No Need to Accentuate the Positive — Eliminate the Negative

In Inphi Corporation v, Netlist, Inc., [2015-1179] (November 13, 3015), the Federal Circuit affirmed the BPAI decision affirming the examiner’s final decision declining to reject claims amended during inter partes reexamination to add a negative limitation. At issue in this appeal is a negative claim limitation Netlist introduced by amendment, limiting the
claimed chip selects to exclude three particular types of signals (CAS, RAS, and bank-address signals):

wherein the system memory domain is compatible with a first number of chip selects, and the physical memory domain is compatible with a second number of chip selects equal to twice the first number of chip selects, wherein the plurality of memory devices comprises double-data rate (DDR) dynamic random-access memory (DRAM) devices and the chip selects of the first and second number of chip selects are DDR chip selects that are not CAS, RAS, or bank address signals.

The Federal Circuit said that “[n]egative claim limitations are adequately
supported when the specification describes a reason to exclude the relevant limitation.” Santarus, 694 F.3d at 1351.  The Federal Circuit characterized the issue as  whether the specification of the ’537 patent provides a “reason to exclude” CAS, RAS, or bank address signals that is sufficient to satisfy the written description requirement.  The Federal Circuit quoted from Santarus that:

Negative claim limitations are adequately supported when the specification describes a reason to exclude the relevant limitation. Such written description support need not rise to the level of disclaimer. In fact, it is possible for the patentee to support both the inclusion and exclusion of the same material.

The Federal Circuit said that the “reason” required by Santarus is provided, for instance,
by properly describing alternative features of the patented invention.

The parties agreed that the disclosure in the ’537 patent distinguishes among the relevant
signal types, but disagreed about whether that distinction creates a “reason to exclude” that satisfies the requirements of § 112, paragraph 1, and the Federal Circuit held that the disclosure as an alternative was a sufficient reason to exclude.

As long as the disclosure makes a distinction, you don’t have to accentuate the positive, or eliminate the negative, the disclosure will support a negative limitation.


Certificate of Correction to Correct Information Not Available When Patent Issued

Cubist Pharmaceuticals, Inc. v. Hospira, [2015-1197, 2015-1204, 2015-1259] (November 12, 2015), the Federal Circuit approved the use of a Certificate of Correction to correct information not available at the time the application was filed.

At the time the application 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 in the patent.  Years after the issuance of the patent researchers discovered that daptomycin actually contains the D-isomer of asparagine, not the L-isomer. Cubist sought to correct the error by requesting a certificate of correction from the Patent and Trademark Office (“PTO”) pursuant to 35 U.S.C. § 255, which was granted.

In subsequent infringement litigation with Cubist, Hospira argued that the PTO had erred by issuing the certificate of correction because the change in the structural diagram altered the substance of the claims, broadening their reach.  However, Cubist’s expert testified that the specification made it clear that the claims of the patent were directed to daptomycin, not to the variant containing the L-isomer of asparagine. Because it was plain that the claims were directed to daptomycin, it was appropriate for the PTO to correct the error in the structural diagram.

The Federal Circuit said that once the PTO has issued a certificate of correction, a
court may invalidate the certificate only upon a showing of clear and convincing evidence that it was improperly issued, which Hospira failed to do.  The Federal Circuit said that the problem with Hospira’s argument was that the district court did not view the change in the diagram as changing the scope of the claims at all. Instead, the district court regarded the change as simply conforming the structural diagram to the compound described in the specification and covered by the claims.