[Pembrolizumab treatment of prostate cancer].

In this case report, a 73-year-old male with metastatic prostate cancer is presented. After progression on available standard treatments, he was enrolled in a precision medicine program. Re-biopsy revealed a defect in mismatch repair and an Activin A receptor type 2A mutation associated with high microsatellite instability. Pembrolizumab was started with clinical response, tumor regression, PSA-decline, and no adverse reactions. After 5 months, the treatment is ongoing. This illustrates that pembrolizumab can have an effect in some patients with prostate cancer and underscores the importance of molecular diagnostics.