Chimerix

Smallpox

CMX001 is in development as a biodefense countermeasure in the event of a smallpox release.

An acute, highly contagious disease caused by variola virus, a member of the orthopoxvirus family, smallpox is a disease of significant interest to government agencies because of concerns that the virus could be used for bioterrorism.

In vivo, the antiviral activity of CMX001 has been characterized in mice infected with ectromelia, vaccinia, and cowpox viruses and in rabbits infected with rabbitpox. In each model, a dose of CMX001 was identified that provided protection against challenge with a lethal viral inoculum. Higher oxidative metabolism of CMX001 in monkeys necessitates efficacy trials in this species with cidofovir and extrapolation of human doses for CMX001 through the active antiviral cidofovir diphosphate. Since cidofovir and CMX001 produce the same active antiviral species in vivo (cidofovir diphosphate), it can be used as a product surrogate for CMX001 to test activity in monkeys. Cidofovir has provided protection in lethal models of monkeypox and variola (smallpox) infection in non-human primates. Animal studies with CMX001 for treating smallpox under the Animal Efficacy Rule are proceeding.

Our ongoing work to develop CMX001 for smallpox is partially funded by a $36.1 million grant awarded to the company by the National Institute of Allergy and Infectious Diseases.