Magistrate Recommends That Defendants' Motion to Dismiss Be Allowed for Kit Claims and Denied for Method Claims
By Donald Zuhn --
Last month, in Oxford Immunotec Ltd. v. Qiagen, Inc., Magistrate Judge Donald L. Cabell of the U.S. District Court for the District of Massachusetts issued a report and recommendation that the joint motion to dismiss under Fed. R. Civ. P. 12(b)(6) filed by Defendants Qiagen, N.V.; Qiagen, Inc.; Quest Diagnostics, Inc.; and Laboratory Corporation of America Holdings ("Qiagen") be allowed in part and denied in part. Qiagen filed the motion to dismiss in response to a claim of infringement by Plaintiff Oxford Immunotec, Ltd. ("Oxford").
Oxford, which develops tests to diagnose and monitor patients with auto-immune diseases, had asserted six patents against Qiagen, asserting that Qiagen's development, use, and sale of a tuberculosis ("TB") test infringed the patents. The six patents -- U.S. Patent Nos. No. 7,632,646; 7,901,898; 8,216,795; 8,507,211; 8,617,821; and 9,005,902 -- relate to an in vitro method of diagnosing TB. Oxford's claimed method uses eight peptides from ESAT-6, a unique protein produced by Mycobacterium tuberculosis, the bacterium that causes TB. In Oxford's test, the eight ESAT-6 peptides are mixed with a test subject's blood and if T cells in the patient's blood produce IFN-γ, indicating that the patient has been exposed to M. tuberculosis, the patient is diagnosed with TB.
Prior to the development of Oxford's test, there were two standard methods for diagnosing TB: the Mantoux tuberculosis skin test (TST), which involves injecting a small amount of TB protein derivative into a patient's forearm and then observing the injection site 48 to 72 hours after the injection, and the sputum culture test, which involves collecting and culturing phlegm from a patient's upper respiratory tract to determine whether an infected patient actually has TB. Oxford's test is superior to the standard tests because it is faster, more convenient, less dependent on the administering physician's subjective judgment, and has a lower rate of false positives.
The patents asserted by Oxford contain both kit claims and method claims. Claim 7 of the '646 patent is representative of the kit claims at issue:
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 other asserted kit claims are claim 7 of the '898 patent and claim 17 of the '795 patent.
Claim 1 of the '211 is representative of the method claims at issue:
1. An assay for identifying Mycobacterium tuberculosis-specific immediate effector T cells in a subject, comprising: (a) providing a sample from said subject containing T cells; (b) exposing said T cells to an immunogenic amount of a peptide subfragment of ESAT-6 that contains a CD8+ epitope; and (c) prior to the generation of new immediate effector T cells in the sample, determining whether said T cells are activated by said peptide subfragment by measuring secretion of a cytokine from said T cells; wherein activation of said T cells identifies the presence of Mycobacterium tuberculosis-specific immediate effector T cells that were present in the original sample, in said subject.
The other asserted method claims are claim 1 of the '902 patent and claims 1 and 6 of the '821 patent.
Qiagen's motion to dismiss was based on the argument that Oxford's patents are directed to a law of nature, and therefore are directed to patent ineligible subject matter. With respect to the kit claims, Qiagen argued that the peptides used in the Oxford's claimed TB kit are naturally occurring (i.e., as part of ESAT-6) and therefore are products of nature. With respect to the method claims, Qiagen argued that Oxford's claimed methods do not involve an inventive concept because the steps recited in the claimed methods are inherent to practicing the natural law, and the methods are routine and conventional methods that were well known before the patents were issued.
Oxford countered that the peptide panel recited in the kit claims is not a product of nature because the peptides are synthetic and function differently from naturally occurring ESAT-6. Oxford also contended that its in vitro testing method was not a product of nature because in vitro testing is performed in the artificial conditions of a laboratory, and that its method is a substantial improvement over the prevailing skin test because it is faster and yields fewer false positive results.
Applying the two-step inquiry of Alice Corp. Pty. Ltd. v. CLS Bank Int'l, the Court first determined that the claims at issue are directed to a law of nature. In particular, the Court found that "the claims are drawn to ESAT-6, a naturally occurring protein, and the human immune system's naturally occurring response to ESAT-6." With respect to the kit claims, the Court noted that while it "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," adding that:
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.
With respect to the method claims, the Court determined that although the isolated peptides act differently than ESAT-6 in certain respects when the peptide panel kit is used to test for TB, "the end result of both reactions [whether in the body or in the in vitro test] is the same, the body's production of IFN- γ." The Court therefore concluded that Oxford's method claims are drawn to a law of nature, namely that T-cells that have previously been exposed to M. tuberculosis will excrete IFN-γ.
The Court therefore moved onto step two of the Alice inquiry. As explained by the Court:
Here, the plaintiff has discovered a law of nature -- namely which specific peptides in ESAT-6 are most likely to induce a recognition response by the T-cells of patients who have TB without creating false positive responses by the T-cells of those who have merely been vaccinated. The question therefore is whether plaintiff's process of combining its panel of selected peptides with a patient's blood in a test tube and then measuring cytokine production is an inventive process that adds enough to the natural law to bring the patent claims into the realm of patentable material.
Finding 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," the Court determined that "[t]here 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." The Court therefore recommended that Qiagen's motion to dismiss be allowed insofar as it seeks dismissal of the Oxford's claims for infringement of the kit claims, and denied in all other respects.
Report and Recommendation on Defendants' Joint Motion to Dismiss by Magistrate Judge Cabell