It is generally obvious to treat a limited subset of patients with an otherwise known procedure when there are no unexpected results directly attributable to the patient subset itself. Here, for example, limiting the patient pool for a drug treating irritable bowel syndrome (“IBS”) was found to be insufficient to avoid a finding of obviousness because the limitations were merely directed to a known type of IBS, to treating the gender that predominantly experiences IBS, to treating patients with a characteristic that is always or almost always evaluated in establishing IBS, and to assessing symptoms for a duration of time that was common in diagnosing patients with IBS. This would be a good case to consult before responding to an obviousness rejection of a particular species that is predicated on the prior art’s disclosure of the genus.
Background / Facts: The patent being asserted here is directed to a method of treatment for diarrhea-predominant irritable bowel syndrome (“IBS-D”) utilizing alosetron (known by the brand name Lotronex). The prior art discloses the general use of alosetron to treat patients suffering from IBS. The patent here claims treating a subset of those IBS patients—those who (1) are women (2) with IBS-D (3) who have experienced symptoms for at least six months and (4) who have had moderate pain.
Issue(s): Whether it would have been obvious to a person of ordinary skill to treat the sub-species claimed here.
Holding(s): Yes. While recognizing that “[a]n obviousness rejection likely would not be appropriate where the new patient subset displayed unexpected results,” the court ultimately concluded that “it would have been obvious for a person skilled in the art to have separately treated the limited subset claimed in the [] patent with alosetron, and that any unexpected results were attributable to factors exogenous to the [] patent. … [T]hese limitations are directed to a known type of IBS, to treating the gender that predominantly experiences IBS, to treating patients with a characteristic that is always or almost always evaluated in establishing IBS, and to assessing symptoms for a duration of time that was common in diagnosing patients with IBS.”