Enrollment in Ph 1/2 Study Discontinued; Development of THE-630 in Patients with GIST Terminated

“We are disappointed that we will not be able to achieve the target exposure for pan-variant inhibition with THE-630, as we continue to believe a therapy with potent activity against all major classes of activating and resistance mutations in KIT has the potential to confer significant clinical benefit, given the unmet need in GIST,” said Tim Clackson, Ph.D., President and Chief Executive Officer of Theseus. “On behalf of the entire Theseus team, I would like to thank the patients, their caregivers, and the investigators and site staff who participated in this study. We remain committed to helping GIST patients with plans to nominate a new, highly selective pan-variant KIT inhibitor candidate for GIST in the first half of 2024. Moving forward, we are excited to have THE-349 as our next near-term clinical program, with its potential best-in-class profile as a fourth generation EGFR inhibitor appropriate for both monotherapy and combination approaches.”