This case returns to this court on remand from the Supreme Court for further consideration in light of the Court’s decision in
Bilski v. Kappos,
561 U.S. -,
Background
Prometheus is the sole and exclusive licensee of the '623 and '302 patents, which claim methods for determining the optimal *1350 dosage of thiopurine drugs used to treat gastrointestinal and non-gastrointestinal autoimmune diseases. These drugs include 6-mercaptopurine (“6-MP”) and azathiopurine (“AZA”), a pro-drug that upon administration to a patient converts to 6-MP, both of which are used to treat inflammatory bowel diseases (“IBD”) such as Crohn’s disease and ulcerative colitis. 6-MP is broken down by the body into various 6-MP metabolites, including 6-me-thylmercaptopurine (“6-MMP”) and 6-thioguanine (“6-TG”) and their nucleotides. 1
Although drugs such as 6-MP and AZA have been used for years to treat autoimmune diseases, non-responsiveness and drug toxicity may complicate treatment in some patients. Accordingly, the patents claim methods that seek to optimize therapeutic efficacy while minimizing toxic side effects. As written, the claimed methods typically include two separately lettered steps: (a) “administering” a drug that provides 6-TG to a subject, and (b) “determining” the levels of the drug’s metabolites, 6-TG and/or 6-MMP, in the subject. See, e.g., '623 patent claim 1. The measured metabolite levels are then compared to pre-determined metabolite levels, “wherein” the measured metabolite levels “indicate a need” to increase or decrease the level of drug to be administered so as to minimize toxicity and maximize treatment efficacy. See, e.g., id. In particular, according to the patents, a 6-TG level greater than about 400 picomole (“pmol”) per 800 million red blood cells or a 6-MMP level greater than about 7,000 pmol per 800 million red blood cells indicates that a downward adjustment in drug dosage may be required to avoid toxic side effects. See id. col.20 11.22, 54. Conversely, according to the patents, a 6-TG level of less than about 230 pmol per 800 million red blood cells indicates a need to increase the dosage to ensure therapeutic efficacy. See id. col.20 11.18-19.
Claim 1 of the '623 patent is representative of the independent claims asserted by Prometheus in this case:
1. 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-thiog-uanine in said subject having said immune-mediated gastrointestinal disorder,
wherein the level of 6-thioguanine less than about 230 pmol per 8x108 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 8x10 s red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.
'623 patent claim 1 (emphases added). Claim 1 of the '302 patent is substantially the same, with the addition of determining 6-MMP levels in addition to 6-TG levels. Claim 46 of the '623 patent dispenses with the “administering” step and claims only the “determining” step:
46. A method of optimizing therapeutic efficacy and reducing toxicity associated with treatment of an immune-mediated gastrointestinal disorder, comprising:
(a) determining the level of 6-thiog-uanine or 6-methylmercaptopurine in a subject administered a drug selected from the group consisting *1351 of 6-mercaptopurine, azathiop[u]rine, 6-thioguanine, and 6-methyl-mercaptoriboside, said subject having said immune-mediated gastrointestinal disorder,
wherein the level of 6-thioguanine less than about 230 pmol per 8x108 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 8x108 red blood cells or a level of 6-methylmereaptopurine greater than about 7000 pmol per 8x108 red blood cells indicates a need to decrease the amount of said drug subsequently administered to said subject.
'623 patent claim 46 (emphases added).
Prometheus marketed a PROMETHEUS Thiopurine Metabolites test (formerly known as the PRO-PredictRx® Metabolites test) that used the technology covered by the patents in suit. Mayo Collaborative Services and Mayo Clinic Rochester (collectively, “Mayo”) formerly purchased and used Prometheus’s test, but in 2004, Mayo announced that it intended to begin using internally at its clinics and selling to other hospitals its own test. Mayo’s test measured the same metabolites as Prometheus’s test, but Mayo’s test used different levels to determine toxicity of 6-TG and 6-MMP.
On June 15, 2004, Prometheus sued Mayo for infringement of the '623 and '302 patents. Prometheus asserted independent claims 1, 7, 22, 25, and 46 of the '623 patent and independent claim 1 of the '302 patent. Prometheus also asserted several dependent claims that require either that the measurement of the metabolites be performed using high pressure liquid chromatography, see '623 patent claims 6, 14, 24, 30, and 53, or that the thiopurine drug used be one of four specified drugs, see id. claims 32, 33, 35, and 36. Mayo rescinded its announcement shortly after Prometheus filed suit, and has yet to launch its test.
On November 22, 2005, the district court held on cross-motions for summary judgment that Mayo’s test literally infringed claim 7 of the '623 patent. Prometheus Labs., Inc. v. Mayo Collaborative Servs., No. 04-CV-1200, slip op. at 23 (S.D.Cal. Nov. 22, 2005) (Dkt. No. 227). In its opinion, the court construed “indicates a need” to mean “a warning that an adjustment in dosage may be required.” Id. at 18. This construction did not require doctors to adjust drug dosage if the metabolite level reached the specified levels; rather, the court found the two “wherein” phrases to mean “that when the identified metabolites reach the specified level, the doctor is warned or notified that a dosage adjustment may be required, if the doctor believes that is the proper procedure.” Id. at 17-18.
On January 29, 2007, Mayo filed a motion for summary judgment of invalidity, arguing that the patents in suit are invalid because they claim subject matter unpatentable under 35 U.S.C. § 101. Specifically, Mayo contended that the patents impermissibly claim natural phenomena — the correlations between, on the one hand, thiopurine drug metabolite levels and, on the other hand, efficacy and toxicity — and that the claims wholly preempt use of the natural phenomena.
On March 28, 2008, the district court granted Mayo’s motion for summary judgment of invalidity under § 101.
Prometheus Labs., Inc. v. Mayo Collaborative Servs.,
No. 04-CV-1200,
Second, the district court found that those correlations were natural phenomena, not patent-eligible inventions because the correlations resulted from a natural body process. The court stated that the inventors did not “invent” the claimed correlation; rather, “6-TG and 6-MMP are products of the natural metabolizing of thiopurine drugs, and the inventors merely observed the relationship between these naturally produced metabolites and therapeutic efficacy and toxicity.” Id. at *7. Finally, the court determined that “[because the claims cover the correlations themselves, it follows that the claims ‘wholly pre-empt’ the correlations.” Id. at *11. Thus, the court concluded that there was no genuine issue of material fact to be resolved as to whether the patents in suit were directed to statutory subject matter and found by clear and convincing evidence that the claims were invalid under § 101. Id. at *14. On May 16, 2008, the district court entered final judgment, and Prometheus timely appealed.
On appeal, we reversed and upheld the asserted claims’ validity under what was at the time this court’s “definitive test” for determining whether a process is patentable subject matter under § 101: the machine-or-transformation test.
Prometheus,
Following our decision in
Prometheus,
the Supreme Court issued a decision rejecting the machine-or-transformation test as the sole, definitive test for determining the patent eligibility of a process under § 101.
Bilski,
The Court then granted Mayo’s petition for certiorari, vacated our decision holding Prometheus’s method of treatment claims to cover patent-eligible subject matter under the machine-or-transformation test, and remanded the case for consideration'in light of the Court’s Bilski decision. On September 1, 2010, we requested that the parties simultaneously submit briefs, without further oral argument, to address the effect of the Supreme Court’s decision in Bilski on the disposition of this case. In view of this additional briefing and the Supreme Court’s guidance in Bilski, we again hold that Prometheus’s method claims recite patentable subject matter under § 101.
Discussion
We review the district court’s grant of summary judgment
de novo. AT&T Corp. v. Excel Commc’ns,
I.
The issue again before us is whether Prometheus’s method claims meet the requirements of § 101. The text of the statute provides that:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent thereof, subject to the conditions and requirements of this title.
35 U.S.C. § 101. The Supreme Court has consistently construed § 101 broadly. Most recently, in
Bilski,
the Court stated that by choosing expansive terms to specify four independent patent-eligible categories of inventions or discoveries— processes, machines, manufactures, and compositions of matter — and by modifying those terms with the comprehensive “any,” Congress plainly contemplated that § 101 would be given wide scope.
Yet, it is equally well-established that § 101, while broad, is not unlimited. “The Court’s precedents provide three specific exceptions to § 101’s broad patent-eligibility principles: ‘laws of nature, physical phenomena, and abstract ideas.’ ”
Id.
(quoting
Chakrabarty,
The Supreme Court has also established that while a law of nature, natural phenomenon, or abstract idea cannot be patented, “an
application
of a law of nature or mathematical formula to a known structure or process may well be deserving of patent protection.”
Bilski,
In light of the Supreme Court’s decision in
Bilski,
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. Bilski,
II.
We turn to the parties’ arguments on remand. Prometheus argues that neither the Supreme Court’s Bilski decision nor the Court’s GVR Order compels a different outcome on remand, and therefore we should again reverse the district court’s judgment of invalidity under § 101. Regarding Bilski, Prometheus contends that the Court held only that patents that do not satisfy the machine-or-transformation test are not necessarily impatentable and did not overrule the long-established view that claims that satisfy the machine-or-transformation test, like Prometheus’s, necessarily satisfy § 101. But regardless, Prometheus argues, its asserted claims not only satisfy the machine-or-transformation test, but also are not drawn to mere abstractions. Specifically, Prometheus argues that its asserted claims involve a particular transformation of a patient’s body and bodily sample and use particular machines to determine metabolite concentrations in a bodily sample (e.g., via high pressure liquid chromatography), thus satisfying either prong of the machine-or-transformation test. Prometheus further argues that its claims also involve an application of a law of nature, not the law itself, because they recite specific means of treating specific diseases using specific drugs, and therefore do not preempt the abstract idea of calibrating drug dosages to treat disease.
Mayo argues that the Supreme Court in
Bilski
reaffirmed that preemption is the controlling standard for § 101 under the Court’s
Benson, Flook,
and
Diehr
precedents and made clear that while a maehine-or-transformation test may inform the analysis, that test is not outcome determinative. And, according to Mayo, under the governing preemption standard, Prometheus’s claims are invalid because they preempt all practical use of naturally occurring correlations between metabolite levels and drug efficacy and any machine or transformation present in the claims is merely insignificant post-solution activity. Mayo also asserts that the carefully considered opinion of three Justices — allegedly cited approvingly by five Justices in
Bilski
— rejected Prometheus’s machine-or-transformation argument for nearly identical claims in
Laboratory Corp. of America Holdings v. Metabolite Laboratories, Inc.,
We disagree with Mayo. We do not think that either the Supreme Court’s
GVR Order
or the Court’s
Bilski
decision dictates a wholly different analysis or a different result on remand. 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. The Supreme Court’s decision in
Bilski
did not undermine our preemption analysis of Prometheus’s claims and it rejected the machine-or-transformation test only as a definitive test. The Court merely stated that “[t]he Court of Appeals incorrectly concluded that this Court has endorsed the machine-or-transformation test
as the exclusive test.”
III.
As before, we again hold that Prometheus’s asserted method claims recite a patent-eligible application of naturally occurring correlations between metabolite levels and efficacy or toxicity, and thus do not wholly preempt all uses of the recited correlations. As discussed below, the claims recite specific treatment steps, not just the correlations themselves. And the steps involve a particular application of the natural correlations: the treatment of a specific disease by administering specific drugs and measuring specific metabolites. As such, and contrary to Mayo’s assertions, the claims do not preempt all uses of the natural correlations; they utilize them in a series of specific steps.
See Diehr,
We similarly reaffirm that the treatment methods claimed in Prometheus’s patents in suit satisfy the transformation prong of the machine-or-transformation test, as they “transform an article into a different state or thing,” and this transformation is “central to the purpose of the claimed process.”
See Bilski,
Contrary to the district court and Mayo’s arguments on remand, we do not view the disputed claims as merely claiming natural correlations and data-gathering steps. 2 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 undesixed condition. More specifically, Prometheus here claimed methods for optimizing efficacy and reducing toxicity of treatment regimes for gastrointestinal and non-gastrointestinal autoimmune diseases that utilize drugs providing 6-TG by administering a drug to a subject. The invention’s purpose to treat the human body is made clear in the specification and the preambles of the asserted claims. See 623 patent col.2 11.16-19 (“The present invention provides a method of optimizing therapeutic efficacy of 6-mercaptopurine drug treatment of an immune-mediated gastrointestinal disorder.”); see, e.g., id. claim 1 (“A method of optimizing therapeutic efficacy for treatment of an immune-mediated gastrointestinal disorder, comprising ...”); id. claim 7 (“A method of reducing toxicity associated with treatment of an immune-mediated gastrointestinal disorder, comprising ... ”); id. claim 22 (“A method of optimizing therapeutic efficacy of treatment of a non-IBD autoimmune disease, comprising ... ”).
When administering a drug such as AZA or 6-MP, the human body necessarily undergoes a transformation. The drugs do not pass through the body untouched without affecting it. In fact, the transformation that occurs,
viz.,
the effect on the body after metabolizing the artificially administered drugs, is the entire purpose of administering these drugs: the drugs are administered to provide 6-TG, which is thought to be the drugs’ active metabolite in the treatment of disease, to a subject.
See
'623 patent col.l 11.49-51. 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. Transformations operate by natural principles. The transformation here, however, is the result of the physical administration of a drug to a subject to
transform
— i.e., treat — the subject, which is itself not a natural process. “It is virtually self-evident that a process for a chemical or physical transformation of
physical objects or substances
is patent-eligible subject matter.”
Bilski,
Not all of the asserted claims, however, contain the administering step. That omission, which occurs in claims 46 and 53 of the '623 patent, does not diminish the patentability of the claimed methods because we also hold that the determining step, which is present in each of the asserted claims, is transformative and central to the claimed methods. Determining the levels of 6-TG or 6-MMP in a subject necessarily 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. As stated by Prometheus’s expert, “at the end of the process, the human blood sample is no longer human blood; human tissue is no longer human tissue.” Decl. of Dr. Yves Théorêt ¶ 6, Prometheus Labs., Inc. v. Mayo Collaborative Servs., No. 04-CV-1200 (S.D.Cal. Mar. 29, 2007) (Dkt. No. 528-3). That is clearly a transformation. In fact, Mayo does not dispute that determining metabolite levels in the clinical samples taken from patients is transformative, but argues that this transformation is merely a necessary data-gathering step for use of the correlations. On the contrary, this transformation is central to the purpose of the claims, since the determining step is, like the administering step, a significant part of the claimed method. Measuring the levels of 6-TG and 6-MMP is what enables possible adjustments to thiopurine drug dosage to be detected for optimizing efficacy or reducing toxicity during a course of treatment. 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.
A further requirement for patent-eligibility is ensuring that the involvement of the transformation in Prometheus’s claimed process is “not merely insignificant extra-solution activity.”
Flook,
The crucial error the district court made in reaching the opposite conclusion was failing to recognize that the first two steps of the asserted claims are not merely data-gathering steps.
See Invalidity Opinion,
Given the integral involvement of the administering and determining steps in Prometheus’s therapeutic methods, this case is easily distinguishable from prior cases that found asserted method claims to be unpatentable for claiming data-gathering steps and a fundamental principle. Perhaps the case that offers the closest
*1358
comparison is
In re Grams,
Here, unlike the clinical test recited in
Grams,
the administering and determining steps in Prometheus’s claimed methods are not “merely” data-gathering steps or “insignificant extra-solution activity”; they are part of treatment regimes for various diseases using thiopurine drugs.
See Bilski,
We agree with the district court that the final “wherein” clauses are mental steps and thus not patent-eligible per se. However, although they alone are not patent-eligible, the claims are not simply to the mental steps. A subsequent mental step does not, by itself, negate the trans-formative nature of prior steps. Thus, when viewed in the proper context, the final step of providing a warning based on the results of the prior steps does not detract from the patentability of Prometheus’s claimed methods as a whole. The data that the administering and determining steps provide for use in the mental steps are obtained by steps well within the realm of patentable subject matter; the addition of the mental steps to the claimed methods thus does not remove the prior two steps from that realm. No claim in the Prometheus patents claims only mental steps. Therefore, 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.
This analysis is consistent with
In re Abele,
As we explained in Bilski,
*1359 [I]t is inappropriate to determine the patent eligibility of a claim as a whole based on whether selected limitations constitute patent-eligible subject matter. After all, even though a fundamental principle itself is not patent-eligible, processes incorporating a fundamental principle may be patent-eligible. Thus, it is irrelevant that any individual step or limitation of such processes by itself would be unpatentable under § 101.
In light of the foregoing analysis, we hold that Prometheus’s asserted method claims satisfy the preemption test as well as the transformation prong of the machine-or-transformation test.
Conclusion
For the foregoing reasons, we reverse the judgment of the district court and remand to the court with instructions to deny Mayo’s motion for summary judgment that the asserted claims are invalid under § 101.
REVERSED and REMANDED
Notes
. For the purposes of this opinion, "6-TG” encompasses 6-thioguanine nucleotides.
. Mayo, as did the district court, points to the opinion of three Justices dissenting from the dismissal of the grant of certiorari in
Lab. Corp.,
