Design, Objectives, and Status ofAsterias’ Current Spinal Cord InjuryClinical Trial Edward Wirth, III, M.D., Ph.D. Chief Medical Officer Investor DayMay 8, 2015  * 

 AST-OPC1: Phase 1 Safety Study in Complete Thoracic SCI  *  MRI  MRI  MRI  MRI  MRI  MRI  MRI  MRI  MRI  MRI  Primary Assessment: SafetySecondary Assessment: ISNCSCI examsExploratory AssessmentsUAB-IMRSCIMSCI Pain Basic Data SetBowel and Bladder Basic Data Set  Open Label TrialMulti-Center (7 sites)8-10 SubjectsSubacute, Neurologically Complete T3-T11 Lesions2x106 CellsTransplant 7-14 Days Post InjuryTemporary Immunosuppression  

 AST-OPC1: Subject Demographics  Demographic and Baseline Disease Characteristics – All Treated Subjects  Demographic and Baseline Disease Characteristics – All Treated Subjects  Demographic and Baseline Disease Characteristics – All Treated Subjects  Demographic and Baseline Disease Characteristics – All Treated Subjects  Demographic and Baseline Disease Characteristics – All Treated Subjects  Age(years)  Sex  Level of Injury  Cause of Injury    21  Male  T6  Motor vehicle accident    23  Male  T8  Restrained driver in rollover motor vehicle collision with ejection    32  Male  T6  Motorcross    31  Male  T7  Fell 30 feet down rock embankment    23  Female  T3  Car accident    Dr. David Apple  Dr. Gary SteinbergDr. Steve McKenna  Dr. Richard FesslerDr. David Chen  Enrolling Sites  * 

 Delivery of AST-OPC1 in Complete Thoracic SCI Was Feasible and Safe  *  All Subjects Received AST-OPC1 (2 x 106 cells) at 1-2 weeks of post-injuryInjections performed using a Syringe Positioning Device (SPD)No intraoperative complicationsNo SAEs Associated with Delivery of Cells9 Adverse Events Possibly Related to Injection Procedure All Grade 1 or 2: Post-Operative Pain, Transient Fever (1) or Urinary Tract Infection (1) 

 Immunosuppression Regimen Was Well-Tolerated   All Subjects Completed Tacrolimus Immunosuppression RegimenNo SAE’s Associated with Immunosuppression16 Grade 1 or 2 Adverse Events Possibly Associated with ImmunosuppressionNausea, Urinary Tract Infection, Low Magnesium Blood Levels  * 

 No Evidence of AST-OPC1 Directed Immune Responses One Year After Administration  Immune monitoring shows no evidence of antibodies or cellular immune responses to AST-OPC1 through 1 year in all subjects Some subjects complete mismatch with AST-OPC1: Closest match was 5 of 10 alleles  PRA Assay  ELISpot Assay  Day Post AST-OPC1 Transplant  Day Post AST-OPC1 Transplant  * 

  AST-OPC1 Was Well Tolerated   No SAE’s Associated with AST-OPC1No Evidence of adverse findings on MRI scans5 Adverse Events Possibly Associated with AST-OPC1Transient Low Grade Fever (1)Burning Sensation in Trunk and Lower Extremities (4 in one subject)  Subject  SAE  Timeframe  Related to AST-OPC1  1101  Pyelonephritis: Grade 2  Day 215  Not Related  1204  Urinary tract infection: Grade 3  Day 325  Not Related  1204  Autonomic Dysreflexia/Dyspnea: Grade 3  Year 2  Not Related  *  Three SAEs to date 

 No Major Sensory Neurological Changes Observed      Neurological Level  Neurological Level  Zone of Partial Preservation  Zone of Partial Preservation  Subject  Visit  Right Side Sensory  Left Side Sensory  Right Side Sensory  Left Side Sensory  1002  Baseline  T6  T6  T7  T7    Year 1  T6  T7  T7  T7    Year 2  T6  T6  T7  T7    Year 3  T6  T6  T7  T7  1003  Baseline  T8  T8  T9  T9    Year 1  T8  T8  T10*  T10*    Year 2  T8  T9  T10  T10  1101  Baseline   T6  T6  T8  T8    Year 1  T6  T6  T8  T8    Year 2  T5  T5  T7  T7  1203  Baseline  T7  T8  T8  T9    Year 1  T7  T8  T9  T10    Year 2  T8  T8  T9  T9  1204  Baseline   T3  T3  T4  T4    Year 1  T4  T4  T6  T5    Year 2  T4  T4  T6  T5  * Day 270  * 

 MRI Results: Evidence Consistent with Prevention of Lesion Cavity Formation  No adverse findings on primary MRI safety readsIn 4 of 5 subjects, graft sites are hyperintense on T2, but signal intensity is < CSFSuggests lesion cavity formation may have been prevented by formation of a tissue matrix  Image on right is axial T2 at 3 years post-grafting through center of lesion/graft site – Slice 22 on sagittal image above)  * 

 Summary of Findings from First in Man Study of AST-OPC1  AST-OPC1 is extremely well tolerated, with no SAEs to date deemed related to the cells, delivery method, or immunosuppressive regimen4 of 5 patients have completed 3 year follow up visit, one has completed 4 years of follow-up5th patient will complete 3 year follow up in early NovemberImmune response monitoring shows no evidence of rejection of AST-OPC1, even 10 months after removal of all immunosuppressionDespite significant HLA mismatches between AST-OPC1 and subjectsSuggests well tolerated low dose, transient immunosuppressive regimen likely sufficient to enable long term engraftment of cellsMRI results consistent with continued, stable engraftment in 4 of 5 subjects at 2-3 years post-transplantNo evidence of significant changes in neurological functionNo evidence for ascending loss of function from cells or deliveryEfficacy not anticipated in this study due to low dose (5-10x below predicted efficacious range) and suboptimal patient population (complete thoracic injuries)  * 

 AST-OPC1: Scientific Rationale for Evaluation in Cervical SCI Patients  Repair/regeneration of axons only required over a short distance to reinnervate motor neurons for arms & handsFor example, with an SCI at C6 (last intact motor level at C5), repair of axons to C7 could yield return of 2 motor levels  Cervical SCIRepair  Thoracic SCIRepair  * 

 AST-OPC1: Medical Rationale for Evaluation in Cervical SCI Patients  Few complete cervical SCI patients recover >= 2 motor levels with current standard of careRecovery of >= 2 motor levels leads to significant improvement in self-care abilitySelf-care ability could be a clinically meaningful endpoint for a pivotal trial and BLA approval  Analysis by SCOPE (Spinal Cord Outcomes Partnership Endeavor)Steeves et al., 2012. Top Spinal Cord Inj Rehabil 18:1-14  * 

 Design of Phase 1/2a Study of AST-OPC1 in Complete Cervical SCI  6m efficacy data  10M cell cohort (N=5)  20M cell cohort (N=5)  2M cell cohort (N=3)  Key Design ElementsAST-OPC1 Injection 14-30 days post-injury10 day stagger within cohortsDMC review prior to dose escalation  Efficacy TargetRecovery of >= 2 motor levels at 6 months or 12 months  * 

 AST-OPC1 Phase 1/2a Study Schema  *  Acute completecervical SCI  Protocol AST-OPC1-01  Protocol AST-OPC1-02  Day 0  Day 7  Day 30  Day 60  Day 90  Day 180  1 Year  5 Years  15 Years  In personvisits  Phone f/u  DiscontinueImmunosuppression  Days 46-60ImmunosuppressionTaper  AST-OPC1Injection14-30 DaysPost-SCI  Day -1  Screening  Baseline  Day -3  Day -11  MRI  MRI  MRI  MRI  MRI  Primary Assessment: SafetySecondary Assessment: ISNCSCI examsExploratory Assessments: SCIM, GRASSP   Open Label TrialMulti-Center (8 sites)Complete cervical SCI (C5-C7)Temporary Immunosuppression  

 Operational Update  First two clinical sites are open for enrollment (Shepherd Center, Atlanta; Rush University, Chicago)Third clinical site expected to open in May (Stanford/Santa Clara Valley Medical Center)Patient recruitment efforts initiatedStudy website landing page to go live in MayBranding and messaging for health care providers developedOutreach to referral centers for open sites has begun  * 

 AST-OPC1 Phase 1/2a Trial: Design and Milestones  *  Cohort 1:3 subjects2 million cells  Cohort 2:5 subjects10 million cells  Cohort 3:5 subjects20 million cells  Q1’15: Study initiates  Q3’15: Dose escalation  Q1’16: Dose escalation  1H’16: 6 mo efficacy, cohort 2