Merck (NYSE:MRK) has announced that the FDA expanded the label for its oral HIF-2α inhibitor, Welireg (belzutifan), specifically in certain patients with advanced renal cell carcinoma (“RCC”).
Welireg is now approved in the United States for the treatment of adult patients with advanced RCC whose cancer has progressed after receiving treatment with a PD-1/L1 inhibitor and a VEGF-TKI inhibitor. According to Merck’s management, this approval is notable as it represents the first time a new treatment has been approved in a novel therapeutic class for advanced RCC since 2015.
Merck aims to position Welireg as a new treatment option capable of reducing the risk of disease progression or death in an indication characterized by low survival rates.
The FDA’s approval is founded on data from the phase III LITESPARK-005 study, which investigated Welireg in adult patients with advanced RCC that progressed following treatment with a PD-1/L1 checkpoint inhibitor and VEGF-TKI therapy. This information was disclosed in August. The study demonstrated that Welireg achieved statistically significant and clinically meaningful improvement in progression-free survival (“PFS”), one of the study’s dual primary endpoints. Additionally, the study met its secondary endpoint by showing a statistically significant improvement in the objective response rate (“ORR”).
Welireg is already approved in the United States and Europe for the treatment of adult patients with von Hippel-Lindau (“VHL”) disease who require therapy for associated RCC, central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors not requiring immediate surgery.
Merck’s shares have experienced a 4.6% loss year to date, in contrast to the industry’s 5.9% growth.
The LITESPARK-005 study is part of Merck’s comprehensive late-stage development program for Welireg in RCC, including three other late-stage studies – LITESPARK-011, LITESPARK-012, and LITESPARK-022. LITESPARK-011 and LITESPARK-012 evaluate Welireg in the second-line and treatment-naïve advanced disease settings, respectively, while LITESPARK-022 assesses Welireg in the adjuvant setting.
In a separate press release, Merck, in collaboration with partner Moderna (MRNA), reported three-year follow-up data from the phase IIb KEYNOTE study evaluating their investigational individualized neoantigen therapy (INT) candidate mRNA-4157/V940 in melanoma indication.
At a median planned follow-up of approximately three years, treatment with the combination of mRNA-4157 and Keytruda reduced the risk of recurrence or death by 49% compared with those treated with Keytruda alone. Treatment with this mRNA-4157/Keytruda combination also reduced the risk of developing distant metastasis or death by 62%, compared to Keytruda alone.
These results highlight the substantial benefit of combining mRNA-4157 with Keytruda over an extended period, demonstrating improved outcomes compared to Keytruda alone. In the first half of 2023, Moderna/Merck previously reported two-year follow-up data from the KEYNOTE-942 study, showing that treatment with the mRNA-4157/Keytruda combination reduced the risks of recurrence/death by 44% and the risk of distant metastasis or death by 65%.
Merck and Moderna initiated a strategic partnership in 2016 to develop and commercialize mRNA-based therapeutics for various cancer types. Last year, Merck exercised its option to develop the INT with Moderna, with both companies sharing costs and profits equally, as per the terms of their collaboration.
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