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.
"In 2025, we continued to advance leading-edge science to deliver transformative medicines," said CEO Robert M. Davis.
"The transformation of our portfolio is well underway, bolstered by the acquisitions of Verona Pharma and Cidara Therapeutics."
To accelerate its post-Keytruda future, Merck utilized two rare FDA Commissioner’s National Priority Vouchers in the fourth quarter to expedite the review of Enlicitide (an oral PCSK9 inhibitor) and Sac-TMT (a TROP2-directed ADC), both of which showed positive Phase 3 results in 2025.
Meanwhile, Merck’s 2026 guidance anticipates worldwide sales between $65.5 billion and $67 billion.
However, non-GAAP EPS is expected to fall to a range of $5 to $5.15—down significantly from 2025’s $8.98—due to a one-time $3.65 per share charge related to the Cidara acquisition.