2012-02-02 22:32:00 -

MENLO PARK, Calif., February 2, 2012 - Geron Corporation (Nasdaq: GERN) today
announced that the company has completed enrollment in the randomized Phase 2
clinical trial of imetelstat, in combination with paclitaxel, in patients with
locally recurrent or metastatic breast cancer (MBC). Imetelstat is an inhibitor
of telomerase, which is upregulated in the vast majority of human tumors and is
required for tumor cell immortality and growth.

"This Phase 2 study enrolled in just over a year, ahead of our expectations,
attesting to the need for effective treatments for metastatic breast cancer and
driven by the interest among clinical investigators for compounds with novel
mechanisms of action against new targets," said Stephen M. Kelsey, M.D., Geron's
Executive Vice President, Head of R&D and Chief Medical Officer. "We continue to
expect to   report top-line results from this trial by the end of Q4 2012,
provided a sufficient number of progression events have accrued in order to
estimate the progression-free survival for patients receiving imetelstat in
addition to standard of care. Currently, we believe an improvement of
approximately three months in PFS over standard of care, assuming a
representative patient population was enrolled, would be consistent with a
clinical benefit."

Trial Design

The Phase 2 trial (B014), which was initiated in December 2010, is an open
label, multi-center, randomized (1:1) study of the efficacy and safety of
treatment with imetelstat plus paclitaxel versus paclitaxel alone in patients
with locally recurrent or MBC who have not received chemotherapy or have
received one non-taxane based chemotherapy for MBC.

A total of 166 patients were enrolled in the study. The protocol allowed up to
30% of enrolled patients in both arms of the study to receive bevacizumab based
on the investigator's decision and drug availability to the patient. Patients in
the trial are stratified according to the use of bevacizumab in combination with
paclitaxel and line of therapy (first line versus second line).

The primary efficacy endpoint for this Phase 2 trial is an estimation of
progression-free survival (PFS) for patients receiving imetelstat in addition to
paclitaxel. Secondary efficacy endpoints are objective response rate and
clinical benefit rate of imetelstat when added to paclitaxel. Safety and
tolerability are also being assessed. Top-line results are expected to be
available by the end of the fourth quarter of 2012, provided that a sufficient
number of progression events have occurred.

Rationale for the Study

Breast cancer progression and relapse are believed to be driven by cancer
progenitor cells expressing high levels of telomerase. Standard chemotherapy and
other conventional agents are effective against actively proliferating bulk
tumor cells, but do not target cancer progenitor cells. As a result, after
initial responses to standard treatments, tumors may re-grow due to
proliferation and differentiation of progenitor cells, causing relapse of the
disease.

Imetelstat has been shown, in preclinical models, to inhibit breast cancer
progenitor cells as well as tumor growth and metastasis. By inhibiting breast
cancer progenitor cells, the use of imetelstat in combination with standard
debulking chemotherapy, such as paclitaxel, may increase the duration of
response and PFS in patients. In addition, previously published in vitro studies
showed that imetelstat synergizes with paclitaxel in inhibiting the growth of
breast cancer cells.

Phase 1 studies using imetelstat documented the drug's safety profile. Toxicity
was predictable, manageable and reversible. Cytopenias (thrombocytopenia and
neutropenia) were dose-limiting.

The Phase 2 dose and dosing schedule of 300 mg/m2 of imetelstat on day one of a
21 day treatment cycle were selected to achieve exposures to imetelstat that
exceed the levels that have been associated with efficacy in xenograft models of
human cancers, while minimizing hematological toxicities.

About Imetelstat

Imetelstat (GRN163L) is a potent and specific inhibitor of telomerase currently
in clinical trials in solid tumor and hematological malignancies. This first-in-
class compound is a specially designed and modified short oligonucleotide, which
targets and binds directly and with high affinity to the active site of
telomerase. Proprietary oligonucleotide chemistry improves binding affinity and
stability in plasma and tissues. A lipid modification enables cellular and
tissue penetration and biodistribution.

About Breast Cancer

Breast cancer is the most frequently diagnosed cancer in women worldwide. The
highest incidence of breast cancer is in the United States, where, in 2011, an
estimated 230,480 new cases were projected, and an estimated 39,970 people were
expected to die of the disease (American Cancer Society, Cancer Facts and
Figures 2011).

Significant advances in the treatment of breast cancer have improved outcomes
for many patients. However, better therapies and novel approaches are needed to
impact outcomes for many others, such as those with metastatic disease.

About Geron

Geron is a biopharmaceutical company developing first-in-class cancer
therapeutics. Imetelstat, the company's lead telomerase inhibitor, is currently
being evaluated in four Phase 2 clinical trials for the following indications:
non-small cell lung cancer, breast cancer, essential thrombocythemia and
multiple myeloma. GRN1005, an LRP-directed peptide-drug conjugate, is being
evaluated in two Phase 2 clinical trials, one for brain metastases arising from
non-small cell lung cancer and the other for brain metastases arising from
breast cancer. For more information about the company, visit www.geron.com.

Forward Looking Statements

Except for the historical information contained herein, this press release
contains forward-looking statements made pursuant to the "safe harbor"
provisions of the Private Securities Litigation Reform Act of 1995. Investors
are cautioned that statements in this press release regarding: Geron's beliefs,
plans or expectations for or of: dates to obtain top-line data from the Phase 2
oncology clinical trial of imetelstat and clinical success of imetelstat,
including without limitation that three months in PFS over standard-of-care
would be consistent with a clinical benefit, constitute forward-looking
statements. These statements involve risks and uncertainties that can cause
actual results to differ materially from those in such forward-looking
statements. These risks and uncertainties, include, without limitation: (a)
regarding dates for the availability of top-line data - delays caused by
insufficiency of progression events accruing, institutional review boards or
regulatory agencies, shortage of supply, dependence on clinical trial
collaborators, or safety issues; (b) regarding the clinical success of
imetelstat - those risks and uncertainties inherent in the development of
potential therapeutic products, including without limitation, successful
clinical trial results and that neither the FDA nor a competitor's product
candidate or product set the standard for clinical benefit at greater than three
months in PFS over standard-of-care. Additional information and factors that
could cause actual results to differ materially from those in the forward-
looking statements are contained in Geron's periodic reports filed with the
Securities and Exchange Commission under the heading "Risk Factors," including
the Annual Report on Form 10-K for the year ended December 31, 2010 and
quarterly report on Form 10-Q for the quarter ended September 30, 2011. Undue
reliance should not be placed on forward-looking statements, which speak only as
of the date they are made, and the facts and assumptions underlying the forward-
looking statements may change. Except as required by law, Geron disclaims any
obligation to update these forward-looking statements to reflect future
information, events or circumstances.

CONTACT:

Anna Krassowska, Ph.D.
Investor and Media Relations
650-473-7765
investor@geron.com
media@geron.com

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