A Ph Ib Study of REGN5678 Plus Cemiplimab in Patients With mCRPC

NCT06826768 | Recruiting Phase 1 DMC FDA Drug

• 2 other identifiers: 2024-0326NCI-2025-01092
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

A single-center phase Ib/II dose escalation and dose-expansion clinical trial of REGN5678 plus cemiplimab

Conditions

Prostate Cancer

Outcome Measures

Primary Outcomes (1)

• Safety and Adverse Events (AEs

  Incidence of Adverse Events, Graded According to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version (v) 5.0

  Through study completion; an average of 1 year.

Study Arms (1)

Treatment with REGN5678 Q3W IV + Cemiplimab Q3W IV

EXPERIMENTAL

Patients will receive three weekly doses of REGN5678 as part of a Lead-In Phase and thentransition to every three-week dosing of the combination of REGN5678 and cemiplimab (anti-PD-1).

Drug: REGN5678; Drug: Cemiplimab

Interventions

REGN5678 DRUG

Given by IV infusion

Treatment with REGN5678 Q3W IV + Cemiplimab Q3W IV

Cemiplimab DRUG

Given by IV infusion

Treatment with REGN5678 Q3W IV + Cemiplimab Q3W IV

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Men .18 years of age.
• Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma.
• mCRPC with disease progression after at least two lines of systemic therapy, including one line of second-generation anti-androgen therapy, according to one of the following criteria:
• PSA progression as defined by a rising PSA level confirmed with an interval of \>1 week between each assessment.
• Radiographic disease progression in soft tissue based on RECIST Version 1.1 criteria with PCWG3 modifications with or without PSA progression.
• Radiographic disease progression in bone defined as the appearance of 2 or more new bone lesions on bone scan with or without PSA progression.
• NOTE: Prior approved PSMA-targeted therapies \[e.g. 177Lu-PSMA-617\] and immunotherapy (including sipuleucel-T and immune checkpoint therapies) are permitted.
• Have had either orchiectomy OR be on luteinizing hormone-releasing hormone (LHRH) agonist or antagonist therapy with serum testosterone \<50 ng/dL AND agree to stay on LHRH agonist or antagonist therapy during the study.
• ECOG performance status (PS) grade of 0 or 1.
• Adequate organ and bone marrow function documented by:
• Hemoglobin .8.5 g/dL
• Absolute neutrophil count .1.0 x 109/L
• Platelet count .100 x 109/L
• Serum creatinine .1.5 x ULN or estimated glomerular filtration rate \>50 mL/min/1.73 m2.
• Adequate hepatic function:

You may not qualify if:

• Currently receiving treatment in another interventional study
• Has participated in a study of an investigational drug within 4-weeks of first dose of study therapy.
• Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy.
• NOTE: Prior treatment with sipuleucel-T is permitted
• Patients who have not recovered (ie, grade .1 or baseline) from immune-mediated AEs 3 months prior to initiation of study drug therapy except for endocrinopathies adequately managed with hormone replacement.
• Another malignancy that is progressing or requires active treatment, except:
• Non-melanoma skin cancer that has undergone potentially curative therapy
• Any tumor that has been deemed to be effectively treated with definitive local control (with or without continued adjuvant hormonal therapy)
• Concurrent treatment with systemic corticosteroids (prednisone dose \>10 mg per day or equivalent) or other immunosuppressive drugs \<14 days prior to treatment initiation. Steroids that are topical, inhaled, nasal (spray), or ophthalmic solution are permitted.
• History of or known or suspected autoimmune disease (exception(s): subjects with vitiligo, resolved childhood atopic dermatitis, hypothyroidism, or hyperthyroidism that is clinically euthyroid at screening are allowed).
• Known evidence of an active infection requiring systemic therapy such as human immunodeficiency virus (HIV), active hepatitis, or fungal infection. Testing for hepatitis B and C infection will be performed at screening if not previously performed and documented.
• History of clinically significant cardiovascular disease including, but not limited to:
• Myocardial infarction or unstable angina .6 months prior to treatment initiation
• Clinically significant cardiac arrhythmia
• Deep vein thrombosis, pulmonary embolism, stroke .6 months prior to treatment initiation

Sponsors & Collaborators

• Regeneron Pharmaceuticals: collaborator
• M.D. Anderson Cancer Center: lead

Study Sites (1)

The University of Texas M. D. Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

Related Links

• MD Anderson Cancer Center Website

MeSH Terms

Conditions

Prostatic Neoplasms

Interventions

cemiplimab

Condition Hierarchy (Ancestors)

Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Study Officials

• Bilal Siddiqui, MD

  M.D. Anderson Cancer Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Bilal Siddiqui, MD

CONTACT

(713) 563-4600; basiddiqui@mdanderson.org

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 10, 2025
• First Posted: February 14, 2025
• Study Start: July 9, 2025
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): May 1, 2029
• Last Updated: May 5, 2026

Record last verified: 2026-03

Locations

US (1)