Cocrystal Pharma Announces Norovirus Oral Antiviral Candidate Demonstrates Potent Activity Against The Emerging GII.17 Variants

• Norovirus GII.17 variants have overtaken GII.4 as the most prevalent strain and significantly increased norovirus outbreaks in the U.S. and European countries in 2024-2025
• Cocrystal Pharma's pan-viral protease inhibitor CDI-988 shows superior broad-spectrum antiviral activity against major norovirus variants including GII.4 and GII.17 strains
• Company reported favorable safety and tolerability of CDI-988 in Phase 1 and plans to initiate a human challenge study in 2025 for the treatment and prevention of norovirus infection
  
   Cocrystal Pharma, Inc. (NASDAQ:COCP) ("Cocrystal" or the "Company") announces that its investigative drug candidate CDI-988 was shown to bind to the highly conserved region of the GII.17 protease with excellent potency, similar to that shown across a range of GII.4 norovirus variants that had been the dominant worldwide strains until this year. The high resolution GII.17 protease crystal structures used in determining CDI-988's activity were obtained using the Company's proprietary structure-based platform technology. Cocrystal plans to initiate a human norovirus challenge study in 2025 in the U.S. to evaluate CDI-988 as a potential prevention and treatment of norovirus infection.

"Norovirus is the most common cause of acute gastroenteritis worldwide, yet there are no approved antiviral treatments or vaccines available to combat it," said Sam Lee, Ph.D., Cocrystal's President and co-CEO. "Norovirus antiviral and vaccine development has been extremely challenging due to high diversity among variants that include 10 genogroups and 49 genotypes. We are gratified to have determined the first crystal structure of GII.17 protease and demonstrated broad-spectrum antiviral activity of CDI-988 against newly circulating major norovirus GII.17 variants. Based on a novel mechanism of action and superior broad-spectrum antiviral activity, CDI-988 is a compelling candidate for advancement as a first-in-class oral antiviral to be used for both prevention and treatment of norovirus infection."

"Norovirus is a noteworthy research target considering that each year an estimated 685 million cases and approximately 50,000 child deaths are attributed to this virus worldwide, leading to a societal cost estimated at $60 billion," said James Martin, Cocrystal's CFO and co-CEO. "We are addressing the urgent need for norovirus and other emerging viral outbreaks through our platform technology that facilitates the rapid, efficient development of potentially highly effective and safe direct-acting antivirals."