The ‘770 patent which is owned by Prometheus Laboratories Inc., claims a method of treatment for IBS-D utilizing alosetron. Prometheus also has the ‘800 patent which covers the use of ‘770 patent.

In 2009, Roxane filed an abbreviated new drug application (ANDA) with FDA seeking approval of a version of Lotronex, since the ‘770 patent expired. In 2010, reexamined ‘770 patent was relisted in the Orange Book and Roxane submitted a paragraph 4 certification to the FDA.

In 2011, Prometheus sued all the defendants alleging infringement of ‘770 patent. Prometheus alleged that Roxane’s label would encourage doctors to prescribe alosetron in a sense that infringes the claims.

The district court held that “the elements of the ’770 patent were present in the prior art, and the differences between the prior art and the claims of the ’770 patent are insubstantial . . . [as] some of the prior art is virtually identical to the claimed inventions”. In addition, the district court also held that “the claims were invalid for obviousness-type double patenting in light of the claims of the ’800 patent”. So, the district court did not agree with Prometheus, saying that there is no issue of infringement. Then, Prometheus appealed.

According to the Federal Circuit, obviousness is based on “underlying factual findings, including: (1) the level of ordinary skill in the art; (2) the scope and content of the prior art; (3) the differences between the claims and the prior art; and (4) secondary considerations of nonobviousness, such as commercial success, long-felt but unmet needs, failure of others, and unexpected results”. And, also states that a patent would have been obvious if the differnces between the calimed invention and prior art are such certain that a person having ordinary skill in the art will distinguish them. The Federal Circuit held that “even treating the limitations of the ’770 claims as exclusions, we conclude that before October 7, 1997, it would have been obvious to a person of ordinary skill to treat those sub-species claimed here”. Prometheus objected.

The Federal Circuit noted that “if the later expiring patent is merely an obvious variation of an invention disclosed and claimed in the reference patent, the later expiring patent is invalid”. The court also stated that in this case, it would have been obvious to a person who has ordinary skill in art to read the ‘800 patent and treat patients with IBS-D. Therefore, the Federal Circuit affirmed the district court’s decision noting that “the challenged claims of the ’770 patent would have been obvious over the ’800 patent and other prior art”.

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