Shionogi sues Hospira to block Doribax generic

Japanese pharma Shionogi has brought a lawsuit against Hospira Inc to keep it from marketing a generic version of Shionogi’s Doribax, alleging it infringes one of the company’s patents.

Doribax is an injectable antibiotic with the active ingredient doripenem.

According to its website, Shionogi’s patent for a crystal form of the drug, a pyrrolidylthiocarbapenem derivative, is due to expire on March 30, 2021. Shionogi licensed commercial rights to the drug to Peninsula Pharmaceuticals, a subsidiary of Johnson & Johnson.

Hospira filed an Abbreviated New Drug Application (ANDA) with the US Food and Drug Administration (FDA) in February this year seeking approval to commercially manufacture and sell a generic version of the drug in the US before expiration of Shionogi’s patent.

According to Shionogi’s complaint made to the US District Court for the District of New Jersey on April 12, Hospira’s generic will be prescribed and administered in the “same or substantially similar manner” as Doribax, and therefore constitutes infringement “either literally or under the doctrine of equivalents.”

Hospira’s ANDA notice letter holds that Shionogi’s patent is “invalid” and “unenforceable”.

William Baton, a partner at Saul Ewing LLP, said the lawsuit appears to be an ANDA case brought under the Hatch-Waxman Act, a statutory scheme that encompasses generic company challenges to brand company patents.

He said that generally, under the act, if the generic is the first to file an ANDA for the particular generic drug, it will be granted 180 days of market exclusivity to launch its product.

If Hospira is successful in its challenge, the timing of its ability to launch could depend on a range of factors, including whether another generic has already secured 180 days of market exclusivity, or whether Hospira wishes to wait until any appeals against the case ruling have been resolved, he adds.

He said that in cases concerning brands and generics the generic could claim that the proposed product does not infringe the brand’s patent because it achieves its intended result in a different way, or that the patent in question is invalid because of its obviousness, indefiniteness or lack of utility.

Infringement must be proven by a preponderance of evidence, while invalidity must be proven by clear and convincing evidence, which is a higher burden of proof, he said.

Shionogi filed a patent infringement case at the US District Court for the District of New Jersey against Novartis subsidiary Sandoz relating to the same drug in December 2012.