Embryonic stem cells, as their name suggests, are derived from embryos that develop from eggs that have been fertilized in vitro. Embryonic stem cells possess two properties that make them valuable for cell therapy. First, because embryonic stem cells are at a very early developmental stage (pluripotent), they retain the ability to become any one of the more than 200 cell types that make up the human body. A second feature of embryonic stem cells is their ability to remain in an undifferentiated state and to divide indefinitely.
Earlier, the USPTO announced it would re-examine patents covering embryonic stem cell discoveries made by University of Wisconsin researchers. The patents, US Pat. Nos. 5,843,780, 6,200,806, and 7,029,913, cover all embryonic stem cell research in the U.S. The USPTO granted each of the requests in September 2006 and rejected all claims of each of the patents on March 30, 2007.
In the Office Actions rejecting the claims, the examiners said the Wisconsin cells appeared to be either the same or obvious variations of cells described in previous patents issued to others or in scientific papers.
The USPTO smackdown really comes from two main prior art patent references:
(a) U.S. Pat. No. 5,166,065 (Williams et al.), which relates to the use of leukaemia inhibitory factor (LIF) in the maintenance and derivation of embryonic stem (ES) cells in culture. The ES cells are maintained and/or derived from animal embryos by culturing said cells or embryos in a culture medium containing an effective amount of LIF for a time and under conditions sufficient to maintain and/or derive said ES cells.
(b) U.S. Pat. No. 5,690,926 (Hogan), directed towards non-murine pluripotential cells that have the ability to be passaged in vitro for at least 20 passages and which differentiate in culture into a variety of tissues. The scope of the claimed cells includes any non-murine ES cells and particular claims are drawn to human pluripotential cells.
The request for reexamination was made by two nonprofits, the Foundation Taxpayer and Consumer Rights (FTCR) and the Public Patent Foundation (PUBPAT), who believe that the patents are impeding scientific progress and driving vital stem cell research overseas. They argue that the work done by University of Wisconsin researcher James Thomson to isolate stem cell lines was obvious in the light of previous scientific research, making the work unpatentable.
But, I don’t think anyone should go out and throw a party just yet. The patent office grants over 90 percent of the requests for reexamination and many of those patents are issued with substantially the same claim(s) as before reexamination. WARF, a nonprofit group that acts as UW’s tech transfer office, will have a chance to prove the cells are novel. And, if the claims are ultimately rejected, it can still appeal or narrow the claims. This could take years to resolve.
Still, a lot of money is at stake. WARF has made free licenses and cells available to more than 300 academic research groups but charges companies $75,000 to $400,000, depending on their size and the terms of the license. WARF also claims royalties from products produced using the patents.
WARF has said the patents apply to all human embryonic stem cells, no matter how derived, but had not slowed research. It said academic researchers were entitled to free licenses and had to pay only $500 for cells. The terms in general have been made less restrictive over time in response to complaints.
USPTO Office Actions:
If you are interested in more details of the ongoing dispute between California and Wisconsin, check out the coverage on the California Stem Cell Report.