By Kevin E. Noonan —
An astute reader has asked, regarding our post concerning EXACT Sciences' announcement of the issuance of U.S. Patent No. 7,485,420, whether the claims of the '420 patent would be invalid under the Federal Circuit's In re Bilski standard for patentable subject matter. The independent claims of the '420 patent are:
a) obtaining a sample from a human patient; and
b) assaying said sample for the presence or absence of methylation within a nucleotide sequence selected from the group consisting of SEQ ID NOs: 40-45,
wherein the presence of methylation within any one of said nucleotide sequence is indicative of the likelihood that the human patient has colon neoplasia.
13. A method for detecting the likelihood that a human subject has colon neoplasia, comprising detecting vimentin protein or nucleic acid expression level in a sample from the human subject, wherein reduced expression level of vimentin protein or nucleic acid relative to a control sample from a healthy subject is indicative of the likelihood that the human subject has colon neoplasia.
17. A method for monitoring over time colon neoplasia in a human subject, comprising:
a) detecting the methylation status of a vimentin nucleotide sequence selected from the group consisting of SEQ ID NOs: 40-45 in a sample from the human subject for a first time; and
b) detecting the methylation status of any one of said vimentin nucleotide sequence of step (a) in a sample from the same human subject at a later time;
wherein absence of methylation in the vimentin nucleotide sequence taken at a later time and presence of methylation in the vimentin nucleotide sequence taken at the first time is indicative of regression of colon neoplasia; wherein presence of methylation in the vimentin nucleotide sequence taken at a later time and absence of methylation in the vimentin nucleotide sequence taken at the first time is indicative of progression of colon neoplasia.
Since the Supreme Court has not yet spoken on the issue, the standard for patentability of process (method) claims is the one announced by the en banc Federal Circuit in Bilski: for a process to be eligible for patenting (i.e., to be deemed patentable subject matter under 35 U.S.C. § 101), it must be claimed to include one or the other of these elements: (1) it is tied to a particular machine or apparatus, or (2) it transforms a particular article into a different state or thing.
The invention in Bilski was a method for hedging risk in commodities trading, subject matter seemingly far-removed from diagnostic claims such as EXACT's colorectal cancer detection method.
However, the Federal Circuit has had the occasion, since its Bilski decision, to consider the patentability of claims more similar to EXACT's claims than those invalidated in Bilski. In Classen Immunotherapeutics, Inc. v. Biogen Idec, the CAFC affirmed a district court decision invalidating the claims in Classen's U.S. Patent No. 5,723,283:
The Federal Circuit in Classen made short work of any analysis of how Bilski's patentability rubrics apply to Classen's claims: the Court's decision read in its entirety:
There are distinctions that can be drawn, of course, between Classen's claims and EXACT's claims, one of which is that the Classen claims are directed to an immunization schedule, and expressly recite that the results of the immunization procedure be "compared" between an experimental and a control group. This "comparing" step implicates the deficiency found by three Supreme Court justices (Breyer, Souter, and Stevens) in their dissent from dismissal of the appeal in the Laboratory Corp. v. Metabolite Labs., Inc. (LabCorp) case. There, the claim at issue read as follows:
In their dissent, the Justices opined:
* * *
Even were I to assume (purely for argument's sake) that claim 13 meets certain general definitions of process patentability, however, it still fails the one at issue here: the requirement that it not amount to a simple natural correlation, i.e., a "natural phenomenon." See Flook, supra, at 588, n. 9 (even assuming patent for improved catalytic converter system meets broad statutory definition of patentable "process," it is invalid under natural phenomenon doctrine); Diehr, 450 U. S., at 184–185 (explaining that, even if patent meets all other requirements, it must meet the natural phenomena requirement as well).
At most, respondents have simply described the natural law at issue in the abstract patent language of a "process." But they cannot avoid the fact that the process is no more than an instruction to read some numbers in light of medical knowledge. Cf. id., at 192 (warning against "allow[ing] a competent draftsman to evade the recognized limitations on the type of subject matter eligible for patent protection"). One might, of course, reduce the "process" to a series of steps, e.g., Step 1: gather data; Step 2: read a number; Step 3: compare the number with the norm; Step 4: act accordingly. But one can reduce any process to a series of steps. The question is what those steps embody. And here, aside from the unpatented test, they embody only the correlation between homocysteine and vitamin deficiency that the researchers uncovered. In my view, that correlation is an unpatentable "natural phenomenon," and I can find nothing in claim 13 that adds anything more of significance.
The Supreme Court remanded the LabCorp case without reaching a decision, and Chief Justice Roberts took no role in the decision to remand on the grounds that certiorari had been improvidently granted, so there is no way to know whether Justice Breyer's opinion in dissent is truly limited to the Justices who joined him in dissent. Bilski has petitioned for certiorari, so the Court may address the propriety of the Federal Circuit's application of the Bilski formula to the Classen claims.
EXACT's claims avoid a direct recitation of the "buzzwords" like "compared" and "correlated," but that may not be enough: after all, saying that the level of methylation in vimentin gene sequences is "reduced" poses the question "compared to what?" and therein may be the problem. Of course, "comparison" is required in many claims that, prior to Bilski, would have been thought to be unambiguously patentable, for example, claim 1 of U.S. Patent No. 7,464,002:
The trivial answer is that this claim is directed at "diagnosing" a machine, and so fall under the "machine" prong of the test. But a better reading of Bilski is that the method must be performed by a machine, not on a machine, and so that line of reasoning does not appear to be a valid distinction. The level of uncertainty produced by the Federal Circuit in Bilski, encouraged or at least catalyzed by Justice Breyer's dissent in LabCorp, is the polar opposite to the avowed purpose of Congress in establishing this specialized appellate court, i.e., to bring greater certainty to patent law than had been achieved by the several regional circuit Courts of Appeal. It is up to the Supreme Court (if it deigns to) to decide whether to overturn the Federal Circuit's mechanical, bright-line test for patentability in Bilski (which is frankly in direct conflict with the Supreme Court's own view of what is patentable enunciated in Diamond v. Chakrabarty), and thus to follow its decade-long pattern of imposing on the Federal Circuit its conception of the metes and bounds of U.S. Patent Law.
For information regarding this or other related topics, please see:
• "Patent Profile: EXACT Sciences Announces Issuance of Colorectal Cancer Screening Patent," February 4, 2009
• "Classen Immunotherapies, Inc. v. Biogen Idec (Fed. Cir. 2008)," December 22, 2008
• "Personalized medicine: A Patent Office Perspective," December 11, 2008
• "The Relevance of In re Bilski to the Patentability of the Metabolite Claim," November 17, 2008
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