Addressing whether a negative claim limitation failed to meet the written description requirement, the U.S. Court of Appeals for the Federal Circuit affirmed a decision from the U.S. Patent and Trademark Office Patent Trial and Appeal Board (Board), finding that a description in a specification to exclude a genus in general is insufficient to support a negative claim limitation that excludes a specific species.  In re Bimeda Research & Development Ltd., Case No. 12-1420 (Fed. Cir., July 25, 2013) (Clevenger, J.) (Rader, C.J., concurring).

At issue in this case was Bimeda’s ’400 patent, directed to methods of preventing the onset of bovine mastitis by employing a physical barrier within the teat canal to block mastitis-causing organisms.  According to the patent, the physical barrier provided a “non-antibiotic approach” to prevent infections.

After the patent was issued, the USPTO ordered ex parte reexamination in view of prior art that taught the use of a physical barrier in conjunction with certain anti-infective agents, such as antibiotics and acriflavine (which is an antiseptic agent).  Bimeda amended the claim to recite the use of “an acriflavine-free” seal formulation to form a physical barrier.  The amended claim was rejected by the examiner for lacking written description, because the term “acriflavine” was not mentioned anywhere in the specification.  The Board affirmed the examiner’s rejection, holding that the specification only disclosed the exclusion of a broad genus (anti-infectives), but failed to demonstrate “possession” of a formulation that excluded a particular species (acriflavine).  There was no guidance (or “blaze marks”) in the specification to guide a skilled artisan towards excluding that particular species.  Accordingly, the Board held that the disclosure of the patent failed to convey the full scope of what was affirmatively claimed—a formulation that excluded acriflavine but could include other anti-infective agents.  Bimeda appealed. 

Bimeda argued to the Federal Circuit that the patent disclosure evidenced “a tacit indifference to the presence or absence of specific anti-infectives,” and contended that the disclosure therefore supported a claim that excluded one particular anti-infective (but permitted the use of others, such as antibiotics).  The Federal Circuit rejected the argument, noting that the “summary of the invention” of the patent described the invention’s “non-antibiotic approach” for preventing mastitis and explained how this approach achieved the benefit of “meeting consumer preferences for reducing the levels of antibiotics used in food production.”  The remainder of the patent similarly distinguished the invention due to its ability to prevent mastitis without using antibiotics.  Accordingly, the Court explained that the disclosure was inconsistent with a claim that excluded acriflavine, but could include antibiotics and thus failed to convey “possession” of the full scope of the claim.

In his concurrence, Chief Judge Rader agreed that the specification did not sufficiently disclose a formulation which excluded a specific species of the anti-infective genus, but permitted the presence of other species.  However, Rader noted the dilemma of meeting the written description requirement under on the traditional “possession” analysis, because the “possession” requirement placed the patentee in a Catch-22:  To satisfy the written description, “the patentee must show possession of something it specifically claims it does not possess.”

Practice Note: 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.  See, e.g., Santarus and the University of Missouri v. Par Pharma.  (“The claim limitation that the Phillips formulations contain no sucralfate is adequately supported by statements in the specification expressly listing the disadvantages of using sucralfate.”)  The Federal Circuit in this case found that the main problem of Bimeda’s patent is that a formulation that includes antibiotics but excludes acriflavine is contrary to the “non-antibiotic approach” disclosed in the patent.