FDA Grants Priority Review to Adjuvant Pembrolizumab for Stage II High-Risk Melanoma

The FDA has granted priority review to a supplemental biologics license application (sBLA) for pembrolizumab for the use as an adjuvant treatment in adult and pediatric patients with stage IIB or IIC melanoma following complete resection.¹

The application is supported by data from the phase 3 KEYNOTE-716 trial (NCT03553836), which demonstrated that adjuvant pembrolizumab monotherapy resulted in a statistically significant and clinically meaningful improvement in recurrence-free survival (RFS) vs placebo in this patient population, meeting the primary end point of the trial. Moreover, no new safety signals were reported with the agent.

Data from KEYNOTE-716 will be shared at an upcoming medical conference, according to Merck.

Under the Prescription Drug User Fee Act, the regulatory agency is anticipated to reach a decision on the sBLA for the immunotherapy by December 4, 2021.

“KEYNOTE-716 is the first phase 3 study to evaluate adjuvant therapy solely for stage IIIB and IIC melanoma – an area with high unmet need,” Jason Luke, MD, director of the Cancer Immunotherapeutics Center at the UPMC Hillman Cancer Center, stated in a press release. “By moving immunotherapy with [pembrolizumab] to earlier stages of melanoma, we have the opportunity to reduce the risk of recurrence for [patients with] high-risk stage II [disease] compared with observation alone following complete resection.”

In the 2-part phase 3 trial, investigators set out to evaluate pembrolizumab as an adjuvant treatment in patients with completely resected, high-risk, stage II melanoma. To be eligible for enrollment, patients could not have received prior treatment for their disease beyond resection, at least 12 weeks needed to have passed between resection and trial randomization, and they could not have evidence of metastatic disease on imaging.²

Moreover, patients had to have an ECOG performance status of 0 or 1 and have acceptably recovered from toxicity and/or complications from surgery before the start of the study. Patients could not have a known additional malignancy that was progressing or required active antineoplastic therapy, nor could they have a diagnosis of immunodeficiency or have received prior PD-1/L1 or CTLA-4 agents.

In the first part of the study, which was double blind, adult participants were randomized to receive either intravenous pembrolizumab at a dose of 200 mg or placebo every 3 weeks for up to 17 cycles, which translated to approximately 1 year. Pediatric patients were randomized to receive pembrolizumab at a dose of 2 mg/kg, with a maximum of 200 mg, or placebo for the same duration.

In part 2, which was open label, adult and pediatric patients who were determined to be eligible for inclusion were given up to 35 additional cycles of treatment with pembrolizumab; this translated to approximately 2 years. If patients recurred after receiving placebo or they completed 17 cycles of pembrolizumab, they were eligible to participate in the second portion of the research. If patients who received pembrolizumab experienced disease recurrence within 6 months of treatment completion, they were excluded.

The primary end point of the trial was RFS, and key secondary end points included distant metastasis-free survival, overall survival, safety, and quality of life.

“At Merck we are innovating to fight cancer earlier, and our data continue to build in this important area of research,” Roy Baynes, senior vice president and head of global clinical development, as well as chief medical officer at Merck Research Laboratories, stated in the press release. “Many patients with stage II melanoma have a high risk of their cancer returning after surgery. This is an important milestone for patients, and we look forward to sharing these results with the medical community as soon as possible. We thank the patients and investigators for their participation in this study.”

References

1. Merck’s KEYTRUDA (pembrolizumab) significantly prolonged recurrence-free survival (RFS) compared to placebo as adjuvant therapy for patients with stage II resected high-risk melanoma in phase 3 KEYNOTE-716 trial. News release. Merck. August 5, 2021. Accessed August 5, 2021. https://bit.ly/3rUeu7j
2. Safety and efficacy of pembrolizumab compared to placebo in resected high-risk stage II melanoma (MK-3475-716/KEYNOTE-716). ClinicalTrials.gov. Updated November 12, 2020. Accessed August 5, 2021. https://www.clinicaltrials.gov/ct2/show/NCT03553836