On July 5, the Federal Circuit found claims directed to cryopreservation methods for hepatocytes patent eligible under 35 USC §101, reversing the district court decision finding the claims invalid on motion for summary judgement. In reaching this conclusion, the court offered valuable guidance on the proper analysis of claims that involve natural products and provided comments on how the claims differed from previous Federal Circuit cases in the §101 arena.

The patent at issue was U.S. Patent No. 7,604,929. The court focused the analysis on claim 1, which defined the general cryopreservation process, and dependent claim 5 which described a preparation of hepatocytes from more than one source/donor (referred to as a pooled preparation).

Claim 1 of the ‘929 patent reads:

A method of producing a desired preparation of multicryopreserved hepatocytes, said hepatocytes, being capable of being frozen and thawed at least two times, and in which greater than 70% of the hepatocytes of said preparation are viable after the final thaw, said method comprising:

  • subjecting hepatocytes that have been frozen and thawed to density gradient fractionation to separate viable hepatocytes from non-viable hepatocytes,
  • recovering the separated viable hepatocytes, and
  • cryopreserving the recovered viable hepatocytes to thereby form said desired preparation of hepatocytes without requiring a density gradient step after thawing the hepatocytes for the second time, wherein the hepatocytes are not plated between the first and second cryopreservations and wherein greater than 70% of the hepatocytes of said preparation are viable after the final thaw.

Claim 5 further defined the composition of the preparation and reads:

The method of claim 1, wherein said preparation comprises a pooled preparation of hepatocytes of multiple sources.

The district court found all asserted claims invalid under §101. The district court discussed the limitations of the prior art methods, noting such methods led to poor recovery of viable cells and could not produce pooled preparations of cryopreserved cells due to the understanding in the art that hepatocytes could be frozen and thawed only one time and the short life span/scarcity of hepatocytes. The district court also recognized the inventive aspects of the claimed methods, noting the discovery by the inventors that a certain fraction of hepatocytes isolated after an initial freeze/thaw procedure could be re-frozen and still yield viable hepatocytes. As such, the methods enabled the production of pooled preparations of hepatocytes. Despite these findings, the district court found the claims ineligible under §101 after application of the two-step framework mandated by Alice, concluding in step one that the claims were directed to an ineligible law of nature (the discovery that hepatocytes are capable of surviving multiple free-thaw cycles) and concluding in step two that the additional steps in the method claims failed to provide the required “inventive concept” to transform the claims as the additional methods steps were well known.

The Federal Circuit disagreed with the district court’s analysis of both steps of the Alice framework. With regard to step one, the Federal Circuit found the panel characterized the claims as being directed to “a new and useful laboratory technique for preserving hepatocytes” and determined that such processes carried out to achieve “a new and useful end is precisely the type of claim that is eligible for patenting.” The Federal Circuit discussed the multiple steps required to carry out the claimed methods. The panel recognized that the discovery rested in part on the discovery of hepatocytes to survive multiple free-thaw cycles, but emphasized the inventors did not patent this idea in isolation; rather the inventors “employed their natural discovery to create new and improved ways of preserving hepatocyte cells for later use” (citing Myriad for the idea that the first to discover knowledge is in an excellent position to claim applications of that knowledge).

Processes carried out to achieve a new and useful end is precisely the type of claim that is eligible for patenting

The panel also distinguished prior case law (Genetic Technologies, Ariosa and In re BRCA), where the claims were “directed to” a patent-ineligible concept when the claims did nothing more than identify/observe the ineligible concept and did nothing more. The panel emphasized that the “natural ability of the subject matter to undergo the process does not make the claim directed to that natural ability.” If so, the court noted that such an interpretation would lead to the invalidity of numerous method claims (citing as one example, treating cancer with chemotherapy, which would be ineligible based on the cancer cells’ inability to survive such treatment). The court also distinguished Funk Brothers on the basis that the claims were not composition claims directed to the cryopreserved pool, but to methods of producing the pool, making the question of whether the cells behaved in their natural way or acquired a different use irrelevant.

In addition, the Federal Circuit defended its application of the two-step framework (holding the claims eligible at step one, as done previously in Enfish), stating that step one requires more than identification of a patent-ineligible concept, but requires determining what the claim is “directed to.” Applying the directed to inquiry, the panel found the claims directed to a new and useful technique of cryopreserving hepatocytes that “falls squarely outside those categories of inventions that are ‘directed to’ patent-ineligible concepts.”

The Federal Circuit went on to undertake the step two analysis and would have determined the claims were patent eligible at this stage as well. Importantly, the court applied rationale from the computer arts cases in making this determination, citing claims that “improve[] an existing technological process” are sufficient to “transform[] the process into an inventive application” of the patent-ineligible concept (citing Alice as well as referencing Mayo and Diehr). The court found the claimed methods provide significant improvements over the prior art, including improved viability and the production of pooled samples of hepatocytes. Regarding the use of well-known techniques in the claimed method for cryopreservation (which is normally fatal under the step two analysis), the panel determined that the inclusion of well-known steps in a method claim is not fatal (citing Diehr) and that in this case the act of repeating the freeze-thaw process itself was not well known. The fact that the inventor’s discovery of “something natural” led to the methods was not controlling. The court stated “To require something more at step two would be to discount the human ingenuity that comes from applying a natural discovery in a way that achieves a ‘new and useful end.’”

The court also addressed pre-emption at the end of the opinion, noting that the patent “does not lock up the natural law in its entirety” and noting that competitors had already engineered around the claims at issue.

This case does share many similarities with previous cases where the claims were found patent ineligible. One wonders how the concept of using a fraction of maternal plasma/serum (which the art had taught to discard) differs from performing an additional step in a known process (which the art taught as harmful) when the remainder of the steps in the recited methods are common in the art. In the present case, the court concluded that the inventive step (additional freeze/thaw cycles) in the claimed methods was in fact not known and as such this inventive contribution was enough to satisfy the “directed to” inquiry at step one of the framework and transform the claims at step two of the framework.

In summary, this opinion offers significant guidance to patent drafters in how to approach subject matter involving a natural process/phenomenon. Further, the Federal Circuit’s explicit recognition of improvements to an existing technological process offer the drafter the opportunity to creatively draft the specification and claims to take advantage of this exception.