Biotech company Aviron ( AVIR) said Monday it is confident it won't have to conduct additional clinical trials for its flu vaccine before getting the treatment approved, based on feedback from the Food and Drug Administration. On Friday, the FDA sent Aviron a "complete review letter," which detailed the steps required to get the experimental FluMist nasal spray vaccine approved. Aviron said Monday that the FDA has "requested additional information and clarification regarding clinical and manufacturing data" to support FluMist's application. Aviron added that it still needs to clarify some of the FDA's requests, and the company did not predict how long it will take to respond to the FDA's questions, or how long regulators will take to review the new information. But Aviron should be able to get FluMist to market in time for the 2002-2003 flu season. If it does, it will be one year behind schedule. Hopes to have the vaccine ready this year were dashed on July 27, when an FDA advisory panel did not recommend the drug's approval because of safety concerns, despite finding FluMist effective. If the FDA had asked Aviron to conduct more tests, FluMist could have been delayed even further. Monday's announcement should provide some support for Aviron shares, which have lost half their value since the July 27 setback. Aviron closed Friday at $22.39 per share. If approved, FluMist would be the first flu vaccine taken as a nasal spray by healthy adults and children. The drug will be co-marketed by American Home Products ( AHP).