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Lilly loses method patent after use was disclosed in earlier patent
Eli Lilly & Co. recently lost an appeal from a final judgment of the U.S. District Court for the Eastern District of Michigan, finding claims 2, 6, and 7 of U.S. Patent No. 5,464,826 invalid for obviousness-type double patenting over its earlier U.S. Patent No. 4,808,614. (See, Sun Pharmaceutical Industries v. Lilly, U.S. Court of Appeals for the Federal Circuit, 2010-1105).
Lilly markets Gemzar (gemcitabine) for the treatment of various forms of cancer. Both the '614 patent and the '826 patent cover gemcitabine and are so listed in the U.S. Food and Drug Administration's (FDA) Approved Drug Products with Therapeutic Equivalence Evaluations (the Orange Book) listing for Gemzar. The '614 patent claims gemcitabine, as well as a method of using gemcitabine for treating viral infections. The '826 patent, however, claims a method of using gemcitabine for treating cancer.
Specifically, the specification of the '614 patent states: "In addition to the antiviral utility of the present compounds, certain of the compounds of the present invention have also demonstrated excellent oncolytic activity in standard cancer screens. A particularly preferred compound with this utility is [gemcitabine]."
On Dec. 4, 1984, the same day that Lilly filed the continuation-in-part that resulted in the '614 patent, Lilly filed another patent application that ultimately issued as the '826 patent. The '614 patent does not claim a method of using any of the claimed nucleosides for treating cancer. Each claim of the '826 patent is directed to a method of treating cancer with an effective amount of a class of nucleosides, which includes gemcitabine.
Specifically, claim 1 of the '826 patent reads: "[a] method of treating susceptible neoplasms [i.e., cancer] in mammals comprising administering to a mammal in need of such treatment a therapeutically effective amount of the class of nucleosides."
Claim 2 of the '826 patent is specifically directed to a method of using gemcitabine.
After Sun Pharma filed an Abbreviated New Drug Application (ANDA) with the FDA for approval to market a generic version of Gemzar and certified that both the '614 patent and the '826 patent were invalid or not infringed, Sun filed suit against Lilly to try to get a court judgment affirming that the '826 patent is invalid and not infringed.
The district court sided with Sun that the claims of the '826 patent are invalid for obviousness-type double patenting over the earlier '614 patent after it concluded—in light of the '614 patent's disclosure of gemcitabine's anticancer use—that the claims are not patentably distinct.
The doctrine of double patenting is intended to prevent a patentee from obtaining an extension of a patent for the same invention or an obvious modification. The rule against double patenting takes two forms: statutory double patenting, which prohibits a later patent from covering the same invention, i.e., identical subject matter, as an earlier patent; and obviousness-type double patenting, which is a judicially created doctrine that prevents a later patent from covering a slight variation of an earlier patented invention.
Obviousness-type double patenting prohibits "claims in a later patent that are not patentably distinct from claims in a commonly owned earlier patent. An obviousness-type double patenting analysis consists of two steps. First, the court "construes the claim[s] in the earlier patent and the claim[s] in the later patent and determines the differences." Second, the court "determines whether those differences render the claims patentably distinct."
Lilly tried arguing that the double-patenting analysis did not apply because although the specification of the earlier '614 patent disclosed gemcitabine's use in treating both viral infections and cancer, the antiviral use provided the essential utility necessary to the patentability of the '614 patent's claim to gemcitabine. Lilly objected to what it said was the district court's extension of the obviousness-type double patenting analysis to any utility disclosed in the specification of an earlier patent.
The Federal Circuit summarily rejected Lilly's argument, saying that the analysis in earlier decisions show that obviousness-type double patenting encompasses any use for a compound that is disclosed in the specification of an earlier patent claiming the compound and is later claimed as a method of using that compound.
Thus, the rule that a "claim to a method of using a composition is not patentably distinct from an earlier claim to the identical composition in a patent disclosing the identical use," extends to any and all such uses disclosed in the specification of the earlier patent. In affirming the district court's decision that the patent was invalid, the court wrote that "[i]t would shock one's sense of justice if an inventor could receive a patent upon a composition of matter, setting out at length in the specification the useful purposes of such composition … and then prevent the public from making any beneficial use of such product by securing patents upon each of the uses to which it may be adapted."
The take-home message is that if you have uses for a compound that you intend to patent, you need to claim the uses on first disclosure.