The district court held that the claims of four of Cubist’s patents were invalid as being obvious and held that the claims of the fifth of Cubist’s patents were not invalid and were infringed.  The Federal Circuit affirmed.  On the claims that were not invalid and infringed, Hospira argued that the PTO had erred by issuing a certificate of correction changing one figure showing the structural diagram of the chemical structure of one of the formulas for the claimed drug.  The drawing was erroneous because, one of the components in the figure was the L-isomer, but was corrected to change that component to the D-isomer.  The Federal Circuit held that the PTO had not erred because the description of the formula in the patent specification was correct, even though the figure itself was not, and legal precedent holds that chemical structure is means of describing a compound; it is not the invention itself.  For the same reasons, the court held that the patentee had not violated the written description requirement with the erroneous figure.  Lastly, the court held that the patentees had not violated the recapture rule for reexamined patents.  Here, the amendments during the initial prosecution were to overcome an indefiniteness rejection, not to overcome prior art, and therefore recapture did not apply.

On the issue of obviousness on the four invalid patents, the held that the district court’s finding of obviousness was supported by the evidence and held that the secondary considerations of non-obviousness were insufficient to overcome the evidence of obviousness. 

Cubist Pharmaceuticals, Inc. v. Hospira, Inc., Case Nos. 2015-1197, -1204, -1259 (November 12, 2015); Opinion by: Bryson, joined by Wallach and Hughes; Appealed From: United States District Court for the District of Delaware, Sleet, J. Read the full opinion here.

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