Pyrrolobenzodiazepines and conjugates thereof

1. A compound which is selected from the group consisting of A:

and B:

where R 10 and R 11 either

(a) form a double bond between the carbon and nitrogen atoms to which they are bound; or

(b) are H and OR A respectively, where R A is selected from H and C 1-4 alkyl;

or a pharmaceutically acceptable salt thereof.

2. A conjugate selected from the group consisting of formula ConjA:

and ConjB:

3. The conjugate according to claim 2 , wherein the cell binding agent is an antibody or an active fragment thereof.

4. The conjugate according to claim 3 , wherein the antibody or antibody fragment is an antibody or antibody fragment for a tumour-associated antigen.

5. The conjugate of claim 3 wherein the antibody or antibody fragment is an antibody which binds to one or more tumor-associated antigens or cell-surface receptors selected from (1)-(88):

(1) BMPR1B;

(2) E16;

(3) STEAP1;

(4) 0772P;

(5) MPF;

(6) Napi3b;

(7) Sema 5b;

(8) PSCA hlg;

(9) ETBR;

(10) MSG783;

(11) STEAP2;

(12) TrpM4;

(13) CRIPTO;

(14) CD21;

(15) CD79b;

(16) FcRH2;

(17) HER2;

(18) NCA;

(19) MOP;

(20) IL20R-alpha;

(21) Brevican;

(22) Eph82R;

(23) ASLG659;

(24) PSCA;

(25) GEDA;

(26) BAFF-R;

(27) CD22;

(28) CD79a;

(29) CXCR5;

(30) HLA-008;

(31) P2X5;

(32) CD72;

(33) LY64;

(34) FcRH1;

(35) IRTA2;

(36) TENB2;

(37) PSMA-FOLH1;

(38) SST;

(38.1) SSTR2;

(38.2) SSTR5;

(38.3) SSTR1;

(38.4) SSTR3;

(38.5) SSTR4;

(39) ITGAV;

(40) ITGB6;

(41) CEACAM5;

(42) MET:

(43) MUC1;

(44) CA9;

(45) EGFRvIII;

(46) CD33;

(47) CD19;

(48) IL2RA;

(49) AXL;

(50) CD30-TNFRSF8;

(51) BCMA-TNFRSF17;

(52) CT Ags-CTA;

(53) CD174 (Lewis Y)-FUT:3;

(54) CLEC 14A;

(55) GRP78-HSPA5;

(56) CD70;

(57) Stem Cell specific antigens;

(58) ASG-5;

(59) ENPP3;

(60) PRR4;

(61) GCC-GUCY2C;

(62) Liv-1-SLC19A6;

(63) 5T4;

(64) CD56-NCMA1;

(65) CanAg;

(66) FOLR1;

(67) GPNMB;

(68) TIM-1-HAVCR1;

(69) RG-1/Prostate tumor target Mindin-Mindin/RG-1;

(70) B7-H4-VTCN1;

(71) PTK7;

(72) CD37;

(73) CD138-SDC1;

(74) CD74;

(75) Claudins-CLs;

(76) EGFR;

(77) Her3:

(78) RON-MST1 R;

(79) EPHA2;

(80) CD20-MS4A1;

(81) Tenascin C-TNC;

(82) FAP;

(83) DKK-1;

(84) CD52:

(85) CS1-SLAMF7;

(86) Endoglin-ENG;

(87) Annexin A1-ANXA1;

(88) V-CAM (CD106)-VCAM1.

6. The conjugate of claim 2 wherein the antibody or antibody fragment is a cysteine-engineered antibody.

7. The conjugate according to claim 2 wherein the drug loading (p) of drugs (D) to antibody (Ab) is an integer from 1 to about 8.

8. The conjugate according to claim 7 , wherein p is 1, 2, 3, or 4.

9. The conjugate according to claim 7 comprising a mixture of the antibody-drug conjugate compounds, wherein the average drug loading per antibody in the mixture of antibody-drug conjugate compounds is about 2 to about 5.

10. A pharmaceutical composition comprising the conjugate of claim 2 and a pharmaceutically acceptable diluent, carrier or excipient.

11. The pharmaceutical composition of claim 10 further comprising a therapeutically effective amount of a chemotherapeutic agent.

12. A method of treating cancer comprising administering to a patient the pharmaceutical composition of claim 11 , wherein the cancer is chronic myeloid leukemia.

13. A method of preparing a conjugate according to claim 2 , the method comprising the step of reacting a cell binding agent with compound A or B as defined below A:

and B:

where R 10 and R 11 either

(a) form a double bond between the carbon and nitrogen atoms to which they are bound; or

(b) are H and OR A respectively, where R A is selected from H and C 1-4 alkyl.

14. A compound according to claim 1 which is:

15. A compound according to claim 1 which is:

16. A conjugate according to claim 2 which is of formula ConjA:

17. A conjugate according to claim 2 which is of formula ConjB: