Merck Scores First Invalidation of Halozyme Patent...Positive Signal for Alteogen and Keytruda SC Dispute

First Decision by US Patent Board Among 13 Cases
Momentum Weakens for Halozyme's Infringement Lawsuit Against Alteogen's ALT-B4

The US Patent Trial and Appeal Board (PTAB) has issued its first invalidation ruling on the core 'MDASE' patent family held by Halozyme Therapeutics in its patent dispute with Merck (MSD) in the United States. This weakens Halozyme's basis for its infringement lawsuit against Merck's 'Keytruda SC,' which utilizes Alteogen's subcutaneous (SC) formulation conversion technology 'ALT-B4.'

Product image of Keytruda SC formulation 'Keytruda Qurex' sold in the United States. Photo by Merck US

On May 12 (local time), the PTAB finalized an invalidation decision for one of the 13 Halozyme patents challenged by Merck through a post-grant review (PGR) process.

MDASE pertains to a patent for a modified version of the enzyme hyaluronidase, which is essential for converting intravenous (IV) drugs into subcutaneous (SC) formulations. Halozyme claimed rights not only over a variant with a single specific modification to this enzyme but also expanded the scope of protection to "all proteins at least 95% similar to this variant." In theory, such a broad scope could cover up to 10 to the 63rd power possible targets.

The PTAB took issue with this aspect. It found that Halozyme had only proven efficacy for a single variant with one modification based on actual experimental data, and that the patent specification did not sufficiently describe how variants with multiple simultaneous modifications would function. The board concluded that this constituted a claim exceeding "the scope of technology actually possessed by the inventor" under patent law.

This decision relieves Alteogen and Merck of one of the greatest legal risks facing their Keytruda SC business. Halozyme had filed a lawsuit against Merck in the US District Court for the District of New Jersey in April last year, alleging that Keytruda SC infringed 15 patents from its MDASE family. Alteogen's SC formulation conversion technology, 'ALT-B4,' is applied in Keytruda SC. The invalidated patent was one of the 15 patents cited as the basis for Halozyme's infringement allegations, narrowing the arsenal of claims available to Halozyme in the main litigation.

However, this ruling does not automatically constitute a finding of non-infringement by ALT-B4. The current PGR procedure solely addresses the validity of Halozyme's patent itself, while the question of whether ALT-B4 infringes the patent will be determined separately in the main litigation at the US District Court for the District of New Jersey. Additionally, an inter partes review (IPR) filed by Halozyme challenging the validity of Alteogen's manufacturing process patent for ALT-B4 is still ongoing.

Beyond the invalidated patent, Merck has also filed additional PGRs against 12 other Halozyme patents within the same patent family. Since all these patents stem from the same original application, it is possible that the same grounds for invalidation could apply to the others as well. Decisions on the remaining 12 patents are expected to be issued sequentially by early June this year.

This content was produced with the assistance of AI translation services.