Keytruda Outcompetes Adcetris in Refractory or Relapsed Hodgkin Lymphoma Study

By Ruchi Jhonsa, Ph.D.

The cancer of the immune system, Hodgkin lymphoma (HL) is most commonly found in teens and young adults. It affects the lymphatic system and compromises the production of lymphocytes required for fighting infection. In the year 2018, approximately, 80,000 cases of Hodgkin lymphoma were reported worldwide out of which 26,000 died. Traditionally, the standard form of therapy for patients with HL includes salvage chemotherapy followed by autologous stem-cell transplantation (ASCT). However, if the cancer is refractory, which means that if neither treatment works, then Adcetris, [trade name of Seattle Genetics’ immunotherapy drug, brentuximab vedotin (BV)] is recommended. Despite significant advances in the combination of chemo-radiotherapy, a large percentage of patients relapse or have primary refractory disease.

In 2017, Merck got accelerated approval by the FDA for use of Keytruda in adult and pediatric patients whose cancer was refractory or had relapsed following standard treatments like ASCT or BV. This was exciting because Keytruda outcompeted Nivolumab, a PD-1 blocking antibody developed by Bristol-Myers Squibb in terms of response rate. Since Keytruda was able to reduce tumor size in refractory patients treated with BV, Merck decided to launch a trial to confirm the drug’s superiority over BV. Based on an interim analysis conducted by an independent Data Monitoring Committee, today, Merck announced Keytruda’s success in Phase 3 KEYNOTE-204 trial evaluating its efficacy in adult patients with relapsed or refractory classical Hodgkin Lymphoma (cHL). Investigation of the drug in phase 3 study revealed clinically meaningful improvement in progression-free survival in comparison to BV.

Despite positive results, speculations on the use of Keytruda in the front line of treatment for cHL remain. This is because, although Nivolumab showed a lower complete response rate in comparison to Keytruda, it showed a response rate of more than 90% when combined with BV. In that case, the further tests of the combo in the CheckMate 812 trial might establish the combination as the regimen of choice, leaving Keytruda behind.

KEYNOTE-204 Phase 3 Trial

Keytruda is an anti-PD1 immunotherapy drug that activates T cell against both cancerous and non-cancerous cells by masking the PD-1 ligand suppressing the T cell activity. It was granted accelerated approval for cHL treatment in 2017. In 2018, a chimera of anti-CD-30 antibody and cytotoxic agent, monomethyl auristatin E, BV was granted FDA approval for treatment of cHL. Although BV demonstrated an overall response rate of 75% after ASCT treatment, it failed to improve the median duration of response. This led to the launch of the KEYNOTE-204 trial that was designed to compare the efficacy of the two drugs for the treatment of patients with relapsed or refractory cHL. In this open label-study, 304 patients were randomly administered either Keytruda or BV on Day 1 of each three-week cycle for up to 35 cycles. Although not many details about the trial were shared, the vice president of the oncology clinical research at Merck Research Laboratories mentioned a statistically significant and clinically meaningful improvement in progression-free survival with Keytruda compared in a head-to-head fashion, with the currently approved therapy of BV. Of the two primary endpoints, only PFS has been measured and studies are ongoing to determine rather an important endpoint of overall survival (OS).

Despite Keytruda’s failure in two multiple myeloma studies, Merck is determined to test the drug across hematologic malignancies through a broad clinical program, including three registrational trials in cHL and primary mediastinal large B-cell lymphoma, and more than 60 investigator-initiated studies across 15 tumors.

Related Article: Yet Another Feather in Merck’s Crown, Keytruda Meets Endpoint in Phase 3 Trial for Triple Negative Breast Cancer

References

1. https://www.mrknewsroom.com/news-release/oncology/mercks-keytruda-pembrolizumab-significantly-improved-progression-free-survival
2. https://www.fda.gov/drugs/resources-information-approved-drugs/pembrolizumab-keytruda-classical-hodgkin-lymphoma

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Author

Ruchi Jhonsa