GlaxoSmithKline is facing a double patent loss in the UK following court challenges to its two biggest selling brands, Seretide and Seroxat.

The company lost a High Court challenge to its patent on antidepressant Seroxat (paroxetine) in December to generic manufacturer Apotex, potentially robbing GSK of revenues from its second biggest selling product in the UK.

An appeal has been filed by GSK and will be heard on the 22 or 23 of March, but Apotex has pre-empted the court decision and has already launched its own version of the drug.  

But even worse news could be round the corner for GSK in its home territory, with a second challenge pending on its biggest seller, combination inhaler product Seretide.

A number of generic companies including Cipla and Neolab brought a court case last year seeking the revocation of GSK patent covering the combining of salmeterol and fluticasone propionate into one inhaler. The companies are challenging the patent on grounds of obviousness, citing Ventide, a precursor asthma product which combined Ventolin and Becotide.

The trial ended in January and the judge is expected to rule within days of the Seroxat decision, making March potentially one of the most costly ever for the UK company if both decisions go against it.

GlaxoSmithKline UK says it is confident of winning the Seretide case, a spokesman commenting: "We will rigorously defend our patents - we believe that this is one is valid."

Even if GSK lose the case, the generics manufacturers will have to wait until 2005 before they can launch versions of the combination. This is when patents covering the individual drugs will expire, and the companies would have to devise their own delivery methods as GSK patents on the dry powder Diskhaler and metered dose inhaler run until 2011 and 2012 respectively.

Seretide is GSK's biggest brand worldwide, with sales of $3,631 million ( £1,877m) in 2003, a rise of 39%.  The brand is also GSK biggest seller in the UK, earning sales in England in 2002 of £88 million, making it the sixth biggest earning product in the country. If the company does lose both the Seroxat and Seretide patent battles it would seriously UK sales, at a time when it has few new blockbuster candidates in its late-stage pipeline.

But the UK patents are a footnote compared to the massive blow to revenues inflicted by US patent losses over the last two years. Chief executive Jean-Pierre Garnier has warned that 2004 will be  "year of transition" for GSK as it continues to absorb huge reductions to its revenues after losing US patents on Seroxat and Wellbutrin in 2003. The company has succeeded in softening the impact by launching new patent-protected sustained release versions of the drugs in the US.

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Friday, February 13, 2004