Zynyz Approved for Metastatic or Recurrent Locally Advanced Merkel Cell Carcinoma

The Food and Drug Administration (FDA) has granted accelerated approval to Zynyz^™ (retifanlimab-dlwr) for the treatment of adults with metastatic or recurrent locally advanced Merkel cell carcinoma (MCC).

Retifanlimab is a programmed death receptor-1 (PD-1)-blocking antibody. The approval was based on data from the open-label, multiregional, single-arm phase 2 PODIUM-201 trial (ClinicalTrials.gov Identifier: NCT03599713), which included 65 patients with metastatic or recurrent locally advanced MCC who did not receive prior systemic therapy for their advanced disease. Patients received retifanlimab 500mg intravenously every 4 weeks until disease progression, unacceptable toxicity, or up to 24 months.

Findings showed an overall response rate (ORR) of 52% (95% CI, 40-65), with 12 patients achieving complete response and 22 patients achieving partial response. Among responders, 26 patients had a duration of response (DOR) lasting at least 6 months and 21 patients had a DOR lasting at least 12 months. The DOR ranged from 1.1 to 24.9+ months.

Accelerated approval for this indication was based on tumor response rate and DOR. Continued approval may be contingent upon verification and description of clinical benefit in a confirmatory trial.

“Zynyz 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,” said Hervé Hoppenot, Chief Executive Officer, Incyte. “We continue to study the potential of Zynyz in additional tumor types and in combination with other Incyte pipeline compounds.”

The most common adverse reactions reported in the clinical trial were fatigue, musculoskeletal pain, pruritus, diarrhea, rash, pyrexia, and nausea. The most frequent serious adverse reactions were fatigue, arrhythmia, and pneumonitis.

Zynyz is supplied as a solution in a single-dose vial (500mg/20mL). Treatment is administered as an intravenous infusion after dilution. 

The product is expected to be available by early April, according to an Incyte spokesperson.