The UK High Court has held that a pharmaceutical product claimed only within a Markush formula and not expressly referred to in the patent was protected by the patent for the purposes of obtaining a Supplementary Protection Certificate (SPC).

Pakistan-based pharmaceutical company, Searle, was the owner of a European Patent which claimed a group of compounds described by a Markush formula, a method of formulating a claim directed to a group of similarly acting compounds. One compound contained within the Markush formula in the Patent was darunavir, a drug used in the treatment of HIV. The Patent expired in August 2013 but was extended to February 2019 by an SPC for darunavir. Global generics businesses, Sandoz and Hexal, challenged the darunavir SPC claiming that darunavir was not protected by the Patent. Darunavir was encompassed within the Markush formula but the Patent did not expressly disclose darunavir or refer to it by name. The issue was therefore whether a compound that is only identified within a Markush formula and not expressly identified in a patent is protected by a basic patent , pursuant to the SPC Regulations.

Applying principles set down by the Court of Justice of the European Union (CJEU) in the case of Eli Lilly v Human Genome Sciences and a proposed reformulation of the CJEU test put forward by the UK Court in Teva v Gilead, the Court held that it was sufficient for the Patent to identify the product’s active ingredient within a Markush formula. Accordingly, darunavir was indeed protected by a basic patent and the darunavir SPC was validly granted.

If Sandoz and Hexal’s contentions had been accepted, intellectual property offices examining SPCs would have been required to analyse patent claims to determine whether the relevant active ingredient was individually named or depicted within the basic patent. This would have added substantial complication to the SPC system. This decision will therefore be welcomed by most as clarifying what is protected by a basic patent for the purposes of obtaining an SPC.