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

NCT ID: NCT07284186

Last Updated: 2025-12-30

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

PHASE1

Total Enrollment

155 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-12-31

Study Completion Date

2030-09-30

Brief Summary

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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.

Detailed Description

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Conditions

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

Study Design

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Allocation Method

NA

Intervention Model

SEQUENTIAL

In Part 1, eligible participants will enroll sequentially in up to 5 escalating PLX-61639 dose cohorts.

In Part 2, participants will be randomized 1:1 to 1 of 2 dose levels at or below the maximally tolerated (or administered) dose evaluated during Part 1.

In Part 3, additional participants will enroll sequentially to 1 dose level selected from Part 2.
Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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PLX-61639

Group Type EXPERIMENTAL

PLX-61639

Intervention Type DRUG

Orally available degrader of SMARCA2

Interventions

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PLX-61639

Orally available degrader of SMARCA2

Intervention Type DRUG

Eligibility Criteria

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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

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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Plexium, Inc.

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Chief Medical Officer

Role: STUDY_DIRECTOR

Plexium, Inc.

Locations

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Research Site

San Antonio, Texas, United States

Site Status RECRUITING

Research Site

Fairfax, Virginia, United States

Site Status RECRUITING

Countries

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United States

Central Contacts

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Clinical Operations

Role: CONTACT

Phone: 619-631-3091

Email: [email protected]

Other Identifiers

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PLX-61639-101

Identifier Type: -

Identifier Source: org_study_id