Cocrystal Pharma's Recent Virology Study Shows Broad-Spectrum Influenza PB2 Inhibitor CC-42344 Exhibits Strong Antiviral Activity Against Highly Pathogenic H5N1 Avian Influenza A Strain

• CC-42344 was shown to be highly active against the highly pathogenic 2024 Texas H5N1 avian influenza strain
• The Company's virology study further confirmed the previous structural and in vitro data that revealed the binding of CC-42344 to PB2 protein of the 2024 H5N1 avian influenza virus

BOTHELL, Wash., May 29, 2025 (GLOBE NEWSWIRE) -- Cocrystal Pharma, Inc. (NASDAQ:COCP) announces that a recent virology study showed its novel, broad-spectrum influenza PB2 inhibitor CC-42344 exhibits strong antiviral activity against the highly pathogenic H5N1 avian influenza A strain (A/Texas/37/2024).

On March 25, 2024, the highly pathogenic avian H5N1 influenza virus was confirmed in a dairy cow in Texas and has continued to spread widely in U.S. dairy cattle, causing a few human cases. There is concern that the H5N1 virus could adapt for human-to-human transmission and potentially result in an influenza pandemic. CC-42344 is a new investigational drug candidate for the treatment of pandemic and seasonal influenza infections. This inhibitor binds to a highly conserved active site of the PB2 protein and inhibits the viral replication process. The Company previously announced the structural and in vitro data of CC-42344 with the purified H5N1 PB2 protein.

The virology study utilized the highly pathogenic H5N1 avian strain (influenza A/Texas/37/2024) and was conducted to test antiviral activity of CC-42344 using Tamiflu® as a reference inhibitor. The data showed that CC-42344 was highly potent against the H5N1 avian influenza virus (EC50, 0.003 µM), approximately 1,000-fold more potent, compared to a refence compound Tamiflu (EC50, 2.69 µM). CC-42344 is currently in development as an oral treatment for pandemic avian and seasonal influenza A infections with initial data showing a favorable safety and tolerability profile.