Welireg Granted Priority Review for Previously Treated Kidney Cancer

The Food and Drug Administration (FDA) granted a priority review for a supplemental new drug application to Welireg (belzutifan) for the treatment of adults with advanced renal cell carcinoma (RCC; the most common type of kidney cancer) that has previously been treated with an immune checkpoint inhibitor and anti-angiogenic therapy, according to Merck, the manufacturer of the agent.

“Patients with advanced RCC whose cancer progresses following immune checkpoint and anti-angiogenic therapies face a poorer prognosis, and for those patients, there is a crucial unmet need for new options with an alternative mechanism of action,” Dr. Marjorie Green, senior vice president and head of late-stage oncology, global clinical development, Merck Research Laboratories, said in a press release. “The FDA’s priority review designation of this application reinforces the urgency to provide new options to previously treated patients with advanced RCCand we are committed to working closely with the FDA to bring Welireg to these patients as quickly as possible.”

Welireg, which was approved in August 2021 for certain patients with von Hippel-Lindau disease-related kidney cancer, works by inhibiting HIF-2α, a biomarker found on certain types of cancers that is associated with aggressive disease and even resistance to chemotherapy, according to research published by the National Institutes of Health.

READ MORE:FDA’s Welireg Approval A ‘Complete Game Changer’ for Certain Cancers Associated With VHL Disease

The FDA grants priority reviews to drugs that show promise in treating serious conditions. In doing so, the agency agrees to work with the company developing the drug to expedite the review and potential approval of the agent. Now, the FDA set a target action date — which is when they will decide if the drug will be approved or not — of Jan. 17, 2024.

The priority review is based on findings from the randomized, open-label phase 3 LITESPARK-005 clinical trial, which is comparing Welireg to Afinitor (everolimus) in patients with pretreated RCC that has progressed on a PD-1/PD-L1 checkpoint inhibitor and a VEGF-TKI therapy. A total of 746 patients were enrolled in the trial, and they were randomly assigned to receive daily Welireg (administered orally) or daily Afinitor (also administered orally).

The main goals of the trail were progression-free survival (time from treatment until death or disease worsening) and overall survival (time from treatment until death from any cause). Researchers on the trial also analyzed objective response rate (percentage of patients whose disease shrank or disappeared), duration of response (time patients start responding to treatment until death or disease worsening) and safety.

While Welireg did not lead to a statistically significant improvement in overall survival, researchers did observe a significant and clinically meaningful improvement in progression-free survival with Welireg compared with Afinitor. Welireg also demonstrated superior objective response rates, according to the press release.

LEARN MORE:Welireg Made a von Hippel-Lindau Survivor Feel Like a 'Medical Miracle'

LITESPARK-005 is one of four phase 3 trials (the others being LITESPARK-011, LITESPARK-012 and LITESPARK-022) evaluating Welireg in multiple treatment settings, according to Merck.

Side effects observed in trials of Welireg included: anemia, hypoxia, embryo-fetal toxicity, retinal detachment, central retinal vein occlusion, dizziness, pain, fatigue, nausea, abdominal pain, headache and more.

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