Merck and Halozyme Locked in Heated Patent Battle Over Keytruda's Injectable Version

Merck & Co. and Halozyme are engaged in a fierce patent dispute regarding the injectable formulation of Keytruda, Merck's leading cancer drug. Halozyme claims that Merck’s new under-the-skin version infringes on its proprietary technology involving human hyaluronidase, a protein that facilitates subcutaneous drug delivery.

During the TD Cowen 45th Annual Healthcare Conference, Halozyme CEO Helen Torley expressed the company’s willingness to pursue legal action if a licensing agreement with Merck cannot be reached. "We are prepared to go to court if necessary," she stated.

In response, Merck has filed petitions to invalidate certain patents held by Halozyme. A Merck representative reaffirmed confidence in their legal stance, declaring, "We strongly believe any Halozyme patents related to this variant are invalid."

The subcutaneous formulation of Keytruda aims to enhance patient access to the PD-1 inhibitor, especially as the intravenous version is set to lose patent protection in 2028. Merck plans to launch this new formulation by 2025, with promising clinical data indicating that it matches the intravenous version on key pharmacokinetic endpoints.

Merck anticipates that the majority of demand for this injectable form will come from early-stage cancer patients, who often receive PD-1 inhibitors like Keytruda as standalone treatments. By 2028, Merck estimates that these patients will comprise about 50% of the total Keytruda user base.

To develop this new product, Merck licensed a hyaluronidase variant, ALT-B4, from Alteogen. Halozyme maintains that its Mdase group of modified human hyaluronidases, which includes around 100 patents valid until 2032 in Europe and 2034 in the U.S., provides a strong foundation for its claims.

For now, both companies are holding firm as negotiations continue. Halozyme hopes to establish a licensing agreement with royalty rates ranging from 3% to 7%. If talks fail, they are ready to seek an injunction against Merck to prevent the sale of subcutaneous Keytruda.