Clinical-Stage Immunotherapy and Neurology Company Asterias BiotherapeuticsNYSE Market: ASTDecember 2018 Filed by Asterias Biotherapeutics, Inc.Pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of theSecurities Exchange Act of 1934 Subject Corporation: Asterias Biotherapeutics, Inc. Commission File No.: 001-36646

2 Statements pertaining to future financial and/or operating and/or clinical research results, future growth in research, technology, clinical development, and potential opportunities for Asterias, along with other statements about the future expectations, beliefs, goals, plans, or prospects expressed by management constitute forward-looking statements. Any statements that are not historical fact (including, but not limited to statements that contain words such as "will," "believes," "plans," "anticipates," "expects," "estimates") should also be considered to be forward-looking statements. Forward-looking statements involve risks and uncertainties, including, without limitation, risks inherent in the development and/or commercialization of potential products, uncertainty in the results of clinical trials or regulatory approvals, need and ability to obtain future capital, and maintenance of intellectual property rights. Actual results may differ materially from the results anticipated in these forward-looking statements and as such should be evaluated together with the many uncertainties that affect the businesses of Asterias, particularly those mentioned in the cautionary statements found in Asterias' filings with the Securities and Exchange Commission (the “SEC”). Asterias disclaims any intent or obligation to update these forward-looking statements.Certain statements in this communication, including statements relating to the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement and the combined company’s future financial condition performance and operating results, strategy and plans are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 giving Asterias’ expectations or predictions of future financial or business performance or conditions. These forward-looking statements are subject to numerous assumptions, risks and uncertainties which change over time. Forward- looking statements speak only as of the date they are made and we assume no duty to update forward-looking statements. In addition to factors previously disclosed in Asterias’ reports filed with the SEC and those identified elsewhere in this communication, the following factors, among others, could cause actual results to differ materially from forward-looking statements and historical performance: the ability to obtain regulatory approvals and meet other closing conditions to the Merger, including requisite approval by Asterias’ stockholders and shareholders, respectively, on a timely basis or at all; delay in closing the Merger; the ultimate outcome and results of integrating the operations of BioTime and Asterias and the ultimate ability to realize synergies and other benefits; business disruption following the Merger; the availability and access, in general, of funds to fund operations and necessary capital expenditures. More information on potential factors that could affect our results is included from time to time in the SEC filings and reports of Asterias, including the risks identified under the sections captioned “Risk Factors” in Asterias’ annual report on Form 10-K filed with the SEC on March 15, 2018, and Asterias’ quarterly report on Form 10-Q for the quarter ended September 30, 2018, filed with the SEC on November 9, 2018. Forward-Looking Statements

3 On November 8, 2018, Asterias announced it had entered into an Agreement and Plan of Merger with BioTime, Inc. (NYSE MKT: BTX)BioTime previously owned approximately 39% of AsteriasStock merger with fixed exchange ratioEach AST share to convert into 0.71 shares of BTXCombined company to be run by BTX CEO Brian CulleyAST CEO Michael Mulroy to remain on BTX Board; AST Board Chair Don Bailey to join BTX BoardTransaction expected to close in Q1 of 2019 Announced Transaction with BioTime, Inc.

4 Asterias’ neurology platform is in the clinic with a Phase 1/2a clinical trial evaluating OPC1 in the treatment of severe cervical spinal cord injury (SCI)Significant pre-clinical data supporting clinical developmentClinical data showing positive safety profile, durable cell engraftment at the injury site, and promising motor recovery dataFDA discussions on next clinical study underwayOPC1 cells have mechanisms of action that can potentially help to treat other neurodegenerative diseases such as MS and White Matter StrokeAsterias’ immunotherapy platform is also in the clinic with a Phase 1 clinical trial evaluating VAC2 in patients with advanced and resected disease in non- small cell lung cancerVAC2 program uses dendritic cells to stimulate an immune response to telomerase, a universal cancer antigenEnrollment initiated in 2018; immunogenicity and activity data readouts anticipated in 2019 and 2020VAC2 is an allogeneic platform that can be used to deliver any antigen(s), including neo-antigen approachesNon-Dilutive Funding Partners: Cancer Research UK is funding and running VAC2 Phase 1 trialCalifornia Institute of Regenerative Medicine provided a $14.3 million grant to support OPC1 Phase 1/2a study and has the potential to partially fund the next study for OPC1 Asterias Background Information

5 PROGRAM Partners/Funding PRECLIN PHASE 1 PHASE 2 PHASE 3Programs with Ongoing Clinical Studies AST-OPC1Spinal Cord Injury (subacute) AST-VAC2Lung Cancer Allogeneic Other Clinical Programs AST-VAC1Leukemia (AML) Autologous Phase 1/2a study enrolled; final data readout in Q1 2019 Positive phase 2 data End of Phase 2 meeting completed Phase 1 underway;data in 2019 and 2020 Clinical Programs – Development Pipeline

Spinal Cord Injury Program

AST-OPC1 is a cellular therapy utilizing oligodendrocyte progenitor cells (OPCs)OPCs are found in the human body and are precursors to oligodendrocyte cells which, among other things, provide electrical insulation for nerve axons in the form of a myelin sheathAST-OPC1 administers OPCs into the body to supplement the body’s own internal supply of OPCs with a non-patient specific supply of cells AST-OPC1 is derived from a well- established, pluripotent embryonic stem cell line originally isolated in the 1990s AST-OPC1: Introduction AST-OPC1 Injection Procedure 7

AST-OPC1 Potential Mechanisms of Action Secretes neurotrophic factors Promote increased neurite outgrowth Myelination of axons Rag2-/- γc-/- /shi mouse + AST-OPC1 Control Media AST-OPC1 CM shiverer mouse shi mouse + AST-OPC1 TubIII Prevents Cavitation Control AST-OPC1 8

Significant unmet medical need for patients with severe SCIThe therapeutic goal for AST-OPC1 is to help restore arm, hand and finger function in SCI patients thereby increasing their independence and quality of lifeSignificant lifetime direct healthcare costs; can reach $5 million for a patientVery high unemployment rate; 63% of cervical injury patients are unemployed 8 years post-injuryMotor level improvements can translate into clinically significant improvements in ability to self-care and significant reductions in cost of care AST-OPC1 in Spinal Cord Injury (SCI) (1) Estimates by indication calculated based on 2014 NSCIC survey data, adjusted to exclude penetrating and secondary medical injuries 9 Target patient estimates(1)>4,000 under first label C4-C7 ASIA A/B/C

Potential to Have Clinically Meaningful Benefit Capability C1-C3 C4 C5 C6 C7-C8 Bowel Bladder Bed Mobility Transfers Pressure Relief Eating Dressing Grooming Bathing Wheelchair Car Transport Daily Home Care 24 hr Attendant 18-24 hr Attendant 6-12 hr Assistance 4 hr Housework 1 hr Housework Steeves et al., Top Spinal Cord Inj Rehabil 2012; 18(1): 1-14 Total Assist Partial Assist Independent 10

Survives in the Spinal CordGreatest Activity in Subacute InjuryImproves Locomotor ActivityReduces Parenchymal CavitationMigrates Up 5cm in Spinal CordNo Distribution Outside CNSDoes Not Increase MortalityDoes Not Induce Systemic ToxicityDoes Not Produce TeratomasProduces Low Frequency (1-2%) Small Ectopic Tissue at Injury SiteNot Highly Susceptible to Direct Immune Responses 28 Animal Studies>3000 Rodents and Pigs Pre-Clinical and Clinical Evidence Supporting OPC1 in SCI Pre-Clinical Clinical 5 subjects with thoracic injuries administered safety dose of 2M cellsLong-term follow up has shown no evidence of adverse changes in any of the subjects treated with AST-OPC1 Phase 1 Thoracic Study 25 subjects with cervical injuries administered up to 20M cellsPositive safety profileEvidence of durable cell engraftmentPromising motor recoveryResults defining population for next study 11 Phase 1/2a Study

To date, there have been no serious adverse events (SAEs) related to the OPC1 cellsThere have been no serious, unexpected, adverse events related to OPC1, the injection procedure, or the drug used for immunosuppressionSafety profile includes long- term follow up of Phase 1 safety study subjects through up to seven years post-injection of AST-OPC1 - no evidence of adverse changes in any of the OPC1 Clinical Data from Phase 1/2a study MRI results for over 96% (24/25) of subjects from Phase 1/2a study provide supportive evidence that OPC1 cells have durably engrafted at the injury siteSubject 365 Day T2 MRI At twelve months, 94% (17/18) of subjects administered 10M or 20M OPC1 cells in Phase 1/2a study recovered at least one motor level on at least one side and 33% of these subjects recovered at least two or more motor levels on at least one sideAsterias intends to report 12 month results for the entire Phase 1/2a study in the first quarter of 2019 subjects 12 Safety Cell Engraftment Motor Recovery

FDA has granted the Regenerative Medicine Advanced Therapy (RMAT) designation for AST-OPC1The RMAT designation is granted to regenerative medicine therapies for which “preliminary clinical evidence indicates that the drug has the potential to address unmet medical needs” for a “serious or life-threatening condition”1Asterias is using the RMAT Designation to initiate formal discussions with FDA on the next study for AST-OPC1 RMAT Designation 1 21st Century Cures Act, Section 3033 13

Immunotherapy Platform

15 Early Successes in Cancer Immunotherapy Have Improved Cancer Treatment in Recent Years But More is Needed VAC2 PlatformStimulate T cell response through natural antigen presentation mechanismLess potent initial immunity; best suited for MRD and combination approachesApplicable to wide range of antigensPotential for cross presentationHigh tolerability Immune Checkpoint InhibitorsHighly effective when existing T cell response is suppressed by tumorCannot mount a de novo T cell response in an “immune cold” tumor Car-T CellsStimulate T cell response through direct engineeringHigh remission rates, but frequent relapsesTargets single antigenLimited available targetsHigh toxicity/low tolerability Combining Several Approaches May be Necessary to Develop a More Potent Efficacious Therapy

Our VAC2 program uses dendritic cells to stimulate an immune response to telomerase, a universal cancer antigenThe LAMP signal sequence is also used to optimize immune response through stimulation of both CD8+ cytotoxic and CD4+ helper T cell responsesAST-VAC2 allogeneic dendritic cells are manufactured from embryonic stem cellsOptimal settings for use of DC immunotherapy approach include:Minimal residual disease setting /preventing relapse (monotherapy)Combination therapy with immune checkpoint inhibition Dendritic Cells:Potent Antigen Presenting Cells 16 Proprietary and Confidential Information Telomerase: “Universal” Tumor Antigen (Present in >85% of all cancers) AST-VAC2 Immunotherapy Program: Introduction

20-40% 10-20% 58% All patients in CR (N=19) 57% >60 years old (N=7) Relapse free survival at 52 months% of patients AST-VAC1Historical 17 Proprietary and Confidential Information VAC1 Phase 2 Study Results in AML VAC1 Phase 2 trial highlights Multicenter, open-label studyIncluded only intermediate and high risk patients, evaluated by cytogeneticsAll patients had already achieved CRResults exceeded expected long term RFS rates in all patientsParticularly dramatic was replication of the all patient results in the higher risk>60 population Source: Asterias results presented at ASCO May 2015;Historical controls based on Mayer NEJM 1994; Rollig, J Clin Onc 2011

VAC2 Builds on VAC1 POC With An Allogeneic Dendritic Cell Product Product to be supplied from a single master cell bank, allowing scalability/consistencyThousands of patient treatments can be manufactured in a single batchCryopreserved product available ‘off-the-shelf’ on demand Culture Electroporate RNA Culture Leukapheresis Cryopreserve Thaw Inject Thaw 18 Proprietary and Confidential Information Inject VAC1 Process: VAC2 Process:

VAC2 Phase 1 Study Underway Patient Population Patients with NSCLC 12 PatientsDose 1x107 AST-VAC26 Doses id. HLA A2 Typing 2 Year Follow- up for Responses/ Relapse Control ARM HLA-A2-Patients with Advanced Disease 12 PatientsNo Vaccine 12 PatientsDose 1x107 AST-VAC26 Doses id. Control ARM HLA-A2- Patients withResected Disease 12 PatientsNo Vaccine ARM ATreatment ARM HLA-A2+Patients with Advanced Disease ARM B ARM CTreatment ARM HLA-A2+ Patients withResected Disease ARM D Safety Review LTFU Establish safety of AST-VAC2 in resected and advanced cancerAssess the generation of anti-hTERT and anti-VAC2 Immune Responses Periodically Over 1 YearInvestigate Initial Measures of Clinical Activity as Progression Over 2 Years Trial Objectives 19 Proprietary and Confidential Information Study will provide POC data for AST-VAC2 to Enable Broad Development

Cancer Research UK Partnership to Execute VAC2 Clinical Trial in NSCLC to Establish Safety of Allogeneic Approach and Enable Other VAC2 Studies Asterias Performed Development and Transfer of Clinical AST-VAC2 Manufacturing ProcessCRUK Responsibilities:Execute cGMP Manufacture of AST-VAC2 for Clinical TrialPrepare and File of Regulatory DossierExecute 24 patient Phase 1/2a trial in Patients with Advanced and Resected Non- small Cell Lung Cancer (NSCLC) Tech transfer completedcGMP DP production campaigns ongoingMHRA and REC authorization receivedClinical sites selectedcGMP Drug Product releaseClinical contracts and site startupTrial open, FPI and FPFDData readouts anticipated in 2019 and 2020 20 Proprietary and Confidential Information

VAC2 Platform has Broad Potential For Application Beyond Current Areas of Focus Monotherapy in MRD Setting With High Risk of Relapse Approach: Rationale: Stimulate T cell response to ‘seek and destroy’ residual cancer stem cells after debulking chemotherapy, surgery, radiotherapyPromising results from AML trial of AST-VAC1 Combination Therapy Stimulate endogenous T cell response to enable ICIs to work in ‘immune cold’ tumorsPromising results in literature from preclinical studies of DC + ICI combinations New & Additional Antigens 21 Proprietary and Confidential Information Autologous and allogeneic DC platforms can be used to deliver any antigen(s), including neoantigen approaches

22 Potential Future Milestones 2019 2020 2021 2022 2023 OPC1 12 month Top-Line Data Updatefrom Phase 1/2a studyFDA Clearance on next study designCIRM Grant Award for next study Publication on Phase 1/2a study FPI for Phase 2B RCTPhase 2B Enrollment Updates Phase 2B EnrollmentUpdates Enrollmentcompleted for Phase 2B RCT 6 and 12 month datareadouts from Phase 2B RCT VAC2 QP release of final batch of DPAdvanced Cohort last patient last visitSafety review of all data from patients in Advanced Cohort ahead of moving into recruitment of Resected CohortResected Cohort last patient last visitInitial Safety and Immunogenicity Data Updates 1 year clinical activityreadouts for Advanced Disease Cohort1 year clinical activity readouts for Resected Disease CohortAll safety and immunogenicity Data generated 2 year clinical activityreadouts for Advanced and Resected Disease Cohorts CSR and publicationon P1 NSCLC Trial