FDA Approves Keytruda for Adult, Pediatric Patients with Lymphoma

The FDA this week approved pembrolizumab (Keytruda) for the treatment of both adults and children with refractory classical Hodgkin lymphoma (cHL), or those who relapsed after 3 or more prior treatments. This approval makes pembrolizumab the only approved anti-PD-L1 treatment for patients with difficult-to-treat cHL, regardless of prior stem cell transplantation or brentuximab vedotin use, according to a press release from Merck.

Under accelerated approval, the indication is based on tumor response rate and duration of response. Its approval status will be contingent on additional clinical trials that further demonstrate its clinical benefit.

The approval is based on positive results from the KEYNOTE-087 clinical trial, which included 210 patients with cHL. The investigators discovered that pembrolizumab demonstrated an overall response rate of 69%. The drug was also observed to have a complete remission rate of 22% and a partial remission rate of 47%.

Merck reported that the median duration of response was 11.1 months among 145 patients.

“The results from KEYNOTE-087 showed that most patients with relapsed or refractory classical Hodgkin lymphoma responded to treatment with Keytruda, and 22% experienced complete remission,” said Roger M. Perlmutter, MD, president, Merck Research Laboratories. “Today’s approval — the first for Keytruda in a hematologic malignancy – reinforces the hope that immunotherapy will prove useful in a wide variety of cancers.”

The FDA approved pembrolizumab in a dose of 200-mg for adults and 2-mg/kg for pediatric patients, and is administered every 3 weeks until progression, toxicity, or up to 24 months without progression.

Merck noted a limited experience of pediatric patients treated with pembrolizumab, and the recent approval in this population was extrapolated from the findings among adults.

In another study, 40 pediatric patients with advanced melanoma, PD-L1-positive solid tumors or lymphoma were treated with pembrolizumab. The safety profile of the drug in pediatric patients was observed to be similar to those seen among adults. However, pediatric patients were more likely to experience fatigue, vomiting, abdominal pain, hypertransaminasemia, and hyponatremia.

In the KEYNOTE trial, the most common adverse events among adults included fatigue, pyrexia, cough, musculoskeletal pain, diarrhea, and rash, according to the release.

Common immune-mediated adverse events associated with pembrolizumab include pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis. Other immune-mediated complications, including death, have occurred in patients with cHL who received a hematopoietic stem cell transplantation after treatment with pembrolizumab, according to the release.

Currently, pembrolizumab has been approved to treat patients with melanoma, lung cancer, head and neck cancer, and classical Hodgkin lymphoma.

“For the patients with classical Hodgkin lymphoma who are not cured with existing treatments, there are limited options, and treating their disease becomes more challenging,” said Craig Moskowitz, MD, clinical director, division of hematologic oncology, Memorial Sloan Kettering Cancer Center. “This approval is an important step forward in treating these patients, who are generally young and have a particularly poor prognosis, and gives us the opportunity to help patients in their fight against this devastating disease.”