Merck Faces Patent Lawsuit Over Easier-to-Use Keytruda

A biotech company is suing Merck & Co. over its easier-to-use version of its blockbuster cancer treatment Keytruda, alleging the pharmaceutical giant violated its intellectual property.

Merck knowingly infringed Halozyme Therapeutics Inc.’s patents in crafting a version of Keytruda that can be administered as a shot rather than through an intravenous infusion, according to a lawsuit filed in the U.S. District Court for the District of New Jersey on Thursday.

The shot version of the drug is key to Merck’s future growth. The company said in a statement that it believes the suit has no merit and that Merck is confident in its legal position.

Merck studied the IV form of Keytruda on the International Space Station in order to develop the shot.

At issue is an enzyme used to turn intravenous drugs like Keytruda into medicines that can be administered subcutaneously through a small needle inserted into the skin. Halozyme, which has licensed its enzymes to pharma companies including Bristol Myers Squibb Co. and Johnson & Johnson, claims Merck’s version violates 15 patents granted to the company over more than a decade.

Keytruda, which brought in nearly $30 billion for Merck in 2024, has become a cornerstone of cancer treatment and the best-selling product in pharmaceutical history.

But the drug, which accounts for nearly half of the company’s revenue, is expected to face lower-cost competition and government pricing negotiation in 2028. Merck is seeking to switch as many patients as possible onto the shot once it’s approved, meaning any interference in the process could derail the company’s long-term plan.

Halozyme Chief Executive Officer Helen Torley said in March the company hoped to strike a licensing agreement with Merck and would only take legal action if that doesn’t turn out as planned.

Top photo: Merck headquarters in Rahway, New Jersey.