A triple antiviral-drug regimen may be more effective than any single drug alone against 2009 pandemic influenza A(H1N1) as well as seasonal flu strains, based on results from preclinical, tissue-culture studies.
A clinical trial has launched to assess the safety and efficacy against all influenza type A infections of a specific combination of oseltamivir, amantadine, and ribavirin, Amy Patick, Ph.D., said during a press briefing at the annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy.
The tissue culture results suggest a synergistic antiviral interaction among the three agents that gives them an efficacy 5- to 20-fold higher than any of the three drugs alone or any combination of two of the drugs, said Dr. Patick, vice president for research at Adamas Pharmaceuticals Inc., in Emeryville, Calif. The results were reported at the meeting by Mark Prichard, Ph.D., a professor of pediatrics at the University of Alabama, Birmingham.
The three-drug combination, called Triple Combination Antiviral Drug (TCAD) therapy, is being developed by Adamas using proprietary formulations and dosages, Dr. Patick said.
Adamas had begun developing TCAD for treating influenza infections before the current H1N1 pandemic began, and the company says it believes the triple-drug combination will also be effective against seasonal strains of influenza A. Patients infected with any type of flu A infection will be enrolled in the two clinical studies, Dr. Patick said in an interview.
One study already underway in the Southern Hemisphere will enroll 250 immunocompromised patients, and will compare the efficacy and safety of TCAD against monotherapy with oseltamivir (Tamiflu). A second study that is planned to start soon in the United States, Canada, and Europe will also examine the efficacy and safety of TCAD in both immunocompromised and immunocompetent patients infected with influenza A.