The new formulation of Keytruda, currently under FDA review, is sparking conflict with Halozyme, which makes enzymes that convert intravenous drugs into injectable versions.
An investigational injectable formulation of Merck’s blockbuster cancer drug Keytruda is creating legal headaches for the company as Halozyme Therapeutics contends the subcutaneous version infringes on its patents for a specific enzyme, according to The Wall Street Journal. Public discussion of the dispute between the two companies is expected Wednesday at an investor conference.
Keytruda was the highest selling drug worldwide last year, raking in nearly $30 billion in sales. With patent protections set to expire in 2028, Merck’s moves to tweak its formulation could goose sales while the protections hold and potentially extend the patent runway.
Merck began collaborating with the South Korean company Alteogen in 2020 to incorporate its hyaluronidase enzymes into an injectable Keytruda formulation. Last year, Merck alleged to the U.S. Patent and Trademark Office that seven patents for Halozyme’s own hyaluronidase enzyme Mdase are too broad and therefore should not have been granted, according to the WSJ.
Halozyme countered Merck’s claims, saying that a new Keytruda formulation that uses the hyaluronidase enzyme infringes on those patents, and that Merck needs to sign a licensing agreement.
These petitions suggest the company is “tipping their hand that the Halozyme patents might be a problem for them,” Zachary Silbersher, co-founder of patent consulting firm Markman Advisors, told the WSJ.
The status of Alteogen’s enzymes in the U.S. is unclear.
In November 2024, Merck’s Phase III trial showed that the subcutaneous injection performed equally as well as the more invasive infusion delivery of Keytruda. Merck has estimated that if the injectable version is approved, up to 40% of patients taking Keytruda will switch within two years, according to the WSJ. The FDA is currently reviewing the application for the new formulation and Merck CEO Robert Davis said at the J.P. Morgan Conference in January that he expects to launch it this year, according to Seeking Alpha.
Mdase is a follow-up product to Halozyme’s Enhanze, which the company says can enable 4-6 hour intravenous treatments to be given in minutes instead. Halozyme has standing partnerships to incorporate Enhanze into Bristol Myers Squibb’s cancer drug Opdivo and Roche’s multiple sclerosis drug Ocrevus.
