'Bilski' Does Not Change 'Prometheus' Ruling; Diagnostic Tests Again Held Patent Eligible

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In a case on remand from the U.S. Supreme Court, the U.S. Court of Appeals for the Federal Circuit again held Dec. 17 that claimed methods for calibrating the proper dosage of a drug for treating autoimmune diseases are patentable subject matter under Section 101 of the Patent Act (Prometheus Laboratories Inc. v. Mayo Collaborative Services, Fed. Cir., No. 2008-1403, 12/17/10).

The Federal Circuit panel had previously found the medical diagnosis method claims patent eligible under its In re Bilski machine-or-transformation test (78 PTCJ 635, 9/25/09). The Supreme Court indicated in Bilski v. Kappos that passing the test does not necessarily mean that a claim is not directed to an unpatentable abstract idea. The high court vacated the Prometheuspanel's decision and remanded the case accordingly.

A reconstituted Federal Circuit panel in the instant case again used the machine-or-transformation test as “an investigative tool,” as the high court had allowed, and held that the claims asserted passed the transformation prong of the test.

The court did not end its analysis there, though, as it further concluded that the asserted claims did not preempt all uses of the correlations between the results of the diagnostic tests and the toxicity and efficacy of the drug dosage; that the testing steps are not mere data gathering; and that a final “warning” step requiring no physical action by a physician did not negate patent eligibility.

Patent for Measurement of Metabolite Levels.

Prometheus Laboratories Inc. is the exclusive licensee of two patents (6,355,623 and 6,680,302) which involve measuring the level of certain metabolites in the blood of patients taking thiopurine drugs, including the anti-Crohn's disease drug azathioprine (AZA), for treatment of either gastrointestinal or non-gastrointestinal autoimmune diseases.

The patented test is claimed as methods providing a means to measure the level of two metabolites: 6-thioguinine (6-TG) and 6-methylmercaptopurine (6-MMP), whereby metabolite levels greater than certain threshold levels of either one provide a “warning” of toxicity or inefficacy and indicate to the treating physician that an adjustment in drug dosage may be required. The claims at issue do not include a step for further action by the physician.

Prometheus brought a patent infringement suit against Mayo Collaborative Services, alleging that Mayo's tests measuring the same metabolites infringe the patents.

Judge John A. Houston of the U.S. District Court for the Southern District of California found the patents invalid for lack of statutory subject matter under 35 U.S.C. §101. Prometheus Laboratories Inc. v. Mayo Collaborative Services, No. 04cv1200 JAH (RBB), 86 USPQ2d 1705 (S.D. Cal. Mar. 28, 2008) (75 PTCJ 642, 4/18/08).

He agreed with Mayo that because the steps of the claims “embody only the correlations themselves,” the claims recite a natural phenomenon and are excluded from patentability.

Federal Circuit Overturns Lower Court.

On appeal, Prometheus argued that the claimed processes satisfied the machine-or-transformation test for Section 101 subject matter patentability articulated by the Federal Circuit in In re Bilski, 545 F.3d 943, 88 USPQ2d 1385 (Fed. Cir. 2008) (en banc) (77 PTCJ 4, 11/7/08).

The Federal Circuit in a 2009 ruling agreed, saying that “the methods of treatment claimed in the patents in suit squarely fall within the realm of patentable subject matter because they 'transform an article to a different state or thing,' and this transformation is 'central to the purpose of the claimed process,' ” quoting Bilski. The court also rejected the lower court's view that the disputed claims merely claim natural correlations and data-gathering steps.

Judge Alan D. Lourie wrote the Prometheus opinion, which was joined by then Chief Judge Paul R. Michel and Judge Ron Clark of the U.S. District Court for the Eastern District of Texas, sitting by designation.

Supreme Court's Vacates and Remands After Bilski.

Mayo filed a petition for writ of certiorari (79 PTCJ 10, 11/6/09), but in January 2009 (79 PTCJ 320, 1/22/10), the high court postponed its decision on the petition until it could address the Bilski case.

On June 28 in Bilski v. Kappos, the Supreme Court reaffirmed that process claims directed to an abstract idea are not patentable subject matter. 129 S.Ct. 2735, 95 USPQ2d 1001 (2010) (80 PTCJ 285, 7/2/10). But the court also made clear that the machine-or-transformation test is not the exclusive means of identifying the ineligibility of a patent claim for abstractness.

The next day, the high court granted certiorari in Prometheus, vacated the appellate court's panel decision, and remanded the case for reconsideration in light of the Bilski decision. Mayo Collaborative Services v. Prometheus Laboratories Inc., No. 09-490 (U.S., judgment vacated June 29, 2010) (80 PTCJ 288, 7/2/10).

The Federal Circuit gave the parties four weeks to file supplemental briefs, with a relatively short page limit, and limited to “addressing the effect of the Supreme Court's Bilski decision on the disposition of this case” (80 PTCJ 681, 9/24/10). The court said that no additional briefing and no oral argument were contemplated, clearly indicating that it was disinclined to argue again the issues addressed by the earlier panel.

With Michel now retired and Clark no longer available, a new panel was created, although Lourie wrote the opinion yet again, this time joined by Chief Judge Randall R. Rader and Judge William C. Bryson.

Claims Do Not Preempt All Uses of Correlations.

Lourie noted at the outset that the Bilski court did not reject the machine-or-transformation test, “but rather characterized the test as 'a useful and important clue, an investigative tool, for determining whether some claimed inventions are processes under §101.' ” In again holding the claims in the instant matter patent eligible, the Federal Circuit relied on that test in part.

But the court dealt first with Mayo's argument on remand that the Bilski decision required a different analysis in that it reaffirmed that preemption is the controlling standard under Section 101.

The Supreme Court has established that laws of nature, natural phenomena, and abstract ideas cannot be patented, Lourie said. While acknowledging that abstractness was the patentability exception at issue in Bilski, and that the natural phenomenon exclusion was at issue in the instant case, Lourie opted to apply the Supreme Court's Bilski analysis to the patent eligibility issue in this case.

“In light of the Supreme Court's decision in Bilski,” Lourie said, “patent eligibility in this case turns on whether Prometheus's asserted claims are drawn to a natural phenomenon, the patenting of which would entirely preempt its use as in Benson or Flook, or whether the claims are drawn only to a particular application of that phenomenon as in Diehr.”

The court was referring to a “trilogy” of cases on software patenting from 1972 to 1981. Gottschalk v. Benson, 409 U.S. 63, 175 USPQ 673 (1972); Parker v. Flook, 437 U.S. 584, 198 USPQ 193 (1978) (385 PTCJ A-1, D-1, 6/29/78); and Diamond v. Diehr, 450 U.S. 175, 209 USPQ 1 (1981) (519 PTCJ AA-1, D-1, 3/5/81). Patent eligibility was found only in the last of those three cases.

But Lourie explained that the earlier panel addressed the preemption issue in any case. “In our pre-Bilski decision in this case, we held not only that Prometheus's asserted claims recite transformative 'administering' and 'determining' steps, but also that Prometheus's claims are drawn not to a law of nature, but to a particular application of naturally occurring correlations, and accordingly do not preempt all uses of the recited correlations between metabolite levels and drug efficacy or toxicity,” he said.

“The Supreme Court's decision in Bilski did not undermine our preemption analysis of Prometheus's claims.”

Specifically, the court said, the application evident in the asserted claims in the instant case is in their recitation of “specific treatment steps, not just the correlations themselves. … [T]he claims do not preempt all uses of the natural correlations; they utilize them in a series of specific steps.”

Machine-or-Transformation Test Applied.

Proceeding to the transformation analysis, the court repeated almost verbatim the prior panel's review of the issue.

The court said of the claims, “The transformation is of the human body and of its components following the administration of a specific class of drugs and the various chemical and physical changes of the drugs' metabolites that enable their concentrations to be determined.”

Indeed, the court went further to define a type of claim that will always feature a transformation: “The asserted claims are in effect claims to methods of treatment, which are always transformative when one of a defined group of drugs is administered to the body to ameliorate the effects of an undesired condition.”

Lourie then split the discussion into details on the Prometheus claims that included an administering step and those that included only a determining step.

“When administering a drug such as AZA or 6-MP, the human body necessarily undergoes a transformation,” he said. “The drugs do not pass through the body untouched without affecting it.”

He also rejected Mayo's argument that the transformation is a natural process and thus is drawn to a natural phenomenon. “The fact that the change of the administered drug into its metabolites relies on natural processes does not disqualify the administering step from the realm of patentability. As Prometheus points out, quite literally every transformation of physical matter can be described as occurring according to natural processes and natural law.”

As to those claims that have no administering step, Lourie said that the determining step itself also involves a transformation. “Some form of manipulation, such as the high pressure liquid chromatography method specified in several of the asserted dependent claims or some other modification of the substances to be measured, is necessary to extract the metabolites from a bodily sample and determine their concentration,” he said.

Not Mere Data Gathering.

Nor are such steps mere data gathering for use the correlations, the court said, because the transformation in those steps “is central to the purpose of the claims. … The determining step, by working a chemical and physical transformation on physical substances, likewise sufficiently confines the patent monopoly, as required by the machine-or-transformation test.”

As such, the court said, the transformations described in the asserted claims are not “merely insignificant extra-solution activity,” which would be barred from patent eligibility under Flook. “While it is true that the administering and determining steps gather useful data, it is also clear that the presence of those two steps in the claimed processes is not 'merely' for the purpose of gathering data,” the court said. “Instead, the administering and determining steps are part of a treatment protocol, and they are transformative.”

The court specifically distinguished “prior cases that found asserted method claims to be unpatentable for claiming data-gathering steps and a fundamental principle,” such as In re Grams, 888 F.2d 835, 12 USPQ2d 1824 (Fed. Cir. 1989) (39 PTCJ 23, 11/9/89).

In Grams, the court said, “the essence of the claimed process was the mathematical algorithm, rather than any transformation of the tested individuals. … The claims did not require the performing of clinical tests on individuals that were transformative--and thus rendering the entire process patentable subject matter--because the tests were just to 'obtain data.' ”

In contrast, Prometheus's claims are part of treatment regimes for various diseases using thiopurine drugs, Lourie said. “As a result, the administering and determining steps are not insignificant extra-solution activity, and the claims are therefore not drawn merely to correlations between metabolite levels and toxicity or efficacy.”

Final Mental Steps Do Not Negate Eligibility.

Finally, the court addressed the district court's argument that the final step in the claims--providing a “warning” of toxicity or inefficacy without specifically requiring further action by the physician--are simply mental steps.

“A subsequent mental step does not, by itself, negate the transformative nature of prior steps,” the court said. And since no asserted claim consists only of mental steps, the court explained, “contrary to Mayo's assertions, a physician who only evaluates the result of the claimed methods, without carrying out the administering and/or determining steps that are present in all the claims, cannot infringe any claim that requires such steps.”

The addition of this last sentence was the only substantive change in the transformation analysis in the current opinion, compared to the earlier panel opinion.

The court likened the instant case to its predecessor court's decision in In re Abele, 684 F.2d 902, 214 USPQ 682 (C.C.P.A. 1982) (24 PTCJ 390 8/19/82). The Abele claims also featured antecedent steps that gathered data supplied to an algorithm, the court noted, and the “manifestly statutory subject matter” of the antecedent steps was not negated by the inclusion of an algorithm.

Quoting its own In re Bilski decision, the court said that “it is irrelevant that any individual step or limitation of such processes by itself would be unpatentable under §101.”

In the instant case, Lourie noted, “Although a physician is not required to make any upward or downward adjustment in dosage during the 'warning' step, the prior steps provide useful information for possible dosage adjustments to the method of treatment using thiopurine drugs for a particular subject.”

He concluded:  

Viewing the treatment methods as a whole, Prometheus has claimed therapeutic methods that determine the optimal dosage level for a course of treatment. In other words, when asked the critical question, “What did the applicant invent?,” Grams, 888 F.2d at 839 (citation omitted), the answer is a series of transformative steps that optimizes efficacy and reduces toxicity of a method of treatment for particular diseases using particular drugs.   






The claims asserted thus satisfy the preemption test and the transformation prong of the machine-or-transformation test, Lourie said in summary, again reversing the lower court's judgment of patent ineligibility under Section 101.

Richard P. Bress of Latham & Watkins, Washington, D.C., represented Prometheus. Jonathan E. Singer of Fish & Richardson, Minneapolis, represented Mayo.

By Tony Dutra  

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