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Oxford Immunotec, Ltd. v. Qiagen, Inc.

Representative Claim(s)

The ‘646 Patent

7. A kit for diagnosing infection in a human host by, or exposure of a human host to, a mycobacterium that expresses ESAT-6, comprising a panel of eight peptides represented by SEQ ID NOS: 1 to 8.

The ‘902 Patent

1. A method of in vitro diagnosis of Mycobacterium tuberculosis infection in a host, comprising (a) keeping a population of T cells isolated from said host in contact with a peptide panel comprising one or more epitopes contained within one or more peptides selected from the group consisting of: SEQ ID NO: 1, peptide SEQ ID NO: 2, peptide SEQ ID NO: 3, peptide SEQ ID NO: 4, peptide SEQ ID NO: 5, peptide SEQ ID NO: 6, peptide SEQ ID NO: 7, and peptide SEQ ID NO: 8, and (b) detecting a recognition response by the T cells to the peptide panel.


Motion to Dismiss based on inevitable finding of non-patentable subject matter.  A Magistrate Judge previously found that the kit claims were invalid under § 101, but that the method claims not clearly invalid and could thus not be dismissed prior to fact finding.

Exception Categories: Law of Nature, Natural Phenomenon

The kit and method claims were separately addressed.  When addressing the kit claims, the Magistrate Judge discussed whether the peptides in the kits were naturally-occurring.  In doing so, the Magistrate Judge implicated the law of nature exception, although it should properly have implicated the natural phenomenon exception (or the “product of nature” exception as the Supreme Court referred to it in Myriad).

Kit claims

The Magistrate Judge held that, “while the Court appreciates that isolated peptides perform differently than peptides contained in an intact ESAT-6 strand, the Court does not find this fact significant to its analysis. The inquiry at step one of the Mayo analysis is whether the peptides are drawn to patent ineligible subject matter. Applied here, the question is whether the peptides exist in nature or whether, instead, they have been changed from their natural state. It is undisputed that the peptides have not been changed beyond the act of isolation. The Court thus finds that the isolated peptides are products of nature.”

As such, the Magistrate Judge did not proceed to second step of the Mayo two-part analytical framework.

Method claims

The Magistrate Judge held that, “when the peptide panel kit is used to test for TB infection, the isolated peptides do act differently than ESAT-6 in certain respects. Specifically, the isolated peptides are able to obtain a response from CD4 T-cells and CD8 T-cells, while ESAT-6 only obtains a response from CD4 T-cells. The isolated peptides are also capable of binding to the T-cells without an antigen-presenting cell or MHC cells, both of which are required when the reaction occurs in the body.”

“Despite these differences in how the immune system reaction occurs, however, the end result of both reactions is the same, the body’s production of IFN-γ. The Court thus concludes that the plaintiff’s method claims are drawn to a law of nature: T-cells that have previously been exposed to M. tuberculosis will excrete IFN-γ.”

Significantly More: Yes

Kit claims

The District Judge agreed with the Magistrate Judge’s holding that, “the plaintiff’s complaint alleges that Oxford’s patented inventions provide a ‘faster and more reliable method of diagnosing TB infection,’ than the conventional means available at the time of the invention, the TST and sputum culture. (Dkt. No. 1). The patents-in-suit state that the only TB tests in ‘general use’ before the plaintiff’s invention were the TST and sputum culture. (Id.). Accepting these allegations as true, the Court finds that the patented invention improves on existing methods for diagnosing TB by making diagnosis more convenient, less dependent on a physician’s subjective interpretation of results, and more accurate. There is thus a plausible reading of the patents by which one could find that the plaintiff’s in vitro tuberculosis test involves an inventive concept.”

“At this early juncture, the Court concludes that the in vitro aspect of the plaintiff’s tuberculosis test is an “inventive concept” because it improves on prior methods of detecting tuberculosis infection. It follows that the method claims, which describe the in vitro test, are potentially drawn to patentable subject matter.”

Method claims

The District Judge disagreed with the Magistrate Judge’s holding that, “the kit claims only describe the peptide panel itself and do not involve the ‘inventive concept’ of an in vitro test, and thus are not drawn to patentable subject matter.”

Relying on testimony from the plaintiff’s expert and on the fact-based analysis that would be required to determine whether the claimed peptides are naturally occurring, Judge Gorton explained, “This Court rejected that finding [in a previous proceeding] because, taking the plaintiff’s allegations as true, the claimed peptides were chemically different than the naturally occurring amino acids in the ESAT-6 protein and that purportedly results in the peptides behaving differently in plaintiff’s in vitro tests than would the amino acids in the ESAT-6 protein.”  Thus, the kit claims met the minimum threshold to proceed past the motion to dismiss stage.