The drug received the sanction from the Food and Drug Administration in October for the treatment of a particular set of patients with a genetic mutation, who suffer from advanced non-small cell lung cancer (NSCLC). The drug aims at a protein, which is articulated by immune cells, that is attacked by cancer cells. The immune system becomes stronger in terms of attacking tumor cells by aiming at the protein.

“By continuing to refine and expand our selection of patients who stand to benefit from this type of therapy, we are profoundly changing the way that patients with this common cancer are treated”, said Dr. Edward Garon, a researcher at UCLA.

The study involved examination of 1,034 patients from 2013 to 2015. The patients were randomly given one of two dosage sizes of pembrolizumab or the chemotherapy drug docetaxel. No major difference was detected in the survival rate of patients taking the docetaxel and a low dose of pembrolizumab. However, increased dose of pembrolizumab proved to be highly effective compared to chemotherapy.

The immunotherapy drug has been proved to decrease the death risk by 30% and extend the life of patients by a minimum of 13 months, according to Merck’s CEO, Kenneth Frazier.