The Wisconsin Alumni Research Foundation (WARF) this week is celebrating a clean sweep in defending challenges to three patents on human and primate embryonic stem cells.
WARF, affiliated with the University of Wisconsin, holds three stem cell patents that in the view of many scientists impede the progress of research. Arising from work done in the 1990s by Wisconsin researcher James Thomson, the patents give WARF rights not only over technology used to derive stem cells but also over all human and primate ES cell populations in the United States that have been derived from fertilized embryos. Private companies must pay WARF hefty fees to do research with the cells, and university-based researchers, although only charged minimal fees, complain about the red tape involved in using the patented materials (Science, 13 April 2007, p. 182).
WARF's patents were first challenged in October 2006 by two citizens' groups, who claimed that the approach for getting primate ES cells was "obvious" and could have been successfully applied by anyone with the necessary resources. Last April, the U.S. Patent and Trademark Office (PTO) accorded the patents a preliminary rejection and agreed to reexamine them.
Last month, WARF began its string of legal victories when PTO upheld a 2006 patent that describes a method for cultivating pluripotent primate cells—-cells capable of turning into any cell type in the body--from fertilized embryos (Science, 7 March 2008, p. 1323). Then this week, PTO upheld two more patents, granted in 1998 and 2001, on nonhuman primate and human ES cells, respectively. In its latest decision, PTO rejects the argument that earlier work could have led directly to the cultivation of ES cells, asserting, for example, that a scientist who had successfully cultivated mouse ES cells didn't necessarily have the tools to repeat the feat with human material. "[I]n view of the unpredictability" associated with both the isolation and long-term sustainability of primate ES cells, wrote the examiners, "the present claims are not obvious. ..."
WARF welcomed the decisions. "We are heartened that after conducting an extremely thorough reexamination, the patent office reached the correct conclusion," said managing director Carl Gulbrandsen in a statement.
Opponents are looking to the next fight. Stem cell researcher Jeanne Loring of Scripps Research Institute in San Diego, California, who believes WARF patents are unjustified and obstruct research, says she is "surprised" at the PTO ruling. The groups that brought the complaint plan to appeal the 2006 patent on methodology to PTO's Board of Patent Appeals and Interferences. (Rulings are final on the other two.) "We have new information" on scientific work preceding Thomson's findings that will bolster the case, says Loring.
John Simpson of the Foundation for Taxpayer and Consumer Rights in Santa Monica, California, one of the groups that brought the complaint, says that in any event, "we think we've already won a major victory with these patent challenges." He points out that in the past year, WARF has eased up on proprietary claims in two areas: It no longer demands license fees from companies that do university-based research with its cells, and it revised its patent claims to apply only to ES cells derived from fertilized embryos.
This latter concession is crucial as the stem cell community moves wholesale into a new area: cultivation of so-called induced pluripotent stem cells, which are generated without eggs or embryos.