Pfizer’s Victory in Lyrica® Patent Infringement Lawsuit in Korea

Based on Pfizer’s Lyrica patent, Korean courts granted preliminary injunctions for patent infringement against two Korean pharmaceutical companies. The local companies launched a generic version of Lyrica last year. The active ingredient of Lyrica is pregabalin that is a known chemical compound and a derivative of GABA (gamma-aminobutyirc acid). Further, the pharmacological effect of pregabalin is known as a depressive neurotransmitter and has been sold as an anti-convulgent drug for a long time. Pfizer discovered a new medicinal use of pregabalin. The subject Korean Patent No. 491282 is directed to a new use of pregabalin for treating pain. It is a second use invention that is one of the main indications of Lyrica.

Korean companies challenged validity of the subject patent on the ground that the new use of pregabalin for treating pain can be anticipated or is obvious over the prior art. They alleged that the pain killing effect might be in the scope of anticipation of an ordinary skilled person because the prior art discloses the compound and its neurotransmitter depressing effect. Also, the blocking of certain neurotransmitter flow may be correlated with anti-pain effect. The IPT of KIPO and the Patent Court, however, maintained the patent by rejecting non-obviousness challenge. The invalidity proceeding has been reviewed by a separate authority rather than a civil court under bifurcation system and is pending before the Supreme Court as a final stage now.

In the meantime, the patentee brought lawsuit for seeking preliminary injunctions against generic companies before the Seoul Central District Court. Recently Pfizer won the cases and was successful in blocking selling generic version of Lyrica in Korea.