US biotechnology company, BioCryst Pharmaceuticals, has restarted testing of an influenza drug - dropped two years ago because of poor efficacy - amid current fears about a new flu pandemic.

BioCryst stopped developing peramivir - a neuraminidase inhibitor in the same drug class as Roche’s Tamiflu (oseltamivir) and GlaxoSmithKline’s Relenza (zanamivir) - after its oral formulation was found to have poor bioavailability in trials. Partner Johnson & Johnson exited the collaboration to develop the drug, and its prospects looked bleak.

But as fears grow about a new pandemic, studies have suggested that older flu drugs such as amantadine and rimantidine - once the mainstay of any country’s flu preparedness strategy - are likely to be ineffective in treating the avian flu strains expected to cause the next flu pandemic. Meanwhile, Roche and GSK are struggling to meet the demand of governments seeking to stockpile their products, so BioCryst has been prompted to re-open the dossier on peramivir, which is claimed to be more potent against avian flu strains than the other neuraminidase inhibitors.

The company has started testing an injectable formulation of the drug, which should bypass the oral bioavailability issue, in the hope of being able to offer the drug to governments that cannot meet their quotas for approved antiviral drugs. There is already a well-established precedent for the supply of experimental drugs in emergencies; the US government has already placed major orders for developmental flu vaccines in anticipation of a new pandemic [[16/09/05a]].

The company’s chief executive, Charles Bugg, told the UBS at the end of September that BioCryst is gearing up to file for approval to start clinical testing of the parenteral formulation of peramivir before the end of the year. It is also planning to start Phase II tests in Southeast Asia in conjunction with the US National Institutes of Health.