# KEYNOTE-170: pembrolizumab in relapsed or refractory primary mediastinal large B-cell lymphoma

Source: https://onco.cc/key-papers/paper-keynote-170-pembrolizumab-pmbcl-armand-jco-2019/  
OnCo record `paper-keynote-170-pembrolizumab-pmbcl-armand-jco-2019` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Pembrolizumab produced responses in about 45 percent of patients with primary mediastinal B-cell lymphoma that had relapsed after chemotherapy, a lymphoma whose frequent 9p24.1 amplification makes it unusually sensitive to PD-1 blockade.

## Summary

Phase 2 study of 53 patients with relapsed or refractory primary mediastinal large B-cell lymphoma treated with pembrolizumab, supported by a phase 1b cohort of 21 patients.

Objective response was 45 percent with complete responses in 13 percent, median duration of response not reached after a median follow-up of 12.5 months, and no deaths from treatment-related events; 9p24.1 alterations were near-universal.

## Fields

- Kind: Key paper
- Last checked: 2026-09-17
- Journal: Journal of Clinical Oncology
- Year: 2019
- DOI: 10.1200/JCO.19.01389
- Authors: Armand P, Rodig S, Melnichenko V, et al.
- Findings: Objective response 45 percent; complete response 13 percent.; Median duration of response not reached at 12.5 months.
- What it means: Pembrolizumab is approved for relapsed primary mediastinal B-cell lymphoma and is the usual bridge to CAR-T or transplant in chemotherapy-refractory patients.
- Caveats: Single-arm; small numbers.; Most responders eventually need consolidative therapy.

## Sources

- J Clin Oncol 2019: https://doi.org/10.1200/JCO.19.01389
- PubMed: https://pubmed.ncbi.nlm.nih.gov/31609651/

## Connected records

- cancers: [Primary mediastinal (thymic) large B-cell lymphoma](https://onco.cc/cancers/primary-mediastinal-b-cell-lymphoma/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- trials: [KEYNOTE-170](https://onco.cc/trials/keynote-170/)
- journals: [Journal of Clinical Oncology](https://onco.cc/journals/jco/)

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