FDA approves Keytruda

The FDA approved pembrolizumab monotherapy for patients with metastatic small cell lung cancer that progressed on or after platinum-based chemotherapy and at least one other prior line of therapy.

This marks the first approval of pembrolizumab (Keytruda, Merck), an anti-PD-1 therapy, for small cell lung cancer.

“Keytruda is already an established treatment option for non-small cell lung cancer, and [this] approval in small cell lung cancer demonstrates our commitment to bringing forward new treatment options for patients with advanced, difficult-to-treat cancers,” Jonathan Cheng, MD, vice president of oncology clinical research at Merck Research Laboratories, said in a press release. “We look forward to continuing to advance important clinical research in small cell lung cancer.”

The FDA granted pembrolizumab accelerated approval for this indication based on tumor response rate and durability of response observed in the KEYNOTE-158 and KEYNOTE-028 trials.

Those trials included 83 patients with small cell lung cancer and disease progression on or after platinum-based chemotherapy and at least one other prior line of therapy. Among them, 64% had received two prior lines of therapy and 36% had received three or more lines of therapy. Sixty percent of patients previously received thoracic radiotherapy and 51% had received radiotherapy to the brain.

Patients received 200 mg IV pembrolizumab every 3 weeks (n = 64) or 10 mg/kg IV every 2 weeks (n = 19) until documented disease progression, unacceptable toxicity or for a maximum of 24 months.

Objective response rate and duration of response served as the major efficacy outcome measures.

As  HemOnc Today previously reported, results showed an ORR of 19% (95% CI, 11-29), which included a 2% complete response rate and 17% partial response rate.

Responses ranged from 4.1 to 35.8+ months, with 94% of the 16 responding patients experiencing a duration of response of 6 months or longer. For 56% of patients, response exceeded 18 months.

Researchers reported that the adverse event profile appeared similar to that observed in other solid tumor types.

“Small cell lung cancer, which accounts for 10% to 15% of all lung cancers, is often diagnosed at an advanced stage where the prognosis is very poor and there have historically been limited treatment options,” Patrick Ott, MD, PhD, clinical director of the Center for Immuno-Oncology at Dana-Farber Cancer Institute, said in the press release. “The approval of Keytruda in small cell lung cancer provides an additional treatment option for patients based on the clinical response rates from KEYNOTE-158 and KEYNOTE-028.”