Pfizer Prevailed in Pregabalin 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 in 2015.

 

Furthermore, in June 2017, the Seoul Central District court awarded Pfizer damage compensations for pregabalin patent infringement. However, the Korean Court did not grant injunction against Korean companies who sell generic products with off-labels.

 

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, the Supreme Court, however, maintained the patent by rejecting non-obviousness challenge.

 

After validity challenge was failed, Korean generic companies restricted indications of their label only to anti-convulgent. They carved out pain killing use from their labels.

 

The patentee argued that the change of label is not enough to avoid patent infringement liability because the sale of generic drugs has slightly dropped or never changed even after the carved-out pain treatment indication from the labels. Accordingly, the generic companies shall be liable for the patent infringement of their continued sale after the label change.

 

The Seoul Central District Court did not agree with the patentee’s argument. The court held that the patent is directed to a second use invention and without indication of the claimed use, there is no patent infringement.

 

The Seoul Central District Court only awarded the patentee damage compensation based on the sale before the label change – carved-out claimed indication from the generic’s labels. Pfizer appealed to the Patent Court and the off-label case of pregabalin is still pending.