Study of SX-682 Plus Enzalutamide in Men With ARPI-Resistant Metastatic Castration Resistant Prostate Cancer

NCT06228053 | Recruiting Phase 2 FDA Drug

• 2 other identifiers: SX682-CRPC-201R44CA278187
• Study Type: interventional
• Target: 53
• Locations: 1 country
• Sites: 6

Brief Summary

The goal of this clinical trial is to study the combination of SX-682 plus enzalutamide in men with metastatic castration resistant prostate cancer (mCRPC) who have failed prior therapy with androgen receptor pathway inhibitors.

Conditions

Metastatic Castration-resistant Prostate Cancer

Outcome Measures

Primary Outcomes (1)

• Clinical Benefit

  A composite endpoint defined as 1) iRECIST iCR or iPR, 2) PSA50 or 3) stable disease by iRECIST and PCWG3 bone scan criteria for at least 6 months

  Ten 21-day treatment cycles

Secondary Outcomes (3)

• Adverse Events

  Ten 21-day treatment cycles

• Progression-free survival

  Ten 21-day treatment cycles

• Overall survival

  Up to 3 years

Study Arms (1)

SX-682 + enzalutamide

EXPERIMENTAL

Drug: SX-682; Drug: Enzalutamide

Interventions

SX-682 DRUG

Specified dose twice daily

SX-682 + enzalutamide

Enzalutamide DRUG

Specified dose once daily

Also known as: Xtandi

SX-682 + enzalutamide

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Signed and dated Institutional Review Board (IRB)/Independent Ethics Committee (IEC)-approved informed consent form prior to beginning study and undergoing procedures.
• \. Diagnosis of mCRPC with (a) any histology, and (b) currently on or previously on abiraterone/prednisone (or abiraterone/dexamethasone) or darolutamide, apalutamide or enzalutamide with documented progression in either the mCRPC or mHSPC settings, and currently with:
• rising PSA (a rising PSA requires at least 3 measurements obtained at least 1 week apart showing increase from nadir with the last level above 2 ng/mL by local testing); or
• progression of new or existing bone or soft tissue metastatic lesions by CT, MRI or bone scan; no washout necessary.
• Availability of archival tumor tissue for pathologic review and correlative studies. Tumor tissue (localized or metastatic) does not need to be received but rather identified and available (slides and blocks) upon later request for future pathologic review and possible correlative studies.
• Castrate levels of serum total testosterone (\<50 ng/dl) OR ongoing documented ADT.
• Karnofsky performance status of 70 or higher.
• ≥ 18 years of age
• Life expectancy of ≥ 6 months
• Recovered to ≤ Grade 2 toxicity from prior therapy (per CTCAE Version 5.0)
• Adequate bone marrow function:
• Absolute neutrophil count (ANC) ≥ 1.2 × 10\^9/L without any growth factors in prior 7 days
• Hemoglobin ≥ 9.0 g/dL with no blood transfusion in the prior 14 days
• Platelet count ≥ 75 × 10\^9/L with no platelet transfusion in the prior 7 days
• Adequate hepatic function:

You may not qualify if:

• Prior systemic anticancer treatment:
• Prior treatment with docetaxel or marketed antibody within 4 weeks of first dose of study treatment
• Prior radium-223 therapy within 6 weeks
• Prior PSMA-Lu177-617 therapy within 4 weeks
• \. Prior receipt of (a) ketoconazole, (b) 2 or more chemotherapy regimens with docetaxel or (c) any chemotherapy other than docetaxel.
• Current presence of liver metastases on imaging.
• Has received prior radiotherapy within 2 weeks of start of study intervention. Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤2 weeks of radiotherapy) to non-CNS disease.
• Major surgery requiring general anesthesia within 3 weeks of starting study treatment (limited biopsy or line placement is acceptable)
• Has received a live vaccine within 30 days prior to the first dose of study drug. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus Calmette-Guérin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (e.g., FluMist®) are live attenuated vaccines and are not allowed.
• Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study intervention.
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug.
• Congestive heart failure (New York Heart Association Class III or IV) or unstable angina pectoris; previous history of myocardial infarction within one year prior to study entry, uncontrolled hypertension, or uncontrolled arrhythmias.
• Has a history of a second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 2 years.
• Has known active untreated CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are radiologically stable, i.e., without evidence of progression for at least 4 weeks by repeat imaging (note that the repeat imaging should be performed during study screening), clinically stable and without requirement of steroid treatment greater than prednisone 10 mg daily (or equivalent) for at least 14 days prior to first dose of study intervention.
• Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment and is allowed.

Sponsors & Collaborators

• Syntrix Biosystems, Inc.: lead
• National Cancer Institute (NCI): collaborator

Study Sites (6)

University of California, Los Angeles

Los Angeles, California, 90095, United States

RECRUITING

University of California, San Francisco

San Francisco, California, 94143, United States

RECRUITING

University of Michigan

Ann Arbor, Michigan, 48109, United States

RECRUITING

University of Minnesota

Minneapolis, Minnesota, 55455, United States

NOT YET RECRUITING

Duke University

Durham, North Carolina, 27710, United States

RECRUITING

University of Wisconsin

Madison, Wisconsin, 53792, United States

RECRUITING

MeSH Terms

Interventions

enzalutamide

Study Officials

• Syntrix Biosystems

  Syntrix Biosystems, Inc.

  STUDY DIRECTOR

Central Study Contacts

Syntrix Biosystems Clinical Trials

CONTACT

253-833-8009; clinicaltrials@syntrixbio.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 19, 2024
• First Posted: January 29, 2024
• Study Start: November 18, 2024
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2028
• Last Updated: December 22, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

US (6)