Merck MRK, along with its partner Eisai, announced that the phase III LITESPARK-012 study, which evaluated Keytruda-based triplet regimens for the first-line treatment of patients with advanced clear cell renal cell carcinoma (RCC), failed to meet its primary endpoints.
The LITESPARK-012 study evaluated either the triplet therapy of Keytruda plus Lenvima plus Welireg or MK-1308A (a coformulation of Keytruda and quavonlimab – MRK’s investigational anti-CTLA-4 antibody) plus Lenvima versus Keytruda plus Lenvima for the first-line treatment of patients with advanced clear cell RCC.
At a pre-specified interim analysis, treatment with the combination regimens failed to meet the dual primary endpoints of progression-free survival (PFS) and overall survival (OS) for the first-line treatment of patients with RCC versus Keytruda plus Lenvima.
The news sent Merck’s stock down nearly 4% following the announcement yesterday.
Year to date, shares of Merck have risen 6.9% against the industry’s decline of 3.8%.
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MRK & Eisai’s Other Studies in LITESPARK Clinical Program
Keytruda is presently approved as adjuvant monotherapy and in combination regimens for certain patients with RCC in several countries across the world. Keytruda plus Lenvima is approved for the first-line treatment of adult patients with advanced RCC. Welireg is approved for treating certain patients with advanced clear cell RCC.
Earlier this year, the FDA accepted two supplemental new drug applications (sNDA) for review, seeking approval for Welireg plus Lenvima for the treatment of adult patients with advanced RCC with a clear cell component following a PD-1 or PD-L1 inhibitor. The FDA set a target action date of Oct. 4, 2026.
The sNDA was based on data from the phase III LITESPARK-011 study.
Although the data from the LITESPARK-012 study will not impact MRK and Eisai’s other ongoing studies in the LITESPARK clinical program, it could pose a setback for Merck as it continues its efforts to support Keytruda’s long-term growth and reduce risks ahead of the drug’s loss of patent exclusivity in 2028.
Keytruda generated sales of $31.7 billion in 2025, reflecting a 7% year-over-year increase. The drug alone accounts for around 55% of Merck’s pharmaceutical sales. Management expects the drug to reach peak sales of $35 billion by 2028. However, once biosimilars enter the market, Keytruda’s sales are likely to decline sharply.
FDA Approves MRK’s Two-Drug, Once-Daily HIV Pill
In a separate press release, Merck announced that the FDA has approved Idvynso, a new once-daily, oral, two-drug, single-tablet regimen of doravirine (100 mg) and islatravir (0.25 mg) for treating virologically suppressed adults with HIV-1 infection.
Idvynso is now approved for treating adults with virologically suppressed HIV-1 with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine.
Following the nod, Idvynso became the first and only non-INSTI, tenofovir-free, once-daily, complete two-drug regimen to show non-inferior efficacy compared with Gilead Sciences’ GILD three-drug regimen Biktarvy (BIC/FTC/TAF) in a head-to-head phase III study.
Idvynso will be available in pharmacies after May 11. The FDA approval marks a major milestone for the company, as the drug is expected to broaden treatment options for HIV beyond currently available oral therapies, including GILD’s Biktarvy.
Merck & Co., Inc. Price
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MRK’s Zacks Rank & Stocks to Consider
Merck currently carries a Zacks Rank #3 (Hold).
Some better-ranked stocks in the biotech sector are Agenus AGEN and Amarin AMRN, each sporting a Zacks Rank #1 (Strong Buy) presently. You can see the complete list of today’s Zacks #1 Rank stocks here.
Over the past 60 days, estimates for Agenus’ 2026 earnings per share have risen from 54 cents to $1.30, while loss per share estimates for 2027 have narrowed from $1.91 to $1.52 during the same time. AGEN shares have soared 24.5% year to date.
Agenus’ earnings beat estimates in two of the trailing four quarters, while missing the same on the remaining two occasions, with the average surprise being 31.42%.
Over the past 60 days, Amarin's loss per share estimates for 2026 have narrowed from $7.32 to $6.36, while the same for 2027 have narrowed from $5.97 to $4.64 during the same time. AMRN stock has risen 3.9% year to date.
Amarin's earnings beat estimates in three of the trailing four quarters, while missing the same on the remaining occasion, with the average surprise being 51.29%.
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