Medical Diagnostics Claims Are Patentable Subject Matter

    By Kevin E. Noonan —

Over the past few years, Federal Circuit
decisions in In re Bilski and Classen Immunotherapeutics, Inc. v. Biogen Idec,
combined with Justice Breyer's dissent in Laboratory Corp. v. Metabolite Labs., Inc. ("LabCorp"), have created more than a frisson of anxiety in the
biotechnology and medical diagnostics community, due the apprehension that
medical diagnostics claims might generally be deemed not to be patent-eligible
subject matter under 35 U.S.C. § 101.  These fears may be alleviated to some degree by the decision today in Prometheus Laboratories, Inc. v. Mayo
Collaborative Services, where the Court held that a diagnostics claim
satisfies the machine-or-transformation test enunciated in Bilski.

The case relates to U.S. Patent Nos. 6,335,623 and
6,680,302, which were exclusively licensed by Prometheus.  Defendants Mayo Collaborative Services
and Mayo Clinic Rochester used the technology covered by these patents, until
Mayo unilaterally announced that it intended to use its own test internally and
to sell the test to other hospitals.  Prometheus brought suit and the District Court granted summary judgment
in Prometheus' favor that Mayo's test literally infringed claim 7 of the '623
patent.  All of the patent claims
relate to methods for identifying metabolites of thiopurine, a drug used to
treat various gastrointestinal disorders such as Crohn's disease and ulcerative
colitis.  Claim 1 of the '623
patent was cited in the Federal Circuit opinion as being 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 8×108 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 8×108 red blood cells indicates a need to decrease the amount of said
drug subsequently administered to said subject.

The District Court granted summary judgment in favor of the defendants that the
claims of the '623 and '302 patents were invalid under 35 U.S.C. § 101 for
failure to recite patent-eligible subject matter, stating that merely because
the inventors:

have framed the claims as "treatment
methods" does not make the claims patentable.  Indeed, "one can
reduce any process to a series of steps.  The question is what those steps
embody."  Lab. Corp. of
Am. Holdings v. Metabolite, Inc., 548 U.S. 124 (2006) (Breyer, J.,
dissenting from dismissal of certiorari) (emphasis in original); see also In re Grams, 888 F.2d
835, 839 (Fed. Cir. 1989) (explaining that the critical question is: "What
did applicants invent?") (quoting In
re Abele, 684 F.2d 902, 907 (C.C.P.A.1982)) . . .  [T]he "administering"
and "determining" steps are merely necessary data-gathering steps for
any use of the correlations.  However, an "unpatentable principle"
will not transform into a "patentable process" simply by adding
conventional method steps.  . . .  [The [wherein or] "warning"
step [in a mental step that] does not require that dosage be adjusted, or any
other action.  . . .  [I]t is the metabolite levels themselves that "warn"
the doctor that an adjustment in dosage may be required.

The District Court held that "the patents claimed the correlations
between certain thiopurine drug metabolite levels and therapeutic efficacy and
toxicity."  These
correlations were "natural phenomena" according to the District
Court, and thus unpatentable "because the correlations resulted from a
natural body process."  The
inventors of the '623 and '302 patents did not invent the correlation,
according to the lower court's
invalidity opinion, because the metabolites detected according to the patent
claims "are products of the natural metabolizing of thiopurine drug, and
the inventors merely observed the relationship between these naturally-produced
metabolites and therapeutic efficacy and toxicity."  Moreover, having determined that the
claims encompass the correlations themselves, the District Court held that the
claims "wholly preempt" the correlations.  The recited process steps, of administering a thiopurine
drug and determining the levels of thiopurine metabolites in a patient's blood,
were "merely necessary data-gathering steps," and the final step
constituting the "wherein" clause of claim 1 of the '623 patent (for
example) is merely a "mental step," according to the District Court,
since it did not recite any action mandating that a physician adjust the
administered dosage of the thiopurine drug.

The Federal
Circuit reversed, in an opinion by Judge Lourie joined by Chief Judge Michel
and the Honorable Ron Clark, District Judge of the U.S. District Court for the
Eastern District of Texas, sitting by designation.  The opinion cited as context the Supreme Court's expansive
definition of patentable subject matter in Diamond
v. Chakrabarty and its limits, as in Diamond v. Diehr and Gottschalk v. Benson,
as well as how methods were defined broadly by Congress under 35 U.S.C.
§ 100(b), but the analytical framework of the decision was the
machine-or-transformation test in In re
Bilski.  Citing Bilski, the Court framed the issue
before it as follows:

The key
issue for patentability, then, at least on the present facts, is whether a
claim is drawn to a fundamental principle or an application of a fundamental
principle.

The CAFC
turned to Bilski to address this "key
issue," with one additional caveat in guiding its application.  The Supreme Court, said Judge Lourie, "has
also made clear that the patent eligibility of a claim as a whole should not be
based on whether selected limitations constitute patent-eligible subject matter
. . . [I]t is "inappropriate to dissect the claims into old and new
elements and then to ignore the presence of the old elements in the analysis,"
citing Diehr, and that "it is
improper to consider whether a claimed element or step in a process is novel or
nonobvious, since such considerations are separate requirements set forth in 35
U.S.C. §§ 102 and 103, respectively," citing Bilski and Diehr.

Turning to
the claims at issue, the Federal Circuit held that the administering and determining
steps, dismissed by the District Court as constituting mere "necessary
data-gathering steps," were instead transformative and thus satisfy the
transformation prong of the Bilski machine-or-transformation (for convenience,
MOT) test.  The CAFC opined
that "[t]he transformation is of the human body following administration
of a drug and the various chemical and physical changes of the drug's
metabolites that enable their concentrations to be determined."  The Court found that these steps were
essentially "method of treatment" steps, "which are always transformative when a defined group of
drugs is administered to a body to alleviate the effects of an undesired
condition" (emphasis added).  A human body to
which drugs such as thiopurines are administered "necessarily undergoes a transformation," since "the
drugs do not pass through the body untouched without affecting it," which
the Court characterized as "the entire purpose of administering the drugs."  The Court rejected Mayo's contention
that the transformations are the result of "natural processes"
because "quite literally every transformation of physical matter can be
described as occurring according to natural processes and natural law."  But the transformation encompassed by
the administering step of the asserted claims are not "natural processes"
according to the Court:  "[i]t
is virtually self-evident that a process for a chemical or physical
transformation of physical objects or substances is patent-eligible
subject matter (emphasis in the original text).  Ironically noted in a footnote, the Court dismissed Justice Breyer's Metabolite
dissent, upon which the District Court "relied heavily on,"
summarily:  "[t]hat dissent is
not controlling law."

The
considerations that guided the panel in deciding that the administration steps
were transformative also apply to the metabolite-determining steps, according
to the Court, since metabolite levels "cannot be determined by mere
inspection."  The Court cited
in this regard Prometheus' expert, to the effect that "at the end of the
process [of metabolite-determining], the human blood sample is no longer human
blood; human tissue is no longer human tissue," i.e., these samples have
been transformed.

The Court's
opinion also rejected any characterization of the administering and
metabolite-determining steps as being "insignificant extra-solution
activity."  Failure to
recognize this was "the crucial error" made by the District Court,
according to Judge Lourie.  In this
analysis, the Federal Circuit applied the teachings of In re Grams, a case cited by the District Court in coming to its "extra-solution
activity" conclusion.  The
Federal Circuit distinguished the claims at issue here, which recite
patent-eligible subject matter, from the claims in Grams, which did not, because in Grams "the essence of the claimed process was [a] mathematical
algorithm, rather than any transformation of the tested individuals,"
being "merely an algorithm combined with a data gathering step."

The opinion
also asserted that, even if the "warning" step encompassed in the "wherein"
clause of claim 1 of the '623 patent was merely a mental step, it "does
not detract from patentability" (or, more properly,
patent-eligibility).  Looking at
the claim "as a whole":

The data
that the administering and determining steps provide for use in the mental
steps is 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.

And citing Bilski:

[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.

Finally, the Federal Circuit opined that the District Court erred in deciding that Prometheus'
asserted claims "wholly preempted" the use of correlations between
metabolites of thiopurine drugs and their toxicity and efficacy.  Rather, according to the Court, the
claims utilize, not preempt, the correlations of natural processes "in a
series of specific steps" that are patent-eligible subject matter
according to the statute, citing Diehr
and its analogous use of the Arrhenius equation for curing rubber (a
transformative step).  "Regardless,"
according to the Court, of this issue, satisfaction of the MOT test renders the
claims patent-eligible and thus "they do not preempt a fundamental
principle."

The decision
in the Prometheus case comes as at
least a temporary balm to the diagnostics industry, since similar claims in Classen had been summarily (and tersely)
rejected by the Federal Circuit as failing the Bilski MOT test (see Patent Docs post).  The Court's
recognition in this case of the transformative nature of method claim steps
reciting administering, or assaying, or determining, or immunizing thus
reconciles the application of the Court's Bilski
precedent with physical reality (not to mention common sense).  It also provides inventors and their
counsel with tools to adapt their diagnostic method claims to satisfy the test,
and precedent to defend patent-eligibility when challenged at the Patent Office
or in litigation.  Diagnostic
methods companies can now breathe a cautious sigh of relief, at least until the
Supreme Court decides Bilski later
this year.

Prometheus Laboratories, Inc. v. Mayo Collaborative
Services (Fed. Cir. 2009)
Panel: Chief
Judge Michel, Circuit Judge Lourie, and District Judge Clark
Opinion by
Circuit Judge Lourie