First-in-Human Study of PLX-61639 in Locally Advanced or Metastatic Solid Tumors
A Phase 1, First-in-Human Study of the SMARCA2 Degrader, PLX-61639, in Patients With SMARCA4-Mutated Locally Advanced or Metastatic Solid Tumors
Plexium, Inc.
155 participants
Dec 1, 2025
INTERVENTIONAL
Conditions
Summary
A multicenter, single-arm, first-in-human study to investigate the safety, pharmacokinetics, and preliminary antitumor activity of PLX-61639 in participants with locally advanced or metastatic, relapsed/refractory, SMARCA4-deficient solid tumors who are intolerant of or have failed available, approved therapies. The study will be conducted in 3 parts: dose escalation (Part 1), dose optimization (Part 2), and cohort expansion (Part 3). Each part of the study will consist of a Screening Phase lasting up to 28 days during which participants will be assessed for eligibility, a Treatment Phase beginning on Cycle 1 Day 1 and consisting of consecutive 28-day cycles, an End of Treatment Visit, and a Post-Treatment Follow-Up Phase. Participants will receive their assigned dose of PLX-61639 administered orally, once daily until progression/relapse, intolerance, death, or withdrawal from study treatment by the Investigator or participant.
Eligibility
Inclusion Criteria4
- Participants with locally advanced or metastatic, relapsed/refractory, solid tumors harboring a SMARCA4 loss-of-function mutation that have progressed on, are intolerant of, or not otherwise candidates for available approved therapies
- Adequate liver bone marrow, coagulation, renal, and cardiopulmonary function
- Measurable disease per RECIST 1.1
- ECOG PS of 0 or 1
Exclusion Criteria8
- Germline SMARCA4 mutations
- Known SMARCA2 mutation or loss of expression
- Symptomatic CNS disease
- Prior treatment with another SMARCA2-directed therapy
- History of other malignancies
- Clinically significant heart disease
- Uncontrolled hypertension
- Prolongation of QT interval
Interventions
Orally available degrader of SMARCA2
Locations(10)
View Full Details on ClinicalTrials.gov
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NCT07284186