Ipilimumab With or Without Nivolumab in Relapsed/Refractory cHL

This is an open-label, multi-center, phase II study of ipilimumab with or without nivolumab for patients with relapsed or refractory (R/R) classic Hodgkin lymphoma (cHL). Nivolumab is a drug which is approved by the United States Food and Drug Administration (FDA) for the treatment of adult patients experiencing relapsed Hodgkin lymphoma (cHL) who have received at least two prior systemic therapies. Ipilimumab has been approved by the FDA for the treatment of metastatic melanoma (a type of skin cancer), and specific types of previously treated advanced kidney cancers. The study drugs have not been approved in combination for cHL by the Food and Drug Administration (FDA). This study is for participants who previously had progressive disease when receiving a PD-1 mAb. Participants will receive 4 cycles of ipilimumab monotherapy and then undergo restaging imaging. Patients who achieved an objective response will continue treatment with ipilimumab maintenance. Other patients will receive 4 cycles of nivolumab and ipilimumab followed by ipilimumab maintenance treatment. Patients who have progressive disease after fewer than 4 cycles of ipilimumab are eligible to proceed to combination therapy with nivolumab and ipilimumab if they are clinically stable. Participants will receive up to \~ 24 months of study treatment. After completion of therapy, participants will be followed every 3 months for 2 years and then every 6 months for the next 5 years. It is expected that about 13 people will participate in this research study. Bristol Myers Squibb (BMS) is supporting this research study by providing the study drugs and funding for the study.