KIT INHIBITORS

1 . A compound of Formula (I):

or a pharmaceutically acceptable salt thereof, wherein:

R 1 and R 1A are each independently selected from H, halogen, and CH 3 ,

or R 1 and R 1A taken together with the carbon to which they are attached form cyclopropyl;

R 2 is selected from C 1-5 alkyl, CD 3 , C 3-6 cycloalkyl, bicyclo[1.1.1]pentane, and 4- to 6-membered heterocycle containing O, wherein said alkyl, cycloalkyl or heterocycle is optionally substituted with 1-3 R 4 ;

each R 4 is independently selected from halogen, CH 3 , C 2-3 alkenyl, OH, CH 2 OH, C 4-6 cycloalkyl, 4- to 6-membered heterocycle containing O, and phenyl, wherein said alkyl, cycloalkyl, heterocycle or phenyl is optionally substituted with OH or NH 2 , C 1-2 alkyl, CH 2 NH 2 , or halogen;

R 3 is C(O)NHR 5 ,

X 1 is NH or O;

X 2 is N or CH;

X 3 is N or CH;

R 5 is selected from H, C 1-3 alkyl, CD 3 , C 3-4 cycloalkyl and bicyclo[1.1.1]pentane, wherein said alkyl, cycloalkyl or bicyclo[1.1.1.]pentane is optionally substituted with 1-2 R 7 ;

each R 7 is independently selected from CN, NH 2 , OH, CH 2 OH, cyclopropyl, pyridinyl, and oxazolyl, or taken together two R 7 attached to the same carbon atom form 4-membered heterocycle containing N;

R 6 is selected from C 1-5 alkyl, CHF 2 , CF 3 , 4- or 5-membered heterocycle containing N or O, and C 3-4 cycloalkyl, wherein said alkyl or heterocycle is optionally substituted with one R 8 ;

R 8 is selected from OH, NR 9 R 9 , OCH 3 , CH 3 and 4-membered heterocycle containing N or O, wherein said alkyl or heterocycle is optionally substituted with one R 10 ;

each R 9 is independently selected from H, CH 3 and CH 2 CF 3 ; and

R 10 is selected from CH 3 and CF 3 .

2 . The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 and R 1A are each independently selected from H, halogen and CH 3 ;

R 2 is selected from C 1-5 alkyl, CD 3 , C 3-6 cycloalkyl and 4- to 6-membered heterocycle containing O, wherein said alkyl, cycloalkyl or heterocycle is optionally substituted with 1-3 R 4 ;

each R 4 is independently selected from halogen, CH 3 , OH, C 4-6 cycloalkyl, 4- to 6-membered heterocycle containing O, and phenyl, wherein said cycloalkyl or phenyl is optionally substituted with OH or NH 2 ;

each R 7 is independently selected from CN, OH, CH 2 OH, cyclopropyl, pyridinyl, and oxazolyl, or taken together two R 7 attached to the same carbon atom form 4-membered heterocycle containing N; and

R 10 is CH 3 .

3 . The compound of claim 1 or 2 , wherein the compound is represented by Formula (II):

or a pharmaceutically acceptable salt thereof.

4 . The compound of claim 1 or 2 , wherein the compound is represented by Formula (III):

or a pharmaceutically acceptable salt thereof.

5 . The compound of claim 3 or 4 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 and R 1A are each independently selected from H, halogen and CH 3 ;

R 2 is selected from C 1-5 alkyl, CD 3 , C 3-4 cycloalkyl and 4- to 6-membered heterocycle containing O, wherein said alkyl, cycloalkyl or heterocycle is optionally substituted with 1-3 R 4 ;

each R 4 is independently selected from halogen, CH 3 and phenyl;

R 5 is selected from H, C 1-3 alkyl, CD 3 , C 3-4 cycloalkyl and bicyclo[1.1.1]pentane, wherein said alkyl, cycloalkyl or bicyclo[1.1.1.]pentane is optionally substituted with 1-2 R 7 ; and

each R 7 is independently selected from CN, OH, CH 2 OH, cyclopropyl, pyridinyl and oxazolyl, or taken together two R 7 attached to the same carbon atom form 4-membered heterocycle containing N.

6 . The compound of any one of claims 3-5 , or a pharmaceutically acceptable salt thereof, wherein R 2 is selected from CH 3 , CD 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , CH 2 CH(CH 3 ) 2 , CH(CH 3 )CH 2 CH 3 , cyclobutyl, cyclopropyl, oxetanyl, tetrahydrofuranyl, tetrahydrofuranyl and tetrahydropyranyl, each of which is optionally substituted with 1-3 R 4 .

7 . The compound of any one of claims 3-5 , or a pharmaceutically acceptable salt thereof, wherein R 2 is selected from

8 . The compound of any one of claims 3-7 , or a pharmaceutically acceptable salt thereof, wherein each R 4 is independently selected from F, CH 3 , cyclobutyl and phenyl.

9 . The compound of any one of claims 3-8 , or a pharmaceutically acceptable salt thereof, wherein R 5 is selected from H, CH 3 , CD 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , cyclobutyl, cyclopropyl and bicylo[1.1.1]pentanyl, wherein said CH 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , cyclobutyl, cyclopropyl or bicylo[1.1.1]pentanyl are optionally substituted with 1-2 R 7 .

10 . The compound of any one of claims 3-9 , or a pharmaceutically acceptable salt thereof, wherein R 5 is selected from

11 . The compound of any one of claims 3-10 , or a pharmaceutically acceptable salt thereof, wherein each R 7 is independently selected from CN, CH 2 OH, cyclopropyl,

or taken together two R 7 attached to the same carbon atom form

12 . The compound of any one of claims 3-11 , or a pharmaceutically acceptable salt thereof, wherein R 1 and R 1A are each independently selected from H, F and CH 3 .

13 . The compound of claim 1 or 2 , wherein the compound is represented by Formula (IV), (V) or (VI):

or a pharmaceutically acceptable salt thereof.

14 . The compound of claim 1 or 2 , wherein the compound is represented by Formula (VII), (VIII), (IX) or (X):

or a pharmaceutically acceptable salt thereof.

15 . The compound of claim 13 or 14 , or a pharmaceutically acceptable salt thereof, wherein:

R 1 and R 1A are each independently selected from H, halogen, and CH 3 ;

R 2 is selected from C 1-3 alkyl, CD 3 , C 3-4 cycloalkyl and 4- to 6-membered heterocycle containing one O, wherein said alkyl, cycloalkyl, or heterocycle is optionally substituted with 1-3 R 4 ;

each R 4 is independently selected from halogen, OH, cyclopropyl, 4- to 6-membered heterocycle containing one O, and phenyl, wherein said cyclopropyl or phenyl is optionally substituted with OH or NH 2 ;

R 6 is selected from C 1-4 alkyl, CHF 2 , CF 3 , 4- or 5-membered heterocycle containing N or O, and C 3-4 cycloalkyl, wherein said alkyl, heterocycle or cycloalkyl is optionally substituted with R 8 ;

R 8 is selected from OH, NR 9 R 9 , OCH 3 , CH 3 and 4-membered heterocycle containing N or 0, wherein said heterocycle is optionally substituted with CH 3 ; and

each R 9 is independently selected from H, CH 3 , and CH 2 CF 3 .

16 . The compound of any one of claims 13-15 , or a pharmaceutically acceptable salt thereof, wherein R 2 is selected from CH 3 , CD 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , cyclobutyl, cyclopropyl, oxetanyl, tetrahydrofuranyl, tetrahydrofuranyl and tetrahydropyranyl, each of which is optionally substituted with 1-3 R 4 .

17 . The compound of any one of claims 13-15 , or a pharmaceutically acceptable salt thereof, wherein R 2 is selected from

18 . The compound of any one of claims 13-17 , or a pharmaceutically acceptable salt thereof, wherein each R 4 is independently selected from F, OH, cyclobutyl, oxetanyl, oxetanyl, phenyl, tetrahydrofuranyl and tetrahydropyranyl, wherein said cyclobutyl, oxetanyl, oxetanyl, phenyl, tetrahydrofuranyl or tetrahydropyranyl is optionally substituted with OH or NH 2 .

19 . The compound of any one of claims 13-17 , or a pharmaceutically acceptable salt thereof, wherein each R 4 is independently selected from F, OH,

wherein represents OH or NH 2 .

20 . The compound of any one of claims 13-19 , or a pharmaceutically acceptable salt thereof, wherein R 6 is selected from CH 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , CH 2 CH(CH 3 ) 2 , C(CH 3 ) 3 , CH 2 CH 2 CH(CH 3 ) 2 , CHF 2 , CF 3 , cyclopropyl, cyclobutyl, azetidinyl, oxetanyl, tetrahydrofuranyl and pyrrolidinyl, each of which is optionally substituted with R 8 .

21 . The compound of any one of claims 13-19 , or a pharmaceutically acceptable salt thereof, wherein R 6 is selected from

22 . The compound of any one of claims 13-21 , or a pharmaceutically acceptable salt thereof, wherein R 8 is selected from OH, OCH 3 , CH 3 , NH 2 , NHCH 3 , N(CH 3 ) 2 , NHCH 2 CF 3 , N(CH 3 )CH 2 CF 3 , azetidinyl, azetidinyl and oxetanyl.

23 . The compound of any one of claims 13-21 , or a pharmaceutically acceptable salt thereof, wherein R 8 is selected from and

24 . The compound of any one of claims 13-23 , or a pharmaceutically acceptable salt thereof, wherein R 1 and R 1A are each independently selected from H, F and CH 3 .

25 . The compound of claim 1 or 2 , wherein the compound is represented by Formula (III) or (VII):

or a pharmaceutically acceptable salt thereof, wherein:

R 1 and R 1A are each independently selected from H, F and CH 3 ;

R 2 is selected from C 1-3 alkyl, CD 3 , C 3-4 cycloalkyl and 4-membered heterocycle containing O, wherein said alkyl is optionally substituted with 1-3 halo;

R 5 is selected from CH 3 , CH 2 CH 3 and cyclopropyl;

R 6 is selected from C 1-5 alkyl, CHF 2 , CF 3 and 4- to 5-membered heterocycle containing O or N, wherein said alkyl or heterocycle is optionally substituted with R 1 ;

R 8 is selected from OH, NR 9 R 9 , OCH 3 , CH 3 and 4-membered heterocycle containing O or N; and

each R 9 is independently selected from H and CH 3 .

26 . The compound of claim 25 , or a pharmaceutically acceptable salt thereof, wherein R 2 is selected from CH 3 , CHF 2 , CF 3 , CD 3 , CH 2 CH 3 , CH 2 CF 3 , CH 2 CH 2 CH 3 , CH(CH 3 ) 2 , CH(CH 3 )CH 2 F, CH(CH 3 )CHF 2 , cyclobutyl, cyclopropyl and

27 . The compound of claim 25 or 26 , or a pharmaceutically acceptable salt thereof, wherein R 6 is selected from CH 3 , CH 2 CH 3 , CH 2 CH 2 CH 3 , CH 2 CH(CH 3 ) 2 , CH 2 CH 2 CH(CH 3 ) 2 , CHF 2 , azetidinyl, oxetanyl, tetrahydrofuranyl and pyrrolidinyl, each of which is optionally substituted with one R 8 .

28 . The compound of claim 25 or 26 , or a pharmaceutically acceptable salt thereof, wherein R 6 is selected from

29 . The compound of at least one claims 25-28 , or a pharmaceutically acceptable salt thereof, wherein R 8 is selected from OH, OCH 3 , NH 2 , NHCH 3 , N(CH 3 ) 2 , CH 3 ,

30 . A compound of Table 1 or a pharmaceutically acceptable salt thereof.

31 . A pharmaceutical composition comprising the compound of any one of claims 1-30 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient.

32 . A method of treating a patient suffering from gastrointestinal stromal tumor (GIST), comprising administering to the patient an effective amount of the compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of claim 31 .

33 . The method of claim 32 , wherein the patient received one or more prior treatments for the GIST.

34 . The method of claim 33 , wherein the GIST progressed after the prior treatment.

35 . The method of claim 34 , wherein the prior treatment comprises administering one or more agents.

36 . The method of claim 35 , wherein the the prior treatment comprises administering imatinib or a pharmaceutically acceptable salt thereof.

37 . The method of claim 35 , wherein the prior treatment comprises administering avapritinib or a pharmaceutically acceptable salt thereof.

38 . The method of claim 34 , wherein the prior treatment comprises administering one or more agents, each independently selected from: imatinib, sunitinib, regorafenib, nilotinib, cabozantinib, pazopanib, ponatinib, dasatinib, binimetinib, vandetanib, famitinib, anlotinib, axitinib, alvocidib, ribocliclib, sorafenib, pexidartinib, olaratumab, crenolanib, avapritinib, ripretinib, bezuclastinib, AZD3229, BLU-263, everolimus and larotrectinib, and pharmaceutically acceptable salts thereof.

39 . The method of any one of claims 32-38 , wherein the GIST is characterized by a tumor with one or more KIT mutations.

40 . The method of claim 39 , wherein the tumor has a primary activating KIT mutation.

41 . The method of claim 39 or 40 , wherein the GIST is characterized by a tumor with one or more KIT mutations, each independently selected from an exon 9 KIT mutation, an exon 11 KIT mutation, an exon 13 KIT mutation and an exon 17 KIT mutation, and combinations thereof.

42 . The method of claim 41 , wherein each of the one or more KIT mutations is independently selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y, D823D, A829P, K642E, V654A and N655K, and combinations thereof.

43 . The method of claim 41 , wherein each of the one or more KIT mutations is independently selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y, D823D, A829P and K642E, and combinations thereof.

44 . The method of claim 41 , wherein the tumor has an exon 9 KIT mutation.

45 . The method of claim 41 , wherein the tumor has an exon 11 KIT mutation.

46 . The method of claim 41 , wherein the tumor has an exon 17 KIT mutation.

47 . The method of claim 46 , wherein the exon 17 KIT mutation is selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y, D823D, and A829P.

48 . The method of claim 46 , wherein the exon 17 KIT mutation is selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y and D823D.

49 . The method of claim 47 or 48 , wherein the exon 17 KIT mutation is D816V.

50 . The method of claim 41 , wherein the tumor has an exon 13 KIT mutation.

51 . The method of claim 50 , wherein the exon 13 KIT mutation is selected from K642E, V654A and N655K, and combinations thereof.

52 . The method of claim 50 , wherein the exon 13 KIT mutation is K642E.

53 . The method of claim 46 , wherein the exon 17 mutation is A829P.

54 . The method of any one of claims 33-53 , wherein the tumor is mutation resistant to the one or more prior treatments.

55 . The method of claim 54 , where the tumor has an imatinib-resistant mutation.

56 . The method of claim 55 , wherein the imatinib-resistant mutation is selected from an exon 13 KIT mutation, an exon 17 KIT mutation and an exon 14 KIT mutation, and combinations thereof.

57 . The method of claim 56 , wherein the imatinib-resistant mutation is an exon 13 KIT mutation.

58 . The method of claim 57 , wherein the exon 13 KIT mutation is V654A or N655K.

59 . The method of claim 56 , wherein the imatinib-resistant mutation is an exon 17 KIT mutation.

60 . The method of claim 59 , wherein the exon 17 KIT mutation is selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y, D823D, and A829P.

61 . The method of claim 59 , wherein the exon 17 KIT mutation is selected from N822K, D816V, D816E, D816F, D816H, D816I, D816Y, D820E, D820Y and D823D.

62 . The method of claim 60 or 61 , wherein the exon 17 KIT mutation is D816V.

63 . The method of claim 60 or 61 , wherein the exon 17 KIT mutation is D816E.

64 . The method of claim 60 , wherein exon 17 KIT mutation is A829P.

65 . The method of claim 56 , wherein the imatinib-resistant mutation is an exon 14 KIT mutation.

66 . The method of claim 65 , wherein the exon 14 KIT mutation is N680K.

67 . The method of claim 54 , wherein the tumor has an exon 17 inhibitor-resistant mutation.

68 . The method of claim 67 , wherein the exon 17 inhibitor is selected from avapritinib, BLU-263, ripretinib, AZD3229 and bezuclastinib, and pharmaceutically acceptable salts thereof.

69 . The method of claim 68 , wherein the exon 17 inhibitor is avapritinib or a pharmaceutically acceptable salt thereof.

70 . The method of claim 67 or 68 , wherein the exon 17 inhibitor-resistant mutation is N655K.

71 . The method of claim 67 or 68 , wherein the exon 17 inhibitor-resistant mutation is N680K.

72 . A method of treating a patient suffering from a malignant disease characterized by an exon 9 KIT mutation, an exon 11 KIT mutation, an exon 13 KIT mutation or an exon 17 KIT mutation, or a combination thereof, comprising administering to the patient an effective amount of the compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition of claim 31 .

73 . The method of claim 72 , wherein the malignant disease is selected from gastrointestinal stromal tumor (GIST), AML (acute myeloid leukemia), melanoma, lung cancer, uterine cancer, astrocytoma, liver cancer, seminoma, renal cell carcinoma, intercranial germ cell tumor, pancreatic cancer and mediastinal B-cell lymphoma.

74 . A method of treating a patient suffering from gastrointestinal stromal tumor (GIST), comprising administering to the patient an effective combination comprising:

a compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 31 , and

at least one additional agent.

75 . The method of claim 74 , wherein the additional agent is an exon 9 KIT inhibitor or exon 11 KIT inhibitor.

76 . The method of claim 74 or 75 , wherein the additional agent is imatinib or a pharmaceutically acceptable salt thereof.

77 . The method of claim 74 , wherein the additional agent is an exon 17 KIT inhibitor.

78 . The method of claim 77 , wherein the additional agent is selected from avapritinib, BLU-263, ripretinib, AZD3229, and bezuclastinib, and pharmaceutically acceptable salts thereof.

79 . A method of treating a patient suffering from a malignant disease characterized by a tumor with an exon 9 KIT mutation, an exon 11 KIT mutation, or an exon 17 KIT mutation, or a combination thereof, comprising:

(a) obtaining a biological sample from the patient;

(b) detecting the presence or absence of an exon 13 KIT mutation or exon 14 KIT mutation; and

(c) administering an effective amount of a compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 31 , to the patient, if the mutation is detected.

80 . The method of claim 79 , comprising (b) detecting the presence or absence of an exon 13 KIT mutation.

81 . The method of claim 80 , wherein the exon 13 KIT mutation is V654A or N655K.

82 . The method of claim 79 , comprising (b) detecting the presence or absence of an exon 14 KIT mutation.

83 . The method of claim 82 , wherein the exon 14 KIT mutation is N680K.

84 . A method of treating a patient suffering from a malignant disease characterized by a tumor with an exon 9 KIT mutation, an exon 11 KIT mutation or an exon 17 KIT mutation, or a combination thereof, comprising administering an effective amount of a compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 31 , to the patient, if an exon 13 KIT mutation or exon 14 KIT mutation is present.

85 . The method of claim 84 , wherein the exon 13 KIT mutation is V654A or N655K.

86 . The method of claim 84 , wherein the exon 14 KIT mutation is N680K.

87 . A method of treating a patient suffering from gastrointestinal stromal tumor (GIST), comprising administering to the patient an effective amount of a compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 31 , wherein the GIST has a mutation resistant to a KIT inhibitor administered to treat GIST with a primary activating mutation in exon 9 or exon 11.

88 . The method of claim 87 , wherein the KIT inhibitor is selected from imatinib, sunitinib, regorafenib, nilotinib, cabozantinib, pazopanib, ponatinib, dasatinib, binimetinib, vandetanib, famitinib, anlotinib, axitinib, alvocidib, ribocliclib, sorafenib, pexidartinib, olaratumab, crenolanib, avapritinib, ripretinib, bezuclastinib, AZD3229, BLU-263, everolimus and larotrectinib, and pharmaceutically acceptable salts thereof.

89 . The method of claim 87 or 88 , wherein the KIT inhibitor is imatinib or a pharmaceutically acceptable salt thereof.

90 . The method of any one of claims 87-89 , wherein the mutation is an exon 13 KIT mutation.

91 . The method of claim 90 , wherein the exon 13 KIT mutation is V654A or N655K.

92 . A method of treating a patient suffering from a primary gastrointestinal stromal tumor (GIST) characterized by a primary activating mutation in exon 9 or exon 11 KIT, comprising administering to the patient: (i) an effective amount of a compound of any one of claims 1-30 , or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 31 ; and ii) an effective amount of a KIT inhibitor effective against GIST with a primary activating mutation in exon 9 or exon 11.

93 . The method of claim 92 , wherein the KIT inhibitor is selected from imatinib, sunitinib, regorafenib, nilotinib, cabozantinib, pazopanib, ponatinib, dasatinib, binimetinib, vandetanib, famitinib, anlotinib, axitinib, alvocidib, ribocliclib, sorafenib, pexidartinib, olaratumab, crenolanib, avapritinib, ripretinib, bezuclastinib, AZD3229, BLU-263, everolimus and larotrectinib, and pharmaceutically acceptable salts thereof.

94 . The method of claim 92 or 93 , wherein the KIT inhibitor is imatinib.