Deciphera sets sights on a second marketed drug

After being stymied in attempts to broaden the use of Qinlock, Deciphera is bidding to add a second string to its bow. Its second marketed drug could be vimseltinib, an oral small molecule specific for CSF-1R that today scored a 40% remission rate by independent review, versus 0% for placebo, in the phase 3 Motion study in tenosynovial giant cell tumour. The company says this cancer has a US prevalence of just 9,000, and is currently treated with Daiichi Sankyo’s CSF-1R/Kit/Flt3 inhibitor Turalio and Novartis’s Bcr-Abl inhibitor Gleevec. 25% of Motion patients had failed prior systemic therapy, so the data look slightly worse than uncontrolled phase 2 results showing 64% and 44% ORRs in CSF-1R-naive and pretreated patients respectively. As for toxicity, 10% of vimseltinib-treated patients in Motion had grade 3/4 creatine phosphokinase increases, while 23% had elevated AST (none above grade 2). Deciphera plans regulatory filings in the second quarter of next year. Meanwhile, Qinlock is stalled in fourth-line GIST, a setting where Blueprint’s Ayvakit failed. But Ayvakit secured an exon 18 mutation-positive GIST label, in addition to other cancers, while Qinlock flunked Intrigue, a second-line GIST trial. Deciphera now wants to expand Qinlock into a genetically defined second-line GIST setting.

Clinical-stage small-molecule CSF-1R inhibitors

Note: *also inhibits Kit & Flt3. Source: OncologyPipeline.