Zanamivir (Glaxo Wellcome)

Zanamivir, a neuraminidase inhibitor under license from Biota, has been developed and launched by Glaxo Wellcome for the treatment of influenza virus infection [277127]. While registered as drugs, neuraminidase inhibitors are technically vaccines as they are believed to work by provoking an immune response, thus preventing the spread of infection from one cell to another within the respiratory tract [314356]. It is administered, using an inhaler, directly to where the virus replicates, minimizing the potential for side effects. Zanamivir has been launched, under the name Relenza, for the treatment of influenza in Australia [325148], New Zealand [335591] and the UK [341871]. It is registered in Mexico and Armenia [346474], and approved in Japan [351580]. In October 1999, it was launched in the US [352392] and Glaxo confirmed in January 2000, that zanamivir has been launched all over Europe, with the exception of Greece and Spain, where launch is imminent [352513]. In October 1999, the British Pharma Group (BPG) wrote to the UK Prime Minister to seek a discussion on the implications for the British-based pharmaceutical industry of the recommendation from NICE's Raised Appraisal Committee that Relenza should be banned from the NHS [342597]. An FDA submission was made in October 1998 [302732,304779]; the FDA advisory committee met on February 24 1999 to discuss the application [313583]. The Antivirals Drugs Advisory Committee voted against recommending zanamivir for FDA approval [316196]. Members suggested that additional studies using a different endpoint or targeting specific high-risk populations would be more likely to garner support [317454]. Following a discussion with Glaxo Wellcome in April 1999, the FDA indicated that it would continue to review the NDA for zanamivir [320565]. In July 1999, the company received final FDA approval for the drug for the treatment of both influenza A and B [334127], and aimed to initiate a phase IV trial program for the detection of consumer problems with the product, following launch of the product in time for the 1999-2000 flu season [352392,335048]. In September 1998, Glaxo applied to the Canadian Health Protection Branch (HPB) for approval to market zanamivir for the treatment and prevention of influenza. A separate application for Fast Track approval was also made with the HPB [299375,299472]. In November 1999, zanamivir received approval in Canada [346474]. Glaxo expects to make MAA and NDA filings for the use of zanamivir as a prophylactic in 1999 [333494]. In July 1998, Merrill Lynch predicted that as zanamivir offered only modest benefits gained from a narrow treatment window, potential would be limited and forecast annual sales of US dollar 30 million [302048]. In January 1999, Paribas predicted sales of pounds 75 million in 1999, rising to pounds 280 million in 2003 [317650]. In April 1999, ABN Amro predicted sales of pounds 23 million in 1999, rising to pounds 326 million in 2003 [328676]. In August 1999, Lehman Brothers estimated that sales of zanamivir will reach US dollar 400 million by 2003, and that it is an obvious candidate for an OTC switch, although this is not likely until 5 years after launch [336356].