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Federal Circuit Affirms Invalidity of Lilly's Gemzar Patent for Obviousness-Type Double Patenting

By Aaron Barkoff

Sun Pharm. Indus. v. Eli Lilly & Co., No. 2010-1105 (Fed. Cir. 2010)

The principle behind the doctrine of double patenting is simple:  a person may not obtain two patents on the same invention.  The doctrine "is intended to prevent a patentee from obtaining a timewise extension of [a] patent for the same invention or an obvious modification thereof."

The two patents at issue in this case are U.S. Patent No. 4,808,614 and 5,464,826.  Both are listed in the Orange Book with respect to Lilly's drug Gemzar (gemcitabine), a nucleoside analog used for the treatment of cancer.  The '614 patent claims gemcitabine, as well as a method of using gemcitabine for treating viral infections.  The '826 patent claims a method of using gemcitabine for treating cancer.  The '614 patent issued on February 28, 1989 and expired on May 15, 2010 (Lilly chose the '614 patent for a patent term extension under 35 USC 156), while the '614 patent issued on November 7, 1995 and will expire on November 7, 2012 -- two-and-a-half years after the expiration of the '614 patent.

In August 2009, the U.S. District Court for the Eastern District of Michigan granted Sun's motion for partial summary judgment that the asserted claims of the later-expiring '826 patent are invalid for obviousness-type double patenting over the earlier-expiring '614 patent.  The court found that given the '614 patent's disclosure of gemcitabine's anticancer use, claim 12 of the earlier '614 patent, which claims gemcitabine, and claims 2, 6 and 7 of the later '826 patent, which claim a method of using gemcitabine for cancer treatment, are not patentably distinct.

In an opinion released earlier today, the Federal Circuit affirmed the district court's decision of invalidity, and in doing so affirmed its prior holding of Pfizer v. Teva (Fed. Cir. 2008) and Geneva v. GlaxoSmithKline (Fed. Cir. 2003):  "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."  The Federal Circuit stated, "In both cases, we found claims of a later patent invalid for obviousness-type double patenting where an earlier patent claimed a compound, disclosing its utility in the specification, and the later patent claimed a method of using the compound for a use described in the specification of the earlier patent."

According to the Federal Circuit opinion, Lilly attempted to distinguish Pfizer and Geneva by contending "that in both cases, the specification of the earlier patent disclosed a single use for the claimed compound, which was an essential part of the patented invention and thus necessary to patentability."  By contrast, here, "the specification of the earlier '614 patent disclosed gemcitabine's use in treating both viral infections and cancer, [but] the antiviral use provided the essential utility necessary to the patentability of the '614 patent's claim to gemcitabine."  In other words, because the antiviral use was the key use in the earlier patent, the cancer use claimed in the later patent should be upheld.

The Federal Circuit, however, disagreed with Lilly's characterization of Pfizer, stating that in that case, "the earlier patent's specification unambiguously disclosed more than one utility for the claimed compound."  In addition, the court explained that Lilly's proposed "single, essential utility test" would be "unworkable," because "where an earlier patent specification describes multiple uses for a compound, a court would be unable to identify the one use that was 'essential' or 'necessary' to patentability."  According to the court, Lilly's counsel conceded this point at oral argument.

In a press release today, Lilly's general counsel stated that Lilly "strongly disagrees" with the Federal Circuit's ruling and "will consider all possible legal options," including a petition for rehearing.

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Full post as published by Orange Book Blog: At the Intersection of Patent Law and FDA Law on July 29, 2010 (boomark / email).