Patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) whose disease progressed following a prior complete response — meaning no traces of disease were found following treatment — saw a nearly 74% probability of second remission due to retreatment with Keytruda (pembrolizumab), according to the findings of a five-year follow-up study of the phase 2 KEYNOTE-087 trial recently published in the journal Blood.
In the trial, 210 patients — median age 35, 46.2% of whom were female — with R/R cHL and progressive disease following treatment with autologous stem cell transplantation (ASCT) and Adcetris (brentuximab vedotin) (cohort 1, 69 patients), salvage chemotherapy and Adcetris without ASCT (cohort 2, 81 patients) or ASCT without Adcetris (cohort 3, 60 patients), received 200mg of Keytruda intravenously every three weeks for up to two years. Patients who achieved complete response, discontinued treatment were eligible for a second course of Keytruda if they experienced progressive disease.
At a median follow-up of 63.7 months, the overall response rate (ORR, the patients whose disease responded either partially or completely to treatment) was 71.4%, with 27.6% experiencing a complete response and 43.8% seeing a partial response. The median duration of response (DOR) was 16.6 months, and the median progression-free survival (the time a patient lives without the disease spreading or getting worse) was 13.7 months, according to the KEYNOTE-087 results published in Blood.
Researchers reported that a quarter of responders, and half of complete responders, maintained their response for at least four years. Additionally, 19 of the 20 patients who received a second course of Keytruda had evaluable results, including an objective response rate of 73.7% and a median duration of response of 15.2 months.
“Single-agent (Keytruda) can induce durable responses, particularly in patients achieving CR,” the authors wrote. “Second course (Keytruda) frequently re-induced sustained responses after relapse from initial CR.”
KEYNOTE-087 launched in 2015, sponsored by Merck, the company developing the PD-1 inhibitor Keytruda, according to its listing on clinicaltrials.gov.
Keytruda was approved by the Food and Drug Administration (FDA) for the treatment of adults with R/R cHL in 2020, which followed a breakthrough therapy designation by the FDA in 2016.
Keytruda in an immune checkpoint inhibitor which works to prevent cancer cells from suppressing the immune system, according to the National Cancer Institute, and has also been approved to treat types of breast, lung, skin and other cancers.
The American Cancer Society estimated that there will be approximately 8,830 new cases of Hodgkin lymphoma and approximately 900 deaths from the disease in 2023 and reported that cHL accounts for more than 90% of Hodgkin lymphoma cases in developed countries.
“Although most patients with HL are cured with multiagent chemotherapy, a substantial minority remain in need of other therapies. Fortunately, the discovery and subsequent therapeutic exploitation of the programmed cell death 1 pathway has led to agents such as (Keytruda) becoming available for patients with a variety of cancers, including HL,” wrote Chan Cheah, lymphoma lead and fellowship program director of Sir Charles Gairdner Hospital, founder of Blood Cancer Research Western Australia and clinical professor at the University of Western Australia Medical School in a commentary published alongside the trial results in Blood.
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