Antibody-drug conjugate comprising an Anti-pmel-17 antibody, and uses thereof

Abstract

The present invention relates in general to the field of medicine. More particularly, it relates to new antibody-drug conjugates and uses thereof.

Description

[0001] ANTIBODY-DRUG CONJUGATE INCLUDING AN ANTI-PMEL-17 ANTIBODY AND ITS USES

[0002] FIELD OF INVENTION

[0003] The present invention relates generally to the field of medicine. More particularly, it relates to novel antibody-drug conjugates and their uses.

[0004] PREVIOUS ART

[0005] Premelanosome protein (PMEL or PMEL17), also known as silver locus protein homolog (SILV) or Glycoprotein 100 (gp100), makes up the fibers of premelanosomes. It is encoded by the PMEL gene, which is also called silver, ME20, gp100, or PMEL17.

[0006] PMEL17 is a type I transmembrane protein that passes through endosomes (stage I premelanosomes). In these organelles, PMEL17 is cleaved by a furin convertase as well as other proteases. The luminal domains of PMEL17 thus released self-assemble and form fibers that organize into amyloid sheets (Hurbain I, Proc Natl Acad Sci USA 2008; 105: 19726-19731).

[0007] The expression of PMEL17 on melanosomes is regulated by an oncogene, MITF (Microphthalmia-associated transcription factor). 1 It is upregulated in a variety of primary and metastatic tumors, including cutaneous and uveal melanomas. Transient cell-surface expression and internalization of PMEL17, along with the PMEL-17 expression ratio between healthy tissues and tumors, make it a suitable target for the development of an antibody-drug conjugate (ADC).

[0008] The PMEL / NMB family consists of two members, PMEL17 and GPNMB. It has attracted interest as a family of therapeutic targets in cancer, glaucoma, and certain neurodegenerative diseases (Paul W. Chrystal, Molecules. 2021 Jun; 26(12): 3529).

[0009] Furthermore, Tebentafusp was recently the first approved drug to demonstrate a survival benefit in patients with metastatic uveal melanoma. Its use, however, remains limited to HLA-A2*02:01 positive patients, who represent 50% of Caucasians. It is a bispecific protein, consisting of a T-cell receptor (TCR) targeting the PMEL17 peptide presented by HLA-A2*02:01 and a domain engaging anti-CD3 T cells. PMEL17, a melanocyte-specific glycoprotein, is widely expressed by uveal melanoma (UV) cells, up to 100% in primary and metastatic uveal melanoma (UM). Tebentafusp acts by redirecting T cells to tumor cells expressing PMEL17. As previously stated, the use of Tebentafusp is limited only to HL1-A2*02:01 positive patients who represent 50% of the total population.

[0010] Thus, targeting PMEL17 (or gp100), expressed on the surface of cancer cells, particularly melanoma cells, using an antibody-drug conjugate (ADC), appears especially relevant in human clinical biology as a therapeutic tool for targeting these tumor cells. However, in the arsenal of passive cancer immunotherapy using monoclonal antibodies, no ADC has yet proven effective in providing a therapeutic solution for all HLA-A2*02:01 positive and negative patients.

[0011] Moreover, while ADCs seem a promising therapeutic tool, some are very toxic, others have poor pharmacokinetics, still others have a limited therapeutic index reducing their clinical efficacy, and a large proportion of them use classic microtubule agents which face resistance mechanisms, especially in indications that are poorly or not at all responsive to chemotherapy.

[0012] To fill this therapeutic gap and meet the needs of patients, the inventors have therefore set themselves the goal of obtaining an optimized antibody-drug conjugate (ADC) capable of targeting PMEL17 on the surface of cancer cells and causing their cell death with little or no skin toxicity.

[0013] BRIEF OVERVIEW OF THE INVENTION

[0014] Faced with the major challenge of developing safe and effective cancer-fighting tools, the inventors have developed new, optimized antibody-drug conjugates (ADCs). A primary objective of the invention is to make a new ADC available to all HLA-A2*02:01 positive or negative patients. A secondary objective is to offer this ADC for use as a drug, particularly in the prevention and / or treatment of solid or hematological tumors. A further objective is to provide a pharmaceutical composition comprising the ADC of the invention, as well as its use in the diagnosis, prevention, and / or treatment of localized or metastatic tumors.

[0015] DETAILED DESCRIPTION

[0016] In its most general aspect, the invention relates to an antibody-drug conjugate (ADC) comprising the formula (I):

[0017] (I), in which:

[0018] ■ Ac is an anti-PMEL17 antibody, one of its fragments or one of its derivatives;

[0019] ■ TC is a conjugation head chosen from: maleimide coupled to glutamic acid (Mal-Glu), polyether, amino acids, benzyl group, amines and ketones;

[0020] ■ B represents "PEG2-Glu-(Glu-Met)" and is either absent or present;

[0021] ■ L is a linker cleavable by lysosomal cathepsins, said cleavable linker possibly being coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives;

[0022] ■ M is a drug chosen from: topoisomerase inhibitors, alkylating agents, antimicrotubule agents and their prodrug forms; and

[0023] ■ AS is a solubilizing agent selected from: polysarcosine (PSAR) and polyethylene glycol (PEG), and in which the drug-antibody ratio (DAR) is between 2 and 16 and said anti-PMEL17 comprises:

[0024] ■ a lightweight chain comprising from the N-terminal end to the C-terminal end:

[0025] - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1);

[0026] - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and

[0027] - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and

[0028] ■ a heavy chain comprising from the N-terminal end to the C-terminal end:

[0029] - CDR1, whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4); - CDR2, whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and

[0030] - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

[0031] Unexpectedly, the inventors determined that a synergy exists between the different components of the antibody-drug conjugate of the invention, which promotes improved bioavailability and increased stability. This results in a significant reduction in the unwanted release of the drug into a healthy (i.e., non-tumor) environment, thus preventing adverse effects. Surprisingly, the inventors also demonstrated that the concentration of the antibody-drug conjugate of the invention in tumors was well above what was expected. By developing the antibody-drug conjugate as described above, the inventors have therefore provided the medical community with a new, innovative, safe, and effective therapeutic tool for fighting cancer.

[0032] According to another embodiment, the invention relates to the antibody-drug conjugate (ADC) as described above comprising formula (II):

[0033] Ar-TC-l -M

[0034] AS

[0035] (ii), in which:

[0036] ■ Ac is an anti-PMEL17 antibody, one of its fragments or one of its derivatives;

[0037] ■ TC is a conjugation head chosen from: maleimide coupled to glutamic acid (Mal-Glu), polyether, amino acids, benzyl group, amines and ketones;

[0038] ■ L is a linker cleavable by lysosomal cathepsins, said cleavable linker possibly being coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives;

[0039] ■ M is a drug chosen from: topoisomerase inhibitors, alkylating agents, antimicrotubule agents and their prodrug forms; and

[0040] ■ AS is a solubilizing agent selected from: polysarcosine (PSAR) and polyethylene glycol (PEG), and in which the drug-antibody ratio (DAR) is between 2 and 16 and said anti-PMEL17 comprises:

[0041] ■ a light chain comprising from the N-terminal end to the C-terminal end: - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1);

[0042] - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and

[0043] - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and

[0044] ■ a heavy chain comprising from the N-terminal end to the C-terminal end:

[0045] - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4);

[0046] - CDR2, whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and

[0047] - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

[0048] The term "medicine (M)" refers to any substance or composition presented as having curative or preventive properties with respect to human or animal diseases. In the invention, this is selected from among: topoisomerase inhibitors, alkylating agents, antimicrotubule agents, and their prodrug forms. Examples of topoisomerase I inhibitors include irinotecan, topotecan, camptothecin, SN38, exatecan, silatecan, cositycan, lurtotecan, gimatecan, bleotecan, and rubitecan. Examples of alkylating agents include dacarbazine. Examples of antimicrotubule agents include the taxane family, notably paclitaxel. As mentioned above, this drug may be in a prodrug form, that is, an inactive form which, after administration, is converted by the body into a pharmacologically active drug.In the invention, the drug is in particular Exatecan and its prodrug forms, among which may be mentioned salts, esters, ethers, glucuronides, galactamines, cyclodextrins, and amides of Exatecan. Among its prodrug forms of Exatecan, Dxd (Exatecan derivative) is one of the best known.

[0049] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, wherein M is a drug selected from: exatecan and its prodrug forms (e.g., Dxd). In particular, the invention relates to the antibody-drug conjugate as described above, wherein M is exatecan.

[0050] The term "antibody (Ab)" refers to an immunoglobulin, which is a glycoprotein comprising at least two heavy chains (H) and at least two light chains (L) linked by one or more disulfide bonds. Each heavy chain comprises a variable region (or domain) (VH) and a constant region comprising three domains, usually designated CH1, CH2, and CH3. Each light chain comprises a variable region (or domain) (VL) and a constant region comprising a single domain, usually designated CL. The variable regions of the heavy and light chains involved in antigen recognition can be further subdivided into three hypervariable regions, also called complementarity-determining regions (CDRs), flanked by four more conserved regions, also called framework regions (FRs).The organization of each variable region of the heavy (or light) chain, from the N-terminus to the C-terminus, is as follows: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. The three-dimensional folding of these variable regions is such that all six CDRs are exposed on the same side of the protein, allowing the formation of a specific structure that recognizes a particular antigen. Furthermore, the term "antibody" in the context of the present invention includes not only complete antibody molecules but also fragments and derivatives thereof. "Antibody fragment" in the context of the present invention means either a monovalent fragment with a single antigen-binding site or a divalent fragment with two antigen-binding sites. Thus, a fragment according to the invention has at least one antigen-binding site.Among these fragments are Fab, F(ab')2, Fv, and other fragments that retain the antigen-binding site (scFv and diabody). A Fab fragment is a monovalent fragment consisting of the entire light chain and a portion of the heavy chain (Fd), including the VH and CH1 domains as previously defined. An F(ab')2 fragment is a divalent fragment resulting from the association of two Fab fragments linked by disulfide bonds in the immunoglobulin hinge region located between the CH1 and CH2 constant domains. An Fv fragment is a monovalent fragment consisting solely of the VL and VH variable regions of the light and heavy chains of an antibody. An scFv fragment is a monovalent polypeptide fragment, obtained only through genetic engineering, corresponding to the variable domains linked by a peptide bond.A diabody is a recombinant, divalent antibody molecule composed of two scFv molecules arranged head-to-tail due to a peptide bond too short to allow the formation of a single scFv. The fragments according to the invention also include fragments as previously mentioned whose half-life has been increased by chemical modification, notably by incorporation into a liposome or by the introduction of a poly(alkylene) glycol such as polyethylene glycol (PEG). This technique is called "PEGylation" and yields fragments such as Fab-PEG, F(ab')2-PEG, or Fv-PEG. Recombinant fragments of the antibody according to the present invention can also be generated by means of recombinant technology, either alone or fused, exhibiting more effective and better-controlled solid tumor penetration and pharmacokinetic properties. The antibody fragments useful within the scope of the present invention may be natural or recombinant.For the purposes of this invention, "antibody derivative" means antibody fragments obtained by genetic engineering, such as single-chain Fv (scFv) molecules and single-domain antibodies (dAbs). The term also includes antibody-type molecules that can be produced using phage display techniques or other random selection techniques and humanized mice, such as Harbour Mice® technology. Thus, "antibody fragments" and "antibody derivatives" encompass all molecules containing a structure, advantageously peptide, that forms part of the recognition site (i.e., the portion of the antibody that binds to or combines with the epitope or antigen) of an antibody according to the present invention.In particular and according to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 fragment is chosen from the group of fragments consisting of: Fv, Fab, F(ab')2, Fab', dsFv, scFv, sc(Fv)2, "diabodies".

[0051] As mentioned above, the invention implements an antibody, a fragment thereof, or a derivative thereof, capable of recognizing the PMEL17 receptor (SEQ ID NO: 17). Among them, the following antibody may be cited: SKM300 (also known as 17A9), the sequences of which are summarized in Table 1 below. Table 1. Anti-PMEL17 & corresponding sequences, aa: amino acid; nt: nucleotide.

[0052] An antibody-drug conjugate (ADC) is a complex molecule composed of an antibody bound to a payload or a biologically active cytotoxic (anticancer) drug. Antibody-drug conjugates are examples of bioconjugates and immunoconjugates and are a class of biopharmaceutical drugs designed primarily for targeted therapy for the prevention and / or treatment of cancer. Unlike chemotherapy, ADCs are designed to target and kill tumor cells while sparing healthy cells. In fact, ADCs combine the targeting capabilities of monoclonal antibodies with the cancer-killing capabilities of cytotoxic drugs, and are thus designed to distinguish between healthy and diseased tissues.

[0053] To obtain the antibody-drug conjugate, different molecules are used to create the covalent link between the antibody on one side and the drug on the other. Among these molecules are: the bioconjugation head (also called spacer or connector), a linker (which can be coupled to the leaving group p-aminobenzyl alcohol (PAB) or one of its derivatives) and a solubilizing agent.

[0054] The term "bioconjugation head" refers to maleimide coupled to glutamic acid (Mal-Glu), polyethers, amino acids, benzyl groups, amines, and ketones. Advantageously, it refers to maleimide coupled to glutamic acid (Mal-Glu). According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which TC is a maleimide conjugation head coupled to glutamic acid (Mal-Glu).

[0055] In the invention, "linker (L)" refers to a short chain of amino acids cleavable by lysosomal cathepsins, selected from: the dipeptide Val-Cit, the dipeptide Phe-Lys, the dipeptide Val-Ala, the tripeptide Ala-Ala-Asn, and the quadripeptide Gly-Gly-Phe-Gly, each of these linkers optionally being coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives. In particular, these are the dipeptides Phe-Lys and Val-Ala, which are advantageously coupled to PAB to form the linkers Phe-Lys-PAB and Val-Ala-PAB. According to another embodiment, the invention therefore relates to the antibody-drug conjugate as described above, in which L is a linker, in particular coupled to p-aminobenzyl alcohol (PAB), chosen from: the dipeptide Phe-Lys and the dipeptide Val-Ala.In particular, the invention relates to the antibody-drug conjugate as described above, in which L is a linker coupled to p-aminobenzyl alcohol (PAB) selected from: Phe-Lys-PAB and Val-Ala-PAB.

[0056] Note that between the bioconjugation head and the linker, an element B representing "PEG2-GIU- (Glu-Met)" can be added. Element B may therefore be absent or present in the ADC of the invention.

[0057] In the invention, "solubilizing agent (SA)" means either polysarcosine (PSAR) or polyethylene glycol (PEG).

[0058] Regarding the PSAR, it can be a monomer or a polymer with a number of PSARs ranging from 2 to 40, in particular from 8 to 24 and advantageously from 10 or 16. The polymer can nevertheless comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 PSARs. According to another embodiment, the invention therefore relates to the antibody-drug conjugate as described above, in which AS is polysarcosine (PSAR) either in the form of a monomer or in the form of a polymer whose number of PSARs varies from 2 to 40. In particular, the invention relates to the antibody-drug conjugate as described above, in which AS is polysarcosine (PSAR) in the form of a polymer whose number of PSARs is 10.

[0059] Regarding PEG, it can be a monomer or a bi-branched, tri-branched, cyclic or linear polymer with a number of PEGs ranging from 2 to 40, in particular from 8 to 24 and advantageously from 10 or 16. The polymer can nevertheless comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 PEGs. According to another embodiment, the invention therefore relates to the antibody-drug conjugate as described above, in which AS is polyethylene glycol (PEG) either in the form of a monomer or in the form of a bi-branched, tri-branched, cyclic or linear polymer whose number of PEGs varies from 2 to 40. In particular, the invention relates to the antibody-drug conjugate as described above, in which AS is polyethylene glycol (PEG) in the form of a bi-branched polymer whose number of PEGs is 10 or 16.

[0060] The "drug-antibody ratio (DAR)" refers to the average number of drugs conjugated to antibodies. In the invention, this ratio ranges from 2 to 16 and is particularly 2, 4, or 8 to 16, and is advantageously 8. In other words, the drug-antibody ratio (DAR) in the invention can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. In light of the foregoing, it is understood that, according to another embodiment, the invention relates to the antibody-drug conjugate as described above, said antibody-drug conjugate comprising formula (III):

[0061] Ac-[Mal-Glu]-BLM

[0062] AS

[0063] (nor), in which:

[0064] ■ Ac is an anti-PMEL17 antibody, one of its fragments or one of its derivatives;

[0065] ■ Mal-Glu is a maleimide conjugation head coupled to glutamic acid;

[0066] ■ B represents "PEG2-Glu-(Glu-Met)" and is either absent or present;

[0067] ■ L is a linker cleavable by lysosomal cathepsins, said cleavable linker being chosen from: the dipeptide Val-Cit, the dipeptide Phe-Lys, the dipeptide Val-Ala, the tripeptide Ala-Ala-Asn and the quadripeptide Gly-Gly-Phe-Gly, each of these linkers being optionally coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives;

[0068] ■ M is a drug chosen from: irinotecan, topotecan, camptothecin, SN38, exatecan, silatecan, cositycan, lurtotecan, gimatecan, bleotecan, rubitecan, dacarbazine, paclitaxel and their prodrug forms; and

[0069] ■ AS is a solubilizing agent selected from: polysarcosine (PSAR) and polyethylene glycol (PEG), and in which the drug-antibody ratio (DAR) is between 2 and 16 and said anti-PMEL17 comprises:

[0070] ■ a lightweight chain comprising from the N-terminal end to the C-terminal end:

[0071] - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1);

[0072] - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and

[0073] - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and

[0074] ■ a heavy chain comprising from the N-terminal end to the C-terminal end:

[0075] - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4);

[0076] - CDR2 whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

[0077] It is also understood that, according to another embodiment, the invention therefore relates to the antibody-drug conjugate as described above, said antibody-drug conjugate comprising the formula (IV):

[0078] Ac-[Mal-Glu]-LM

[0079] AS

[0080] (IV), in which:

[0081] ■ Ac is an anti-PMEL17 antibody, one of its fragments or one of its derivatives;

[0082] ■ Mal-Glu is a maleimide conjugation head coupled to glutamic acid;

[0083] ■ L is a linker cleavable by lysosomal cathepsins, said cleavable linker being chosen from: the dipeptide Val-Cit, the dipeptide Phe-Lys, the dipeptide Val-Ala, the tripeptide Ala-Ala-Asn and the quadripeptide Gly-Gly-Phe-Gly, each of these linkers being optionally coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives;

[0084] ■ M is a drug chosen from: irinotecan, topotecan, camptothecin, SN38, exatecan, silatecan, cositycan, lurtotecan, gimatecan, bleotecan, rubitecan, dacarbazine, paclitaxel and their prodrug forms; and

[0085] ■ AS is a solubilizing agent selected from: polysarcosine (PSAR) and polyethylene glycol (PEG), and in which the drug-antibody ratio (DAR) is between 2 and 16 and said anti-PMEL17 comprises:

[0086] ■ a lightweight chain comprising from the N-terminal end to the C-terminal end:

[0087] - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1);

[0088] - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and

[0089] - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and

[0090] ■ a heavy chain comprising from the N-terminal end to the C-terminal end:

[0091] - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4);

[0092] - CDR2 whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

[0093] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, wherein L is a linker, in particular coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives, selected from: the dipeptide Phe-Lys and the dipeptide Val-Ala. In particular, the invention relates to the antibody-drug conjugate as described above, wherein L is a linker coupled to p-aminobenzyl alcohol (PAB) selected from: Phe-Lys-PAB and Val-Ala-PAB.

[0094] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, wherein M is a drug selected from: exatecan, dacarbazine, paclitaxel, and their prodrug forms. In particular, the invention relates to the antibody-drug conjugate as described above, wherein M is exatecan and its prodrug forms.

[0095] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which AS is polysarcosine (PSAR), said PSAR being in particular a monomer or a polymer in which the number of PSARs varies from 2 to 40 (advantageously 10). According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which AS is polyethylene glycol (PEG), said PEG being in particular a monomer or a bi-branched, tri-branched, cyclic, or linear polymer in which the number of PEGs varies from 2 to 40 (advantageously 10 or 16).

[0096] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-M)-PEGw of formula (V): or Mal-Glu-(Val-Ala-PAB-M)-PEGio of formula (VI):

[0097] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-M)-PEGi6 of formula (VII): or to Mal-Glu-(Val-Ala-PAB-M)-PEGi6 of formula (VIII):

[0098] (VIII).

[0099] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to the Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-M)-PSARio of formula (IX): (IX).

[0100] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to the Mal-Glu-(Phe-Lys-PAB-M)-PSAR n or Mal-Glu-(Val-Ala-PAB-M)-PSARn where n varies from 1 to 40.

[0101] In view of the foregoing, it is understood that, according to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to:

[0102] ■ Mal-Glu-(Phe-Lys-PAB-M)-PEGio of formula (V);

[0103] ■ Mal-Glu-(Val-Ala-PAB-M)-PEGio of formula (VI);

[0104] ■ Mal-Glu-(Phe-Lys-PAB-M)-PEGi6 of formula (VII);

[0105] ■ Mal-Glu-(Val-Ala-PAB-M)-PEGi6 of formula (VIII);

[0106] ■ Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-M)-PSARio of formula (IX);

[0107] ■ Mal-Glu-(Phe-Lys-PAB-M)-PSAR n where n varies from 1 to 40; or

[0108] ■ Mal-Glu-(Val-Ala-PAB-M)-PSAR n where n varies from 1 to 40.

[0109] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, wherein M is a drug selected from: exatecan and its prodrug forms (e.g., salts, esters, ethers, glucuronides, galactamines, cyclodextrins, and amides of exatecan). In particular, the invention relates to the antibody-drug conjugate as described above, wherein M is a drug selected from: exatecan and Dxd (Exatecan derivative). Advantageously, the invention relates to the antibody-drug conjugate as described above, wherein M is exatecan.

[0110] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGw of formula (X):

[0111] or to Mal-Glu-(Val-Ala-PAB-exatecan)-PEGw of formula (XI): Exatecan may be in a prodrug form. According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGi6 of formula (XII): or Mal-Glu-(Val-Ala-PAB-exatecan)-PEGi6 of formula (XIII):

[0112] Exatecan may be in a prodrug form.

[0113] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-exatecan)-PSARio of formula (XIV): Exatecan may be in a prodrug form.

[0114] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, wherein the anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PSAR n or to Mal-Glu-(Val-Ala-PAB-exatecan)- PSARn where n varies from 1 to 40, with exatecan possibly being in a prodrug form.

[0115] In view of the foregoing, it is understood that according to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments or one of its derivatives, is linked to: ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGw of formula (X);

[0116] ■ Mal-Glu-(Val-Ala-PAB-exatecan)-PEGw of formula (XI);

[0117] ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGi6 of formula (XII);

[0118] ■ Mal-Glu-(Val-Ala-PAB-exatecan)-PEGi6 of formula (XIII);

[0119] ■ Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-exatecan)-PSARio of formula (XIV); ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PSAR n where n varies from 1 to 40; or

[0120] ■ Mal-Glu-(Val-Ala-PAB-exatecan)-PSAR n where n varies from 1 to 40, with exatecan potentially being in a prodrug form. In particular, the invention relates to the antibody-drug conjugate as described above, in which the anti-PMEL17, one of its fragments, or one of its derivatives, is linked to:

[0121] ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGw of formula (X);

[0122] ■ Mal-Glu-(Val-Ala-PAB-exatecan)-PEGw of formula (XI);

[0123] ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGi6 of formula (XII);

[0124] ■ Mal-Glu-(Val-Ala-PAB-exatecan)-PEGi6 of formula (XIII);

[0125] ■ Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-exatecan)-PSARio of formula (XIV);

[0126] ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PSAR nwhere n varies from 1 to 40; or

[0127] ■ Mal-Glu-(al-Ala-PAB-exatecan)-PSAR n where n varies from 1 to 40.

[0128] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGi6 of formula (XII):

[0129] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17, one of its fragments or one of its derivatives, is linked to Mal-Glu-(Val-Ala-PAB-exatecan)-PEGi6 of formula (XIII): According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which the drug-antibody ratio (DAR) is from 4 to 16 or from 8 to 16, and is in particular 2, 4 or 8 or 16.

[0130] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises:

[0131] ■ a light chain comprising a variable region having at least 80% identity with the sequence SEQ ID NO: 7, said variable region comprising from the N-terminal end to the C-terminal end:

[0132] - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1);

[0133] - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and

[0134] - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and

[0135] ■ a heavy chain comprising a variable region having at least 80% identity with the sequence SEQ ID NO: 11, said variable region comprising from the N-terminal end to the C-terminal end:

[0136] - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4);

[0137] - CDR2, whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and

[0138] - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

[0139] By "percentage of identity," we mean the percentage determined by direct comparison of two oligonucleotide sequences (nucleic acid sequences), by determining the number of identical nucleotides between the two sequences, then dividing it by the number of nucleotides in the longer of the two sequences, and multiplying the result by 100. By "having at least 80% identity," we therefore mean that the aforementioned percentage of identity is at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or is 100%.In this regard, it should be noted that this definition applies to all embodiments of the invention, including when it involves a direct comparison of two polypeptide sequences (amino acid sequences). Furthermore, it is understood that sequences having at least 80% identity with a reference sequence retain the same properties and functions, or even have these properties and functions improved.

[0140] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises a light chain including a variable region of sequence SEQ ID NO: 7 and a heavy chain including a variable region of sequence SEQ ID NO: 11.

[0141] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises a heavy chain including mutations selected from:

[0142] ■ L234A / L235A (LALA);

[0143] ■ L234F / L235E / P331S (FES);

[0144] ■ L234F / L235Q / K322Q (FQQ);

[0145] ■ A330S / P331S;

[0146] ■ L234A / L235A / P329G (LALAPG);

[0147] ■ L234A / G237A;

[0148] ■ L234A / L235A / G237A;

[0149] ■ L234A / L235A / G237A / P238S / H268A / A330S / P330S;

[0150] ■ L234A / L235E;

[0151] ■ G236R / L328R; and

[0152] ■ L234A / L235A / K322A.

[0153] Advantageously, it should be noted that the introduction of these mutations silences the antibody-drug conjugate as described above and reduces non-specific binding to immune cells. The ADCC effector functions of the antibody are thus inhibited, preventing non-specific degradation and release of the payload after, for example, phagocytosis by macrophages.

[0154] According to another embodiment, the invention advantageously relates to the antibody-drug conjugate as described above, wherein said anti-PMEL17 comprises a heavy chain containing a LALA mutation. The term "LALA mutation" refers to the Leucine (L), Alanine (A) substitutions at the following positions: L234A / L235A (LALA). These substitutions reduce binding to the Fc receptors FcyRI, FcyRI1, and FcyRIII, as well as to complement C1q. This mutation is used to prevent activation of the Fc receptors. Moreover, many therapeutic antibodies using LALA mutations have been the subject of clinical trials (e.g. bimagrumab NCT01925209, cemiplimab NCT02383212, galcanezumab NCT03559257, progolimab NCT03912389, risankizumab NCT02684370, spesolimab NCT03482635, teplizumab NCT00385697).

[0155] According to another embodiment, the invention therefore relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises a light chain including a variable region of sequence SEQ ID NO: 7 and a heavy chain including a variable region of sequence SEQ ID NO: 11, said heavy chain in particular comprising a LALA mutation.

[0156] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises:

[0157] ■ a light chain having at least 80% identity with sequence SEQ ID NO: 9, said light chain comprising a variable region of sequence SEQ ID NO: 7, and

[0158] ■ a heavy chain having at least 80% identity with the sequence SEQ ID NO: 13, said heavy chain comprising a variable region of sequence SEQ ID NO: 11 and comprising in particular a LALA mutation.

[0159] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0160] In particular, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 comprises:

[0161] ■ a light chain with sequence SEQ ID NO: 9 and a heavy chain with sequence SEQ ID NO: 13; or

[0162] ■ a light chain with sequence SEQ ID NO: 9 and a heavy chain with sequence SEQ ID NO: 15.

[0163] Advantageously, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 (which can be encoded by the nucleic acid of sequence SEQ ID NO: 10) and a heavy chain of sequence SEQ ID NO: 13 or 15 (which can be respectively encoded by the nucleic acid of sequence SEQ ID NO: 14 or 16).

[0164] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PEG of formula (X), and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0165] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-(Val-Ala-PAB-exatecan)-PEG of formula (XI), and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0166] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGi6 of formula (XII), and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0167] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-(Val-Ala-PAB-exatecan)-PEGi6 of formula (XIII), and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0168] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-PEG2-Glu-(Glu-Met-PAB-(Val-Ala)-exatecan)-PSARio of formula (XIV), and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0169] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, in which said anti-PMEL17 is linked to Mal-Glu-(Phe-Lys-PAB-exatecan)-PSAR n or Mal-Glu-(al-Ala-PAB-exatecan)-PSAR n where n varies from 1 to 40, and in which said anti-PMEL17 is the SKM300 comprising a light chain of sequence SEQ ID NO: 9 and a heavy chain of sequence SEQ ID NO: 13 or 15.

[0170] According to another embodiment, the invention relates to the antibody-drug conjugate as described above, said antibody-drug conjugate being obtained using site-specific technologies known to those skilled in the art. Among these technologies are Synnafix, Mablink, Araris, Catalant, ThioBridge®, and BTG (β-transglutaminase). In particular, the invention relates to the antibody-drug conjugate as described above, said antibody-drug conjugate being obtained using the ThioBridge® site-specific technology, which allows the antibody and drug to be conjugated at the cysteine ​​residues of the antibody.

[0171] According to a second aspect of the invention, it relates to the antibody-drug conjugate as described above for its use as a drug.

[0172] According to another embodiment, the invention relates to the antibody-drug conjugate as described above for its use in the prevention and / or treatment of a tumor. It should be noted that the ADC of the invention can be used either as monotherapy or in combination with other treatment protocols (chemotherapy, radiotherapy, immunotherapy, etc.). Also, according to another embodiment, the invention relates to the antibody-drug conjugate (ADC) as described above for its use as described above, said ADC being used as monotherapy or in combination. The invention may therefore relate to a kit of parts comprising at least the antibody-drug conjugate as described above and another product (e.g., another ADC, an anti-tumor agent, etc.), and the use of this kit of parts for the simultaneous, separate, or sequential combined administration of said ADC and said other product.

[0173] According to another embodiment, the invention relates to the antibody-drug conjugate as described above for its use as described above in the prevention and / or treatment of a tumor in an adult (major) or in a child (minor; pediatrics).

[0174] According to another embodiment, the invention relates to the antibody-drug conjugate as described above for its use as described above in the prevention and / or treatment of a primary and / or metastatic solid tumor and / or relapse (i.e., reappearance of the primary tumor after a period of remission). In particular, the invention relates to the antibody-drug conjugate as described above for its use in the prevention and / or treatment of a primary solid tumor. In particular, the invention relates to the antibody-drug conjugate as described above for its use in the prevention and / or treatment of a metastatic solid tumor. In particular, the invention also relates to the antibody-drug conjugate as described above for its use in the prevention and / or treatment of a primary and metastatic solid tumor.Solid cancerous tumors, identifiable as a localized cluster of cells, are distinct from blood cancers, such as leukemias, in which the cancerous cells circulating in the blood or lymph are dispersed throughout the body. Solid tumors can develop in any tissue: skin, mucous membranes, bones, organs, etc. They are the most common, accounting for 90% of human cancers. There are two main types of tumors:

[0175] ■ Carcinomas originating from epithelial cells (skin, mucous membranes, glands). Examples: breast, lung, prostate, intestinal, liver cancers, etc.

[0176] • Sarcomas, less frequent, originate from cells of connective tissues (known as "support" tissues). Examples: cancers of bone, cartilage, etc.

[0177] According to another embodiment, the invention relates to the antibody-drug conjugate as described above for its use as described above in the prevention and / or treatment of melanoma, in particular primary and metastatic uveal melanoma.

[0178] According to another aspect of the invention, it relates to a pharmaceutical composition comprising the antibody-drug conjugate as described above (as an active principle or as an active substance) and a pharmaceutically acceptable vehicle.

[0179] According to the present invention, a "pharmaceutically acceptable vehicle" means any substance added to a pharmaceutically acceptable acid (PAA) according to the present invention to facilitate its transport, prevent its substantial degradation in said composition, and / or increase its half-life. Advantageously, such a pharmaceutically acceptable vehicle is sterile and pyrogen-free. It may consist of water, propylene glycol, vegetable oils, or other suitable organic solvents. It is chosen according to the type of application of the pharmaceutical composition of the invention and, in particular, according to its method of administration. Thus, the pharmaceutical composition according to the invention consists of at least one PAA according to the present invention in free form or as an adjunct salt with a pharmaceutically acceptable acid, either in its pure form or in a composition in which it is combined with any other pharmaceutically compatible product.

[0180] According to another embodiment, the invention relates to the pharmaceutical composition as described above in which said antibody-drug conjugate is at a (unit) dose of 1 to 1,000 mg or at a (unit) dose of 0.015 to 15 mg / kg (based on a 66.6 kg man). "From 1 to 1,000 mg" also means that the (unit) dose can range from 1 to 100 mg, from 1 to 200 mg, from 1 to 300 mg, from 1 to 400 mg, from 1 to 500 mg, from 1 to 600 mg, from 1 to 700 mg, from 1 to 800 mg, from 1 to 900 mg, from 100 to 1,000 mg, from 200 to 1,000 mg, from 300 to 1,000 mg, from 400 to 1,000 mg, from 500 to 1,000 mg, from 600 to 1,000 mg, from 700 to 1,000 mg, from 800 to 1,000 mg, from 900 to 1,000 mg, from 100 to 900 mg, from 200 to 800 mg, from 300 to 700 mg or from 400 to 600 mg. This also means that this (unit) dose can be 1 mg, 100 mg, 200 mg, 300 mg, 400 mg, 500 mg, 600 mg, 700 mg, 800 mg, 900 mg or 1000 mg.

[0181] "From 0.015 to 15 mg / kg" also means that the (unit) dose can range from 0.015 to 1.5 mg / kg, from 0.015 to 3 mg / kg, from 0.015 to 4.5 mg / kg, from 0.015 to 6 mg / kg, from 0.015 to 7.5 mg / kg, from 0.015 to 9 mg / kg, from 0.015 to 10.5 mg / kg, from 0.015 to 12 mg / kg, from 0.015 to 13.5 mg / kg, from 1.5 to 15 mg / kg, from 3 to 15 mg / kg, from 4.5 to 15 mg / kg, from 6 to 15 mg / kg, from 7.5 to 15 mg / kg, from 9 to 15 mg / kg, from 10.5 to 15 mg / kg, 12 to 15 mg / kg, 13.5 to 15 mg / kg, 1.5 to 13.5 mg / kg, 3 to 12 mg / kg, 4.5 to 10.5 mg / kg or 6 to 9 mg / kg. This also means that this (unit) dose can be 0.015 mg / kg, 1.5 mg / kg, 3 mg / kg, 4.5 mg / kg, 6 mg / kg, 7.5 mg / kg, 9 mg / kg, 10.5 mg / kg, 12 mg / kg, 13.5 mg / kg or 15 mg / kg.

[0182] According to another aspect of the invention, it relates to the pharmaceutical composition as described above for use in the prevention and / or treatment of a tumor. It should be noted that the pharmaceutical composition of the invention can be used either as monotherapy or in combination with other pharmaceutical compositions from other treatment protocols (chemotherapy, radiotherapy, immunotherapy, etc.). Furthermore, and according to another embodiment, the invention relates to the pharmaceutical composition as described above for its use as described above, said pharmaceutical composition being used as monotherapy or in combination. The invention may therefore relate to a kit-of-parts comprising at least the pharmaceutical composition as described above and another pharmaceutical composition (e.g., comprising another ADC [i.e., different from that of the invention], an anti-tumor agent, etc.).), and the use of this kit-of-parts for the simultaneous, separate or sequential combined administration of said pharmaceutical composition as described above and said other pharmaceutical composition.

[0183] According to another embodiment, the invention relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of a tumor in an adult (major) or in a child (minor; pediatrics).

[0184] According to another embodiment, the invention relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of a primary and / or metastatic solid tumor and / or relapse (i.e., reappearance of the primary tumor after a period of remission). In particular, the invention relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of a primary solid tumor. In particular, the invention relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of a metastatic solid tumor.In particular, the invention also relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of a primary and metastatic solid tumor.

[0185] According to another embodiment, the invention relates to the pharmaceutical composition as described above for its use as described above in the prevention and / or treatment of melanoma, in particular primary and metastatic uveal melanoma.

[0186] According to another embodiment, the invention relates to the pharmaceutical composition as described above for its use as described above, said pharmaceutical composition being in a form suitable for administration: by systemic route; by local route; by parenteral route (for example intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intrasternal, intracranial, intramuscular or subcutaneous); by intratumoral route; by topical route; by rectal route; by intranasal route or by inhalation.

[0187] Examples of sterile compositions suitable for parenteral administration include aqueous or non-aqueous solutions, suspensions, and emulsions. Water, propylene glycol, vegetable oils, or other suitable organic solvents may be used as solvents or vehicles. These compositions may also contain adjuvants, such as wetting agents, isotonic agents, emulsifiers, etc. Compositions suitable for topical administration may include, for example, creams, lotions, mouthwashes, nasal or eye drops, or aerosols. Advantageously, the invention relates to the pharmaceutical composition as described above for its use as described above, said pharmaceutical composition being in a form suitable for administration by one of the following routes: parenteral, injectable, intratumoral, topical, inhalation, subcutaneous, nasal, intratumoral, or pulmonary.

[0188] According to this same aspect, the invention alternatively relates to a method of prevention and / or treatment of a solid tumor comprising administering to a patient in need an effective amount of the antibody-drug conjugate as described above, or of the pharmaceutical composition as described above.

[0189] In all respects, it should be noted that the various aspects of the invention, as well as its various embodiments, are interdependent. They can therefore be combined as many times as necessary to obtain preferred aspects and / or embodiments of the invention not explicitly described. This also applies to all the definitions provided in this description, which apply to all aspects of the invention and its embodiments.

[0190] In addition, the present invention is illustrated, but not limited to, by the following figures and examples.

[0191] LIST OF FIGURES

[0192] Figure 1. Transcriptomic analysis of the expression of the gene encoding PMEL17 in healthy tissues.

[0193] Figure 2. Transcriptomic analysis of HER-2 encoding gene expression in healthy tissues.

[0194] Figure 3. Transcriptomic analysis of the expression of the gene encoding NECTIN-4 in healthy tissues.

[0195] Figure 4. Transcriptomic analysis of TROP-2 gene expression in healthy tissues. Figure 5. Comparative 1 / 3 transcriptomic analysis of PMEL17 gene expression against clinically approved targets in solid tumors (HER-2, TROP-2, and NECTIN-4) for the ADC approach.

[0196] Figure 6. Comparative 2 / 3 transcriptomic analysis of the expression of the gene encoding PMEL17 with respect to clinically approved targets in solid tumors (HER-2, TROP-2 and NECTIN-4) for the ADC approach.

[0197] Figure 7. Comparative 3 / 3 transcriptomic analysis of the expression of the gene encoding PMEL17 with respect to clinically approved targets in solid tumors (HER-2, TROP-2 and NECTIN-4) for the ADC approach.

[0198] Figure 8. Comparative transcriptomic analysis of the expression of the gene encoding PMEL17 with respect to clinically approved targets and / or clinically under-evaluated targets for the ADC approach in hematological tumors (CD20, CD30, CD33, CD38, BCMA and GPCR20).

[0199] Figure 9. Transcriptomic analysis of tumor expression of the gene encoding PMEL17 in patient xenograft (PDX) tumor models.

[0200] Figure 10. Analysis of antibody purity by gel electrophoresis under reducing and non-reducing conditions.

[0201] Line M: Protein marker of molecular weight (kDa).

[0202] Line R: Antibody migration after treatment under reducing conditions.

[0203] NR line: Antibody migration after treatment under non-reducing conditions.

[0204] Figure 11. Monomeric purity analysis of the antibody by size exclusion chromatography (SEC-HPLC) in high-performance liquid chromatography.

[0205] Figure 12. Analysis of the monomeric purity of ADC by SEC-HPLC at a wavelength of 280 nM.

[0206] Figure 13. Analysis of the DAR (drug-antibody ratio) by liquid chromatography coupled with mass spectrometry and ultraviolet spectrophotometry at a wavelength of 280 nm (UV / LC-MS).

[0207] Figure 14. PMEL17 protein expression in melanoma cell lines (SK-MEL-5, SK-MEL-3, SK-MEL-28, MEW0, and IGR37). Figure 15. In vitro cytotoxicity studies in melanoma models (SK-MEL-5, SK-MEL-28, and IGR-37).

[0208] EXAMPLES

[0209] EXAMPLE No. 1 - Transcriptomic analysis of PMEL17 expression

[0210] MATERIALS & METHODS

[0211] Transcriptomic analysis

[0212] The expression of genes encoding PMEL17, HER-2, TROP-2 and NECTIN-4 was analyzed in healthy tissues of lungs, brains, keratinocytes, ovary, hepatocytes, kidneys, mammary glands, colon, prostate, cervix, thyroid gland, bladder and pancreas.

[0213] The expression of the gene encoding PMEL17 was analyzed in patient xenograft tumor (PDX) models from the LIDE platform in the following indications: Bladder cancer (BLCA); Brain cancer; Breast cancer (BRCA); Esophagogastric junction carcinoma; Cervical cancer (CESC); Cholangiocarcinoma; Colorectal cancer; Duodenal cancer; Endometrial cancer (UCEC); Esophageal cancer (ESCA); Gallbladder cancer (CHOL); Stomach cancer (STAD); Gastrointestinal stromal tumor; Hepatoblastoma; Leukemia (LAML); Liver cancer (LIHC) and Lung cancer (LUAD).

[0214] Bioinformatics analysis

[0215] A comparative bioinformatic analysis of the expression of the gene encoding PMEL17 with respect to the genes of some clinically validated targets for the ADC approach (HER-2, TROP-2 and NECTIN-4) was performed using the TCGA database in the following indications: Adrenal corticosteroid cancer (ACC), Bladder cancer (BLCA), Endometrioid cancer (UCEC), Melanoma (SKCM), Head and neck cancer (HNSC); Prostate cancer (PRAD); Renal papillary cell carcinoma (KIRP); Pancreatic cancer (PAAD); Sarcoma (SARC); Cervical cancer (CECS); Colon cancer (COAD); Squamous cell carcinoma of the lung (LUSC); Rectal cancer (READ); Clear cell renal cell carcinoma (Kl RC); Liver cancer (LIHC), Breast cancer (BRCA); Ovarian cancer (OV); Uterine carcinosarcoma (UCS); Glioblastoma (GBM); Renal chromophobe renal cell carcinoma (KICH); Thyroid cancer (THCA); Low-grade glioma (LGG); Lung adenocarcinoma (LUAD); Mesothelioma (MESO);Pheochromocytoma and paraganglioma (PCPG); Testicular cancer (TGCT); Ocular melanomas (UVM); Thymoma (THYM); Biliary tract cancer (CHOL); Esophageal cancer (ESCA); and Stomach cancer (STAD).

[0216] A comparative bioinformatic analysis of the expression of the gene encoding PMEL17 against clinically approved targets and / or clinical under-assessment for the ADC approach (CD20, CD30, CD33, CD38, BCMA and GPCR20) was performed from the TCGA database in the following indications: in leukemias, lymphomas and multiple myeloma.

[0217] RESULTS

[0218] The measured PMEL17 gene expression levels are low in healthy tissues compared to the different clinically approved targets for the ADC approach (HER-2, TROP-2, and NECTIN-4) (Figures 1-4). Indeed, the PMEL17 gene expression level is less than 5 in all healthy tissues except keratinocytes (Figure 1).

[0219] The measured PMEL17 gene expression levels are comparable to the NECTIN-4 target in the different indications (Figures 5-7). However, they are significantly higher than the various targets (HER-2, TROP-2, and NECTIN-4) in melanoma biopsies from patients in the TCGA database (Figures 5-7) and in xenograft biopsies from patients in the LIDE platform (Figure 9). PMEL17 gene expression levels were also found in hematological malignancies, with levels close to BCMA in acute myeloid leukemia, higher than CD30 in multiple myeloma, and higher than GRP20 in DLBCL lymphoma (Figure 8) in biopsies from patients in the GEO database for multiple myeloma and the TCGA database for leukemias and DLBCL.

[0220] Finally, the very good ratio of healthy tissue / tumor tissue transcriptomic expression measured highlighted that PMEL17 is a preferred target for the ADC approach in several indications, including the different types of melanomas.

[0221] EXAMPLE No. 2 - Anti-PMEL17 Antibody

[0222] MATERIALS & METHODS

[0223] Antibody production

[0224] The SKM300 antibody was produced using the CHO cell line. Molecular weight

[0225] The molecular weight of the SKM300 antibody was measured by SDS-PAGE under reducing and non-reducing conditions.

[0226] Purity

[0227] The purity of the SKM300 antibody was measured by SDS-PAGE under reducing and non-reducing conditions and by size exclusion chromatography (SEC-HPLC) in high-performance liquid chromatography.

[0228] RESULTS

[0229] 16.73 mg of the SKM300 antibody in human lgG1 L234A L235A format was produced at a final concentration of 2.39 mg / mL in sterile PBS at pH 7.2–7.4. The measured molecular weight was as expected: 49 kDa for the heavy chain and 24 kDa for the light chain under reducing conditions, and 146 kDa for the antibody under non-reducing conditions (Figure 10). The purity of the SKM300 antibody was greater than 95% by SDS-PAGE (Figure 10) and was measured at 99.649% by SEC-HPLC (Figure 11).

[0230] EXAMPLE No. 3 - Production of ADCs

[0231] MATERIALS & METHODS

[0232] Linkers-droues

[0233] The Linkers-drugs used are:

[0234] ■ Mal-Glu-(Phe-Lys-PAB-exatecan)-PEGw of formula (X) Mal-Glu-(Val-Ala-PAB-exatecan)-PEGw of formula (XI) (XI).

[0235] Antibody

[0236] The anti-PMEL17 antibodies used are:

[0237] ■ SKM300 without LALA mutation (SEQ ID NOs: 9 and 13); and

[0238] ■ the SKM300 with LALA mutation (SEQ ID NOs: 9 and 15).

[0239] Conjugation protocol

[0240] This involves 3 steps.

[0241] In the first step of the reduction, the reducing agent TCEP (tris(2-carboxyethyl)phosphine) was tested at 9 molar equivalents. In this first step, the reduction reaction lasted 16 hours, the temperature was 22°C, and the concentration was 2.0 mg / mL.

[0242] In the second conjugation step, 16.0 molar equivalents of the Mal-Glu-(Phe-Lys-PAB-Exatecan)-PEGw or Mal-Glu-(Val-Ala-PAB-Exatecan)-PEGw reagent were used with the antibody. In this second step, the conjugation reaction time was 1 h, the temperature was 22°C, and 10% DMSO was used as a co-solvent.

[0243] In the third purification step, ultrafiltration by centrifugation (Amicon 30K) was used. The ADC was collected in the final buffer: PBS 20 mM Histidine, 8% sucrose (w / v), pH 5.5.

[0244] The ADC SKM300 (with LALA mutation) was produced in larger quantities using the same protocol.

[0245] Characterization of ADCs

[0246] The reactions were analyzed by size exclusion chromatography (SEC-H PLC) using high-performance liquid chromatography. The drug-antibody ratio (DAR) of the ADC was determined by liquid chromatography coupled with mass spectrometry and ultraviolet spectrophotometry at a wavelength of 280 nm (UV / LC-MS). RESULTS

[0247] Size exclusion chromatography (SEC-HPLC) analysis determined that the produced ADCs had high monomeric purity (greater than 99%) (Figure 12). UV / LC-MS analysis accurately determined that the DAR is equal to 7.99 (Figure 13).

[0248] Finally, the conjugation protocol implemented made it possible to produce the ADC of the invention, which was characterized as follows:

[0249] Table 2. Summary of the characteristics of the ADCs produced

[0250] EXAMPLE No. 4 - Studies of PMEL17 expression in melanoma cell lines

[0251] MATERIALS & METHODS

[0252] Cell lines

[0253] The following lines were used: SK-MEL-5 (ATCC-HTB-70, EMEM + 10% FBS), SK-MEL-3 (ATCC-HTB-69 McCoy's 5a+15% FBS), SK-MEL-28 (ATCC-HTB-72, EMEM + 10% FBS), MEWO (ATCC-HTB-65, EMEM + 10% FBS) and IGR-37 (DSMZ-ACC-237, DMEM+ 15% FBS).

[0254] Marking

[0255] The adherent cells were detached using 2.5 mM EDTA and suspended. They were then collected in 100 L of PBS per tube (3.10 5 cells) on ice. For each cell type, the cells were prepared in two identical samples, one for labeling with the anti-PMEL17 antibody and the other for labeling with the control isotype.

[0256] [1] In the first tube, the cells were incubated respectively with a cell viability marker (L / D BV421) in addition to the human anti-PMEL17 antibody and in a second time with a secondary anti-human IgG Fc PE antibody.

[0257] [2] In the second tube, the cells were incubated with a cell viability marker (L / D BV421) in addition to the human control isotype lgG1 kappa and subsequently with the anti-human secondary antibody IgG Fc PE.

[0258] To achieve this, the following steps were taken:

[0259] 5 pL of human Fc blocking solution and 0.15 pL of the Live / Dead marker dilution (L / D BV421) were added. After homogenization, the cell suspension was incubated at 4°C in the dark for 10 min. 1.5 pg of human anti-PMEL17 antibody were added to tube 1 and 1.5 pg of the human lgG1 kappa control isotype were added to tube 2. After homogenization, the cell suspensions were incubated at 4°C in the dark for 1 h. After two DPBS washes, the cells were diluted with 500 pL of DPBS. Then, 5 pL of the anti-human IgG Fc-PE secondary antibody were added to each tube and incubated at 4°C for 45 min in the dark. After two washes with DPBS, the cells were re-suspended in 300 pL of DPBS and stored at 4°C for reading by FACS.

[0260] RESULTS

[0261] Protein expression measured by FACS showed that all melanoma cell lines used express PMEL17. In particular, a fluorescence intensity (MFI) ranging from 300 to 2500 was measured (Figure 14).

[0262] Finally, these results confirmed previous data on the transcriptomic expression of PMEL17 and the interest of this therapeutic target.

[0263] EXAMPLE No. 5 - Studies of the efficacy of the anti-PMEL17 ADC in melanoma cell lines in vitro

[0264] MATERIALS & METHODS

[0265] Cell lines

[0266] The following lines were used: SK-MEL-5 (ATCC-HTB-70, EMEM + 10% FBS), SK-MEL-28 (ATCC-HTB-72, EMEM + 10% FBS), and IGR-37 (DSMZ-ACC-237, DMEM + 15% FBS). Compounds tested

[0267] ADCs:

[0268] ■ anti-ETB-R = SKM1O4-[Mal-Glu-(Phe-Lys-PAB-Exatécan)-PEGio] (abbreviated SKM104-MA-L2 - FR Application No. 23 / 13069);

[0269] ■ anti-PMEL17 = SKM3OO-[Mal-Glu-(Phe-Lys-PAB-Exatécan)-PEGio] (abbreviated SKM300-MA-L2).

[0270] Evaluation of cytotoxicity in vitro

[0271] To determine the effect of ADC on cell viability, cells were seeded at 1200 for SK-MEL-28 and 1500 for the other cells in 100 pL of complete culture medium in a 96-well flat-bottom plate. After overnight incubation at 37°C, 100 pL of medium containing a serial dilution of each compound with a maximum concentration of 45 pg / mL was added as a duplicate. After 6 days of incubation, cell survival was determined by the addition of 20 pL of CelITiter 96® AQueous One Solution Reagent (G3581, Promega). After 2 hours of incubation at 37°C, absorbance was determined at 490 nm (Multiskan, Thermo Fisher). The cell viability ratio (%) was calculated using the following formula:

[0272] 17- ur Viability (

[0273] The 50% inhibitory concentration (IC50) was calculated using GraphPad Prism® version 10 software.

[0274] RESULTS

[0275] A dose-dependent decrease in the cell viability of SK-MEL-5, SK-MEL-28, and IGR-37 was observed. At the evaluated doses, the ADC SKM300-MA-L2 induced an unexpected and significantly greater decrease in cell proliferation than that of the ADC SKM104-MA-L2. The calculated ICso of SKM300-MA-L2 is on the order of 1 nM in the different cell lines (Figure 15, Table 3).

[0276] Table 3. Measurement of ICso. Finally, these results demonstrated the impressive efficacy of SKM300-MA-L2 on aggressive cutaneous melanoma cell lines resistant to numerous chemotherapies. In doing so, these data demonstrated the efficacy of the ADCs of the invention.

[0277] EXAMPLE #6 - Comparative evaluation of the efficacy of various anti-PMEL17 ADCs in models resistant to DXd and MMAE topoisomerase inhibitors

[0278] Materials and Methods

[0279] Resistant cell lines used

[0280] Triple-Negative Breast Cancer (TNBC): HCC1806-DxdR, HCC1954-DxdR

[0281] Non-Small Cell Lung Cancer (NSCLC): HCC827-DxdR, HCC4006-DxdR

[0282] Dual-resistant model (DXd + MMAE): MC38-hu-PMEL-R

[0283] Tested compounds - Anti-PMEL17 ADCs (SKM300 series)

[0284] Internal Name - Structure, Abbreviation

[0285] SKM3OO-[Mal-Glu-(Phe-Lys-PAB-Exatecan)-PEGio], SKM300-MA-L2

[0286] SKM300-[Mal-Glu-PEGw-Phe-Lys-PAB-Exatecan), SKM300-MA-L3

[0287] SKM3OO-[Mal-Glu-(Val-Ala-PAB-Exatecan)-PEGio], SKM300-MA-L1 SKM300-[Mal-Glu-(Phe-Lys-PAB-Topotecan)-PEGio], SKM300-MA-L5 SKM300-[Mal-Glu-(Phe-Lys-PAB-Camptothecin)-PEGio], SKM300-MA-L6 SKM300-[Mal-Glu-(Phe-Lys-PAB-PROTAC)-PEGio], SKM300-MA-L7 SKM3OO-[Mal-Glu-(Val-Ala-PAB-Exatecan)-PSARio], SKM300-MABLINK

[0288] SKM300-[TMALIN Platform], ADC developed according to the TMALIN architecture, SKM300-MA-L8 SKM300-[PROFOUDBIO Platform], ADC developed according to PROFOUDBIO, SKM300-MA-L9

[0289] Anti-PMEL17-vc-MMAE

[0290] Experimental protocol

[0291] Cells are seeded in 96-well flat-bottom plates at a density of 1500 cells / well in 100 pL of complete medium. After 24 h incubation at 37°C, 100 pL of medium containing serial dilutions of the ADCs (maximum concentration: 45 pg / mL) are added. Each condition is tested in duplicate.

[0292] After 6 days, cell viability is measured by the CelITiter 96® AQueous One Solution Reagent test (Promega G3581), reading at 490 nm.

[0293] Viability (%) is calculated according to the formula: 17- U r Viability (

[0294] The IC50s are calculated via GraphPad Prism® v10.

[0295] RESULTS

[0296] In the HCC1806-DxdR, HCC1954-DxdR, HCC827-DxdR, HCC4006-DxdR, and MC38-hu-PMEL-R cell lines, the ADC SKM300-MA-L2 induces the best cytotoxicity. Conversely, the ADC PMEL17-vc-MMAE has no effect on these chemoresistant models.

[0297] EXAMPLE #7 - Induction of ATP release (ICD marker) by SKM300-MA-L2

[0298] Materials & Methods

[0299] Lines used

[0300] • HCC1806-DxdR (TNBC, DXd resistant)

[0301] . HCC827-DxdR (NSCLC, DXd resistant)

[0302] Tested compounds

[0303] • SKM300-MA-L2 (anti-PMEL17-[Mal-Glu-(Phe-Lys-PAB-Exatecan)-PEGio])

[0304] • Enhertu (Trastuzumab-DXd, Exatecan payload, DAR ~8)

[0305] Anti-PMEL17-vc-MMAE

[0306] Experimental conditions

[0307] • Concentrations tested: 1 pg / mL and 3.3 pg / mL

[0308] • Treatment duration: 24h, 72h, 96h

[0309] • ATP detection kit: ENLITEN® ATP Assay System Bioluminescence Detection Kit for ATP Measurement (Promega)

[0310] Protocol

[0311] 1. Resistant cells are cultured under standard conditions (RPMI + 10% FBS, 37°C, 5% CO2).

[0312] 2. The cells are treated with the aforementioned ADCs at two concentrations, in triplicate, in 96-well plates.

[0313] 3. Extracellular ATP is measured by luminescence at each time point using the ENLITEN® kit, according to the manufacturer's instructions. 4. Luminescence intensity is reported in relative units (RLU) after subtracting the background.

[0314] RESULTS At all time points (24h, 72h, 96h), the ADC SKM300-MA-L2 induced the greatest increase in ATP release (>2* background). Neither Enhertu nor the anti-PMEL17-vc-MMAE produced a comparable release. The effect was reproducible in both resistant cell lines (HCC 1806-DxdR and HCC827-DxdR).

Claims

DEMANDS 1. Antibody-drug conjugate (ADC) of formula (I): (I), in which: ■ Ac is an anti-PMEL17 antibody, one of its fragments or one of its derivatives; ■ TC is a conjugation head chosen from: maleimide coupled to glutamic acid (Mal-Glu), polyether, amino acids, benzyl group, amines and ketones; ■ B represents "PEG2-Glu-(Glu-Met)" and is either absent or present; ■ L is a linker cleavable by lysosomal cathepsins, said cleavable linker possibly being coupled to p-aminobenzyl alcohol (PAB) or one of its derivatives; ■ M is a drug chosen from: topoisomerase inhibitors, alkylating agents, antimicrotubule agents and their prodrug forms; and ■ AS is a solubilizing agent selected from: polysarcosine (PSAR) and polyethylene glycol (PEG), and in which the drug-antibody ratio (DAR) is between 2 and 16 and said anti-PMEL17 comprises: ■ a lightweight chain comprising from the N-terminal end to the C-terminal end: - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1); - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and ■ a heavy chain comprising from the N-terminal end to the C-terminal end: - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4); - CDR2, whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

2. Antibody-drug conjugate according to claim 1, wherein said anti-PMEL17 comprises: ■ a light chain comprising a variable region having at least 80% identity with the sequence SEQ ID NO: 7, said variable region comprising from the N-terminal end to the C-terminal end: - the CDR1 whose amino acid sequence includes or consists of RATKSISKYLA (SEQ ID NO: 1); - CDR2, whose amino acid sequence includes or consists of SGSTLQS (SEQ ID NO: 2); and - CDR3, whose amino acid sequence includes or consists of QQHNEYPYT (SEQ ID NO: 3), and ■ a heavy chain comprising a variable region having at least 80% identity with the sequence SEQ ID NO: 11, said variable region comprising from the N-terminal end to the C-terminal end: - CDR1 whose amino acid sequence includes or consists of GYSFTRYTMN (SEQ ID NO: 4); - CDR2, whose amino acid sequence includes or consists of VINPYNGGTVYNQKFKG (SEQ ID NO: 5); and - CDR3 whose amino acid sequence includes or consists of TDYDGYAMDY (SEQ ID NO: 6).

3. Antibody-drug conjugate according to claim 1, wherein said anti-PMEL17 comprises a light chain comprising from the N-terminal end to the C-terminal end: ■ a light chain having at least 80% identity with sequence SEQ ID NO: 9, said light chain comprising a variable region of sequence SEQ ID NO: 7, and a heavy chain having at least 80% identity with the sequence SEQ ID NO: 13, said heavy chain comprising a variable region of sequence SEQ ID NO: 11 and comprising in particular a LALA mutation.

4. Antibody-drug conjugate according to any one of claims 1 to 3 for its use as a medicinal product.

5. Antibody-drug conjugate according to any one of claims 1 to 3 for its use in the prevention and / or treatment of a tumor.

6. Pharmaceutical composition comprising the antibody-drug conjugate according to any one of claims 1 to 3 and a pharmaceutically acceptable vehicle.

7. Pharmaceutical composition according to claim 6 wherein said antibody-drug conjugate is at a dose of 1 to 1000 mg.

8. Pharmaceutical composition according to claim 6 or 7 for its use in the prevention and / or treatment of a tumor.

9. Pharmaceutical composition for its use according to claim 8, said pharmaceutical composition being in a form suitable for administration by one of the following routes: parenteral, injectable, intratumoral, topical, inhalation, subcutaneous, nasal, intratumoral or pulmonary.

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