Cocrystal Pharma to launch phase 1b study by year-end 2025, targeting prevention and treatment of viral gastroenteritis caused by norovirus.
The US Food and Drug Administration (FDA) has cleared Cocrystal Pharma to proceed with a phase 1b human challenge study evaluating CDI-988, a novel oral broad-spectrum protease inhibitor being developed for the prevention and treatment of norovirus infections. The trial is expected to begin before the end of 2025.1
Currently, there are no approved vaccines or therapies for norovirus, which causes an estimated 21 million infections annually in the United States, including 109,000 hospitalizations, 465,000 emergency department visits, and roughly 900 deaths. Outbreaks are especially disruptive in confined environments such as cruise ships, hospitals, and military facilities.1
CDI-988 is designed to inhibit the highly conserved 3CL viral protease. Preclinical studies demonstrated broad antiviral activity against major norovirus strains, including GII.4 and GII.17. In a first-in-human phase 1 study, CDI-988 was well tolerated with a favorable safety profile.1
“This milestone marks an important step in advancing CDI-988 into clinical development,” said Sam Lee, PhD, president and co-CEO of Cocrystal Pharma. “The planned challenge study will help determine its efficacy in preventing or treating norovirus infection.”1
FDA has cleared a phase 1b human challenge study of CDI-988, the first potential oral antiviral for norovirus prevention and treatment.
Norovirus causes ~21 million infections annually in the US, with over 100,000 hospitalizations and nearly 900 deaths.
CDI-988 showed broad antiviral activity in preclinical studies and was well tolerated in Phase 1 testing.
Cocrystal’s structure-based drug discovery platform allows near-atomic resolution modeling of drug-target interactions, facilitating the design of first- and best-in-class antivirals. In addition to norovirus, CDI-988 has shown activity against coronaviruses.1
Norovirus, often referred to as the “stomach flu,” spreads rapidly via contaminated food, surfaces, and close person-to-person contact. Immunocompromised individuals, infants, and older adults are at highest risk for severe or prolonged illness. Patients may remain contagious for weeks after symptom resolution, complicating containment efforts.1
Beyond norovirus, CDI-988 is also being developed as a potential therapy for coronavirus infections. In 2023, the candidate received approval from the Australian Human Research Ethics Committee (HREC) to initiate a phase I trial for COVID-19. The drug leverages Cocrystal’s structure-based discovery platform, which enables near-atomic three-dimensional visualization of inhibitor complexes to identify new binding sites and accelerate the development of antivirals for both acute and chronic viral diseases.2
