NEW YORK – Merck said on Tuesday that the US Food and Drug Administration has approved pembrolizumab (Keytruda) as neoadjuvant and continued adjuvant treatment for high-risk, early-stage triple-negative breast cancer and that the agency has also converted the drug's accelerated approval for metastatic, PD-L1-high TNBC into a full approval.
The trial demonstrated that after a median follow-up of 39 months, patients who received a combination of pembrolizumab and chemotherapy before surgery, then continued on with single-agent pembrolizumab after surgery, saw a 37 percent reduction in the risk of events including disease progression, recurrence, second primary cancer, or death from any cause compared to patients receiving neoadjuvant chemotherapy alone and adjuvant placebo.
The company said this is the first time the FDA has approved an immunotherapy regimen for high-risk early-stage TNBC patients. The FDA earlier this year decided to defer a regulatory decision on Merck's application seeking approval in this indication since the event-free survival data were not mature in Keynote-522 and its Oncologic Drugs Advisory Committee felt the trial's other primary endpoint, pathologic complete response, did not fully reflect the drug's activity.
Separately, the agency also decided on Tuesday that the final data from the Keynote-355 trial support the use of pembrolizumab plus chemo in metastatic TNBC patients whose tumors express a PD-L1 combined positive score of at least 10. Accordingly, the agency converted a previous accelerated approval in that later-stage indication into a full approval.
In November 2020, the agency had granted accelerated approval for pembrolizumab plus chemotherapy for this patient population based on progression-free survival data from the Keynote-355 trial. According to the drugmaker, that trial has now shown that the regimen led to an overall survival benefit, too. Merck will present the results at an upcoming medical meeting.