Acceptance based on objective response rate data from the Phase 2 LITESPARK-015 trial evaluating WELIREG in certain patients with advanced PPGL

If approved, WELIREG would be the only available therapy in the U.S. for eligible patients with advanced PPGL

RAHWAY, NJ, USA I January 27, 2025 I Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the U.S. Food and Drug Administration (FDA) has accepted for priority review a supplemental new drug application (sNDA) seeking approval of WELIREG® (belzutifan), Merck’s oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, for the treatment of adult and pediatric patients (12 years and older) with advanced, unresectable, or metastatic pheochromocytoma and paraganglioma (PPGL). The sNDA is based on objective response rate (ORR) and duration of response (DOR) data from the Phase 2 LITESPARK-015 trial, which will be presented at an upcoming medical meeting. The FDA has set a Prescription Drug User Fee Act (PDUFA), or target action, date of May 26, 2025.

“Pheochromocytoma and paraganglioma are rare tumors that form in and around the adrenal glands, and currently, there are no approved therapies available in the U.S. for patients with this rare disease,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “Today’s U.S. filing acceptance demonstrates our commitment to advancing novel therapies, such as WELIREG, to help treat patients with certain rare oncologic diseases. We look forward to working with the FDA to potentially provide this critical option to these patients who urgently need new innovative therapies.”

WELIREG is the first and only HIF-2α inhibitor therapy approved in the U.S. for the treatment of adult patients with von Hippel-Lindau (VHL) disease who require therapy for associated renal cell carcinoma (RCC), central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors (pNETs) not requiring immediate surgery, based on results from the Phase 2 LITESPARK-004 trial. WELIREG is also approved for certain adult patients with VHL disease-associated tumors in China and 16 additional countries around the world.

WELIREG is also approved in the U.S. and Canada for the treatment of adult patients with advanced RCC following a PD-1/PD-L1 inhibitor and a vascular endothelial growth factor tyrosine kinase inhibitor (VEGF-TKI), based on results from the Phase 3 LITESPARK-005 trial.

Merck is investigating WELIREG in rare oncologic diseases, RCC and other tumor types through a broad clinical development program, including in Phase 2 and 3 trials evaluating WELIREG as monotherapy and in combination with other medicines.

About LITESPARK-015

LITESPARK-015 is an open-label, single-arm, multi-cohort Phase 2 trial (NCT04924075) evaluating the efficacy and safety of WELIREG monotherapy in patients with advanced PPGL (Cohort A1), pNETs (Cohort A2), VHL disease-associated tumors (Cohort B1), advanced gastrointestinal stromal tumors (Cohort C), or advanced solid tumors with HIF-2α-related genetic alterations (Cohort D). The primary endpoint is ORR per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) as assessed by blinded independent central review (BICR). Secondary endpoints include DOR, time to response, disease control, progression-free survival, overall survival and safety. The trial enrolled an estimated 322 patients who received WELIREG 120 mg orally once daily.

About pheochromocytoma and paraganglioma

Pheochromocytoma and paraganglioma (PPGL) are rare adrenal tumors that can be caused by certain genetic syndromes or mutations. It is estimated that up to 2,000 new cases of PPGL are diagnosed each year in the U.S., and up to 52,800 new cases are diagnosed each year worldwide. Pheochromocytoma occur in the center of the adrenal gland, whereas paraganglioma occur in nerve tissue in the adrenal glands and near certain blood vessels and nerves. Up to 25% of PPGL cases are metastatic at diagnosis.

About WELIREG® (belzutifan) 40 mg tablets, for oral use

Indications in the U.S.

Certain von Hippel-Lindau (VHL) disease-associated tumors

WELIREG (belzutifan) is indicated for the treatment of adult patients with von Hippel-Lindau (VHL) disease who require therapy for associated renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas, or pancreatic neuroendocrine tumors (pNET), not requiring immediate surgery.

Advanced Renal Cell Carcinoma (RCC)

WELIREG is indicated for the treatment of adult patients with advanced renal cell carcinoma (RCC) following a programmed death receptor-1 (PD-1) or programmed death ligand 1 (PD-L1) inhibitor and a vascular endothelial growth factor tyrosine kinase inhibitor (VEGF-TKI).

Merck’s focus on cancer

Every day, we follow the science as we work to discover innovations that can help patients, no matter what stage of cancer they have. As a leading oncology company, we are pursuing research where scientific opportunity and medical need converge, underpinned by our diverse pipeline of more than 25 novel mechanisms. With one of the largest clinical development programs across more than 30 tumor types, we strive to advance breakthrough science that will shape the future of oncology. By addressing barriers to clinical trial participation, screening and treatment, we work with urgency to reduce disparities and help ensure patients have access to high-quality cancer care. Our unwavering commitment is what will bring us closer to our goal of bringing life to more patients with cancer. For more information, visit https://www.merck.com/research/oncology.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

SOURCE: Merck