Pembrolizumab treatment significantly improved progression-free survival versus brentuximab vedotin in a randomized, phase 3 trial including patients with relapsed or refractory classical Hodgkin lymphoma, an investigator has reported.
Median progression-free survival (PFS) was 13.2 versus 8.3 months in favor of pembrolizumab, according to the report on the KEYNOTE-204 trial, which included patients with classical Hodgkin lymphoma who either had relapsed after autologous stem cell transplant (SCT) or were ineligible for autologous SCT.
of Princess Margaret Cancer Centre in Toronto.
“This PFS benefit extended to key subgroups, including those ineligible for autologous transplant, patients with primary refractory disease, and patients who were brentuximab-vedotin naive,” Dr. Kuruvilla added in his presentation, which was part of the American Society of Clinical Oncology virtual scientific program.
Pneumonitis was more frequent in the pembrolizumab arm, but “appeared in general to be quite well managed” among patients who experienced this adverse event, according to Dr. Kuruvilla, who said that treatment with the programmed death–1 inhibitor should be considered “the preferred treatment option and the new standard of care” for patients with relapsed/refractory classic Hodgkin lymphoma who have relapsed after autologous SCT or are ineligible for it.
Although the pneumonitis findings are important to keep in mind, results of KEYNOTE-204 are indeed “practice defining” and immediately impactful, said Mark J. Roschewski, MD, clinical investigator in the lymphoid malignancies branch at the Center for Cancer Research, part of the National Cancer Institute, Bethesda, Md.
“I would select pembrolizumab over brentuximab for this patient population, particularly those that are refractory to chemotherapy,” he said in a commentary on the study also included in the virtual ASCO proceedings.
“There may be specific patient populations that I’d reconsider, such as those that might be at high risk for lung toxicity,” he added. “They may not be suitable for this, but it’s something to at least to be aware of.”
Although the antibody-drug conjugate brentuximab vedotin has been considered the standard of care for patients with relapse after autologous SCT, there has historically been no standard of care for patients who are ineligible for transplant because of chemorefractory disease, advanced age, or comorbidities, Dr. Kuruvilla said in his presentation.
In the KEYNOTE-204 study, 304 patients with relapsed/refractory classic Hodgkin lymphoma were randomized to receive either pembrolizumab 200 mg or brentuximab at 1.8 mg/kg intravenously every 3 weeks for up to 35 cycles.
The median age of patients was 36 years in the pembrolizumab arm and 35 years in the brentuximab vedotin arm, according to the report. Approximately 37% of the patients had previously undergone autologous SCT. About 40% had been refractory to frontline therapy, while 28% relapsed within 12 months of therapy and 32% relapsed later than 12 months.
Median PFS by blinded independent central review was 13.2 versus 8.3 months in the pembrolizumab and brentuximab arms, respectively (hazard ratio, 0.65; 95% confidence interval, 0.48-0.88; P = .00271), Dr. Kuruvilla reported.
The benefit extended to “key subgroups” in the trial, he added, including those who were ineligible for autologous SCT, those with primary refractory disease, and those who were naive to brentuximab vedotin, with HRs of 0.61, 0.52, and 0.67, respectively.
Pembrolizumab was also associated with more durable responses versus brentuximab vedotin, according to the investigator.
The overall response rate was 65.6% and 54.2%, respectively, for pembrolizumab and brentuximab, although this difference of approximately 11 percentage points did not meet criteria for statistical significance, he said. Duration of response was 20.7 months or pembrolizumab and 13.8 months for brentuximab.
The rate of serious treatment-related adverse events was similar between groups, according to Dr. Kuruvilla, who reported grade 3-5 events occurring in 19.6% and 25.0% of the pembrolizumab and brentuximab arms. Serious treatment-related adverse events were numerically more frequent in the pembrolizumab arm (16.2% vs. 10.5%) and there was one treatment-related death caused by pneumonia, seen in the pembrolizumab arm.
Pneumonitis occurred in 2.6% of the brentuximab-treated patients and in 10.8% of pembrolizumab-treated patients, of which half of cases were grade 3-4, according to the report.
In the pembrolizumab arm, pneumonitis was felt to be drug-related in 15 of 16 cases, according to Dr. Kuruvilla, who added that 15 of 16 patients required corticosteroid therapy. “This has led to the resolution of the pneumonitis in 12 of 16 patients, with ongoing resolution in one further patient.”
Research funding for KEYNOTE-204 came from Merck Sharp & Dohme. Dr. Kuruvilla provided disclosures related to Merck and a variety of other pharmaceutical companies. Dr. Roschewski said he had no relationships to disclose.
SOURCE: Kuruvilla J et al. ASCO 2020, Abstract 8005.