Expanding a drug's market base is one surefire way to boost its sales, and that is what Merck is doing for its immuno-oncology blockbuster drug Keytruda. On March 15, 2017, the FDA will announce its decision of whether or not to approve Keytruda for the treatment of patients with refractory classical Hodgkin lymphoma (cHL) or for patients who have relapsed after three or more prior lines of therapy.Keytruda has already received FDA approval for the treatment of metastatic melanoma, metastatic non-small cell lung cancer, and recurrent or metastatic head and neck squamous cell carcinoma.The drug brought home sales of $1.40 billion in 2016, up 148% compared to 2015.