U.S. working to ready more flu drugs, vaccine

WASHINGTON (Reuters) - A top U.S. health official said on Wednesday new influenza drugs could be approved within days for people critically ill with swine flu and assured Congress that H1N1 vaccine production problems have been overcome.

Health and Human Services Secretary Kathleen Sebelius said government scientists would soon decide whether to approve the intravenous use of experimental drugs for people too sick to take existing antiviral medications by either pill or inhaler.

"It is imminent," she said at a hearing before the Senate Homeland Security and Governmental Affairs Committee. Asked by the panel's chairman, Senator Joe Lieberman, if a decision could come within days, Sebelius replied: "We hope that's the case."

Two antiviral drugs are recommended for flu: Tamiflu, known generically as oseltamivir and marketed under license from Gilead Sciences Inc by Roche Holding AG; and Relenza, known generically as zanamivir and made by GlaxoSmithKline Plc under license from Australia's Biota Inc.

Lieberman urged Sebelius to ensure that enough intravenous antivirals were available, citing estimates from White House science advisers that 150,000 to 300,000 Americans could require hospitalization in intensive care units because of H1N1.

"There could be a lot of people looking for the IV antiviral," he said.

Because influenza viruses mutate so quickly, health officials are keen for new drugs and several are in the works.

Furthest along in the pipeline is Biocryst Pharmaceuticals Inc's and Shionogi & Co's peramivir.

BioCryst has said it was starting two late-stage trials testing the intravenous formulation of peramivir to treat hospitalized patients with serious influenza.

GOVERNMENT CONTRACTS

In 2007, BioCryst was awarded a $102.6 million, four-year contract from HHS to develop peramivir for the treatment of influenza. Last month it got another $77.2 million from the department to complete late-stage development.

Relenza, an inhaled drug, can also be formulated for intravenous use.

Lieberman also expressed concern about a delay in H1N1 vaccine production that prompted the U.S. Centers for Disease Control and Prevention last week to cut its supply estimates to 28 million to 30 million from 40 million doses for October.

"H1N1 is so contagious it may well be getting ahead of our ability, public health's ability, to respond to it," he said.

But Sebelius said manufacturers had overcome two problems: unexpectedly low dose yields from chicken eggs used to produce the vaccine and glitches in new production lines.

"Those two issues have been corrected," she said. "We're hoping by early November that they will be back on the track for the number of vaccination doses per week that we had originally anticipated."

The flu vaccine is made using old technology that involves growing the virus in chicken eggs, and it takes months to make a new formulation to match circulating flu strains.

For the current season, the U.S. government has ordered up to 250 million doses of H1N1 vaccine from five companies: AstraZeneca, Sanofi-Pasteur, Novartis AG, GlaxoSmithKline and CSL.

(Editing by Maggie Fox and Eric Beech)