Although “[i]t is well-settled that a narrow species can be non-obvious and patent eligible despite a patent on its genus,” species are unpatentable when the prior art disclosures “describe the genus containing those species such that a person of ordinary skill in the art would be able to envision every member of the class.” For example, a patent that claims to treat a subset of patients with more severe symptoms is an obvious variant of a patent that claims treatment of patients generally.

Background / Facts: The patent being asserted here is directed to treating rheumatoid arthritis by co-administering two drugs, and is derived from a continuation of another patent of which the accused infringer is a licensee. The second patent is nearly identical to the first but claims treatment of a more specific patient group: individuals with “active disease.”

Issue(s): Whether a patent that claims to treat a subset of patients with more severe rheumatoid arthritis is an obvious (double-patenting) variant of a patent that claims treatment of rheumatoid arthritis patients generally.

Holding(s): Yes. “To be sure, obviousness is not demonstrated merely by showing that an earlier expiring patent dominates a later expiring patent. … It is well-settled that a narrow species can be non-obvious and patent eligible despite a patent on its genus. … But not every species of a patented genus is separately patentable.” In particular, when a “genus is so limited that a person of ordinary skill in the art can ‘at once envisage each member of this limited class,’ … a reference describing the genus anticipates every species within the genus. … Here, we think it is clear that a reader of the [first] patent could have easily envisioned a species limited to sicker patients. The district court was correct in concluding that the species of the [later] patent was not patentably distinct from the genus of the [earlier] patent,” and therefore invalid for double patenting.

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