Cubist Pharmaceuticals, Inc. v. Hospira, Inc.


Docket Nos. 2015-1197, 2015-1204, 2015-1259

WALLACH, BRYSON, HUGHES
November 12, 2015

Brief Summary: DC conclusion that the certificate of correction was properly issued affirmed (“simply correcting an error in the diagram of Formula 3 without changing the scope of the patent”). DC conclusions that four later-filed Cubist patents encompassing dosing regimens and higher purity daptomcyin are invalid for anticipation or obviousness affirmed.

Summary: Cubist appealed DC finding that four patents encompassing the antibiotic daptomycin were invalid for anticipation or obviousness. Hospira appealed DC finding that a certificate of correction for Cubist’s RE39,071 (issued from Eli Lilly’s US 5,912,226) was not improperly granted. The opinion first addressed the certificate of correction, which was issued to “correct” the chemical structure encompassing daptomycin, changing L-Asp to D-Asp. The opinion explained that “[a]t the time the application for the ‘226 patent was filed, and until well after that patent was issued, it was universally believed that the asparagine amino acid in daptomycin was the L-isomer of asparagine, as set forth in the structural diagram” of the claim. This was until “[y]ears after the issuance of the ‘226 patent and after the reissue application for the ‘071 patent was filed”, when “Lilly researchers discovered that daptomycin actually contains the D-isomer”. Hospira’s expert testified that the L-isomer is “an entirely different compound” but “admitted..that he had not considered the specification of the ‘071 patent in reaching his determination”. Cubist’s expert testified that the ‘071 specification “made it clear that the claims of the ‘071 patent were directed to daptomycin, not to the variant containing the L-isomer”. The DC characterized the correction “as simply correcting an error in the diagram of Formula 3 without changing the scope of the patent” and “agreed with Cubist that the specification made clear that the patent claimed the daptomycin compound all along; the pre-correction version merely misidentified the stereoisomer” (“the specification as a whole ‘confirms that the Formula 3 compound identified in the claims is truly D-asparagine daptomycin, the by-product of the fermentation process’ described in the specification.”) It concluded “Hospira had not satisfied its burden to show that the certificate of correction was invalid” (a “heavy burden” requiring clear and convincing evidence). On appeal, Hospira argued the correction “was not a change of ‘minor character,’ as provided for in section 255” (Superior Fireplace, FC 2001). The FC panel explained that “[t]he problem with Hospira’s argument is that the district court did not view the change in the diagram as changing the scope of the claims at all” but “simply conform[ed] the structural diagram of Formula 3 to the compound described in the specification and covered by the claims” Further, the FC panel explained, “the original structure diagram in the ‘071 patent did not establish that the patent was directed to a compound other than daptomycin” (Regents of Univ. N.M., FC 2003 (a chemical structure is “simply a means of describing a compound; it is not the invention itself”)) Contrasting this case to Bayer (FC 2013) in which Bayer did not seek to change the description of a dioxygenase as a monooxygenase (which was known before the patent issued) and the court found it should not be interpreted as written, the FC explained that here “the applicants sought…to correct the structural diagram, which was based on a previous misunderstanding of the chemical structure of the claimed compound.” Hospira also argued that if the correction was valid, the claims should fail the written description requirement, but the FC panel agreed with the DC that “one skilled in the art would have understood that the inventors possessed and were working with the naturally occurring fermentation product, i.e., the daptomycin molecule containing D-asparagine…It was enough that the specification disclosed relevant identifying characteristics that distinguished daptomycin from other compounds and thus showed that the inventors had possession of daptomycin, even though they may not have had an accurate picture of the entire chemical structure…In this case, the applicants claimed only what they had produced-the daptomycin molecule-which they had identified in several ways” (Invitrogen, FC 2005, contrasting In re Wallach, FC 2004 (possession of the protein and partial amino acid sequence did not entitle applicants to claimed DNA molecules)). Hospira’s recapture argument was also rejected as the claim at issue had only been rejected for indefiniteness and not cancelled “to avoid prior art” (even though it was argued by the applicants to be nonobvious). The DC found claims of the ‘967 (dosing to minimize skeletal muscle toxicity) and ‘689 (48 hour dosing) patent claims anticipated (inherently disclosed) or obvious “in view of the known properties of daptomycin” and similar antibiotics, and the FC affirmed these conclusions (and was not convinced by Cubist’s evidence of secondary considerations (e.g., success not attributable to the dosage and interval protocols of the claims)). A second pair of patents, the “purity patents” (e.g., “essentially free of each of 14 identified impurities”, “less than 0.5% of each impurity”), was also held invalid for anticipation or obviousness in view of an earlier Lilly ‘843 patent and other references disclosing methods for purifying daptomycin. The FC panel agreed with the DC’s obviousness conclusions, and was not convinced by Cubist’s secondary consideration arguments.

This entry was posted in Certificate of Correction, Obviousness, Written description. Bookmark the permalink.

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