FDA approved Merck’s anti-PD1

Yesterday the FDA approved Merck’s anti-PD1 drug for use in metastatic melanoma. This drug has the best response rate of any drug approved for melanoma, and everyone expects big changes because of this approval. Keytruda is only approved for patients who have progressed on ipi and, if applicable, on a BRAF inhibitor. I am quite sure it will be widely prescribed off label beyond those parameters. The drug is given by infusion every 3 weeks, at a cost of $12,500/month. The median response time in the data used for this approval is 6.2 months, though many responded much longer.