Novel radiolabelled antibodies

Abstract

The invention relates to radiolabelled girentuximab antibodies and humanised versions conjugated to a radionuclide Astatine211. The antibody conjugates are used in radiotherapy in treating urothelial cancer, including bladder cancer.

Description

Novel radiolabelled antibodiesField of the invention

[0001] The invention relates to radiolabelled molecules, preferably antibodies, for the treatment of urothelial cancer, and methods of use thereof.Related application

[0002] This application claims priority from Australian provisional applicationAU 2023903890, the entire contents of which are hereby incorporated by reference.Background of the invention

[0003] Molecular targeted radiotherapy (MTR) is an emerging approach for the treatment of cancers and includes the use of radiolabelled agents for binding to a molecular target.

[0004] However, the mere presence of a molecular target on a tumour is not always indicative that the cancer can be usefully treated using molecular targeted radiotherapy.

[0005] Accordingly, there is a need for new agents and methods for treating cancers for which there is currently an unmet need, or that have previously not been successfully targeted using MTR.

[0006] Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and / or combined with other pieces of prior art by a skilled person in the art.Summary of the invention

[0007] The present invention relates to molecules and methods for treating urothelial cancer, particularly urothelial cancer that expresses the antigen carbonic anhydrase IX (CAIX).

[0008] The present invention therefore provides a radiolabelled girentuximab antibody, or antigen binding fragment thereof, wherein the antibody or antigen binding fragment is conjugated to the radioisotope 211 -Astatine.

[0009] As used herein, such a radiolabelled antibody may be referred to as211At- girentuximab or 21 1 -At-GmAb.

[0010] In any aspect or embodiment, the radioisotope may be conjugated to the girentuximab directly e.g. by halogenation of amino acid residues.

[0011] Preferably, the radioisotope is linked indirectly to the girentuximab or antigen binding fragment thereof, for example via a prosthetic group. The girentuximab or antigen binding fragment thereof may be conjugated to a bifunctional linker, for example, bromoacetyl, thiols, succinimide ester, TFP ester, a maleimide, aryliodonium salts or using any amine or thiol-modifying chemistry known in the art; and the radioisotope conjugated to the bifunctional linker.

[0012] In alternative examples, the bifunctional linker (prosthetic group) may be first radiolabelled, and the radiolabelled prosthetic group then conjugated to the girentuximab or antigen binding fragment thereof.

[0013] Examples of methods for astatination of prosthetic groups (such as diaryliodonium salts) are known in the art, for example in WO2019027059 and WO20 17 / 089492, incorporated herein in their entirety by cross-reference.

[0014] Optionally, the radioisotope may be linked indirectly to the girentuximab or antigen binding fragment thereof, via a chelator. In one example, the girentuximab is conjugated to a chelating moiety, selected from the group consisting of: TMT (6,6"- bis[N,N",N"'-tetra(carboxymethyl)aminomethyl)-4'-(3-amino-4-methoxyphenyl)-2,2':6',2"- terpyridine), DOTA (1 , 4,7,10-tetraazacyclododecane-NN',N"(N"'-tetraacetic acid), TCMC, DO3A, CB-DO2A, NOTA, Diamsar, DTPA, CHX-A”-DTPA, TETE, Te2A, HBED, DFO, DFOsq, DFO-NCS and HOPO, a chelator as described in WO 2022 / 133537 (incorporated herein by cross-reference) or other chelating agent as described herein or known to the skilled person - to provide a girentuximab bioconjugate. The radioisotope may then be conjugated to the chelating moiety of the conjugate.

[0015] The terms “chelate” or “chelator” as used herein, refer to an organic compound or portion thereof that can be bonded to a central metal or radiometal atom at two or more points.

[0016] The terms “conjugate” or “bioconjugate” as used herein, refer to a molecule that contains a chelating group or metal complex thereof, a linker group, and which optionally contains a therapeutic moiety, targeting moiety, or cross-linking group.

[0017] In a further aspect there is provided a method for obtaining a radiolabelled girentuximab of the invention, wherein the method comprises astatination of a prosthetic group which is then conjugated to the girentuximab. In any embodiment, the astatination of a prosthetic group comprises a method as described in WO2019 / 027059 or WO20 17 / 089492, incorporated herein by reference.

[0018] In alternative embodiments, the method comprises directly radiolabelling girentuximab with the radioisotope 211 -At. Alternatively, the method comprises radiolabelling a girentuximab bioconjugate with the radioisotope 21 1 -At. Optionally, the girentuximab bioconjugate comprises a girentuximab antibody conjugated to a prosthetic group (such as described in WO2019 / 027059 or WO2017 / 089492) or any chelating or linker group suitable for further conjugation to a radioisotope.

[0019] In a further aspect, there is provided a pharmaceutical composition comprising an 211 -At-girentuximab antibody, or antigen binding fragment thereof, as herein described, optionally in combination with a pharmaceutically acceptable excipient.

[0020] The invention also provides a method of treating, preventing or minimising progression of urothelial cancer in a subject, the method comprising:- administering to a subject in need thereof, a 21 1 -At-girentuximab antibody or antigen binding fragment thereof, thereby treating, preventing or minimising progression of the urothelial cancer in the subject.

[0021] In a further aspect, the present invention provides a method of minimising, reducing or preventing growth of a urothelial cancer tumour in a subject, the method comprising:- administering to a subject in need thereof, 211 -At-girentuximab antibody or antigen binding fragment thereof, thereby minimising, reducing or preventing growth of urothelial cancer in the subject.

[0022] In a further aspect, the present invention provides a method of minimising, reducing or preventing metastasis of urothelial cancer in a subject, the method comprising:- administering to a subject in need thereof, 211 -At-girentuximab antibody or antigen binding fragment thereof, thereby minimising, reducing or preventing metastasis of urothelial cancer in the subject.

[0023] In a further aspect, the present invention provides a method of increasing survival of a subject suffering from urothelial cancer, the method comprising:- administering to a subject in need thereof, a 211 -At-girentuximab antibody or antigen binding fragment thereof, thereby increasing survival of the subject.

[0024] In another aspect, the present invention provides use of a 211 -At-girentuximab antibody or antigen binding fragment thereof in the manufacture of a medicament for:- treating, preventing or minimising progression of urothelial cancer in a subject,- minimising, reducing or preventing growth of a urothelial cancer tumour in a subject,- minimising, reducing or preventing metastasis of a urothelial cancer in a subject, or- increasing survival of a subject suffering from urothelial cancer.

[0025] In another aspect, the present invention provides use of a girentuximab antibody bioconjugate for conjugation to 211 -At, in the manufacture of a medicament for:- treating, preventing or minimising progression of urothelial cancer in a subject,- minimising, reducing or preventing growth of a urothelial cancer tumour in a subject,- minimising, reducing or preventing metastasis of a urothelial cancer in a subject, or- increasing survival of a subject suffering from urothelial cancer.

[0026] In another aspect, the present invention provides use of a 211 -At-girentuximab antibody or antigen binding fragment thereof for:- treating, preventing or minimising progression of urothelial cancer in a subject,- minimising, reducing or preventing growth of a urothelial cancer tumour in a subject,- minimising, reducing or preventing metastasis of urothelial cancer in a subject, or- increasing survival of a subject suffering from urothelial cancer.

[0027] In another aspect, the present invention provides a 211 -At-girentuximab antibody or antigen binding fragment thereof for use in:- treating, preventing or minimising progression of urothelial cancer in a subject,- minimising, reducing or preventing growth of a urothelial cancer tumour in a subject,- minimising, reducing or preventing metastasis of urothelial cancer in a subject, or- increasing survival of a subject suffering from urothelial cancer.

[0028] In any method or use described herein, the urothelial cancer may be selected from bladder cancer, urethral cancer, ureteral cancer or renal pelvic cancer. Preferably the cancer is bladder cancer. Optionally the subject may have bladder cancer and may be a candidate for radical cystectomy.

[0029] In any aspect or embodiment of the invention, it will be understood that the amount of 211 -At-girentuximab antibody or antigen binding fragment thereofadministered to a subject, is a therapeutically effective amount of 21 1 -At-girentuximab antibody or antigen binding fragment thereof.

[0030] In any aspect of the invention, any medicament or pharmaceutical composition described herein may be suitable for administration intraperitoneally, intratumourally, topically, orally, intravenously, to the respiratory tract, preferably by inhalation or intranasally, subcutaneously, intramuscularly intracavitarily or intravesically. Typically, any medicament or pharmaceutical composition described herein is suitable for administration intravenously.

[0031] In any method or use described herein, the 21 1 -At-girentuximab antibody or antigen binding fragment thereof may be administered as the sole treatment for urothelial cancer or may be administered in combination with one or more additional treatments. The 21 1 -At-girentuximab antibody or antigen binding fragment thereof may be administered subsequent to a previous treatment for urothelial cancer (optionally wherein the previous treatment comprises radiosensitising treatment, surgery, chemotherapy, immunotherapy (such as Bacillus Calmette-Guerin (BCG)), external beam radiation, autologous stem cell therapy, or combinations thereof). The 21 1 -At-girentuximab antibody or antigen binding fragment thereof may be administered concomitantly with or sequentially with an additional treatment for cancer (optionally wherein the additional treatment comprises surgery, chemotherapy, immunotherapy, external beam radiation, autologous stem cell therapy, or combinations thereof).

[0032] In any method or use described herein, the subject requiring treatment may have received a previous treatment for urothelial cancer (such as surgery, chemotherapy, immunotherapy (such as Bacillus Calmette-Guerin (BCG)), external beam radiation, autologous stem cell therapy, or combinations thereof), but was not responsive to that prior treatment. In a particularly preferred embodiment, the subject requiring treatment may have received a prior treatment with BCG but was deemed unresponsive to that treatment (in other words, the subject is a “non-responder to BCG” treatment).

[0033] In still further embodiments, the subject requiring treatment may be deemed to be unlikely to respond to BCG treatment (eg as a result of prior screening or diagnostic method).

[0034] It will be understood that preferably in accordance with the above mentioned aspects and embodiments, that the urothelial cancer is preferably one that expresses or overexpresses carbonic anhydrase IX (CAIX).

[0035] In any embodiment, the urothelial cancer may be non-metastatic. In any embodiment, the urothelial cancer may be malignant or metastatic.

[0036] In any embodiment, the methods further comprise identifying a subject in need of treatment as described herein. The method may comprise identifying that the subject has a urothelial cancer expressing or overexpressing CAIX.

[0037] In any embodiment or aspect, the girentuximab antibody or antigen binding fragment thereof comprises:(a) a heavy chain variable domain (VH) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 84, 100, 116, 132, 148 or 164.

[0038] In any embodiment, the antibody or antigen binding fragment thereof comprises an antigen binding domain that binds specifically to carbonic anhydrase IX (CAIX) and comprises:FR1 - CDR1 - FR2 - CDR2 - FR3 - CDR3 - FR4 - linker - FR1 a - CDR1 a - FR2a - CDR2a - FR3a - CDR3a - FR4a wherein:FR1 , FR2, FR3 and FR4 are each framework regions;CDR1 , CDR2 and CDR3 are each complementarity determining regions;FR1 a, FR2a, FR3a and FR4a are each framework regions;CDR1 a, CDR2a and CDR3a are each complementarity determining regions;wherein the sequence of any of the complementarity determining regions have an amino acid sequence as described in Table 1 below. Preferably, the framework regions have an amino acid sequence also as described in Table 1 below, including amino acid variation at particular residues which can be determined by aligning the various framework regions derived from each antibody. The CDR1 , CDR2 and CDR3 may be sequences from the VH, CDR1 a, CDR2a and CDR3a may be sequences from VL, or the CDR1 , CDR2 and CDR3 may be sequences from the VL, CDR1 a, CDR2a and CDR3a may be sequences from VH.

[0039] In any embodiment, the antigen or antigen binding fragment thereof comprises:(i) a VH comprising a complementarity determining region (CDR) 1 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence at least about 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% or at least 99% identical to a sequence set in SEQ ID NO: 2, and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 3;(ii) a VH comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(iii) a VL comprising a CDR1 comprising a sequence at least about 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% or at least 99% identical to asequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 82 and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 83;(iv) a VL comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 84, 100, 1 16, 132, 148 or 164;(v) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth in SEQ ID NO: 2 and a CDR3 comprising a sequence set forth in SEQ ID NO: 3;(vi) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(vii) a VL comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83;(viii) a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164;(ix) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth between in SEQ ID NO: 2, and a CDR3 comprising a sequence set forth in SEQ ID NO: 3; and a VL comprising a CDR1 comprising a sequence set SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83; or(x) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68 and a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164.

[0040] In a further embodiment, the antibody or antigen binding fragment thereof comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 1 1 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 12, 28, 44, 60 or 76; and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence at least about 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 least93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% at least 99% identical to a sequence as set forth in any of SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 92, 108, 124, 140, 156 or 172.

[0041] In a further embodiment, the antibody or antigen binding fragment thereof comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consisting of a sequence as set forth in SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 11 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 12, 28, 44, 60 or 76, and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence as set forth in SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 92, 108, 124, 140, 156 or 172.

[0042] In any embodiment, the antibody or antigen binding fragment thereof that specifically binds to CAIX comprises an amino acid sequence that consists essentially of or consists of (in order of N to C terminus or C to N terminus) any one of SEQ ID NO: 4, 20, 36, 52 or 68 and / or any one of SEQ ID NO: 84, 100, 1 16, 132, 148, 164.

[0043] In any embodiment, the antibody or antigen binding fragment thereof comprises:(a) a heavy chain variable domain (VH) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID NOs: 84, 100, 1 16, 132, 148 or 164.

[0044] As described herein, the girentuximab antibody or antigen binding fragment thereof may be in the form of:(i) a single domain antibody (sdAb);(ii) a single chain Fv fragment (scFv);(iii) a dimeric scFv (di-scFv); or(iv) one of (ii) or (iii) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.

[0045] Further, as described herein, the girentuximab or antigen binding fragment thereof may be in the form of:(i) a minibody (eg scFv-CH3)(ii) a diabody;(iii) a triabody;(iv) a tetrabody;(v) a Fab;(vi) a F(ab’)2;(vii) a Fv;(vii i) a bispecific antibody or other form of multispecific antibody; or(ix) one of (i) to (viii) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.

[0046] Optionally, the variable heavy and variable light regions of the antigen binding domain are joined via a linker.

[0047] In any embodiment, the antigen binding domain may comprise:FR1 - CDR1 - FR2 - CDR2 - FR3 - CDR3 - FR4 - linker - FR1 a - CDR1 a - FR2a - CDR2a - FR3a - CDR3a - FR4a.

[0048] As defined herein, the linker may be a chemical, one or more amino acids, or a disulphide bond formed between two cysteine residues.

[0049] Preferably, the girentuximab is in the form of a full IgG antibody.

[0050] In any aspect or embodiment of the present invention, the girentuximab or antigen binding fragment thereof may comprise a human constant region, e.g., an IgG constant region, such as an IgGi, lgG2, IgGa or lgG4 constant region or mixtures thereof. In the case of an antibody or protein comprising a VH and a Vi_, the VH can be linked to a heavy chain constant region and the VL can be linked to a light chain constant region.

[0051] In one example, the girentuximab or antigen binding fragment thereof comprises a constant region of an lgG4 antibody or a stabilised constant region of an lgG4 antibody. In one example, the girentuximab or antigen binding fragment thereof comprises an lgG4 constant region with a proline at position 241 (according to the numbering system of Kabat (Kabat et al., Sequences of Proteins of Immunological Interest Washington DC United States Department of Health and Human Services, 1987 and / or 1991 )).

[0052] In one example, the girentuximab or antigen binding fragment thereof comprises a heavy chain constant region, comprising a stabilised heavy chain constant region, comprising a mixture of sequences fully or partially with or without the C-terminal lysine residue.

[0053] In further embodiments of any aspect herein, the girentuximab or antigen binding fragment thereof comprises an Fc region wherein the Fc region is engineered to have enhanced capacity to induce antibody-dependent cell-mediated cytotoxicity (ADCC). Preferably, the enhanced capacity to induce ADCC is conferred by mutation, deletion or modification of amino acids in the Fc region which interact with an Fc receptor

[0054] In another embodiment, the girentuximab or antigen binding fragment thereof comprises an Fc region that is engineered to:- have increased in vitro or in vivo half-life;- have an increased capacity to induce antibody-dependent cell mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) or complement-dependent cytotoxicity; and / or- have reduced effector function.

[0055] Preferably, the girentuximab antibody is in the form of an antibody (ie comprising a variable light and variable heavy chain, linked to a constant region of an antibody including a heavy chain CH2 and / or CH3).

[0056] In further embodiments, the girentuximab may comprise a heavy chain constant region as defined in SEQ ID NO: 177, 178, 179 or 180 and / or a light chain constant region as defined in SEQ ID NO: 181 .

[0057] In certain embodiments, the girentuximab may comprise a heavy chain as set forth in any of SEQ ID NO: 182, 183, 184, or 185 and / or a light chain as set forth in SEQ ID NO: 186.

[0058] In still further embodiments, the girentuximab is in the form of an antibody and may comprise one or more amino acid substitutions in the constant regions, so as to reduce the in vivo half-life of the antibody. The present invention therefore provides for an girentuximab antibody having substitutions in the CH2 and / or CH3 domains of the constant region and comprising substitutions at one or more of residues His310, His435, Tyr436 and Ile253 (Kabat numbering), thereby altering FcRn binding affinity and / or serum half-life of said antibody (eg relative to an girentuximab that comprises a native CH2 and CH3 domain).

[0059] In some examples, the amino acid at position 310 and / or 435 of the antibody may be alanine, glutamic acid, aspartic acid, leucine, isoleucine, arginine, proline, glutamine, methionine, serine, threonine, lysine, asparagine, phenylalanine, tyrosine, tryptophan, cysteine, valine or glycine.

[0060] Preferably, the residue at position 310 is selected from alanine, or glutamic acid or glutamine; or amino acid residue 435 from the heavy chain constant region is selected from arginine, glutamine or alanine. In other preferred embodiments, the antibody has an alanine residue at position 310 and glutamine residue at position 435.

[0061] In a further embodiment, the antibody also comprises an amino acid substitution at residue Lys322. Preferably the substitution is K322A.

[0062] In particularly preferred embodiments, the girentuximab antibody comprises substitutions K322A, H310A and H435Q.

[0063] In a preferred embodiment, the binding affinity for FcRn and / or the serum half-life of the modified antibody is decreased by at least about 2-fold, 3-fold, 4-fold, 5-fold, 10- fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, or 100-fold. In a preferred embodiment of the present invention, the binding affinity for FcRn and / or the serum half-life of said modified antibody is reduced by at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97%, 98%, or 99%.

[0064] In any aspect or embodiment, the antibody may also comprise amino acid substitutions at residues equivalent to Ser228 and Leu235 of the constant heavy chain region, such as Ser228Pro and / or Leu235Glu.

[0065] As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps.

[0066] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.Brief description of the drawings

[0067] Figure 1 : Survival of RT112 cells following exposure to177Lu-girentuxumab (177Lu-GmAb) or to211At-girentuximab (211At-GmAb).

[0068] Figure 2: %ID / g after intravesical instillation of211At-girentuximab in mice at 30 min, 1 hour and 4 hour (left to right).

[0069] Figure 3: %ID / organ after intravesical instillation of211At-girentuximab in mice at 30 min, 1 hour and 4 hour (left to right).

[0070] Figure 4: Schematic of assay schedule for internalisation study.

[0071] Figure 5: Kinetics of internalization of125l-girentuximab in RT112 cells.

[0072] Figure 6: Assessment of the uptake and wash-out kinetics of125l-girentuximab in RT1 12 cells after the washing step at 2 hours.Detailed description of the embodiments

[0073] The present invention relates to the treatment of urothelial cancers (such as bladder cancer, urethral, ureteral, rectal, renal pelvis and other cancers), for which there is currently a lack of robust oncology management options. To improve the morbidity and mortality of this indication, therapeutic innovation is needed.

[0074] Current approaches to the treatment of urothelial cancer typically include surgery, which may also require subsequent chemotherapy and / or radiotherapy to prevent recurrence. In the case of bladder cancer, radical cystectomy may also be required if the tumour cannot easily be removed but this is a significant surgical intervention that can have a profound impact on a patient’s quality of life. For example in men, radical cystectomy surgery typically also involves removal of the prostate and seminal vesicles. For women, radical cystectomy surgery may also involve removal of the ovaries, uterus and part of the vagina.

[0075] The use of radiolabelled CAIX-binding antibody is known in the context of treatment of renal cell carcinomas. However, prior to the present invention, it was not known whether the molecular targeting of CAIX could be used to successfully treat other solid cancers which may express CAIX.

[0076] Although CAIX is typically associated with advanced disease, it is not known whether molecular targeting of CAIX for radioimmunotherapy is possible during the early stages of certain cancers, or if the cancer can only be targeted in late disease. Further, some cancer exhibit reduced expression as disease progresses and it is therefore also not clear whether CAIX targeting is a useful means for treating these types of cancers.

[0077] Moreover, given the heterogeneity of many cancers, the simple presence of expression of CAIX (eg as determined by immunohistochemistry techniques), does not necessarily indicate that the cancer could be treated using molecular targeting radioimmunotherapeutic methods. For example, in a recent study published by Huizing et al (2021 , Physics and Imaging in Radiation Oncology, 145-150), it was found that a111In-labelled F(ab’)2 form of the CAIX-binding antibody girentuximab, was not able to discriminate between tumour and non-tumour cells and it was therefore concluded that this agent would not be useful for imaging of head and neck cancers. In contrast, the present inventors have demonstrated that radiolabelled girentuximab is useful for the treatment of the same cancer cell type; demonstrating that the outcomes in diagnostic studies are not necessarily predictive of the outcome in therapeutic studies.

[0078] The present invention is therefore based on the finding that a specific cancer having CAIX expression can indeed by successfully treated using a radiolabelled antibody for binding to CAIX. Moreover, the inventors have shown a surprising therapeutic advantage when using 21 1 -At-labelled girentuximab for binding to CAIX compared to the antibody labelled with alternative radioisotopes.General definitions

[0079] Throughout this specification, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e. one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects, and vice versa, unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

[0080] Those skilled in the art will appreciate that the present invention is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[0081] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present invention. The present invention is in no way limited to the methods and materials described.

[0082] All of the patents and publications referred to herein are incorporated by reference in their entirety.

[0083] The present invention is not to be limited in scope by the specific examples described herein, which are intended for the purpose of exemplification only. Functionally- equivalent products, compositions and methods are clearly within the scope of the present invention.

[0084] Any example or embodiment of the present invention herein shall be taken to apply mutatis mutandis to any other example or embodiment of the invention unless specifically stated otherwise.

[0085] Unless specifically defined otherwise, all technical and scientific terms used herein shall be taken to have the same meaning as commonly understood by one of ordinary skill in the art (for example, in diagnostic technology, radioimaging, cell culture, molecular genetics, immunology, immunohistochemistry, protein chemistry, and biochemistry).

[0086] The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0087] As used herein, the complementarity determining region sequences (CDRs) of an antigen binding protein or antibody may be defined according to the IMGT, Chothia orKabat numbering systems, or any other CDR numbering system known to the skilled person or described herein.

[0088] As used herein, the term “complementarity determining regions” (syn. CDRs; i.e., CDR1 , CDR2, and CDR3) refers to the amino acid residues of an antibody variable region the presence of which are major contributors to specific antigen binding. Each variable region domain (VH or VL) typically has three CDRs identified as CDR1 , CDR2 and CDR3. The CDRs of VH are also referred to herein as CDR H1 , CDR H2 and CDR H3, respectively, wherein CDR H1 corresponds to CDR 1 of VH, CDR H2 corresponds to CDR 2 of VH and CDR H3 corresponds to CDR 3 of VH. (Alternatively, the CDRs may be named HCDR1 , HCDR2 and HCDR3). Likewise, the CDRs of VL are referred to herein as CDR L1 , CDR L2 and CDR L3, respectively, wherein CDR L1 corresponds to CDR 1 of VL, CDR L2 corresponds to CDR 2 of VL and CDR L3 corresponds to CDR 3 of VL. (Alternatively, the CDRs in the light variable region may be named LCDR1 , LCDR2 and LCDR3)

[0089] "Framework" or "FR" residues are those variable domain residues other than the hypervariable region or CDR residues herein defined. The FRs of VH are also referred to herein as FR H1 , FR H2, FR H3 and FR H4, respectively, wherein FR H1 corresponds to FR 1 of VH, FR H2 corresponds to FR 2 of VH, FR H3 corresponds to FR 3 of VH and FR H4 corresponds to FR 4 of VH. Likewise, the FRs of VL are referred to herein as FR L1 , FR L2, FR L3 and FR L4, respectively, wherein FR L1 corresponds to FR 1 of VL, FR L2 corresponds to FR 2 of VL, FR L3 corresponds to FR 3 of VL and FR L4 corresponds to FR 4 of VL.

[0090] In any embodiment, the amino acid positions assigned to CDRs and FRs may be defined according to Kabat Sequences of Proteins of Immunological Interest, National Institutes of Health, Bethesda, Md., 1987 and 1991 (also referred to herein as “the Kabat numbering system”). It will be appreciated that in accordance with the present invention, the system used to define FRs and CDRs is not limited to the Kabat numbering system, but includes all numbering systems, including the canonical numbering system of Chothia and Lesk J. Mol. Biol. 196: 901 -917, 1987; Chothia et al., Nature 342: 877-883, 1989; and / or Al-Lazikani et al., J. Mol. Biol. 273: 927-948, 1997; the numbering system of Honnegher and Plukthun J. Mol. Biol. 309: 657-670, 2001 ; or the IMGT system discussed in Giudicelli et al., Nucleic Acids Res. 25: 206-211 1997. In another example, the aminoacid positions assigned to CDRs and FRs may be defined according to the Martin (Enhanced Chothia) Numbering Scheme (http: / / www.bioinfo.org.uk / abs / info.html). In some examples, the CDRs may be defined according to the AbM numbering system. The AbM system represents a compromise between the Kabat and Chothia structural loops, and is used by Oxford Molecular's AbM antibody-modeling software. In some examples, the CDRs may be “contact” CDRs. The “contact” CDRs are based on an analysis of the available complex crystal structures.

[0091] In one example, the CDRs are defined according to the Kabat numbering system. Optionally, heavy chain CDR2 according to the Kabat numbering system does not comprise the five C-terminal amino acids listed herein or any one or more of those amino acids are substituted with another naturally-occurring amino acid. In this regard, Padlan et al., FASEB J., 9: 133-139, 1995 established that the five C-terminal amino acids of heavy chain CDR2 are not generally involved in antigen binding.

[0092] The different systems used for assigning CDRs and FRs of an antigen binding domain are well known to the skilled person and are summarised in the below table:

[0093] 1Some of these definitions (particularly for Chothia loops) vary depending on the individual publication examined.

[0094] 2The end of the Chothia CDR H1 loop when numbered using the Kabat numbering convention varies between H32 and H34 depending on the length of the loop. This is because the Kabat numbering scheme places the insertions at H35A and H35B: if neither H35A nor H35B is present, the loop ends at H32; if only H35A ispresent, the loop ends at H33; if both H35A and H35B are present, the loop ends at H34.Urothelial Cancer

[0095] The present invention relates to methods and radiolabelled girentuximab antibody for the treatment of urothelial cancers.

[0096] The urothelial cancer may be bladder, cancer, urethral cancer, ureteral cancer, or renal pelvis cancer.

[0097] In a preferred embodiment, the urothelial cancer is bladder cancer, In any embodiment, the bladder cancer may be:- urothelial carcinoma (80-90% of all bladder cancers) - starts in the urothelial cells lining the bladder wall and is sometimes also called transitional cell carcinoma.- squamous cell carcinoma (about 5% of all bladder cancers) - starts in thin, flat squamous cells in the bladder lining and is more likely to be invasive; this type of cancer may arise in people with a history of bladder inflammation and irritation.- adenocarcinoma (about 1 % of all bladder cancers) - develops from the glandular cells in the bladder and is likely to be invasive.- sarcoma (which usually arises in the bladder muscle) or an aggressive form of bladder cancer such as small cell carcinoma, plasmacytoid carcinoma or micropapillary carcinoma.

[0098] Bladder cancers are also typically categorised as being non-invasive, nonmuscle invasive or muscle-invasive.

[0099] Non-invasive bladder cancer typically comprises tumours in a small section of tissue that is only on or near the surface of the bladder. In any embodiment of the present invention, the bladder cancer may be non-invasive bladder cancer.

[0100] Non-muscle-invasive cancer (NMIBC) refers to bladder cancer that has moved deep into the bladder but has not spread to the muscle. In any embodiment of the present invention, the bladder cancer may be non-muscle-invasive bladder cancer(NMIBC). NMIBC is cancer found in the urothelium (the tissue that lines the inner surface of the bladder).

[0101] Muscle-invasive bladder cancer is bladder cancer that has grown into the bladder wall muscle and may have spread into the fatty layers or tissue on organs outside if the bladder. In any embodiment, of the present invention, the bladder cancer may be muscle-invasive bladder cancer.

[0102] The skilled person will be familiar with typical steps for determining whether a subject has bladder cancer, and is therefore a subject requiring treatment according to the present invention. Diagnostic methods for the detection of bladder cancer include observation of the first symptoms of bladder cancer, such as haematuria, changes in bladder habits, or other symptoms such as pain) or persistent bladder infections and / or determining whether a subject is at risk of bladder cancer. Risk factors for bladder cancer include smoking, radiation exposure, chemotherapy, exposure to certain chemicals (dyes, rubber and textiles and hairdressing supplies), frequent bladder infections and chronic catheter use.

[0103] Diagnosis of bladder cancer typically involves urinalysis, cytology, endoscopic procedures (such as cystoscopy) or imaging procedures such as ultrasound, CT, PET / SPECT or MRI. Transurethral resection of bladder tumour (TURBT) may be used to remove part or all of a bladder tumour for subsequent testing.Carbonic anhydrase IX

[0104] As used herein, carbonic anhydrase is also known as: CA-IX, CA9, CAIX, Carbonate dehydratase IX, Carbonic anhydrase 9, Carbonic anhydrase IX, carbonic dehydratase, G250, Membrane antigen MN, P54 / 58N, pMW1 , RCC-associated antigen G250, RCC-associated protein G250, and Renal cell carcinoma-associated antigen G250.

[0105] Cancer cells primarily express the plasma-membrane-associated CA isoforms CAIX and CAXII, as well as intracellular CAs such as CAI and CAIL Amongst the cancer- related CAs, CAIX has gained most attention, since expression of this isoform in healthy tissue is restricted to epithelial cells in the stomach and gut, but is strongly upregulated in renal cancers.

[0106] CAIX, the expression of which is under control of the hypoxia-inducible factor 1 (HIF-1 ), is predominantly located in chronically hypoxic tumour regions. However, CAIX can also be found in mild hypoxic or even normoxic regions, since the expression of CAIX can be activated by components of the mitogen-activated protein kinase (MAPK) pathway.Girentuximab

[0107] The present invention relates to 21 1 -astatine labelled girentuximab, or an antigen binding fragment thereof, and uses thereof in the methods described herein.

[0108] Girentuximab is an antibody for specifically binding to CAIX and is sometimes referred to as anti-G250 (sometimes also called G250 antibody). Anti-G250 antibodies are, e.g., described in EP-B-0 637336. The antibody or fragment thereof may be chimeric (cG250) or humanised G250 (hG250) antibody. The antibody cG250 is an lgG1 kappa light chain chimeric version of an originally murine monoclonal antibody mG250.

[0109] In some embodiments, the antigen binding protein that binds to or specifically binds to CAIX is as described in any of WO 2002 / 062972 A2 (US 2004 / 0219633 A1 ), WO 2004 / 002526 A1 (US 7,632,496 B2), WO 2006 / 002889 A2 (US 7,691 ,375 B2), WO 2009 / 056342 A1 (US 2014 / 0017252 A1 ), WO 201 1 / 032973 A1 (US 2012 / 0207672 A1 ), and WO 2014 / 128258 A1 (US 10,620,208 B2), or WO 2021 / 000017 A1 , the entire contents of each of these publications is incorporated herein by reference.

[0110] The antibodies for use in the present invention may be produced by any suitable method known in the art including but not limited by methods as described in PCT / EP02 / 01282 and PCT / EP02 / 01283, which are incorporated herein by reference.

[0111] Variants of the original chimeric G250 (cG250) antibody are known, including WX-G250 and WX-G250RIT (Janssen Global Services LLC).

[0112] In any embodiment, the girentuximab antibody or antigen binding fragment thereof comprises:(a) a heavy chain variable domain (VH) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 84, 100, 1 16, 132, 148 or 164.

[0113] In any embodiment, the antibody or antigen binding fragment thereof comprises an antigen binding domain that binds specifically to carbonic anhydrase IX (CAIX) and comprises:FR1 - CDR1 - FR2 - CDR2 - FR3 - CDR3 - FR4 - linker - FR1 a - CDR1 a - FR2a - CDR2a - FR3a - CDR3a - FR4a wherein:FR1 , FR2, FR3 and FR4 are each framework regions;CDR1 , CDR2 and CDR3 are each complementarity determining regions;FR1 a, FR2a, FR3a and FR4a are each framework regions;CDR1 a, CDR2a and CDR3a are each complementarity determining regions; wherein the sequence of any of the complementarity determining regions have an amino acid sequence as described in Table 1 below. Preferably, the framework regions have an amino acid sequence also as described in Table 1 below, including amino acid variation at particular residues which can be determined by aligning the various framework regions derived from each antibody. The CDR1 , CDR2 and CDR3 may be sequences from the VH, CDR1 a, CDR2a and CDR3a may be sequences from VL, or the CDR1 , CDR2 and CDR3 may be sequences from the VL, CDR1 a, CDR2a and CDR3a may be sequences from VH.

[0114] In any embodiment, the antigen or antigen binding fragment thereof comprises:(i) a VH comprising a complementarity determining region (CDR) 1 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence at least about 80%, at least 81 %, at least 82%, at least 83%, atleast 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% or at least 99% identical to a sequence set in SEQ ID NO: 2, and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 3;(ii) a VH comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(iii) a VL comprising a CDR1 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 82 and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 83;(iv) a VL comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 84, 100, 1 16, 132, 148 or 164;(v) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth in SEQ ID NO: 2 and a CDR3 comprising a sequence set forth in SEQ ID NO: 3;(vi) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(vii) a VL comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83;(viii) a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164;(ix) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth between in SEQ ID NO: 2, and a CDR3 comprising a sequence set forth in SEQ ID NO: 3; and a VL comprising a CDR1 comprising a sequence set SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83; or(x) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68 and a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164.

[0115] In a further embodiment, the antibody or antigen binding fragment thereof comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 1 1 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 12, 28, 44, 60 or 76; and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 92, 108, 124, 140, 156 or 172.

[0116] In a further embodiment, the antibody or antigen binding fragment thereof comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consistingof a sequence as set forth in SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 11 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 12, 28, 44, 60 or 76, and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence as set forth in SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 92, 108, 124, 140, 156 or 172.

[0117] In any embodiment, the antibody or antigen binding fragment thereof that specifically binds to CAIX comprises an amino acid sequence that consists essentially of or consists of (in order of N to C terminus or C to N terminus) any one of SEQ ID NO: 4, 20, 36, 52 or 68 and / or any one of SEQ ID NO: 84, 100, 1 16, 132, 148, 164.

[0118] In any embodiment, the antibody or antigen binding fragment thereof comprises:(a) a heavy chain variable domain (VH) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in SEQ ID NOs: 84, 100, 1 16, 132, 148 or 164.

[0119] In any embodiment, the antibody or antigen binding fragment thereof for binding to CAIX may be in the form of:(i) a single chain Fv fragment (scFv);(ii) a dimeric scFv (di-scFv); or(iii) one of (i) or (ii) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.

[0120] In any embodiment, the antibody or antigen binding fragment thereof for binding to CAIX may be in the form of:(i) a diabody;(ii) a triabody;(iii) a tetrabody;(iv) a Fab;(v) a F(ab’)2;(vi) a Fv; or(vii) one of (i) to (vi) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.

[0121] In any embodiment, the antibody or antigen binding fragment thereof for use according to the invention may be a fusion protein comprising an antigen binding protein, immunoglobulin variable domain, antibody, dab (single domain antibody), di-scFv, scFv, Fab, Fab', F(ab')2, Fv fragment, diabody, triabody, tetrabody, linear antibody, single-chain antibody molecule, or multispecific antibody as described herein.

[0122] An antigen binding fragment, immunoglobulin variable domain, antibody, dab, di-scFv, scFv, Fab, Fab', F(ab')2, Fv fragment, diabody, triabody, tetrabody, linear antibody, single-chain antibody molecule, or multispecific antibody, fusion protein or conjugate as described herein may be obtained by expressing a nucleic acid encoding the same.

[0123] An antibody or antigen binding fragment thereof as described herein may comprise a human constant region, e.g., an IgG constant region, such as an IgG 1 , lgG2, lgG3 or lgG4 constant region or mixtures thereof. In the case of an antibody or proteincomprising a VH and a VL, the VH can be linked to a heavy chain constant region and the VL can be linked to a light chain constant region.

[0124] In one example an antibody or antigen binding fragment thereof as described herein comprises a heavy chain constant region, comprising a stabilized heavy chain constant region, comprising a mixture of sequences fully or partially with or without the C-terminal lysine residue.

[0125] In one example, an antibody or antigen binding fragment thereof as described herein comprises a VH disclosed herein linked or fused to an lgG4 constant region or stabilized lgG4 constant region (e.g., as discussed above) and the VL is linked to or fused to a kappa light chain constant region.

[0126] The functional characteristics of an antigen binding fragment thereof as described herein will be taken to apply mutatis mutandis to an antibody as described herein.

[0127] An antibody or antigen binding fragment thereof for a use as described herein may be purified, substantially purified, isolated and / or recombinant.

[0128] Table 1 : Summary of amino acid and nucleotide sequences of preferred CAIX-binding antibodiesConstant regions

[0129] In preferred embodiments, an antibody and / or antigen binding fragment thereof as described herein for use in the present invention may comprise a constant region of an antibody. This includes antigen binding fragments of an antibody fused to an Fc.

[0130] Sequences of constant regions useful for producing the antibodies or antigen binding fragment thereof as described herein may be obtained from a number of different sources. In some examples, the constant region or portion thereof of the protein is derived from a human antibody. The constant region or portion thereof may be derived from any antibody class, including IgM, IgG, IgD, IgA and IgE, and any antibody isotype, including lgG1 , lgG2, lgG3 and lgG4. In one example, the constant region is human isotype lgG4 or a stabilized lgG4 constant region.

[0131] The neonatal Fc-receptor (FcRn) is important for the metabolic fate of antibodies of the IgG class in vivo. The FcRn functions to salvage IgG from the lysosomal degradation pathway, resulting in reduced clearance and increased half-life. It is a heterodimeric protein consisting of two polypeptides: a 50 kDa class I major histocompatibility complex-like protein (a-FcRn) and a 15 kDa p2-microglobulin (|32r|i). FcRn binds with high affinity to the CH2-CH3 portion of the Fc-region of an antibody of the class IgG. The interaction between an antibody of the class IgG and the FcRn is pH dependent and occurs in a 1 :2 stoichiometry, i.e. one IgG antibody molecule can interact with two FcRn molecules via its two heavy chain Fc-region polypeptides (see e.g. Huber, A.H., et al, J. Mol. Biol. 230 (1993) 1077-1083).

[0132] Thus, an IgG’s in vitro FcRn binding properties / characteristics are indicative of its in vivo pharmacokinetic properties in the blood circulation. In the interaction between the FcRn and the Fc-region of an antibody of the IgG class different amino acid residues of the heavy chain CH2- and CH3 -domain are participating.

[0133] Different mutations that influence the FcRn binding and therewith the half-live in the blood circulation are known. Fc-region residues critical to the mouse Fc-region-mouse FcRn interaction have been identified by site-directed mutagenesis (see e.g. Dall'Acqua, W.F., et al. J. Immunol 169 (2002) 5171 -5180). Residues Ile253, H is310, His433, Asn434 and His435 (numbering according to EU index numbering system) are involved in the interaction (Medesan, C, et al., Eur. J. Immunol. 26 (1996) 2533-2536; Firan, M., et al, Int. Immunol. 13 (2001 ) 993-1002; Kim, J.K., et al, Eur. J. Immunol. 24 (1994) 542-548). (Using the Kabat system, the relevant residues are Ile266, His329, His464, Asn465 andHis466). Residues Ile253, His310, and His435 were found to be critical for the interaction of human Fc-region with murine FcRn (Kim, J.K., et al, Eur. J. Immunol. 29 (1999) 2819- 2885).

[0134] More specifically, the antibody or antigen binding protein may comprise one or more amino acid substitutions that decrease the half-life of the protein. For example, the antibody or antigen binding fragment thereof may comprise a Fc region comprising one or more amino acid substitutions that decrease the affinity of the Fc region for the neonatal Fc region (FcRn).Preferred Modifications

[0135] In any embodiment, the antibody or antigen binding fragment thereof (for example a G250 antibody or variant thereof as described herein) is a modified IgG antibody or fragment thereof, comprising a heavy chain constant region having one or more amino acid substitutions compared to a wild-type antibody of the class IgG, wherein the one or more amino acid substitutions reduce the affinity of the antibody for the neonatal Fc receptor (FcRn), thereby reducing the serum half-life of the modified antibody compared to a wild-type antibody of class IgG.

[0136] In one embodiment, the one or more amino acid substitutions are selected from substitutions in the heavy chain constant region 2 (CH2) of the IgG molecule, reducing the affinity of the IgG molecule for FcRn. Alternatively, the one or more amino acid substitutions may be in the heavy chain constant region 3 (CH3) of the IgG molecule, thereby reducing the affinity of the IgG molecule for FcRn. Still further, the amino acid substitutions may include at least one substitution in the CH2 region, and at least one substitution in the CH3 region of the IgG molecule, whereby the substitutions reduce the affinity of the IgG for FcRn.

[0137] In certain preferred embodiments, the one or more amino acid substitutions may be at one or more of residues His310, His433, His435, His436, or Ile253 of IgG. Preferably, the amino acid substitutions comprise a substitution in the heavy chain constant region at positions His310 or at His435. More preferably, the amino acid substitutions that reduce the affinity of the antibody for FcRn are at both His310 and His435.

[0138] In other preferred embodiments, the antibody and / or antigen binding fragment thereof has a constant region substantially identical to a naturally occurring class IgG antibody constant region wherein at least one amino acid residue selected from the group consisting of residues His310, His435, and Ile253 is different from that present in the naturally occurring class IgG antibody, thereby altering FcRn binding affinity and / or serum half-life of said antibody relative to the naturally occurring antibody. In preferred embodiments, the naturally occurring class IgG antibody comprises a heavy chain constant region of a human IgG 1 , lgG2, lgG2M3, lgG3 or lgG4 molecule.

[0139] Also in preferred embodiments, amino acid residue 310 and / or residue 435 from the heavy chain constant region of the antibody having a constant region substantially identical to the naturally occurring class IgG antibody is any amino acid that is not histidine and which reduces the affinity of the constant region for FcRn. For example, the amino acid at residue 310 and / or 435 may be alanine, glutamic acid, aspartic acid, leucine, isoleucine, arginine, proline, glutamine, methionine, serine, threonine, lysine, asparagine, phenylalanine, tyrosine, tryptophan, cysteine, valine or glycine.

[0140] The amino acid substitutions may include substitution from a histidine residue to: alanine, glutamine, glutamic acid or aspartic acid. Preferably, the amino acid substitution at His310 is to alanine. Preferably the amino acid substitution at His435 is to glutamine. Preferably, the amino acid substitution at Ile253 is alanine.

[0141] In a preferred embodiment of the present invention, the binding affinity for FcRn and / or the serum half-life of the modified antibody is decreased by at least about 30%, 50%, 80%, 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, or 100-fold. In a preferred embodiment of the present invention, the binding affinity for FcRn and / or the serum half-life of said modified antibody is reduced by at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97%, 98%, or 99%.

[0142] In addition, the antibodies or fragments thereof for use according to the present invention may be modified to comprise one or more mutations which modify the affinity of the antibodies for any one or more Fc gamma receptors. For example, the one or more amino acid modifications change the affinity of the antibody constant domain, Fc region, or Fc gamma receptor binding fragment, for any one or more Fc gamma receptors.

[0143] In certain embodiments, the modified antibody or antigen binding fragment thereof retains the ability to bind to one or more Fc-gamma receptors and accordingly, in certain embodiments the modified antibody retains the ability to stimulate effector responses (including ADCC). In one example, the Fc region of the constant region contains one or more amino acid substitutions that modulate effector function, including increasing effector function compared to a wild-type IgG.

[0144] In one example, the Fc region of the constant region has a reduced ability to induce effector function, e.g., compared to a native or wild-type human IgG 1 or lgG3 Fc region. In one example, the effector function is antibody-dependent cell-mediated cytotoxicity (ADCC) and / or antibody-dependent cell-mediated phagocytosis (ADCP) and / or complement-dependent cytotoxicity (CDC). Methods for assessing the level of effector function of an Fc region containing protein are known in the art and / or described herein.

[0145] In one example, the amino acid substitution that modifies that ability of the antibody to induce effector function is an amino acid substitution at residue Ile253 from the heavy chain constant region. In one example, the substitution is to any amino acid selected from be alanine, glutamic acid, aspartic acid, leucine, isoleucine, arginine, proline, glutamine, methionine, serine, threonine, lysine, asparagine, phenylalanine, tyrosine, tryptophan, cysteine, valine or glycine, wherein the substitution reduces the ability of the antibody to induce effector function. In preferred embodiments, the substitution from He at residue 253 is to arginine, proline, glutamic acid or aspartate, more preferably alanine.

[0146] In one example, the Fc region is an lgG4 Fc region (i.e., from an lgG4 constant region), e.g., a human lgG4 Fc region. Sequences of suitable lgG4 Fc regions will be apparent to the skilled person and / or available in publicly available databases (e.g., available from National Center for Biotechnology Information).

[0147] In one example, the constant region is a stabilized lgG4 constant region. The term “stabilized lgG4 constant region” will be understood to mean an lgG4 constant region that has been modified to reduce Fab arm exchange or the propensity to undergo Fab arm exchange or formation of a half-antibody or a propensity to form a half antibody. “Fab arm exchange" refers to a type of protein modification for human lgG4, in which an lgG4 heavy chain and attached light chain (half-molecule) is swapped for a heavy-light chainpair from another lgG4 molecule. Thus, lgG4 molecules may acquire two distinct Fab arms recognizing two distinct antigens (resulting in bispecific molecules). Fab arm exchange occurs naturally in vivo and can be induced in vitro by purified blood cells or reducing agents such as reduced glutathione. A “half antibody” forms when an lgG4 antibody dissociates to form two molecules each containing a single heavy chain and a single light chain.

[0148] In one example, a stabilized lgG4 constant region comprises a proline at position 241 of the hinge region according to the system of Kabat (Kabat et al., Sequences of Proteins of Immunological Interest Washington DC United States Department of Health and Human Services, 1987 and / or 1991 ). This position corresponds to position 228 of the hinge region according to the EU numbering system. In human lgG4, this residue is generally a serine. Following substitution of the serine for proline, the lgG4 hinge region comprises a sequence CPPC (SEQ ID NO: 187). In this regard, the skilled person will be aware that the “hinge region” is a proline-rich portion of an antibody heavy chain constant region that links the Fc and Fab regions that confers mobility on the two Fab arms of an antibody. The hinge region includes cysteine residues which are involved in inter-heavy chain disulfide bonds. It is generally defined as stretching from Glu226 to Pro243 of human lgG1 according to the numbering system of Kabat (or Glu216 to Pro230 using the EU index). Hinge regions of other IgG isotypes may be aligned with the IgG 1 sequence by placing the first and last cysteine residues forming inter-heavy chain disulphide (S-S) bonds in the same positions (see for example WO201 0 / 080538).

[0149] In alternative embodiments, the one or more amino acid modifications which reduce the affinity for the FcRn receptor also reduce the affinity for the Fc gamma receptors. The modified antibody or antigen binding fragment thereof may further comprise one or more amino acid substitutions compared a wild-type antibody of the class IgG, wherein the amino acid substitutions further reduce the affinity of the antibody for one or more Fc gamma receptors.

[0150] In a further embodiment, the modified antibody or antigen binding fragment thereof further comprises one or more amino acid substitutions compared a wild-type antibody of the class IgG, wherein the amino acid substitutions increase the stability ofthe CH1 -CH2 hinge region in the modified antibody compared to a wild-type antibody of the class IgG.

[0151] In any embodiment, the heavy chain constant region of the antibody or antigen binding protein comprises amino acid substitutions at both His310 and His435. The antibody may also comprise amino acid substitutions at residues equivalent to Ser228 and Leu235 of the constant heavy chain region.

[0152] In any embodiment, the antibody or antigen binding fragment thereof comprises mutations at Ser228, Leu235, His310 and His435. Preferably, the amino acid modifications are Ser228Pro, Leu235Glu, His310Ala and His435Gln.

[0153] Additional examples of stabilized lgG4 antibodies are antibodies in which arginine at position 409 in a heavy chain constant region of human lgG4 (according to the EU numbering system) is substituted with lysine, threonine, methionine, or leucine (e.g., as described in W02006 / 033386). The Fc region of the constant region may additionally or alternatively comprise a residue selected from the group consisting of: alanine, valine, glycine, isoleucine and leucine at the position corresponding to 405 (according to the EU numbering system). Optionally, the hinge region comprises a proline at position 241 (i.e., a CPPC sequence, SEQ ID NO: 187) (as described above).

[0154] In another example, the Fc region is a region modified to have reduced effector function, i.e., a “non-immunostimulatory Fc region”. For example, the Fc region is an IgG 1 Fc region comprising a substitution at one or more positions selected from the group consisting of 268, 309, 330 and 331. In another example, the Fc region is an lgG1 Fc region comprising one or more of the following changes E233P, L234V, L235A and deletion of G236 and / or one or more of the following changes A327G, A330S and P331 S (Armour et al., Eur J Immunol. 29:2613-2624, 1999; Shields et al., J Biol Chem. 276(9):6591 -604, 2001 ). Additional examples of non-immunostimulatory Fc regions are described, for example, in Dall'Acqua et al., J Immunol. 177 : 1129-1 138 2006; and / or Hezareh J Virol ;75: 12161 -12168, 2001 ).

[0155] In another example, the Fc region is a chimeric Fc region, e.g., comprising at least one CH2 domain from an lgG4 antibody and at least one CH3 domain from an IgG 1 antibody, wherein the Fc region comprises a substitution at one or more amino acid positions selected from the group consisting of 240, 262, 264, 266, 297, 299, 307, 309,323, 399, 409 and 427 (EU numbering) (e.g., as described in WO2010 / 085682). Exemplary substitutions include 240F, 262L, 264T, 266F, 297Q, 299A, 299K, 307P, 309K, 309M, 309P, 323F, 399S, and 427F.

[0156] Preferably, the antibody or antigen binding fragment thereof comprises a heavy chain constant region comprising the sequence as set forth in any one of SEQ ID NOs: 177 to 180, preferably as set forth in SEQ ID NO: 178.

[0157] In a still further embodiment, the antibody or antigen binding fragment thereof preferably comprises a heavy chain comprising the sequence set forth in any one of SEQ ID NOs: 182 to 185, preferably as set forth in SEQ ID NO: 183.

[0158] In any embodiment, the antibody or antigen binding fragment thereof comprises a light chain constant region comprising the amino acid sequence as set forth in SEQ ID NO: 181. Preferably, the antibody or antigen binding protein comprises a light chain comprising the amino acid sequence as set forth in SEQ ID NO: 186.

[0159] In any embodiment, the antibody or antigen binding fragment thereof comprises the sequence set forth in SEQ ID NO: 183 and the sequence set forth in SEQ ID NO: 186.

[0160] In one embodiment, the antibody or antigen binding fragment thereof comprises: a VH comprising a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 36 or 52 and the VL comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 1 16, 132 or 148.

[0161] Preferably, the VH comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 36 or 52 and a VL comprising a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 132 or 148.

[0162] More preferably, the VH comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 36 and the VL comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 148.

[0163] Alternatively, the VH comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 52 and the VL comprises a sequence at least about 95% or 96% or 97% or 98% or 99% identical to, or comprises a sequence set forth in SEQ ID NO: 132 or 148, preferably the sequence set forth in SEQ ID NO: 148.Radiolabelled antibodies

[0164] The skilled person will be familiar with standard methods for conjugating a detectable moiety such as a radionuclide (radiolabel) to an antibody or antigen binding fragment thereof.

[0165] As used herein, the term radionuclide may be used interchangeably with the term radioisotope and radiolabel.

[0166] In any embodiment of the invention, radiolabel may be conjugated to the girentuximab or antigen binding fragment thereof, directly via binding to single or multiple amino acid residues in the protein (e.g. halogenation of tyrosine residues) or indirectly (via a chelating agent or prosthetic group or linker) linked to the radioisotope (ie the radiolabel).

[0167] Examples of methods for astatination of prosthetic groups (such as diaryliodonium salts) are known in the art, for example in WQ2019027059 and WQ20 17 / 089492, incorporated herein in their entirety by cross-reference.

[0168] Examples of suitable chelating agents or linkers may be selected from the group consisting of: TMT (6,6"-bis[N,N",N"'-tetra(carboxymethyl)aminomethyl)-4'-(3-amino-4- methoxyphenyl)-2,2':6',2"-terpyridine), DOTA (1 , 4,7,10-tetraazacyclododecane- NN',N"(N"'-tetraacetic acid, also known as tetraxetan), TCMC (the tetra-primary amide of DOTA), DO3A (1 ,4,7,10-Tetraazacyclododecane-1 ,4,7-tris(acetic acid)-10-(2- thioethyl)acetamide), CB-DO2A (4,10-bis(carboxymethyl)-1 ,4,7,10- tetraazabicyclo[5.5.2]tetradecan), NOTA (1 ,4,7-triazacyclononane-triacetic acid) Diamsar (3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1 ,8-diamine), DTPA (Pentetic acid or diethylenetriaminepentaacetic acid), CHX-A”-DTPA ([(R)-2-Amino-3-(4- isothiocyanatophenyl)propyl]-trans-(S,S)-cyclohexane-1 ,2-diamine-pentaacetic acid), TETA (1 ,4,8,1 1 -tetraazacyclotetradecane-1 ,4,8), 11 -tetraacetic acid, Te2A (4,1 1 - bis(carboxymethyl)-1 ,4,8,11 -tetraazabicyclo[6.6.2]hexadecane), HBED, DFO(Desferrioxamine), DFOsq (DFO-squaramide) and HOPO (3,4,3-(LI-1 ,2-HOPO) or other chelating agent as described herein. Other known chelating moieties include 3p-C-NETA ({4-[2-(bis-carboxy-methylamino)-5-(4-nitrophenyl)pentyl]-7-carbo-xymethyl-[1 ,4,7]triazanonan-1 -yl} acetic acid), 5p-C-NETA (2-({1 -[4,7-b / s(carboxymethyl)-1 ,4,7- triazanonan-1 -yl]-7-(4-nitrophenyl)heptan-2-yl}(carbo-xymethyl) amino)acetic acid), NOTA (1 ,4,7-triazacyclononane-1 ,4,7-triacetic acid) and NODA (1 ,4,7- triazacyclononane-1 ,4-diacetic acid). Further suitable chelating agents (eg comprising DOTA and DFO) are disclosed in WO 2022 / 133537, incorporated herein by reference.

[0169] In any embodiment, radiolabelling of a protein or antibody may be accomplished by covalent iodination, particularly with the lodogen Reagent (1 ,3,4,6-tetrachloro-3a,6a- diphenyl glycoluril). lodogen labeling is a solid phase oxidative method that is similar to the Chloramine-T method, but is generally considered to be milder, since the reaction takes place on the surface of the oxidant, minimizing exposure of the substrate (Salacinzki, P.R.P., et al., AnaLBiochem. 117:136 (1981 )).

[0170] Chelators with radiometals and other halogenated radioisotopes may be bound to antibodies via one or more amino acid residues or reactive moieties in the protein / antibody, including but not limited to one or more lysine residues, tyrosine residues or thiol moieties.

[0171] In another example, the antibody may be conjugated to a bifunctional linker, for example, bromoacetyl, thiols, succinimide ester, TFP ester, a maleimide, or using any amine or thiol- modifying chemistry known in the art.

[0172] The skilled person will be familiar with standard methods for conjugating chelating agents to antibodies and derivatives or fragments thereof. In addition, the skilled person will be familiar with approaches for selecting a relevant chelating agent for pairing with a radiometal, for example as described in Chem. Soc. Rev., 2014,43, 260, incorporated herein by reference.Administration of radiolabelled girentuximab and methods of treatment

[0173] Methods for preparing an antigen binding protein into a suitable form for administration to a subject (e.g. a pharmaceutical composition) are known in the art and include, for example, methods as described in Remington's Pharmaceutical Sciences(18th ed., Mack Publishing Co., Easton, Pa., 1990) and U.S. Pharmacopeia: National Formulary (Mack Publishing Company, Easton, Pa., 1984).

[0174] The radiolabelled girentuximab antibody is usually administered as a pharmaceutical composition with a pharmaceutically acceptable carrier, e.g. physiological saline solution, or other aqueous carrier, optionally comprising a protein stabilizer such as human serum albumin (HSA). The compositions may contain pharmaceutically acceptable auxiliary substances as required to approximate physiological conditions such as pH adjusting and buffering agents, toxicity adjusting agents and the like, for example, sodium acetate, sodium chloride, potassium chloride, calcium chloride, sodium lactate and the like. The concentration of an antigen binding protein according to the present invention, in these formulations can vary widely, and will be selected primarily based on fluid volumes, viscosities, body weight and the like in accordance with the particular mode of administration selected and the patient's needs. Exemplary carriers include water, saline, Ringer's solution, dextrose solution, and 5% human serum albumin. Non-aqueous vehicles such as mixed oils and ethyl oleate may also be used. Liposomes may also be used as carriers. The vehicles may contain minor amounts of additives that enhance isotonicity and chemical stability, e.g., buffers and preservatives.

[0175] Administering refers to the physical introduction of a composition comprising a therapeutic agent to a subject, using any of the various methods and delivery systems known to those skilled in the art including those described herein. Pharmaceutical compositions may be formulated from active agents of the invention as described herein for any appropriate route of administration.

[0176] The radiolabelled girentuximab is preferably administered intravenously, preferably by infusion or intravenous injections. The administration of the antibody by infusion is preferably performed over a period of up to about 30 minutes, more preferably in about 15 minutes. Of course, the radiolabelled girentuximab can also be administered by subcutaneous, intramuscular, intraperitoneal, intrathecal, intraventricular, intrasternal, intracavitary, intravesical and intracranial injection or infusion techniques.

[0177] The phrase ‘therapeutically effective amount’ or ‘effective amount’ generally refers to an amount of a radiolabelled girentuximab or antigen binding fragment thereof that (i) treats the particular disease, condition, or disorder, (ii) attenuates, ameliorates, or eliminates one or more symptoms of the particular disease, condition, or disorder, or (iii)delays the onset of one or more symptoms of the particular disease, condition, or disorder described herein. Undesirable effects, e.g. side effects, are sometimes manifested along with the desired therapeutic effect; hence, a practitioner balances the potential benefits against the potential risks in determining what is an appropriate "effective amount".

[0178] For instance, for the treatment of tumours, a therapeutically effective amount of the radiolabelled antibodies or compositions described herein may inhibit tumour growth by at least about 10%, by at least about 20%, by at least about 30%, by at least about 40%, by at least about 50%, by at least about 60%, by at least about 70%, by at least about 80%, or by at least about 90% or more, relative to untreated subjects. Alternatively, the treatments described herein may cause complete regression of the tumour mass. In other embodiments of the invention, tumour regression can be observed and continue for a period of at least about 10 days, at least about 20 days, at least about 30 days, at least about 40 days, at least about 50 days or at least about 60 days, at least about 70 days, at least about 80 days, at least about 90 days, at least about 100 days or longer.

[0179] A therapeutically effective amount of a drug may also include a “preventative” or “prophylactically effective amount,” which is any amount of the radiolabelled girentuximab or antigen binding fragment thereof administered to a subject at risk of developing a cancer (eg a subject having a pre-malignant condition) or of suffering a recurrence of cancer, that inhibits the development or recurrence of the cancer. In certain embodiments, the prophylactically effective amount prevents the development or recurrence of the cancer entirely. “Inhibiting” or “preventing” the development or recurrence of a cancer means either lessening the likelihood of the cancer's development or recurrence, or preventing the development or recurrence of the cancer entirely.

[0180] The terms "treatment" or "treating" of a subject includes the application or administration of a compound of the invention to a subject with the purpose of delaying, slowing, stabilizing, curing, healing, alleviating, relieving, altering, remedying, less worsening, ameliorating, improving, or affecting the disease or condition, the symptom of the disease or condition, or the risk of (or susceptibility to) the disease or condition. The term "treating" refers to any indication of success in the treatment or amelioration of an injury, pathology or condition, including any objective or subjective parameter such as abatement; remission; lessening of the rate of worsening; lessening severity of the disease; stabilization, diminishing of symptoms or making the injury, pathology orcondition more tolerable to the subject; slowing in the rate of degeneration or decline; making the final point of degeneration less debilitating; or improving a subject's physical or mental well-being.

[0181] As used herein, minimising or preventing the progression of cancer means treating the subject so as to prevent or delay the recurrence or metastasis of a tumour, or to prevent growth of an existing tumour. Minimising or preventing the progression of cancer includes preventing or delaying the recurrence of cancer, or preventing growth of an existing tumour, following treatment of cancer. The recurrence that is being prevented includes a recurrence for example, in the tumour bed, following surgical excision. Alternatively, recurrence includes metastasis of the cancer in another part of the body. The terms “preventing recurrence” and “preventing relapse” as used herein, are interchangeable.

[0182] The present invention also includes methods of preventing the development of cancer in an individual. For example, the individual for whom prevention of cancer is required may be considered to be at risk of developing cancer, but does not yet have detectable cancer. An individual at risk of the development of cancer may be an individual with a family history of cancer, and / or an individual for whom genetic testing or other testing indicates a high risk or high likelihood of the development of cancer. The individual may have cancer stem cells but does not yet have any detectable tumours. It will be understood that methods of preventing the development of cancer include methods of delaying the onset of cancer in a subject.

[0183] In any aspect or embodiment herein, the radiolabelled girentuximab may be administered in combination with (ie sequentially, simultaneously or following) administration of another treatment for the cancer. In any embodiment, the treatment may be any treatment for cancer, optionally selected from: radiosensitising treatment, surgery, immunotherapy (eg Bacillus Calmette-Guerin (BCG)), external beam radiation, chemotherapy, autologous stem cell therapy, or radio-immunotherapy.

[0184] Chemotherapeutic agents are chemical agents or drugs that are selectively destructive to cancer cells and tissues. Chemotherapeutics may include but are not limited to compounds such as, taxane compounds, compounds that act via taxane mechanisms, platinum compounds, anthracycline compounds, antimetabolites, epipodophyllotoxin compounds, camptothecin compounds, or any combination thereof.

[0185] In any aspect of the invention, the radiolabelled girentuximab and the additional treatment for cancer may be administered at the same time. Alternatively, they may be administered sequentially. For instance, the additional therapeutic (eg chemotherapeutic) may be administered prior to the radiolabelled girentuximab or the radiolabelled girentuximab may be administered prior to the additional therapeutic (eg chemotherapeutic). Alternatively, treatment with the additional therapeutic (eg chemotherapeutic) and / or the radiolabelled girentuximab may be staggered.

[0186] The 21 1 -At-girentuximab antibody or antigen binding fragment thereof may be administered as the sole treatment for urothelial cancer or may be administered subsequent to a previous treatment for urothelial cancer (optionally wherein the previous treatment comprises radiosensitising treatment, surgery, chemotherapy, immunotherapy (such as Bacillus Calmette-Guerin (BCG)), external beam radiation, autologous stem cell therapy, or combinations thereof). The 21 1 -At-girentuximab antibody or antigen binding fragment thereof may be administered concomitantly with or sequentially with an additional treatment for cancer (optionally wherein the additional treatment comprises surgery, chemotherapy, immunotherapy, external beam radiation, autologous stem cell therapy, or combinations thereof).

[0187] In any method or use described herein, the subject requiring treatment may have received a previous treatment for urothelial cancer (such as surgery, chemotherapy, immunotherapy (such as Bacillus Calmette-Guerin (BCG)), external beam radiation, autologous stem cell therapy, or combinations thereof), but was not responsive to that prior treatment. In a particularly preferred embodiment, the subject requiring treatment may have received a prior treatment with BCG but was deemed unresponsive to that treatment (in other words, the subject is a “non-responder to BCG” treatment).

[0188] In still further embodiments, the subject requiring treatment may be deemed to be unlikely to respond to BCG treatment (eg as a result of prior screening or diagnostic method).

[0189] Suitable dosages of radiolabelled girentuximab or antigen binding fragment thereof for use according to the present invention will vary depending on the condition to be treated and / or the subject being treated. It is within the ability of a skilled physician to determine a suitable dosage, e.g., by commencing with a sub-optimal dosage and incrementally modifying the dosage to determine an optimal or useful dosage.Alternatively, to determine an appropriate dosage for treatment / prophylaxis, data from the cell culture assays or animal studies are used, wherein a suitable dose is within a range of circulating concentrations that include the ED50 of the active compound with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed and the route of administration utilized. A therapeutically / prophylactically effective dose can be estimated initially from cell culture assays. A dose may be formulated in animal models to achieve a circulating plasma concentration range that includes the IC50 (i.e., the concentration or amount of the compound which achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma maybe measured, for example, by high performance liquid chromatography.

[0190] The skilled person will appreciate that dosage of the antibody for use in accordance with the methods of the invention will depend on various factors including the age, sex, height and weight of the subject to whom the antibody is administered, and depending on the antibody.

[0191] In certain embodiments, the girentuximab may be administered to a subject or infused into a subject, at a dose from about 1 mg to about 50 mg, preferably in a dose from about 5 mg to about 20 mg, and more preferably in a dose of about 10 mg. The specific activity of the radiolabelled antibody may be about 15 to about 1500 MBq / mg, more preferably about 25 to about 1250 MBq / mg, or about 50 to about 1000 MBq / mg or about 75 to about 500 MBq / mg or about 100 to about 250 MBq / mg. In more preferred embodiments, the specific activity of the radiolabelled girentuximab may be from about 50 MBq / mg to about 1000 MBq / mg, such as about 50 MBq / mg, 60 MBq / mg, 70 MBq / mg, 80 MBq / mg, 90 MBq / mg or 100 MBq / mg or about 700 MBq / mg, 800 MBq / mg or about 900 MBq / mg. In particularly preferred embodiments, the specific activity may range from about 70 MBq / mg to about 900 MBq / mg (for example, a specific activity of about 74 MBq / mg or about 888 MBq / mg, to provide a dose of about 1 1 1 MBq or 444 MBq and a mass of antibody of between 0.5 mg and 1 .5 mg).

[0192] In certain embodiments, the radiolabelled girentuximab may be administered at a specific activity of about 60 to about 1400 MBq / mg, preferably between about 80 to 1200 MBq / mg, or about 90 to about 1000 MBq / mg or most preferably about 70 MBq / mgto about 900 MBq / mg (for example, a specific activity of about 74 MBq / mg or about 888 MBq / mg), by intravesical instillation.

[0193] In preferred embodiments, the dose of the radiolabelled girentuximab (or antigen binding fragment thereof) administered is in the range of from about 100 MBq to about 1000 MBq, optionally from about 150 MBq to about 900 MBq, optionally from about 200 MBq to about 800 MBq, optionally from about 300 MBq to about 700 MBq, or optionally from about 400 MBq to about 600 MBq. In particularly preferred embodiments, the radiolabelled antibody is administered at a dose of about 100 MBq, about 200 MBq, about 300 MBq, about 400 MBq, about 500 MBq, about 600 MBq, about 700 MBq, about 800 MBq, about 900 MBq or about 1000 MBq, such as a dose of about 1 10 MBq, about 220 MBq, about 330 MBq, about 440 MBq, about 550 MBq, about 660 MBq, about 770 MBq, about 880 MBq or about 990 MBq.

[0194] In certain embodiments, the radiolabelled girentuximab is administered at a mass dose of about 0.25 to 20 mg, preferably a mass of about 0.5 mg to 10 mg, or 0.5 mg or 5 mg, most preferably, about 0.5 mg or about 1 .5 mg, of girentuximab by slow infusion.

[0195] In some embodiments an effective amount of antibody or antigen binding fragment thereof is administered to the patient identified as having a cancer at a loading dose of about 15 mg / kg, or about 20 mg / kg, or about 25 mg / kg on each of day 1 and day 8 of a first 21 -day cycle or on each of day 1 and day 8 of a first 28-day cycle, followed by administering a standard dose of the antibody or antigen binding fragment thereof to the patient, at about 15 mg / kg, about 20 mg / kg, or about 25 mg / kg on each of day 1 and day 8 of a subsequent 21 -day cycle or on each of day 1 and day 8 of a subsequent 28-day cycle.

[0196] In some embodiments an effective amount of radiolabelled antibody or antigen binding fragment thereof is administered to the patient identified as having a cancer, at a loading volume solution to fill in the cavity. Specifically the volume to fill in the bladder, is around 40 mL. Accordingly, in preferred embodiments, the volume of the radiolabelled antibody or antigen binding fragment thereof administered is about 40 mL.

[0197] In some embodiments, the radiolabelled girentuximab or antigen binding fragment thereof disclosed herein, is continued for a minimum duration of at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, atleast about 5 months, at least about 6 months, at least about 7 months, at least about 8 months, at least about 9 months, at least about 10 months, at least about 11 months, at least about 1 year, at least about 18 months, at least about 24 months, at least about 3 years, at least about 5 years, or at least about 10 years. In some embodiments, treatment with a radiolabelled girentuximab or antigen binding fragment thereof disclosed herein, is continued for a maximum duration of up to about 18 months, 16 months, 14 months, 12 months, 10 months, 8 months, or 6 months. The treatment duration may be from any of these minimum durations to any of these maximum durations, for example from 1 to 18 months.

[0198] In some embodiments, the timing of administration of the radiolabelled girentuximab or antigen binding fragment thereof disclosed herein is staggered such that individual doses are administered at least 1 day apart, at least 2 days apart, at least 3 days apart, at least 4 days apart, at least 5 days apart, at least 6 days apart, or at least 7 days (1 week) apart. The doses may be administered least 1 week apart, at least 2 weeks apart, at least 3 weeks apart, at least 4 weeks apart, at least 5 weeks apart, at least 6 weeks apart, or at least 7 weeks apart. In particularly preferred embodiments, the dose of the radiolabelled girentuximab or antigen binding fragment thereof is administered 1 week apart.

[0199] Accordingly, in any embodiment, the radiolabelled girentuximab or antigen binding fragment thereof may be administered at a dose of about 100 MBq, 200 MBq, 300 MBq, 400 MBq, 500 MBq, 600 MBq, 700 MBq, 800 MBq, 900 MBq or 1000 MBq, such as a dose of about 1 10 MBq, 220 MBq, 330 MBq, 440 MBq, 550 MBq, 660 MBq, 770 MBq, 880 MBq or 990 MBq, preferably a dose of about 1 10 MBq or about 440 MBq, at least 1 day apart, at least 2 days apart, at least 3 days apart, at least 4 days apart, at least 5 days apart, at least 6 days apart, or at least 7 days (1 week) apart.

[0200] More preferably, the radiolabelled girentuximab or antigen binding fragment thereof may be administered at a dose of about 100 MBq, 200 MBq, 300 MBq, 400 MBq, 500 MBq, 600 MBq, 700 MBq, 800 MBq, 900 MBq or 1000 MBq, such as a dose of about 1 10 MBq, 220 MBq, 330 MBq, 440 MBq, 550 MBq, 660 MBq, 770 MBq, 880 MBq or 990 MBq, preferably a dose of about 110 MBq or about 440 MBq, at least 7 days (1 week) apart.

[0201] Even more preferably, the radiolabelled girentuximab or antigen binding fragment thereof may be administered at a dose of about 1 10 MBq or about 440 MBq (such as 1 11 MBq or 444 MBq), at least 7 days (1 week) apart.

[0202] In certain embodiments, the doses may be fractionated in order to provide the total dose amount (such as any of the doses recited above) over a series of administrations. For example, in certain embodiments, the dose of radiolabelled girentuximab may be provided across 2 or 3, or 4 or more administrations. In other words, for a total dose of 1 1 1 MBq, two separate instillations of 55.5 MBq each may be administered to the subject. Similarly, a dose of about 444 MBq may be administered via two separate instillations of about 222 MBq each. The fractionated doses are preferably administered at least 1 day apart, at least 2 days apart, at least 3 days apart, at least 4 days apart, at least 5 days apart, at least 6 days apart, or at least 7 days (1 week) apart. The fractionated doses may be administered least 1 week apart, at least 2 weeks apart, at least 3 weeks apart, at least 4 weeks apart, at least 5 weeks apart, at least 6 weeks apart, or at least 7 weeks apart. In particularly preferred embodiments, the fractionated dose of the radiolabelled girentuximab or antigen binding fragment thereof is administered 1 week apart.

[0203] As used herein, the terms “subject” “individual” and “patient” will be understood to be interchangeable. Although the invention finds application in humans, the invention is also useful for therapeutic veterinary purposes. The invention is useful for domestic or farm animals such as cattle, sheep, horses and poultry; for companion animals such as cats and dogs; and for zoo animals.

[0204] As used herein, the term “about” with respect to a dose, should be understood to include a variation of at least 10% of the recited dose. For example, a dose of “about 400 Mbq” should be understood to include doses of 400 MBq plus or minus up to 40 MBq (in other words, including doses from 360 MBq to 440 MBq, and any intermediates recited in that range). Similarly, a dose of “about 440 MBq” should be understood to include doses of 400 MBq to 480 MBq, and any of the intermediates recited in that range.Kits

[0205] In another embodiment there is provided a kit or article of manufacture including a radiolabelled girentuximab or antigen binding fragment, as described above, preferably provided for use in a method or use outlined herein.

[0206] Optionally the kit further comprises a label or package insert with instructions for use.

[0207] The kit or “article of manufacture” may comprise a container and a label or package insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, blister pack, etc. The containers may be formed from a variety of materials such as glass or plastic. The container holds a therapeutic composition which is effective for treating the condition and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). The label or package insert indicates that the therapeutic composition is used for treating the condition of choice. In one embodiment, the label or package insert includes instructions for use.

[0208] The kit may comprise (a) a therapeutic composition; and (b) a second container with a second active principle or ingredient contained therein. The kit in this embodiment of the invention may further comprise a package insert indicating that the and other active principle can be used to treat a disorder or prevent a complication stemming from cancer. Alternatively, or additionally, the kit may further comprise a second (or third) container comprising a pharmaceutically-acceptable buffer, such as bacteriostatic water for injection (BWFI), phosphate-buffered saline, Ringer's solution and dextrose solution. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, and syringes.

[0209] In certain embodiments the therapeutic composition may be provided in the form of a device, disposable or reusable, including a receptacle for holding the therapeutic composition. In one embodiment, the device is a syringe. The device may hold 1 -2 mL of the therapeutic composition. The therapeutic composition may be provided in the device in a state that is ready for use or in a state requiring mixing or addition of further components.

[0210] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentionedor evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

[0211] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

[0212] The examples that follow are intended to illustrate but in no way limit the present invention.ExamplesExample 1 : Preparation of radiolabelled qirentuximab

[0213] 211At was produced at the Arronax cyclotron facility using the209Bi(a, 2n)211At and recovered in chloroform using a dry-distillation protocol adapted from the procedure previously reported by Lindegren et al (2001 ) Appl. Radiat. Isol, 55: 157-160.

[0214] Radiolabelling of anti-CAIX girentuximab antibody (TLX-250) was performed using bifunctional aryliodonium precursors and according to the procedure described in Guerard et al., 2017, Bioorg. Med. Chem., 25: 5975-5980. The aryl iodonium compound chosen for the study was 3-(Succinimidyloxycarbonyl)phenyl(4-methoxyphenyl) iodonium triflate. It was prepared according to the synthesis scheme developed in the latter literature. Radiolabelling was then performed as described in the literature Guerard et al, in a 2-steps: a) radioastatination of iodonium salts to obtain [211At]SAB, and 2) conjugation to girentuximab. Radiochemical purities were all above 95%.

[0215] Exemplary batch results are provided in the below table:

[0216] Table 2: 21 1 At-girentuximab GMP batch resultsExample 2: Selection of cell line

[0217] CAIX antigen expression was evaluated in a panel of 8 urinary bladder cancer cell lines using Western Blot analysis.

[0218] Table 3: Cell line expression results

[0219] Treatment with 200 mM of C0CI2 was used to induced hypoxia (as determined by the overexpression of HIF-alpha).

[0220] All urothelial cancer cells tested, except one, expressed CAIX antigen in both normoxic and hypoxic conditions.

[0221] The cell line RT112 / 84 was selected for subsequent experiments and was obtained from the ECACC (ECACC reference: 85061 106). After thawing, the cells were grown at 37°C and 5% CO2 in EMEM supplemented with 10% fetal bovine serum and 1% L-Glutamine. Cells were detached and dissociated using Accutase™ solution for binding and cytotoxicity assays.Example 3: Binding of211At-qirentuximab to RT1 12 cells.

[0222] A suspension of RT1 12 cells at 20 x 106cells / mL was prepared in PBS 1X pH 7.4 containing 0.5% (w / v) BSA (sample buffer). For determination of total binding, a serial dilution of211At-girentuximab solution was performed in sample buffer covering the concentration range from 25 nM to 0.10 nM. For determination of non-specific binding, a solution containing 40 nM of211At-girentuximab with 100-fold molar excess of unlabeled antibody, 4 pM, was prepared in sample buffer, then 4-fold dilution series in PBS / BSA 0.5% were performed including 5 dilutions.

[0223] For saturation binding assays, RT1 12 cells (1 x106cells in 50 pL PBS / BSA 0.5%) were incubated in duplicate with increasing concentrations of radiolabelled antibody solution in a final volume of 150 pL for 90 min at room temperature with agitation.

[0224] In parallel, the non-specific binding was determined by incubating five different concentrations of radiolabelled antibody containing an excess of unlabelled antibody (100-fold molar excess). Following incubation, reaction mixtures were overlaid onto 200 pL of a dibutylphtalate oil cushion and centrifuged in microfuge tubes at 12 000 rpm for 3 min. Tubes were frozen in liquid nitrogen and the tips of the tubes containing the cell pellets were cut off for determination of radioactivity using a Gamma counter.

[0225] The results, shown in the below table indicate a high binding affinity of 21 1 -At- GmAb for RT112 cells, with a KD > 0.8 nM. These results also suggest that radiolabelling of GmAb does not substantially effect binding affinity given that the literature reports the affinity of GmAb for CAIX to be approx. 8 nM.

[0226] Table 4: Analysis of binding assays for binding of 211At-GmAb to RT112 cellsExample 4: Comparative analysis of177Lu-GmAb and211At-GmbAb

[0227] In vitro cytotoxicity of211At-girentuximab was compared to that of177Lu-DOTA- girentuximab in the CAIX positive cell line RT1 12.Method

[0228] A working solution at 1000 kBq / mL was prepared by diluting211At-girentuximab (136 MBq / mg; 31.8 MBq / mL) in complete culture medium. The working solution at 1000 kBq / mL was then diluted in complete culture medium by carrying out two-fold serial dilutions in order to cover a concentration range from 1000 to 15.6 kBq / mL.

[0229] A working solution at 40 000 kBq / mL was prepared by diluting the177Lu-DOTA- girentuximab (1005 MBq / mg; 812 MBq / mL) in complete medium. The working solution at 40 000 kBq / mL was then diluted in complete culture medium by carrying out two-fold serial dilutions in order to cover a concentration range from 40 000 kBq / mL to 625 kBq / mL.

[0230] The cytotoxic effect of211At-girentuximab and177Lu-DOTA-girentuximab was evaluated in RT1 12 cells following 2 hour-exposure at 7 different concentrations. The viability of cells was then assessed at two different time points (D2 and D5) using the colorimetric MTS assay, a colorimetric assay for assessing the cell metabolic activity. The method is based on the reduction of MTS compound (3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) by viable cells to generate a colored formazan compound that is soluble in cell culture media. The formazan dye produced by viable cells can be directly quantified by measuring the absorbance at OD= 490 nm.Results

[0231] Survival curves of RT1 12 cells obtained after exposure at different concentrations of a-emitting211At-girentuximab and [3-emitting177Lu-DOTA-Girentuximab on RT112 cell survival are shown in Figure 1. The x-axis is expressed in concentration (volumic activity in MBq / mL) and the y-axis in survival fraction.

[0232] A clear toxicity was observed with activity concentrations over 100 kBq / mL of211At-GmAb. Beginning at that point, a dose-dependent response was observed leading to a significant decrease in the cell viability with more than 80% of cells not surviving at D5 after exposure to a concentration of 1000 kBq / mL. Moreover, differences in survival as observed at D2 and D5 respectively shown that the cytotoxic effect of211At- Girentuximab on RT1 12 cells increases remarkably between D2 and D5.

[0233] For177Lu-DOTA-GmAb-treated cells, a very modest toxicity was observed with activity concentrations over 20 000 kBq / mL and no significant decrease in the cell viability was observed even at the highest concentration. Cell survival was still above 65% after exposure to177Lu-DOTA-Girentuximab at 40 000 kBq / mL.

[0234] 211At-Girentuximab showed markedly greater cytotoxicity than177Lu-DOTA- Girentuximab. Exposure of RT1 12 cells to 1 MBq / mL of211At-girentuximab led to 85% cell death while exposure to 40 MBq / mL of177Lu-Girentuximab led to a very modest cytotoxic effect estimated at about only 45% cell death. The study findings suggest that the a-emitter radioisotope Astatine-211 is more suitable than [3 -emitter radioisotope Lu- 177 in delivering higher dose to the RT112 cell target and most likely close to the cell nucleus due to the more pronounced short-range favorable linear energy transfer of a particles.Example 5: Biodistribution study

[0235] Mice were administered211At-girentuximab, intravesically, and subsequent tissue distribution was assessed,

[0236] Nine female CD-1 mice were divided into groups of 3 (each group representing the 3 different time points for analysis: 30 minutes, 1 hour and 4 hours). Mice were administered about 1200 kBq of211At-girentuximab, into the bladder via a catheter. Mice were sacrificed at 30 minutes, 1 hour and 4 hours and211At activity was measured in various organs and tissues.

[0237] The concentration of radioactivity was expressed as percentage of the injected dose per gram of organ (%ID / g) and as the percentage of the ID for the whole organ.

[0238] The results, shown in Figures 2 and 3, indicate that there is no diffusion of211At- Girentuximab to surrounding organs through the bladder wall.Example 6: Histological study

[0239] Local tolerance following intravesical administration was assessed by histological examination of bladder and kidneys of mice.211At-girentuximab was administered via a catheter into the bladders of 5 female CD-1 mice. Mice were housed for 15 days before sacrifice.

[0240] Examination of histology slides indicate that there were no abnormal observations which could be attributed to the experimental procedure. These results confirm that intravesical instillation of about 700 kBq of211At-girentuximab does not induce toxic side effects. The extrapolation of this dose in mice (700 kBq in 30 pL) corresponds to about 933 MBq in 40 mL for intravesical instillation in humans.Example 7: Internalisation study

[0241] The kinetics of internalisation of125l-girentuximab in the human bladder carcinoma cell, RT 112 was used as a model of the anticipated internalisation properties of211At-girentuximab.

[0242] The release of125l from the cell after internalization of125l-girentuximab, as well as the time125l remains bound to, or internalized in the target cells was also evaluated. The incubation time mimicked the clinical protocol at example 8 below, with a 2h incubation time. A schematic of the assay design is shown in Figure 4.

[0243] The results are shown in Figures 5 and 6. Results from both internalization studies demonstrate that125l-girentuximab is internalized in the target cells and a significant amount of activity remains in the cells even 22h after the wash-out step. This indicates that target cells will be exposed to significant irradiation in a clinical setting.Example 8: Clinical trial

[0244] Orthotopic xenograft mouse models are commonly used to determine likelihood of clinical success. However, in the context of intravesical alpha-therapy this orthotopic xenograft model does not optimally reflect the clinical situation in patients, since it requires non-physiological electrocauterization of the bladder mucosa to promote graft uptake.

[0245] A clinical trial is therefore conducted to assess the safety and efficacy of211At- girentuximab for treating urothelial cancer.

[0246] Preliminary studies of the expression and localization of the CAIX antigen was performed using immunohistochemistry (IHC) on biopsy specimens of 6 patients. Of the 6 patients investigated, 10 biopsy specimens were studied, of which eight were papillary tumours, one was inflammatory mucosa without tumour, and one was inflammatory and scarred bladder wall without tumour. The percentage of tumour cells expressing the CAIX antigen was below 20 and even below in certain instances 10%. Although the global percentage of tumour cells expressing CAIX was low, immunohistochemistry images showed that CAIX expression was markedly more present on the luminal surface of the papillary tumours, directly in contact with the bladder cavity (where the radiolabelled antibody will be instillated).

[0247] A dosimetric calculation given in mGy / MBq was based on the Ml RD formalism and the calculation of cumulative activity in a single source volume, in this case the instilled bladder, with the bladder wall as the single target volume. Calculations were based on a reference geometry (human female and / or male mathematical model defined in the ICRP or ORNL) and involve dose factors S previously calculated by simulation on the models in question and tabulated in the calculation software used: OLINDA 1. (2003) and IDAC-Dose 2.1. (2017).

[0248] Table 5: OLINDA software estimates of absorbed dose equivalent to bladder wall as a function of isotope

[0249] OLINDA 1 software was used to derive the absorbed dose equivalent per unit of activity administered for211At for male and female models. The contribution of 21 1 Po must be added to the calculation, as OLINDA does not consider daughter elements.

[0250] Based on patients with the highest predicted uptake of 9 mSv / MBq (female model), even the highest proposed dose of 370 MBq 21 1 At-GmAb would indicate an estimated dose of (about) 3.39 Gy. This figure is ten times lower than the tolerance dose of 40Gy defined by Meredith et al (2008) Semin. Nucl. Med. 38: 347-357.

[0251] A clinical trial is conducted to assess the safety and the efficacy of211At- girentuximab for treating non-muscle invasive bladder cancer unresponsive to standard of care BCG treatment. The trial is a phase I, first in human trial that evaluates safety, tolerability and preliminary response to211At-Labelled GmAb (211At-TLX250) in patients with non-muscle invasive bladder cancer, refractory to standard treatment.

[0252] The doses of radiotherapy administered are between 100 MBq and 1000 MBq, preferably about 1 1 1 MBq and about 444 MBq.

[0253] The preliminary results will show that patients respond well to treatment with211At-girentuximab with partial or complete response and that tumours are responsive to treatment with an overall reduction in tumour volume following treatment.

[0254] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims

CLAIMS1. A radiolabelled girentuximab antibody, or antigen binding fragment thereof, wherein the antibody or antigen binding fragment is conjugated to the radioisotope 211 - Astatine.

2. The radiolabelled girentuximab antibody or antigen binding fragment thereof, of claim 1 , wherein the radioisotope is directly conjugated to the girentuximab or antigen binding fragment thereof, optionally by halogenation of amino acid residues.

3. The radiolabelled girentuximab antibody or antigen binding fragment thereof, of claim 1 , wherein the radioisotope is indirectly conjugated to the girentuximab or antigen binding fragment thereof, for example via a prosthetic group or other linking moiety.

4. The radiolabelled girentuximab of any one of claims 1 to 3, wherein the antibody or antigen binding fragment thereof, comprises an antigen binding domain that binds specifically to carbonic anhydrase IX (CAIX) and comprises:(a) a heavy chain variable domain (VH) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising three complementarity determining regions (CDRs) of the amino acid sequence as set forth in any of SEQ ID NOs: 84, 100, 116, 132, 148 or 164.

5. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 4, wherein the antibody or antigen binding fragment thereof comprises any one of:(i) a VH comprising a complementarity determining region (CDR) 1 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence at least about 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 least90%, at least 91 %, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to a sequence set in SEQ ID NO: 2, and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 3;(ii) a VH comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(iii) a VL comprising a CDR1 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 82 and a CDR3 comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 83;(iv) a VL comprising a sequence at least about 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% or at least 99% identical to a sequence set forth in SEQ ID NO: 84, 100, 1 16, 132, 148 or 164;(v) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth in SEQ ID NO: 2 and a CDR3 comprising a sequence set forth in SEQ ID NO: 3;(vi) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68;(vii) a VL comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83;(viii) a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164;(ix) a VH comprising a CDR1 comprising a sequence set forth in SEQ ID NO: 1 , a CDR2 comprising a sequence set forth between in SEQ ID NO: 2, and a CDR3 comprising a sequence set forth in SEQ ID NO: 3; and a VL comprising a CDR1 comprising a sequence set SEQ ID NO: 81 , a CDR2 comprising a sequence set forth in SEQ ID NO: 82, and a CDR3 comprising a sequence set forth in SEQ ID NO: 83; or(x) a VH comprising a sequence set forth in any of SEQ ID NO: 4, 20, 36, 52 or 68 and a VL comprising a sequence set forth in any of SEQ ID NO: 84, 100, 116, 132, 148 or 164.

6. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 5, wherein the antibody or antigen binding fragment thereof further comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprisingor consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 1 1 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 12, 28, 44, 60 or 76; and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in any of SEQ ID NoO: 92, 108, 124, 140, 156 or 172; or comprises:(i) a VH comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 9, 25, 41 , 57 or 73; a FR2 comprising or consistingof a sequence as set forth in SEQ ID Nos: 10, 26, 42, 58 or 74; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 11 , 27, 43, 59 or 75; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 12, 28, 44, 60 or 76, and(ii) a VL comprising a framework region (FR) 1 comprising or consisting of a sequence as set forth in SEQ ID Nos: 89, 105, 121 , 137, 153 or 169; a FR2 comprising or consisting of a sequence as set forth in SEQ ID Nos: 90, 106, 122, 138, 154 or 170; a FR3 comprising or consisting of a sequence as set forth in SEQ ID Nos: 91 , 107, 123, 139, 155 or 171 ; a FR4 comprising or consisting of a sequence as set forth in SEQ ID Nos: 92, 108, 124, 140, 156 or 172.

7. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 6, wherein the antibody or antigen binding fragment thereof comprises:(a) a heavy chain variable domain (VH) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in SEQ ID NOs: 4, 20, 36, 52 or 68; and / or(b) a light chain variable domain (VL) comprising or consisting of a sequence at least about 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% identical to a sequence as set forth in SEQ ID NOs: 84, 100, 1 16, 132, 148 or 164.

8. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 7, wherein the antibody or antigen binding fragment thereof comprises an amino acid sequence that consists essentially of or consists of (in order of N to C terminus or C to N terminus) any one of SEQ ID NO: 4, 20, 36, 52 or 68 and / or any one of SEQ ID NO: 84, 100, 116, 132, 148, 164.

9. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 8, wherein the antibody or antigen binding fragment thereof is in the form of:(i) a single domain antibody (sdAb);(ii) a single chain Fv fragment (scFv);(iii) a dimeric scFv (di-scFv); or(iv) one of (ii) or (iii) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.

10. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 8, wherein the girentuximab or antigen binding fragment thereof is in the form of:(i) a minibody;(ii) a diabody;(iii) a triabody;(iv) a tetrabody;(v) a Fab;(vi) a F(ab’)2;(vii) a Fv;(viii) a bispecific antibody or other form of multispecific antibody; or(ix) one of (i) to (viii) linked to a constant region of an antibody, Fc or a heavy chain constant domain (CH) 2 and / or CH3.11 . The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 4 to 10, wherein the linker in the context of the antigen binding domain having FR1 - CDR1 - FR2 - CDR2 - FR3 - CDR3 - FR4 - linker - FR1 a - CDR1 a - FR2a -CDR2a - FR3a - CDR3a - FR4a, is a chemical, one or more amino acids, or a disulphide bond formed between two cysteine residues.

12. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 11 , wherein the girentuximab is in the form of a full IgG antibody.

13. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 12, wherein the girentuximab or antigen binding fragment thereof comprises an Fc region that is engineered to:- have increased in vitro or in vivo half-life;- have an increased capacity to induce antibody-dependent cell mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) or complement-dependent cytotoxicity; and / or- have reduced effector function.

14. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 13 wherein the girentuximab antibody comprises a variable light and variable heavy chain, linked to a constant region of an antibody including a heavy chain CH2 and / or CH3.

15. The radiolabelled girentuximab or antigen binding fragment thereof of claim 14, wherein the girentuximab comprises a heavy chain constant region as defined in any of SEQ ID NO: 177, 178, 179 or 180 and / or a light chain constant region as defined in SEQ ID NO: 181.

16. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 15, wherein the girentuximab comprises a heavy chain as set forth in any of SEQ ID NO: 182, 183, 184, or 185 and / or a light chain as set forth in SEQ ID NO: 186.

17. The radiolabelled girentuximab or antigen binding fragment thereof of any one of claims 1 to 16, wherein the girentuximab comprises one or more amino acid substitutions in the constant regions, so as to reduce the in vivo half-life of the antibody.

18. The radiolabelled girentuximab or antigen binding fragment thereof of claim 17, wherein the girentuximab antibody comprises substitutions at one or more of residuesH is310, His435, Tyr436 and Ile253 (Kabat numbering) of the heavy chain constant regions, thereby altering FcRn binding affinity and / or serum half-life of said antibody (eg relative to an girentuximab that comprises a native CH2 and CH3 domain).

19. The radiolabelled girentuximab or antigen binding fragment thereof of claim 18, wherein the substitutions at the amino acid at position 310 and / or 435 of the antibody are to alanine, glutamic acid, aspartic acid, leucine, isoleucine, arginine, proline, glutamine, methionine, serine, threonine, lysine, asparagine, phenylalanine, tyrosine, tryptophan, cysteine, valine or glycine.

20. The radiolabelled girentuximab or antigen binding fragment thereof of claim 19, wherein the residue at position 310 is selected from alanine, or glutamic acid or glutamine; or the amino acid residue 435 from the heavy chain constant region is selected from arginine, glutamine or alanine.21 . The radiolabelled girentuximab or antigen binding fragment thereof of claim 20, wherein the antibody has an alanine residue at position 310 and glutamine residue at position 435.

22. The radiolabelled girentuximab or antigen binding fragment thereof of claim 21 , wherein the antibody also comprises an amino acid substitution at residue Lys322, preferably wherein the substitution is Lys322Ala.

23. The radiolabelled girentuximab or antigen binding fragment thereof of any one of the preceding claims wherein the antibody comprises the substitutions K322A, H310A and H435Q in the heavy chain constant region.

24. A pharmaceutical composition comprising an 211 -At-girentuximab antibody, or antigen binding fragment thereof of any one of claims 1 to 23, optionally in combination with a pharmaceutically acceptable excipient.

25. A method of treating, preventing or minimising progression of urothelial cancer in a subject, the method comprising: administering to a subject in need thereof, a 211 -At-girentuximab antibody or antigen binding fragment thereof, or pharmaceutical composition of any one of claims 1 to 24,thereby treating, preventing or minimising progression of the urothelial cancer in the subject.

26. A method of minimising, reducing or preventing growth of a urothelial cancer tumour in a subject, the method comprising:- administering to a subject in need thereof, 211 -At-girentuximab antibody or antigen binding fragment thereof, or pharmaceutical composition of any one of claims 1 to 24, thereby minimising, reducing or preventing growth of urothelial cancer in the subject.

27. A method of minimising, reducing or preventing metastasis of urothelial cancer in a subject, the method comprising:- administering to a subject in need thereof, 211 -At-girentuximab antibody or antigen binding fragment thereof, or pharmaceutical composition of any one of claims 1 to 24, thereby minimising, reducing or preventing metastasis of urothelial cancer in the subject.

28. A method of increasing survival of a subject suffering from urothelial cancer, the method comprising:- administering to a subject in need thereof, a 211 -At-girentuximab antibody or antigen binding fragment thereof, or pharmaceutical composition of any one of claims 1 to 24, thereby increasing survival of the subject.

29. Use of 211 -At-girentuximab antibody or antigen binding fragment thereof of any one of claims 1 to 23, in the manufacture of a medicament for: treating, preventing or minimising progression of urothelial cancer in a subject, minimising, reducing or preventing growth of a urothelial cancer tumour in a subject,- minimising, reducing or preventing metastasis of a urothelial cancer in a subject, or- increasing survival of a subject suffering from urothelial cancer.

30. The method or use of any one of claims 25 to 29, wherein the urothelial cancer is bladder cancer, ureteral cancer or urethral cancer.31 . The method or use of any one of claims 25 to 29, wherein the urothelial cancer is bladder cancer.

32. The method or use of any one of claims 25 to 31 , wherein the subject has been deemed to be unresponsive, or likely to be unresponsive to, treatment with Bacillus Calmette-Guerin (BCG).

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