Pembrolizumab Added to Chemo Maintains OS, PFS Benefits in Metastatic NSCLC


Yasir Y. Elamin, MD, University of Texas MD Anderson Cancer Center, Houston, discusses the clinical significance of the KEYNOTE‑189 clinical trial evaluating the use of chemotherapy plus pembrolizumab in patients with metastatic, nonsquamous non–small-cell lung cancer (NSCLC).


I would like to finish up by switching gears a little bit and talk about the outcomes of KEYNOTE‑189. As you recall, this is a randomized phase 3 trial, which has compared the addition of pembrolizumab.

We had 2 arms, an arm of standard of care at the time, which is chemotherapy, carboplatin, and pemetrexed. We are comparing it with the same regimen with the addition of pembrolizumab.

The trial has been reported in the past. It was positive for OS end point and the PFS end point, as well. Here are reported the updated OS benefit, and they're showing us that the median overall survival in the pembrolizumab group was 22 months, compared to approximately 11 months in the control arm, carboplatin and pemetrexed.

Interestingly, it will also show that the benefit of the additional pembrolizumab is universal across all subgroups if we use PD‑L1 to stratify patients.

In patients who are higher expressors of PD‑L1, meaning that they had PD‑L1 expression more than 50%, the median OS was approximately 28 months, compared to 10 months in the control group.

If you take patients who are low expressors of PD‑L1, so those who express PD‑L1 between 1% to 49%, the median OS with pembrolizumab was 22 months, compared to 12 months in the control group.

In those who did not express PD‑L1, the median OS for pembro plus chemo was 17 months, compared to 10 months with the standard of care group. Taken together, pembrolizumab combined with chemotherapy is certainly superior to chemotherapy alone in terms of overall survival, irrespective of the PD‑L1 expression.

It remains a valid and important first‑line option for these patients who have adenocarcinoma, metastatic disease, and do not express EGFR or ALK alteration.

I think, again, this is an important milestone in the way that we treat those patients. Thank you.

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