Influenza

Influenza is a severe respiratory illness with outbreaks of disease primarily during the winter months and is responsible for influenza pandemics. There are three types of influenza viruses: A, B and C. Influenza A and B viruses are significant human respiratory pathogens that cause seasonal flu. Influenza A viruses are  responsible for multiple major influenza pandemics worldwide.

Currently approved antiviral treatments for influenza are partially effective and prone to viral resistance. Strains of flu virus that are resistant to approved treatments, oseltamivir (Tamiflu®), zanamivir (Relenza®) and Xofluza®, have appeared and in some cases are predominant. 

To learn more about influenza, please visit the information page at the Centers for Disease Control and Prevention (CDC). 

We have developed novel, broad-spectrum antivirals that are specifically designed to be effective against all significant pandemic and seasonal influenza strains, and to have a high barrier to resistance due to the way they target the virus’ replication machinery.

CC-42344 - Influenza A PB2 Inhibitor

CC-42344 is a novel, broad-spectrum antiviral investigational candidate for the treatment of pandemic and seasonal influenza A. CC-42344 inhibits the first step in influenza A’s viral replication by binding to a highly conserved PB2 site of the influenza polymerase complex that is essential to replication. We discovered CC-42344 using our proprietary structure-based drug discovery platform technology. 

In vitro testing showed CC-42344’s excellent antiviral activity against influenza A strains, including pandemic and seasonal strains, as well as against strains resistant to Tamiflu® and Xofluza®, while also demonstrating favorable pharmacokinetic and safety profiles. We reported favorable safety and tolerability results in our Phase 1 study with CC-42344 conducted in Australia.

We have completed a Phase 2a human challenge study in the United Kingdom designed to evaluate safety, and viral and clinical measures in healthy subjects challenged with influenza A. While in the Phase 2a study CC-42344 demonstrated a favorable safety and tolerability profile and no serious adverse events (SAEs) or drug-related discontinuations by study participants, due to unexpectedly low influenza infection among study participants, we determined that the low infectivity obtained in this study hindered antiviral data analysis.

We plan to continue development of oral CC-42344 as a treatment for pandemic and seasonal influenza A.

CC-42344 - Inhaled Influenza A PB2 Inhibitor 

Based on our preclinical data, inhaled CC-42344 exhibits highly effective delivery into the lung, superior lung exposure, efficacy in influenza-infected human lung epithelia and a favorable safety profile. We have developed a dry powder inhalation formulation and have completed toxicology studies.

Replication Inhibitor – Influenza A/B 

We are in preclinical development with replication inhibitor compounds for influenza types A and B. In October 2025 we received a non-dilutive $500,000 Small Business Innovation Research Phase I award from the National Institutes of Health’s (NIH) National Institute of Allergy and Infectious Diseases (NIAID) to support the development of a novel, broad-spectrum lead candidate targeting the influenza A/B polymerase complex.