Lilly loses method patent after use was disclosed in earlier patent

Eli Lilly & Co. recently lost an appeal from a finaljudgment 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 forobviousness-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 ofvarious forms of cancer. Both the '614 patent and the '826 patent cover gemcitabineand are so listed in the U.S. Food and Drug Administration's (FDA) ApprovedDrug Products with Therapeutic Equivalence Evaluations (the Orange Book)listing for Gemzar. The '614 patent claims gemcitabine, as well as a method ofusing 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 thecompounds of the present invention have also demonstrated excellent oncolyticactivity in standard cancer screens. A particularly preferred compound withthis utility is [gemcitabine]."

On Dec. 4, 1984, the same day that Lilly filed thecontinuation-in-part that resulted in the '614 patent, Lilly filed anotherpatent application that ultimately issued as the '826 patent. The '614 patentdoes not claim a method of using any of the claimed nucleosides for treatingcancer. Each claim of the '826 patent is directed to a method of treatingcancer with an effective amount of a class of nucleosides, which includesgemcitabine.

Specifically, claim 1 of the '826 patent reads: "[a] methodof treating susceptible neoplasms [i.e.,cancer] in mammals comprising administering to a mammal in need of suchtreatment a therapeutically effective amount of the class of nucleosides."

Claim 2 of the '826 patent is specifically directed to amethod 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 andcertified that both the '614 patent and the '826 patent were invalid or notinfringed, Sun filed suit against Lilly to try to get a court judgmentaffirming 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 ofgemcitabine's anticancer use—that the claims are not patentably distinct.

The doctrine of double patenting is intended to prevent apatentee from obtaining an extension of a patent for the same invention or anobvious modification. The rule against double patenting takes two forms:statutory double patenting, which prohibits a later patent from covering thesame invention, i.e., identical subjectmatter, as an earlier patent; and obviousness-type double patenting, which is ajudicially created doctrine that prevents a later patent from covering a slightvariation of an earlier patented invention.

Obviousness-type double patenting prohibits "claims in alater patent that are not patentably distinct from claims in a commonly ownedearlier patent. An obviousness-type double patenting analysis consists of twosteps. First, the court "construes the claim[s] in the earlier patent and theclaim[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 didnot apply because although the specification of the earlier '614 patentdisclosed gemcitabine's use in treating both viral infections and cancer, theantiviral use provided the essential utility necessary to the patentability ofthe '614 patent's claim to gemcitabine. Lilly objected to what it said was thedistrict court's extension of the obviousness-type double patenting analysis toany 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 doublepatenting encompasses any use for a compound that is disclosed in thespecification of an earlier patent claiming the compound and is later claimedas a method of using that compound.

Thus, the rule that a "claim to a method of using acomposition is not patentably distinct from an earlier claim to the identicalcomposition in a patent disclosing the identical use," extends to any and allsuch uses disclosed in the specification of the earlier patent. In affirmingthe 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 patentupon a composition of matter, setting out at length in the specification theuseful purposes of such composition … and then prevent the public from makingany beneficial use of such product by securing patents upon each of the uses towhich it may be adapted."

The take-home message is that if you have uses for acompound that you intend to patent, you need to claim the uses on firstdisclosure.

Stephen Albainy-Jenei is a patent attorney at Frost BrownTodd LLC, serving up chat at PatentBaristas.com. Write Albainy-Jenei withcomments or questions at Stephen@patentbaristas.com.