Geron Wins Favorable Final Judgment in Third Nuclear Transfer Patent Interference.

MENLO PARK, Calif. -- Geron Corporation (Nasdaq:GERN) announced today that the Board of Patent Appeals and Interferences of the U.S. Patent and Trademark Office has issued a final judgment in interference number 105,192 between Geron and Advanced Cell Technology Corporation ("ACT") of Worcester, Mass. In its ruling, the Board found all claims of U.S. Patent No. 6,235,970, which is licensed to ACT from the University of Massachusetts, to be unpatentable, effectively invalidating the patent. Previously, Geron received similarly favorable judgments in patent interferences with ACT and Infigen, Inc. of DeForest, Wis. Each of these interferences involved patent claims to nuclear transfer technology. Geron holds a worldwide license to this technology from the Roslin Institute.

"We are very pleased with the Board's ruling," said David J. Earp, J.D., Ph.D., Geron's chief patent counsel and senior vice president of business development. "This is the second ACT patent for nuclear transfer that we have successfully challenged. We believe that the Board's detailed and considered opinion further highlights the strength of Geron's nuclear transfer patent portfolio. The Board found all of the claims of the ACT patent to be unpatentable and rejected ACT's challenges to the Geron pending claims. The ruling opens the way for Geron to pursue additional claims that we will be able to make available to our licensees."

Nuclear transfer technology is broadly useful for the cloning of animals, and has been widely adopted and used to clone animal species including cattle, sheep, pigs, goats and cats. Geron has granted licenses under its nuclear transfer patent rights to several companies pursuing agricultural and biopharmaceutical cloning applications.

The patent claims in the present interference cover the use of nuclear transfer technology to create an embryo and then obtain and culture inner cell mass cells from the embryo, resulting in the production of embryonic stem cells. When applied to human cells, this process is referred to as "therapeutic cloning." This approach may be useful in creating specialized embryonic stem cell lines carrying genetic diseases for use in research and as models in drug discovery.

Additional Information

Nuclear Transfer

Nuclear transfer is a process in which a nucleus from a donor cell is inserted into an enucleated oocyte (egg), which is then used to produce an embryo. In animal applications, the embryo may then be implanted into a surrogate mother and give rise to a clone of the animal from which the original donor cell was taken. Geron obtained rights to the pioneering nuclear transfer technology, originally used to clone Dolly the sheep, when it acquired Roslin Bio-Med (now Geron Bio-Med) in 1999. As part of that acquisition, Geron obtained a worldwide license from the Roslin Institute to the nuclear transfer patent portfolio and assumed management of the patent applications. Under Geron's management, patents covering the technology have been issued in the United States, Europe, Australia and several other jurisdictions.

Geron requested that the U.S. Patent Office declare interferences between some of Geron's pending nuclear transfer patent applications and certain ACT patents because, in Geron's view, the technology covered by those patents was first invented at the Roslin Institute and was covered by the patent portfolio licensed to Geron.

Patent Interferences

An interference is a proceeding conducted by the Patent Office when two or more parties claim the same invention in patent filings. The Patent Office first determines, in a "preliminary motions" phase, whether the claims of either party are supported by the specification of its patent filing. In a second stage of the proceeding, the Patent Office may hold a "priority contest" to determine which party was the first to invent the subject matter of the claims. Under U.S. law, only the party that is the first to invent a new technology is entitled to claim it in a patent.

In the present interference, the Board entered final judgment after the preliminary motions phase and elected not to proceed to a priority contest. It did this having first found that ACT was not entitled to any of the claims of U.S. Patent No. 6,235,970, and then allowing ACT to introduce additional claims through a reissue application. Having considered the additional claims, the Board also ruled that ACT was not entitled to the claims in the reissue application, and entered final judgment on those claims. As Geron was the senior party in the interference (i.e., the Geron application was filed prior to that of ACT) the Board concluded that Geron was presumed to be entitled to a decision on priority and found that no purpose would be served by proceeding to a priority contest.

Therapeutic Cloning

Therapeutic cloning involves the application of nuclear transfer to human cells, and the production of human embryonic stem cell ("hESC") lines from the resultant embryo. A number of leading scientists have advocated the use of the technique to produce hESC lines carrying particular genetic diseases, facilitating research into cures for those diseases. Recently, regulatory agencies in the United Kingdom have granted licenses permitting therapeutic cloning to be used in medical research into cures for diabetes and motor neuron disease.

Geron was an early pioneer in the hESC field, and funded work that led to the first isolation of these cells. Geron is working to develop hESC-based cell therapies for a number of diseases, including spinal cord injury, diabetes and heart failure. The hESC lines that are used by Geron were not made by nuclear transfer, but rather were obtained from donated embryos left over from conventional in vitro fertilization procedures.

Related Patent Interferences

In January 2005, at the conclusion of a priority contest, the Board entered final judgment in interference number 104,746, covering the use of nuclear transfer technology for animal cloning. In that case the Board found all claims of the ACT / U. Mass. Patent No. 5,945,577 to be unpatentable, effectively invalidating that patent. ACT has appealed that decision to the U.S. District Court for the District of Columbia. The decision in interference number 105,192 is also appealable by ACT.

In January 2004, the Board entered final judgment in Geron's favor in a nuclear transfer patent interference with Infigen, Inc. of DeForest, Wisconsin, upholding the validity of all of Geron's claims and denying a patent to Infigen.

Geron is a biopharmaceutical company focused on developing and commercializing therapeutic and diagnostic products for cancer based on its telomerase technology, and cell-based therapeutics using its human embryonic stem cell technology.

This news release may contain forward-looking statements made pursuant to the to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that such forward-looking statements in this press release regarding Geron's patent portfolio involve risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products, reliance on collaborators and the maintenance of our intellectual property rights. Actual results may differ materially from the results anticipated in these forward-looking statements. Additional information on potential factors that could affect our results and other risks and uncertainties are detailed from time to time in Geron's periodic reports, including the quarterly report on Form 10-Q for the quarter ended September 30, 2004.