In recent years the pursuit of diagnostic method patent claims in the U.S. has been a vexing and often futile quest for biotech patent practitioners and their clients alike. Following the Supreme Court’s landmark Mayo decision, the USPTO adopted a very tough stance toward diagnostic method claims, and has almost invariably rejected them, regardless of their form, as patent ineligible.

However, there may now be new hope for diagnostic method claims. The USPTO has just published a fourth set of subject matter eligibility examples, including two examples relating to diagnostic method claims (examples 29 and 31). These examples, particularly example 29, provide some useful insights/perspectives for drafting and amending diagnostic method claims, although there are some important caveats, as discussed below. What is striking is that the patent office appears to adopt a far more lenient view than previously of what claims are considered patent eligible. This article focuses on example 29, since it offers some surprising and significant outcomes for diagnostic method claims.

Diagnostic, theranostic, and treatment method claims in example 29

Example 29 provides a series of seven claims directed to diagnostic, “theranostic,” and treatment methods for “Julitis,” a condition relating to the hypothetical (but known) protein “JUL 1,” which the inventors have found to be present specifically in subjects suffering from Julitis. The claims are summarised below:

Claim 1 (eligible)

A two step “method for detecting JUL-1” which includes (1) obtaining a plasma sample, and (2) contacting the plasma sample with an anti-JUL-1 antibody and detecting binding between JUL-1 and the antibody.

Claim 2 (ineligible)

A “method of diagnosing julitis” containing steps identical to (1) and (2) above, plus step (3), which recites “diagnosing the patient with julitis when the presence of JUL-1 in the plasma sample is detected.”

Claim 3 (eligible)

A “method of diagnosing julitis” that is identical to claim 2 but for the use of a porcine anti-JUL-1 antibody.

Claim 4 (eligible)

A “method of diagnosing julitis” that is identical to claim 3 but for the use of mAb-D33 monoclonal anti-JUL-1 antibody developed by the inventors.

Claim 5 (eligible)

A “method of diagnosing and treating julitis in a patient” reciting detection and diagnosis steps identical to those in claim 2, but further including administration of vitamin D, a previously unknown treatment step.

Claim 6 (eligible)

A “method of diagnosing and treating julitis in a patient” identical in form to claim 5, but reciting administration of anti-tumour necrosis factor (TNF) antibodies, a conventional treatment step for julitis, rather than vitamin D.

Claim 7 (eligible)

A “method of treating a patient with julitis” by administering to the patient an effective amount of anti-TNF antibodies.

Analysis of the claims

As a reminder, the Patent Office has adopted a (conditional) three part “Mayo/Alice” test to determine claim eligibility as elaborated in its earlier guidance and examples, which is briefly summarized below:

  • Step 1 - Determine whether the claim is directed to a statutory category of patentable subject matter, i.e., a process, a composition, a machine, or manufacture. If yes, proceed to step 2A.
  • Step 2A - Determine whether the claim as a whole is directed to a judicial exception to patent eligibility, i.e.,: a natural law, a natural phenomenon, or an abstract idea. If not, the claim is patent-eligible. If yes, proceed to the third step (“2B”).
  • Step 2B - Determine whether any elements or combination of elements in the claim add “significantly more” beyond the mere judicial exception. If yes, the claim is patent eligible. If not, the claim is ineligible.

All of the above claims easily pass through step 1 of the "Mayo/Alice" test, as they are clearly drawn to a process. Things get more interesting for the subsequent steps.

  • For claim 1, the USPTO found that the recited steps “do not recite or describe any recognized judicial exception,” because it is focused on the process and not the product and so is found eligible.
  • In contrast, claim 2, introduces a diagnostic step that is deemed by the USPTO to be nothing more than a recitation of a “natural law” or a mental process/abstract idea, both judicial exceptions. Further, claim 2 did not pass the “significantly more” test (step 2B), as it recites only conventional/routine steps at a high level of generality and known in the art.
  • Claims 3 and 4, despite being considered drawn to a judicial exception (due to the diagnostic step), are held to be eligible because they contain elements that add “significantly more.” Which elements one might well ask? In claim 3, it is the use of porcine anti-JUL-1 antibodies in the detection step, and in claim 4, it is the use of the mAb-D33 monoclonal antibody developed by the inventors. The USPTO’s rationale for “significantly more” here is that the use of these specific reagents amounted to an “unconventional step” that met the significantly more threshold.
  • Although claim 5 recites the same detection and diagnostic steps of claim 2 and is directed to a judicial exception, it passes muster because it includes an unconventional treatment of administering vitamin D following the diagnosis step.
  • Claim 6 is identical to claim 5 except that anti-TNF antibodies are administered rather than vitamin D in the treatment step. Despite the fact that we are told that treatment of julitis with anti-TNF antibodies was routine/conventional, the patent office concludes that the recitation of a particular treatment, as opposed to any method of treating julitis, adds “meaningful limits on the use of the exception” and results in a combination of elements that, taken as a whole, amount to significantly more than the judicial exception.
  • Claim 7 is a straightforward method of treatment claim. This is consistent with the USPTO’s previous guidance around eligibility of method of treatment claims since it is clearly not directed to a judicial exception. What is surprising, perhaps, is that the claim appears directed to a method of treatment that was routine/conventional in the art. More on this point below.

Conclusions – the good, the bad, and the ugly

What general tips can be gleaned from the USPTO’s analysis of diagnostic method claims?

Where possible diagnostic claims should be drafted as method of detection claims without a diagnostic step, which would otherwise trigger the automatic conclusion that the claim is drawn to a judicial exception. This approach, of course, ignores whether such a claim, especially when reciting detection of a known protein, would actually be novel or non-obvious over the prior art. One possible strategy to overcome this potential prior art problem would be to include a step in which a sample is “collected from a patient identified as being at risk of [specific disease]”.

If a diagnostic step must be included in the claim, the claim should recite specific reagents, types of reagents, or detection methods that define an unconventional step. In their analysis of the above claims, the patent office certainly seems to have adopted a far more generous view than in the past of what it considers to be unconventional steps (e.g., the use of porcine antibodies or a specific monoclonal antibody).

If all else fails, the diagnostic or detection claim should also include a treatment step that recites the use of a specific treatment (or better yet, many types of specific treatments). Generally this is not desirable, as it presents a split infringement scenario that will likely render such claims difficult to enforce. However, some comfort might be found in the Federal Circuit’s recent Akamai decision, which held that in certain circumstances a method claim may be directly infringed even if steps are performed by different parties (e.g., a diagnostic step and a treatment step).

How does this fit with the Sequenom diagnostic case recently rejected by the Federal Circuit?

A major concern with the USPTO’s analysis of claim 1 (covering a “detection method”) is arguably in conflict with the Federal Circuit’s reasoning and decision in the recent Sequenom case relating to detection of cell free fetal DNA in material plasma. Indeed, several of the claims in Sequenom’s U.S. 6,258,340 patent were, like claim 1, two step detection method claims. In view of example 29, the USPTO would likely find many of Sequenom’s claims to be patent-eligible. Unfortunately, though, the court found Sequenom’s claims ineligible as purely directed to a natural phenomenon.. Importantly, given the profile of this case, Sequenom, together with a number of other interested parties have petitioned the Supreme Court to consider the case.

It should be noted that the new examples and analysis focus exclusively on patent-eligibility-not necessarily patentability of claims, an important distinction. More specifically, several of the claims analysed in example 29 appear to be unpatentable in view of the state of the art set out in example 29. For example, if JUL-1 was a “known” protein, it is hard to fathom how the detection method in claim 1 could be considered novel or non-obvious.

If nothing else, claim 7, drawn to a conventional, well known method of treating julitis, makes it crystal clear that the USPTO’s analysis is confined strictly to patent eligibility, apparently avoiding a more holistic approach that would give due consideration to the validity of diagnostic method claims under other sections of patent law. Notwithstanding these reservations, the latest guidance from the USPTO will be a most welcome and useful resource in countering patent eligibility rejections directed to diagnostic method claims.