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MelanomaJuly 2016Summary reviewed July 2026

An Immunotherapy Pill Shrank Brain Tumors in 1 of 3 Skin Cancer Patients

This study tested pembrolizumab (Keytruda) in patients with melanoma or lung cancer that had spread to the brain. About one in four to one in three patients saw their brain tumors shrink, and most responses lasted through the study period.

What the trial was testing

The trial enrolled 65 patients with melanoma. The study was sponsored by Yale University and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was initial testing (phase 2). 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

22% of melanoma patients and 33% of lung cancer patients saw brain tumors shrink.

The Lancet. Oncology · 2016 · NCT02085070

These findings — that saw their brain tumors shrink with pembrolizumab treatment — were published in the The Lancet. Oncology and represent the headline result of the study.

Researchers tracked outcomes across 65 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 melanoma, 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

This was an initial testing study. Pembrolizumab is now FDA-approved for melanoma and certain lung cancers, including some cases with brain metastases. If you have cancer that has spread to your brain, ask your oncologist whether pembrolizumab or similar immunotherapy might be an option for you.

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.