Yesterday, a divided panel of the Federal Circuit affirmed the district court’s narrow claim construction based on the applicant’s prosecution history disclaimer in Biogen IDEC v. GlaxoSmithKline.
Biogen obtained a patent that covered a method for treating patients with Chronic Lymphocytic Leukemia (CLL) by administering a therapeutically effective amount of anti-CD20 antibody. Anti-CD20 antibodies are antigen proteins that are capable of being used in cancer treatment. At issue in the case was the meaning of the term “anti-CD20 antibody.”
During prosecution of the patent, the examiner rejected the claims for lack of enablement. The claims were not enabled under the broadest reasonable interpretation standard used by the PTO for “any and all anti-CD20 antibodies, no matter the specificity or affinity for the specific epitope on the circulating tumor cells.” The examiner acknowledged that the specification did enable certain antibodies, such as RITUXAN® (rituximab), but was silent as to necessary specificity and affinity for other anti-CD20 antibodies.
The applicant responded that those of skill in the art would know that
even though antibodies directed to the same antigen might have different affinities and functional characteristics, one of skill in the art could readily identify an antibody that binds to CD20 with similar affinity and specificity as does RITUXAN® using techniques that are well known in the art. . . . With that knowledge in hand, the skilled artisan could readily produce anti-CD20 antibodies using similar techniques, and screen such antibodies for those having an affinity and functional activity similar to RITUXAN®.
The examiner then withdrew the enablement rejection and the claims were allowed.
GSK developed an anti-CD20 antibody with distinctly different characteristics from RITUXAN®. Biogen sued GSK for infringement.
The district court construed the term “anti-CD20 antibody” to mean “rituximab and antibodies that bind to the same epitope of the CD20 antigen with similar affinity and specificity as rituximab.” This construction was based on Biogen’s disclaimer during prosecution of the patent to overcome the examiner’s enablement rejection. Biogen stipulated that, under this construction, GSK did not infringe the claims of the patent.
On appeal, Biogen argued for the ordinary and customary meaning of the anti-CD20 antibody claim term. The court acknowledged that to overcome this heavy presumption of the ordinary meaning, a “clear and unmistakable disavowal” by the applicant during prosecution is required. The majority ruled that the applicant did make such a disavowal in this case.
According to the court, rather than challenging the examiner’s understanding of the “anti-CD20 antibody” claim term, the applicant merely argued that the claims were enabled for anti-CD20 antibodies that are similar to RITUXAN®. The applicant seemed to acquiesce to the examiner’s assertion that the claims were not enabled for other types of anti-CD20 antibodies.
Although Biogen argued that the applicant was discussing functional and affinity characteristics of anti-CD20 antibodies generally, and suggested that those skilled in the art would apply their understanding of the selection of such antibodies similar to the selection of RITUXAN®, the court instead held that the statement demonstrated a disavowal of claim scope of reasonable clarity and deliberateness.
This case is highly unusual in that prosecution history disclaimers are usually a result of the applicant’s statements during prosecution, not the examiner’s. The court, however, was unconvinced.
This case deals not only with applicants letting stand an examiner’s narrow characterization of a claim term, but also their adoption of that characterization to overcome the examiner’s enablement rejection.
Judge Plager dissented from the majority opinion. He argued that the give-and-take with the examiner is part of a negotiation with the applicant. Such negotiation often results in ambiguous statements as in this case. These less-than-clear statements should not be used against the applicant as they do not enhance the prosecution history’s notice function to the public. Such is the case here. Judge Plager would reverse and use the ordinary meaning of the term.
It seems fairly clear that in this case Judge Plager is correct. The record seems less than clear as to why the examiner withdrew the enablement rejection. Was it because the applicant disclaimed certain claim scope that was considered non-enabled? Was it because the examiner was convinced by the applicant’s argument that by demonstrating enablement for certain anti-CD20 antibodies that it was enabled for others as well? This is definitely not a clear and unmistakable disavowal of claim scope.
The lesson, however, is that applicants should rebut all of the examiner’s statements in office actions with which he does not agree. In this case, the applicant may believe that he did just that. He presented an argument that overcame the examiner’s rejection. This is a really tough opinion on this issue.
Earlier in my career, I worked with an attorney in the past who taught me to use language such as the following.
To avoid any unintended consequences to the contrary, the undersigned respectfully does not accept or acquiesce in any statement, argument, or description in the Office Action except as expressly stated herein.
While this language generally seems to be overkill, and seems to be merely boilerplate, it would (hopefully) avoid a situation such as in this case.