Discovery and Optimization of a Novel Series of Potent Mutant B‑Raf^V600E Selective Kinase Inhibitors

B-Raf represents an attractive target for anticancer therapy and the development of small molecule B-Raf inhibitors has delivered new therapies for metastatic melanoma patients. We have discovered a novel class of small molecules that inhibit mutant B-Raf^V600E kinase activity both in vitro and in vivo. Investigations into the structure–activity relationships of the series are presented along with efforts to improve upon the cellular potency, solubility, and pharmacokinetic profile. Compounds selectively inhibited B-Raf^V600E in vitro and showed preferential antiproliferative activity in mutant B-Raf^V600E cell lines and exhibited selectivity in a kinase panel against other kinases. Examples from this series inhibit growth of a B-Raf^V600E A375 xenograft in vivo at a well-tolerated dose. In addition, aminoquinazolines described herein were shown to display pERK elevation in nonmutant B-Raf cell lines in vitro

Discovery and Optimization of a Novel Series of Highly Selective JAK1 Kinase Inhibitors

Janus kinases (JAKs) have been demonstrated to be critical in cytokine signaling and have thus been implicated in both cancer and inflammatory diseases. The JAK family consists of four highly homologous members: JAK1–3 and TYK2. The development of small-molecule inhibitors that are selective for a specific family member would represent highly desirable tools for deconvoluting the intricacies of JAK family biology. Herein, we report the discovery of a potent JAK1 inhibitor, 24, which displays ∼1000-fold selectivity over the other highly homologous JAK family members (determined by biochemical assays), while also possessing good selectivity over other kinases (determined by panel screening). Moreover, this compound was demonstrated to be orally bioavailable and possesses acceptable pharmacokinetic parameters. In an in vivo study, the compound was observed to dose dependently modulate the phosphorylation of STAT3 (a downstream marker of JAK1 inhibition)