N-pyridinyl acetamide derivatives as inhibitors of the WNT signaling pathway

A method of treating a condition mediated by the Wnt signalling pathway selected from the group consisting of cancer, sarcoma, melanoma, skin cancer, hematological tumors, lymphoma, carcinoma, and leukemia, wherein the method comprises administering to a patient in need thereof a therapeutic amount of a pharmaceutical formulation comprising a compound of formula (III):

• wherein
• X1 and X2 are selected from CR6 and N, provided that one of X1 and X2 is CR6 and the other is N;
• het2 is a 6 membered heteroaryl ring containing 1, 2 or 3 N heteroatoms which may be unsubstituted or substituted, and when substituted the ring is substituted with 1, 2 or 3 groups independently selected at each occurrence from the group consisting of halo, C1-4 alkyl, C1-4 haloalkyl, —ORA1, —NRA1RB1, —CN, and NRA1C(O)RB1;
• het3 is a 6 membered heteroaryl ring containing 1, 2 or 3 N heteroatoms which may be unsubstituted or substituted, and when substituted the ring is substituted with 1, 2 or 3 groups independently selected at each occurrence from the group consisting of halo, C1-4 alkyl, C1-4 haloalkyl, —ORA1, —NRA1RB1, —CN, and NRA1C(O)RB1;
• R1 and R2 are each H;
• R3 is selected from the group consisting of H, C1-4 alkyl, C1-4 haloalkyl, and C3-6 cycloalkyl;
• R4 is independently selected at each occurrence from the group consisting of halo, C1-4 alkyl, C1-4 haloalkyl, —CN, —ORA4, —NRA4RB4, —SO2RA4, C3-6 cycloalkyl and C3-6 halocycloalkyl;
• R5 and R6 are, at each occurrence, independently selected from the group consisting of H, halo, C1-4 alkyl, C1-4 haloalkyl, —ORA2, —NRA2RB2, —CN, —SO2RA2, and C3-6 cycloalkyl;
• m is 1;
• n is selected from 0, 1 or 2;
• and
• RA1, RB1, RA2, RB2, RA4 and RB4 are at each occurrence independently selected from the group consisting of H, C1-4 alkyl, and C1-4 haloalkyl and a pharmaceutically acceptable excipient.