, Dated

Press Release, Dated May 9, 2014

Geron Announces Record Date for

Distribution of Asterias Series A Common Stock

MENLO PARK, CA, May 9, 2014 Geron Corporation

(Nasdaq: GERN) today announced that it has set May 28, 2014 as the record date for the distribution to Geron stockholders of

the Series A Common Stock from Asterias Biotherapeutics, Inc. ( Asterias ) that Geron received in the previously

announced transaction to divest Geron s human embryonic stem cell assets, which closed on October 1, 2013. Geron expects

to complete by the end of July 2014 the distribution of the 6,537,779 shares of Asterias Series A common stock, to be made on

a pro rata basis to eligible Geron stockholders of record as of the close of business on the record date.

As announced previously, under the terms of the Asset Contribution

Agreement with BioTime, Inc. (NYSE: BTX) and Asterias,

as consideration for Geron s contribution to Asterias of its human embryonic stem cell assets, Geron received

6,537,779 shares of Asterias Series A common stock. Under the terms of the Asset Contribution

Agreement, Geron is contractually obligated to distribute the Asterias Series A common stock to Geron s

stockholders on a pro rata basis (the Series A Distribution ), other than with respect to fractional shares and

shares that would otherwise be

distributed to Geron stockholders residing in certain excluded jurisdictions, as explained

below. Only Geron stockholders as of the close of business on the May 28, 2014 record date and residing in the following

jurisdictions will receive shares in the Series A Distribution: the United States, Anguilla, Argentina,

Austria, Australia, Belgium, Bulgaria,

Canada, Cayman Island, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland,

France, Germany, Greece, Guam, Guernsey, Hong Kong, Hungary, India, Ireland, Israel, Italy, Japan, Korea, Latvia,

Lebanon, Liechtenstein, Luxembourg, Malta, Mexico, Monaco, Netherlands, Norway, Panama, Poland, Portugal,

Puerto Rico, Romania, Saudi Arabia, Singapore, Slovenia, Slovakia, Spain, Sweden, Switzerland, Taiwan, United

Arab Emirates, United Kingdom, Uruguay, British Virgin Island, and the U.S. Virgin Island (collectively, the

Distribution Jurisdictions ). All locations other than the Distribution Jurisdictions described above are

considered excluded jurisdictions. In

lieu of Geron distributing the Asterias Series A common stock in excluded jurisdictions, the Asterias

Series A common stock that Geron stockholders who reside in excluded jurisdictions would otherwise receive

will instead be sold for cash at prevailing market prices, and the net cash proceeds will be distributed ratably

to those stockholders. In addition, fractional shares will not be distributed in the Series A Distribution and will

instead be aggregated and sold for cash at prevailing market prices, and the net cash proceeds from the sales

will be distributed ratably to Geron stockholders who would otherwise be entitled to receive fractional shares.

Based on the number of shares of Geron common stock outstanding as

of April 25, 2014 (156,938,288 shares),

Geron estimates that for each share of Geron common stock held by a Geron stockholder, such Geron stockholder will

receive approximately 0.0417 of a share of Asterias Series A common stock in the Series A Distribution, or cash

in lieu thereof as described above. This estimated ratio equates to one whole share of Asterias Series A common stock

for every approximately 24 shares of Geron common stock. The actual pro rata ratio for the Series A Distribution

will be determined following the May 28, 2014 record date and may be different than the example given

above if there is any change in the number of shares of Geron common stock outstanding as of the record

Following completion of the Series A Distribution, Asterias is

contractually obligated under the Asset Contribution Agreement

to distribute on a pro rata basis to the holders of Asterias Series A common stock five-year

warrants to purchase eight million

shares of BioTime common stock at an exercise price of $5.00 per share (the BioTime Warrants ).

The BioTime Warrants were issued to Asterias by BioTime upon the close of the asset contribution

A registration statement on Form S-1 relating to the Series A Distribution

was previously prepared and filed by

Asterias with the Securities and Exchange Commission (the SEC ) and was declared effective by the SEC on May

2, 2014. The registration statement is

available on the SEC s website located at http://www.sec.gov. Copies of the final

prospectus relating to the Series A Distribution, when available, may be obtained from Robert Peabody, Chief Financial

Officer, Asterias Biotherapeutics, Inc., 230 Constitution Drive, Menlo Park, CA 94025. In addition, the final prospectus

relating to the Series A Distribution will be mailed to all Geron stockholders entitled to receive Asterias Series

A common stock in the Series A Distribution. The registration statement and prospectus prepared by Asterias describe

Asterias, including the risks of owning Asterias Series A common stock, and other details regarding the Series

A Distribution. As described therein, Asterias is a newly organized, development stage company in the start-up

phase, and has only recently commenced its primary product development programs. Geron stockholders as of the

record date should review the registration statement and prospectus for further information about Asterias and the

risks of owning Asterias Series A common stock.

Although Asterias plans to arrange for the trading of the Asterias

Series A common stock on the OTC Bulletin Board upon

the completion of the Series A Distribution, there is no existing public market for the Asterias Series A common

stock (or any other Asterias securities) or the BioTime Warrants, and there can be no assurance that an active

public market for either the Asterias Series A common stock or BioTime Warrants will ever develop. Geron stockholders

are cautioned that any value that Geron stockholders may ascribe to the Asterias Series A common stock

or the related BioTime Warrants is highly speculative.

The fair market value of Asterias Series A common stock and any cash

distributed to Geron stockholders in the Series

A Distribution will be treated as dividend income for U.S. federal income tax purposes for Geron stockholders

to the extent made out of Geron s current or accumulated earnings and profits (as determined under U.S.

federal income tax principles), if any. If any dividend income or gain were recognized by Geron stockholders in

connection with the distribution of the Asterias Series A common stock and cash, if any, or the anticipated distribution

by Asterias of the BioTime Warrants, as described above, Geron stockholders could incur U.S. federal income

taxes with respect to such distributions. The lack of an existing, or potentially any future, market for the

Asterias Series A common stock or the BioTime Warrants could limit or preclude the ability of Geron

stockholders to sell a sufficient

quantity of Asterias Series A common stock to satisfy such potential tax liabilities. As a result, Geron

stockholders may incur tax liabilities, but be unable to realize value from any Asterias Series A common stock

distributed by Geron and/or the BioTime Warrants to be distributed by Asterias. Because no further action is required

on the part of Geron stockholders to receive the Asterias Series A common stock and the related BioTime Warrants

in the distributions, if Geron stockholders do not want to receive the Asterias Series A common stock and the

related BioTime Warrants in the distributions (or cash in lieu thereof), the only recourse for Geron stockholders

will be to divest their Geron common stock prior to the May 28, 2014 record date. The foregoing

discussion is not and should not be construed to be tax advice to any Geron stockholder or any recipient of any

Asterias Series A common stock or BioTime Warrants. Holders of Geron common stock are urged to consult their tax

advisors with respect to the tax consequences of the distributions generally and in their particular circumstances,

including the applicability and effect of the alternative minimum tax and any state, local, foreign or other

tax laws and of changes in those laws.

This press release shall not constitute an offer to sell or

the solicitation of an offer to buy these securities, nor shall there

be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be

unlawful prior to the registration or qualification under the securities laws of any such state or

Geron is a clinical stage

biopharmaceutical company developing a first-in-class telomerase inhibitor, imetelstat,

myeloid malignancies. For more information about Geron, visit

Use of Forward-Looking

Except for the historical information contained herein, this press

release contains forward-looking