Zynyz Receives FDA Accelerated Approval for Merkel-Cell Carcinoma

April 2023, Vol 14, No 2


On March 22, 2023, the FDA granted accelerated approval to retifanlimab-dlwr (Zynyz; Incyte Corporation), a programmed cell death 1–blocking antibody, for the treatment of adult patients with metastatic or recurrent locally advanced Merkel-cell carcinoma (MCC). The FDA granted this approval a priority review, fast-track designation, and orphan drug designation.

“More than a third of patients with MCC present with regional or distant metastases, which are associated with high rates of mortality,” said Shailender Bhatia, MD, Director, Melanoma and Renal Cancer Team, Fred Hutchinson Cancer Center, University of Washington, Seattle. “The approval of Zynyz offers healthcare 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 Zynyz in our treatment portfolio for these difficult-to-treat patients.”

This approval was based on results of the PODIUM-201 study, an open-label, multiregional, single-arm clinical trial of patients with metastatic or recurrent locally advanced MCC who had not received previous systemic therapy for their advanced disease.

Participants were administered retifanlimab 500 mg as an intravenous infusion every 4 weeks until disease progression, unacceptable toxicity, or for up to 24 months.

The primary end point was objective response rate as determined by independent central review committee per RECIST version 1.1. Secondary end points included duration of response (DOR), disease control rate, progression-free survival, overall survival, safety, and pharmacokinetics. Among chemotherapy-naïve patients (N = 65), retifanlimab monotherapy resulted in an objective response rate of 52% (95% confidence interval, 40%-65%), with a complete response rate of 18% and a partial response rate of 34%. Among those who responded to treatment, 76% achieved a DOR of 6 months or longer, and 62% had a DOR of 12 months or longer.

The most common (≥10%) adverse reactions occurring in patients receiving retifanlimab were fatigue, musculoskeletal pain, pruritus, diarrhea, rash, pyrexia, and nausea. Serious adverse reactions occurred in 22% of those receiving retifanlimab. The most common (≥2%) serious adverse reactions were fatigue, arrhythmia, and pneumonitis.

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