An early stage clinical trial of a combination of cancer medicines from Merck & Co. Inc. and Incyte Corp. produced a 35% overall response rate among 40 patients with advanced non-small cell lung cancer.
The data are a strong basis for continuing development of the combination as an initial therapy against lung cancer, the companies said in a release issued June 3 during the annual meeting of the American Society of Clinical Oncology in Chicago.
Two of the patients whose cancer responded to the therapy, consisting of Merck's U.S.-approved Keytruda and Incyte's experimental epacadostat, saw their tumors disappear, while 12 patients saw their tumors shrink. In addition, 10 of the 14 responses to the treatment are continuing, with some continuing after more than 76 weeks, the companies said.
Five percent of patients experienced treatment-related side effects that led to discontinuation of treatment.
Patients with both higher and lower levels of the biomarker PD-L1 demonstrated responses to the combination therapy.
Both Keytruda and epacadostat harness the body's natural immune response by inhibiting molecules that typically restrain the immune system. Keytruda inhibits the PD-1 protein, while epacadostat inhibits the immunosuppressive enzyme indoleamine 2,3-dioxygenase 1, or IDO1.
Keytruda is already approved to treat non-small cell lung cancer. But Food and Drug Administration approval of the combination therapy would be Keytruda's first approval against the disease in combination with another immunotherapy.
Analysts expect sales of the drug to more than double in 2017 to exceed $3 billion.