| Completion of Enrollment in IMerge Phase 3 Expected in the Fourth Quarter      of 2021 Currently, 91% enrolled.
 
 Investor Day Planned for November
 
 Second Quarter and      Year to Date 2021 Financial Results Also Reported
 
 Conference Call      Scheduled for 4:30 p.m. ET Today
 
 FOSTER CITY, Calif.--(BUSINESS      WIRE)--August 16, 2021--
 
 Geron Corporation (Nasdaq: GERN), a      late-stage clinical biopharmaceutical company, today reported updates on      the IMerge Phase 3 trial in lower risk MDS and financial results for the      second quarter ended June 30, 2021. The Company will host a conference      call today at 4:30 p.m. ET to discuss these updates and current events. As      of June 30, 2021, the Company had $239.1 million in cash and marketable      securities. These financial resources, combined with expected future      non-dilutive funding under the current debt facility, are expected to fund      operations through the end of the first quarter of 2023.
 
 "We are      pleased with the achievement of 91% of the planned enrollment in IMerge      Phase 3 and expect the trial to be fully enrolled in the fourth quarter of      2021. In addition, the expected timing for top-line results in IMerge      Phase 3 has been accelerated by three months to the first quarter of      2023," said John A. Scarlett, M.D., Chairman and Chief Executive Officer.      "By confirming the results from IMerge Phase 2 in the current IMerge Phase      3, including the depth, breadth and durability of transfusion      independence, as well as the potential for disease modification, we expect      imetelstat to be a highly differentiated product in lower risk MDS in      comparison to drugs currently approved or in development today. We look      forward to bringing this innovative and important drug to lower risk MDS      patients, for whom there remain limited treatment options."
 
 Phase      3 Clinical Development
 
 Ongoing IMerge Phase 3 Clinical Trial in      Lower Risk Myelodysplastic Syndromes (LR MDS)
 
 As of August 12,      2021, the Company had achieved 91% of the planned enrollment in IMerge      Phase 3. The Company expects the trial to be fully enrolled in the fourth      quarter of 2021. In July 2021, a regularly scheduled Independent Data      Monitoring Committee (IDMC) meeting was held, and the IDMC recommended      that the trial continue without modification.
 
 The significantly      longer enrollment period caused by the COVID-19 pandemic has enabled a      longer follow-up period than previously projected. As a result, the      Company determined that the clinical cut-off date for the primary analysis      could occur three months earlier than originally planned, which the      Company expects will still provide a sufficiently mature data set to      assess the benefit-risk profile of imetelstat. The Company has shortened      the follow-up period after the last patient has been enrolled from 15      months to 12 months to enable the earlier clinical cut-off date for the      primary analysis. With the revised 12-month follow-up period for the      primary analysis, the Company now projects that top-line results from      IMerge Phase 3 will be available in the first quarter of 2023.
 
 For      further information about IMerge Phase 3, including enrollment criteria,      locations, and current status, please visit ClinicalTrials.gov/NCT02598661.
 
 Ongoing      IMpactMF Phase 3 Clinical Trial in Refractory Myelofibrosis (MF)
 
 The      Company plans to engage over 180 sites to participate in IMpactMF across      North America, South America, Europe, Australia, and Asia, of which 55      sites are currently open for enrollment. In the second quarter of 2021,      the first patient was dosed in IMpactMF. The Company continues to expect      the interim analysis to occur in 2024 and the final analysis in 2025.
 
 As      the only MF Phase 3 trial with overall survival (OS) as the primary      endpoint, the Company expects that success in this trial would provide      unequivocal proof of clinical benefit for patients, as well as further      evidence of disease-modifying activity with imetelstat treatment.
 
 For      further information about IMpactMF, including enrollment criteria,      locations, and current status, please visit ClinicalTrials.gov/NCT04576156.
 
 Investor      Day
 
 In November 2021, Geron plans to host a virtual event for      investors and analysts at which management and key opinion leaders will      discuss the following topics:
 
 -- Imetelstat's potential for disease      modification in LR MDS and refractory MF; -- Expected path to      commercializing imetelstat; -- Expansion of imetelstat development plans,      including new studies in additional indications; and -- An early discovery      program in second generation telomerase inhibitors.
 
 Recently      Reported Data in June 2021
 
 Poster Presentations at EHA2021 Virtual      Congress
 
 In June 2021, two poster presentations of imetelstat Phase      2 data were made at the European Hematology Association (EHA) Virtual      Congress. These presentations, available on Geron's website, further      support imetelstat's potentially differentiated approach to inhibiting      telomerase activity to target the malignant stem and progenitor cells in      the bone marrow responsible for the underlying hematologic myeloid      malignancies.
 
 The first poster presented new data and analyses of      the clinical efficacy of imetelstat in molecularly defined subtypes based      on cytogenetic and mutation profiles for patients in the IMerge Phase 2      clinical trial in lower risk MDS. As reported at previous EHA meetings,      meaningful and durable transfusion independence was observed in patients      from IMerge Phase 2, including transfusion-free periods greater than one      year, as well as substantial increases in hemoglobin. The new poster      presentation reported clinical responses across different cytogenetic and      molecularly defined categories, and these responses were independent of      mutation status or number of mutations. These data support the unique      telomerase inhibition mechanism of action of imetelstat and the potential      to target the malignant stem and progenitor cells of the underlying      disease. The Company is exploring these observations further in the      ongoing IMerge Phase 3.
 
 The second poster at EHA presented new      analyses of safety data from the IMbark Phase 2 trial in MF and the IMerge      Phase 2 trial in lower risk MDS to understand the characteristics of      hematologic and non-hematologic adverse events. These analyses highlighted      that the imetelstat-related cytopenias are short, reversable and with      limited clinical consequence when managed with the dose modification      guidelines in the protocols.
 
 Publication of IMbark Phase 2 Data in      Journal of Clinical Oncology
 
 Efficacy, safety and biomarker results      from the IMbark Phase 2 clinical trial were published in the Journal of      Clinical Oncology in a paper entitled "Randomized, Single-Blind,      Multicenter Phase II Study of Two Doses of Imetelstat in Relapsed or      Refractory Myelofibrosis." The publication, which is available online,      highlights the clinical benefits observed in the study, including symptom      response and OS, as well as evidence of disease-modifying activity from      biomarker and bone marrow fibrosis assessments.
 
 The trial design      for IMpactMF is intended to confirm the IMbark Phase 2 results and to      enable imetelstat to be a potential treatment option for MF patients who      no longer respond to currently approved JAK inhibitor therapies.      Currently, there is no approved drug for patients who fail or no longer      respond to JAK inhibitor therapies, and median survival for such MF      patients after discontinuation from ruxolitinib is only approximately 14      -- 16 months, representing a significant unmet medical need.
 
 Second      Quarter and Year-to-Date 2021 Results
 
 For the second quarter of      2021, the Company reported a net loss of $29.6 million, or $0.09 per      share, compared to $15.8 million, or $0.06 per share, for the comparable      2020 period. Net loss for the first six months of 2021 was $57.4 million,      or $0.18 per share, compared to $32.2 million, or $0.14 per share, for the      comparable 2020 period.
 
 Revenues for the three and six months ended      June 30, 2021 were $107,000 and $244,000, respectively, compared to      $43,000 and $95,000 for the comparable 2020 periods. Revenues in 2021 and      2020 primarily reflect estimated royalties from sales of cell-based      research products from the Company's divested stem cell assets. In      connection with the divestiture of Geron's human embryonic stem cell      assets, including intellectual property and proprietary technology, to      Lineage Cell Therapeutics, Inc. (formerly BioTime, Inc., which acquired      Asterias Biotherapeutics, Inc.) in 2013, Geron is entitled to receive      royalties on sales from certain research or commercial products utilizing      Geron's divested intellectual property.
 
 Total operating expenses      for the three and six months ended June 30, 2021 were $29.0 million and      $57.6 million, respectively, compared to $16.8 million and $33.7 million      for the comparable 2020 periods.
 
 Research and development expenses      for the three and six months ended June 30, 2021 were $21.9 million and      $43.1 million, respectively, compared to $10.8 million and $21.6 million      for the comparable 2020 periods. The increase in research and development      expenses for the three and six months ended June 30, 2021, compared to the      same periods in 2020, primarily reflects increased clinical development      costs associated with conducting two Phase 3 clinical trials, higher      imetelstat manufacturing costs for producing validation batches at      contract manufacturers to enable future production of imetelstat for      clinical and commercial purposes and higher personnel-related costs for      additional headcount.
 
 General and administrative expenses for the      three and six months ended June 30, 2021 were $7.1 million and $14.5      million, respectively, compared to $6.0 million and $12.1 million for the      comparable 2020 periods. The increase in general and administrative      expenses for the three and six months ended June 30, 2021, compared to the      same periods in 2020, primarily reflects new costs in connection with      pre-commercial activities, including modernizing the internal      infrastructure to support a commercial launch, and higher legal costs.
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