On October 14, 2020, the FDA expanded the approval of pembrolizumab (Keytruda; Merck), a PD-1 inhibitor, for the treatment of relapsed or refractory classical Hodgkin lymphoma in adults and for refractory classical Hodgkin lymphoma or classical Hodgkin lymphoma in pediatric patients that has relapsed after receiving ≥2 lines of therapy. The FDA granted pembrolizumab orphan drug and breakthrough therapy designations for this indication.
This approval was based on the results of the KEYNOTE-204 study, a phase 3, randomized, open-label clinical trial of 304 adults with relapsed or refractory classical Hodgkin lymphoma. The patients were randomized in a 1:1 ratio to pembrolizumab 200 mg every 3 weeks or to brentuximab vedotin (Adcetris) 1.8 mg/kg every 3 weeks for up to 2 years.
The efficacy of pembrolizumab in adults and pediatric patients with relapsed or refractory classical Hodgkin lymphoma was based on progression-free survival (PFS). The PFS was significantly longer in the pembrolizumab arm versus the brentuximab vedotin arm. The median PFS was 13.2 months in the pembrolizumab arm and 8.3 months in the brentuximab vedotin arm (hazard ratio, 0.65; 95% confidence interval, 0.48-0.88; P = .0027).
Serious adverse reactions occurred in 30% of the patients who received pembrolizumab.