Nivolumab and Radiation Therapy or Ipilimumab as Adjuvant Therapy in Treating Patients With Merkel Cell Cancer

This phase I trial studies the side effects and how well nivolumab works when given together with radiation therapy or ipilimumab as adjuvant therapy in treating patients with Merkel cell cancer. Immunotherapy with monoclonal antibodies, such as nivolumab and ipilimumab, may help the body?s immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Radiation therapy uses high energy x-rays, gamma rays, neutrons, protons or other sources to kill tumor cells and shrink tumors. Giving nivolumab with radiation therapy or ipilimumab after surgery may kill any remaining tumor cells.

PRIMARY OBJECTIVES: I. To assess the tolerability of two different experimental immunotherapy regimens in the adjuvant setting in patients with Merkel cell carcinoma (MCC). SECONDARY OBJECTIVES: I. To assess the safety and tolerability profile of each of the treatment using Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. II. To assess the efficacy of each of the treatment arms according to recurrence-free survival (RFS) at one and half years, defined as the time between the date of randomization and the date of first progression (local, regional or distant metastasis) or death (whatever the cause), whichever occurs first. III. To assess the efficacy of each of the treatment arms according to overall survival (OS) at three years, defined from the time of randomization and the date of death, compared to historical registry control. EXPLORATORY OBJECTIVES: I. To explore potential biomarkers, next generation T cell receptor (TCR) sequencing will be performed to identify and longitudinally track individual T cell clones thus granting a comprehensive insight into immunological changes that occur within the tumor and peripheral blood throughout the course of the disease. OUTLINE: Patients are randomized to 1 of 2 arms. ARM A: Patients receive nivolumab intravenously (IV) over 30 minutes at week 0. Treatments repeat every 4 weeks for 1 year in the absence of disease progression or unacceptable toxicity. Beginning week 2, patients also receive radiation therapy on Monday-Friday or 5 days per week for 6 weeks in the absence of disease progression or unacceptable toxicity. ARM B: Patients receive nivolumab IV over 30 minutes and ipilimumab IV over 30 minutes at week 0. Treatments repeat every 2 weeks for nivolumab and 6 weeks for ipilimumab for up to 1 year in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 2 years and then every 6 months for 1 year.