Pirfenidone – USA

Pirfenidone – USA

On Dec. 22, 2022, Federal Circuit affirmed district court’s decision of non-infringement and invalidity.

 

Genentech, Inc. and InterMune, Inc. (Plaintiffs) sued Sandoz and Lek pharma (Defendants) for infringement as later submitted ANDA to market generic version of Esbriet® (Pirfenidone) tablet. Pirfenidone is a drug used to treat idiopathic pulmonary fibrosis (“IPF”). The asserted patents (LFT and DDI) claim methods for managing certain side effects when using pirfenidone to treat IPF. After trial, district court held that the LFT patents are obvious and defendants did not induce infringement while DDI patents are not directly infringed. You can read the decision summary “here” on this blog.

 

During appeal, Federal Circuit found no clear error and sided with district court. With respect to LFT patents, court said that varying doses in response to the occurrence of side effects would seem to be a well-established, hence obvious, practice. Thus, claiming it as an invention would appear to be at best a long shot. District court correctly found that the specific dose modifications claimed in the LFT patents would have been obvious over the disclosures in Azuma and the Pirespa® label, combined with well-known standard medical practices. Contrary to Genentech’s assertion, the district court’s interpretation of Azuma and the Pirespa® label also relied on extensive record evidence. That evidence illustrated that standard medical practice at the time was not to discontinue medical treatment with pirfenidone or other drugs for patients experiencing Grade 2 liver enzyme elevations. With respect to the objective indicia of nonobviousness, the district court properly found Genentech’s evidence unpersuasive. Therefore, the asserted claims in the LFT patents would have been obvious over the cited prior arts.

 

With respect to DDI patents, court said that Genentech failed to identify any legal error or clear factual error in the district court’s direct infringement analysis. Sandoz presented evidence of how pirfenidone would be prescribed in practice, including testimony from physicians that, in their decades of treating IPF patients, they had never prescribed pirfenidone to an IPF patient taking fluvoxamine; and were they to find themselves in that position,
they would choose a noninfringing response—i.e., prescribing nintedanib instead. Even if the FDA had been concerned about the possibility that a patient may be treated with both pirfenidone and fluvoxamine, that does not establish by a preponderance of the evidence that if Sandoz’s drug “were put on the market, it would infringe” the asserted DDI claims. Therefore, Genentech had not met its burden to show that Sandoz’s ANDA product would directly infringe the asserted claims of the DDI patents which require use of both pirfenidone and fluvoxamine.

 

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