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Study of Pembrolizumab (MK-3475) in Participants With Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma or Relapsed or Refractory Richter Syndrome (MK-3475-170 / KEYNOTE-170)

Trial Status: Complete

In this study, participants with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) or relapsed or refractory Richter Syndrome (rrRS) will receive pembrolizumab (MK-3475). The efficacy of pembrolizumab in the treatment of rrPMBCL and rrRS will be evaluated. The primary study hypothesis is that intravenous (IV) administration of single agent pembrolizumab to the rrPMBCL cohort will result in an Objective Response Rate (ORR) of greater than 15% using the International Working Group (IWG) response criteria (Cheson, 2007) by independent central review. Effective with Protocol Amendment 04, enrollment into the rrRS cohort was closed.

Inclusion Criteria

  • Primary mediastinal large B-cell lymphoma (PMBCL):
  • Diagnosis of relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) AND
  • Has relapsed after autologous stem cell transplant (auto-SCT) or has failed to achieve a Complete Response or Partial Response within 60 days of auto-SCT. Participants may have received intervening therapy after auto-SCT for relapsed or refractory disease, in which case they must have relapsed after or be refractory to their last treatment OR
  • For participants who are ineligible for auto-SCT, has received at least ≥2 lines of prior therapy and has failed to respond to or relapsed after their last line of treatment. For participants who received consolidative local radiotherapy after systemic therapy, local radiotherapy will not be considered as a separate line of treatment
  • Previously exposed to rituximab as part of prior lines of treatment
  • Richter syndrome (RS):
  • Pathologic diagnosis per local institutional review of RS that transformed from chronic lymphocytic leukemia (CLL)
  • Relapsed or refractory Richter syndrome and has received ≥1 previous treatment for RS
  • All Participants:
  • Radiographically measurable disease
  • Performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale
  • Life expectancy >3 months
  • Adequate organ function
  • Female participants of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 120 days after the last dose of study drug
  • Male participants of childbearing potential must agree to use an adequate method of contraception, starting with the first dose of study drug through 120 days after the last dose of study drug

Exclusion Criteria

  • Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 4 weeks of the first dose of study drug
  • Is receiving systemic steroid therapy <3 days before the first dose of study drug or receiving any other form of immunosuppressive medication
  • Prior monoclonal antibody within 4 weeks prior to study Day 1 (2 weeks for RS participants) or who has not recovered (i.e. ≤ Grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier (2 weeks for RS participants)
  • Prior chemotherapy or targeted small molecule therapy within 2 weeks prior to study Day 1 or prior radiation therapy within 4 weeks prior to study Day 1
  • Allogeneic hematopoietic stem cell transplantation within the last 5 years.
  • Has a known additional malignancy (except underlying CLL for RS) that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy
  • Known clinically active central nervous system involvement
  • Active autoimmune disease requiring systemic treatment in past 2 years
  • History of (non-infectious) pneumonitis that required steroids, or current pneumonitis
  • Active infection requiring intravenous systemic therapy
  • Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the study, starting with the pre-screening or screening visit through 120 days after the last dose of study drug
  • Has received prior therapy with an anti-programmed cell death 1 (anti-PD-1), anti-programmed cell death ligand 1 (anti-PD-L1), anti-programmed cell death ligand 2 (anti-PD-L2), anti-CD137, or anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) antibody (including ipilimumab or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways)
  • Known human immunodeficiency virus (HIV), or Hepatitis B or C
  • Has received a live vaccine within 30 days prior to first dose of study drug


City of Hope Comprehensive Cancer Center


Mayo Clinic in Florida


Brigham and Women's Hospital
Dana-Farber Cancer Institute


Ann Arbor
University of Michigan Comprehensive Cancer Center


Mayo Clinic in Rochester


Ohio State University Comprehensive Cancer Center


University of Pennsylvania / Abramson Cancer Center


UT Southwestern / Simmons Cancer Center-Dallas
Status: ACTIVE
Contact: Marcella West Aguilar
Phone: 214-648-1479
M D Anderson Cancer Center
Status: ACTIVE


Fred Hutch / University of Washington Cancer Consortium
Status: ACTIVE

Treatment with pembrolizumab will continue for a maximum of 35 administrations (approximately

2 years) or until documented disease progression by investigator assessment, unacceptable

adverse event(s) (AEs), intercurrent illness that prevents further administration of

treatment, participant withdraws consent, pregnancy of the participant, noncompliance with

study treatment or procedure requirements, or administrative reasons.

Trial Phase Phase II

Trial Type Treatment

Lead Organization
Merck and Company Inc

  • Primary ID 3475-170
  • Secondary IDs NCI-2016-00052, 2015-002406-37, KEYNOTE-170, MK-3475-170
  • ID NCT02576990