Masitinib is safe and effective for the treatment of canine mast cell tumors.
BACKGROUND
Activation of the KIT receptor tyrosine kinase is associated with the development of canine mast cell tumors (MCT).


OBJECTIVE
To evaluate the efficacy of masitinib, a potent and selective inhibitor of KIT, in the treatment of canine MCT.


METHODS
Two hundred and two client-owned dogs with nonmetastatic recurrent or nonresectable grade II or III MCT.


METHODS
Double-blind, randomized, placebo-controlled phase III clinical trial. Dogs were administered masitinib (12.5 mg/kg/d PO) or a placebo. Time-to-tumor progression (TTP), overall survival, objective response at 6 months, and toxicity were assessed.


RESULTS
Masitinib increased overall TTP compared with placebo from 75 to 118 days (P = .038). This effect was more pronounced when masitinib was used as first-line therapy, with an increase in the median TTP from 75 to 253 days (P = .001) and regardless of whether the tumors expressed mutant (83 versus not reached [P = .009]) or wild-type KIT (66 versus 253 [P = .008]). Masitinib was generally well tolerated, with mild (grade I) or moderate (grade II) diarrhea or vomiting as the most common adverse events.


CONCLUSIONS
Masitinib is safe and effective at delaying tumor progression in dogs presenting with recurrent or nonresectable grade II or III nonmetastatic MCT.
Hahn
K A
KA
Gulf Coast Veterinary Specialists, Houston, TX, USA. drhahn87@gmail.com
Ogilvie
G
G
Oglivie
G
G
Rusk
T
T
Devauchelle
P
P
Leblanc
A
A
Legendre
A
A
Powers
B
B
Leventhal
P S
PS
Kinet
J-P
JP
Palmerini
F
F
Dubreuil
P
P
Moussy
A
A
Hermine
O
O
D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001549:Benzamides; D018450:Disease Progression; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004311:Double-Blind Method; D005260:Female; D008297:Male; D034801:Mastocytoma / Q000188:drug therapy / Q000662:veterinary*; D010880:Piperidines; D011725:Pyridines; D013844:Thiazoles / Q000009:adverse effects / Q000627:therapeutic use
D000970:Antineoplastic Agents; D001549:Benzamides; D010880:Piperidines; D011725:Pyridines; D013844:Thiazoles; C526575:masitinib