In Celsis In Vitro, Inc. v. Cellzdirect, Inc., the Federal Circuit upheld the district court’s grant of a preliminary injunction based on a finding that Celsis had shown a likelihood of success against an obviousness challenge. While the opinion of the court (authored by Chief Judge Rader and joined by Judge Prost) did not strike me as unusual, Judge Gajarsa’s dissent certainly got my attention.
The Patent At Issue
The patent at issue is U.S. 7,604,929, directed to a method of producing multi-cryopreserved hepatocytes. Claim 1 reads:
1. A method of producing a desired preparation of multi-cryopreserved 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:
(A) subjecting hepatocytes that have been frozen and thawed to density gradient fractionation to separate viable hepatocytes from non-viable hepatocytes,
(B) recovering the separated viable hepatocytes, and
(C) 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.
As explained in Judge Rader’s opinion for the court, human hepatocytes are very useful in pharmaceutical research, but have a short lifespan and are fragile. Although cryopreservation of hepatocytes was known, it was not used because it typically results in the destruction of so many cells. Apparently, the claimed method was based on the discovery that greater than 70% of hepatocytes that survive a first freezing step will survive a subsequent freezing step.
The Obviousness Issue
As characterized by Judge Gajarsa, the asserted prior art showed that “all of the claimed elements were present in the prior art:”
(1) thawing cryopreserved hepatocytes;
(2) using density gradient fractionation to separate viable and non-viable cells; and
(3) refreezing and rethawing the hepatocytes.
Although the district court had found that “freezing and thawing hepatocytes a second time” was not known in the art, Judge Gajarsa did not agree with the other Federal Circuit judges that that was fatal to the obviousness challenge:
[O]viousness does not require that each element of the claimed invention must be present in the prior art. . . .
This “invention” is a “patent for a combination which only unites old elements with no change in their respective functions [and] obviously withdraws what already is known into the field of its monopoly.”
Although Judge Gajarsa cites Federal Circuit precedent for the proposition that “[r]epeating known steps to obtain a desired result is not inventive,” I am concerned that his analysis may not leave room for consideration of unexpected results. He acknowledges the possibility of unpredictability in the art, but cites Federal Circuit precedent for the proposition that “[o]bviousness cannot be avoided simply by a showing of some degree of unpredictability in the art so long as there was a reasonable probability of success.”
Influenced By The Procedural Posture?
Perhaps Judge Gajarsa was being particularly hard on the patent holder because of the procedural posture of the case on appeal—the review of a grant of a preliminary injunction. Indeed, his dissent refers to a preliminary injunction as an “extraordinary and drastic remedy.” He also criticizes the district court and the majority for holding the defendants to a “clear and convincing” standard of proof, rather than merely requiring them to raise “a substantial question as to . . . validity.” Still, patent holders with claims that might be analogized to the method claims here (e.g., that combine or repeat “known” steps), may want to develop a record that supports a finding of a high degree of unpredictability in the art and/or that shows that the claimed method achieves unexpected results.
