Lilly’s double patenting problems originated with the filing of application Serial No. 432,379 (the "379 application") in 1974. The ‘379 application contained claims for a class of compounds, therapeutic methods of using those compounds, and pharmaceutical compositions comprising those compounds. When the last patent stemming from the ‘379 patent issued in 1986, that application had spawned four divisional applications, three continuation applications, and six patents.
One of those divisional applications matured into United States Patent No. 4,018,895 (the "895 patent"). The first and only claim of the ‘895 patent covered the "administration of a pharmaceutical compound within a class of claimed compounds to treat depression in humans." The ‘895 patent expired in 1994.
The claim of the patent invalidated by the Federal Circuit in this case, Claim 7 of United States Patent No. 4,626,549 (the "549 patent"), matured from a continuation application. Claim 7 of the ‘549 patent related to "blocking the uptake of monoamine serotonin in an animal’s brain neurons through administration of the compound [fluoxetine hydrochloride]."
The judicially created doctrine of obviousness-type double patenting prohibits a patentee from "obtaining an extension of exclusive rights through claims in a later patent that are not patentably distinct from claims in an earlier patent." The Federal Circuit found that Claim 1 of the ‘895 patent covered the administration of fluoxetine hydrochloride for treating depression just like Claim 7 of the ‘549 patent. Accordingly, the court held Claim 7 of the ‘549 patent invalid for obviousness-type double patenting.
The Federal Circuit reached this result based on the difference between when a patentee claims a genus in an earlier patent and then claims a species in a later patent, and when the prior art discloses a genus and a later patent claims a species. Here, Lilly claimed a genus in the ‘895 patent and then claimed a species in the ‘549 patent. This double-patenting rendered the second Claim invalid.
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