Officials of the Australian drug maker Biota Holdings Ltd. said a Phase II clinical trial of an antiviral treated colds in people with asthma. Peter Cook, chief executive officer of Biota, said the successful completion of the Phase II trial delivered a major milestone in the development of BTA798, or vapendavir, for the treatment of naturally acquired human rhinovirus -- the predominant cause of the common cold -- infection in asthmatics. Drug treatment resulted in a statistically significant reduction in cold symptoms compared to a placebo, Cook said. Cook said the next phase is to design appropriate Phase III studies. The Phase II multicenter, randomized, double-blind, placebo-controlled study in asthmatic adults with symptomatic, naturally acquired human rhinovirus infection was conducted over two consecutive seasons in 48 centers in the United States. Subjects received either 400 milligrams of BTA798 or placebo twice daily for six days. "This trial not only represents a valuable step in the successful delivery of one of Biota's key programs but it is also a unique accomplishment in the field of antiviral development," Cook said in a statement. "While the clinical link between human rhinovirus infection and loss of asthma control is now widely accepted, Biota is the first company to evaluate the use of an anti-viral to treat the infection in asthmatics. This has the potential to be of considerable benefit to sufferers through better control of their asthma."