First immunotherapy approved for colorectal ca patients with MSI-H or dMMR tumors

WASHINGTON — The FDA approved IV pembrolizumab (Keytruda) as a first-line treatment for patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer.

Pembrolizumab, which was previously approved to treat a number of cancers, including melanoma, non-small cell lung cancer, and renal cell carcinoma, is the first approved immunotherapy for patients who have MSI-H or dMMR tumors — approximately 5% of patients with colorectal cancer — as a first-line treatment option without chemotherapy.

This new indication received Priority Review and Real-Time Oncology Review designations, and it was reviewed in cooperation with the FDA’s international agency counterparts via Project Orbis.

“Metastatic colorectal cancer is a serious and life-threatening disease with a poor prognosis. Available current therapy with chemotherapy combinations and other biologics are associated with substantial toxicity,” said Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research, in a statement. “Having a non-chemotherapy option available for selected patients is a noteworthy paradigm shift in treatment.”

This new indication for pembrolizumab is based on the results of a multicenter, international, open-label, active-controlled, randomized trial pitting pembrolizumab against chemotherapy in a cohort of 307 patients with MSI-H or dMMR metastatic colorectal cancer.

“The study demonstrated a statistically significant improvement in progression-free survival (PFS) as assessed by blinded independent review,” the FDA explained. “Median PFS was 16.5 months in the [pembrolizumab] group and 8.2 months in the standard of care group. Longer-term analysis is needed to assess for an effect on survival.”

The most common side-effects associated with pembrolizumab include fatigue, musculoskeletal pain, decreased appetite, pruritis, diarrhea, nausea, rash, fever, cough, dyspnea, constipation, pain, and abdominal pain. The agency added that pembrolizumab can cause immune-mediated side effects, including pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis. Patients who experience severe or life-threatening infusion-related reactions should immediately stop taking the drug, the FDA warned, and women who are pregnant or breastfeeding should not take pembrolizumab.

Pembrolizumab is manufactured by Merck & Co.

John McKenna, Associate Editor, BreakingMED™

Cat ID: 23

Topic ID: 78,23,730,16,23,192