SAN FRANCISCO—Patients with classical Hodgkin lymphoma (cHL) who were heavily pretreated—including those who had failed brentuximab vedotin—had clinical benefit from pembrolizumab (MK-3475), according to preliminary results from a open-label phase 1b study (Abstract 290) reported at the 56th American Society of Hematology (ASH) Annual Meeting and Exposition.
In 29 of the 31 patients in the KEYNOTE-013 study evaluable for response, the clinical benefit rate was 86%, and the overall response rate was 66%, which included 6 (21%) complete remissions, said Craig H. Moskowitz, MD, of the Department of Medicine, Memorial Sloan Kettering Cancer Center in New York, NY. In addition, pembrolizumab, which blocks the programmed death-1 (PD-1) pathway, was well tolerated.
These results “support the continued development of pembrolizumab in patients with Hodgkin lymphoma,” Dr. Moskowitz said. Among the enrolled patients, PD-L1 expression was observed in 100% of the evaluable samples.
Median age of the patients was 32 years (range, 20-67 years); 52% of patients had received 5 or more prior therapies for advanced disease. In addition to failing brentuximab vedotin, 69% of patients had also failed autologous stem cell transplantation.
At the analysis cut-off date of November 17, 2014, median time to response was 12 weeks; 17 of 19 (89%) of patients had responses that were ongoing. Median duration of response was not reached (range, 1+ to 185+ days). At a median duration of follow-up of 153 days (range, 1-341), 9 patients had discontinued therapy, 1 due to an adverse event, 7 due to disease progression, and 1 due to a complete response. Twenty patients remained on therapy and 1 patient went on to transplant.
Three patients (10%) experienced a total of 4 adverse events that were grade 3; no grade 4 treatment-related AEs or treatment-related deaths were observed. The grade 3 adverse events (AEs) were one occurrence each of axillary pain, hypoxia, joint swelling, and pneumonitis.
The AEs of clinical interest included hyperthyroidism (grade 1-2 in 2 patients), hypothyroidism (grade 1-2 in 3 patients), pneumonitis (grade 1-2 in 2 patients and grade 3 in 1 patient), and colitis in 2 patients (grade 3 in 1 patient and not reported in 1 patient).
“It will be important to further evaluate this drug in combination with others, or perhaps even as a maintenance treatment, to enhance the post-transplant immune response,” Dr. Moskowitz said in a press release.