Deciphera Pharmaceuticals, Inc. announced that Nature Medicine has published results from a circulating tumor DNA (ctDNA) analysis of the INTRIGUE Phase 3 study of QINLOCK (ripretinib) in GIST patients with mutations in KIT exon 11 and 17/18 only previously treated with imatinib. INTRIGUE is an international, multi-center study conducted in 122 active sites across 22 countries, where 453 patients in the all patient intent-to-treat population (AP-ITT) with second-line GIST were randomized to receive ripretinib (n=226) or sunitinib (n=227). In the AP-ITT population, QINLOCK demonstrated similar efficacy with a median progression-free survival (PFS) of 8.0 months versus 8.3 months for sunitinib (HR 1.05, nominal p=0.72).

There were fewer patients with Grade 3-4 drug-related treatment emergent adverse events (TEAE) with QINLOCK (26.5%) compared with sunitinib (55.2%). Based on the primary results from the INTRIGUE study, QINLOCK was included in the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology (version 1.2023) as the preferred second-line regimen for patients with advanced GIST who are intolerant to sunitinib. A prespecified exploratory objective in INTRIGUE was to evaluate anti-tumor efficacy of QINLOCK according to baseline KIT primary and secondary mutation status.

Baseline peripheral whole blood was analyzed by Guardant360, a 74-gene ctDNA next-generation sequencing liquid biopsy assay in patients for whom evaluable samples were available (n=362) out of whom 280 patients had detectable ctDNA. In patients with a detectable KIT exon 11 primary mutation (n=157), 52 patients also had mutations in KIT exon 17/18 only and 41 had mutations in KIT exon 13/14 only. Patients with mutations in KIT exon 11 and 17/18 only had improved progression-free survival (PFS), objective response rate (ORR), and overall survival (OS) with QINLOCK versus sunitinib while patients with mutations in KIT exon 11 and 13/14 only had improved PFS, ORR, and OS with sunitinib compared to QINLOCK.