Merck & Co. recently announced the US Food and Drug Administration has granted Keytruda (pembrolizumab) accelerated approval as a treatment for patients with advanced (metastatic) non-small cell lung cancer (NSCLC) who have not responded to traditional treatments and have tumors that bear the protein PD-L1. The drug is currently approved upon undergoing a companion diagnostic test, the PD-L1 IHC 22C3 pharmDx test.
Today, lung cancer ranks as the top cause of death in the United States, with the National Cancer Institute projecting approximately 221,200 new diagnoses and 158,040 deaths in 2015. “Our growing understanding of underlying molecular pathways and how our immune system interacts with cancer is leading to important advances in medicine,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Today’s approval of Keytruda gives physicians the ability to target specific patients who may be most likely to benefit from this drug.”
By blocking the PD-1/PD-L1 cellular pathway, Keytruda is able to give the body’s immune system a boost in recognizing and destroying cancer cells. This is not the first time Keytruda receives approval, since it was approved in 2014 as a treatment for advanced melanoma in patients who had initially been treated with ipilimumab.
Keytruda’s safety profile was observed in 550 patients diagnosed with advanced NSCLC, with scientists observing only the following common side effects: fatigue, decreased appetite, shortness of breath or impaired breathing (dyspnea) and cough. As for its efficacy profile, Keytruda was tested on a subgroup of 61 patients with advanced NSCLC that had progressed from receiving platinum-based chemotherapy or targeted therapy for specific genetic mutations (ALK or EGFR). The results demonstrated that Keytruda was able to induce tumor shrinkage in 41 percent of patients, with the effect lasting between 2.1 and 9.1 months.
The FDA granted Keytruda breakthrough therapy designation since Merck clinically proved the drug could offer a substantial improvement over available therapies. Moreover, it also received a priority review status, which is granted to novel therapies that have the potential to be a significant improvement in safety or effectiveness in the treatment of a serious disease.
The FDA’s accelerated approval program allows the approval of a drug to treat a serious or life-threatening conditions based on clinical data that shows the drug “has an effect on a surrogate endpoint reasonably likely to predict clinical benefit to patients”. This program allows for earlier patient access to promising new drugs during the time the company develops their confirmatory clinical studies.