Solid TumorPhase 1NCT07517198
Dose Determining Study of EXS74539 (REC-4539) in Participants With Select Solid Tumors
A Phase 1 study testing EXS74539 in people with Solid Tumor and Small Cell Lung Cancer (SCLC), run by Exscientia AI Ltd., a wholly owned subsidiary of Recursion Pharmaceuticals, Inc. at 3 sites in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Solid Tumor, Small Cell Lung Cancer (SCLC), High Grade Neuroendocrine Cancer
- What is being tested?
- EXS74539
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 3 sitesUnited States
- Study dates
- 13 Apr 2026to Mar 2029
- Phase
- Phase 1
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
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- 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.
Who cannot join
- 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.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States3 sites, 3 recruiting
- Recruiting
START Dallas
Fort Worth, Texas, 76104
- Recruiting
Start Lacn
Los Angeles, California, 90025
- Recruiting
START Mountain Region
West Valley City, Utah, 84119
About this study
Official title: 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.
- Conditions
- Solid Tumor, Small Cell Lung Cancer (SCLC), High Grade Neuroendocrine Cancer, Small Cell Carcinomas of Non-lung Origin, Non-small Cell Lung Cancer (NSCLC), Prostate Cancer
- Being tested
- EXS74539
- Keywords
- Solid Tumors, Small Cell Lung Cancer (SCLC), High grade neuroendocrine cancer, 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 (HNSCC), Hepatic cancer, Gastric cancer, Triple-negative breast cancer (TNBC), LSD1 inhibitor, EXS74539, REC-4539
- Medical subject headings
- Small Cell Lung Carcinoma, Carcinoma, Non-Small-Cell Lung, Prostatic Neoplasms, Ovarian Neoplasms, Carcinoma, Renal Cell, Margins of Excision, Squamous Cell Carcinoma of Head and Neck, Liver Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EXS74539Drug
Also called REC-4539
Oral administration
| Study group | Role | What they receive |
|---|---|---|
| EXS74539 | Experimental | EXS74539 Receives: Drug: EXS74539 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)
Measured: Up to 3 years
Number of Participants with Dose-limiting Toxicity (DLT)
Measured: Up to 28 days
Number of Participants with Dose Interruptions and Dose Modifications
Measured: Up to 3 years
Secondary outcomes (7)
Maximum Concentration (Cmax) of EXS74539
Measured: Cycle 1 Day 25 and at end of treatment (up to approximately 3 years)
Time to Cmax (tmax) of EXS74539
Measured: 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
Measured: Cycle 1 Day 1 through end of treatment (up to approximately 3 years)
Objective Response Rate (ORR)
Measured: Up to 3 years
Duration of Response (DoR)
Measured: Up to 3 years
Progression-free Survival (PFS)
Measured: Up to 3 years
Overall Survival (OS)
Measured: Up to 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Apr 2026
- Study start13 Apr 2026
- Primary completionMar 2029 (estimated)
- Study completionMar 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Solid TumorStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Exscientia AI Ltd., a wholly owned subsidiary of Recursion Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07517198
- Sponsor's protocol ID
- EXS74539-002
- Status last verified
- Jun 2026
- First submitted
- 27 Mar 2026
- Last updated
- 10 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No