Recruiting
Phase 1

PLX-61639

Sponsor:

Plexium, Inc.

Code:

NCT07284186

Conditions

Esophageal Squamous Cell Carcinoma

Gastric Adenocarcinoma

Gastric Squamous Cell Carcinoma

Gastroesophageal Junction (GEJ) Adenocarcinoma

Metastatic Solid Tumor

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

PLX-61639

Study Details

Brief 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.

Conditions

Esophageal Squamous Cell Carcinoma

Gastric Adenocarcinoma

Gastric Squamous Cell Carcinoma

Gastroesophageal Junction (GEJ) Adenocarcinoma

Metastatic Solid Tumor

Study ID

NCT07284186

Start date

Dec 1, 2025

Status verified date

Jun, 2026

Completion date

Sep, 2030

Anticipated

Primary completion date

Dec, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Key Inclusion Criteria:

  • 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

Key Exclusion Criteria:

  • 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

Study Design

Enrollment

155 participants

Anticipated

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: PLX-61639

Interventions

PLX-61639

Orally available degrader of SMARCA2

Primary outcome measure

  • Treatment Emergent Adverse Events [ Time Frame: From enrollment to 28 days after the last dose of PLX-61639 ]
  • Dose-Limiting Toxicities [ Time Frame: From enrollment to 28 days after first dose of PLX-61639 ]

Central Contacts and Locations

Central contacts

Locations

Research Site

Recruiting

Scottsdale, Arizona, United States, 85258

Research Site

Recruiting

Duarte, California, United States, 91010

Research Site

Recruiting

Orange, California, United States, 92868

Research Site

Recruiting

Boston, Massachusetts, United States, 02114

Research Site

Recruiting

St Louis, Missouri, United States, 63110

Research Site

Recruiting

New York, New York, United States, 10044

Research Site

Recruiting

Durham, North Carolina, United States, 27710

Research Site

Recruiting

Cleveland, Ohio, United States, 44106

Research Site

Recruiting

San Antonio, Texas, United States, 78229

Research Site

Recruiting

Fairfax, Virginia, United States, 22031

More Information

Sponsor

Plexium, Inc.

Last update posted

Jun 12, 2026

Last verified

Jun, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Plexium, Inc. on 2026-06-12.