Senator Questions Merck Over Patent Strategy for Blockbuster Cancer Drug Keytruda

U.S. Senator Maggie Hassan has launched a formal inquiry into Merck’s patenting and pricing practices for its top-selling oncology treatment, Keytruda. The investigation focuses on allegations that the pharmaceutical giant utilizes secondary patenting and product-hopping strategies to delay lower-cost biosimilar competition. This scrutiny highlights growing legislative pressure on drugmakers to reform intellectual property tactics that maintain high costs for life-saving medications.

Senator Maggie Hassan, ranking member of the Senate Finance Subcommittee on Health Care, sent a letter to Merck CEO Robert Davis demanding details on patent actions related to Keytruda. The inquiry specifically targets the transition from the drug’s original intravenous version to a new injectable form, a move Hassan suggests is designed to extend market exclusivity into the 2030s. Citing findings from the International Consortium of Investigative Journalists (ICIJ), the senator expressed concerns that these anti-competitive practices prioritize corporate profits over patient access to affordable care.

The ICIJ’s Cancer Calculus investigation revealed that Merck and associated entities have filed 1,212 patent applications across 53 jurisdictions to protect Keytruda’s market share. While the drug’s primary patents are slated to expire in 2028, secondary patents could potentially push exclusivity in the U.S. until 2042. This extended protection allows Merck to maintain high list prices, which currently range from $80,000 in Germany to as much as $208,000 in the United States, often forcing patients into legal battles or fueling counterfeit markets in regions like Mexico.

In response to previous questioning, CEO Robert Davis maintained that the pharmaceutical ecosystem requires a balance of patent protection and a healthy biosimilar market, asserting he would not block an intravenous biosimilar after key patents expire. However, Hassan’s letter includes ten specific questions regarding how Merck justifies its large volume of secondary patents and whether these tactics are intended to stifle competition. This inquiry coincides with broader legislative efforts, such as the Medication Affordability and Patent Integrity Act, which aims to streamline patent reviews and facilitate the entry of generic alternatives into the pharmaceutical market.