Merck's Stock Soars: Proof or Promises Driving Growth?

Merck's stock has experienced a substantial surge of approximately 87% over the past twelve months, rising from $79 to $147 per share. While current sales for existing medicines grew at a typical pace, investor confidence has been boosted by the company's forward-looking strategies and pipeline development.

A notable event impacting recent financial performance was Merck's acquisition of Terns Pharmaceuticals for $5.7 billion in the second quarter of 2026. This significant charge, approximately 9% of the year's sales, was incurred to secure MK-4208, a potential treatment for chronic myeloid leukemia, with the associated costs impacting current earnings while the medicine's arrival is anticipated later.

The company is proactively addressing the upcoming 2028 expiration of KEYTRUDA's primary U.S. patent protection, which accounted for over half of its second-quarter revenue. Merck is presenting this transition as manageable, projecting a gradual decline followed by swift recovery. Evidence of a robust pipeline has been a key differentiator, distinguishing Merck from competitors like Johnson & Johnson and Pfizer.

Recent advancements include the FDA approval of LIPFENDRA, the first oral PCSK9 inhibitor, which demonstrated significant LDL cholesterol reduction in trials. Furthermore, Merck's TROP2 antibody-drug conjugate, sac-TMT, reported positive Phase III results in endometrial cancer, and its anti-TL1A antibody, tulisokibart, met primary endpoints for ulcerative colitis. The drug WINREVAIR also showed strong growth, increasing 75% excluding currency in the second quarter of 2026.

Management has highlighted a commercial opportunity exceeding $70 billion from over 20 new products, with several proof points emerging earlier than anticipated. However, full-year 2026 revenue guidance has been narrowed to $66.3 billion-$67.3 billion, indicating a growth rate of 2% to 4%. Slower U.S. KEYTRUDA growth is expected in the latter half of 2026 as it reaches peak utilization in key indications. Additionally, cardiovascular outcomes data for LIPFENDRA is not expected until 2029.