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Lung CancerMay 2018Summary reviewed May 2026

What the KEYNOTE-189 Trial Found — Pembrolizumab Plus Chemotherapy for Lung Cancer

KEYNOTE-189 tested pembrolizumab, an immunotherapy that releases brakes on the immune system, added to standard chemotherapy as the first treatment for 616 people with metastatic non-squamous non-small cell lung cancer without targetable mutations.

What the trial was testing

The KEYNOTE-189 enrolled 616 patients with lung cancer. The study was sponsored by Merck and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

51% lower risk of death when pembrolizumab was added to chemotherapy.

New England Journal of Medicine · 2018 · NCT02578680

These findings — that of death when pembrolizumab was added to chemotherapy as a first-line lung cancer treatment — were published in the New England Journal of Medicine and represent the headline result of the study.

Researchers tracked outcomes across 616 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with lung cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Pembrolizumab (Keytruda) plus chemotherapy is FDA-approved as a first-line treatment for metastatic non-squamous non-small cell lung cancer without targetable mutations and available now. It is given as IV infusions. Immune-related side effects can affect any organ and need close monitoring. Ask your oncologist whether immunotherapy fits your case.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.