# KEYNOTE-170

Source: https://onco.cc/trials/keynote-170/  
OnCo record `keynote-170` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

KEYNOTE-170 showed that a PD-1 antibody works in primary mediastinal B-cell lymphoma, whose cells carry extra copies of the PD-L1 gene: almost half of heavily treated patients responded, which led to the first drug approval specific to this lymphoma.

## Summary

KEYNOTE-170 treated 53 patients with relapsed or refractory primary mediastinal large B-cell lymphoma with pembrolizumab 200 mg every three weeks for up to two years. The disease is defined by gains and rearrangements of the 9p24.1 locus that carries PD-L1, PD-L2 and JAK2, the same lesion that makes classical Hodgkin lymphoma so sensitive to PD-1 blockade.

The objective response rate was 45 percent with 13 percent complete responses, and responses were durable, with the median duration not reached at a median follow-up of over a year. Together with the KEYNOTE-013 cohort this supported FDA accelerated approval in June 2018 for patients who had relapsed after two or more lines, the first approval of any drug specifically for this lymphoma.

CheckMate 436 later combined nivolumab with brentuximab vedotin in the same setting with a higher response rate, and CD19 CAR-T products licensed for large B-cell lymphoma include primary mediastinal disease in their labels.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-17
- Registry id: NCT02576990
- Phase: 2
- Setting: Relapsed or refractory primary mediastinal large B-cell lymphoma after autologous transplant, or ineligible for it after two or more lines: pembrolizumab monotherapy
- Sponsor: Merck
- Enrolled: 53
- Result: Objective response rate 45%, complete response 13%, in 53 patients with relapsed or refractory disease; FDA accelerated approval June 2018.
- Outcomes: Objective response rate: Pembrolizumab 45%; Complete response rate: Pembrolizumab 13%
- Replication: KEYNOTE-013 (21 patients) showed the same response rate; CheckMate 436 (nivolumab plus brentuximab vedotin) reported a 73 percent response rate in the same population.

## Sources

- ClinicalTrials.gov NCT02576990: https://clinicaltrials.gov/study/NCT02576990
- Journal of Clinical Oncology 2019: https://doi.org/10.1200/JCO.19.01389

## Connected records

- cancers: [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Primary mediastinal (thymic) large B-cell lymphoma](https://onco.cc/cancers/primary-mediastinal-b-cell-lymphoma/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- targets: [JAK2](https://onco.cc/targets/jak2/), [PD-1](https://onco.cc/targets/pd1/), [PD-L1](https://onco.cc/targets/pdl1/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- companies: [Merck & Co. (MSD)](https://onco.cc/companies/merck/)

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