Geron Presentation

Piper Jaffray Healthcare Conference

John Scarlett, M.D. President and CEO, Geron Corporation November 2018 Forward-Looking Statements

Except for statements of historical fact, the statements contained in this presentation are forward-looking statements made pursuant to the Safe Harbor provisions of the Private Securities Litigation Reform Act of 1995. These include, without limitation, statements regarding the expectations, plans, timelines and prospects for imetelstat and Geron, including without limitation: (i) that the imetelstat IND transfers from Janssen to Geron in the second quarter of 2019; (ii) that IMbark and IMerge will continue; (iii) Geron’s plans to initiate the Phase 3 portion of IMerge in mid-2019; (iv) that Geron will outline a decision for myelofibrosis development by the end of the third quarter 2019; (v) that imetelstat for MDS would be prescribed before or in lieu of lenalidomide and/or hypomethylating agents; (vi) financial or operating projections or requirements of Geron; and (vii) other statements that are not historical facts, 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: (i) whether contingencies delay or prevent the start of the Phase 3 portion of IMerge by mid-year 2019; (ii) whether regulatory authorities permit the further development of imetelstat on a timely basis, or at all; (iii) whether Geron decides for any reason not to develop imetelstat for myelofibrosis; (iv) whether any circumstances arise that prevent a timely transition of the imetelstat program from Janssen; (v) whether Geron’s patents protect the commercial value of imetelstat; (vi) whether imetelstat’s benefit-risk profile for MDS is better than lenalidomide and/or hypomethylating agents; and (vii) whether Geron can obtain sufficient funding to support further development of imetelstat. 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 Geron's quarterly report on Form 10-Q for the quarter ending September 30, 2018. 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.

2 Geron Overview

Company • A late-stage clinical development biopharmaceutical company with 100% ownership of imetelstat, a Phase 3-ready asset • Sufficient cash ($185M as of 9/30/18) to move imetelstat forward into Phase 3 Imetelstat • A first-in-class telomerase inhibitor, focused on hematologic myeloid malignancies • Clinical evidence of potential disease-modifying activity in three myeloid malignancies: essential thrombocythemia (ET), myelofibrosis (MF) and myelodysplastic syndromes (MDS) • Granted Fast Track designation by FDA for treatment of lower risk MDS patients Current Clinical Trials • IMerge: Phase 2/3 trial in lower risk MDS • IMbark: Phase 2 trial in Intermediate-2 or High-risk MF • Oral presentations of updated data for both trials scheduled at American Society of Hematology (ASH) Annual Meeting Future Plans • Screening and enrollment for Phase 3 portion of IMerge planned to begin by mid-year 2019 • Exploring potential for late-stage development in MF, expect decision by end of third quarter 2019

3 Telomerase A novel molecular target in oncology

Telomerase enzyme Malignant Progenitor Cells • Comprised of an RNA template component Telomerase highly upregulated, in over (hTR) and a reverse transcriptase catalytic 90% of cancers, enabling continued and protein subunit (hTERT) uncontrolled proliferation • In 2009, three Geron collaborators won the Nobel Prize for Medicine for discovery of telomerase and its relationship with telomeres Normal Progenitor Cells Telomerase transiently upregulated to support controlled proliferation

Somatic Cells RNA template Telomerase inactive telomeric DNA (hTR) catalytic subunit (hTERT)

4 Imetelstat A first-in-class telomerase inhibitor

imetelstat • Target: malignant progenitor cell clonal proliferation NPS oligonucleotide lipid tail • Structure: 13-mer thio-phosphoramidate (NPS) oligonucleotide complementary to hTR, with covalently-bound lipid tail to increase cell permeability/tissue distribution Imetelstat binds • Long tissue residence time in bone marrow, to RNA template of telomerase spleen, liver • Potent competitive inhibitor of telomerase X • Clinical experience: more than 600 patients treated in Phase 1 and 2 trials telomere Prevents binding by and maintenance of telomeres

5 Imetelstat Key differentiating features Targeting telomerase to tackle the underlying disease Unique • Telomerase activity is high in patients with myeloproliferative neoplasms Mechanism • Inhibiting telomerase expression limits the proliferation of malignant progenitor cell clones of Action that drive the disease

Trial eligibility criteria emphasizes difficult-to-treat patients Challenging • IMerge – open to all MDS subtypes, minimum transfusion burden of 4.0 units/8 weeks, pre- Patient transfusion hemoglobin ≤ 9.0 g/dL • IMbark – must show objective evidence of disease progression during or after treatment with Populations a JAK inhibitor (JAKi) or never responded to JAKi treatment plus active symptoms of MF Tested

Activity within multiple outcome measures suggest clinical benefit • IMerge – ≥8-week red blood cell (RBC) transfusion independence (TI) achieved across MDS Broad subtypes (ring-sideroblast, RS +/-) and erythropoietin (EPO) levels, reductions in transfusion Clinical burden in all patients Activity • IMbark – range of reductions in Total Symptom Score, potential improvement in overall survival for 9.4 mg/kg arm, including patients with at least one high-risk mutation and triple negative mutation patients 6 Hematologic Myeloid Malignancies Clinical evidence of potential disease modifying activity

All arise from malignant progenitor cell clones in the bone marrow

telomerase

Baerlocher et al, NEJM 2015; 373:920-928

Steensma et al, 2018 ASH Abstract #463

Tefferi Pilot Study, unpublished

Tefferi et al, NEJM 2015; 373:908-919 7 Myelodysplastic Syndromes (MDS) Disease characteristics

• MDS is a diverse group of clonal hematologic malignancies • Comprised of numerous subtypes, including refractory anemia with ring-sideroblasts (RARS) and refractory cytopenia with multi-lineage dysplasia-RS (RCMD-RS) • RS+ MDS associated with lower risk of AML telomerase transformation and better survival than RS- patients • Median age at diagnosis is 70 • Up to 30% of patients progress to acute leukemia (AML) Lower Risk MDS • Median overall-survival is 3.5-5.7 years • Chronic anemia is the predominant clinical problem, many patients are dependent on RBC transfusions • Transfusion dependency is associated with iron overload, and shorter survival - 2 units of RBC monthly may reduce life expectancy by 50% and Sekeres, Natl Compr Canc Netw 2011; 9:57-63 Bejar & Steensma, Blood 2014; 124:2793-2803 increase risk of progression to AML Greenberg et al, Blood 1997; 89:2079-2088 Malcovati et al, JCO 2007; 25:3503-3510 www.cancer.org/cancer/myelodysplastic-syndromes 8 MDS Patient Population in the U.S. Addressing a large unmet need

60,000 MDS patients in the U.S. ~70% of MDS patients have 16,000 Lower Risk MDS Cases diagnosed annually in the U.S.

Cogle, Curr Hematol Malig Rep; 2015, 10272-10281 Greenberg et al, Blood 1997; 89:2079-2088 9 Treatment Landscape for Lower Risk MDS Chronic anemia remains an unmet need

Erythropoiesis Lenalidomide Stimulating Not approved in U.S. or Europe for Agents (ESAs) Patients non-del(5q) patients • ≥8-week RBC-TI: 27% • Improvement in refractory to anemia in ~50% of ESAs become patients dependent on • Median treatment duration: ~2 years red blood cell transfusions Hypomethylating Agents (HMAs) Approved in U.S. for all patients, including del(5q) and non-del(5q) Not approved in Europe • ≥8-week RBC-TI: ~17%

Fenaux and Adès, Blood 2013; 121:4280-4286 Santini et al, J Clin Oncol 2016; 34:2988-2996 Tobiasson et al, BCJ 2014; 4: e189 10 Treatment Landscape for Lower Risk MDS Opportunity to sequence imetelstat ahead of available therapies

Erythropoiesis Lenalidomide Stimulating Not approved in U.S. or Europe for Agents (ESAs) Patients non-del(5q) patients • ≥8-week RBC-TI: 27% • Improvement in refractory to anemia in ~50% of ESAs become patients dependent on • Median treatment red blood cell duration: ~2 years transfusions Hypomethylating Agents (HMAs) Approved in U.S. for all patients, Imetelstat including del(5q) and non-del(5q) ≥8-week RBC-TI: 37% Not approved in Europe potential to sequence ahead of • ≥8-week RBC-TI: ~17% lenalidomide and HMAs

ASH 2018 Abstract #463: Imetelstat Treatment Leads to Durable Transfusion Independence (TI) in RBC Transfusion-Dependent Fenaux and Adès, Blood 2013; 121:4280-4286 (TD), Non-Del(5q) Lower Risk MDS Relapsed/Refractory to Erythropoiesis-Stimulating Agent (ESA) Who Are Lenalidomide (LEN) Santini et al, J Clin Oncol 2016; 34:2988-2996 and HMA Naïve; Steensma D, et.al. Tobiasson et al, BCJ 2014; 4: e189 11 IMerge: 2-Part Phase 2/3 Trial ClinicalTrials.gov Part 1 – Phase 2 portion (NCT02598661)

IMerge Part 1: Phase 2 Portion Clinical Trial Conduct and Status • Initial enrollment: transfusion dependent patients single arm, 1° Efficacy: with IPSS Low or Intermediate-1 Risk MDS that is open label Red Blood Cell (RBC) Transfusion relapsed or refractory (R/R) to erythropoiesis (n = 57); Imetelstat Independence (TI) ≥8 weeks stimulating agent (ESA) treatment 7.5mg/kg 2° Efficacy: target RBC TI ≥24 weeks; • Results from initial enrollment presented at ASH in every 4 patient time to and duration of RBC TI; December 2017 and the European Hematology population weeks hematologic improvement (HI); Association (EHA) in June 2018 (n=38) reduction in RBC burden • Starting dose confirmed

• Transfusion dependent is defined as an RBC transfusion • Target patient population defined: no del(5q) requirement of ≥4 units over 8 weeks prior to trial entry chromosomal abnormality or non-del(5q), naïve to • ESA R/R following ≥8 weeks of weekly epoetin alfa 40,000 U or lenalidomide or HMA treatment darbepoetin alfa 150 mcg (or equivalent) or serum erythropoietin (sEPO) >500 mU/mL • Fast Track designation by FDA for treatment of lower • Supportive care permitted in both arms: RBC transfusions, myeloid risk MDS patients growth factors per investigator discretion as clinically needed and • More mature data for target patient population local guidelines (n=38) to be presented at ASH in December • Treatment and follow-up continuing as per protocol

12 Lower Risk MDS Trials Targeting different patient populations

IMerge MEDALIST Geron Company Acceleron/Celgene Imetelstat Drug name Luspatercept Telomerase inhibitor Mechanism of action TGF-b inhibitor Phase 2 (n=38) Phase of development Phase 3 (n=229) active (n=153), placebo (n=76) MDS subtype RS+ or RS- RS+ only Ring-sideroblasts (RS) Minimum transfusion burden for ≥4 units/8 weeks “Required RBC transfusions” enrollment 8 (4-14) Median baseline transfusion burden 5 (1-20) # units/8 weeks (range) 29% < 4 units

IMerge focused on high transfusion burden patients and open to all MDS subtypes

ASH 2018 Abstract #463: Imetelstat Treatment Leads to Durable Transfusion Independence (TI) in RBC Transfusion-Dependent (TD), Non-Del(5q) Lower Risk MDS Relapsed/Refractory to Erythropoiesis- Stimulating Agent (ESA) Who Are Lenalidomide (LEN) and HMA Naïve; Steensma D, et.al.

ASH 2018 Abstract #1: The Medalist Trial: Results of a Phase 3, Randomized, Double-Blind, Placebo-Controlled Study of Luspatercept to Treat Anemia in Patients with Very Low-, Low-, or Intermediate- Risk Myelodysplastic Syndromes (MDS) with Ring Sideroblasts (RS) Who Require Red Blood Cell (RBC) Transfusions 13 IMerge Part 1: Target Patient Population ClinicalTrials.gov Results from ASH abstract (NCT02598661)

IMerge Target Patient Population* (n=38) Safety 8.0 units/8 weeks; Baseline median RBC transfusion burden Safety profile consistent with previous imetelstat range 4-14 clinical trials in hematologic myeloid ≥8-week RBC-TI 37% (14/38) malignancies • ≥8-week RBC-TI observed across MDS subtypes Adverse events such as cytopenias, gastrointestinal or constitutional symptoms RARS/RCMD-RS (RS+) 33% and hepatic biochemistry abnormalities

Other Patients (RS-) 27% • No new safety signals reported • Myelosuppression is dose-limiting toxicity ≥8-week RBC-TI consistent across baseline EPO levels observed (managed through dose holds and EPO >500 mU/mL 33% modification rules)

EPO ≤500 mU/mL 32% • Most cytopenias resolved within 4 weeks

*Transfusion dependent patients with IPSS Low or Intermediate-1 Risk MDS, who are non-del(5q), R/R to ESAs and naïve to lenalidomide and HMA treatment

More mature data expected in oral presentation at ASH on December 2, 2018

Data from Part 1 for target patient population support moving forward with Part 2 Patient screening and enrollment planned to begin mid-year 2019*

Current Clinical Trial Design for IMerge Part 2: Phase 3 Portion

Imetelstat 1° Efficacy: Transfusion Dependent, (n = ~115) Red Blood Cell (RBC) Transfusion

Low or Intermediate-1 (2:1) Independence (TI) ≥8 weeks

7.5mg/kg every 4 weeks blind Risk MDS, Non-del(5q), - 2° Efficacy: R/R ESAs, Naïve to RBC TI ≥24 weeks; Lenalidomide and HMA time to and duration of RBC TI; (n = ~170) Double Placebo hematologic improvement (HI); Randomize Randomize (n = ~55) reduction in RBC burden

• Transfusion dependent is defined as an RBC transfusion requirement of ≥4 units over 8 weeks prior to clinical trial entry • ESA R/R following ≥8 weeks of weekly epoetin alfa 40,000 U or darbepoetin alfa 150 mcg (or equivalent) or serum erythropoietin (sEPO) >500 mU/mL • Supportive care permitted in both arms: RBC transfusions, myeloid growth factors per investigator discretion as clinically needed and local guidelines

*Timing dependent upon transfer of imetelstat investigational new drug (IND) sponsorship from Janssen to Geron. 15 Myelofibrosis (MF) Disease characteristics

• Malignant clonal proliferation and atypical megakaryocytic hyperplasia leads to bone marrow fibrosis and impaired hematopoiesis – Fibrosis thought to be induced by inflammatory cytokines produced by megakaryocytes originating from the malignant progenitor cell clone telomerase – Constitutional symptoms (e.g., fever, weight loss, night sweats, pruritus) present in approximately 35% of patients also thought to be due to cytokines produced by malignant megakaryocytes – Impaired bone marrow hematopoiesis shifts blood production to spleen and liver (palpable splenomegaly in approximately 80% of patients) • Serious and life-threatening illness − Leukemic transformation to AML (blast-phase MF) − Thrombohemorrhagic complications associated with dysfunctional hematopoiesis − Median survival: ~1-3 years for intermediate-2 or high-risk disease Tefferi, JCO 2005; 23:8520-8530 Tefferi, Mayo Clin Proc 2012; 87:25-33 Gangat et al, JCO 2011; 29:392-397 16 MF Patient Population in the U.S. Addressing an underserved market

13,000 ~70% MF patients in the U.S. of MF patients have Intermediate-2 or 3,000 High-risk MF Cases diagnosed annually in the U.S.

Mehta et al, Leuk Lymphoma 2014; 55:595-600 Gangat et al, JCO 2011; 29:392-397 17 Current Treatments for Int-2/High-Risk MF No approved drug for patients relapsed/refractory to ruxolitinib

Ruxolitinib

• Primarily for symptoms or splenomegaly Investigational • Oral JAK1/JAK2 inhibitor 75% Agents • Only approved product 5-year ruxolitinib (e.g., imetelstat) for MF in U.S./Europe discontinuation rate • Stay on drug as long as tolerated Primary reasons: • Conventional drugs • Suboptimal response viewed as ineffective, • Loss of therapeutic effect especially in advanced disease After discontinuation of ruxolitinib Median Overall Survival is ~14-16 months Harrison et al, ASH 2015; Gupta et al, ASCO 2016 Newberry et al, Blood 2017; 130:1125-1131 Kuykendall et al, Ann Hematol 2018; 97:435-441 Spiegel et al, Blood Advances 2017; 1:1729-1738

18 IMbark Phase 2 Trial ClincialTrials.gov Rigorously defined relapsed/refractory MF patients (NCT02426086)

Trial Population: • Patients with Intermediate-2 or High-risk MF • Relapsed or refractory (R/R) to JAKi treatment Key Goals: • Define appropriate dosing (9.4 or 4.7 mg/kg every 3 weeks) • Confirm safety and clinical benefit in this high unmet need population

Imetelstat Co-1° Efficacy: 9.4 mg/kg Spleen response rate and symptom response rate every 3 weeks 2° Efficacy: Intermediate-2 or High-risk CR, PR and CI, anemia response per 2013 IWG-MRT MF criteria, duration of responses, overall survival (OS) R/R to JAKi treatment Imetelstat Exploratory: 4.7 mg/kg

Randomize (1:1) Randomize Cytogenetic and molecular responses, leukemia free every 3 weeks survival

19 IMbark Results from ASH Abstract Eligibility criteria yields poor-prognosis MF patient population ClincialTrials.gov First trial requiring patients to meet rigorous definition of relapsed/refractory to JAKi (NCT02426086) • Objective evidence of disease progression during or after treatment with a JAKi through worsening splenomegaly or never responded to JAKi treatment through no reduction in spleen size after 12 weeks of JAKi therapy • Active symptoms of MF with minimum symptom score of 5 out of 10 Patient demographic highlights: 1) Considerable proportion of DIPSS high-risk MF • 41% (44/107) • These patients have a high risk for leukemic transformation 2) Sizeable triple negative patient population • 25% (26/105) • Triple negative means an absence of JAK2, MPL or CALR mutations • Triple negative patients have poor overall survival, an increased risk of leukemic transformation and do not respond well to existing therapies 3) Significant number of high molecular risk patients • 68% (71/105) • Presence of at least 1 mutation in high-molecular risk genes, ASXL1, EZH2, IDH1/2 and SRSF2 • These genes have been associated with inferior prognosis

4.7 mg/kg 9.4 mg/kg 4.7 mg/kg 9.4 mg/kg (n=48) (n59) (n=48) (n59) Spleen Response 0% 10% (6/59) Symptom Response 6% (3/48) 32% (19/59)

Spleen Response: proportion of patients who achieve a ≥35% reduction in spleen volume assessed by imaging at 24 weeks in comparison to baseline Symptom Response: proportion of patients who achieve a ≥50% reduction in Total Symptom Score at 24 weeks in comparison to baseline

4.7 mg/kg (n=48) 9.4 mg/kg (n59) Median follow-up: Median Overall Survival 20 mos not reached 22.6 mos (range: 0.2 – 27.4)

Median Overall Survival: length of time from trial enrollment where half of the assessable patients in a group are still alive

Additional Overall Survival Analyses: 1) Improvement in OS for the 9.4 mg/kg arm does not appear to be due to post-imetelstat intervention with either JAKi or allogeneic stem cell transplant • A sensitivity analysis censoring patients at the time of subsequent JAKi therapy or stem cell transplant resulted in a median OS that had still not been reached 2) Triple negative patients in the 9.4 mg/kg dosing arm showed promising overall survival despite this subpopulation being difficult to treat using current available therapy

Most Common Adverse Event on 4.7 mg/kg 9.4 mg/kg Treatment (all grades) (n=48) (n=59) Safety Thrombocytopenia 23% 49% Safety profile consistent with previous imetelstat Anemia 31% 44% clinical trials in hematologic myeloid malignancies Neutropenia NR 36% • Adverse events such as cytopenias, Diarrhea 38% NR gastrointestinal or constitutional symptoms and hepatic biochemistry abnormalities Nausea 31% 34% NR: not reported in abstract • No new safety signals reported • Myelosuppression is dose-limiting toxicity 4.7 mg/kg 9.4 mg/kg observed (managed through dose holds and Grade 3/4 (n=48) (n=59) modification rules) Thrombocytopenia 29% 42% • Most cytopenias resolved within 4 weeks Neutropenia 13% 34%

ASH 2018 Abstract #685: Imetelstat is Effective Treatment for Patients with Intermediate-2 or High-Risk Myelofibrosis Who Have Relapsed on or Are Refractory to Janus Kinase Inhibitor Therapy: Results of a Phase 2 Randomized Study of Two Dose Levels; Mascarhenas, J., et al. 23 IMbark Results ClincialTrials.gov Key conclusions (NCT02426086) Clinical activity demonstrated in 9.4 mg/kg dosing arm • No formal clinical trial conducted previously for patients R/R to JAKi • Potential improvement in survival observed • Median OS for previously treated JAKi patients reported to be 12 – 14 mos (Kuykendall Ann Hematol 2018; Newberry Blood 2017) Safety profile considered acceptable for this poor-prognosis population Data warrant further exploration in future studies Geron’s plan in MF • Discuss IMbark results with MF experts and regulatory authorities to explore potential for late-stage development in MF • Expect to outline a decision by end of third quarter of 2019 More mature data from extension phase of IMbark, including updated median overall survival for the 9.4 mg/kg arm, expected in oral presentation at ASH on December 3, 2018

Data Presentations Clinical Development Plans

ASH abstracts published online Discussions with MF experts and regulatory ✓ November 1, 2018 authorities to determine next steps Start of first quarter 2019 IMerge Phase 2 data presentation at ASH December 2, 2018 Imetelstat IND transfers from Janssen to Geron IMbark Phase 2 data presentation at ASH Second quarter 2019 December 3, 2018 Initiate screening and enrollment for Phase 3 Analyst and investor event portion of IMerge December 10, 2018 By mid-year 2019

Outline decision regarding potential late- stage development in MF End of third quarter 2019

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