Merck (NYSE:MRK) today reported fourth-quarter and full-year 2025 results that showcased a tale of two portfolios: a surging oncology and respiratory business set against a dramatic collapse in vaccine demand from China.
The Rahway, New Jersey-based pharmaceutical giant posted full-year sales of $65 billion, a 1% increase, while fourth-quarter revenue grew 5% to $16.4 billion.
However, the company issued a cautious 2026 outlook as it absorbs a massive $9.2 billion acquisition charge for respiratory specialist Cidara Therapeutics.
The year was defined by the continued dominance of the PD-1 inhibitor KEYTRUDA, which reached $31.7 billion in annual sales.
Growth was further bolstered by the rapid adoption of WINREVAIR, Merck’s breakthrough treatment for pulmonary arterial hypertension (PAH), which generated $1.4 billion in its first full year.
These gains were nearly erased by a 39% plunge in GARDASIL sales, which fell to $5.2 billion.
Management attributed the decline to a "challenging market dynamic" in China, where elevated inventory levels and shifting consumer discretionary spending forced a temporary pause in shipments that is expected to persist into early 2026.