BMS sued Korean pharmaceutical companies alleging patent infringement of entecavir compound patent and low dose formulation patent

Baraclude tablets are a blockbuster drug of BMS that has been sold for the treatment of chronic hepatitis B virus infection in Korea. BMS listed 2 patents in Green List of KFDA that is a local version of the Orange Book of US FDA. Entecavir compound is the active ingredient of Baraclude.

Korean generic companies obtained MA for generic versions to Baraclude and are ready to launch their generic products to the local market. BMS filed patent infringement lawsuits against Korean pharmaceutical companies recently.

Before BMS patent infringement lawsuits, local companies filed invalidity trials to challenge the validity of the corresponding Korean entecavir compound patent. Also, they filed trials to confirm the scope of patent right about the corresponding Korean low dose formulation patent. The invalidity case of the compound patent is pending in the IPT of KIPO. But the IPT decided that generic products do not infringe the scope of the low dose formulation patent. In appeal, the Patent Court upheld the IPT decision that low dose entecavir formulations of 0.5mg or 1.0 mg should be regarded being obvious over the prior art and that generic drug do not infringe the subject patent.

Korea has the bifurcated system that allocates decision power to separate authorities. Patent infringement issue and patent invalidity issue must be decided by two separate and independent courts. Patent infringement and invalidity challenge may occur simultaneously but two proceedings are correlated.

In the patent infringement lawsuits, defendants Korean companies will raise an affirmative defense about invalidity of entecavir compound patent. Such invalidity defense is allowed and the court may stay the infringement lawsuit proceeding on its discretion until the IPT of KIPO decides validity issue.

On the other hand, defendants are quite safe from patent infringement liability of low dose formulation patent because they had prior decisions from the IPT and the Patent Court that their products are out of the scope of the patent claims in issue.