September 2012

A Claimed Intermediate Used in the Synthesis of a Compound Does Not Render a Later Claim Directed to the Compound Invalid for Obviousness-Type Double Patenting
Daniel A. Lev

In Eli Lilly & Co. v. Teva Parenteral Medicines, Inc., Nos. 11-1561, -1562 (Fed. Cir. Aug. 24, 2012), and Eli Lilly & Co. v. APP Pharmaceuticals, LLC, No. 12-1307 (Fed. Cir. Aug. 24, 2012), the Federal Circuit affirmed the district court’s finding that claims 1, 2, 3, and 7 of U.S. Patent No. 5,344,932 (“the ’932 patent”) are not invalid for obviousness-type double patenting.

The Trustees of Princeton University (“Princeton”) own the ’932 patent, which is exclusively licensed to Eli Lilly & Co. (“Lilly”).  Claims 1, 2, 3, and 7 of the ’932 patent are composition claims that specifically and generically cover pemetrexed, an anticancer drug marketed by Lilly under the brand name Alimta®.

Teva Parenteral Medicines, Inc., Barr Laboratories, Inc., and APP Pharmaceuticals, LLC (collectively “Teva”) filed ANDAs seeking approval to market generic versions of Alimta®.  Teva’s ANDAs included Paragraph IV certifications that the ’932 patent was invalid, unenforceable, or would not be infringed by the proposed generic formulations.  In response, Lilly and Princeton sued Teva for patent infringement.  Teva conceded infringement but argued that the asserted claims of the ’932 patent were invalid for obviousness-type double patenting over two prior patent claims:  (1) claim 3 of U.S. Patent No. 5,028,608 (“the ’608 patent”); and (2) claim 7 of U.S. Patent No. 5,248,775 (“the ’775 patent”).  Following a bench trial, the district court concluded that claims 1, 2, 3, and 7 of the ’932 patent were not invalid for obviousness-type double patenting, and enjoined approval of Teva’s proposed generic products until after expiration of Lilly’s exclusive rights.  Teva appealed.

On appeal, the Federal Circuit affirmed the district court’s decision, holding that the asserted claims of the ’932 patent are not invalid for obviousness-type double patenting over claim 3 of the ’608 patent or claim 7 of the ’775 patent.

Claim 3 of the ’608 patent recites an antifolate compound that is structurally related to pemetrexed, but was never advanced to clinical testing.  The only difference between the compound claimed in the ’608 patent and pemetrexed is that the latter has a phenyl group where the former has a thiophene group.  The ’608 patent issued more than three years before the ’932 patent.  The Federal Circuit framed the question as whether the asserted claims of the ’932 patent are patentably distinct from the compound claimed in the ’608 patent.

An obviousness-type double patenting analysis with respect to chemical claims “requires identifying some reason that would have led a chemist to modify the earlier compound to make the later compound with a reasonable expectation of success.”  Slip op. at 15 (quoting Otsuka Pharm. Co. v. Sandoz, Inc., 678 F.3d 1280, 1297 (Fed. Cir. 2012)).  In affirming the district court’s decision, the Federal Circuit found that the district court had considered the parties’ arguments and evidence, including their conflicting expert testimony, when it credited Lilly’s evidence of nonobviousness, a finding which the Federal Circuit accorded considerable deference.  In particular, the district court had not found that substituting a phenyl group for the thiophene group of the compound claimed in the ’608 patent was the one possibility, among many possible modifications, that would have been successful if pursued.  Therefore, the Federal Circuit held that the district court correctly concluded that the asserted claims of the ’932 patent were not invalid for obviousness-type double patenting over the ’608 patent, because there was no motivation to derive pemetrexed from the compound claimed in the ’608 patent or any expectation of success in doing so.

Claim 7 of the ’775 patent is directed to an intermediate in the synthesis of pemetrexed, and was issued before the ’932 patent.  Teva argued that the ’775 patent discloses the use of the claimed intermediate in the synthesis of pemetrexed and that this disclosure renders the later “composition of matter” claims invalid for obviousness-type double patenting.  In support of this argument, Teva relied on a line of cases that held a later “method of use” claim invalid for obviousness-type double patenting over an earlier patent claiming a compound and disclosing the later-claimed use as part of the compound’s utility.

The Federal Circuit rejected Teva’s argument.  First, the Court noted that the obviousness-type double patenting inquiry generally turns on a comparison between a patentee’s earlier and later claims, with the earlier patent’s disclosure considered only as necessary to construe its claims.  The Court held that the cases Teva relied on were not applicable to the present facts.  The claims-at-issue recite two separate compounds, not a composition and its previously disclosed use, which negates Teva’s argument by itself.  Additionally, pemetrexed and the intermediate claimed in the ’775 patent exhibit significant structural differences, and pemetrexed can be synthesized by several routes that do not involve the claimed intermediate.  Therefore, the Federal Circuit affirmed the district court’s holding that the asserted claims of the ’932 patent are not invalid for obviousness-type double patenting over the ’775 patent.

Finally, the Federal Circuit considered whether objective indicia of nonobviousness are relevant to an obviousness-type double patenting analysis and held erroneous the district court’s repudiation of Lilly’s evidence of objective indicia of nonobviousness.  The Court noted that such evidence should be considered in the obviousness-type double patenting context.  However, because the district court sided with Lilly and upheld the validity of the asserted claims of the ’932 patent, the Court found the district court’s error to be harmless.