A Phase 1 Study of BPX-601 CAR T-Cell Therapy in Adult Participants With Prostate Cancer That Has Returned, is Resistant to Treatment and Has Spread

A Phase 1, Open-Label, Dose-Escalation Study of BPX-601, an Anti-PSCA CAR T Cell Drug Product, in Relapsed/Refractory Metastatic Castration-Resistant Prostate Cancer

This study will test a study drug called BPX-601, a CAR-T cell product manufactured from the patient's own T-cells, to see if it can help treat advanced prostate cancer. BPX-601 is a drug that is only used in clinical studies.

The study is looking at:

• What side effects BPX-601 might cause
• What is the best dose of BPX-601
• How well BPX-601 may work to destroy prostate cancer

Study Overview

• Status: Not yet recruiting
• Conditions: Prostate Cancer
• Intervention / Treatment: Genetic: BPX-601

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Clinical Trials Administrator; Phone Number: 844-734-6643; Email: clinicaltrials@regeneron.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

1. Histologically or cytologically confirmed diagnosis of hormone-refractory adenocarcinoma of the prostate without pure small cell carcinoma
2. Metastatic, Castration-Resistant Prostate Cancer (mCRPC) with PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening, as defined in the protocol
3. Has received ≥2 lines prior systemic therapy approved in the metastatic and/or castration-resistant setting [in addition to Androgen Deprivation Therapy (ADT)] including at least 1 second-generation anti-androgen therapy (eg, abiraterone, enzalutamide, apalutamide, or darolutamide)
4. Has had either orchiectomy OR is on Luteinizing Hormone-Releasing Hormone (LHRH) agonist or antagonist therapy with serum testosterone <50 ng/dL AND agrees to stay on LHRH agonist or antagonist therapy during the study

Key Exclusion Criteria:

1. Structurally unstable bone lesions suggesting impending fracture
2. Clinical or radiographic evidence of deep vein thrombosis, pulmonary embolism, or other known thromboembolic event that has not been definitively treated. Participants with prior history of coagulopathy must be on low-molecular weight heparin prophylaxis or prophylactic dose of oral anticoagulant and asymptomatic within 4 weeks of the planned BPX-601 infusion
3. Inadequate renal function defined by creatinine clearance <60 mL/min calculated by 24-hour urine collection or using the Cockcroft-Gault formula
4. Inadequate hepatic function defined by Aspartate aminotransferase (AST) and/or Alanine aminotransferase (ALT) >2.5 × ULN or >5 × ULN, if liver metastases, and/or total bilirubin >1.5 × ULN, as described in the protocol
5. Inadequate bone marrow function defined by Absolute Neutrophil Count (ANC) <1.5 × 10^9/L or platelet count <150 × 10^9/L. At least 7 days must have passed since the last dose of filgrastim (or 14 days since the last dose of pegfilgrastim) and at least 7 days must have passed since the last platelet transfusion at the time of ANC or platelet count.

Note: Other protocol-defined Inclusion/Exclusion criteria apply

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: BPX-601 monotherapy	Genetic: BPX-601; Administered per protocol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Occurrence of Treatment Emergent Adverse Events (TEAEs)	Up to 4 years
Occurrence of Dose Limiting Toxicities (DLTs)	Up to Day 28
Occurrence of Adverse Events of Special Interest (AESIs)	Up to 4 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective response		Up to 4 years
Duration of Response (DoR)		Up to 4 years
Disease control		Up to 4 years
≥50% reduction in Prostate-Specific Antigen (PSA50) response		Up to 4 years
PSA90 response		Up to 4 years
Manufacturing feasibility of BPX-601	Determination of the feasibility of manufacturing BPX-601 is measured by the percent of leukapheresis products collected that are able to be manufactured and released for infusion	Up to 4 years

Collaborators and Investigators

• Sponsor: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): March 20, 2031

Study Registration Dates

• First Submitted: April 14, 2026
• First Submitted That Met QC Criteria: April 14, 2026
• First Posted (Actual): April 21, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Metastatic; Castration-Resistant; Relapsed/Refractory (R/R)
• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Pathologic Processes; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Disease Attributes; Neoplastic Processes; Pathological Conditions, Signs and Symptoms; Prostatic Neoplasms; Recurrence; Neoplasm Metastasis
• Other Study ID Numbers: BPX-601-PSA-2540

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

IPD Sharing Time Frame

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

• IPD Sharing Access Criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No