Axl antibody-drug conjugate and its use for the treatment of cancer

An antibody-drug conjugate having the structural general formula (I):

• CBA-(D)n (I)
• wherein CBA is an antibody consisting of 1613F12, or an antigen binding fragment thereof, comprising the three light chain CDRs of sequences SEQ ID No. 1, 2 and 3 and the three heavy chain CDRs of sequences SEQ ID No. 4, 5 and 6;
• n is 1 to 12;
• and D is a drug consisting of a pyrrolobenzodiazepine dimer (PBD dimer) having the formulae (AB) or (AC)
• wherein:
• the dotted lines indicate the optional presence of a double bond between C1 and C2 or C2 and C3;
• R2 is independently selected from H, OH, ═O, ═CH2, CN, R, OR, ═CH—RD, ═C(RD)2, O—SO2—R, CO2R and COR, and optionally further selected from halo or dihalo;
• where RD is independently selected from R, CO2R, COR, CHO, CO2H, and halo;
• R6 and R9 are independently selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, NO2, Me3Sn and halo;
• R7 is independently selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, NO2, Me3Sn and halo;
• R10 is a linker connected to CBA;
• Q is independently selected from O, S and NH;
• R11 is either H, or R or, where Q is O, SO3M, where M is a metal cation;
• R and R′ are each independently selected from optionally substituted C1-12 alkyl, C3-20 heterocyclyl and C5-20 aryl groups, and optionally in relation to the group NRR′, R and R′ together with the nitrogen atom to which they are attached form an optionally substituted 4-, 5-, 6- or 7-membered heterocyclic ring;
• X is O, S or NH;
• R″ is a C3-12 alkylene group, which chain may be interrupted by one or more heteroatoms, e.g. O, S, N(H), NMe and/or aromatic rings, e.g. benzene or pyridine, which rings are optionally substituted;
• and
• wherein R2″, R6″, R7″, R9″, X″, Q″ and R11″ and are as defined according to R2, R6, R7, R9, X, Q and R11 respectively, and RC is a capping group.