Celsis is the assignee of U.S. Patent No. 7,604,929 (filed Apr. 21, 2005) (“the ’929 patent”), which claims methods for preparing multi-cryopreserved hepatocytes (a type of liver cell). Claims 1 and 10 of the ’929 patent are on appeal:
1. A method of producing a desired preparation of multi-cryopreserved hepatocytes, said hepa-tocytes, 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 hepato-cytes, and
(C) cryopreserving the recovered viable hepa-tocytes to thereby form said desired preparation of hepatocytes without requir-ing 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.
10. A method of investigating in vitro drug metabolism comprising incubating hepatocytes of a multi-cryopreserved hepatocyte preparation in the presence of a xenobiotic, and determining the metabolic fate of the xenobiotic, or the affect of the xenobiotic on the hepatocytes or on an enzyme or metabolic activity thereof, wherein the hepatocytes have been frozen and thawed at least two times, and wherein greater than 70% of the hepatocytes of said preparation are viable without requiring a density gradient step after thawing the hepa-tocytes for the second time, wherein the hepa-tocytes are not plated between the first and second cryopreservations.
’929 patent col.19 l.56 – col.20 l.19, ll.49-59 (emphasis added to the disputed claim terms).
The specification of the ’929 patent explains that human hepatocytes are a useful laboratory model for evaluating drug candidates. Two problems, however, have limited their use. First, hepatocytes have a short lifespan which causes an inconsistent and limited supply. Specifically, the only sources of fresh hepatocytes are liver resections or non-transplantable livers of multi-organ donors. Due to this reliance on liver donation, fresh hepatocytes become available at unpredictable times. Researchers must wait until a liver donation and must often resume or begin research with little advance warning. This unpredictability hinders laboratory studies, which usually require a consistent source of supplies. This supply problem also limits research geographically to the region near the liver donor.
Judge(s): Randall Rader
Jurisdiction: U.S. Court of Appeals, Federal Circuit
Related Categories: Civil Remedies , Competition , Patent
|Circuit Court Judge(s)|
|Trial Court Judge(s)|
|Plaintiff Lawyer(s)||Plaintiff Law Firm(s)|
|Adam Kelly||Loeb & Loeb LLP|
|Julie Langdon||Loeb & Loeb LLP|
|Jprdan Sigale||Loeb & Loeb LLP|
|Defendant Lawyer(s)||Defendant Law Firm(s)|
|David Mangum||Parsons Behle & Latimer|
|Michael McCarthy||Parsons Behle & Latimer|
|Kevin Speirs||Parsons Behle & Latimer|
|Francis Wikstrom||Parsons Behle & Latimer|