Stem Cell Patents—Reexamination/Litigation—The Last 5 Years

Abstract

U.S. patents directed to stem cell technologies have generated a high degree of interest and controversy. Many patents relating to stem cell technology have faced reexamination, litigation, or both. The U.S. Patent and Trademark Office (USPTO) recently upheld three Wisconsin Alumni Research Foundation (WARF) stem cell patents after reexamination requested by a third-party challenger in 2006. StemCells, Inc., and Neuralstem, Inc., both filed suits with respect to their patents related to neural stem cells. StemCells filed a suit on July 24, 2006, alleging infringement of its patents collectively referred to as "the neural stem cell patents," by Neuralstem, Inc. Neuralstem, Inc., filed a suit against StemCells, Inc., on May 7, 2008, alleging inequitable conduct during prosecution of StemCells' U.S. Patent No. 7,361,505. Both suits are yet to be decided. Pharmastem Therapeutics, Inc., had attempted to enforce its U.S. Patent Nos. 5,192,553 and 5,004,681, which resulted in invalidation of the patents in 2007. It remains to be seen what effect (if any) the recent increases in funding of stem research and the important U.S. Supreme Court decision on KSR v. Teleflex, Inc. (making it more difficult to establish nonobviousness of patentable subject matter) will have on challenges to stem cell patents.