FDA approves first cancer treatment drug based on tumor biomarker, instead of tumor origin.

courtesy: Merck 

In an important announcement, The U.S. Food and Drug Administration (FDA) granted accelerated approval to Merck’s Keytruda (pembrolizumab) for treatment in patients whose cancers have a specific genetic feature (biomarker).

This is the first time the agency has approved a cancer treatment based on a common biomarker rather than the location in the body where the tumor originated.

Keytruda (pembrolizumab) is indicated for the treatment of adult and pediatric patients who have unresectable or metastatic solid tumors that have been identified as having a biomarker referred to as microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR).

Tumors with these biomarkers are most commonly found in colorectal, endometrial and gastrointestinal cancers, but also less commonly appear in cancers arising in the breast, prostate, bladder, thyroid gland and other places.

“This is an important first for the cancer community,” said Richard Pazdur, M.D., acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research and director of the FDA’s Oncology Center of Excellence. “Until now, the FDA has approved cancer treatments based on where in the body the cancer started—for example, lung or breast cancers. We have now approved a drug based on a tumor’s biomarker without regard to the tumor’s original location.”

Keytruda works by blocking the cellular pathway known as PD-1/PD-L1 (proteins found on the body’s immune cells and some cancer cells). Keytruda is currently used in patients with metastatic melanoma, metastatic non-small cell lung cancer, recurrent or metastatic head and neck cancer, refractory classical Hodgkin lymphoma, and urothelial carcinoma.

The FDA approval comes in wake of results of 5 clinical trial involving 149 patients with 15 different cancer types. The common cancers were endometrial, gastrointestinal and colorectal.

Nearly 40% of patients in this trial responded well to the treatment with 78% of those were symptom free for more than 6 months.

Common side effects of Keytruda include fatigue, itchy skin (pruritus), diarrhea, decreased appetite, rash, fever (pyrexia), cough, difficulty breathing (dyspnea), musculoskeletal pain, constipation and nausea.

 Keytruda can cause serious conditions known as immune-mediated side effects, including inflammation of healthy organs such as the lungs (pneumonitis), colon (colitis), liver (hepatitis), endocrine glands (endocrinopathies) and kidneys (nephritis).

The FDA press release can be accessed here.