FDA Approves Retifanlimab-dlwr for the Treatment of Merkel Cell Carcinoma

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The FDA has granted accelerated approval to retifanlimab-dlwr (Zynyz; Incyte) for the treatment of adults with metastatic or recurrent locally advanced Merkel cell carcinoma (MCC).

Retifanlimab-dlwr is a humanized IgG4 monoclonal antibody that targets human programmed death receptor-1 (PD-1).

“More than a third of patients with MCC present with regional or distant metastases, which are associated with high rates of mortality,” Shailender Bhatia MD, from the University of Washington and Fred Hutchinson Cancer Center, said in a statement. “The approval of [retifanlimab-dlwr] offers health care providers another first-line treatment option against MCC that can result in durable responses in patients with metastatic disease, and I look forward to having [retifanlimab-dlwr] in our treatment portfolio for these difficult-to-treat patients.”

The biologics license application for retifanlimab-dlwr was granted accelerated approval by the FDA based on results that demonstrated tumor response rate and duration of response. The continued approval of retifanlimab-dlwr for this indication will rely on verification and description of clinical benefits in confirmatory trials.

The FDA approval was based on data from the POD1UM-201 (NCT03599713) trial, which is an open-label multiregional, single-arm study that evaluated retifanlimab-dlwr in adults with metastatic or recurrent locally advanced MCC who did not receive prior systemic therapy for advanced disease.

Individuals in the trial received retifanlimab-dlwr 500 mg intravenously every 4 weeks until disease progression, unacceptable toxicity, or for up to 24 months. Investigators performed a tumor response assessment every 8 weeks for the first year of therapy and 12 weeks after.

Among individuals who are chemotherapy-naïve, retifanlimab-dlwr as a monotherapy demonstrated an objective response rate of 52%, determined by the independent central review using RECIST v1.1.

A complete response was seen in 12 individuals, with an additional 22 individuals showing a partial response. Among patients who responsed to treatment, the duration of response (DOR) ranged from 1.1 to 24.9 or more months. Approximately 76% experienced a DOR of 6 months or longer and 62% experienced a DOR of 12 months or longer.

“[Retifanlimab-dlwr] offers patients and health care professionals an additional first-line anti-PD-1 option for patients with metastatic or recurrent locally advanced MCC, which can be a challenging and aggressive disease to treat,” Hervé Hoppenot, CEO of Incyte, said in the statement. “Incyte is grateful to the investigators and patients around the world who participated in the POD1UM-201 trial. We continue to study the potential of [retifanlimab-dlwr] in additional tumor types and in combination with other Incyte pipeline compounds.”

Serious adverse events (AEs) occurred in 22% of those receiving retifanlimab-dlwr. The most frequent serious AEs included fatigue, arrhythmia, and pneumonitis. Permanent discontinuation of retifanlimab-dlwr due to AEs occurred in 11% of individuals.

The most common AEs that occurred in individuals receiving retifanlimab-dlwr were fatigue, musculoskeletal pain, pruritus, diarrhea, rash, pyrexia, and nausea.

Eligible individuals in the United States who are prescribed retifanlimab-dlwr will have access to IncyteCARES, a program offering personalized patient support, including financial assistance, ongoing education, and additional resources.

Reference

Incyte announces FDA approval Of Zynyz (retifanlimab-dlwr) for the treatment of metastatic or recurrent locally advanced Merkel cell carcinoma (MCC). News release. March 22, 2023. Accessed March 22, 2023. https://investor.incyte.com/news-releases/news-release-details/incyte-announces-fda-approval-zynyztm-retifanlimab-dlwr