In its brief, which asks the court to reverse the district court’s grant of summary judgment to Mayo on the grounds of section 101 invalidity, Novartis echoes many of the arguments made in the other briefs, i.e., that the district court erred in focusing its analysis on certain elements of the claim (in particular the "wherein clauses") while failing to consider the claim as a whole, that the claim as a whole satisfies the Bilski machine-transformation test, that the district court’s rationale, if taken to its logical extreme, would put claims to methods of treatment employing new drugs at risk, and that the decision threatens to stifle innovation in personalized medicine and health care in general.
Novartis also makes an argument that I don’t think appears in any of the other briefs that have been filed. In particular, Novartis argues that the district court’s claim construction is flawed because the court erroneously disregarded the claim’s preamble. In considering this argument, it is useful to look at the actual claim language.
Claim 1 of U.S. Patent No. 6,355,623 is representative:
A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising:
(a) administering a drug providing 6-thioguanine to a subject having said immune-mediated gastrointestinal disorder; and
(b) determining the level of 6-thioguanine in said subject having said immune-mediated gastrointestinal disorder,
wherein the level of 6-thioguanine less than about 230 pmol per 8 x 108 red blood cells indicates a need to increase the amount of said drug subsequently administered to said subject and
wherein the level of 6-thioguanine greater than about 400 pmol per 8 x 108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.
Patent claims can generally be broken down into three discrete elements – the preamble, transition and body. Most commonly, the transition is the word “comprising” (a word that has special significance in claim interpretation), the preamble is the language preceding the transition, and the body is the remainder of the claim. Thus, the preamble of Prometheus’ claim is “a method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder,” and the body of the claim is everything after “comprising.”
Significantly, the general rule is that the claim preamble is not taken into account when construing the scope of the claim. Rather, the function of the preamble normally is merely to identify what kind of invention is being claimed. It is the body of the claim which provides the claim limitations which define the claimed subject matter. However, as correctly noted by Novartis, the general rule against using the preamble in claim construction does not apply in certain circumstances, particularly when the preamble is “necessary to give life, meaning, and vitality” to the claim. Novartis argues, I think rather persuasively, that the claims at issue might warrant a consideration of the preamble in a manner that constrains the scope of the claims. I’m not sure if Prometheus ever made this argument; I don’t believe it appears in their appellant brief.
According to Novartis, consideration of the preamble and claim construction limits the claim to a “method of optimizing treatment whereby a dose administered to a patient is adjusted based on the determination of a level of drug metabolite.” If Novartis is correct, it could have some bearing on the patent eligibility of the claim. For example, in Bilski the Federal Circuit noted that the fundamental test for patent eligibility involves a determination of whether the claim “wholly preempts” a fundamental principle. In Prometheus, the alleged fundamental principle is the correlation between the level of drug breakdown products and optimal drug dosage. Alternatively, one might argue that the “wherein” clauses (which are really at the heart of the discovery upon which Prometheus' invention is based) constitute an attempt to patent a mental process, i.e., the recognition of a correlation. But when the claim is construed as limited to a method of optimizing treatment, it would appear that there are other substantial and useful non-infringing uses of the correlation, thus avoiding preemption of the principle.