Merck has received the US Food and Drug Administration (FDA) approval for Welireg (belzutifan) to treat a type of von Hippel-Lindau (VHL) disease in adults.
The drug is indicated for VHL disease in adults, who need treatment for related renal cell carcinoma (RCC), CNS hemangioblastomas, or pancreatic neuroendocrine tumours (pNET), and does not require immediate surgery.
Welireg is an oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, that prevents the expression of HIF-2α target genes related to cellular proliferation, angiogenesis and tumour growth.
The drug is administered as once daily tablets with 120mg recommended dose until disease progression or toxicity.
Merck is working to optimise production of Welireg to facilitate a sustainable supply that meets anticipated US demand, with commercialisation expected by early September.
The company claimed that Welireg is the first HIF-2α inhibitor therapy approved in the US.
Merck Research Laboratories clinical research vice president Scot Ebbinghaus said: “WELIREG is the first and only approved systemic therapy for patients with certain types of VHL-associated tumours, representing an important new treatment option for patients affected by this rare condition.
“Today’s approval of WELIREG is a significant milestone and is a testament to Merck’s commitment to bring forward innovative new treatment options for more patients.”
The US FDA approval is based on results from the Study 004, an open-label trial in 61 patients with VHL-associated RCC diagnosed based on a VHL germline alteration.
In the study, overall response rate (ORR), as measured by radiology assessment using RECIST v1.1 is a major efficacy endpoint in patients with VHL-related RCC.
Duration of response (DoR) and time to response (TTR) include the additional efficacy endpoints.
The drug may cause embryo-foetal harm when administered pregnant women, and may impair fertility in males of reproductive potential, based studies in animals.
Women are not advised to breastfeed during treatment with Welireg, for up to one week after the treatment, based on serious adverse reactions in breastfed children.
Furthermore, Welireg may cause severe hypoxia that may require discontinuation, supplemental oxygen, or hospitalisation.
The most common adverse reactions include decrease in haemoglobin, anaemia, fatigue, rise in creatinine, headache, dizziness, nausea and elevated glucose levels.
Study 004 principal investigator Eric Jonasch said: “VHL disease is a rare and serious condition. Until today, there were no systemic therapies approved to help treat patients diagnosed with certain types of VHL-associated tumours.
“The approval of WELIREG, which is based on data showing an overall response rate across three different types of VHL-associated tumours, addresses this significant unmet need by introducing a new option for physicians and their patients impacted by this disease.”
Last month, Merck has received the US FDA approval for Vaxneuvance, its pneumococcal 15-valent conjugate vaccine, for active immunisation in adults.
