Dose Determining Study of EXS74539 (REC-4539) in Participants With Select Solid Tumors

April 3, 2026 updated by: Exscientia AI Ltd., a wholly owned subsidiary of Recursion Pharmaceuticals, Inc.

A Phase 1, Multicenter, Open-Label, Dose-Escalation Study to Assess Safety, Tolerability, and Efficacy of EXS74539 as Monotherapy in Participants With Select Solid Tumors

The primary purpose of this study is to determine the safety, tolerability, and maximum tolerated dose (MTD) of EXS74539 (REC-4539) in participants with select solid tumors.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Texas
      • Fort Worth, Texas, United States, 76104
        • Recruiting
        • START Dallas
    • Utah
      • West Valley City, Utah, United States, 84119
        • Recruiting
        • START Mountain Region

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.

  • Histologically confirmed diagnosis of the following solid tumors:

    • SCLC
    • High grade neuroendocrine or small cell carcinomas of non-lung origin
    • Non-small cell lung cancer [NSCLC]
    • Prostate cancer
    • Ovarian cancer
    • Renal carcinoma [clear and non-clear cell]
    • Head and neck squamous cell carcinoma
    • Hepatic cancer
    • Gastric cancer
    • Triple-negative breast cancer [TNBC]
  • Participant disease should have progressed, relapsed or the participants should have been intolerant to at least one prior standard systemic therapy for their respective underlying malignancy.
  • Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

Key Exclusion Criteria:

  • Any medical or psychiatric condition that, in the opinion of the Investigator, could jeopardize or would compromise the participant's safety or ability to participate in the study.
  • Symptomatic brain metastases, leptomeningeal metastases, or spinal cord compression due to disease. Participants with brain metastases must be clinically stable and off corticosteroids and anticonvulsants for ≥1 month prior to study treatment and not require any specific intervention for brain metastases.
  • Active and clinically significant infection requiring systemic antibacterial, antiviral, or antifungal therapy <7 days of the first scheduled dose of the study treatment.
  • Significant cardiac abnormalities.
  • Major surgery within 28 days prior to the start of study treatment.

Note: Other protocol-defined inclusion and exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: EXS74539
Drug: EXS74539
Oral administration
Other Names:
  • REC-4539

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)
Time Frame: Up to 3 years
Up to 3 years
Number of Participants with Dose-limiting Toxicity (DLT)
Time Frame: Up to 28 days
Up to 28 days
Number of Participants with Dose Interruptions and Dose Modifications
Time Frame: Up to 3 years
Up to 3 years

Secondary Outcome Measures

Outcome Measure
Time Frame
Overall Survival (OS)
Time Frame: Up to 3 years
Up to 3 years
Progression-free Survival (PFS)
Time Frame: Up to 3 years
Up to 3 years
Objective Response Rate (ORR)
Time Frame: Up to 3 years
Up to 3 years
Maximum Concentration (Cmax) of EXS74539
Time Frame: Cycle 1 Day 25 and at end of treatment (up to approximately 3 years)
Cycle 1 Day 25 and at end of treatment (up to approximately 3 years)
Time to Cmax (tmax) of EXS74539
Time Frame: Cycle 1 Day 25 and at end of treatment (up to approximately 3 years)
Cycle 1 Day 25 and at end of treatment (up to approximately 3 years)
Area Under the Concentration-time Curve From Time Zero to the Time of the Last Quantifiable Concentration (AUC[0-last]) of EXS74539
Time Frame: Cycle 1 Day 1 through end of treatment (up to approximately 3 years)
Cycle 1 Day 1 through end of treatment (up to approximately 3 years)
Duration of Response (DoR)
Time Frame: Up to 3 years
Up to 3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Exscientia AI Ltd., a wholly owned subsidiary of Recursion Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

March 1, 2029

Study Completion (Estimated)

March 1, 2029

Study Registration Dates

First Submitted

March 27, 2026

First Submitted That Met QC Criteria

April 3, 2026

First Posted (Actual)

April 8, 2026

Study Record Updates

Last Update Posted (Actual)

April 8, 2026

Last Update Submitted That Met QC Criteria

April 3, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EXS74539-002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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