Researchers develop first oral drug to treat smallpox...( the National Institute of Allergy and ...)

NIAID, USAMRIID and the Centers for Disease Control and Prevention (CDC) in Atlanta, oversee most of the countrys effort to develop antiviral therapies for smallpox. After screening hundreds of existing compounds for activity against smallpox while working in the CDCs Biosafety Level 4 (maximum containment) Laboratory in Atlanta, USAMRIID identified cidofovir as active against smallpox. The drug is currently used to treat retinal infections caused by cytomegalovirus.

"Cidofovirs drawback is poor oral bioavailability. It can only be given intravenously," Hostetler said. "If youve got thousands of people exposed to smallpox, a drug that needs to be injected would be difficult to use widely."

If continuing studies support HDP-CDVs effectiveness and safety, the drug could be given in pill or capsule form over 5 to 14 days for the prevention and treatment of smallpox in persons exposed to the disease, Hostetler said.

The Huggins group from USAMRIID announced at the 15th International Conference on Antiviral Research that HDP-CDV was effective in blocking the replication of several strains of smallpox in tissue culture. Surprisingly, the HDP-CDV compound was 100 times more active than cidofovir in slowing smallpox reproduction.

Also presented at the conference were Huggins results of HDP-CDV therapy in mice infected with cowpox, a poxvirus closely related to smallpox. Working in collaboration with Hostetlers group, Huggins and coworkers at USAMRIID found that 5 daily oral doses of HDP-CDV given after infection prevented death from cowpox infection.

The Huggins group also found that virus levels in the lungs of infected animals was reduced to nearly undetectable levels by oral administration of HDP-CDV, but not by intravenous administration of comparable amounts of cidofovir.

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Contact: Cindy Butler
Cynthia.butler@med.va.gov
858-552-4373
VA Research Communications Service
20-Mar-2002