A new phase 3 clinical trial testing the effect of CGT9486 plus sunitinib in patients with gastrointestinal stromal tumors (GIST) is now recruiting participants in the US. 

The open-label international study sponsored by Cogent Biosciences aims to enroll 426 patients, aged 18 or more years, with histologically confirmed locally advanced, metastatic, and/or unresectable GIST.

The trial will consist of 2 parts. In part 1, the dose of an updated formulation of CGT9486 to be used during the rest of the trial will first be evaluated in about 20 participants who have received at least 1 prior line of therapy. The researchers will then evaluate the drug-drug interactions between CGT9486 and sunitinib in around 18 participants who have received at least 2 prior tyrosine kinase inhibitors. 


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In part 2, the efficacy of CGT9486 plus sunitinib will be compared to that of sunitinib alone in around 388 patients who are intolerant to or have failed prior treatment with imatinib only.

The primary outcome measure of part 1 will be the pharmacokinetics of the drug, while that of part 2 will be progression-free survival. The secondary outcome measures for all study parts include the safety of each treatment regimen assessed by the incidence and severity of adverse events, serious adverse events, and change from baseline in laboratory results, as well as overall survival, objective response rate, disease control rate, time to response, and duration of response.

The trial was launched on April 14, 2022. It is expected to be completed in September 2026. 

CGT9486 is a potential best-in-class KIT exon 17 inhibitor that specifically targets KIT mutations in exon 17, which are known to arise as a secondary mutation in GISTs. It has already shown promising clinical activity and safety in a phase 1/2 clinical trial in patients with GIST.

Reference

(Peak) A phase 3 randomized trial of CGT9486+sunitinib vs. sunitinib in subjects with gastrointestinal stromal tumors. ClinicalTrials.gov. January 26, 2022. Updated September 22, 2022. Accessed October 3, 2022.