A Phase 1, First-in-Human Study of the SMARCA2 Degrader, PLX-61639, in Patients With SMARCA4-Mutated Locally Advanced or Metastatic Solid Tumors

What this Trial Is About

Researchers are evaluating the safety, how the body processes the drug, and early antitumor effects of PLX-61639 in people with locally advanced or metastatic solid tumors that have a specific SMARCA4 mutation. These tumors have returned or not responded to approved treatments, and participants must be intolerant of or have failed available therapies. The study is a first-in-human, Phase 1 trial sponsored by Plexium, Inc., aiming to explore this new treatment's potential in a carefully monitored setting. The study is divided into three parts: dose escalation, dose optimization, and cohort expansion. Each part starts with a screening phase lasting up to 28 days to check eligibility. Then participants enter a treatment phase with 28-day cycles, receiving PLX-61639 orally once a day. Treatment continues until the disease progresses, unacceptable side effects occur, the participant passes away, or treatment is stopped by the participant or investigator. Following treatment, there is an end-of-treatment visit and a post-treatment follow-up phase. Participants will undergo assessments throughout the study, including monitoring for side effects and measuring how the drug behaves in the body. Researchers will evaluate treatment emergent adverse events and dose-limiting toxicities from enrollment through 28 days after the last dose. Other measures include tumor response by imaging, time to response, duration of response, and progression-free survival. The average treatment duration is about one year, with safety and effectiveness monitored carefully during and after treatment.

First-in-Human Study of PLX-61639 in Locally Advanced or Metastatic Solid Tumors