[Feature Stock] Alteogen rises over 7%... US Patent Trial and Appeal Board invalidates Halozyme patent, mitigating Keytruda SC risk

Alteogen shares rose by more than 7% after news of a decision by the U.S. Patent Trial and Appeal Board (PTAB) to invalidate Halozyme’s patent, regaining the top spot in the NASDAQ market capitalization rankings. The market believes this reflects an expectation that some of the patent risks arising during the commercialization process of Merck’s Keytruda subcutaneous (SC) formulation may be partially alleviated.

According to reports from the Korea Exchange, Alteogen traded at around 380,000 Korean won in early trading, up more than 7% from the previous trading day. Its market capitalization also increased rapidly, once again placing it at the top among NASDAQ leaders.

The direct background behind the stock surge is the U.S. patent trial outcome announced by Alteogen. The company said that in the Post-Grant Review (PGR) challenging Halozyme’s U.S.-registered patent (US 11,952,600), the PTAB ruled that the patent was invalid. This is the first final written decision among multiple PGRs filed by Merck.

The patent is an MDASE patent related to human hyaluronidase. During the commercialization of Merck’s Keytruda SC formulation “Keytruda Qurex,” it has been cited as a potential source of contention. It is understood that the PTAB considered the scope of the patent claims to be overly broad and that the specification drafting requirements and enablement requirements were not sufficiently met.

PGR is a system that allows third parties to challenge the validity of a patent within 9 months after it is granted in the U.S. This system not only reviews novelty and inventiveness but also broadly examines the specification drafting and enablement requirements. As a result, some assessments believe that this ruling could affect not only the single patent in question but also the market’s interpretation of Halozyme’s entire patent portfolio.

Alteogen owns a human hyaluronidase platform called “ALT-B4,” which can convert intravenous (IV) injection into subcutaneous (SC) injection. Based on this technology, the company has signed technology transfer agreements with global pharmaceutical companies, including Merck. In particular, progress in the commercialization of Keytruda SC has long been seen as a core variable directly tied to future royalty revenue.

Previously, the market had worried that Halozyme’s hyaluronidase patent portfolio might become a patent barrier to the development of SC formulations. With this invalidation decision partially removing commercialization uncertainty for partners, attention on the platform’s value and its medium- to long-term profit expectations has returned.

However, given that this ruling is only the first case among multiple patent trials initiated by Merck, analysis suggests that results of other patent trials still need to be monitored going forward.