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

Plexium, Inc.

Status and phase: Enrolling; Phase 1

Conditions: Non-Small Cell Lung Carcinoma; Gastric Squamous Cell Carcinoma; Gastroesophageal Junction (GEJ) Adenocarcinoma; Advanced Solid Tumor; Gastroesophageal Junction Squamous Cell Carcinoma; Esophageal Squamous Cell Carcinoma; Esophageal Adenocarcinoma; SMARCA4 Mutation; Metastatic Solid Tumor; Gastric Adenocarcinoma

Treatments: Drug: PLX-61639

Study type: Interventional

Funder types: Industry

Identifiers

NCT07284186

PLX-61639-101

Details and patient eligibility

About

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.

Enrollment: 155 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

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

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Sequential Assignment

Masking: None (Open label)

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155 participants in 1 patient group

PLX-61639

Experimental group

Treatment:

Drug: PLX-61639