GlaxoSmithKline has decided to sell the US rights to the antidepressant Wellbutrin XL to Canada’s Biovail Corp for £340 million.

The drugs giant has been distributing Wellbutrin XL (bupropion), which was developed by Biovail, in the USA since September 2003, and sales of the drug for the first quarter across the Atlantic reached £45 million. However that was 70% down on the like, year-earlier period and Wellbutrin XL has had to compete with generics since the second quarter of 2008 for the 150mg tablet and since the end of 2006 for the 300mg form.

GSK will retain its existing rights to the antidepressant for countries outside the USA, excluding Canada. Non-US sales of the product reached just £7 million in the first quarter of 2009. The company said it expects to record a pretax gain of £340 million and says the combined total of other operating income and profits on disposals to be around £700 million in 2009.

Deirdre Connelly, president of North American Pharmaceuticals at GSK, said that “we are actively reshaping our US business and managing the transition occurring in our product portfolio”. She added that the deal with Biovail is “one of a series of actions we are taking to maximise the value of our current assets and to enable us to resource and invest in new products and upcoming launches”.

Relenza production ramped up
Meantime, GSK has confirmed in the last few days that it has increased production of its influenza drug Relenza (zanamivir) in response to the outbreak of swine flu (H1N1).

The company will produce five million treatment packs of Relenza a month within the next 12 to 14 weeks, noting that it currently had six million packs of the drug in stock. Of that, GSK says it has prioritised orders to governments “and is working with them to determine the best mechanisms for distribution of Relenza either through public or commercial routes”.

To further expand production, the company noted that it is in “active discussions with several other companies to increase manufacturing capacity of the product”. It is working with China's Simcere Pharmaceuticals, which was granted a voluntary licence in 2006 to manufacture and sell products containing zanamivir in China and all 50 of the world's least-developed countries.

GSK added that it “stands ready to begin manufacture of a potential vaccine against the new influenza A (H1N1) strain virus once the World Health Organisation and other public health authorities make recommendations for composition of the vaccine”.