Influenza (Antiviral) Program

Our lead Cloudbreak candidates are Antiviral Fc Conjugates (AVCs) for the prevention and treatment of influenza.


Influenza (Antiviral) Program

Our lead Cloudbreak candidates are Antiviral Fc-Conjugates (AVCs) for the prevention and treatment of influenza.

Cloudbreak Influenza (Antiviral) Program

Cidara seeks to develop novel AVCs that provide a direct and sustained antiviral effect, in addition to engaging the immune system, for effective prevention and treatment. These AVCs may offer several potential advantages over vaccines, small molecule antivirals, and monoclonal antibodies.

Potential Advantages of Cloudbreak Antiviral Fc Conjugates (AVCs)

  • Long-actingA single dose may provide months of protection from flu, with antibody-like half-life.
  • Potent TM Activity: AVCs may protect immune compromised patients who cannot mount a sufficient immune response to a vaccine, and provide protection against flu strains that are missed by the seasonal vaccine.
  • Broad Coverage: AVCs may protect against seasonal and pandemic influenza A and seasonal influenza B viruses, including Tamiflu resistant viruses.
  • Superior Resistance Profile: AVCs are expected to be less prone to resistance due to targeting of highly conserved regions of the virus and bi-functional modality.
  • Manufacturing: AVCs may avoid vaccine manufacturing issues and annual flu strain variability concerns.

CB-012 Exhibits Highly Potent In Vivo Activity in a Lethal Mouse Model of H3N2

The anti-influenza activity of AVC CB-012 is superior to Tamiflu. In this lethal mouse model of H3N2, a single dose of CB-012 provided equivalent protection to Tamiflu from death at 1/1000th the cumulative dose.

H3N2 is poorly covered by the seasonal flu vaccine due to the fact that it rapidly mutates. According to the U.S. Centers for Disease Control and Prevention (CDC), vaccine efficacy rates are less than 30% against H3N2.

5 mice per cohort; CB-012 dosed 4 hours prior to infection, Tamiflu dosed 8 hours post infection

Influenza Virus

Influenza, or flu, is a respiratory infection caused by influenza viruses. The flu virus can cause mild to severe illness, and at times can lead to death. Young children, the elderly (> 65 years), pregnant women and immunocompromised patients are more prone to infection, but even healthy people are at risk of infection with seasonal flu. The CDC estimates that as many as 646,000 people may die from influenza each year worldwide.

In the U.S., the CDC estimated that during the 2017-18 flu season almost 50 million people became ill from the flu, resulting in approximately one million hospitalizations and $10.4 billion per year in direct medical expenses and an additional $16.3 billion per year in lost earnings. The CDC also estimated that almost 80,000 people died during the 2017-18 flu season, which makes it one of the most severe in recent history.

Prevention: The only preventive measure to protect against flu is the seasonal vaccine. However, in recent years the efficacy of the vaccine has been significantly variable, with effectiveness reported by the CDC of only 40% on average, depending on the virus strain and age of the recipient. In years when the seasonal vaccine results in sub-optimal protection, more patients are at higher risk for serious complications resulting from influenza. Vulnerable patient populations must then rely upon therapeutic options.

Treatment: Older antiviral medications, such as amantadine and rimantadine, are no longer recommended for use because of high levels of resistance. Currently, four therapeutic options for treating influenza are recommended by the CDC:

  • Oseltamivir phosphate (Tamiflu®)
  • Zanamivir (Relenza®)
  • Peramivir (Rapivab®)
  • Baloxavir marboxil (Xofluza™)

The above list of small molecule antivirals includes neuraminidase inhibitors and the recently approved endonuclease inhibitor, baloxavir. All of these molecules have one or more of the following limitations: short half-life, high susceptibility to resistance, multi-dose regimens and dose route limitations.