New drug duo aims to shrink Hard-to-Treat prostate tumors

NCT ID NCT03972657

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now This study
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 27, 2026 · Last updated Jul 10, 2026 · Updated 2 times

Summary

This study tests a new drug called REGN5678, given alone or with another drug (cemiplimab), in men with advanced prostate cancer that no longer responds to hormone therapy. The goal is to see if the combination can safely shrink tumors by helping the immune system attack cancer cells. About 345 participants will take part across two phases: first to find the right dose, then to measure tumor response.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
REGN5678 (Nezastomig) and cemiplimab (Libtayo)
What this could lead to
If successful, this could provide a new treatment option for men with advanced prostate cancer that has stopped responding to standard therapies.
What could go wrong
This is an early-phase trial (phase 1/2) with a small number of participants, so safety and effectiveness are not yet proven. Side effects from the immune-boosting drugs could be serious.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 1/2

Runs two stages together: safety and dose first, then whether the treatment works.

Participants

About 345 people

The number the study aims to enrol. It can still change while the study runs.

Started

Aug 2019

Expected to finish

Nov 2027

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 years and older

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Key Inclusion Criteria: mCRPC cohorts (men): 1. Men with histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma. 2. 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. one second-generation anti-androgen therapy (eg, abiraterone, enzalutamide, apalutamide, or darolutamide) 2. 177Lu-PSMA-617 radiotherapy, or another lutetium-based PSMA targeted radioligand, as described in the protocol ccRCC cohorts (men and women): 1. Histologically or cytologically confirmed RCC with a clear-cell component. 2. Diagnosis of metastatic ccRCC with at least one measurable lesion via RECIST 1.1 criteria 3. Has progressed on or after ≥1 line prior systemic therapy approved in the metastatic setting. Prior treatment must include an anti-Programmed Death-1 (receptor) \[PD-1\]/Programmed Death-Ligand 1 (PD-L1) therapy and either ipilimumab and/or a tyrosine kinase inhibitor Key Exclusion Criteria: 1. Has received treatment with an approved systemic therapy within 3 weeks of dosing or has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities, as described in the protocol 2. Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy, as described in the protocol 3. Has received prior PSMA-targeting therapy with the exception of a PSMA targeting radioligand (eg. 177Lu-PSMA-617) in mCRPC 4. Dose Escalation: Has had prior anti-cancer immunotherapy (other than sipuleucel-T) within 5 half-lives prior to study therapy. 5. Dose Expansion (mCRPC only): Has had prior anti-cancer immunotherapy, as described in the protocol 6. Any condition that requires ongoing/continuous corticosteroid therapy (\>10 mg prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose of study therapy 7. Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments, as described in the protocol 8. Encephalitis, meningitis, neurodegenerative disease (with the exception of mild dementia that does not interfere with Activities of Daily Living \[ADLs\]) or uncontrolled seizures in the year prior to first dose of study therapy 9. Uncontrolled infection with Human Immunodeficiency Virus (HIV), hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency NOTE: Other protocol defined Inclusion/Exclusion Criteria apply

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

How to take part

Only the study team decides who joins. These are the ways to reach them.

  1. The places running it

    23 sites. The list below names each one and where it is.

  2. The official record

    ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

    Open the record ↗

  3. A doctor treating you

    A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

  • Banner MD Anderson Cancer Center

    RECRUITING

    Gilbert, Arizona, 85234, United States

  • Columbia University - The Trustees of Columbia University in the City of New York

    RECRUITING

    New York, New York, 10032, United States

  • Emily Couric Clinical Cancer Center

    RECRUITING

    Charlottesville, Virginia, 22908, United States

  • Henry Ford Health

    RECRUITING

    Detroit, Michigan, 48202, United States

  • Icahn School of Medicine at Mount Sinai

    RECRUITING

    New York, New York, 10029, United States

  • James Cancer Hospital and Solove Research Institute

    RECRUITING

    Columbus, Ohio, 43210, United States

  • John Wayne Cancer Institute (JWCI)

    RECRUITING

    Santa Monica, California, 90404, United States

  • Lifespan Cancer Institute

    RECRUITING

    Providence, Rhode Island, 02903, United States

  • MD Anderson Cancer Center

    RECRUITING

    Houston, Texas, 77030, United States

  • Massachusetts General Hospital

    RECRUITING

    Boston, Massachusetts, 02114, United States

  • Mayo Clinic

    RECRUITING

    Phoenix, Arizona, 85054, United States

  • Mayo Clinic

    RECRUITING

    Rochester, Minnesota, 55905, United States

  • Mayo Clinic Jacksonville

    RECRUITING

    Jacksonville, Florida, 32224, United States

  • Moffitt Cancer Center - McKinley Drive

    RECRUITING

    Tampa, Florida, 33612, United States

  • Montefiore Medical Center

    RECRUITING

    New York, New York, 10461, United States

  • NYU Langone Health Perlmutter Cancer Center

    RECRUITING

    New York, New York, 10016, United States

  • Oregon Health & Science University (3485 S. Bond)

    RECRUITING

    Portland, Oregon, 97239, United States

  • Providence Portland Medical Center

    WITHDRAWN

    Portland, Oregon, 97213, United States

  • Sarah Cannon Research Institute (SCRI)

    RECRUITING

    Denver, Colorado, 80218, United States

  • Thomas Jefferson University Hospital

    RECRUITING

    Philadelphia, Pennsylvania, 19107, United States

  • University of Arizona

    RECRUITING

    Tucson, Arizona, 85724, United States

  • University of Rochester Medical Center (URMC) - Wilmot Cancer Institute (WCI) (James P. Wilmot Cancer Center) - Rochester

    RECRUITING

    Rochester, New York, 14642, United States

  • West Virginia University

    RECRUITING

    Morgantown, West Virginia, 26506, United States

  • Yale University Hospital

    RECRUITING

    New Haven, Connecticut, 06510, United States

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