Obviousness Versus Obviousness-Type Double Patenting

In Prometheus Laboratories, Inc. v. Roxane Laboratories, Inc., the Federal Circuit affirmed the district court's finding that Prometheus' claims were invalid as obvious, but in so doing it cited its own precedent regarding obviousness-type double patenting. Is the court blurring the line between these doctrines?

The Product At Issue

The product at issue was Roxane's generic version of Prometheus' Lotronex® (alosetron HCl) product, which was approved by the FDA for the treatment of irritable bowel syndrome (IBS). As explained by the Federal Circuit, IBS is a condition defined and diagnosed by its collection of symptoms. These symptoms may contribute to diarrhea-predominant IBS ("IBS-D"), constipation-predominant IBS ("IBS-C"), or some combination. Lotronex® first was launched in 2000, but was removed from the market after being linked with severe side effects. It was re-launched in 2002 with a more restrictive label, i.e., indicated only for women with severe IBS-D who have, inter alia, chronic symptoms generally lasting six months or longer, and not for use in patients with constipation.

In 2009, Roxane filed an ANDA seeking approval of its generic version of Lotronex® which included a paragraph IV certification against the Orange Book listed patent, U.S. Patent No. 6,284,770.

The Patent at Issue

The '770 patent is directed to "[m]edicaments for the treatment of non-constipated female irritable bowel syndrome," and includes claims that correspond to the approved use of Lotronex®. The patent issued in 2001, and Prometheus sought reexamination of the patent in 2009. A reexamination certificate issued on October 19, 2010, with the following claims amended or added during reexamination:

5. A method for treating a diarrhea-predominant female IBS patient, while excluding those with predominant constipation, said method comprising: assessing whether said diarrhea-predominant female IBS patient has experienced symptoms for at least six months; and administering an effective amount of alosetron or a pharmaceutically acceptable derivative thereof to said patient who has experienced symptoms for at least six months, wherein said effective amount is dependent on the condition of the patient and is at the discretion of the attendant physician.

10. The method for treating according to claim 5, further comprising assessing whether said female IBS patient has experienced at least moderate pain prior to administration of alosetron.

13. A method for treating...