Study of Pembrolizumab (MK-3475) in Participants With Relapsed or Refractory Classical Hodgkin Lymphoma (MK-3475-087/KEYNOTE-087)

Inclusion criteria:

* Relapsed or refractory de novo classical Hodgkin lymphoma
* Participant may have failed to achieve a response to, progressed after, or be ineligible for autologous stem cell transplant (auto-SCT)
* Participant may have failed to achieve a response or progressed after treatment with brentuximab vedotin or may be brentuximab vedotin naïve
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
* Measurable disease
* Adequate organ function

Exclusion criteria:

* Diagnosis of immunosuppression or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication
* Prior monoclonal antibody within 4 weeks prior to study Day 1 or chemotherapy, targeted small molecular therapy, or radiation therapy within 2 weeks prior to study Day 1
* Prior allogeneic hematopoietic stem cell transplantation
* Known clinically active central nervous system involvement
* Known additional malignancy that is progressing or requires active treatment
* Has a known history of Human Immunodeficiency Virus (HIV)
* Has known active Hepatitis B (HBV) or Hepatitis C (HCV)
* Active autoimmune disease requiring systemic treatment in past 2 years
* Has a history of (non-infectious) pneumonitis that required steroids, or current pneumonitis