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

Study 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.

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Key things to know

Main goalTreatment

This describes the study’s primary purpose.

What is being studiedPLX-61639

The study team can explain what participation involves.

Who it may be forNon-small cell lung cancer (NSCLC) · Locally advanced · Metastatic or stage IV

These are broad labels—not an eligibility decision.

Checked against the public recordLast updated Jun 12, 2026 · Source: ClinicalTrials.gov

Is enrollment open?Recruiting

The study is currently accepting participants.

What kind of study?Phase 1

Interventional

Where is it offered?10 U.S. locations

Locations may change over time.

Who runs it?Plexium, Inc.

Study sponsor

Study overview

What this study is about

Purpose: Treatment
Study type: Interventional
Phase: Phase 1
Sponsor: Plexium, Inc.
Interventions being studied: Drug: PLX-61639

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How this study is categorized

These labels come from structured fields and exact terms in the public record.

Cancer type

Non-small cell lung cancer (NSCLC)→

Disease setting

Locally advanced→Metastatic or stage IV→Recurrent or relapsed→Resistant or refractory→

Public criteria

Who may be able to participate

The sponsor separates these requirements into two groups. You do not need to interpret them alone—use them to guide a conversation with the study team.

Requirements people may need to meetInclusion criteria

Key
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

Reasons someone may not be able to joinExclusion 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

Important: This is the sponsor’s public criteria, not a determination of eligibility. The study team must review your individual situation.

Study sites

U.S. locations

Research SiteScottsdale, Arizona
Research SiteDuarte, California
Research SiteOrange, California
Research SiteBoston, Massachusetts
Research SiteSt Louis, Missouri
Research SiteNew York, New York
Research SiteDurham, North Carolina
Research SiteCleveland, Ohio
Research SiteSan Antonio, Texas
Research SiteFairfax, Virginia

Source and freshness
Processed from ClinicalTrials.gov. Last public update: Jun 12, 2026. Always confirm current availability with the study team.

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