Prometheus v. Mayo: A win for personalized medicine

Intellectual Property and Technology News


The Federal Circuit’s highly anticipated decision in Prometheus v. Mayo1 may significantly affect approaches to life science method patents, including methods critical to the development of personalized medicine.


Although the court’s decision, issued in September 2009, offers some strategic guidance to those enforcing or defending against patents in this area, important questions still remain regarding the application of Section 101 to life science method patents.


How we got here


The Prometheus decision drew considerable amici interest from many important players in the biotech community – prompted by a series of opinions leading up to Prometheus. In Laboratory Corp. of American Holdingsv. Metabolite Labs., Inc.,2 Justice Stephen Breyer drafted a dissenting opinion analyzing the validity of a patent claiming a method for diagnosing deficiencies of two vitamins by measuring the level of an amino acid, homocysteine.3 Justice Breyer stated that the patent claim at issue should be invalid under Section 101 because the claimed method “embod[ies] only the correlation between homocysteine and vitamin deficienc[ies] that the researchers uncovered.” Subsequently, in Classen Immunotherapies, Inc. v. Biogen Idec,4 the Federal Circuit summarily affirmed an order granting summary judgment that held similarly focused patents were invalid under 35 U.S.C. § 101. The patent claims in Classen were directed to methods for immunizing a treatment group and comparing the incidence of chronic immune-mediated disorders in the treatment group to a control group.5 The Federal Circuit’s opinion simply stated that the patent claims at issue did not satisfy the machine-or-transformation test set forth in In re Bilski.6 The court did not provide any rationale or discussion, leaving the industry to wonder whether method of treatment or diagnostic claims could survive a Section 101 challenge under the Bilski test.7


The Prometheus decision


Prometheus involved patent claims directed to a method of treating an immune-mediated gastrointestinal disorder by administering a drug and then determining appropriate dosage by measuring changes in the patient’s drug metabolite levels.8 The district court granted summary judgment of invalidity under Section 101, finding the claims invalid for claiming a natural phenomenon: the correlation between drug metabolite levels and therapeutic efficacy.9 The Federal Circuit reversed, holding the drug-administering step of the claims is a necessary transformative step that satisfies the Bilski test. “When administering a drug . . . the human body necessarily undergoes a transformation.”10 The court also held that the step of determining drug metabolite levels satisfied the transformation prong of the Bilski test separate and apart from the method of treatment. “Some form of manipulation . . . is necessary to extract the metabolites from a bodily sample and determine their concentration . . . . That is clearly a transformation.”11


The decision in Prometheus is important for at least two reasons. First, it draws a bright

line with respect to drug method-of-treatment claims by holding that such claims are “always transformative” when a defined drug or group of drugs is administered to treat an undesired condition.12 Second, the decision bodes well for diagnostic method claims because the court found the step of determining drug metabolite levels to be patentable even for those claims that lacked the drug-administering step. The Federal Circuit disagreed with the district court’s finding that the determining step was merely a “datagathering” step for using the correlation between drug metabolite levels and efficacy.13 This is a critical development in view of the court’s previous decision in Classen, where similar diagnostic claims were found invalid.


Where we go from here


There are at least three crucial questions going forward. First, does the Prometheus decision represent a shift in the Federal Circuit’s view of diagnostic process claims in Classen, or is the Prometheus holding fact specific? The patent claims in the two cases are similar, but the court’s summary decision in Classen leaves certain questions: For example, is there a principled distinction between the two cases, or should the court’s non-precedential opinion in Classen simply be disregarded? Second, does the machine portion of the Bilski machine-or-transformation test apply to biotechnology method patents, where the “machines” are often less tangible items like synthesized molecules or biomarkers? In Prometheus, the court declined to address that issue. Third, what will the Supreme Court do in Bilski? In light of Justice Breyer’s opinion in Laboratory Corp., it is not clear whether the Court’s application of the machine-or-transformation test will be less friendly to life science method patents, or whether the Court will articulate an entirely new test that could have critical consequences for biotechnology patents.


Until these questions are answered, the Prometheus decision offers some strategic guidance to litigants enforcing or defending against life science method patents. The key issue in analyzing any such claims under Section 101 will be whether the claimed subject matter effects a patentable transformation. As a result, parties in litigation should plan to develop fact and expert evidence early in a case regarding any relevant transformations that occur as a result of the claimed process – what transformations occur, how those transformations take place and why the transformations are important to achieve the claimed result. This is particularly true for diagnostic methods that do not also include a method of treatment, where a transformation may be more difficult to observe or prove.




1. Prometheus Labs., Inc. v. Mayo Collaborative Servs., 581 F.3d 1336 (Fed. Cir. 2009).

2. Lab. Corp. of Am. Holdings v. Metabolite Labs., Inc., 548 U.S. 124 (2006).

3. The dissenting opinion was issued in a per curiam opinion dismissing writ of certiorari as improvidently granted, not a substantive majority opinion on the merits of the patent issues.

4. Classen Immunotherapies, Inc. v. Biogen Idec, 304 Fed. App’x 866, Nos. 2006-1634, 2006-1649, 2008 WL 5273107, at *1 (Fed. Cir. Dec. 19, 2008).

5. Classen Immunotherapies, Inc. v. Biogen Idec, No. WDQ-04-2607, 2006 WL 6161856 (D. Md. Aug. 16, 2006).

6. In re Bilski, 545 F.3d 943 (Fed. Cir. 2008), cert. granted, 129 S. Ct. 2735 (2009).

7. Classen Immunotherapies, 304 F. App’x at 867.

8. 581 F.3d at 1339-40.

9. Id. at 1340-41.

10. Id. at 1346.

11. Id. at 1347.

12. Id. at 1346.

13. Id.