Advocate general confirms Dutch Court of Appeal's Cipralex decision

Over the past few years Lundbeck’s patents protecting its blockbuster drug Cipralex® have been subject to invalidation actions around the world. Cipralex is an anti-depressant drug containing the active substance escitalopram, the (S)-enantiomer of the racemic mixture marketed as, among other things, Cipramil®.

Cipramil was protected in the Netherlands by Patent 192.451 C, filed in 1977, and Supplementary Protection Certificate (SPC) 970031, which expired in 2002. In 1989 Lundbeck filed a European patent (EP) application seeking patent protection of Cipralex. This patent application was eventually granted as EP 347.066 B1, which expired in 2009. The corresponding SPC 300155 will expire in 2014. Therefore, Lundbeck has had protection for the same drug for more than 35 years.

The validity of EP 347.066 B1 and SPC 300155 has been litigated in the Netherlands since 2008. EP 347.066 B1 has two independent claims:

• Claim 1, directed at the Cipralex product itself.
• Claim 6, directed at a method for the stereoselective synthesis of Cipralex.

In 2009 the Dutch Patents Court decided that Claims 1 and 6 were invalid. The court held that:

• Claim 1 was novel, but lacked inventive step (over established case law of the European Patent Office).
• Claim 6 was obvious and not inventive over Lundbeck’s US Patent 4,650,884 in combination with common general knowledge.

Lundbeck appealed. In January 2012 the Dutch Court of Appeal partly overruled the decision of the Dutch Patents Court. It confirmed that Claim 1 was novel but not inventive. However, Claim 6 was considered to be non-obvious and valid. In regard to the SPC, the Dutch Board of Appeal decided that it was valid insofar as it was based on the product as obtained by the process set out by Claim 6. Accordingly, Cipralex made by other methods would not infringe the SPC.

In February 2012 Lundbeck filed an appeal at the Dutch Supreme Court; the oral hearing took place in November 2012. On 8th March 2013 the advocate general issued his opinion, confirming the decision of the Dutch Court of Appeal. The Supreme Court's final decision is expected in June 2013.