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Apr 21, 2026 4:00 PM

Why Is Merck Stock Falling Tuesday?

Merck & Co. Inc. (NYSE:MRK) and Eisai on Tuesday announced results from the Phase 3 LITESPARK-012 trial of combination drugs for advanced clear cell renal cell carcinoma (RCC).

Clear cell RCC is the most common form of kidney cancer, accounting for roughly 75–80% of cases.

Triplet Regimen Misses Primary Endpoints

The trial evaluated the triplet therapy of Keytruda (pembrolizumab) plus Lenvima (lenvatinib) plus Welireg (belzutifan).

The study also evaluated MK-1308A, the coformulation of Keytruda and quavonlimab plus Lenvima.

Both combination regimens were compared to Keytruda plus Lenvima.

At a pre-specified interim analysis, the combination regimens did not meet the dual primary endpoints of progression-free survival (PFS) and overall survival (OS).

The safety profiles of the combination regimens were consistent with those observed in previously reported studies.

A full evaluation of the data from this study is ongoing, and Merck and Eisai ...