Merck MRK announced that the FDA has expanded the label of its oral cancer drug Welireg (belzutifan) for a third indication in advanced renal cell carcinoma (RCC), the most common type of adult kidney cancer.
The drug has been approved in combination with Eisai’s blockbuster cancer drug Lenvima (lenvatinib) to treat adult patients with advanced RCC with a clear cell component (ccRCC) following a PD-1/PD-L1 inhibitor.
The approval is supported by data from the phase III LITESPARK-011 study, which evaluated the combination therapy against Exelixis’ (EXEL) blockbuster drug Cabometyx (cabozantinib). The study achieved one of its dual primary endpoints of progression-free survival. Data showed that the regimen reduced the risk of disease progression or death by 26%. Though the combination did not meet the other primary endpoint of overall survival (OS), it showed a trend toward improvement.
MRK’s Stock Performance
The company’s shares have risen 41% year to date compared with the industry’s 13% growth.
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Welireg Growth Provides a Catalyst for Merck
The latest approval comes as the drug’s sales are already expanding rapidly. Merck reported $470 million from Welireg sales in the first half of 2026, up 57% year over year, driven by higher demand in the United States and continued launch uptake in international markets.
The new indication could further expand Welireg’s addressable patient population in advanced ccRCC, particularly as it moves the drug into another treatment setting following PD-1/PD-L1 therapy. It also gives Merck another treatment option in a market where Cabometyx is an established therapy.
Welireg is already approved for two other ccRCC indications. As a monotherapy, it is approved for certain patients with advanced ccRCC following treatment with both a PD-1/PD-L1 inhibitor and a VEGF-TKI. It is also approved in combination with Merck’s blockbuster cancer drug Keytruda for the adjuvant treatment of adults with ccRCC at intermediate-high or high risk of recurrence following nephrectomy, with or without resection of metastatic lesions.
The drug is also approved for certain adult patients with von Hippel-Lindau, a rare inherited disorder that can cause tumors to develop in multiple organs. It is also approved to treat patients aged 12 years and older with locally advanced, unresectable or metastatic pheochromocytoma or paraganglioma, rare tumors that arise in hormone-producing tissues that can produce excess hormones.
Merck is also evaluating Welireg as part of a broader clinical program in RCC and selected solid tumors across different treatment settings.
MRK’s Zacks Rank
Merck currently carries a Zacks Rank #3 (Hold).
Merck & Co., Inc. Price
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Our Key Picks Among Biotech Stocks
Some better-ranked stocks in the sector include Precigen PGEN and AC Immune ACIU, each of which carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks Rank #1 (Strong Buy) stocks here.
Over the past 60 days, estimates for Precigen’s 2026 bottom line have improved from a loss of 2 cents to earnings per share of 24 cents. Over the same period, earnings estimates for 2027 have risen from 25 cents to 73 cents. PGEN shares have gained 85% year to date.
Precigen’s earnings beat estimates in three of the trailing four quarters and missed in the remaining one, with the average surprise being 108.96%.
Over the past 60 days, estimates for AC Immune’s 2026 loss per share have narrowed from 84 cents to 60 cents. Over the same period, earnings estimates for 2027 remained unchanged at 17 cents per share. ACIU shares have lost 20% year-to-date.
AC Immune’s earnings beat estimates in each of the trailing four quarters, with the average surprise being 33.25%.
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