On June 30 2017 Pfizer successfully enforced its patent covering a secondary use of its Lyrica product (active ingredient pregabalin) against 13 generic drug manufacturers in South Korea, and was awarded a total of approximately KRW2.2 billion (approximately $2 million) in damages.(1)
Pregabalin was originally developed to treat epilepsy, but was later discovered also to relieve pain (eg, neuropathic pain and fibromyalgia). Pfizer's subsidiary, Warner-Lambert, obtained a second medical use patent to cover the use for pain treatment. Pfizer Korea obtained an exclusive licence to the patent from Warner-Lambert and an approval for the Lyrica product in 2005 for the treatment of:
- neuropathic pain; and
After its launch, Lyrica became very successful, achieving annual sales of several million dollars in South Korea. Over 90% of prescriptions for Lyrica are for the treatment of pain, while the proportion of prescriptions for epilepsy treatment is relatively insignificant.
Many generic drug manufacturers sought to sell Lyrica in South Korea and filed invalidation actions against the patent, beginning in 2011. Subsequently, the generic drug manufacturers began to sell and market generic versions of Lyrica in 2012, before the patent expiration. In 2016, after five years of litigation, the Supreme Court confirmed the validity of the patent. Warner-Lambert and Pfizer Korea (collectively Pfizer) then pursued patent infringement and damages actions against selected generic drug manufacturers. In the meantime, the defendants obtained their generic Lyrica approvals with indications for both pain and epilepsy treatments, although they later removed the pain indication from their product approvals.
In the infringement and damages actions, the defendants argued that:
- the patent could not be enforced because of invalidity;
- there was no infringement after the patented pain indications were deleted from their product approvals; and
- the damages amounts alleged by Pfizer were unreasonable.
One of the defendants filed another invalidation action for failure to meet the description requirements one day before the Supreme Court decision concerning the first invalidation action was issued.
Regarding invalidity, the district court rejected the generic manufacturers' arguments for lack of data supporting the pharmacological effect. It acknowledged the validity of the patent on the grounds that the specification sufficiently disclosed the pharmaceutical effects of treating neuropathic pain and fibromyalgia; thus, it sufficiently met the description requirements for pharmacological data as a medical use invention.
Regarding infringement, the court found the manufacture and sale of generic drugs before the deletion of pain indication from the defendants' product approvals constituted infringement.
Further, regarding the damages amounts, the district court granted approximately 72% of the total amount of damages claimed by Pfizer. Proving actual damages was difficult because the defendants did not produce any sales or profit data. As such, the court awarded damages amounts in accordance with Article 128(7) of the Patent Act (covering calculation of damages where patent infringement is confirmed but the damages amount is difficult to prove), after considering all of the arguments and evidence. In this regard, the court asked the Health Insurance Review and Assessment Service to produce data concerning doctors' prescriptions of generic drugs for the treatment of pain and calculated the total amount based on this information. In doing so, the court also included in its damages calculation some of the prescriptions that were issued after the pain indications were deleted from the generic product approvals, noting that those prescribed generic products had been manufactured while the pain indications were included in the product approvals.
This is the first decision in South Korea in which a court has awarded damages for infringement by generic drug manufacturers of a second medical use patent.
This article was first published by the International Law Office, a premium online legal update service for major companies and law firms worldwide. Register for a free subscription.
For further information on this topic please contact Yu-Seog Won, Young Kim or In Hwan Kim at Kim & Chang by telephone (+822 3703 1114) or email (firstname.lastname@example.org, email@example.com or firstname.lastname@example.org). The Kim & Chang website can be accessed at www.kimchang.com.