Background
Otsuka Pharmaceutical Co., Ltd. owns patents covering highly pure tolvaptan and methods for its synthesis that reduce impurities by limiting the amount of sodium borohydride used. Lupin Ltd. submitted an Abbreviated New Drug Application to market a generic version of Otsuka’s drug, JYNARQUE. Otsuka sued for infringement and the district court held that Lupin’s process did not infringe the patents and that the asserted claims of one patent were invalid for obviousness.
The court’s reasoning
The court reviewed the district court’s claim construction of the term amount and found no clear error in defining it as the amount present while the reaction is taking place until practical completion. The court determined that Otsuka failed to provide sufficient evidence that Lupin’s process reached practical completion before adding more than one molar equivalent of the hydrogenating agent. Regarding the expert witness, the court found that Otsuka forfeited its challenge to the expert’s qualifications by not objecting at trial. On the issue of obviousness, the court found no clear error in the district court’s conclusion that a person of ordinary skill in the art would have been motivated to modify the prior art reference Kondo to achieve the claimed invention.
What it means going forward
The decision confirms that generic manufacturers using a process with higher molar equivalents of hydrogenating agents may avoid infringement of Otsuka’s process patents, and it reinforces the requirement for timely objections to expert testimony admissibility in patent litigation.
Podcast (federal-narrative-summaries): Play in new window | Download