The pharmaceutical industry confronts its largest patent cliff in decades, with more than $500 billion in projected annual global sales at risk of losing patent protection by 2033, according to Norstella. Merck's Keytruda, the world's bestselling drug generating nearly $32 billion last year, loses U.S. patent protection in 2028. Novo Nordisk faces the highest exposure among major drugmakers, with 77% of its 2025 sales set to lose protection by 2033, driven largely by Ozempic's early 2030s expiration. Bristol Myers Squibb and Merck each have over 65% of last year's sales exposed. Bristol Myers also faces the loss of blood-thinner Eliquis, which brought in over $14 billion last year and is co-marketed with Pfizer, splitting profits equally. This cliff has fueled record dealmaking, the highest in seven years, as companies like Moderna and Revolution Medicines attract takeover interest.

Firms are deploying strategies to extend revenue, though patent expirations vary by country, creating risks like U.S. patients accessing cheaper drugs via Canadian online pharmacies.