The UK Patents Court has found that GSK's patent for the anti-malarial drug Malarone (EP(UK) No. 0670719) is invalid. Malaria is one of the most prevalent tropical diseases, and Malarone is the most successful anti-malarial prophylactic in the UK. Malarone contains a combination of the compounds atovaquone and proguanil in the ratio 5:2.

Revocation of the patent was sought by two companies, Glenmark and Mylan, who intend to sell generic versions of Malarone in the UK. There was no dispute that the generic versions of Malarone fall within the scope of the patent.

The patent was challenged on the sole ground of obviousness in view of two pieces of prior art, namely a presentation by one of the inventors of the Malarone patent, and an abstract relating to a lecture. The difference between claim 1 of the patent and the disclosure of the presentation was the 5:2 ratio of the compounds. Although this feature was acknowledged by both sides to confer novelty, it did not in itself provide a technical effect that rendered the claimed subject matter inventive. As such, the question was considered as to whether it would have been obvious from the prior art to develop the combination of atovaquone and proguanil.

The prior art presentation described a preliminary trial in patients with malaria which demonstrated successful results with a combination of atovaquone and proguanil. The Patentee argued, inter alia, that the nature of the trial and results, and the commercial environment at the priority date, would have dissuaded a skilled team from pursuing the claimed combination. However, Mr Justice Arnold disagreed, and found that a skilled team would not have concluded from the disclosures of the presentation that the combination of atovaquone and proguanil was not worth pursuing. It was also found that the prior art lecture abstract would not lead the skilled team to the conclusion that the claimed combination should not be pursued.

Claim 1 was therefore found to be obvious in view of the prior art. Claim 9 directed to a pharmaceutical composition comprising the claimed combination in association with one or more pharmaceutically acceptable carriers was also found obvious and invalid for similar reasons.

As such, the patent was found invalid and revoked.

The full judgement can be found by clicking here.