IP Law Daily Asserted claims of patent relating to Merck’s Invanz antibiotic were obvious, despite commercial success
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Thursday, October 26, 2017

Asserted claims of patent relating to Merck’s Invanz antibiotic were obvious, despite commercial success

By Cheryl Beise, J.D.

The federal district court in Wilmington, Delaware, did not err in finding that several claims of a patent for preparing a stable formulation of the antibiotic compound ertapenem owned by Merck Sharp & Dohme were invalid as obvious, the U.S. Court of Appeals for the Federal Circuit has held. Substantial record evidence supported the district court’s conclusion that the claimed process would have been obvious at the time the invention was made. Merck’s objective evidence of obviousness—commercial success and copying by others—was insufficient to overcome the "strong prima facie case of obviousness." Circuit Judge Pauline Newman filed a dissenting opinion (Merck Sharp & Dohme Corp. v. Hospira, Inc., October 26, 2017, Lourie, A.).

Merck Sharp & Dohme Corp. ("Merck") owns U.S. Patent Nos. 6,486,150 ("the ’150 patent") and 5,952,323 ("the ’323 patent"), relating to formulas and methods of stabilizing ertapenem, an injectable antibiotic and a member of a class of antibiotics called carbapenems. The patents were commercialized in connection with Merck’s injectable antibiotic product Invanz. When Hospira, Inc., notified Merck that it had filed an abbreviated new drug application ("ANDA") to produce generic versions of Invanz, Merck sued for infringement of both patents.

Following a bench trial, the district court concluded that the asserted claims (2 and 4-6) of the ’323 patent were valid and infringed and the asserted claims (21-34) of the ’150 patent were infringed, but were invalid as obvious over the ’323 patent and an international patent application filed by Merck’s employee, Om Almarsson, PCT publication WO 98/18800 ("Almarsson").

Merck appealed, challenging the district court’s finding that independent claim 21 (and the narrower dependent claims 22-34) of the ’150 patent were obvious. Merck argued that the district court erred in finding that the claims would have been obvious over either reference because (1) none of the claimed steps was disclosed in the prior art, (2) the prior art taught away from the claimed invention because the prior art focused solely on degradation by dimerization, not hydrolysis, and (3) the "knowledge, creativity, and common sense" of a skilled artisan cannot supply a missing claim limitation.

The Federal Circuit disagreed with Merck, finding that substantial record evidence supported the district court’s conclusion that the claimed process would have been obvious at the time the invention was made. Merck did not dispute that the ’323 patent and Almarsson taught exposing ertapenem to a carbon dioxide solution, while maintaining a pH range of 6.0–9.0, followed by lyophilization. Merck also did not dispute that hydrolysis was a known degradation pathway that one of ordinary skill would have sought to minimize. While none of the three steps of claim 21 was individually taught by the prior art, the district court determined that the "recipe" for the final formula-ion was disclosed and the three steps leading to that formulation were nothing more than conventional manufacturing steps. According to the Federal Circuit, it was reasonable for the district court to deduce from the evidence that the order and detail of the steps disclosed by claim 21 for minimizing both hydrolysis and dimerization, if not already known, would have been discovered by routine experimentation while implementing known principles.

Regarding Merck’s objective evidence of obviousness, the district found that commercial success and copying by others (Hospira) were shown, but that the objective evidence could not overcome the "strong prima facie case of obviousness" established by Hospira. Merck argued that the court improperly discounted Merck’s objective evidence. The Federal Circuit, however, discerned no clear error in the district court’s conclusion that Merck’s evidence of commercial success could not overcome the weight of the evidence that the claimed process was substantially described in the prior art and required only improvement by the use of established variations.

Considering all the evidence, the Federal Circuit held that the district court did not err in finding the invention to have been obvious at the time the invention was made.

Dissenting opinion. Circuit Judge Pauline Newman wrote in dissent to express her opinion that the Federal Circuit in this and several other cases has strayed from the proper analytical standard when evaluating obviousness. In Judge Newman’s view, the court’s inconsistent treatment of the procedures and burdens relating to evidentiary factors of obviousness has caused district court to err.

Judge Newman recommends a consistent return to the four-factor test the Supreme Court established in Graham v. John Deere Co., 383 U.S. 1 (1966). The four Graham factors are: (1) the scope and content of the prior art; (2) the differences between the claimed invention and the prior art; (3) the level of ordinary skill in the field of the invention; and (4) objective ("secondary") considerations such as commercial success, failure of others, and long-felt need. While some Federal Circuit decisions properly apply the Graham factors, others "appear to have sought a shortcut, and converted three of the four Graham factors into a self-standing ‘prima facie’ case, whereby the objective considerations must achieve rebuttal weight," Judge Newman said.

The present case fell into the latter category. The district court found that Hospira "made a prima facie showing" based solely on the prior art. Thus, the district court weighed that evidence against the conclusion that the order and detail of the steps would have been discovered by routine experimentation, and placed the obligation of achieving rebuttal weight on the fourth Graham factor. However, as the Supreme Court established, it is incorrect to consign the objective evidence to rebuttal against the other three Graham factors.

Judge Newman agreed with Merck that the question is not whether the evidence of copying and commercial success "could not overcome the weight of the competing evidence of obviousness of the claimed process" but rather whether the entirety of the evidence relating to the Merck process, including the evidence of copying and commercial success, establish obviousness. Shifting one of the four Graham factors to rebuttal distorts the placement and the burden of proof, according to Judge Newman.

"It is time to restore conformity to precedent, in the interest of stability of practice and procedure, and predictability and fairness of result," Judge Newman said, adding that she would "reestablish the proper analytic criteria under the four Graham factors," and remand the case to the district court "to apply the correct law."

The case is No. 2017-1115.

Attorneys: Jessica Lynn Ellsworth (Hogan Lovells US LLP) for Merck Sharp & Dohme Corp. Thomas J. Meloro (Willkie Farr & Gallagher LLP) for Hospira, Inc.

Companies: Merck Sharp & Dohme Corp.; Hospira, Inc.

MainStory: TopStory Patent FedCirNews

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