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

Purpose

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
  • Non-Small Cell Lung Carcinoma
  • Esophageal Adenocarcinoma
  • SMARCA4 Mutation
  • Gastroesophageal Junction Squamous Cell Carcinoma
  • Advanced Solid Tumor

Eligibility

Eligible Ages
Over 18 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

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

Study Design

Phase
Phase 1
Study Type
Interventional
Allocation
N/A
Intervention Model
Sequential Assignment
Intervention Model Description
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 Purpose
Treatment
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
PLX-61639
  • Drug: PLX-61639
    Orally available degrader of SMARCA2

Recruiting Locations

Research Site
Scottsdale, Arizona 85258

Research Site
St Louis, Missouri 63110

Research Site
Durham, North Carolina 27710

Research Site
Cleveland, Ohio 44106

Research Site
San Antonio, Texas 78229

Research Site
Fairfax, Virginia 22031

More Details

Status
Recruiting
Sponsor
Plexium, Inc.

Study Contact

Clinical Operations
619-631-3091
ClinicalTrials@Plexium.com