 1, and n is an integer in the range of 4 to 10. Even more preferably, m is 1, and n is an integer in the range of 6 to 10. Even more preferably, m is 1, and n is 6, 7, 8, 9, or 10. Even more preferably, m is 1 and n is an integer in the range of 7 to 10. Even more preferably, m is 1 and n is 7, 8, or 9. Even more preferably, m is 1 and n is 7 or 8. Even more preferably, m is 1 and n is 8.

[0072] Preferably, m is 1; and preferably, n is an integer in the range of 1 to 20, more preferably 1 to 10, even more preferably 2 to 8; even more preferably, n is 2, 3, 4, 5, or 6, even more preferably, n is in the range of 3 to 6; even more preferably, n is 3, 4, or 5; even more preferably, n is 4 or 5; and still more preferably, n is 4. Thus, preferably, m is 1 and n is an integer in the range of 1 to 20. More preferably, m is 1 and n is an integer in the range of 1 to 10. Even more preferably, m is 1 and n is an integer in the range of 2 to 8. Even more preferably, m is 1 and n is 2, 3, 4, 5, or 6. Even more preferably, m is 1 and n is in the range of 3 to 6. Even more preferably, m is 1 and n is 3, 4, or 5. Even more preferably, m is 1 and n is 4 or 5. Even more preferably, m is 1 and n is 4.

[0073] In some embodiments, the number of camptothecin moieties C per receptor-binding molecule can be 1 to 20. Preferably, the number of camptothecin moieties C per receptor-binding molecule is 1 to 14. More preferably, the number of camptothecin moieties C per receptor-binding molecule is 2 to 14. More preferably, the number of camptothecin moieties C per receptor-binding molecule is 4 to 14. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 5 to 12. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 6 to 12. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 7 to 10. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 8.

[0074] In some embodiments, the number of camptothecin moieties C per receptor-binding molecule can be 1 to 20. Preferably, the number of camptothecin moieties C per receptor-binding molecule is 1 to 14. More preferably, the number of camptothecin moieties C per receptor-binding molecule is 1 to 12. More preferably, the number of camptothecin moieties C per receptor-binding molecule is 2 to 10. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 2 to 8. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 2 to 6. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 3 to 5. Even more preferably, the number of camptothecin moieties C per receptor-binding molecule is 4.

[0075] Receptor-binding molecules (RBM) RBM is a receptor-binding molecule. The term "receptor-binding molecule" generally refers to any molecule that can bind to a receptor. As an illustrative but non-limiting example, the receptor that the receptor-binding molecule can bind to may be expressed on the cell surface. As an illustrative but non-limiting example, the cell that expresses the receptor may be a cancer cell. Those skilled in the art will know how to select a suitable receptor-binding molecule.

[0076] The receptor may be a tumor-associated surface antigen. Thus, the receptor-binding molecule can specifically bind to the tumor-associated surface antigen. The term "tumor-associated surface antigen," as used herein, generally refers to an antigen that is or can be presented on the surface of a tumor cell or tumor cell. These antigens may have an extracellular portion presented on the cell surface, which is often combined with the transmembrane and cytoplasmic portions of the molecule. In some embodiments, these antigens may be presented only by tumor cells and not by normal, i.e., non-tumor cells. Tumor antigens may be expressed only on tumor cells or may exhibit tumor-specific mutations compared to non-tumor cells. In such embodiments, each antigen may be referred to as a tumor-specific antigen. Some antigens may be presented by both tumor and non-tumor cells and may be referred to as tumor-associated antigens. These tumor-associated antigens may be overexpressed in tumor cells compared to non-tumor cells and be accessible to antibody binding on tumor cells due to the less compact structure of tumor tissue compared to non-tumor tissue. In some embodiments, tumor-associated surface antigens are located on the tumor vasculature. Illustrative, but non-limiting, examples of tumor-associated surface antigens include CD19, CD30, Her2, or PMSA. Tumor-associated surface antigens are known to those skilled in the art. In particular, those known to be useful for the development of ADCs are described in the review article, for example, Criscitello et al., "Antibody-drug conjugates in solid tumors: a look into novel targets", Journal of Hematology and Oncology, (2021) 14:20 (https: / / doi.org / 10.1186 / s13045-021-01035-z).

[0077] The receptor binding molecule may be selected from the group consisting of antibodies, antibody fragments, and proteinaceous binding molecules with antibody-like binding properties.

[0078] Preferably, the receptor-binding molecule is an antibody. More preferably, the antibody is selected from the group consisting of monoclonal antibodies, chimeric antibodies, humanized antibodies, human antibodies, and single-domain antibodies, such as camel or shark single-domain antibodies. Even more preferably, the antibody is a monoclonal antibody. Preferably, the antibody is capable of specifically binding to a tumor-associated surface antigen. In some embodiments, the antibody may be brentuximab. In some embodiments, the antibody may be trastuzumab.

[0079] The receptor-binding molecule may be an antibody fragment. Preferably, the antibody fragment is a bivalent antibody fragment. More preferably, the bivalent antibody fragment is selected from the group consisting of a (Fab)2' fragment, a bivalent single-chain Fv fragment, a dual affinity re-targeting (DART) antibody, and a diabody. Alternatively, preferably, the antibody fragment is a monovalent antibody fragment. More preferably, the monovalent antibody fragment is selected from the group consisting of a Fab fragment, an Fv fragment, and a single-chain Fv fragment (scFv). The monovalent antibody fragment may be a fragment of a single-domain camelid or shark single-domain antibody. Preferably, the antibody fragment is capable of specifically binding to a tumor-associated surface antigen.

[0080] The receptor-binding molecule may be a proteinaceous binding molecule with antibody-like binding properties. Examples of proteinaceous binding molecules with antibody-like binding properties that can be used as receptor-binding molecules include aptamers, muteins based on polypeptides of the lipocalin family, glubodies, proteins based on ankyrin scaffolds, proteins based on crystallin scaffolds, adnectins, avimers, EGF-like domains, kringle domains, fibronectin type I domains, fibronectin type II domains, fibronectin type III domains, PAN domains, G1a domains, SRCR domains, and Kunitz / bovine pancreatic trypsin inhibitor. domain, tendamistat, Kazal-type serine protease inhibitor domain, trefoil (P-type) domain, von Willebrand factor type C domain, anaphylatoxin-like domain, CUB domain, thyroglobulin type I repeat, LDL receptor class A domain, sushi domain, link domain, thrombospondin type I domain, immunoglobulin domain or immunoglobulin-like domain (e.g., domain antibody or camel heavy chain antibody), C-type lectin domain, MAM domain, von Willebrand factor type A domain, somatomedin B domain, WAP-type 4-disulfide core domain, F5 / 8 C-type domain, hemopexin domain, SH2 domain, SH3 domain, laminin-type EGF-like domain, C2 domain, "kappabody" (Ill. et al. "Design and construction of a hybrid immunoglobulin domain with properties of both heavy and light chain variable regions" Protein Eng 10:949-57 (1997)), "minibody" (Martin et al. "The affinity-selection of a minibody polypeptide inhibitor of human interleukin-6" EMBO J 13:5303-9 (1994)), "Janusin" (Traunecker et al."Bispecific single chain molecules (Janusins) target cytotoxic lymphocytes on HIV-infected cells" EMBO J 10:3655-3659 (1991) and Traunecker et al. "Janusin: new molecular design for bispecific reagents" Int J Cancer Suppl 7:51-52 (1992), nanobodies, adnectins, tetranectins, microbodies, affilins, affibodies or ankyrins, crystallins, knottins, ubiquitins, zinc finger proteins, autofluorescent proteins, ankyrins or ankyrin repeat proteins or leucine-rich repeat proteins, avimers (Silverman, Lu Q, Bakker A, To W, Duguay A, Alba BM, Smith R, Rivas A, Li P, Le H, Whitehorn E, Moore KW, Swimmer C, Perlroth V, Vogt M, Kolkman J, Stemmer WP 2005, Nat Biotech, Dec;23(12):1556-61, E-Publication in Nat Biotech. 2005 Nov 20 edition); and Silverman J, Lu Q, Bakker A, To W, Duguay A, Alba BM, Smith R, Rivas A, Li P, Le H, Whitehorn E, Moore KW, Swimmer C, Perlroth V, Vogt M, Kolkman J, Stemmer WP, Nat Biotech, Dec;23(12):1556-61, E-Publication in Nat. Biotechnology.Examples of suitable proteinaceous binding molecules include, but are not limited to, multivalent avimer proteins evolved by exon shuffling of human receptor domain families, as described in the 2005 Nov 20 edition. Preferably, the proteinaceous binding molecule with antibody-like binding properties is selected from the group consisting of muteins based on polypeptides of the lipocalin family, glubodies, proteins based on ankyrin scaffolds, proteins based on crystallin scaffolds, adnectins, avimers, DARPins, and affibodies. Preferably, the proteinaceous binding molecule with antibody-like binding properties is capable of specifically binding to tumor-associated surface antigens.

[0081] Base Y The group Y is NR 5 , S, O, and CR 6 R 7 R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 5 is H or (C1-C8) alkyl; more preferably R 5 is H. R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 6 is H or (C1-C8) alkyl; more preferably R 6 is H. R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 7 is H or (C1-C8) alkyl; more preferably R 7 is H.

[0082] Preferably, Y is selected from the group consisting of NH, S, O, and CH. More preferably, Y is NH, S, or O. In some embodiments, Y is CH. In some embodiments, Y is O. In some embodiments, Y is S.

[0083] In a highly preferred embodiment, Y is NH.

[0084] base R 1 R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue.

[0085] R 1 may represent optionally substituted (C1-C8) alkyl.

[0086] R 1 may represent (C-C)alkyl optionally substituted with at least one of F, Cl, Br, I, —NO, —N((C-C)alkyl)H, —NH, —N, —N((C-C)alkyl), ═O, (C-C)cycloalkyl, —SS—((C-C)alkyl), (C-C)alkenyl, or (C-C)alkynyl.

[0087] R 1 may represent optionally substituted phenyl.

[0088] R 1 may represent phenyl optionally independently substituted with at least one of (C1-C8)alkyl, F, Cl, I, Br, —NO2, —N((C1-C8)alkyl)H, —NH2, or —N((C1-C8)alkyl)2.

[0089] R 1 may represent an optionally substituted 5- or 6-membered aromatic heterocycle, such as, for example, pyridyl.

[0090] R 1 may represent (C1-C8) alkyl, (C1-C8) alkyl substituted with -SS-(C1-C8) alkyl, (C1-C8) alkyl substituted with optionally substituted phenyl; or phenyl; or phenyl substituted with -NO2.

[0091] R 1may represent methyl, ethyl, propyl or butyl, preferably methyl or ethyl, more preferably ethyl.

[0092] First polyalkylene glycol unit R F Preferably, R 1 is the first polyalkylene glycol unit R F The term "first polyalkylene glycol unit," as used herein, refers to a polyalkylene glycol unit bonded to an O atom that is connected to the phosphorus of the phosphorus(V) moiety. F comprises at least one alkylene glycol subunit. Preferably, the first polyalkylene glycol unit R F has the following structure: More preferably, the first polyalkylene glycol unit R F has the following structure: TIFF2024540692000053.tif15128. Thus, the first polyalkylene glycol unit R F can be a polytetramethylene glycol unit, a polypropylene glycol unit, or a polyethylene glycol unit. Even more preferably, the first polyalkylene glycol unit R F has the following structure: TIFF2024540692000054.tif14128 and contains one or more alkylene glycol subunits.

[0093] Preferably, the first polyalkylene glycol unit R F comprises 1 to 100 alkylene glycol subunits as described herein. More preferably, the first polyalkylene glycol unit R F comprises 2 to 50 alkylene glycol subunits as described herein. Even more preferably, the first polyalkylene glycol unit RF comprises 3 to 45 alkylene glycol subunits as described herein. Even more preferably, the first polyalkylene glycol unit R F comprises 4 to 40 alkylene glycol subunits as described herein. Even more preferably, the first polyalkylene glycol unit R F comprises 6 to 35 alkylene glycol subunits as described herein. Even more preferably, the first polyalkylene glycol unit R F contains 8 to 30 alkylene glycol subunits as described herein.

[0094] Preferably, the first polyalkylene glycol unit R F comprises 1 to 20 alkylene glycol subunits as described herein. More preferably, the first polyalkylene glycol unit R F comprises 2 to 12 alkylene glycol subunits as described herein. Even more preferably, the first polyalkylene glycol unit R F contains 3 to 11 alkylene glycol subunits as described herein.

[0095] First polyalkylene glycol unit R F The structure: The first polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits having the formula TIFF2024540692000055.tif15128. Preferably, the first polyalkylene glycol unit R F The structure: The first polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits having the formula TIFF2024540692000056.tif15128. More preferably, the first polyalkylene glycol unit RF The structure: In a highly preferred embodiment, the first polyalkylene glycol unit R F The structure: It may be a polyethylene glycol unit containing 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits each having the formula TIFF2024540692000058.tif10128.

[0096] First polyalkylene glycol unit R F The structure: The first polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000059.tif15128. Preferably, the first polyalkylene glycol unit R F The structure: The first polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000060.tif15128. More preferably, the first polyalkylene glycol unit R F The structure: In a highly preferred embodiment, the first polyalkylene glycol unit R F The structure: TIFF2024540692000062.tif10128, and may be a polyethylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits each having the formula: TIFF2024540692000062.tif10128.

[0097] Preferably, the first polyalkylene glycol unit R F teeth, TIFF2024540692000063.tif15128, where: TIFF2024540692000064.tif10128 shows the position of the O connected to the phosphorus; K F is H or a first capping group; preferably K F are -H (hydrogen), -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 ) alkyl-N((C1-C3) alkyl)2; more preferably K F is H; and o is an integer ranging from 1 to 100.

[0098] A "first capping group," as referred to herein, can be any moiety that can function as the terminal group of a first polyalkylene glycol unit. Examples of first capping groups that can be used in the present disclosure include -POH, -(C-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 In some embodiments, the first capping group is -(C-C) alkyl-N((C-C) alkyl). 10 ) alkyl, especially methyl.

[0099] Preferably, K F is H (hydrogen).

[0100] The integer o represents the repeating unit in the first polyalkylene glycol unit: TIFF2024540692000065.tif12128 represents the number. The integer o can be in the range of 1 to 100. Preferably, o is in the range of 2 to 50. More preferably, o is in the range of 3 to 45. Even more preferably, o is in the range of 4 to 40. Even more preferably, o is in the range of 6 to 35. Even more preferably, o is in the range of 8 to 30. In a preferred embodiment, o is 12 or about 12. Even more preferably, o is in the range of 16 to 30. Even more preferably, o is in the range of 20 to 28. Even more preferably, o is 22, 23, 24, 25, or 26. Even more preferably, o is 23, 24, or 25. In a preferred embodiment, o is 24 or about 24. Preferably, the repeating unit is TIFF2024540692000066.tif11128. More preferably, the repeating unit is The file is TIFF2024540692000067.tif12128.

[0101] In the first polyalkylene glycol unit, the integer o can range from 1 to 20. Preferably, o ranges from 2 to 12. More preferably, o ranges from 3 to 11. Preferably, the repeating unit is TIFF2024540692000068.tif11128. More preferably, the repeating unit is TIFF2024540692000069.tif12128.

[0102] Preferably, the first polyalkylene glycol unit R F has the following structure: TIFF2024540692000070.tif10128, i.e., the subunit is designated as an ethylene glycol subunit. Thus, preferably, the first polyalkylene glycol unit is a first polyethylene glycol unit. The first polyethylene glycol unit includes at least one ethylene glycol subunit.

[0103] Preferably, the first polyalkylene glycol unit R F The structure: The first polyethylene glycol unit may include 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 ethylene glycol subunits each having the formula TIFF2024540692000071.tif9128.

[0104] Preferably, the first polyalkylene glycol unit R F The structure: The first polyethylene glycol unit may be a first polyethylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 ethylene glycol subunits each having the formula TIFF2024540692000072.tif9128.

[0105] Preferably, the first polyalkylene glycol unit R F The structure: a first polyethylene glycol unit having TIFF2024540692000073.tif15128; where: TIFF2024540692000074.tif10128 shows the position of the O connected to the phosphorus; K F is H (hydrogen) or a first capping group as described herein; preferably K F are -H (hydrogen), -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 ) alkyl-N((C1-C3) alkyl)2; more preferably K F is H; and o is an integer ranging from 1 to 100.

[0106] The integer o is the repeating unit in the first polyethylene glycol unit: TIFF2024540692000075.tif12128 represents the number. The integer o can be in the range of 1 to 100. Preferably, o is in the range of 2 to 50. More preferably, o is in the range of 3 to 45. Even more preferably, o is in the range of 4 to 40. Even more preferably, o is in the range of 6 to 35. Even more preferably, o is in the range of 8 to 30. In a preferred embodiment, o is 12 or about 12. Even more preferably, o is in the range of 16 to 30. Even more preferably, o is in the range of 20 to 28. Even more preferably, o is 22, 23, 24, 25, or 26. Even more preferably, o is 23, 24, or 25. In a preferred embodiment, o is 24 or about 24.

[0107] In the first polyethylene glycol unit, the integer o can be in the range of 1 to 20. Preferably, o is in the range of 2 to 12. More preferably, o is in the range of 3 to 11.

[0108] Generally, the first polyalkylene glycol unit R FIn the (preferably first polyethylene glycol unit), polydisperse polyalkylene glycols (preferably polydisperse polyethylene glycols), monodisperse polyalkylene glycols (preferably monodisperse polyethylene glycols), and individual polyalkylene glycols (preferably individual polyethylene glycols) can be used. Polydisperse polyalkylene glycols (preferably polydisperse polyethylene glycols) are heterogeneous mixtures of sizes and molecular weights, whereas monodisperse polyalkylene glycols (preferably monodisperse polyethylene glycols) are typically purified from heterogeneous mixtures and thus provide a single chain length and molecular weight. A preferred first polyalkylene glycol unit is an individual polyalkylene glycol (preferably individual polyethylene glycol), i.e., a compound that is synthesized stepwise rather than by a polymerization process. An individual polyalkylene glycol (preferably individual polyethylene glycol) provides a single molecule with a defined and specified chain length.

[0109] The first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) provided herein comprises one or more polyalkylene glycol chains (preferably, polyethylene glycol chains). The polyalkylene glycol chains (preferably, polyethylene glycol chains) can be linked together, for example, in a linear, branched, or star configuration. Optionally, at least one of the polyalkylene glycol chains (preferably, polyethylene glycol chains) can be derivatized at one end for covalent attachment to an oxygen atom bonded to phosphorus.

[0110] The first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) is connected to the conjugate (or an intermediate thereof) at an oxygen atom bonded to phosphorus. The other end(s) of the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) is free and untethered and may take the form of a hydrogen, methoxy, carboxylic acid, alcohol, or other suitable functional group, such as, for example, any first capping group as described herein. The methoxy, carboxylic acid, alcohol, or other suitable functional group acts as a cap for the terminal polyalkylene glycol subunit (preferably, the polyethylene glycol subunit) of the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit). By untethered, it is meant that the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) is not connected at its untethered position to the camptothecin moiety (C), the receptor-binding molecule, or a component of the linker (L) linking the camptothecin moiety and / or the receptor-binding molecule. For embodiments in which the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) comprises more than one polyalkylene glycol chain (preferably, a polyethylene glycol chain), the multiple polyalkylene glycol chains (preferably, polyethylene glycol chains) may be the same or different chemical moieties (e.g., polyalkylene glycols, particularly polyethylene glycols, of different molecular weights or subunit numbers). The multiple first polyalkylene glycol chains (preferably, the first polyethylene glycol chains) are attached at a single attachment site to the oxygen atom bonded to the phosphorus.Those skilled in the art will understand that the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit), in addition to comprising repeating polyalkylene glycol subunits (preferably, polyethylene glycol subunits), may further contain a non-polyalkylene glycol material (preferably, a non-polyethylene glycol material) (e.g., to facilitate coupling of multiple polyalkylene glycol chains (preferably, polyethylene glycol chains) to one another or to facilitate coupling to the oxygen atom attached to the phosphorus). The non-polyalkylene glycol material (preferably, a non-polyethylene glycol material) refers to atoms in the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) that are not part of a repeating alkylene glycol subunit (preferably, a -CHCHO- subunit). In embodiments provided herein, the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) may comprise two monomeric polyalkylene glycol chains (preferably, polyethylene glycol chains) linked to one another via a non-polyalkylene glycol (non-polyethylene glycol) element. In other embodiments provided herein, the first polyalkylene glycol unit (preferably, the first polyethylene glycol unit) can comprise two linear polyalkylene glycol chains (preferably, polyethylene glycol chains) connected to a central core that is connected to an oxygen atom bonded to phosphorus (i.e., the polyalkylene glycol unit (preferably, the polyethylene glycol unit) is branched).

[0111] There are numerous methods for attaching polyalkylene glycols (preferably polyethylene glycols) available to those skilled in the art [see, e.g., EP 0 401 384 (PEG coupling to G-CSF); U.S. Pat. No. 5,757,078 (PEGylation of EPO peptides); U.S. Pat. No. 5,672,662 (Polyethylene glycols monosubstituted with propionic or butanoic acid and their functional derivatives for biotechnological applications) and related polymers; U.S. Pat. No. 6,077,939 (PEGylation of the N-terminal α-carbon of peptides); and Veronese (2001) Biomaterials 22:405-417 (review on peptide and protein PEGylation)].

[0112] In preferred embodiments, the first polyalkylene glycol unit, more preferably the first polyethylene glycol unit, is directly attached to the oxygen atom attached to the phosphorus. In these embodiments, the first polyalkylene glycol unit, preferably the first polyethylene glycol unit, does not include a functional group for attachment to the oxygen atom attached to the phosphorus, i.e., the oxygen atom is directly attached to a carbon atom of the first polyalkylene glycol unit, preferably to the CH2 of the first polyethylene glycol unit.

[0113] In one group of embodiments, the first polyalkylene glycol unit comprises at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three alkylene glycol subunits, even more preferably at least four alkylene glycol subunits, even more preferably at least six alkylene glycol subunits, and even more preferably at least eight alkylene glycol subunits. In some such embodiments, the first polyalkylene glycol unit comprises no more than about 100 alkylene glycol subunits, preferably no more than about 50 alkylene glycol units, more preferably no more than about 45 alkylene glycol subunits, more preferably no more than about 40 alkylene glycol subunits, more preferably no more than about 35 subunits, and even more preferably no more than about 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunit can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000076.tif10128. Preferably, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit, where each alkylene glycol subunit is an ethylene glycol subunit.

[0114] In one group of embodiments, the first polyalkylene glycol unit comprises one or more linear polyalkylene glycol chains each having at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three alkylene glycol subunits, even more preferably at least four alkylene glycol subunits, even more preferably at least six alkylene glycol subunits, and even more preferably at least eight alkylene glycol subunits. In preferred embodiments, the first polyalkylene glycol unit comprises a total of at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three, even more preferably at least four, even more preferably at least six, or even more preferably at least eight alkylene glycol subunits. In some such embodiments, the first polyalkylene glycol unit comprises a total of about 100 or less alkylene glycol subunits, preferably a total of about 50 or less alkylene glycol subunits, more preferably a total of about 45 or less subunits, even more preferably a total of about 40 or less subunits, even more preferably a total of about 35 or less subunits, and even more preferably a total of about 30 or less subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000077.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit comprising one or more linear polyethylene glycol chains.

[0115] In another group of embodiments, the first polyalkylene glycol unit comprises a total of 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000078.tif10128. Preferably, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit, where each alkylene glycol subunit is an ethylene glycol subunit.

[0116] In another group of embodiments, the first polyalkylene glycol unit comprises one or more linear polyalkylene glycol chains having a total of 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000079.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit comprising one or more linear polyethylene glycol chains.

[0117] In another group of embodiments, the first polyalkylene glycol unit is a linear single polyalkylene glycol chain having at least one subunit, preferably at least two subunits, more preferably at least three subunits, even more preferably at least six subunits, and even more preferably at least eight subunits. In any one of these embodiments, the alkylene glycol subunit can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000080.tif9128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit that is a linear single polyethylene glycol chain. Optionally, in any one of these embodiments, the linear single polyalkylene glycol chain can be derivatized.

[0118] In another group of embodiments, the polyalkylene glycol unit is a linear single polyalkylene glycol chain having 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, more preferably 6 to 35, and more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000081.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit that is a linear single polyethylene glycol chain. Optionally, in any one of these embodiments, the linear single polyalkylene glycol chain can be derivatized.

[0119] In any one of the embodiments provided herein, an exemplary linear polyethylene glycol unit that can be used as the first polyalkylene glycol unit, and particularly as the first polyethylene glycol unit, is as follows: TIFF2024540692000082.tif40128where the wavy line indicates the site of attachment to the oxygen atom bonded to the phosphorus; R 20 is a PEG-linking unit; preferably, R 20 does not exist; R 21 is a PEG capping unit (referred to herein as R 21 is "K F " also appears); R 22 is a PEG coupling unit (i.e., for coupling multiple PEG subunit chains together); n is independently selected from 3 to 100, preferably 3 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30; e is 2 to 5; Each n' is independently selected from 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and even more preferably 8 to 30. In preferred embodiments, there is at least 1, preferably at least 2, more preferably at least 3, more preferably at least 4, more preferably at least 6, and even more preferably at least 8 ethylene glycol subunits in the polyethylene glycol unit. In some embodiments, there are 100 or fewer, preferably 50 or fewer, more preferably 45 or fewer, more preferably 40 or fewer, more preferably 35 or fewer, and even more preferably 30 or fewer ethylene glycol subunits in the polyethylene glycol unit. R 20 When is not present, the (CH2CH2O) subunit is bonded directly to the oxygen atom that is bonded to the phosphorus.

[0120] Preferably, the linear polyethylene glycol unit is TIFF2024540692000083.tif9128, where the wavy line indicates the site of attachment to the oxygen atom bonded to the phosphorus; R 20 , R 21 (referred to herein as "K F ") and n are as defined herein; more preferably R 20 is absent. In a preferred embodiment, n is 12 or about 12. In a preferred embodiment, n is 24 or about 24. Preferably, R 21 is H.

[0121] Polyethylene glycol connecting unit R 20 When present, is part of the first polyethylene glycol unit and acts to link the first polyethylene glycol unit to the oxygen atom attached to the phosphorus. In this regard, the oxygen atom attached to the phosphorus forms a bond with the first polyethylene glycol unit. In an exemplary embodiment, the PEG connecting unit R 20 If present, *-(C1-C 10 ) Alkyl- #, *-arylene- # , *-(C1-C 10 )Alkyl-O- # , *-(C1-C 10 )Alkyl-C(O)- # , *-(C1-C 10 )Alkyl-C(O)O- # , *-(C1-C 10 )Alkyl-NH- # , *-(C1-C 10 )Alkyl-S- # , *-(C1-C 10 )Alkyl-C(O)-NH- # , *-(C1-C 10 )Alkyl-NH-C(O)- # , and *-CH2-CH2SO2-(C1-C 10 ) Alkyl- # wherein * denotes the point of attachment to the oxygen bonded to the phosphorus, and # denotes the point of attachment to the ethylene glycol unit.

[0122] PEG coupling unit R 22 When present, is a non-PEG material that is part of the polyethylene glycol unit and acts to link two or more chains of repeating -CHCHO- subunits. In an exemplary embodiment, the PEG coupling unit R 22 If present, *-(C1-C 10 )Alkyl-C(O)-NH- # , *-(C1-C 10 )Alkyl-NH-C(O)- # , *-(C2-C 10 )Alkyl-NH- # , *-(C2-C 10 )Alkyl-O- # , *-(C1-C 10 )Alkyl-S- # , or *-(C2-C 10 )Alkyl-NH- #where * denotes the point of attachment to the oxygen atom of an ethylene glycol subunit, and # denotes the point of attachment to a carbon atom of another ethylene glycol subunit.

[0123] As used herein, "K F ", also displayed as the group R 21 is H (hydrogen) in exemplary embodiments, or may be a first capping group, as described herein; preferably, R 21 -H, -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 In some embodiments, R21 is independently selected from the group consisting of -C1-C3) alkyl-N((C1-C3) alkyl). 10 ) alkyl, especially methyl. More preferably, R 21 is H.

[0124] In any one of the embodiments provided herein, an illustrative linear first polyethylene glycol unit that can be used as the first polyalkylene glycol unit is as follows: TIFF2024540692000084.tif57128, where the wavy line indicates the site of attachment to the oxygen atom bonded to the phosphorus; and each n is 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30. In some embodiments, n is about 12. In some embodiments, n is about 24.

[0125] In some embodiments, the first polyalkylene glycol unit is about 300 daltons to about 5 kilodaltons; about 300 daltons to about 4 kilodaltons; about 300 daltons to about 3 kilodaltons; about 300 daltons to about 2 kilodaltons; or about 300 daltons to about 1 kilodalton. In some such aspects, the first polyalkylene glycol unit can have at least 6 alkylene glycol subunits or at least 8 alkylene glycol subunits. In some such aspects, the first polyalkylene glycol unit can have at least 6 alkylene glycol subunits or at least 8 alkylene glycol subunits, but not more than 100 alkylene glycol subunits, preferably not more than 50 alkylene glycol subunits. In some embodiments, the first polyalkylene glycol unit is a first polyethylene glycol unit that is about 300 daltons to about 5 kilodaltons; about 300 daltons to about 4 kilodaltons; about 300 daltons to about 3 kilodaltons; about 300 daltons to about 2 kilodaltons; or about 300 daltons to about 1 kilodalton. In some such aspects, the first polyethylene glycol unit can have at least 6 ethylene glycol subunits or at least 8 ethylene glycol subunits. In some such aspects, the first polyethylene glycol unit has at least 6 ethylene glycol subunits or at least 8 ethylene glycol subunits, but not more than 100 ethylene glycol subunits, preferably not more than 50 ethylene glycol subunits.

[0126] In some embodiments, R 1 is the first polyalkylene glycol unit R F , then no other alkylene glycol subunits are present in the conjugate of formula (I) (i.e., no alkylene glycol subunits are present in any of the other components of the conjugate, such as, for example, in the linker L as provided herein). 1is the first polyalkylene glycol unit, then no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 other alkylene glycol subunits are present in the conjugate of Formula (I) (i.e., no more than 8, 7, 6, 5, 4, 3, 2, or 1 other alkylene glycol subunits are present in other components of the conjugate, such as, for example, in a linker L as provided herein).

[0127] Preferably, in other embodiments, R 1 is the first polyalkylene glycol unit R F and the conjugate has a second polyalkylene glycol unit R, as described herein. S Preferably, R 1 is the first polyethylene glycol unit and the conjugate is the second polyalkylene glycol unit R S wherein the second polyalkylene glycol unit is a second polyethylene glycol unit, as described herein.

[0128] It will be understood that when referring to alkylene glycol subunits, particularly ethylene glycol subunits, and depending on the context, the number of subunits may represent an average number, for example, when referring to a population of conjugates or intermediate compounds and using polydisperse polyalkylene glycols, particularly polydisperse polyethylene glycols.

[0129] "L": Linker The present disclosure provides conjugates in which a receptor-binding molecule as described herein is linked to a camptothecin moiety. According to the present disclosure, the receptor-binding molecule can be linked to the camptothecin moiety via a covalent connection by a group Y and a linker L. As used herein, a "linker" L is any chemical moiety capable of linking a group Y, such as NH, to another moiety, such as a camptothecin moiety. In this regard, reference is again made to formula (I) described herein. Thus, the camptothecin moiety C can be linked to Y via a linker L. In formula (I), RBM, TIFF2024540692000086.tif6128, V, X, Y, R 1 , L, C, m, and n are as defined herein. The linker L serves to link Y to the camptothecin moiety (C). The linker L is any chemical moiety capable of linking Y to the camptothecin moiety C. In particular, the linker L connects Y to the camptothecin moiety C by a covalent bond. A linker reagent is a bifunctional or polyfunctional moiety that can be used to link the camptothecin moieties C and Y to form a conjugate of formula (I). The terms "linker reagent," "cross-linking reagent," "linker derived from a cross-linking reagent," and "linker" may be used interchangeably throughout this disclosure.

[0130] The linker is susceptible to cleavage, such as enzymatic cleavage, acid-induced cleavage, light-induced cleavage, and disulfide bond cleavage (cleavable linker). Enzymatic cleavage includes, but is not limited to, protease-induced cleavage, peptidase-induced cleavage, esterase-induced cleavage, glycosidase-induced cleavage, phosphatase-induced cleavage, and sulfatase-induced cleavage, preferably under conditions under which the camptothecin moiety and / or receptor-binding molecule remain active. Alternatively, the linker can be substantially resistant to cleavage (e.g., a stable linker or non-cleavable linker). In some aspects, the linker can be a procharged linker, a hydrophilic linker, a PEG-based linker, or a dicarboxylic acid-based linker. Thus, in some embodiments of any one of the antibody-drug conjugates disclosed herein, the linker (L) is selected from the group consisting of a cleavable linker, a non-cleavable linker, a hydrophilic linker, a PEG-based linker, a procharged linker, a peptidic linker, and a dicarboxylic acid-based linker. Preferably, the linker L is a cleavable linker. In some embodiments, the linker L is a non-cleavable linker.

[0131] Preferably, the linker L is cleavable as described herein. In some embodiments, L is a linker susceptible to enzymatic cleavage. In some embodiments, L is an acid-labile linker, a photolabile linker, a peptidase-cleavable linker, a protease-cleavable linker, an esterase-cleavable linker, a glycosidase-cleavable linker, a phosphatase-cleavable linker, a sulfatase-cleavable linker, a disulfide bond-reducing linker, a hydrophilic linker, a precharged linker, a PEG-based linker, or a dicarboxylic acid-based linker. Preferably, the linker L is cleavable by a protease, a glucuronidase, a sulfatase, a phosphatase, an esterase, or by disulfide reduction. Preferably, the linker is a peptidase-cleavable linker. Other preferred linkers are cleavable by a protease.

[0132] A non-cleavable linker is any chemical moiety that can link the camptothecin moiety to Y in a stable covalent manner and does not fall into the categories listed herein for cleavable linkers. Thus, a non-cleavable linker is substantially resistant to acid-induced cleavage, light-induced cleavage, peptidase-induced cleavage, protease-induced cleavage, glycosidase-induced cleavage, phosphatase-induced cleavage, esterase-induced cleavage, and disulfide bond cleavage. Furthermore, non-cleavability refers to the ability of the chemical bond within or adjacent to the linker to withstand cleavage induced by acids, photolabile cleaving agents, peptidases, proteases, glycosidases, phosphatases, esterases, or chemical or physiological compounds that cleave disulfide bonds under conditions that do not cause the camptothecin moiety or receptor-binding molecule to lose its activity.

[0133] An acid-labile linker is a linker that can be cleaved at an acidic pH. For example, certain intracellular compartments, such as endosomes and lysosomes, have an acidic pH (pH 4-5), providing suitable conditions for cleaving an acid-labile linker.

[0134] Some linkers can be cleaved by peptidases; i.e., peptidase-cleavable linkers. In this regard, certain peptides are readily cleaved intracellularly or extracellularly; see, for example, Trout et al., 79 Proc. Natl. Acad. Sci. USA, 626-629 (1982) and Umemoto et al., 43 Int. J. Cancer, 677-684 (1989). Peptides are composed of α-amino acids and peptide bonds, which are chemically amide bonds between the carboxylate of one amino acid and the amino group of another amino acid.

[0135] Some linkers can be cleaved by esterases; i.e., esterase-cleavable linkers. In this regard, certain esters can be cleaved by esterases present inside or outside of cells. Esters are formed by the condensation of a carboxylic acid with an alcohol. Simple esters are esters formed with simple alcohols, such as aliphatic alcohols, and small cyclic and small aromatic alcohols.

[0136] Procharged linkers are derived from charged cross-linking reagents that retain their charge after incorporation into an antibody drug conjugate. Examples of procharged linkers can be found in US 2009 / 0274713.

[0137] Preferably, the linker L is cleavable as described herein. As an illustrative example, the linker may be cleavable by a protease, glucuronidase, sulfatase, phosphatase, esterase, or by disulfide reduction. Preferably, the linker L is cleavable by a protease. More preferably, the linker is cleavable, particularly by a cathepsin, such as cathepsin B. The linker may include a dipeptide moiety, such as a valine-citrulline moiety or a valine-alanine moiety, that can be cleaved by a cathepsin, such as cathepsin B. Thus, in some embodiments, the linker includes a valine-citrulline moiety. In some embodiments, the linker includes a valine-alanine moiety. The linker may include a cleavage site. The term "cleavage site" may refer to a chemical moiety that is recognized by an enzyme and subsequently cleaved, for example, by hydrolysis. As an illustrative example, the cleavage site is a sequence of amino acids that is recognized by a protease or peptidase and hydrolyzed by said protease or peptidase. In some embodiments, the cleavage site is a dipeptide. In some embodiments, the cleavage site is a valine-citrulline moiety. In some embodiments, the cleavage site is a valine-alanine moiety.

[0138] Second spacer unit In a preferred embodiment, the linker (L) comprises a second spacer unit -A- bonded to -Y-. The second spacer unit serves to connect -Y- to another part of the linker (if present) or to the camptothecin moiety (-C). As will be readily understood by one of ordinary skill in the art, this depends on whether another part of the linker is present or not. The second spacer unit (-A-) can be any chemical group or moiety capable of linking -Y- to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present or not. In this regard, -Y- is bonded to the second spacer unit (-A-) as described herein. The second spacer unit (-A-) may include or be a functional group capable of forming a bond to another part of the linker (if present) or to the camptothecin moiety (-C). Again, this depends on whether another part of the linker is present or not. Preferably, the functional group capable of forming a bond to another part of the linker or to the camptothecin moiety (-C) is, for example, It is a carbonyl group depicted as TIFF2024540692000087.tif13128.

[0139] The second spacer unit can be any spacer known to those skilled in the art, for example, a straight-chain or branched-chain hydrocarbon-based moiety. The second spacer unit can also include a cyclic moiety, such as, but not limited to, an aromatic moiety. When the second spacer unit is a hydrocarbon-based moiety, the backbone of the second spacer moiety can contain only carbon atoms, but can also contain heteroatoms such as oxygen (O), nitrogen (N), or sulfur (S) atoms, and / or can contain a carbonyl group (C=O). The second spacer unit can be, for example, (C1-C 20 ) carbon atom chain, or (C-C 20) carbon atom chain. In typical embodiments of hydrocarbon-based second spacer units, the spacing moiety contains 1 to about 150, 1 to about 100, 1 to about 75, 1 to about 50, or 1 to about 40, or 1 to about 30, or 1 to about 20 (including 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and 19) backbone atoms. One of skill in the art would know how to select a suitable second spacer unit.

[0140] In some embodiments, the second spacer unit (-A-), if present, is *-(C-C 10 ) Alkylene-C(O)- # , *-(C3-C8)carbocyclo-C(O)- # , *-arylene-C(O)- # , *-(C1-C 10 ) Alkylene-arylene-C(O)- # , *-arylene-(C1-C 10 ) Alkylene-C(O)- # , *-(C1-C 10 )Alkylene-(C3-C8)carbocyclo-C(O)- # , *-(C3-C8)carbocyclo-(C1-C 10 ) Alkylene-C(O)- # , *-(C3-C8)heterocyclo-C(O)- # , *-(C1-C 10 ) alkylene-(C3-C8)heterocyclo-C(O)- # , and *-(C3-C8)heterocyclo-(C1-C 10 ) Alkylene-C(O)- # wherein * denotes the point of attachment to -Y-; and wherein # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Preferably, the second spacer unit (-A-), if present, is *-(C3-C8)carbocyclo-C(O)- # , *-arylene-C(O)- # , and *-(C3-C8)heterocyclo-C(O)- #* denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0141] In other embodiments, the second spacer unit (-A-), if present, is *-(C-C 10 ) alkylene- # , *-(C3-C8)carbocyclo- # , *-arylene- # , *-(C1-C 10 ) alkylene-arylene- # , *-arylene-(C1-C 10 ) alkylene- # , *-(C1-C 10 ) alkylene-(C3-C8) carbocyclo- # , *-(C3-C8)carbocyclo-(C1-C 10 ) alkylene- # , *-(C3-C8)heterocyclo- # , *-(C1-C 10 ) alkylene-(C3-C8)heterocyclo- # , and *-(C3-C8)heterocyclo-(C1-C 10 ) alkylene- # where * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Preferably, the second spacer unit (-A-), if present, is *-(C3-C8)carbocyclo- # , *-arylene- # , and *-(C3-C8)heterocyclo- # * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0142] Preferably, the second spacer unit -A- is TIFF2024540692000088.tif26128, where TIFF2024540692000089.tif20128 is a five- or six-membered carbocyclic ring; * indicates the point of attachment to -Y-; and # indicates the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. The carbocyclic ring can be aromatic or non-aromatic. Preferably, the second spacer unit -A- is TIFF2024540692000090.tif26128, where TIFF2024540692000091.tif19128 is a five- or six-membered heterocyclic ring containing 1, 2, or 3 heteroatoms independently selected from the group consisting of N, O, and S; * indicates the point of attachment to -Y-; and # indicates the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. The heterocyclic ring can be aromatic or non-aromatic.

[0143] More preferably, TIFF2024540692000092.tif26128 is TIFF2024540692000093.tif28128, wherein each of A, B, C, and D is independently selected from N (nitrogen) and CH; preferably, at least one of A, B, C, and D is CH; more preferably, at least two of A, B, C, and D are CH; even more preferably, at least three of A, B, C, and D are CH, and even more preferably, each of A, B, C, and D is CH; * indicates a point of attachment to -Y-; and # indicates a point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Even more preferably, TIFF2024540692000094.tif26128 is TIFF2024540692000095.tif28128, wherein each of A, B, C, and D is independently selected from N (nitrogen) and CH; preferably, at least one of A, B, C, and D is CH; more preferably, at least two of A, B, C, and D are CH; even more preferably, at least three of A, B, C, and D are CH, and even more preferably, each of A, B, C, and D is CH; wherein * indicates a point of attachment to -Y-; and # indicates a point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Even more preferably, TIFF2024540692000096.tif26128 is TIFF2024540692000097.tif25128, wherein each of A, B, C, and D is independently selected from N (nitrogen) and CH; preferably, at least one of A, B, C, and D is CH; more preferably, at least two of A, B, C, and D are CH; even more preferably, at least three of A, B, C, and D are CH, and even more preferably, each of A, B, C, and D is CH; where * indicates a point of attachment to -Y-; and # indicates a point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. In a highly preferred embodiment, the second spacer unit A is TIFF2024540692000098.tif25128, where * indicates the point of attachment to -Y-; and # indicates the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0144] In other embodiments, the second spacer unit (-A-) is TIFF2024540692000099.tif19128; and m and n are each independently an integer, e.g., from 0 to 20, from 0 to 15, from 1 to 10, from 1 to 8, from 1 to 6, from 1 to 4, from 1 to 3, from 1 to 2, or from 1, preferably m is 1 and n is 1; * indicates the position of -Y-, and # indicates the point of attachment, if present, to another part of the linker or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Such second spacer units may be substituted, e.g., one or two times with (C1-C8) alkyl, particularly at the carbon adjacent to the asterisk (*).

[0145] Base Z In a preferred embodiment, the second spacer unit -A- is a group Z, and the group Z has the following structure: TIFF2024540692000100.tif26128, where L P is the parallel connector unit; R S are each independently a second polyalkylene glycol unit; M is independently R s and L p is a bond or part that joins and; s* is an integer ranging from 1 to 4; and The wavy line indicates the point of attachment to -Y- and, depending on whether another part of the linker is present, to another part of the linker, if present, or to the camptothecin moiety (-C).

[0146] formula: As shown in TIFF2024540692000101.tif26128, the second polyalkylene glycol unit R S Parallel connector units L through suitable parts M P In some embodiments, M is a bond. In some embodiments, M connects the polyalkylene glycol unit to a parallel connector unit L PAs illustrative examples, M can be each independently -NH-, -O-, S, -C(O)-O-, -C(O)-NH-, and -(C-C 10 ) alkylene. Preferably, each M is independently selected from the group consisting of -NH-, -O-, and -S-. More preferably, each M is -O-.

[0147] The integer s* may range from 1 to 4. Preferably, the integer s* ranges from 1 to 3. More preferably, the integer s* is 1 or 2. Even more preferably, the integer s* is 1. The integer s* is the number of parallel connector units L P Group -MR connected to S Display the number of

[0148] Parallel connector unit (L P ) serves to connect -Y- to another part of the linker (L) and, via M, to one or more second polyalkylene glycol units, as indicated by the integer s*. Thus, when present, L P may be any chemical group or moiety that can connect -Y- to another part of the linker and, via M, to the second polyalkylene glycol unit. Alternatively, a parallel connector unit (L P ) can link Y to the camptothecin moiety (C), if no other parts of the linker are present, and to the second polyalkylene glycol unit via M. In this regard, Y can be linked to a parallel connector unit (L), as described herein. P ) are connected to the parallel connector unit (L P ) may contain or be a functional group capable of forming a bond to another part of the linker (L) or to the camptothecin moiety (C), depending on whether another part of the linker (L) is present. Preferably, the functional group capable of forming a bond to another part of the linker (L) or to the camptothecin moiety (-C) is, for example, TIFF2024540692000102.tif12128, or a carbonyl group depicted as -C(O)-, or -(C=O)-.

[0149] Parallel connector unit (L P ) can be, for example, a straight-chain or branched-chain hydrocarbon-based moiety. P ) can also include a ring portion. P When the parallel connector unit (L) is a hydrocarbon-based moiety, the backbone of the second spacer moiety may contain only carbon atoms, but may also contain heteroatoms such as oxygen (O), nitrogen (N) or sulfur (S) atoms, and / or may contain carbonyl groups (C=O). P ) is, for example, (C1-C 20 ) carbon atom chain, or (C-C 20 ) carbon atom chain. P In typical embodiments, the linking moiety contains 1 to about 150, 1 to about 100, 1 to about 75, 1 to about 50, or 1 to about 40, or 1 to about 30, or 1 to about 20 (including 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and 19) backbone atoms. P The second polyalkylene glycol unit R is connected via M. S Those skilled in the art will be able to easily connect to suitable parallel connector units (L P ) know what to choose.

[0150] In some embodiments, the group Z: TIFF2024540692000103.tif26128, when present, contains 1 to 4, preferably 1 to 3, more preferably 1 or 2, even more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) Alkylene-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR Sand each independently represents a substituted *-(C3-C8)carbocyclo-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently represents a substituted *-arylene-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) Alkylene-arylene-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently represents a substituted *-arylene-(C1-C 10 ) Alkylene-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C 10 )Alkylene-(C3-C8)carbocyclo-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)carbocyclo-(C1-C 10 ) Alkylene-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) alkylene-(C3-C8)heterocyclo-C(O)- # and 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo-(C1-C 10 ) Alkylene-C(O)- #wherein * denotes the point of attachment to -Y-; and wherein # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Preferably, the group Z: TIFF2024540692000104.tif26128, when present, contains 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently represents a substituted *-(C3-C8)carbocyclo-C(O)- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently represents a substituted *-arylene-C(O)- # and 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo-C(O)- # * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0151] In other embodiments, the group Z: TIFF2024540692000105.tif26128, when present, contains 1 to 4, preferably 1 to 3, more preferably 1 or 2, even more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) alkylene- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)carbocyclo- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently represents a substituted *-arylene- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C10 ) alkylene-arylene- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently represents a substituted *-arylene-(C1-C 10 ) alkylene- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) alkylene-(C3-C8) carbocyclo- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)carbocyclo-(C1-C 10 ) alkylene- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR S and each independently substituted *-(C1-C 10 ) alkylene-(C3-C8)heterocyclo- # and 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo-(C1-C 10 ) alkylene- # where * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Preferably, the group Z: TIFF2024540692000106.tif26128, when present, contains 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)carbocyclo- # 1 to 4, preferably 1 or 2, more preferably 1 group -MR Seach independently represents a substituted *-arylene- # and 1 to 4, preferably 1 or 2, more preferably 1 group -MR S each independently a substituted *-(C3-C8)heterocyclo- # * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0152] In some embodiments, the group Z: L in TIFF2024540692000107.tif26128 P can be one or more amino acids, which contain a suitable moiety M, so that a second polyalkylene glycol unit can be attached; preferably s* is 1. The amino acid can be a natural or unnatural amino acid. For example, the amino acid can be selected from the group consisting of lysine, glutamic acid, aspartic acid, serine, tyrosine, threonine, cysteine, selenocysteine, glycine, and homoalanine. In particular, the amino acid can be selected from the group consisting of tyrosine, serine, threonine, glutamic acid, lysine, and glycine. Other suitable moieties L P may be selected from the group consisting of amino alcohols, amino aldehydes, and polyamines. Suitable amino acids and further groups for connecting polyalkylene glycol units are described, for example, in WO 2015 / 057699.

[0153] Preferably, the group Z: TIFF2024540692000108.tif26128 is TIFF2024540692000109.tif34128, where TIFF2024540692000110.tif19128 is a five- or six-membered carbocyclic ring; the carbocyclic ring can be aromatic or non-aromatic; each M is independently as defined herein; preferably, each M is -O-; R Sare each independently a second polyalkylene glycol unit as defined herein; preferably, each R S is independently a second polyethylene glycol unit as defined herein; s* is an integer ranging from 1 to 3, preferably s* is 1 or 2, more preferably s* is 1; * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0154] More preferably, TIFF2024540692000111.tif34128 is TIFF2024540692000112.tif40165, wherein each of A, B, C, and D is CH; R S are each independently a second poly(alkylene) glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000113.tif14128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S * indicates the point of attachment to -Y-; and # indicates the attachment point to another part of the linker, if present (e.g., amino acid unit -W w Even more preferably, the point of attachment to the camptothecin moiety (-C) is indicated. TIFF2024540692000114.tif34128 is TIFF2024540692000115.tif37128, where each of A, B, C, and D is C-H; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000116.tif14128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. Even more preferably, TIFF2024540692000117.tif34128 is TIFF2024540692000118.tif34128, where each of A, B, C, and D is C-H; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000119.tif14128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S* denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. In a highly preferred embodiment, the group Z: TIFF2024540692000120.tif26128 is TIFF2024540692000121.tif27128, where R S is a second polyalkylene glycol unit as described herein; preferably, R S is a second polyethylene glycol unit as defined herein; M is as described herein; preferably M is -O-; * indicates the point of attachment to -Y-; and # indicates the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0155] In some embodiments, the group Z: TIFF2024540692000122.tif26128 is TIFF2024540692000123.tif36128, where TIFF2024540692000124.tif20128 is a five- or six-membered heterocyclic ring containing one or two heteroatoms independently selected from the group consisting of N, O, or S; the heterocyclic ring can be aromatic or non-aromatic; each M is independently as defined herein; preferably each M is -O-; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R Sis independently a second polyethylene glycol unit as defined herein; s* is 1 or 2 (particularly in the case of a six-membered heterocyclic ring), preferably s* is 1 (particularly in the case of a five- or six-membered heterocyclic ring); * indicates the point of attachment to -Y-; and # indicates the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0156] In some embodiments, TIFF2024540692000125.tif37128 is TIFF2024540692000126.tif39164, wherein three of A, B, C, and D are independently CH, and one of A, B, C, and D is independently N; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000127.tif14128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. TIFF2024540692000128.tif35128 is TIFF2024540692000129.tif37128, wherein three of A, B, C, and D are independently CH, and one of A, B, C, and D is independently N; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000130.tif14128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. TIFF2024540692000131.tif36128 is TIFF2024540692000132.tif34128, wherein three of A, B, C, and D are independently CH, and one of A, B, C, and D is independently N; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000133.tif15128, when s* is 2, H is -MR independently in two CHs. Sor if s* is 1, in one CH, H is -MR S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0157] In some embodiments, TIFF2024540692000134.tif35128 is TIFF2024540692000135.tif39166, wherein two of A, B, C, and D are independently CH and two of A, B, C, and D are independently N; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000136.tif15128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is replaced by R S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. TIFF2024540692000137.tif35128 is TIFF2024540692000138.tif37128, wherein two of A, B, C, and D are independently CH, and two of A, B, C, and D are independently N; R Sare each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000139.tif15128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S * denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present. TIFF2024540692000140.tif35128 is TIFF2024540692000141.tif34128, wherein two of A, B, C, and D are independently CH, and two of A, B, C, and D are independently N; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; the integer s* is 1 or 2, preferably s* is 1; As shown in TIFF2024540692000142.tif15128, when s* is 2, H is -MR independently in two CHs. S or if s* is 1, in one CH, H is -MR S* denotes the point of attachment to -Y-; and # denotes the point of attachment to another part of the linker, if present, or to the camptothecin moiety (-C), depending on whether another part of the linker is present.

[0158] second polyalkylene glycol unit R S The term "second polyalkylene glycol unit" as used herein refers to a parallel connector unit (L P ) The second polyalkylene glycol unit comprises at least one alkylene glycol subunit. Preferably, the second polyalkylene glycol unit R S has the following structure: More preferably, the second polyalkylene glycol unit R S has the following structure: TIFF2024540692000144.tif15128. Thus, the second polyalkylene glycol unit R S may be a poly(tetramethylene glycol) unit, a poly(propylene glycol) unit, or a poly(ethylene glycol) unit. Even more preferably, the second polyalkylene glycol unit has the following structure: TIFF2024540692000145.tif14128 and contains one or more alkylene glycol subunits.

[0159] Preferably, the second polyalkylene glycol unit R S each independently comprises 1 to 100 alkylene glycol subunits as described herein. More preferably, the second polyalklyene glycol unit R Seach independently comprises 2 to 50 alkylene glycol subunits. Even more preferably, the second polyalkylene glycol units each independently comprise 3 to 45 alkylene glycol subunits as described herein. Even more preferably, the second polyalkylene glycol units each independently comprise 4 to 40 alkylene glycol subunits as described herein. Even more preferably, the second polyalkylene glycol units each independently comprise 6 to 35 alkylene glycol subunits as described herein. Even more preferably, the second polyalkylene glycol units each independently comprise 8 to 30 alkylene glycol subunits as described herein.

[0160] Preferably, the second polyalkylene glycol unit R S each independently comprises 1 to 20 alkylene glycol subunits as described herein. More preferably, the second polyalkylene glycol units R S each independently comprises 2 to 12 alkylene glycol subunits. Even more preferably, the second polyalkylene glycol units each independently comprise 3 to 11 alkylene glycol subunits as described herein.

[0161] second polyalkylene glycol unit R S are each independently of the structure: TIFF2024540692000146.tif15128, and may be a polyalkylene glycol unit containing 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits having the same structure. Preferably, the second polyalkylene glycol unit R S are each independently of the structure: TIFF2024540692000147.tif15128, 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits. More preferably, the second polyalkylene glycol unit R S are each independently of the structure: In a highly preferred embodiment, the second polyalkylene glycol unit R S are each independently of the structure: It may be a polyethylene glycol unit containing 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits having the formula TIFF2024540692000149.tif10128.

[0162] second polyalkylene glycol unit R S are each independently of the structure: The second polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000150.tif15128. Preferably, the second polyalkylene glycol unit R S are each independently of the structure: The second polyalkylene glycol unit R may be a polyalkylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000151.tif15128. S are each independently of the structure: In a highly preferred embodiment, the second polyalkylene glycol unit R S are each independently of the structure: It may be a polyethylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000153.tif10128.

[0163] Preferably, the second polyalkylene glycol unit R S are each independently TIFF2024540692000154.tif16128, where: TIFF2024540692000155.tif10128 indicates the position of M in group Z; K S is H or a second capping group; preferably, K S are -H (hydrogen), -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 ) alkyl-N((C1-C3) alkyl)2; more preferably K S is H; and p is an integer ranging from 1 to 100.

[0164] A "second capping group," as referred to herein, can be any moiety that can function as the terminal group of a second polyalkylene glycol unit. Examples of second capping groups that can be used in the present disclosure include -POH, -(C-C 10) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 In some embodiments, the first capping group is -(C-C) alkyl-N((C-C) alkyl). 10 ) alkyl, especially methyl.

[0165] Preferably, K S is H (hydrogen).

[0166] The integer p is the repeating unit in the second polyalkylene glycol unit: TIFF2024540692000156.tif12128 displays the number. The integer p can be in the range of 1 to 100. Preferably, p is in the range of 2 to 50. More preferably, p is in the range of 3 to 45. More preferably, p is in the range of 4 to 40. Even more preferably, p is in the range of 6 to 35. Even more preferably, p is in the range of 8 to 30. In a preferred embodiment, p is 12 or about 12. Even more preferably, p is in the range of 16 to 30. Even more preferably, p is in the range of 20 to 28. Even more preferably, p is 22, 23, 24, 25, or 26. Even more preferably, p is 23, 24, or 25. In a preferred embodiment, p is 24 or about 24. Preferably, the repeating unit is TIFF2024540692000157.tif11128. More preferably, the repeating unit is TIFF2024540692000158.tif12128.

[0167] In the second polyalkylene glycol unit, the integer p can range from 1 to 20. Preferably, p ranges from 2 to 12. More preferably, p ranges from 3 to 11. Preferably, the repeating unit is TIFF2024540692000159.tif11128. More preferably, the repeating unit is The file is TIFF2024540692000160.tif12128.

[0168] Preferably, the second polyalkylene glycol unit R S has the following structure: TIFF2024540692000161.tif10128, i.e., the subunit is designated as an "ethylene glycol subunit." Thus, preferably, the second polyalkylene glycol unit is a second polyethylene glycol unit. The second polyethylene glycol unit includes at least one ethylene glycol subunit.

[0169] Preferably, the second polyalkylene glycol unit R S are each independently of the structure: The second polyethylene glycol unit may include 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 subunits having the formula TIFF2024540692000162.tif9128.

[0170] Preferably, the second polyalkylene glycol unit R S are each independently of the structure: The second polyethylene glycol unit may be a second polyethylene glycol unit containing 1 to 20, preferably 2 to 12, more preferably 3 to 11 subunits having the formula TIFF2024540692000163.tif9128.

[0171] Preferably, the second polyalkylene glycol unit R S are each independently of the structure: a second polyethylene glycol unit having TIFF2024540692000164.tif15128; where: TIFF2024540692000165.tif10128 indicates the position of M in group Z; K S is H (hydrogen) or a second capping group as described herein; preferably, K S are -H (hydrogen), -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10 ) alkyl-N((C1-C3) alkyl)2; more preferably K S is H; and p is an integer ranging from 1 to 100.

[0172] The integer p is the repeating unit in the second polyethylene glycol unit: TIFF2024540692000166.tif12128 displays the number. The integer p can be in the range of 1 to 100. Preferably, p is in the range of 2 to 50. More preferably, p is in the range of 3 to 45. Even more preferably, p is in the range of 4 to 40. Even more preferably, p is in the range of 6 to 35. Even more preferably, p is in the range of 8 to 30. In a preferred embodiment, p is 12 or about 12. Even more preferably, p is in the range of 16 to 30. Even more preferably, p is in the range of 20 to 28. Even more preferably, p is 22, 23, 24, 25, or 26. Even more preferably, p is 23, 24, or 25. In a preferred embodiment, p is 24 or about 24.

[0173] In the second polyethylene glycol unit, the integer p can be in the range of 1 to 20. Preferably, p is in the range of 2 to 12. More preferably, p is in the range of 3 to 11.

[0174] Generally, the second polyalkylene glycol unit R F In the (preferably second polyethylene glycol unit), polydisperse polyalkylene glycols (preferably polydisperse polyethylene glycols), monodisperse polyalkylene glycols (preferably monodisperse polyethylene glycols), and individual polyalkylene glycols (preferably individual polyethylene glycols) can be used. Polydisperse polyalkylene glycols (preferably polydisperse polyethylene glycols) are heterogeneous mixtures of sizes and molecular weights, whereas monodisperse polyalkylene glycols (preferably monodisperse polyethylene glycols) are typically purified from heterogeneous mixtures and thus provide a single chain length and molecular weight. Preferred second polyalkylene glycol units are individual polyalkylene glycols (preferably individual polyethylene glycols), i.e., compounds that are synthesized stepwise rather than by a polymerization process. Individual polyalkylene glycols (preferably individual polyethylene glycols) provide single molecules with defined and specified chain lengths.

[0175] The second polyalkylene glycol unit (preferably, the second polyethylene glycol unit) provided herein comprises one or more polyalkylene glycol chains (preferably, polyethylene glycol chains). The polyalkylene glycol chains (preferably, polyethylene glycol chains) can be linked together, for example, in a linear, branched, or star configuration. Optionally, at least one of the polyalkylene glycol chains (preferably, polyethylene glycol chains) can be derivatized at one end for covalent attachment to M in the group Z.

[0176] The second polyalkylene glycol unit (preferably, the second polyethylene glycol unit) is connected to the conjugate (or an intermediate thereof) at M in group Z. The other end(s) of the second polyalkylene glycol unit (preferably, the second polyethylene glycol unit) is free and untethered and may take the form of a hydrogen, methoxy, carboxylic acid, alcohol, or other suitable functional group, such as, for example, any second capping group as described herein. The methoxy, carboxylic acid, alcohol, or other suitable functional group acts as a cap for the terminal polyalkylene glycol subunit (preferably, the polyethylene glycol subunit) of the second polyalkylene glycol unit (preferably, the second polyethylene glycol unit). By untethered, it is meant that the second polyalkylene glycol unit (preferably, the second polyethylene glycol unit) is not connected at its untethered position to the camptothecin moiety (C), to the receptor-binding molecule, or to a component of the linker (L) linking the camptothecin moiety and / or the receptor-binding molecule. For embodiments in which the second polyalkylene glycol unit (preferably, the second polyethylene glycol unit) comprises more than one polyalkylene glycol chain (preferably, a polyethylene glycol chain), the multiple polyalkylene glycol chains (preferably, the polyethylene glycol chains) may be the same or different chemical moieties (e.g., polyalkylene glycols, particularly polyethylene glycols, of different molecular weights or subunit numbers). The multiple second polyalkylene glycol chains (preferably, the second polyethylene glycol chains) are connected to M in group Z at a single connection site. One skilled in the art will understand that the second polyalkylene glycol unit (preferably, the second polyethylene glycol unit), in addition to comprising repeating polyalkylene glycol subunits (preferably, polyethylene glycol subunits), may further contain a non-polyalkylene glycol material (preferably, a non-polyethylene glycol material) (e.g., to facilitate coupling of the multiple polyalkylene glycol chains (preferably, the polyethylene glycol chains) to each other or to M in group Z).A non-polyalkylene glycol material (preferably a non-polyethylene glycol material) refers to an atom in a second polyalkylene glycol unit (preferably a second polyethylene glycol unit) that is not part of a repeating alkylene glycol subunit (preferably, a -CHCHO- subunit). In embodiments provided herein, the second polyalkylene glycol unit (preferably, a second polyethylene glycol unit) can comprise two monomeric polyalkylene glycol chains (preferably, polyethylene glycol chains) linked to each other via a non-polyalkylene glycol (preferably, non-polyethylene glycol) element. In other embodiments provided herein, the second polyalkylene glycol unit (preferably, a second polyethylene glycol unit) can comprise two linear polyalkylene glycol chains (preferably, polyethylene glycol chains) connected to a central core that is connected to M in group Z (i.e., the polyalkylene glycol unit (preferably, the polyethylene glycol unit) is branched).

[0177] There are numerous methods for attaching polyalkylene glycols (preferably polyethylene glycols) available to those skilled in the art [see, e.g., EP 0 401 384 (PEG coupling to G-CSF); U.S. Pat. No. 5,757,078 (PEGylation of EPO peptides); U.S. Pat. No. 5,672,662 (Polyethylene glycols monosubstituted with propionic or butanoic acid and their functional derivatives for biotechnological applications) and related polymers; U.S. Pat. No. 6,077,939 (PEGylation of the N-terminal α-carbon of peptides); and Veronese (2001) Biomaterials 22:405-417 (review on peptide and protein PEGylation)].

[0178] For example, polyalkylene glycol (preferably polyethylene glycol) can be covalently attached to an amino acid residue via a reactive group. The reactive group is one (e.g., a free amino or carboxyl group) to which an activated polyalkylene glycol molecule (preferably a polyethylene glycol molecule) can be attached. For example, the N-terminal amino acid residue and lysine (K) residue have a free amino group; the C-terminal amino acid residue has a free carboxyl group. Sulfhydryl groups (e.g., those found in cysteine ​​residues) can also be used as reactive groups to attach polyalkylene glycol (preferably polyethylene glycol). Additionally, enzyme-assisted methods for specifically introducing activating groups (e.g., hydrazides, aldehydes, and aromatic amino groups) into the C-terminus of polypeptides have been described (see Schwarz, et al. (1990) Methods Enzymol. 184:160; Rose, et al. (1991) Bioconjugate Chem. 2: 154; and Gaertner, et al. (1994) J. Biol. Chem. 269:7224).

[0179] In some embodiments, at least one of the polyalkylene glycol chains (preferably polyethylene glycol chains) making up the second polyalkylene glycol unit (preferably the second polyethylene glycol unit) may be functionalized so that it can be coupled to M in group Z, or to a parallel connector unit L in group Z when M is a bond. P can be connected to. Functionalization can be achieved, for example, by amine, thiol, NHS ester, alkyne, azide, carbonyl, or other functional groups. The polyalkylene glycol unit (preferably a polyethylene glycol unit) can further comprise a non-polyalkylene glycol material (preferably a non-polyethylene glycol material, i.e., a material not composed of -CHCHO-) to facilitate coupling to M in group Z or to a parallel connector unit (when M is a bond), or to facilitate coupling of two or more polyalkylene glycol chains (preferably polyethylene glycol chains).

[0180] In preferred embodiments, the second polyalkylene glycol unit, more preferably the second polyethylene glycol unit, is directly connected to M in group Z. In these embodiments, the second polyalkylene glycol unit, preferably the second polyethylene glycol unit, does not include a functional group for connection to M in group Z, i.e., M is bonded directly to a carbon atom of the second polyalkylene glycol unit, more preferably to CH2 of the second polyethylene glycol unit. Preferably, in any one of these embodiments, M is not a bond.

[0181] In one group of embodiments, the second polyalkylene glycol unit comprises at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three alkylene glycol subunits, even more preferably at least four alkylene glycol subunits, even more preferably at least six alkylene glycol subunits, and even more preferably at least eight alkylene glycol subunits. In some such embodiments, the second polyalkylene glycol unit comprises no more than about 100 alkylene glycol subunits, preferably no more than about 50 alkylene glycol subunits, more preferably no more than about 45 alkylene glycol subunits, more preferably no more than about 40 alkylene glycol subunits, more preferably no more than about 35 subunits, and even more preferably no more than about 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunit can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000167.tif9128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit.

[0182] In one group of embodiments, the second polyalkylene glycol unit comprises one or more linear polyalkylene glycol chains each having at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three alkylene glycol subunits, even more preferably at least four alkylene glycol subunits, even more preferably at least six alkylene glycol subunits, and even more preferably at least eight alkylene glycol subunits. In preferred embodiments, the second polyalkylene glycol unit comprises a total of at least one alkylene glycol subunit, preferably at least two alkylene glycol subunits, more preferably at least three, even more preferably at least four, even more preferably at least six, or even more preferably at least eight alkylene glycol subunits. In some such embodiments, the second polyalkylene glycol unit comprises a total of about 100 or less alkylene glycol subunits, preferably a total of about 50 or less alkylene glycol subunits, more preferably a total of about 45 or less subunits, even more preferably a total of about 40 or less subunits, even more preferably a total of about 35 or less subunits, and even more preferably a total of about 30 or less subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000168.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit comprising one or more linear polyethylene glycol chains.

[0183] In another group of embodiments, the second polyalkylene glycol unit comprises a total of 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000169.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit.

[0184] In another group of embodiments, the second polyalkylene glycol unit comprises one or more linear polyalkylene glycol chains having a total of 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000170.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit comprising one or more linear polyethylene glycol chains.

[0185] In another group of embodiments, the second polyalkylene glycol unit is a linear single polyalkylene glycol chain having at least one subunit, preferably at least two subunits, more preferably at least three subunits, even more preferably at least six subunits, and even more preferably at least eight subunits. In any one of these embodiments, the alkylene glycol subunit can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000171.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit that is a linear single polyethylene glycol chain. Optionally, in any one of these embodiments, the linear single polyalkylene glycol chain can be derivatized.

[0186] In another group of embodiments, the second polyalkylene glycol unit is a linear single polyalkylene glycol chain having 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, more preferably 6 to 35, and more preferably 8 to 30 alkylene glycol subunits. In any one of these embodiments, the alkylene glycol subunits can be any alkylene glycol subunit as described herein. Preferably, in any one of these embodiments, each alkylene glycol subunit has the following structure: TIFF2024540692000172.tif10128. Preferably, when each alkylene glycol subunit is an ethylene glycol subunit, in any one of these embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit that is a linear single polyethylene glycol chain. Optionally, in any one of these embodiments, the linear single polyalkylene glycol chain can be derivatized.

[0187] In any one of the embodiments provided herein, an exemplary linear polyethylene glycol unit that can be used as the second polyalkylene glycol unit, and particularly as the second polyethylene glycol unit, is as follows: TIFF2024540692000173.tif40128 where the wavy line indicates the site of attachment to M in group Z; R 20 is a PEG-linking unit; preferably, R 20 is absent; more preferably, M is not a bond; R 21 is a PEG capping unit (referred to herein as R 21 is "K S " also appears); R 22 is a PEG coupling unit (i.e., for coupling multiple PEG subunit chains together); n is independently selected from 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30; e is 2 to 5; Each n' is independently selected from 1 to 100, preferably 2 to 50, more preferably 3 to 45, more preferably 4 to 40, even more preferably 6 to 35, and even more preferably 8 to 30. In preferred embodiments, there is at least 1, preferably at least 2, more preferably at least 3, more preferably at least 4, more preferably at least 6, and even more preferably at least 8 ethylene glycol subunits in the polyethylene glycol unit. In some embodiments, there are 100 or fewer, preferably 50 or fewer, more preferably 45 or fewer, more preferably 40 or fewer, more preferably 35 or fewer, and even more preferably 30 or fewer ethylene glycol subunits in the polyethylene glycol unit. R 20 is absent, the (CH2CH2O) subunit is directly bonded to M in group Z; more preferably, in such embodiments, M is not a bond.

[0188] Preferably, the linear polyethylene glycol unit is TIFF2024540692000174.tif9128, where the wavy line indicates the site of attachment to M in group Z; R 20 , R 21 (referred to herein as "K S ") and n are as defined herein; more preferably R 20 is absent; even more preferably, M is not a bond. In preferred embodiments, n is 12 or about 12. In preferred embodiments, n is 24 or about 24. Preferably, R 21 is H.

[0189] Polyethylene glycol connecting unit R 20When present, M is part of the second polyethylene glycol unit and acts to link the second polyethylene glycol unit to M. In these embodiments, preferably M is not a bond but forms a bond with the second polyethylene glycol unit. In exemplary embodiments, the PEG connecting unit R 20 If present, *-C(O)- # , *-S(O)- # , *-C(O)O- # , *-C(O)-(C1-C 10 ) Alkyl- # , *-C(O)-(C1-C 10 )Alkyl-O- # , *-C(O)-(C1-C 10 )Alkyl-CO2- # , *-C(O)-(C1-C 10 )Alkyl-NH- # , *-C(O)-(C1-C 10 )Alkyl-S- # ;*-C(O)-(C1-C 10 )Alkyl-C(O)-NH- # ;*-C(O)-(C1-C 10 )Alkyl-NH-C(O)- # ;-(C1-C 10 ) Alkyl- # , *-(C1-C 10 )Alkyl-O- # , *-(C1-C 10 )Alkyl-C(O)- # , *-(C1-C 10 )Alkyl-C(O)O- # , *-(C1-C 10 )Alkyl-NH- # , *-(C1-C 10 )Alkyl-S- # , *-(C1-C 10 )Alkyl-C(O)-NH- # , *-(C1-C 10 )Alkyl-NH-C(O)- # , and *-CH2-CH2SO2-(C1-C 10 ) Alkyl- # , *-CH2-C(O)-(C1-C 10 ) Alkyl-# wherein * denotes the point of attachment to M in Z, and # denotes the point of attachment to the ethylene glycol unit.

[0190] PEG coupling unit R 22 When present, is part of the second polyethylene glycol unit and is a non-PEG material that acts to link two or more chains of repeating -CHCHO- subunits. In an exemplary embodiment, the PEG coupling unit R 22 If present, *-(C1-C 10 )Alkyl-C(O)-NH- # , *-(C1-C 10 )Alkyl-NH-C(O)- # , *-(C2-C 10 )Alkyl-NH- # , *-(C2-C 10 )Alkyl-O- # , *-(C1-C 10 )Alkyl-S- # , or *-(C2-C 10 )Alkyl-NH- # where * denotes the point of attachment to the oxygen atom of an ethylene glycol subunit, and # denotes the point of attachment to a carbon atom of another ethylene glycol subunit.

[0191] As used herein, "K S ", also displayed as the group R 21 is H (hydrogen) in exemplary embodiments, or may be a second capping group, as described herein; preferably, R 21 -H, -PO3H, -(C1-C 10 ) alkyl, -(C1-C 10 ) alkyl-SO3H, -(C2-C 10 ) alkyl-CO2H, -(C2-C 10 ) alkyl-OH, -(C2-C 10 ) alkyl-NH2, -(C2-C 10 ) alkyl-NH(C1-C3) alkyl and -(C2-C 10In some embodiments, R21 is independently selected from the group consisting of -(C1-C3)alkyl-N((C1-C3)alkyl). 10 ) alkyl, especially methyl. More preferably R 21 is H.

[0192] In any one of the embodiments provided herein, an illustrative linear second polyethylene glycol unit that can be used as the second polyalkylene glycol unit is as follows: TIFF2024540692000175.tif81128 where the wavy line indicates the site of attachment to M in group Z; preferably, M is not a bond; and each n is 1 to 100, preferably 2 to 50, more preferably 3 to 45, even more preferably 4 to 40, even more preferably 6 to 35, and still more preferably 8 to 30. In some embodiments, n is about 12. In some embodiments, n is about 24.

[0193] In some embodiments, the second polyalkylene glycol unit is about 300 daltons to about 5 kilodaltons; about 300 daltons to about 4 kilodaltons; about 300 daltons to about 3 kilodaltons; about 300 daltons to about 2 kilodaltons; or about 300 daltons to about 1 kilodalton. In some such aspects, the second polyalkylene glycol unit has at least 6 alkylene glycol subunits or at least 8 alkylene glycol subunits. In some such aspects, the second polyalkylene glycol unit may have at least 6 alkylene glycol subunits or at least 8 alkylene glycol subunits, but not more than 100 alkylene glycol subunits, preferably not more than 50 alkylene glycol subunits. In some embodiments, the second polyalkylene glycol unit is a second polyethylene glycol unit that is about 300 daltons to about 5 kilodaltons; about 300 daltons to about 4 kilodaltons; about 300 daltons to about 3 kilodaltons; about 300 daltons to about 2 kilodaltons; or about 300 daltons to about 1 kilodalton. In some such aspects, the second polyethylene glycol unit can have at least 6 ethylene glycol subunits or at least 8 ethylene glycol subunits. In some such aspects, the second polyethylene glycol unit can have at least 6 ethylene glycol subunits or at least 8 ethylene glycol subunits, but not more than 100 ethylene glycol subunits, preferably not more than 50 ethylene glycol subunits.

[0194] In some embodiments, the second polyalkylene glycol unit R S is present, no other alkylene glycol subunits are present in the conjugate of formula (I) (i.e., the alkylene glycol subunits are not represented by groups R, e.g., as provided herein). 1 or in another part of the linker L, is not present in any of the other components of the conjugate). In another aspect, the second polyalkylene glycol unit R Sis present, then no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 other alkylene glycol subunits are present in the conjugate of formula (I) (i.e., no more than 8, 7, 6, 5, 4, 3, 2, or 1 other alkylene glycol subunits are present in the conjugate of formula (I)). 1 or in another component of the conjugate, such as in another part of the linker L).

[0195] Preferably, in another embodiment, the second polyalkylene glycol unit R S When R is present, the conjugate may be a substituted or unsubstituted aryl group, as described herein. 1 the first polyalkylene glycol unit R F Preferably, R S is the second polyethylene glycol unit, and the conjugate is the first polyalkylene glycol unit R F When the first polyalkylene glycol unit further comprises a first polyethylene glycol unit, as described herein.

[0196] It will be understood that when referring to alkylene glycol subunits, particularly ethylene glycol subunits, and depending on the context, the number of subunits may represent an average number, for example, when referring to a population of conjugates or intermediate compounds and using polydisperse polyalkylene glycols, particularly polydisperse polyethylene glycols.

[0197] Linker*-A a -W w -B b - ## In some embodiments, the linker L has the formula: a -W w -B b - ##wherein: -A- is a second spacer unit, as described herein; a is 0 or 1; each -W- is independently an amino acid; w is independently an integer ranging from 0 to 12; -B- is a first spacer unit; and b is 0 or 1; * indicates the point of attachment to -Y-; and ## indicates the point of attachment to the camptothecin moiety. As used herein, the notation "W w " or "W w -", etc., i.e., the combination of W and the associated integer w is also designated as an "amino acid unit". Examples of suitable second spacer units, amino acid units and first spacer units are described, for example, in WO 2004 / 010957 A2.

[0198] Structure*-A a -W w -B b - ## In a linker having the formula: w -. The second spacer unit (-A-) can be any second spacer unit as described herein. When present, the second spacer unit (-A-) can be any chemical group or moiety capable of linking -Y- to an amino acid unit. Alternatively, the second spacer unit can link -Y- to the first spacer unit if the amino acid unit is not present. Alternatively, the second spacer unit can link -Y- to the camptothecin moiety (-C) if the first spacer unit and the amino acid unit are not present. In this regard, -Y- is attached to the second spacer unit (-A-) as described herein. The second spacer unit (-A-) can link -Y- to the amino acid unit (-W). w -) and / or the first spacer unit (-B-) are present, w Preferably, the amino acid unit (-W) may comprise or be a functional group capable of forming a bond to the first spacer unit (-B-) or to the camptothecin moiety (-C). wFunctional groups capable of forming a bond to the first spacer unit (-B-), in particular to the N-terminus of the amino acid unit, or to the first spacer unit (-B-) or to the camptothecin moiety (-C) are, for example: TIFF2024540692000176.tif11128 or a carbonyl group depicted as -C(O)-. The integer a associated with the second spacer unit can be 0 or 1. Preferably, the integer a is 1. Alternatively, in other embodiments, the second spacer unit is absent (a = 0).

[0199] Linker*-A a -W w -B b - ## In the formula (I), the second spacer unit -A-, when present, can be any second spacer unit as described herein. a -W w -B b - ## In a preferred embodiment, the second spacer unit -A-, if present (a=1), has the structure: TIFF2024540692000177.tif26128, wherein TIFF2024540692000178.tif26128 is as defined herein. Thus, in a preferred embodiment, the linker (L) has the structure: TIFF2024540692000179.tif29128, where L P , R S , s*, M, W, w, B and b are as defined herein; * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0200] Amino acid unit (-W wThe -), when present, may link the second spacer unit A to the first spacer unit B if the first spacer unit is present. Alternatively, the amino acid unit may link the second spacer unit to the camptothecin moiety (C) if the first spacer unit is not present. Alternatively, the amino acid unit may link Y to the first spacer unit if the second spacer unit is not present. Alternatively, the amino acid unit may link Y to the camptothecin moiety if the first spacer unit and second spacer unit are not present.

[0201] Amino Acid Unit-W w - can be a dipeptide (w = 2), tripeptide (w = 3), tetrapeptide (w = 4), pentapeptide (w = 5), hexapeptide (w = 6), heptapeptide (w = 7), octapeptide (w = 8), nonapeptide (w = 9), decapeptide (w = 10), undecapeptide (w = 11) or dodecapeptide (w = 12).

[0202] In some embodiments, the amino acid unit can comprise a naturally occurring amino acid. In some embodiments, the amino acid unit can comprise a non-naturally occurring amino acid.

[0203] In any one of the embodiments described herein, each amino acid of the amino acid unit can independently be in the L-configuration or the D-configuration, except for non-chiral amino acids such as, for example, glycine. Preferably, in any one of the embodiments described herein, each amino acid of the amino acid unit is in the L-configuration (i.e., the naturally occurring configuration), except for non-chiral amino acids such as, for example, glycine.

[0204] Preferably, when a second spacer unit (-A-) is present, the amino acid unit -W w The N-terminus of - is more preferably attached to the second spacer unit (A) via a carbonyl group of the second spacer unit. Preferably, in any one of the embodiments described herein, the amino acid unit -Ww The C-terminus of - is attached to the first spacer unit (B), if present. Alternatively, in any one of the embodiments described herein, the amino acid unit -W w The C-terminus of - can be attached to the camptothecin moiety (-C) when the first spacer unit is absent. w The N-terminus of - may be attached to the first spacer unit (B), if present, and the C-terminus may be attached to the second spacer unit A, if present.

[0205] In some embodiments, w can be 1 or 2. Preferably, the amino acid unit W w is a dipeptide (w=2). In a dipeptide, each amino acid may independently have the formula shown below in square brackets: TIFF2024540692000180.tif28128 where, R 19 is hydrogen, methyl, isopropyl, isobutyl, sec-butyl, benzyl, p-hydroxybenzyl, -CH2OH, -CH(OH)CH3, -CH2CH2SCH3, -CH2CONH2, -CH2COOH, -CH2CH2CONH2, -CH2CH2COOH, -(CH2)3NHC(=NH)NH2, -(CH2)3NH2, -(CH2)3NHCOCH3, -(CH2)3NHCHO, -(CH2)4NHC(=NH)NH2, -(CH2)4NH2, -(CH2)4NHCOCH3, -(CH2)4NHCHO, -(CH2)3NHCONH2, -(CH2)4NHCONH2, -CH2CH2CH(OH)CH2NH2, 2-pyridylmethyl-, 3-pyridylmethyl-, 4-pyridylmethyl-, phenyl, cyclohexyl, The file is TIFF2024540692000181.tif95147.

[0206] The amino acid unit can be enzymatically cleaved by one or more enzymes, including but not limited to, a tumor-associated protease, preferably a cathepsin, more preferably cathepsin B, to liberate the camptothecin moiety (-C), which, in one embodiment, is protonated in vivo upon release to provide the free camptothecin moiety (C). w The - unit is represented by formula (VII).

[0207] Therefore, -W w The -unit may be a dipeptide of formula (VII): TIFF2024540692000182.tif23128 in formula, R 20 and R 21 is as follows: TIFF2024540692000183.tif64128.

[0208] Exemplary amino acid units include R 20 is benzyl and R 21 is -(CH2)4NH2 (Phe-Lys); R 20 is isopropyl and R 21 is -(CH2)4NH2 (Val-Lys); R 20 is isopropyl and R 21 is —(CH 2 ) 3 NHCONH 2 (Val-Cit), a unit of formula (VII).

[0209] Useful -W w The -W units can be designed and optimized in their selectivity for enzymatic cleavage by specific enzymes, such as tumor-associated proteases. w The -W unit is one whose cleavage is catalyzed by cathepsin B, C and / or D, or plasmin proteases ("tumor-associated proteases"). w-unit is cleaved by cathepsin B. Suitable linkers that can be cleaved by proteases are described, for example, in GM Dubowchik et al., "Cathepsin B-Labile Dipeptide Linkers for Lysosomal Release of Doxorubicin from Internalizing Immunoconjugates; Model Studies of Enzymatic Drug Release and Antigen-Specific In Vitro Anticancer Activity," Bioconjugate Chem., Vol. 13, No. 4, 2002, 855-869; SC Jeffrey et al., "Dipeptide-based highly potent doxorubicin antibody conjugate," Bioorg. Med. Chem. Lett. 16 (2006), 358-362; and MS Kung Sutherland et al., "SGN-CD33A: a novel CD33-targeting antibody-drug conjugate using a pyrrolobenzodiazepine dimer is active in models of drug-resistant AML," Blood, 22 August 2013, volume 1. 122, number 8, 1455-1463.

[0210] R 19 , R 20 , or R 21 If is other than hydrogen, R 19 , R 20 , or R 21 The carbon atom to which R is attached is chiral. 19 , R 20 , or R 21 Each carbon atom to which R is attached may independently be in the (S) or (R) configuration. 19 , R 20 , or R 21Each carbon atom to which is attached, if chiral, is in the (S) configuration.

[0211] In one preferred embodiment, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). In another preferred embodiment, the amino acid unit is valine-alanine (i.e., Val-Ala or VA). In another preferred embodiment, the amino acid unit is alanine-alanine (i.e., Ala-Ala or AA). In another preferred embodiment, the amino acid unit is phenylalanine-lysine (i.e., Phe-Lys or FK). Such linkers are illustrative examples of linkers that can be cleaved by a protease, such as cathepsin B.

[0212] The designations of peptides used throughout the specification follow conventional nomenclature. Thus, the N-terminus of the peptide is written on the left and the C-terminus of the peptide is written on the right. As an illustrative, but non-limiting, example, in the dipeptide valine-citrulline (i.e., Val-Cit or VC), valine is at the N-terminus and citrulline is at the C-terminus. Preferably, in any one of the embodiments described herein, if a second spacer unit (-A-) is present, the N-terminus of the peptide, such as a dipeptide (as an illustrative, non-limiting example: Val-Cit), is linked to the second spacer unit (-A-), more preferably via the carbonyl group of the second spacer unit, and the C-terminus of the peptide is linked to the first spacer unit (-B-), if present, or to the camptothecin moiety (-C) if the first spacer unit (-B-) is absent.

[0213] In yet another embodiment, the amino acid unit is N-methylvaline-citrulline. In yet another embodiment, the amino acid unit is selected from the group consisting of 5-aminovaleric acid, homophenylalanine-lysine, tetraisoquinolinecarboxylate-lysine, cyclohexylalanine-lysine, isonepecotic acid-lysine, β-alanine-lysine, and isonepecotic acid.

[0214] Preferably, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC).

[0215] In some embodiments, the amino acid unit is selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). Preferably, the amino acid unit is selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). More preferably, the amino acid unit is valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers comprising amino acid units according to these embodiments may be illustrative examples for linkers that are cleavable, particularly by proteases such as cathepsins (e.g., cathepsin B). These and further suitable amino acid units are disclosed, for example, in Salomon et al., "Optimizing Lysosomal Activation of Antibody-Drug Conjugates (ADCs) by Incorporation of Novel Cleavable Dipeptide Linkers," Mol. Pharmaceutics 2019, 16, 12, 4817-4825.

[0216] The first spacer unit (B), if present, is a spacer unit between the amino acid units (W w ) to the camptothecin moiety. Alternatively, the first spacer unit (B) may link the second spacer unit (A) to the camptothecin moiety (C) if the amino acid unit is absent. The first spacer unit may link the camptothecin moiety to Y if both the amino acid unit and the second spacer unit are absent.

[0217] The integer b can be 0 or 1. In preferred embodiments, the integer b is 1. Alternatively, in other embodiments, the integer b is 0 and the first spacer unit is absent.

[0218] The first spacer unit (-B-) can be of two general types: self-immolative and non-self-immolative. A non-self-immolative first spacer unit is one in which some or all of the first spacer unit is an amino acid unit (-W) of the linker (L). w -), which remains attached to the camptothecin moiety (C). Alternatively, exemplary compounds containing a self-immolative first spacer unit can release the drug moiety-D without the need for a separate hydrolysis step. In exemplary embodiments, the self-immolative first spacer unit is a PAB group linked to -Ww- through the amino nitrogen atom of the PAB group and directly linked to -D through a carbonate, carbamate, or ether group. Without being bound by any particular theory or mechanism, Scheme 2 depicts a possible mechanism for drug release of a PAB group directly connected to -D through a carbamate or carbonate group, as supported by Toki et al. (2002) J. Org. Chem. 67:1866-1872. TIFF2024540692000184.tif102128 wherein Q is -(C1-C8)alkyl, -O-(C1-C8)alkyl, -halogen, -nitro or -cyano; m is an integer ranging from 0 to 4, preferably m is 0, 1 or 2, more preferably m is 0 or 1, even more preferably m is 0; and p is in the range of 1 to 20.

[0219] Without being bound by any particular theory or mechanism, Scheme 3 depicts a possible mechanism of drug release for a PAB group directly connected to drug moiety-D via an ether or amine bond. TIFF2024540692000185.tif111128 wherein Q is -(C1-C8)alkyl, -O-(C1-C8)alkyl, -halogen, -nitro or -cyano; m is an integer ranging from 0 to 4, preferably m is 0, 1 or 2, more preferably m is 0 or 1, even more preferably m is 0; and p is in the range of 1 to 20.

[0220] Other examples of self-immolative spacers include, but are not limited to, aromatic compounds electronically similar to the PAB group, such as 2-aminoimidazole-5-methanol derivatives (Hay et al. (1999) Bioorg. Med. Chem. Lett. 9:2237) and ortho- or para-aminobenzyl acetals. Spacers that undergo cyclization upon amide bond hydrolysis can be used, such as substituted and unsubstituted 4-aminobutyric acid amides (Rodrigues et al., Chemistry Biology, 1995, 2, 223), appropriately substituted bicyclo[2.2.1] and bicyclo[2.2.2] ring systems (Storm, et al., J. Amer. Chem. Soc., 1972, 94, 5815), and 2-aminophenylpropionic acid amides (Amsberry, et al., J. Org. Chem., 1990, 55, 5867). Elimination of amine-containing drugs substituted at the alpha position of glycine (Kingsbury, et al., J. Med. Chem., 1984, 27, 1447) is also an example of a self-immolative spacer useful in the exemplary compounds.

[0221] In one embodiment, the first spacer unit is a branched bis(hydroxymethyl)styrene (BHMS) unit as depicted in Scheme 4, which can be used to incorporate and release multiple drugs (D). TIFF2024540692000186.tif44128 wherein Q is -(C1-C8)alkyl, -O-(C1-C8)alkyl, -halogen, -nitro or -cyano; m is an integer ranging from 0 to 4; preferably m is 0, 1 or 2; more preferably m is 0 or 1; even more preferably m is 0; and p is in the range of 1 to 10; n is 0 or 1; and p is in the range of 1 to 20.

[0222] In a preferred embodiment, the first spacer unit has the formula (X): TIFF2024540692000187.tif27128, wherein Q is -(C1-C8)alkyl, -O-(C1-C8)alkyl, -halogen, -nitro, or -cyano; and m is an integer ranging from 0 to 4; preferably, m is 0, 1, or 2; more preferably, m is 0 or 1; and in a highly preferred embodiment, m is 0. Preferably, in formula (X), if an amino acid unit is present, the NH group is attached to the C-terminus of the amino acid unit. Preferably, in formula (X), the C(O) group is attached to the camptothecin moiety (C).

[0223] In a highly preferred embodiment, the first spacer unit has the following structure: Preferably, when an amino acid unit is present, the NH group is a PAB group having an amino acid unit (-W w -), more preferably to the C-terminus of the amino acid unit. Preferably, the C(O) group is attached to the camptothecin moiety (C).

[0224] In some embodiments, the first spacer group (-B-) is a heterocyclic "self-immolative moiety" of Formula I, II, or III attached to the camptothecin moiety and incorporates an amide group which, upon hydrolysis by an intracellular protease, initiates a reaction that ultimately cleaves the first spacer unit (-B-) from the camptothecin moiety such that the drug is released from the conjugate in an active form. The linker moiety is an amino acid unit (-W) adjacent to the first spacer group (-B-) that is a substrate for an intracellular enzyme, e.g., an intracellular protease such as a cathepsin (e.g., cathepsin B), which cleaves the peptide at the amide bond shared with the first spacer group (-B-). w Heterocyclic self-immolative moieties are described, for example, in WO 2019 / 236954.

[0225] In some embodiments, the first spacer unit (-B-) is a heterocyclic self-immolative group selected from Formulas I, II, and III: TIFF2024540692000189.tif78128In the formula, the wavy line indicates the amino acid unit -W w - and indicates the site of covalent attachment to the camptothecin moiety, where U is O, S, or NR 6 and Q is CR 4 or N;V 1 , V 2 and V 3 is an independent CR 4 or N, with the proviso that for Formulas II and III, Q, V 1 and V 2 at least one of is N; T is O pending from the camptothecin moiety (-C); R 1 , R 2 , R 3 and R 4 are H, F, Cl, Br, I, OH, -N(R 5 )2, -N(R 5 )3 + , -(C1-C8) alkyl halide, carboxylate, sulfate, sulfamate, sulfonate, -SO2R 5 , -S(=O)R 5 , -SR5 , -SO2N(R 5 )2, -C(=O)R 5 , -CO2R 5 , -C(=O)N(R 5 )2, -CN, -N3, -NO2, -(C1-C8)alkoxy, -(C1-C8)halosubstituted alkyl, polyethyleneoxy, phosphonate, phosphate, -(C1-C8)alkyl, -(C1-C8)substituted alkyl, -(C2-C8)alkenyl, -(C2-C8)substituted alkenyl, -(C2-C8)alkynyl, -(C2-C8)substituted alkynyl, -(C6-C 20 ) aryl, -(C6-C 20 ) substituted aryl, -(C3-C 20 ) heterocycles, and -(C3-C 20 ) substituted heterocycles; or when taken together, R 2 and R 3 forms a carbonyl (=O) or a spirocarbocyclic ring of 3 to 7 carbon atoms; and R 5 and R 6 is H, -(C1-C8) alkyl, -(C1-C8) substituted alkyl, -(C2-C8) alkenyl, -(C2-C8) substituted alkenyl, -(C2-C8) alkynyl, -(C2-C8) substituted alkynyl, -(C6-C 20 ) aryl, -(C6-C 20 ) substituted aryl, -(C3-C 20 ) heterocycles, and -(C3-C 20 ) substituted heterocycle; wherein: 20 ) substituted aryl, and -(C3-C 20 ) substituted heterocycles include F, Cl, Br, I, OH, -N(R 5 )2, -N(R 5 )3 +, -(C1-C8) alkyl halide, carboxylate, sulfate, sulfamate, sulfonate, -(C1-C8) alkyl sulfonate, -(C1-C8) alkylamino, 4-dialkylaminopyridinium, -(C1-C8) alkyl hydroxyl, -(C1-C8) alkyl thiol, -SO2R 5 , -S(=O)R 5 , -SR 5 , -SO2N(R 5 )2, -C(=O)R 5 , -CO2R 5 , -C(=O)N(R 5 )2, -CN, -N3, -NO2, -(C1-C8)alkoxy, -(C1-C8)trifluoroalkyl, -(C1-C8)alkyl, -(C3-C 12 ) carbocycle, -(C6-C 20 ) aryl, -(C3-C 20 ) is independently substituted with one or more substituents selected from the group consisting of heterocycle, polyethyleneoxy, phosphonate, and phosphate.

[0226] Conjugates containing heterocyclic self-immolative moieties are stable extracellularly or in the absence of enzymes capable of cleaving the amide bond of the self-immolative moiety, but upon entry into a cell or exposure to a suitable enzyme, the amide bond is cleaved, initiating a spontaneous self-immolation reaction that cleaves the bond covalently linking the self-immolative moiety to the camptothecin moiety, thereby releasing the drug in its underivatized or pharmacologically active form.

[0227] The self-immolative moiety in the conjugate may incorporate one or more heteroatoms, thereby providing improved solubility, improving cleavage rate, and / or reducing the aggregation tendency of the conjugate. Thus, heterocyclic self-immolative linker constructs may, in some cases, result in increased efficacy, reduced toxicity, and / or desirable pharmacokinetic and / or pharmacodynamic properties.

[0228] T in Formulas I-III is understood to be O because it is derived from the tertiary hydroxyl (-OH) on the lactone ring portion of the camptothecin moiety.

[0229] Without being limited by theory or any particular mechanism, the presence of electron-withdrawing groups on the heterocyclic ring of Formula I, II, or III may slow the rate of cleavage.

[0230] In one embodiment, the self-immolative moiety is a group of formula I, where Q is N and U is O or S. Such groups have non-linear structural features that improve the solubility of the conjugate. In this context, R is sometimes H, methyl, nitro, or CF. In one embodiment, Q is N and U is O, thereby forming an oxazole ring, and R is H. In another embodiment, Q is N and U is S, thereby forming a thiazole ring, optionally substituted at R with a Me or CF group.

[0231] In another exemplary embodiment, the self-immolative moiety is 1 and V 2 is a group of formula II, wherein Q, V are independently N or CH. 1 and V 2 are each N. In another embodiment, Q and V 1 is N, while V 2 In another embodiment, Q and V are 2 is N, while V 1 In another embodiment, Q and V are 1 are both CH and V 2 is N. In another embodiment, Q is N, while V 1 and V 2 are both CH.

[0232] In another embodiment, the self-immolative moiety is Q, V 1 , V 2 and V 3is a group of formula III, wherein each Q is independently N or CH. In another embodiment, Q is N, while V 1 , V 2 and V 3 are each N. In another embodiment, Q, V 1 , and V 2 are CH, while V 3 is N. In another embodiment, Q, V 2 and V 3 are CH, while V 1 is N. In another embodiment, Q, V 1 and V 3 are CH, while V 2 is N. In another embodiment, Q and V 2 are both N, while V 1 and V 3 In another embodiment, Q and V are both CH. 2 are both CH, while V 1 and V 3 are both N. In another embodiment, Q and V 3 are both N, while V 1 and V 2 are both CH.

[0233] Preferably, the linker (L) has the formula: a -W w -B b - ## wherein integer a is 1, integer b is 1, and integer w is 2, 3 or 4, more preferably integer w is 2 or 3; in a highly preferred embodiment, integer w is 2; and -A-, each -W- and -B- are as defined herein; * indicates a point of attachment to Y; and ## indicates a point of attachment to the camptothecin moiety (C).

[0234] Preferably, the linker (L) has the following structure: *-A a -W w -B b - ## wherein -A- is a second spacer unit as described herein; a is an integer as described herein; preferably a is 1; -B- is a first spacer unit as described herein; b is an integer as described herein; preferably b is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C); -W w - is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w- can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0235] Preferably, the linker L has the following structure: TIFF2024540692000190.tif31128 where -A- is a second spacer unit as described herein; a is an integer as described herein; preferably a is 1; -W w - is an amino acid unit as described herein; w is an integer as described herein; preferably, w is 2, 3, or 4 (i.e., preferably, -W w - is a dipeptide, tripeptide, or tetrapeptide), for example, w can be 1 or 2, and more preferably w is 2 or 3 (i.e., more preferably, -W w - is a dipeptide or tripeptide), and in highly preferred embodiments, w is 2 (i.e., even more preferably, -W w - is a dipeptide); Q is as defined herein; m is an integer as defined herein, preferably m is 0; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w - is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0236] More preferably, the linker L has the following structure: TIFF2024540692000191.tif36128 where, TIFF2024540692000192.tif28128 is as defined herein; * indicates attachment point to Y; and # indicates amino acid unit -W w - (if present) indicating the point of attachment to the or NH group; -W w - is an amino acid unit as described herein; w is an integer as described herein, preferably w is 2, 3, or 4 (i.e., preferably -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably w is 2 or 3 (i.e., more preferably -W w - is a dipeptide or tripeptide), and in highly preferred embodiments, w is 2 (i.e., even more preferably, -W w - is a dipeptide); Q is as defined herein; m is an integer as defined herein, preferably m is 0; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w- is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0237] Even more preferably, the linker L has the following structure: TIFF2024540692000193.tif35128 where, -Ww - is an amino acid unit as described herein; w is an integer as described herein, preferably w is 2, 3, or 4 (i.e., preferably -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably w is 2 or 3 (i.e., more preferably -W w - is a dipeptide or tripeptide), and in highly preferred embodiments, w is 2 (i.e., even more preferably, -W w - is a dipeptide); * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w - is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w- can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0238] In a preferred embodiment, the linker L has the following structure: TIFF2024540692000194.tif52129This is the amino acid unit -W w containing the dipeptide valine-citrulline as a where * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Such linkers are illustrative examples, particularly for linkers that are cleavable by proteases, such as, for example, cathepsins (e.g., cathepsin B).

[0239] In another preferred embodiment, the linker L has the following structure: TIFF2024540692000195.tif38129This is the amino acid unit -W w containing the dipeptide valine-alanine as a where * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Such linkers are illustrative examples, particularly for linkers that are cleavable by proteases, such as, for example, cathepsins (e.g., cathepsin B).

[0240] Preferably, the linker (L) has the formula: TIFF2024540692000196.tif29128, wherein integer b is 1 and integer w is 2, 3 or 4, more preferably integer w is 2 or 3, and in a highly preferred embodiment integer w is 2; and TIFF2024540692000197.tif26128 is as described herein; R S are each independently a second polyalkylene glycol unit as described herein; preferably, each R S is independently a second polyethylene glycol unit as described herein; each M is independently as described herein, preferably each M is -O-; s* is an integer as described herein; preferably s* is 1; each -W-, and -B- is as defined herein; * indicates the point of attachment to Y; and ## indicates the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w- is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). More preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0241] Preferably, the linker L has the following structure: TIFF2024540692000198.tif44128 where, TIFF2024540692000199.tif26128 is as described herein; R S are each independently a second polyalkylene glycol unit as described herein; preferably, each R S is independently a second polyethylene glycol unit as described herein; each M is independently as described herein, preferably each M is -O-; s* is an integer as described herein; preferably s* is 1; -W w - is an amino acid unit as described herein; w is an integer as described herein; preferably, w is 2, 3, or 4 (i.e., preferably, -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably w is 2 or 3 (i.e., more preferably -W w - is a dipeptide or tripeptide), and in highly preferred embodiments, w is 2 (i.e., even more preferably, -W w - is a dipeptide); Q is as described herein; m is an integer as described herein, preferably m is 0; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w- is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0242] More preferably, the linker L has the following structure: TIFF2024540692000200.tif35128 where, TIFF2024540692000201.tif38128 is as defined herein; R S are each independently a second polyalkylene glycol unit as defined herein; preferably each R S is independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; s* is an integer as defined herein; preferably s* is 1; * indicates the point of attachment to Y; and # indicates the amino acid unit -W w - (if present) indicating the point of attachment to the or NH group; -W w - is an amino acid unit as described herein; w is an integer as described herein, preferably w is 2, 3, or 4 (i.e., preferably -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably w is 2 or 3 (i.e., more preferably -W w - is a dipeptide or tripeptide), and in highly preferred embodiments, w is 2 (i.e., even more preferably, -W w - is a dipeptide); Q is as defined herein; m is an integer as defined herein, preferably m is 0; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w- is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0243] Even more preferably, the linker L has the following structure: TIFF2024540692000202.tif36128 where, RS are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein, preferably each M is -O-; s* is an integer as defined herein; preferably s* is 1; -W w - is an amino acid unit as described herein; w is an integer as described herein, preferably w is 2, 3, or 4 (i.e., preferably -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably w is 2 or 3 (i.e., more preferably -W w - is a dipeptide or tripeptide), and even more preferably, w is 2 (i.e., even more preferably, -W w - is a dipeptide); * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w - is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w- can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). Linkers according to these embodiments can be illustrative examples for linkers that are cleavable, inter alia, by proteases such as cathepsins (e.g., cathepsin B).

[0244] In a preferred embodiment, the linker L has the following structure: TIFF2024540692000203.tif49128This is the amino acid unit -W w - containing the dipeptide valine-citrulline; where R S is a second polyalkylene glycol unit as defined herein; preferably, R S is a second polyethylene glycol unit as defined herein; M is as defined herein; preferably M is -O-; and * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Linkers according to these embodiments may be illustrative examples, particularly for linkers that are cleavable by proteases such as, for example, cathepsins (e.g., cathepsin B).

[0245] In another preferred embodiment, the linker L has the following structure: TIFF2024540692000204.tif36128This is the amino acid unit -W wcontaining the dipeptide valine-alanine as a where R S is a second polyalkylene glycol unit as defined herein; preferably, R S is a second polyethylene glycol unit as defined herein; M is as defined herein; preferably M is -O-; and * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Linkers according to these embodiments may be illustrative examples, particularly for linkers that are cleavable by proteases such as, for example, cathepsins (e.g., cathepsin B).

[0246] In some embodiments, the linker L has the formula: a -W w - ## wherein -A- is a second spacer unit as defined herein; the integer a associated with the second spacer unit is as defined herein; -W w - is an amino acid unit as defined herein; the integer w associated with the amino acid unit W is as defined herein; the first spacer unit (-B b * denotes a point of attachment to Y; and # denotes a point of attachment to the camptothecin moiety (-C). Preferably, the integer a is 1. Preferably, the integer w is 2, 3, or 4, more preferably, the integer w is 2 or 3, and even more preferably, the integer w is 2. Preferably, in these embodiments, the amino acid unit -W w- is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w - can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ). In any one of these embodiments, the second spacer unit -A- has the structure: TIFF2024540692000205.tif26128, wherein TIFF2024540692000206.tif26128 is as defined herein.

[0247] The linker L may have the following structure: TIFF2024540692000207.tif27128 where, TIFF2024540692000208.tif26128 is as defined herein; * indicates attachment point to Y; and # indicates amino acid unit -W w - Shows connection points; -W w - is an amino acid unit as described herein; w is an integer as described herein, preferably w is 2, 3, or 4 (i.e., preferably -W w - is a dipeptide, tripeptide or tetrapeptide), and more preferably, the integer w is 2 or 3 (i.e., more preferably, -W w - is a dipeptide or tripeptide), and even more preferably, w is 2 (i.e., even more preferably, -W w - is a dipeptide); * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Preferably, in these embodiments, the amino acid unit -W w - is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), alanine-alanine (i.e., Ala-Ala or AA), and phenylalanine-lysine (i.e., Phe-Lys or FK). More preferably, in these embodiments, the amino acid unit is a dipeptide selected from the group consisting of valine-citrulline (i.e., Val-Cit or VC), valine-alanine (i.e., Val-Ala or VA), and phenylalanine-lysine (i.e., Phe-Lys or FK). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC) or valine-alanine (i.e., Val-Ala or VA). Even more preferably, in these embodiments, the amino acid unit is valine-citrulline (i.e., Val-Cit or VC). Alternatively, in these embodiments, the amino acid unit -W w- can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), phenylalanine-glutamine (i.e., Phe-Gln or FQ), and threonine-threonine (i.e., Thr-Thr or TT). In these embodiments, the amino acid unit can be a dipeptide selected from the group consisting of valine-glutamine (i.e., Val-Gln or VQ), leucine-glutamine (i.e., Leu-Gln or LQ), and phenylalanine-glutamine (i.e., Phe-Gln or FQ). In these embodiments, the amino acid unit can be valine-glutamine (i.e., Val-Gln or VQ) or leucine-glutamine (i.e., Leu-Gln or LQ).

[0248] In some embodiments, the linker L may have the following structure: TIFF2024540692000209.tif39128This is the amino acid unit -W w containing the dipeptide valine-citrulline as a where * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0249] In some embodiments, the linker L may have the following structure: TIFF2024540692000210.tif28128This is the amino acid unit -W w containing the dipeptide valine-alanine as a where * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0250] In some embodiments, the linker (-L-) has the formula: a - ## wherein -A- is a second spacer unit as defined herein; the integer a associated with the second spacer unit is 1; and the amino acid unit -W w- is absent; the first spacer unit (-B-) is absent; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In any one of these embodiments, the second spacer unit -A- has the structure: TIFF2024540692000211.tif26128, wherein TIFF2024540692000212.tif26128 is as defined herein.

[0251] The linker (-L-) may have the following structure: TIFF2024540692000213.tif22128 where, TIFF2024540692000214.tif22128 is as defined herein; * indicates the point of attachment to the Y; and # indicates the point of attachment to the camptothecin moiety (-C).

[0252] In some embodiments, the linker L may have the following structure: TIFF2024540692000215.tif25128 where * denotes the point of attachment to the Y; and # denotes the point of attachment to the camptothecin moiety (-C).

[0253] Linker*-A a -Q CO q -G- ## In some embodiments, the linker L has the following structure: a -Q CO q -G- ## where -A- is a second spacer unit, as described herein; a is 0 or 1, as described herein; and each -Q CO- is independently a connector unit; q is 0 or 1; and -G- is a first spacer unit comprising a sugar moiety; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). Linkers comprising a sugar moiety, e.g., a glucuronic acid moiety, are described, for example, in Jeffrey et al., "Development and Properties of beta-Glucuronide Linkers for Monoclonal Antibody-Drug Conjugates", Bioconjugate Chem. 2006, 17, 831-840, doi: 10.1021 / bc0600214; WO 2019 / 236954; and WO 2015 / 057699.

[0254] Linker*-A a -Q CO q -G- ## In the structure *-A, the second spacer unit -A-, when present, can be any second spacer unit as described herein. a -Q CO q -G- ## In a linker having the formula: CO (if present) or the first spacer unit containing the sugar moiety. The second spacer unit (-A-), if present, connects Y to the connector unit (Q CO ) or any chemical group or moiety that can be linked to a connector unit Q. CO If -Q is not present, Y may be linked to a first spacer unit (-G-) comprising a sugar moiety. In this regard, Y is attached to a second spacer unit (-A-) as described herein. The second spacer unit (-A-) may be linked to a connector unit (-Q CO Depending on whether a connector unit (-Q COPreferably, the connector unit (-Q) comprises or is a functional group capable of forming a bond to a first spacer unit (-G-) or to a first spacer unit (-Q-) bearing a sugar moiety. CO Functional groups capable of forming a bond to the first spacer unit (-G-) or to the first spacer unit (-G-) comprising a sugar moiety include, for example: TIFF2024540692000216.tif14128 or a carbonyl group depicted as -C(O)-. The integer a associated with the second spacer unit can be 0 or 1. Preferably, the integer a is 1. Alternatively, in other embodiments, the second spacer unit is absent (a = 0).

[0255] Linker*-A a -Q CO q -G- ## In the formula (I), the second spacer unit -A-, when present, can be any second spacer unit as described herein. In some embodiments, the second spacer unit -A-, when present, has the structure: TIFF2024540692000217.tif26128, wherein TIFF2024540692000218.tif26128 is as defined herein. Thus, in some embodiments, the linker (L) has the structure: TIFF2024540692000219.tif29128, where L P , R S ,s*,M,Q CO , q, and G are as defined herein; * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0256] Connector unit (-Q CO-) may be included when it is desirable to add additional distance between -Y-, or, if present, the second spacer unit (-A-), and the first spacer unit (-G-) that includes the sugar moiety. In some embodiments, the extra distance may aid in activation within the first spacer unit (-G-) that includes the sugar moiety. Thus, the connector unit (-Q CO -), if present, extends the framework of the linker (-L-). In this regard, the connector unit (-Q CO -) is covalently linked at one end to -Y- or, if a second spacer unit -A- is present, to a second spacer unit (-A-), and is linked at the other end to a connector unit (-Q CO The connector unit Q is covalently attached at its other end to a first spacer unit (-G-) that contains a sugar moiety. CO The integer q associated with can be 0 or 1. Preferably, the integer q is 1. Alternatively, in other embodiments, the connector unit Q CO does not exist (q = 0).

[0257] Connector unit (-Q CO The connector unit Q, when present, serves to link the first spacer unit (-G-), which includes the sugar moiety, to the second spacer unit (-A-), if present, or to -Y-. CO can be any chemical group or moiety that serves to provide a connection of the first spacer unit (-G-), including the sugar moiety, to the second spacer unit (-A-), if present, or to -Y-. The connector unit can be composed of, for example, one or more (e.g., 1 to 10, preferably 1, 2, 3, or 4) natural or unnatural amino acids, amino alcohols, amino aldehydes, and diamino residues. In some embodiments, the connector unit (-Q CO -) is a single natural or unnatural amino acid, amino alcohol, amino aldehyde, or diamino residue. In some embodiments, the amino acid that can serve as a connector unit is β-alanine. In particular, the connector unit can be a single β-alanine.

[0258] In some embodiments, the connector unit (-Q CO -) has the formula shown below: TIFF2024540692000220.tif98135 where the wavy line indicates the connection of the connector unit within the linker (-L-) or, if the second spacer unit (-A-) is absent, to -Y-; and where R 111 is hydrogen, hydroxybenzyl, methyl, isopropyl, isobutyl, sec-butyl, -CH2OH, -CH(OH)CH3, -CH2CH2SCH3, -CH2CONH2, -CH2COOH, -CH2CH2CONH2, -CH2CH2COOH, -(CH2)3NHC(=NH)NH2, -(CH2)3NH2, -(CH2)3NHCOCH3, -(CH2)3NHCHO, -(CH2)4NHC(=NH)NH2, -(CH2)4NH2, -(CH2)4NHCOCH3, -(CH2)4NHCHO, -(CH2)3NHCONH2, -(CH2)4NHCONH2, -CH2CH2CH(OH)CH2NH2, 2-pyridylmethyl-, 3-pyridylmethyl-, 4-pyridylmethyl-, TIFF2024540692000221.tif25144, and each R 100 are independently selected from hydrogen or —(C 1 -C 3 )alkyl, preferably hydrogen or CH 3 ; and the subscript c is an independently selected integer from 1 to 10, preferably 1 to 3.

[0259] In a preferred embodiment, the connector unit has the following structure: CO -), which has a carbonyl group for connection to the first spacer unit (-G-) that includes a sugar moiety, and an NH group for connection to the second spacer unit (-A-), if present, as follows: TIFF2024540692000222.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6)alkylene and c is 1.

[0260] More preferably, the connector unit (-Q CO -) has the following structure: TIFF2024540692000223.tif17128 wherein the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-) (if present), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4.

[0261] Even more preferably, the connector unit (-Q CO -) has the following structure: TIFF2024540692000224.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-) (if present), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0262] Another representative connector unit (-Q) having a carbonyl group for connection to a first spacer unit (-G-) containing a sugar moiety. CO -) is as follows: TIFF2024540692000225.tif12128 where R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, or -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-. In some embodiments, R 13 is -(C1-C6)alkylene.

[0263] Another representative connector unit having an NH moiety connecting to a first spacer unit (-G-) comprising a sugar moiety is: TIFF2024540692000226.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is 1 to 14. In some embodiments, R 13 is -(C1-C6)alkylene and the subscript c is 1.

[0264] Another representative connector unit (-Q) having an NH moiety connected to a first spacer unit (-G-) containing a sugar moiety. CO -) is as follows: TIFF2024540692000227.tif7128 where R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, -C(=O)(C1-C 10 ) alkylene- or -(C1-C6) alkylene-C(=O)-(C1-C6) alkylene.

[0265] A first spacer unit (-G-) having a sugar moiety must be present, structure *-A a -Q CO q -G- ## In some embodiments, the first spacer unit (-G-) comprising a sugar moiety forms a cleavable bond with the camptothecin moiety (-C). In some embodiments, the first spacer unit (-G-) comprising a sugar moiety is the only component of the linker having a connector unit (-Q CO -) (if present). In some embodiments, the cleavable bond is within the first spacer unit (-G-) that includes a sugar moiety, but allows for release of the free drug (e.g., by a 1,6-elimination reaction after cleavage). Functional groups for forming cleavable bonds can include, for example, sugars for forming glycosidic bonds.

[0266] The structure and sequence of the first spacer unit (-G-) comprising a sugar moiety can be such that the unit is cleaved by the action of an enzyme present at the target site. In other embodiments, the first spacer unit (-G-) comprising a sugar moiety can be cleavable by other mechanisms. The first spacer unit (-G-) comprising a sugar moiety can include one or more cleavage sites.

[0267] Preferably, the first spacer unit (-G-) comprising a sugar moiety comprises a sugar cleavage site. In some such embodiments, the first spacer unit (-G-) comprising a sugar moiety comprises a sugar moiety (Su) linked to a self-immolative group via an oxygen glycosidic bond. In such aspects, the self-immolative group is considered to be part of the first spacer unit (-G-) comprising a sugar moiety. In this regard, a "self-immolative group" refers to a group consisting of three spaced chemical moieties: a sugar moiety (via a glycosidic bond), a camptothecin moiety (-C), and a -Q CO -unit and / or -A-unit are present, depending on whether connector unit -Q CO The glycosidic bond may be a trifunctional chemical moiety capable of covalently linking the first spacer unit (-A-, the second spacer unit -A-, or -Y-) together. The glycosidic bond may be cleavable at the target site to initiate a self-sacrificial reaction sequence leading to drug release. The specific sugar moiety may be selected from the group consisting of, for example, glucuronic acid, galactose, glucose, arabinose, mannose-6-phosphate, fucose, rhamnose, gulose, allose, 6-deoxyglucose, lactose, maltose, cellobiose, gentiobiose, maltotriose, GlcNAc, GalNAc, and maltohexaose.

[0268] Thus, the first spacer unit (-G-) comprising the sugar moiety has the formula: TIFF2024540692000228.tif21128, wherein the sugar moiety (Su) is linked to a self-immolative group (K) via a glycosidic bond (-O'-), wherein the self-immolative group K covalently bonds to the camptothecin moiety, and -Q COForms a covalent bond with -, -A-, or -Y- (as the case may be).

[0269] The first spacer unit (-G-) comprising a sugar moiety can be, for example, a spacer unit having the formula: TIFF2024540692000229.tif47128, where Su is a sugar moiety, -O'- represents an oxygen glycosidic bond; each R is independently hydrogen, halogen, -CN, or -NO2; and the wavy line represents -Q CO indicates connection to -, -A-, or -Y- (as the case may be), and the asterisk indicates connection to the camptothecin moiety (directly or indirectly via a spacer unit; if present, the spacer unit may be, for example, -(C=O)-).

[0270] In some such embodiments, the sugar cleavage site is recognized by β-glucuronidase and the first spacer unit (-G-) comprising the sugar moiety comprises a glucuronide unit. The glucuronide unit has the formula: TIFF2024540692000230.tif20128, wherein the glucuronic acid is linked to a self-immolative group (K) via a glycosidic bond (—O′—); wherein the self-immolative group K is covalently bonded to the camptothecin moiety (either directly or indirectly through a spacer unit; the spacer unit, if present, can be, for example, —(C═O)—), and —Q CO Forms a covalent bond with -, -A-, or -Y- (as the case may be).

[0271] The glucuronide unit may, for example, be represented by the formula: TIFF2024540692000231.tif36128, In the formula, the wavy line represents -Q CO -, -A-, or -Y- (as the case may be), and an asterisk indicates a covalent attachment to the camptothecin moiety -C (directly or indirectly via a spacer unit; if present, the spacer unit may be, for example, -(C=O)-).

[0272] In some embodiments, the first spacer unit (-G-) comprising a sugar moiety comprises a sugar cleavage site, -SC, i.e., the combination of the first spacer unit (-G-) comprising a sugar moiety and the camptothecin moiety (in the formula below, the camptothecin moiety is exceptionally designated "D") is represented by the formula: TIFF2024540692000232.tif100128 wherein Su is a sugar moiety, D is a camptothecin moiety, -O'- represents an oxygen glycosidic bond; each R is independently hydrogen or halogen, -CN, -NO2 or other electron-withdrawing group, -Q CO - is a connector unit as described herein; where the wavy bond indicates a covalent connection to -A- or -Y- (as the case may be).

[0273] When the first spacer unit (-G-) containing a sugar moiety contains a glucuronide unit, -SC, i.e., the combination of the first spacer unit (-G-) containing a sugar moiety and the camptothecin moiety (in the formula below, the camptothecin moiety is exceptionally represented as "D"), can be represented, for example, by the following formula: TIFF2024540692000233.tif77128 where the wavy bond indicates a covalent connection to -A- or -Y- (as the case may be); D is a camptothecin moiety; and -Q CO - is a connector unit as described herein.

[0274] Without being bound by theory, Scheme 1a depicts the mechanism of free drug release of a camptothecin drug unit connected via the nitrogen atom of an amine substituent from the free drug to a releasable linker comprising a glucuronide unit. TIFF2024540692000234.tif74139

[0275] In a preferred embodiment, the linker (L) has the following structure: TIFF2024540692000235.tif59128 where, -A- is a second spacer unit as described herein; a is an integer as described herein, preferably a is 1; -Q CO - is a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), if present, may have a carbonyl group for connection to the first spacer unit (-G-), which comprises a sugar moiety, and an NH group for connection to the second spacer unit (-A-), if present, and may be as follows: TIFF2024540692000236.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6) alkylene and c is 1; preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000237.tif16128 wherein the wavy line adjacent to the nitrogen indicates a covalent attachment to the second spacer unit (-A-), if present, and the wavy line adjacent to the carbonyl indicates a covalent attachment to the first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4; more preferably, in these embodiments, a connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000238.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-) (if present), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0276] More preferably, the linker (L) has the following structure: TIFF2024540692000239.tif58128 where, TIFF2024540692000240.tif22128 is as defined herein; * denotes a connection point to -Y-; and # denotes a connector unit (-Q CO -) (if present) or indicate the point of attachment to the NH group; -Q CO - is a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), when present, may have a carbonyl group for connection to the first spacer unit (-G-) comprising a sugar moiety and an NH group for connection to the second spacer unit (-A-), and may be as follows: TIFF2024540692000241.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10)heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6) alkylene and c is 1. Preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000242.tif16128 wherein the wavy line adjacent to the nitrogen indicates a covalent connection to a second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates a covalent connection to a first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4. More preferably, in these embodiments, the connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000243.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-) (if present), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0277] Even more preferably, the linker (L) has the following structure: TIFF2024540692000244.tif59128 where, Q COis a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), when present, may have a carbonyl group for connection to the first spacer unit (-G-) comprising a sugar moiety and an NH group for connection to the second spacer unit (-A-), and may be as follows: TIFF2024540692000245.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6) alkylene and c is 1. Preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000246.tif16128 wherein the wavy line adjacent to the nitrogen indicates a covalent connection to a second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates a covalent connection to a first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4; more preferably, in these embodiments, a connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000247.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0278] Even more preferably, the linker L may have the following structure: TIFF2024540692000248.tif51128 where * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0279] In a preferred embodiment, the linker L has the following structure: TIFF2024540692000249.tif60128 where, TIFF2024540692000250.tif26128 is as described herein; R S are each independently a second polyalkylene glycol unit as described herein; preferably, each R S are independently a second polyethylene glycol unit as described herein; each M is independently as described herein; preferably each M is -O-; s* is an integer as described herein; preferably s* is 1; -Q CO - is a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), when present, may have a carbonyl group for connection to the first spacer unit (-G-) comprising a sugar moiety and an NH group for connection to the second spacer unit (-A-), and may be as follows: TIFF2024540692000251.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6) alkylene and c is 1. Preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000252.tif17128 wherein the wavy line adjacent to the nitrogen indicates a covalent connection to a second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates a covalent connection to a first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4. More preferably, in these embodiments, the connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000253.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0280] More preferably, the linker (L) has the following structure: TIFF2024540692000254.tif57128 where, TIFF2024540692000255.tif30128 is as defined herein; R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S is independently a second polyethylene glycol unit as defined herein; each M is independently as defined herein; preferably each M is -O-; s* is an integer as defined herein; preferably s* is 1; * denotes a point of attachment to Y; * denotes a point of attachment to -Y-; and # denotes a connector unit (-Q CO -) (if present) or indicate the point of attachment to the NH group; -Q CO - is a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), when present, may have a carbonyl group for connection to the first spacer unit (-G-) comprising a sugar moiety and an NH group for connection to the second spacer unit (-A-), and may be as follows: TIFF2024540692000256.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10)heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13 is -(C1-C6) alkylene and c is 1. Preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000257.tif17128 wherein the wavy line adjacent to the nitrogen indicates a covalent connection to a second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates a covalent connection to a first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4. More preferably, in these embodiments, the connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000258.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0281] More preferably, the linker (L) has the following structure: TIFF2024540692000259.tif60128 where, R Sare each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as described herein; each M is independently as defined herein; preferably each M is -O-; s* is an integer as defined herein; preferably s* is 1. Q CO is a connector unit as defined herein; q is an integer as defined herein, preferably q is 1; * denotes the point of attachment to Y; and ## denotes the point of attachment to the camptothecin moiety (-C). In these embodiments, the connector unit (Q CO ), when present, may have a carbonyl group for connection to the first spacer unit (-G-) comprising a sugar moiety and an NH group for connection to the second spacer unit (-A-), and may be as follows: TIFF2024540692000260.tif23128 where, in each case, R 13 is -(C1-C6) alkylene-, -(C3-C8) carbocyclo-, -arylene-, -(C1-C 10 )heteroalkylene-, -(C3-C8)heterocyclo-, -(C1-C 10 ) alkylene-arylene-, -arylene-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)carbocyclo)-, -(C3-C8)carbocyclo-(C1-C 10 ) alkylene-, -(C1-C 10 ) alkylene-(C3-C8)heterocyclo-, and -(C3-C8)heterocyclo-(C1-C 10 ) alkylene-, and the subscript c is an integer ranging from 1 to 4. In some embodiments, R 13 is -(C1-C6) alkylene, and c is an integer ranging from 1 to 4. In a preferred embodiment, R 13is -(C1-C6) alkylene and c is 1. Preferably, in these embodiments, the connector unit (-Q CO -), when present, can have the following structure: TIFF2024540692000261.tif16128 where the wavy line adjacent to the nitrogen indicates a covalent connection to a second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates a covalent connection to a first spacer group (-G-) comprising a sugar moiety; and m is an integer ranging from 1 to 6, preferably 2 to 6, more preferably 2 to 4. More preferably, in these embodiments, the connector unit (-Q CO -), when present, has the following structure: TIFF2024540692000262.tif13128 where the wavy line adjacent to the nitrogen indicates the covalent connection to the second spacer unit (-A-), and the wavy line adjacent to the carbonyl indicates the covalent connection to the first spacer group (-G-) that comprises a sugar moiety.

[0282] Even more preferably, the linker L has the following structure: TIFF2024540692000263.tif50128 where, R S are each independently a second polyalkylene glycol unit as defined herein; preferably, each R S are independently a second polyethylene glycol unit as described herein; each M is independently as defined herein; preferably each M is -O-; s* is an integer as defined herein; preferably s* is 1. * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0283] Also preferably, the linker L has the following structure: TIFF2024540692000264.tif58128, where * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0284] In one embodiment, the linker L has the following structure: TIFF2024540692000265.tif58128, where * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C). In this embodiment, Y can be as defined herein; preferably, Y can be NH.

[0285] Linker*-A a -U AT u -Sulf- ## In some embodiments, the linker L has the following structure: a -U AT u -Sulf- ## wherein: -A- is a second spacer unit; a is 0 or 1; and each -U AT u - is independently a connecting unit; u is 0 or 1; and -Sulf- is a first spacer unit comprising a sulfatase-cleavable moiety; * indicates the point of attachment to Y; and ## indicates the point of attachment to the camptothecin moiety (-C). For sulfatase-cleavable linkers, see, e.g., Bargh et al., "Sulfatase-cleavable linkers for antibody-drug conjugates", Chemical Science, 2020, 11, 2375-2380, doi: 10.1039 / c9sc06410a.

[0286] Structure*-A a -U AT u -Sulf- ## In a linker having the formula: AT ) (if present) or to the first spacer unit containing the sulfatase-cleavable moiety. The second spacer unit (-A-) serves to link Y to the connecting unit (U AT)。 Alternatively, the second spacer unit (-A-) can be any chemical group or moiety that can be linked to a connecting unit (U AT If the second spacer unit (-A-) is not present, Y may be linked to a first spacer unit (-Sulf-) that includes a sulfatase-cleavable moiety. In this regard, Y is attached to a second spacer unit (-A-) as described herein. The second spacer unit (-A-) is connected to a connecting unit (-U AT Depending on whether a connection unit (-U AT Preferably, the linking unit (-U) comprises or is a functional group capable of forming a bond to a linking unit (-U) or to a first spacer unit (-Sulf-) bearing a sulfatase-cleavable moiety. AT Functional groups capable of forming a bond to a sulfatase-cleavable moiety (-Sulf-) or to a first spacer unit containing a sulfatase-cleavable moiety (-Sulf-) include, for example: TIFF2024540692000266.tif11128 or a carbonyl group depicted as -C(O)-. The integer a associated with the second spacer unit can be 0 or 1. Preferably, the integer a is 1. Alternatively, in other embodiments, the second spacer unit is absent (a = 0).

[0287] Linker*-A a -U AT u -Sulf- ## In the formula (I), the second spacer unit -A- can be any second spacer unit as described herein. In some embodiments, the second spacer unit -A-, when present, has the structure: TIFF2024540692000267.tif26128, wherein TIFF2024540692000268.tif26128 is as defined herein. Thus, in some embodiments, the linker (L) has the structure: TIFF2024540692000269.tif33128, where L P , R S ,s*,M,U AT, u, and Sulf are as defined herein; * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0288] Connection Unit (-U AT A linking unit (-U) may be included if desired to add additional distance between -Y- or, if present, the second spacer unit (-A-) and the first spacer unit (-Sulf-) containing the sulfatase-cleavable moiety. AT -), if present, extends the framework of the linker (-L-). In this regard, the linking unit (-U AT -) can be covalently linked at one end to -Y- or, if present, to the second spacer unit (-A-), and the connecting unit (-U AT -) is covalently attached at its other end to a first spacer unit (-Sulf-) that contains a sulfatase-cleavable group.

[0289] Connection Unit (-U AT -) may be any chemical group or moiety that serves to provide a connection of the first spacer unit (-Sulf-) comprising the sulfatase-cleavable moiety to the second spacer unit (-A-), if present, or to -Y-.

[0290] In some embodiments, a connection unit (U AT ) has the formula shown below: TIFF2024540692000270.tif22128, wherein v is an integer ranging from 1 to 6; preferably, v is 1 or 2; more preferably, v is 2; and v* is an integer ranging from 1 to 6; preferably, v* is 1 or 2; more preferably, v* is 1; * denotes the point of attachment to the second spacer unit (-A-) (if present), and # denotes the point of attachment to the sulfatase-cleavable moiety (Sulf).

[0291] Preferably, the first spacer unit (Sulf) comprising the sulfatase-cleavable moiety has the formula shown below: TIFF2024540692000271.tif39128 where X is hydrogen (H) or an electron-withdrawing group, such as NO2; * is a connecting unit (U AT ) (if present) or (-A-) (if present) denotes the point of attachment to the camptothecin moiety (-C); and # denotes the point of attachment to the camptothecin moiety (-C).

[0292] In some embodiments, the linker L may have the following structure: TIFF2024540692000272.tif49128where X is H or NO2; * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0293] In some embodiments, the linker L may have the following structure: TIFF2024540692000273.tif53128 where, X is H or NO2; R S is a second polyalkylene glycol unit as defined herein; preferably, R S is a second polyethylene glycol unit as defined herein; M is as defined herein; preferably M is —O—; * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0294] Third spacer unit In some embodiments, when a first spacer unit (-B-), or a first spacer unit comprising a sugar moiety (-G-), or a first spacer unit comprising a sulfatase-cleavable moiety (Sulf) is present, the linker (L) may include an optional third spacer unit (-E-), which is disposed between the first spacer unit (-B-), or the first spacer unit comprising a sugar moiety (-G-), or the first spacer unit comprising a sulfatase-cleavable moiety (Sulf) and the camptothecin moiety (-C). The third spacer unit may be a functional group that can facilitate connection of the first spacer unit (-B-), or the first spacer unit comprising a sugar moiety (-G-), or the first spacer unit comprising a sulfatase-cleavable moiety (Sulf) to the camptothecin moiety (-C), or it may provide an additional structural component that can facilitate release of the camptothecin moiety (-C) from the remainder of the conjugate. Suitable third spacer units are described, for example, in WO 2019 / 236954.

[0295] In some embodiments, the third spacer unit (-E-) is attached to the first spacer unit (-B-) and the camptothecin moiety (-C). Thus, the linker (-L-) has the structure *-A a -W w -B b -E- ## where -E- is a third spacer unit as described herein; and where -A-, a, -W-, w, and -B- may have the structure *-A a -W w -B b - ## is as described herein with respect to the linker (L) having the formula:

[0296] In other embodiments, the third spacer unit (-E-) is linked to the first spacer unit (-G-) comprising a sugar moiety and the camptothecin moiety (-C-). Thus, the linker (-L-) has the structure *-A a -QCO q -GE- ## where -E- is a third spacer unit as described herein; and where -A-, a, -Q CO -, q, and G are specifically related to the structure *-A a -Q CO q -G- ## where in each instance * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0297] In other embodiments, the third spacer unit (-E-) is linked to the first spacer unit (-Sulf-) that includes the sulfatase-cleavable moiety and the camptothecin moiety (-C). Thus, the linker (-L-) has the structure *-A a -U AT u -Sulf-E- ## where -E- is a third spacer unit as described herein; and where -A-, a, -U AT -, u, and Sulf are especially found in the structure *-A a -U AT u -Sulf- ## where in each instance * denotes the point of attachment to -Y-; and ## denotes the point of attachment to the camptothecin moiety (-C).

[0298] In some embodiments, an exemplary third spacer unit, -E-, has the formula: Represented by TIFF2024540692000274.tif55128, In the formula, EWG represents an electron-withdrawing group, and R 1is —H or (C1-C4)alkyl, and the subscript n is 1 or 2. In some embodiments, EWG is selected from the group consisting of —CN, —NO2, —CX3, —X, C(═O)OR′, —C(═O)N(R′), —C(═O)R′, —C(═O)X, —S(═O)2R′, —S(═O)2OR′, —S(═O)2NHR′, —S(═O)2N(R′), —P(═O)(OR′), —P(═O)(CH3)NHR′, —NO, —N(R′) + wherein X is -F, -Br, -Cl, or -I, and R' is independently selected from the group consisting of hydrogen and (C-C)alkyl, and wherein the wavy line adjacent to the nitrogen atom in each of formulas (a), (a'), (a"), (b) and (b') is the point of covalent attachment to the first spacer unit (-B-), and the wavy line adjacent to the carbonyl carbon atom of formulas (b) and (b') is the point of covalent attachment to the hydroxyl or primary or secondary amine heteroatom of the camptothecin moiety (-C); and wherein formulas (a), (a') and (a") represent exemplary units, wherein T* is a heteroatom from the hydroxyl or primary or secondary amine functional group of the camptothecin moiety (-C); and wherein the wavy line adjacent to T* is the point of covalent attachment to the remainder of the camptothecin moiety. In these embodiments, the third spacer unit -E- can facilitate the release of the camptothecin moiety as the free drug.

[0299] In still other embodiments, the third spacer unit has the formula: Represented by TIFF2024540692000275.tif38128, wherein formula (a1) and formula (a1') where each R is independently -H or (C1-C4) alkyl represent units where O* is the oxygen atom from the hydroxyl substituent of the camptothecin moiety (-C); and the wavy lines in formula (a1), formula (a1') and formula (b1) retain their aforesaid meanings from formulas (a), (a') and (b), respectively. In formula (a1'), -CH2CH2N + The (R)2 moiety represents an exemplary basic unit in protonated form.

[0300] Without being bound by theory, Scheme 1b depicts the mechanism of free drug release from a camptothecin moiety connected to a methylene carbamate unit in a conjugate bearing a self-immolative moiety, where T* is a heteroatom from a hydroxyl or primary or secondary amine of the camptothecin moiety that is incorporated into the methylene carbamate unit. TIFF2024540692000276.tif77128

[0301] Camptothecin moiety (-C) The term "camptothecin moiety" includes camptothecin itself and analogs of camptothecin. Camptothecin is a topoisomerase poison discovered in 1966 by ME Wall and MC Wani in a systematic screening of natural products for anticancer drugs. Camptothecin was isolated from the bark and stem of Camptotheca acuminata (camptotheca, happy tree), a tree native to China used as a cancer treatment in traditional Chinese medicine. Camptothecin has the following structure: TIFF2024540692000277.tif25128. The term "campthothecin moiety" also includes camptothecin analogs. In this regard, the term "camptothecin moiety" refers to the structure of camptothecin: TIFF2024540692000278.tif25128, and optionally substituted. Optional substituents include, but are not limited to, (C1-C 10The camptothecin moiety may include, for example, a (C3-C8) alkyl, a (C3-C8) carbocyclo, a (C3-C8) heterocyclo, an aryl, an amino group, a hydroxy group, a carbonyl group, an amide group, an ester group, a carbamate group, a carbonate group, and / or a silyl group. The camptothecin moiety may have one or more functional groups capable of forming a bond to the linker L. One skilled in the art would readily select a suitable camptothecin moiety having the desired biological activity. For example, camptothecin analogs such as topotecan, irinotecan, or belotecan are currently approved and used in cancer chemotherapy.

[0302] The following camptothecin analogs are also contemplated by the term camptothecin moiety: TIFF2024540692000279.tif251163 Further camptothecin analogues that can be used as the camptothecin moiety are described in WO 2019 / 236954 and EP 0 495 432.

[0303] In some embodiments, the camptothecin moiety (C) is selected from the group consisting of exatecan, SN38, camptothecin, topotecan, irinotecan, belotecan, lurtotecan, rubitecan, siratecan, cositecan, and gimatecan. Preferably, the camptothecin moiety is selected from the group consisting of exatecan, SN38, camptothecin, topotecan, irinotecan, and belotecan. SN38 has the following structure: TIFF2024540692000280.tif22128; the structures of exatecan, camptothecin, topotecan, irinotecan and belotecan are as described herein.

[0304] More preferably, in any one of the embodiments described herein, the camptothecin moiety C has the following structure: Exatecan with TIFF2024540692000281.tif55128.

[0305] Even more preferably, the camptothecin moiety has the following structure: Exatecan with TIFF2024540692000282.tif55128.

[0306] Preferably, in any one of these embodiments, exatecan is attached to the linker L via an amino group (i.e., via the NH group of exatecan). Exatecan attached to the linker L via an amino group can be depicted, for example, as follows: TIFF2024540692000283.tif59163Here, # indicates the connection point to the linker L.

[0307] The present invention also relates to a conjugate having formula (I): TIFF2024540692000284.tif35128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: RBM is an antibody; TIFF2024540692000285.tif6128 is a double bond; or TIFF2024540692000286.tif6128 is a single bond; V is absent if TIFF2024540692000287.tif6128 is a double bond; or V is TIFF2024540692000288.tif6128 is a single bond, then H; X is TIFF2024540692000289.tif6128 is a double bond, then R3-C; or X is If TIFF2024540692000290.tif6128 is a single bond, TIFF2024540692000291.tif9128; Y is NH; R 1 The structure: TIFF2024540692000292.tif15128, where: TIFF2024540692000293.tif9128 indicates the position of O; K F is as defined herein; preferably K F is H; and o is an integer as defined herein; preferably o is an integer in the range of 8 to 30; more preferably 16 to 30; even more preferably 20 to 28; even more preferably o is 22, 23, 24, 25 or 26; even more preferably o is 23, 24 or 25; still more preferably o is 24; R 3 is H; R 4 is H; L has the following structure: TIFF2024540692000294.tif50128, where # indicates the point of attachment to Y and * indicates the point of attachment to the camptothecin moiety (C); C is a camptothecin moiety; m is 1; and n is an integer as defined herein; Preferably, n is an integer ranging from 1 to 10; more preferably from 2 to 10; even more preferably from 4 to 10; even more preferably from 6 to 10, even more preferably from 7 to 10, and still more preferably n is 8; or Preferably, n is an integer ranging from 1 to 10, more preferably from 2 to 8, even more preferably from 3 to 6, even more preferably n is 4 or 5, and even more preferably n is 4.

[0308] Preferably, the camptothecin moiety C has the following structure: Exatecan with TIFF2024540692000295.tif55128.

[0309] More preferably, the camptothecin moiety has the following structure: Exatecan with TIFF2024540692000296.tif55128.

[0310] Preferably, in any one of these embodiments, exatecan is attached to the linker L via an amino group.

[0311] The present invention also relates to a conjugate having the following formula (Ia): TIFF2024540692000297.tif73148 in formula: The RBM is an antibody; and n is an integer as defined herein; Preferably, n is an integer ranging from 1 to 10; more preferably from 2 to 10; even more preferably from 4 to 10; even more preferably from 6 to 10, even more preferably from 7 to 10, and still more preferably n is 8; or Preferably, n is an integer ranging from 1 to 10, more preferably from 2 to 8, even more preferably from 3 to 6, even more preferably n is 4 or 5, and even more preferably n is 4.

[0312] Compound of formula (II) The present invention also provides a compound having formula (II): TIFF2024540692000298.tif27128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: TIFF2024540692000299.tif6128 is a triple bond; or TIFF2024540692000300.tif6128 is a double bond; V is absent if TIFF2024540692000301.tif6128 is a triple bond; or V is TIFF2024540692000302.tif6128 is a double bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000303.tif6128 is a triple bond, then R3-C: or X is If TIFF2024540692000304.tif6128 is a double bond, TIFF2024540692000305.tif9128; Y is NR 5 , S, O, or CR 6 R 7 and; R 1 is an optionally substituted aliphatic or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10.

[0313] Preferably R 3 is H or (C1-C8) alkyl; more preferably R 3 is H. Preferably R 4 When present, R is H or (C-C) alkyl; more preferably R 4 When present, R is H. Preferably, R 5 When present, R is H or (C-C) alkyl; more preferably R 5When present, R is H. Preferably, R 6 When present, R is H or (C-C) alkyl; more preferably R 6 When present, R is H. Preferably, R 7 When present, R is H or (C-C) alkyl; more preferably R 7 is H, if present.

[0314] Preferably, TIFF2024540692000306.tif6128 is a triple bond; V is absent; X is R3-C; and R 3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 3 is H or (C1-C8) alkyl; more preferably R 3 is H.

[0315] More preferably, TIFF2024540692000307.tif6128 represents a triple bond; V is absent; X represents R-C, and R represents H or (C-C) alkyl. Preferably, R represents H or (C-C) alkyl, more preferably H or (C-C) alkyl, even more preferably H or (C-C) alkyl. Even more preferably, R 3 is H.

[0316] In some embodiments, TIFF2024540692000308.tif6128 can be a double bond; V is H or (C1-C8) alkyl, preferably V is H; X is TIFF2024540692000309.tif9128; R3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; more preferably R 3 is H or (C1-C8) alkyl, more preferably R 3 is H;R 4is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably, R 4 is H or (C-C) alkyl, preferably R 4 is H.

[0317] In some embodiments, TIFF2024540692000310.tif6128 may represent a double bond; V may be H or (C1-C8) alkyl; X may be TIFF2024540692000311.tif9128; and R3 and R4 may independently represent H or (C1-C8) alkyl. Preferably, R3 and R4 independently represent H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. Preferably, R3 and R4 are the same; even more preferably, R3, R4 and V are the same. More preferably, R3 and R4 are both H. Preferably, V is H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. Even more preferably, V is H. In a preferred embodiment, R3, R4 and V are each H.

[0318] In any one of the compounds of formula (II), the variables may be defined as described herein, particularly with respect to the conjugate of formula (I) and / or the thiol-containing molecule of formula (III). Thus, RBM, TIFF2024540692000312.tif6128, V, X, Y, R 1 , R 3 , R 4 , R 5 , R 6 , R 7 , L, D, m and n are as defined herein. Preferably, Y is NH.

[0319] Methods for preparing conjugates of formula (I) The present invention also relates to a method for preparing a conjugate of formula (I), said method comprising: Compounds of formula (II): TIFF2024540692000313.tif28128, or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: TIFF2024540692000314.tif6128 is a triple bond; or TIFF2024540692000315.tif6128 is a double bond; V is absent if TIFF2024540692000316.tif6128 is a triple bond; or V is TIFF2024540692000317.tif6128 is a double bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000318.tif6128 is a triple bond, then R3-C: or X is If TIFF2024540692000319.tif6128 is a double bond, TIFF2024540692000320.tif9128; Y is NR 5 , S, O, or CR 6 R 7 and; R 1 is an optionally substituted aliphatic or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 6is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10; a compound of formula (II) or a pharmaceutically acceptable salt or solvate thereof; A thiol-containing molecule of formula (III): TIFF2024540692000321.tif9128 formula, RBM is a receptor binding molecule; and n is an integer ranging from 1 to 20; a thiol-containing molecule of formula (III) By reacting A compound of formula (I) TIFF2024540692000322.tif36128 formula: TIFF2024540692000323.tif6128 is a compound of formula (II) TIFF2024540692000324.tif6128 is a triple bond if it is a double bond; or TIFF2024540692000325.tif6128 is a compound of formula (II) TIFF2024540692000326.tif6128 is a double bond, it is a single bond; V is absent if TIFF2024540692000327.tif6128 is a double bond; or V is TIFF2024540692000328.tif6128 is a single bond, then it is H or (C1-C8) alkyl; X is TIFF2024540692000329.tif6128 is a double bond, then R3-C; or X is If TIFF2024540692000330.tif6128 is a single bond, TIFF2024540692000331.tif9128; Y is NH, S, O, or CH; R 1 is an optionally substituted aliphatic or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20; A compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof The method includes the step of generating

[0320] Preferably R 3 is H or (C1-C8) alkyl; more preferably R 3 is H. Preferably, R 4 When present, R is H or (C-C) alkyl; more preferably R 4 When present, R is H. Preferably, R 5 When present, R is H or (C-C) alkyl; more preferably R5 When present, R is H. Preferably, R 6 When present, R is H or (C-C) alkyl; more preferably R 6 When present, R is H. Preferably, R 7 When present, R is H or (C-C) alkyl; more preferably R 7 is H, if present.

[0321] Preferably, TIFF2024540692000332.tif6128 is a triple bond; V is absent; X is R3-C; and R 3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 3 is H or (C1-C8) alkyl; more preferably R 3 is H; and TIFF2024540692000333.tif6128 represents a double bond.

[0322] More preferably, TIFF2024540692000334.tif6128 represents a triple bond; V is absent; X represents R3-C, where R3 represents H or (C1-C8) alkyl; and TIFF2024540692000335.tif6128 represents a double bond. Preferably, R3 represents H or (C1-C6) alkyl, more preferably H or (C1-C4) alkyl, even more preferably H or (C1-C2) alkyl. Even more preferably, R3 is H.

[0323] In some embodiments, TIFF2024540692000336.tif6128 can be a double bond; V is H or (C1-C8) alkyl, preferably V is H; X is TIFF2024540692000337.tif9128; R3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; and TIFF2024540692000338.tif6128 may represent a bond; more preferably R 3 is H or (C1-C8) alkyl, more preferably R 3 is H;R 4 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably, R 4 is H or (C-C) alkyl, preferably R 4 is H.

[0324] In some embodiments, TIFF2024540692000339.tif6128 may represent a double bond; V may be H or (C1-C8) alkyl; X may be TIFF2024540692000340.tif9128; R3 and R4 may independently represent H or (C1-C8) alkyl; and TIFF2024540692000341.tif6128 may represent a bond. Preferably, R3 and R4 independently represent H or C1-C6-alkyl, more preferably H or C1-C4-alkyl, even more preferably H or C1-C2-alkyl. Preferably, R3 and R4 are the same; even more preferably, R3, R4 and V are the same. More preferably, R3 and R4 are both H. Preferably, V is H or C1-C6-alkyl, more preferably H or C1-C4-alkyl, even more preferably H or C1-C2-alkyl. Even more preferably, V is H. In a preferred embodiment, R3, R4 and V are each H.

[0325] Expressions used in this specification TIFF2024540692000342.tif6128 and With respect to TIFF2024540692000343.tif6128, it should be noted that, as is commonly known to those skilled in the art, each carbon atom is tetravalent. Thus, the structure: TIFF2024540692000344.tif18128, where X and V are as defined herein and an asterisk (*) indicates the connection to phosphorus, has the structure: TIFF2024540692000345.tif23128, where R3, R4 and V are as defined herein. TIFF2024540692000346.tif19128, where X and V are as defined herein, the asterisk (*) indicates the connection to phosphorus, and the # indicates the connection to the receptor binding molecule (RBM), has the structure: TIFF2024540692000347.tif22128, where R, R, and V are as defined herein, and H is hydrogen. The wavy bond indicates that the configuration of the double bond may be E or Z. It is also possible that the compound exists as a mixture of E and Z isomers.

[0326] If the receptor-binding molecule, such as an antibody, contains one or more disulfide bridges, the method may further include reducing at least one disulfide bridge of the receptor-binding molecule in the presence of a reducing agent to form a thiol (SH) group. The resulting compound of formula (III) may then be reacted with a compound of formula (II) to produce a conjugate of formula (I). The reducing agent may be selected from the group consisting of tris(2-carboxyethyl)phosphine (TCEP), dithiothreitol (DTT), sodium dithionite, sodium thiosulfate, and sodium sulfite. Thus, the reducing agent may be dithiothreitol (DTT). The reducing agent may be sodium dithionite. The reducing agent may be sodium sulfite. Preferably, the reducing agent is tris(2-carboxyethyl)phosphine (TCEP).

[0327] Preferably, the reduction of at least one disulfide bridge comprises using about 1 to about 3 equivalents, preferably about 1 to about 2 equivalents, more preferably about 1 equivalent of reducing agent per disulfide bridge to be reduced. In this context, it should be noted that theoretically, one equivalent of reducing agent, particularly a reducing agent as described herein, is required to reduce one disulfide bridge to two thiol (SH) groups.

[0328] Preferably, the thiol-containing molecule of formula (III) is reacted with about 1 to about 4 equivalents, preferably about 1 to about 3 equivalents, more preferably about 1 to about 2 equivalents, and even more preferably about 1.5 equivalents of the compound of formula (II) per thiol group (SH).

[0329] Preferably, the reaction of the compound of formula (II) with the thiol-containing molecule of formula (III) is carried out in an aqueous medium.

[0330] Preferably, the reaction of the compound of formula (II) with the thiol-containing molecule of formula (III) is carried out under neutral pH or slightly basic conditions. Even more preferably, the reaction is carried out at a pH between 6 and 10. Even more preferably, the reaction is carried out at a pH between 7 and 9.

[0331] In any one of the methods, the variables may be defined as described herein, particularly with respect to the conjugate of formula (I) and / or the compound of formula (II). Thus, RBM, TIFF2024540692000348.tif9128, V, X, Y, R 1 , R 3 , R 4 , R 5 , R 6 , R 7 , L, D, m and n are as defined herein. Preferably, Y is NH.

[0332] Methods for preparing compounds of formula (II) are known in the art. As an illustrative example, compounds of formula (II) in which the group Y is NH can be prepared, for example, by using techniques and conditions such as those described in WO 2018 / 041985 A1, which is incorporated herein by reference, for example, the Staudinger phosphonite reaction. Compounds of formula (II) in which Y is S or O can be prepared, for example, by using techniques and conditions such as those described in WO 2019 / 170710, which is incorporated herein by reference. Compounds of formula (I ... CR can be prepared in a manner similar to that of compounds of formula (I) in which Y is S or O, as described in WO 2019 / 170710. 6 R 7 Compounds of formula (II), which are, as illustrative examples, can be prepared, for example, by substituting at the phosphorus atom with a suitable organometallic compound, such as a Grignard compound or an organolithium compound. Those skilled in the art will readily select suitable methods and conditions for preparing compounds of formula (II). The Examples section of the present disclosure also includes guidance on how to prepare or obtain compounds of formula (II) and / or conjugates of formula (I).

[0333] The present invention also relates to conjugates of formula (I) obtainable or obtained by any method of preparing a conjugate of formula (I) as described herein.

[0334] Pharmaceutical Compositions The present invention further relates to pharmaceutical compositions comprising the conjugate of formula (I).

[0335] A pharmaceutical composition may comprise a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is greater than 0 to about 14, preferably about 1 to about 14, more preferably about 2 to about 14, even more preferably about 4 to about 14, even more preferably about 5 to about 12, even more preferably about 6 to about 12, even more preferably about 7 to about 10, and still more preferably about 8. Thus, a pharmaceutical composition may comprise a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is greater than 0 to about 14. Preferably, a pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 1 to about 14. More preferably, a pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 2 to about 14. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 4 to about 14. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 5 to about 12. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 6 to about 12. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 6 to about 10. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties per receptor-binding molecule in the composition is about 8. When the receptor-binding molecule is, in some preferred embodiments, an antibody or antibody fragment, such average number is also designated the "average drug-antibody ratio (DARav)."In this context, one of skill in the art will understand that a composition may comprise a population of conjugates that may vary in the number of camptothecin moieties per receptor-binding molecule and may optionally include unconjugated receptor-binding molecules, resulting in an average number of camptothecin moieties per receptor-binding molecule.

[0336] A pharmaceutical composition can comprise a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is greater than 0 to about 14, preferably about 1 to about 14, more preferably about 1 to about 12, even more preferably about 2 to about 10, even more preferably about 2 to about 8, even more preferably about 2 to about 6, even more preferably about 3 to about 5, and still more preferably about 4. Thus, a pharmaceutical composition can comprise a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is greater than 0 to about 14. Preferably, a pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 1 to about 14. More preferably, a pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 1 to about 12. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 2 to about 10. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 2 to about 8. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 2 to about 6. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 3 to about 5. Even more preferably, the pharmaceutical composition comprises a population of conjugates of Formula (I), wherein the average number of camptothecin moieties C per receptor-binding molecule is about 4. In some preferred embodiments, when the receptor-binding molecule is an antibody or antibody fragment, such average number is also referred to as the "average drug-to-antibody ratio (DARav)."

[0337] The pharmaceutical composition may further comprise one or more pharmaceutically acceptable carriers. In certain embodiments, the term "pharmaceutically acceptable" means approved by a regulatory agency or other generally recognized pharmacopeia for use in animals, particularly humans. Pharmaceutically acceptable carriers are well known in the art and include, for example, aqueous solutions such as water, 5% dextrose, or physiological buffered saline, or other solvents or vehicles such as glycols, glycerol, oils such as olive oil, or injectable organic esters, suitable for administration to humans or non-human subjects. Certain exemplary pharmaceutically acceptable carriers include (biodegradable) liposomes; biodegradable polymer D,L-lactic acid-co-glycolic acid (PLGA) microspheres, albumin microspheres; synthetic polymers (soluble); nanofibers, protein-DNA complexes; protein conjugates; red blood cells; or virosomes. Various carrier-based dosage forms include solid lipid nanoparticles (SLNs), polymeric nanoparticles, ceramic nanoparticles, hydrogel nanoparticles, co-peptide nanoparticles, nanocrystals and nanosuspensions, nanocrystals, nanotubes and nanowires, functionalized nanocarriers, nanospheres, nanocapsules, liposomes, lipid emulsions, lipid microtubules / microcylinders, lipid microbubbles, lipospheres, lipopolyplexes, reverse lipid micelles, dendrimers, ethosomes, multicomposite ultrathin capsules, aquasomes, pharmacosomes, colloidosomes, niosomes, discomes, proniosomes, microspheres, microemulsions, and polymeric micelles. Other suitable pharmaceutically acceptable carriers and excipients are described, inter alia, in Remington's Pharmaceutical Sciences, 15 th Ed., Mack Publishing Co., New Jersey (1991) and Bauer et al., Pharmazeutische Technologie, 5 thEd., Govi-Verlag Frankfurt (1997). See, e.g., Remington: The Science and Practice of Pharmacy, 21 st See the full edition; Lippincott Williams & Wilkins, 2005.

[0338] In some embodiments, the pharmaceutically acceptable carrier or composition is sterile. In addition to the active ingredient, the pharmaceutical composition can contain physiologically acceptable compounds that act as, for example, bulking agents, fillers, solubilizers, stabilizers, osmotic agents, absorption enhancers, etc. Physiologically acceptable compounds include, for example, carbohydrates such as glucose, sucrose, lactose; dextran; polyols such as mannitol; antioxidants such as ascorbic acid or glutathione; preservatives; chelating agents; buffers; or other stabilizers or excipients.

[0339] The selection of a pharmaceutically acceptable carrier and / or physiologically acceptable compound may depend, for example, on the properties of the active agents, e.g., solubility, compatibility (meaning that the substances can be present together in the composition without interacting in a manner that substantially reduces the pharmaceutical effectiveness of the pharmaceutical composition under normal conditions of use), and / or the route of administration of the composition.

[0340] The pharmaceutical composition of the present invention contains a therapeutically effective amount of the conjugate of formula (I) described herein and can be configured in various forms, such as solid, liquid, gaseous, or lyophilized forms, particularly in the form of ointments, creams, transdermal patches, gels, powders, tablets, liquids, aerosols, granules, pills, suspensions, emulsions, capsules, syrups, solutions, elixirs, extracts, tinctures, or liquid extracts, or in a form particularly suitable for topical or oral administration.Various routes are applicable to the administration of the conjugate of formula (I), including, but not limited to, oral, topical, transdermal, subcutaneous, intravenous, intraperitoneal, intramuscular, or intraocular.However, those skilled in the art can easily select any other route as needed.

[0341] Use in methods of treatment As shown in the examples, the conjugate of formula (I) of the present invention can be used for treatment, particularly for the treatment of cancer. Accordingly, the present invention further relates to a conjugate of formula (I) of the present invention for use in a method for treating a disease, which optionally comprises administering an effective amount of the conjugate of the present invention or the pharmaceutical composition of the present invention to a subject or patient in need thereof. The present invention also relates to a pharmaceutical composition of the present invention for use in a method for treating a disease, which optionally comprises administering an effective amount of the conjugate of the present invention or the pharmaceutical composition of the present invention to a subject or patient in need thereof. The disease may be associated with overexpression of CD30. The disease may be associated with overexpression of Her2. The disease may be cancer. The cancer may be a solid tumor. The disease may be cancer associated with overexpression of CD30. The disease may be cancer associated with overexpression of Her2.

[0342] The present invention also relates to the use of a conjugate of formula (I) of the present invention for the manufacture of a medicament for treating a disease. The present invention also relates to the use of a pharmaceutical composition of the present invention for the manufacture of a medicament for treating a disease. The disease may be associated with overexpression of CD30. The disease may be associated with overexpression of Her2. The disease may be cancer. The cancer may be a solid tumor. The disease may be cancer associated with overexpression of CD30. The disease may be cancer associated with overexpression of Her2.

[0343] The present invention also relates to a method for treating a disease, comprising administering to a subject or patient in need thereof an effective amount of a conjugate of formula (I) of the present invention. The present invention also relates to a method for treating a disease, comprising administering to a subject or patient in need thereof an effective amount of a pharmaceutical composition of the present invention. The disease may be associated with overexpression of CD30. The disease may be associated with overexpression of Her2. The disease may be cancer. The cancer may be a solid tumor. The disease may be cancer associated with overexpression of CD30. The disease may be cancer associated with overexpression of Her2.

[0344] The phrase "effective amount" generally refers to an amount of a therapeutic agent (e.g., a conjugate of the invention) that, when used alone or in combination with another therapeutic agent, protects a subject from developing a disease or promotes disease regression as evidenced by a decrease in the severity of disease symptoms, an increase in the frequency and duration of disease symptom-free periods, or prevention of impairment or disability due to the disease affliction. The ability of a therapeutic agent to promote disease regression can be evaluated using a variety of methods known to those skilled in the art, such as in human subjects in clinical trials, in animal model systems predictive of efficacy in humans, or by assaying the activity of the agent in in vitro assays. The precise amount will depend on the purpose of the treatment and can be ascertained by one skilled in the art using known techniques (see, e.g., Lloyd (1999) The Art, Science and Technology of Pharmaceutical Compounding).

[0345] Furthermore, the present invention relates to a conjugate of formula (I) as described herein for use in a method for treating cancer in a patient. The present invention also relates to a pharmaceutical composition as described herein for use in a method for treating cancer in a patient. The term "patient" according to the present invention means a mammal, such as a human, a non-human primate, or another animal, particularly a cow,...

Claims

1. A conjugate having formula (I): or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: RBM is a receptor binding molecule; is a double bond; or is a single bond; V is is absent when is a double bond; or V is If is a single bond, H or (C 1 -C 8 ) alkyl; X is If is a double bond, R 3 -C; or X is If is a single bond, and Y is NR 5 , S, O, or CR 6 R 7 and R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20; A conjugate of formula (I), or a pharmaceutically acceptable salt or solvate thereof.

2. is a double bond; V is absent; X is R 3 -C; and R 3 is H or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; preferably R 3 is H or (C 1 -C 8 ) alkyl; more preferably R 3 The conjugate of claim 1, wherein

3. 2. The conjugate of claim 1, wherein the receptor-binding molecule is selected from the group consisting of an antibody, an antibody fragment, and a proteinaceous binding molecule with antibody-like binding properties.

4. 4. The conjugate of claim 3, wherein the receptor-binding molecule is an antibody.

5. 5. The conjugate of claim 4, wherein the antibody is selected from the group consisting of a monoclonal antibody, a chimeric antibody, a humanized antibody, a human antibody, and a single domain antibody, such as a camel or shark single domain antibody.

6. 2. The conjugate of claim 1, wherein Y is NH.

7. 7. The conjugate of claim 6, wherein the receptor-binding molecule is an antibody.

8. 2. The conjugate of claim 1, wherein the linker L is cleavable.

9. 9. The conjugate of claim 8, wherein the linker L is cleavable by a protease, glucuronidase, sulfatase, phosphatase, esterase, or by disulfide reduction.

10. 10. The conjugate of claim 9, wherein the linker L is cleavable by a protease, preferably by a cathepsin such as cathepsin B.

11. 2. The conjugate of claim 1, wherein the linker L comprises a valine-citrulline moiety or a valine-alanine moiety.

12. The linker L is and 12. The conjugate of claim 11, wherein # indicates the point of attachment to the Y and * indicates the point of attachment to the camptothecin moiety.

13. The linker L is and 12. The conjugate of claim 11, wherein * indicates the point of attachment to the Y and ## indicates the point of attachment to the camptothecin moiety.

14. R 1 is the first polyalkylene glycol unit R F 2. The conjugate of claim 1, wherein:

15. First polyalkylene glycol unit R F But the structure:

15. The conjugate of claim 14, comprising 1 to 100 subunits having the formula:

16. R F but, and where: indicates the position of O; K F -H, -PO 3 H, -(C 1 -C 10 ) alkyl, -(C 1 -C 10 )Alkyl-SO 3 H, -(C 2 -C 10 )Alkyl-CO 2 H, -(C 2 -C 10 ) alkyl-OH, -(C 2 -C 10 )Alkyl-NH 2 , -(C 2 -C 10 ) alkyl-NH(C 1 -C 3 ) alkyl and -(C 2 -C 10 ) alkyl-N((C 1 -C 3 )Alkyl) 2 and 16. The conjugate of claim 15, wherein o is an integer ranging from 1 to 100.

17. R 1 is the first polyethylene glycol unit.

18. First polyethylene glycol unit R F But the structure:

18. The conjugate of claim 17, comprising 1 to 100 subunits having the formula:

19. R F but, and where: indicates the position of O; K F -H, -PO 3 H, -(C 1 -C 10 ) alkyl, -(C 1 -C 10 )Alkyl-SO 3 H, -(C 2 -C 10 )Alkyl-CO 2 H, -(C 2 -C 10 ) alkyl-OH, -(C 2 -C 10 )Alkyl-NH 2 , -(C 2 -C 10 ) alkyl-NH(C 1 -C 3 ) alkyl and -(C 2 -C 10 ) alkyl-N((C 1 -C 3 )Alkyl) 2 and 19. The conjugate of claim 18, wherein o is an integer ranging from 1 to 100.

20. K F 20. The conjugate of claim 19, wherein is H.

21. 21. The conjugate of claim 20, wherein o is in the range of 8 to 30.

22. 22. The conjugate of claim 21, wherein o is in the range of 20 to 28.

23. 23. The conjugate of claim 22, wherein o is 22, 23, 24, 25 or 26.

24. 2. The conjugate of claim 1, wherein the camptothecin moiety C is selected from the group consisting of exatecan, SN38, camptothecin, topotecan, irinotecan, belotecan, lurtotecan, rubitecan, ciratecan, cositecan, and gimatecan.

25. The camptothecin moiety C has the formula:

25. The conjugate of claim 24, which is exatecan having the formula:

26. The camptothecin moiety C has the formula:

26. The conjugate of claim 25, which is exatecan having the formula:

27. 26. The conjugate of claim 25, wherein exatecan is attached to the linker L via an amino group.

28. the RBM is an antibody; is a double bond; or is a single bond; V, is absent when is a double bond; or V, is a single bond, then H; X is, If is a double bond, R 3 -C; or X is, If is a single bond, and Y is NH; R 1 But the structure: and a polyethylene glycol unit having the formula: where: indicates the position of O; K F is H; and o is an integer ranging from 8 to 30; R 3 is H; R 4 is H; L has the following structure: where # indicates the point of attachment to Y and * indicates the point of attachment to the camptothecin moiety (C); C is a camptothecin moiety; m is 1; and 2. The conjugate of claim 1, wherein n is an integer ranging from 1 to 10.

29. The camptothecin moiety C has the formula:

29. The conjugate of claim 28, which is exatecan having the formula:

30. 30. The conjugate of claim 29, wherein exatecan is attached to the linker L via an amino group.

31. 31. The conjugate of claim 30, wherein o is in the range of 20 to 28.

32. 32. The conjugate of claim 31, wherein o is 22, 23, 24, 25 or 26.

33. 29. The conjugate of claim 28, wherein n is in the range of 2 to 10, preferably n is 4 or 8.

34. The following formula (Ia): wherein the RBM is an antibody.

35. Compounds having formula (II): or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: is a triple bond; or is a double bond; V is is absent when is a triple bond; or V is If is a double bond, H or (C 1 -C 8 ) alkyl; X is If is a triple bond, R 3 -C; or X is If is a double bond, and Y is NR 5 , S, O, or CR 6 R 7 and R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10; A compound of formula (II) or a pharmaceutically acceptable salt or solvate thereof:

36. 1. A method for preparing a conjugate of formula (I), the method comprising: Compound of formula (II): or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: is a triple bond; or is a double bond; V is is absent when is a triple bond; or V is If is a double bond, H or (C 1 -C 8 ) alkyl; X is If is a triple bond, R 3 -C; or X is If is a double bond and Y is NR 5 , S, O, or CR 6 R 7 and R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; and m is an integer ranging from 1 to 10; a compound of formula (II) or a pharmaceutically acceptable salt or solvate thereof; A thiol-containing molecule of formula (III): During the ceremony, RBM is a receptor binding molecule; and n is an integer ranging from 1 to 20; a thiol-containing molecule of formula (III) By reacting Compounds of formula (I): or a pharmaceutically acceptable salt or solvate thereof, During the ceremony: is the compound of formula (II) is a double bond when is a triple bond; or is the compound of formula (II) is a single bond when is a double bond; V is is absent when is a double bond; or V is If is a single bond, H or (C 1 -C 8 ) alkyl; X is If is a double bond, R 3 -C; or X is If is a single bond, and Y is NR 5 , S, O, or CR 6 R 7 and R 1 is an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 3 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 4 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 5 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 6 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; R 7 is H; or an optionally substituted aliphatic residue or an optionally substituted aromatic residue; L is a linker; C is a camptothecin moiety; m is an integer ranging from 1 to 10; and n is an integer ranging from 1 to 20; A compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof The step of generating A method comprising:

37. reducing at least one disulfide bridge of the receptor-binding molecule in the presence of a reducing agent to form a thiol group (SH); 37. The method of claim 36, further comprising:

38. 35. A pharmaceutical composition comprising the conjugate of any one of claims 1 to 34.

39. 39. The pharmaceutical composition of claim 38, wherein the pharmaceutical composition comprises a population of the conjugates of any one of claims 1 to 27, and wherein the average number of camptothecin moieties C per receptor-binding molecule is greater than 0 to about 14.

40. 39. The pharmaceutical composition of claim 38 for use in a method of treating a disease.

41. 41. The pharmaceutical composition of claim 40, wherein the disease is cancer.

42. 42. The pharmaceutical composition of claim 41, wherein the cancer is a solid tumor.

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