Twice-Freezing Naturally-Occurring Liver Cells Can Be Patentable Under §101

July 12, 2016

New and useful laboratory techniques for preserving naturally-occurring cells is “precisely the type of claim that is eligible for patenting.”  That is the ruling by the Federal circuit in Rapid Litigation Management Ltd. V. Cellzdirect, Inc. [1], which overturned the District Court’s ruling of patent ineligibility.  In its opinion, the Federal Circuit applied the two-step process outlined in Alice[2] to a “natural discovery” that was then used to “create a new and improved way of preserving hepatocyte cells for later use.”

            As background, hepatocytes are a type of liver cell that are useful for testing, diagnostic and treatment purposes.  A previously-accepted drawback of hepatocyte use, according to the prevailing understanding relating to cryopreservation, was that their usefulness could not survive multiple freeze-thaw cycles.  However, the inventors of U.S. Patent No. 7,604,929 (the “patent”) unexpectedly discovered that a percentage of hepatocytes are capable of surviving and remaining viable after multiple freeze-thaw cycles and behaved like cells that were only once frozen.  The patent thus claimed a process comprising: (A) subjecting previously frozen and thawed cells to density gradient fractionation to separate viable cells from non-viable ones; (B) recovering the viable cells; and (C) refreezing the viable cells. 

            The Northern District of Illinois (“District Court”) found this patent to be invalid under 35 U.S.C. §101 because the discovery that hepatocytes are capable of surviving multiple freeze-thaw cycles was merely directed to an ineligible law of nature. And, the District Court concluded that this process lacked the requisite inventive concept because the inventors simply reapplied a well-understood freezing process twice.

            Under step one of the Alice test on appeal, however, the Federal Circuit explained that the patent actually was not simply an observation or detection of the ability of hepatocytes to survive multiple freeze-thaw cycles.  Rather, the patent was in fact directed to a laboratory process of preserving hepatocyte cells which achieved a notable advance over prior art techniques.  More clearly, it was the process of preservation deemed patent eligible, not the end product.  Indeed, the Federal Circuit argued that if the opposite were true, “no one would ever get a patent on cryopreservation or on any other innovative method that acts on something that is naturally occurring, simply because of the nature of the underlying subject matter.”

            The Federal Circuit then applied step two of the Alice test, concluding that the patent improves an existing technological process into an inventive application.  Specifically, although the individual steps of freezing and thawing were well known, a process of preserving hepatocytes by repeating those steps was not because the prevailing wisdom taught that cells could be frozen only once and then had to be discarded.  As such, repeating a step that the art taught should be performed only once was not considered routine or conventional even when the discovery of something natural led an inventor to do so.

            In addition, the Federal Circuit offered a pair of general thoughts regarding §101 eligibility.  First, patent eligibility does not hinge on ease of execution or obviousness of application because those are questions that are already examined under separate provisions of the Patent Act (i.e., §102 and 103).  Secondly, pre-emption reinforces §101 even though it is not test for patent-eligibility.  So, because the patent does not lock up the natural law in its entirety, and the infringer of the patent has already managed to engineer around the patent, the patent is clearly not directed to a patent-ineligible building block of human ingenuity.

            Accordingly, a new technique which involves something that is naturally occurring, even if aspects of the technique are independently well-known, can be patent eligible if, in its entirety, the technique goes against prevailing wisdom and provides an improvement in a new and useful way. 

Authored by Clark A.D. Wilson


[1] Rapid Litigation Management Ltd. V. Cellzdirect, Inc. (Fed. Cir. July 5, 2016).

[2] Alice Corp. v. CLS Bank Int’l, 134 S. Ct. (2014)