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| 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.
