A Study of Retifanlimab After Chemoradiation in People With Anal Cancer

November 4, 2026 updated by: Memorial Sloan Kettering Cancer Center

A Phase II Trial Evaluating Personalized Anal Squamous Cell Carcinoma Treatment Escalation Using Real-Time ctDNA Surveillance (PACER)

Participants will receive retifanlimab during 28-day treatment Cycles and will continue to receive retifanlimab for up to 6 Cycles (up to 12 Cycles with study doctor approval) unless the participant's cancer comes back, have serious side effects and cannot continue study treatment, or the study doctor thinks it is in the participant's best interest to stop.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
25

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • New Jersey
      • Basking Ridge, New Jersey, United States, 07920
        • Recruiting
        • Memorial Sloan Kettering at Basking Ridge (Limited Protocol Activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
      • Middletown, New Jersey, United States, 07748
        • Recruiting
        • Memorial Sloan Kettering Monmouth (Limited protocol activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
      • Montvale, New Jersey, United States, 07645
        • Recruiting
        • Memorial Sloan Kettering Bergen (Limited protocol activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
    • New York
      • Commack, New York, United States, 11725
        • Recruiting
        • Memorial Sloan Kettering Suffolk - Commack (Limited Protocol Activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
      • Harrison, New York, United States, 10604
        • Recruiting
        • Memorial Sloan Kettering Westchester (All protocol activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
      • New York, New York, United States, 10065
        • Recruiting
        • Memorial Sloan Kettering Cancer Center (All Protocol Activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118
      • Rockville Centre, New York, United States, 11553
        • Recruiting
        • Memorial Sloan Kettering Nassau (Limited protocol activities)
        • Contact:
          • Paul Romesser, MD
          • Phone Number: 646-888-2118

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Subject or legally authorized representative is willing and able to provide written informed consent.

  • Age ≥ 18 on day of signing informed consent.

  • Consent for use of archival tissue and blood draws for research purposes.

  • Documentation of Disease

    o Patients must have pathologically confirmed anal squamous cell carcinoma.

    ° Pathology confirmation of the primary tumor at time of initial diagnosis is acceptable.

  • Disease Specific Criteria

    • Patients must have MRD after completion of definitive-CRT defined as:

      • Detectable on the last day of or after completing definitive-CRT.
      • In patients with MRD within 6 months of CRT completion, patients with no overt clinical or radiographic progression will be eligible, the treatment response evolves for up to 6-months after completion of CRT. The ACT II trial demonstrated that 70% of patients with an incomplete response to CRT at 3-months achieved a clinical complete response by 6-months [18].
      • ctDNA will be assessed using Natera Signatera, a CLIA- validated tumor informed ctDNA assay, which MSK patients currently undergo baseline, on-treatment, and surveillance monitoring as standard of care.
      • As patients will not have measurable radiographic disease at time of enrollment, RECIST will not be used for study.

    • Patients must sign informed consent within 4 weeks of positive ctDNA result. The 4 weeks is considered from the date that the ctDNA resulted, and not the date it is drawn.

  • Patients must have completed definitive CRT per institutional standards or as determined appropriate by the principal investigator.

  • Resolution of all non-hematologic toxicities of prior therapy or surgical procedures to baseline or Grade 1 (except for hypothyroidism requiring medication, which must have resolved to Grade ≤2), alopecia, and other toxicities considered clinically nonsignificant and/or stable on supportive therapy as determined by the investigator.

    o Lymphopenia is a known side effect of CRT, which can take months to resolve [4], and is not an exclusion to eligibility.

  • ECOG Performance Status of ≤ 2

  • Required Organ Function

    • Adequate hematologic function defined as follows:

      • Absolute neutrophil count (ANC) ≥= 1,000 cells/mm3
      • Platelets ≥ 75,000 cells/mm3
      • Hemoglobin ≥ 9 g/dl

    • Adequate renal function defined as follows:

      • Creatinine clearance (CrCL) of ≥30 mL/min by the Cockcroft-Gault formula (Note: For agents for which renal excretion is not a major route of clearance and for which renal toxicity is not an issue, the threshold for creatinine clearance should be ≥30 mL/min.):

CrCl (mL/min) = [ (140 - Age) × Weight (kg)] / [72 × Serum Creatinine (mg/dL)], multiplied by 0.85 for females.

  • Adequate hepatic function defined as follows:

    • Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN) (patients with known Gilbert's disease who have bilirubin level ≤ 3 x ULN may be enrolled)
    • AST and ALT ≤2.5 x institutional ULN

  • Adequate cardiac function defined as follows:

    • Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification.
    • To be eligible for this trial, patients with known congestive heart failure should be class 2B or better (see Appendix II: New York Heart Association (NYHA) Functional Classification).

Exclusion Criteria:

  • Presence of metastatic or recurrent disease.

  • Active infection requiring parenteral antibiotic(s).

  • Known active TB (Bacillus tuberculosis) infection.

  • Known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.

  • Active immune disease requiring systemic immunosuppression in excess of physiologic maintenance doses of corticosteroids (>10mg of prednisone or equivalent).

  • Interstitial lung disease or active noninfectious pneumonitis.

  • Known active CNS metastases and/or carcinomatous meningitis.

  • History of allogeneic bone marrow/stem, cell, or solid organ transplant.

  • Pregnant or nursing or expecting to conceive or father children within the projected duration of the trial.

    o Participants of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) during study therapy and for 6 months following the completion of study therapy.

  • Uncontrolled infection with human immunodeficiency virus (HIV). HIV-infected patients on effective anti-retroviral therapy with undetectable viral load and CD4+ count >300/μL within 6 months are eligible.

  • Known to be hepatitis B virus (HBV) surface antigen, or any other positive test for HBV indicating acute or chronic infection. Patients who are receiving or who have received anti-HBV therapy and have undetectable HBV DNA prior to study entry are eligible.

  • Known active hepatitis C virus (HCV) as determined by positive serology and confirmed by polymerase chain reaction (PCR). Patients on or who have received antiretroviral therapy are eligible provided they are virus-free by PCR for at least 6 months prior to study entry.

  • Receipt of a live vaccine within 28 days of planned start of study drug. Note: Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, chicken pox/zoster, yellow fever, rabies, 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.

  • Prior therapy with an anti-PD-1, anti-PD-L1, or anti-CTLA-4 agent.

  • History of allergic reaction to the study agent(s), compounds of similar chemical or biologic composition to the study agent (s) (or any of its excipients).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Anal squamous cell carcinoma

Participants have pathologically confirmed anal squamous cell carcinoma
Drug: Retifanlimab

IV Retifanlimab every 4 weeks for 6 cycles

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Rate of ctDNA clearance at 12 weeks
Time Frame: 12 weeks

To determine the rate of ctDNA clearance at 12-weeks (pre-Cycle 4) in ASCC participants with MRD after completion of definitive-intent chemoradiation, following treatment with retifanlimab.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Memorial Sloan Kettering Cancer Center

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Paul Romesser, MD, Memorial Sloan Kettering Cancer Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 4, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 4, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 4, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 4, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 10, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 26-298

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made following one year after publication and for up to 36 months later. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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