OSI-930: a novel selective inhibitor of Kit and kinase insert domain receptor tyrosine kinases with antitumor activity in mouse xenograft models.
OSI-930 is a novel inhibitor of the receptor tyrosine kinases Kit and kinase insert domain receptor (KDR), which is currently being evaluated in clinical studies. OSI-930 selectively inhibits Kit and KDR with similar potency in intact cells and also inhibits these targets in vivo following oral dosing. We have investigated the relationships between the potency observed in cell-based assays in vitro, the plasma exposure levels achieved following oral dosing, the time course of target inhibition in vivo, and antitumor activity of OSI-930 in tumor xenograft models. In the mutant Kit-expressing HMC-1 xenograft model, prolonged inhibition of Kit was achieved at oral doses between 10 and 50 mg/kg and this dose range was associated with antitumor activity. Similarly, prolonged inhibition of wild-type Kit in the NCI-H526 xenograft model was observed at oral doses of 100 to 200 mg/kg, which was the dose level associated with significant antitumor activity in this model as well as in the majority of other xenograft models tested. The data suggest that antitumor activity of OSI-930 in mouse xenograft models is observed at dose levels that maintain a significant level of inhibition of the molecular targets of OSI-930 for a prolonged period. Furthermore, pharmacokinetic evaluation of the plasma exposure levels of OSI-930 at these effective dose levels provides an estimate of the target plasma concentrations that may be required to achieve prolonged inhibition of Kit and KDR in humans and which would therefore be expected to yield a therapeutic benefit in future clinical evaluations of OSI-930.
Garton
Andrew J
AJ
OSI Pharmaceuticals Inc., 1 Bioscience Park Drive, Farmingdale, NY 11735, USA. agarton@osip.com
Crew
Andrew P A
AP
Franklin
Maryland
M
Cooke
Andrew R
AR
Wynne
Graham M
GM
Castaldo
Linda
L
Kahler
Jennifer
J
Winski
Shannon L
SL
Franks
April
A
Brown
Eric N
EN
Bittner
Mark A
MA
Keily
John F
JF
Briner
Paul
P
Hidden
Chris
C
Srebernak
Mary C
MC
Pirrit
Carrie
C
O'Connor
Matthew
M
Chan
Anna
A
Vulevic
Bojana
B
Henninger
Dwight
D
Hart
Karen
K
Sennello
Regina
R
Li
An-Hu
AH
Zhang
Tao
T
Richardson
Frank
F
Emerson
David L
DL
Castelhano
Arlindo L
AL
Arnold
Lee D
LD
Gibson
Neil W
NW
D000284:Administration, Oral; D000818:Animals; D005260:Female; D006801:Humans; D007946:Leukemia, Mast-Cell / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008819:Mice, Nude; D019009:Proto-Oncogene Proteins c-kit / Q000502:physiology*; D011804:Quinolines / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D013876:Thiophenes / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D014183:Transplantation, Heterologous; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors* / Q000502:physiology
C505207:OSI 930; D011804:Quinolines; D013876:Thiophenes; D019009:Proto-Oncogene Proteins c-kit; D040301:Vascular Endothelial Growth Factor Receptor-2