Zilucoplan in*Generalized*Myasthenia*GravisTop$line)Results)of)a)Phase)2)Study

December'10,'2018

2

Topics

Introduction

Myasthenia1Gravis1Disease1Overview

Phase121Results

Closing1Remarks

Q&A

Forward'Looking-Statements

This presentation contains "forward1looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including,

but not limited to, statements regarding the safety, efficacy, regulatory and clinical progress and therapeutic potential of our product

candidates, including zilucoplan SC, expectations surrounding plans to engage with regulatory agencies and timing thereof, plans and timing for

the presentation of clinical data, expectations surrounding the initiation of a Phase 3 clinical program evaluating zilucoplan SC for the treatment

of gMG and timing thereof, expectations surrounding the nomination of a new neurology indication for zilucoplan SC and timing thereof, our

market opportunities, the anticipated pricing of our product candidates, if approved, including zilucoplan SC, and management’s estimates

about the potential size and characteristics for the patient populations that our product candidates are targeting. All such forward1looking

statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could

cause actual results to differ materially and adversely from those set forth in or implied by such forward1looking statements. These risks and

uncertainties include the risks that Ra Pharma’s product candidates, including zilucoplan SC, will not successfully be developed or

commercialized; as well as the other factors discussed in the “Risk Factors” section in Ra Pharma’s most recently filed Annual Report on Form

101K, as well as other risks detailed in Ra Pharma’s subsequent filings with the Securities and Exchange Commission. There can be no assurance

that the actual results or developments anticipated by Ra Pharma will be realized or, even if substantially realized, that they will have the

expected consequences to, or effects on, Ra Pharma. Except as noted, information in this presentation is as of December 10, 2018, and Ra

Pharma undertakes no duty to update this information unless required by law.

3

4

Topics

Introduction

Myasthenia1Gravis1Disease1Overview

Phase121Results

Closing1Remarks

Q&A

5

Generalized*Myasthenia*Gravis*(gMG)*Is*a**Rare,*Debilitating,*C5;Mediated*Disease1

References:*1.*Howard*JF.*Lancet*Neurol.*2017;16(12):976A986.**2.*Gilhus*N,*N*Engl*J*Med*2016;375:2570A812015* 3. ContiAFine*BM.*J*Clin*Invest.*2006;*116(11):2843A2855.*4.*Wang*et*al.*BMC*Neurology.*2017;17:77A83.**5.*Renton*AE,*et*al.*JAMA*Neurol.*2015*Apr;72(4):396A404.**6.*Heatwole*C,*et*al.*J*Clin*Neuromuscul*Dis.*2011;*13(2):*85–94.*7.*MG*Cost*Calculator,*Data*on*File.**8.*Soliris®*[package*insert].*Alexion*Pharmaceuticals*Inc;*revised*10/2017.**9. Prime*Therapeutics.*AMCP*2018,*April*23A26,*Boston.

150;250/Million,*~60,000*(US),*~100,000*(EU),*~24,000*(JP)2

Autoantibodies*block*signals*from*nerves*to*muscles*and*complement*activation*destroys*the*neuromuscular*junction3

Acetylcholine*receptor*antibody*positive2

Serious*and*progressive! Significantly*impacts*quality*of*life1,2

!~80%*progress*to*generalized*muscle*weakness4

! ~20%*experience*crisis5

Sporadic,*expensive,*and*often*non;specific!Cholinesterase*inhibitors,*corticosteroids,*ISTs,*thymectomy! IVIG,*PLEX*total*maintenance*costs*~$150,0006,7*per*year!Eculizumab*(Soliris®;*Alexion),*biAweekly*IV*therapy*approved*in*20178; ~$700,0009

Autoantibodies*and*complement;mediated*destruction*of*the*neuromuscular*junction*cause*pathology*in*gMG1,2

Signal*blocked

Signal*proceeds

Myasthenia*Gravis

NormalAcetylcholine*(ACh)

Acetylcholinereceptor*(AChR)

Muscle*cell

Autoantibody*that*binds*to*AChR

ComplementAmediated*MAC*assembly

Muscle*contracts

Destruction*of*membrane

FREQUENCY

CAUSE

DIAGNOSIS

TREATMENT

CONSEQUENCES

Activated)by)non.self)cells Activated)by)antibody.antigen)complexes Activated)by)pathogen)surfaces

C5a

C3 C1q$$– C1r$$– C1s

C7,)C8,)C9

C5b6

Membrane)attack)complex)(MAC)

Binds&C5,&blocks&cleavageEculizumab$(IV)$

Zilucoplan$SCBinds&C5,&blocks&cleavage;Blocks&MAC&assembly

Proinflammatory&cytokine

Lectin$PathwayClassical$PathwayAlternative$Pathway

C5

C5b

C6

Factor D,)Factor)B

6

Zilucoplan:$A$Subcutaneously$SelfEadministered,$Macrocyclic$Peptide$Inhibitor$of$Complement$C5

aHUS/LN: Phase)1b positive

1

FactortargetedbyRaPharmaproductcandidates

Activatedbynon-selfcells Activatedbyantibody-antigencomplexes Activatedbypathogensurfaces

C5a

C3 C1q – C1r – C1s

C7,C8,C9

C5b6

MAC

BindsC5

FactorD,FactorB

eculizumab RA101495

Proinflammatorycytokine

BindsC5&C5b

LectinPathwayClassicalPathwayAlternativePathway

PNH:ruptureofRBC

gMG:destructionofneuromuscularjunction

LN:inflammationofkidneyglomerulus

C5

C2,C3,C4

C5b

C6

1

FactortargetedbyRaPharmaproductcandidates

Activatedbynon-selfcells Activatedbyantibody-antigencomplexes Activatedbypathogensurfaces

C5a

C3 C1q – C1r – C1s

C7,C8,C9

C5b6

MAC

BindsC5

FactorD,FactorB

eculizumab RA101495

Proinflammatorycytokine

BindsC5&C5b

LectinPathwayClassicalPathwayAlternativePathway

PNH:ruptureofRBC

gMG:destructionofneuromuscularjunction

LN:inflammationofkidneyglomerulus

C5

C2,C3,C4

C5b

C6

PNH: Phase 2 positive

gMG:$Phase)2)positive)

Neuropathies and$Myopathies: TBA

Multiple$Indications

15)amino.acid)cyclic)peptide)inhibitor)of)C5

Multiple(validated(indications,(pipeline1in1a1product(potential

PNH)– paroxysmal)nocturnal)hemoglobinuria;)gMG)– generalized)myasthenia)gravis;)aHUS)– atypical)hemolytic)uremic)syndrome;)LN)– lupus)nephritis

✅

✅

✅

7

Topics

Introduction

Myasthenia1Gravis1Disease1Overview

Phase121Results

Closing1Remarks

Q&A

8

Phase&2&Study&Targets&Broad&gMG&Patient&Population

Screening 1:1:1&Randomization 0.1&mg/kg&SC&+&Standard&of&Care LongFterm&Extension&(Active&Drug)

0.3&mg/kg&SC&+&Standard&of&Care

Placebo&+&Standard&of&Care

Main&Study&Period&(12&Weeks) Long&Term&Extension

Endpoints:

! Primary:&Change&in&QMG&score&from&baseline&to&week&12

! Key&Secondary: Change&in&MGHADL&score&from&baseline&to&week&12

! PreHspecified&significance&testing&at&1Hsided&alpha&of&0.1

Broad&Patient&Population:

! Generalized&MG&(Myasthenia&Gravis&Foundation&of&America&class&IIHIVa)

! AChRHantibody&positive

! Quantitative&Myasthenia&Gravis&(QMG)&score&of&≥&12

! Stable&doses&of&corticosteroids&and/or&immunosuppressants

! No&requirement&to&be&“refractory”&or&have&failed&multiple&prior&therapies

Randomized,&doubleHblind,&placeboHcontrolled,&multiHcenter&study&followed&by&an&openHlabel&longHterm&extension&(LTE)

Enrollment: 44&Patients&(vs.&target&of&36)

9

Baseline(Characteristics(Confirm(Breadth(of(gMG(Study(PopulationVariable Placebo((n=15) Zilucoplan 0.1(mg/kg((n=15) Zilucoplan 0.3(mg/kg((n=14)

Age, mean years,(± SD) 48,(15.7) 46,(15.7) 55,(15.5)

Male,,n(%), 4,(27%) 7,(47%) 10,(71%)

Race,,n(%)• White• Asian• Black or,African,American

12,(80%)1,(7%)2,(13%)

13,(87%)0

2,(13%)

11,(79%)1,(7%)2,(14%)

MGFA,Class,at,Screening• II• III• IVa

7,(47%)8,(53%)

0

5,(33%)10,(67%)

0

5,(36%)5,(36%)4,(29%)

Duration,of,Disease, mean,years,(min,,max) 8.0,(0.1,,20.9) 8.7,(1.6,,24.1) 8.3,(0.5,,26.0)

Baseline,QMG,Score, mean (± SD) 18.7,(4.0) 18.7,(4.0) 19.1,(5.1)

Baseline,MGPADL,Score, mean (± SD) 8.8,(3.6) 6.9,(3.3) 7.6,(2.6)

Baseline,MG,Composite,Score, mean (± SD) 18.7,(5.7) 14.5,(6.3) 14.6,(6.3)

Baseline,MGQoL15r,Score, mean (± SD) 15.9,(7.4) 19.1,(5.0) 16.5,(7.3)

Prior,MG,Therapies (Standard,of,Care)• Pyridostigmine,,n(%)• Corticosteroids,,n(%)• Immunosuppressants,,n(%)

14,(93%)13,(87%)12,(80%)

15,(100%)13,(87%)12,(80%)

14,(100%)14,(100%)9,(64%)

Prior,IVIG,,n(%) 9,(60%) 8,(53%) 10,(71%)

Prior,Plasma,Exchange,,n(%) 7,,(47%) 9,(60%) 7,(50%)

Prior,Thymectomy,,n(%) 5,(33%) 8,(53%) 7,(50%)

Prior,MG,Crisis,Requiring,Intubation,,n(%) 3,(20%) 4,(27%) 2,(14%)

NonIRefractoryPatients(Included9%(no(prior(steroids25%(no(prior(ISTs39%(no(prior(IVIG48%(no(prior(PLEX(

High(Unmet(Medical(Need

10

Primary'and'Key'Secondary'Endpoints'Met'with'0.3'mg/kg'Zilucoplan Dose:'Rapid,'Clinically'Meaningful,'and'Statistically'Significant'Reductions'in'QMG'and'MGGADL

Change'from'Baseline'in'QMG'

Pre&specified-significance-testing-at-1&sided-alpha-of-0.1-with-LOCF-ANCOVA-p-values-shown;-error-bars-denote-standard-errors-of least-squares-mean;-mITT

p=0.05p=0.04

G6.0

G3.2

G1.1

G3.4

!8

!6

!4

!2

0

S tu d y ,W e e k

Change,from,Baseline,(SEM)

P la c e b o0 .3 ,m g /k g ,Z ilu co p la n

0 1 2 4 8 12

!4

!2

0

S tu d y *W e e k

Change*from*Baseline*(SEM)

P la c e b o0 .3 *m g /k g *Z ilu co p la n

0 1 2 4 8 12

!8

!6

!4

!2

0

S tu d y ,W e e k

Change,from,Baseline,(SEM)

P la c e b o0 .3 ,m g /k g ,Z ilu co p la n

0 1 2 4 8 12

Change'from'Baseline'in'MGGADL

11

Primary'and'Key'Secondary'Endpoints'Also'Met'with'0.1'mg/kg'Zilucoplan Dose

Pre%specified,significance,testing,at,1%sided,alpha,of,0.1,with,LOCF,ANCOVA,p,values,shown;,error,bars,denote,standard,errors,of least,squares,mean;,mITT

A5.5 A3.3

!8

!6

!4

!2

0

S tu d y ,W e e k

Change,from,Baseline,(SEM)

P la c e b o

0 .1 ,m g /k g ,Z ilu co p la n

0 1 2 4 8 12

!4

!2

0

S tu d y *W e e k

Change*from*Baseline*(SEM)

P la c e b o

0 .1 *m g /k g *Z ilu co p la n

0 1 2 4 8 12

!8

!6

!4

!2

0

S tu d y ,W e e k

Change,from,Baseline,(SEM)

P la c e b o

0 .1 ,m g /k g ,Z ilu co p la n

0 1 2 4 8 12

A3.2

A1.1

p=0.09p=0.05

Change'from'Baseline'in'QMG' Change'from'Baseline'in'MGAADL

12

Pre$specified+Pooled+Analysis+of+Approval+Endpoint+(MG$ADL)+Satisfies+2$Sided+p<0.05+

LOCF'ANCOVA'2+sided'p'value'shown;'error'bars'denote'standard'errors'of'least'squares'mean;'mITT

*'Placebo+corrected'change'in'MG+ADL'at'26'weeks'in'REGAIN'study:'+1.9'LOCF'ANCOVA'p=0.039;'ref.'Howard'et'al'AANEM'2016

Zilucoplan in+Phase+2+met+approvable+endpoint+(MG$ADL)+at+12+weeks+with+similar+magnitude+and+statistical+

significance+as+eculizumab+in+Phase+3+REGAIN+study+at+26+weeks*

Change+from+Baseline+in+MG$ADL

$3.3

$1.1

p=0.047

!4

!2

0

S tu d y *W e e k

Change*from*Baseline*(SEM)

P la c e b o

P oo le d *A c tive

0 1 2 4 8 12

!4

!2

0

S tu d y *W e e k

Change*from*Baseline*(SEM)

P la c e b o

Z ilu co p lan *P oo led

0 1 2 4 8 12

Responder)Analysis:)Robust)and)Meaningful)Improvements)over)Placebo

QMG MG=ADL

Zilucoplan arm)favored)overall)and)in)patients)exhibiting)largest)point)

improvements)

13

14

Patients(Can(Achieve(Minimal(Symptom(Expression(by(Week(12

*Vissing)J,)Jacob)S,)Fujita)K,)et)al.)Minimal)Symptom)Expression)with)Eculizumab)in)Myasthenia)Gravis.))AANEM)2018

0 .1 $m g /kg $Zi lu co p la nW e e k $12

1200 $m gEcu l iz um a bW e e k $26

0 .3 $m g /kg $Zi lu co p la nW e e k $12

0

5

1 0

1 5

2 0

2 5

P la c e b o <C o r r e c t e d $R a t e s

Percent$of$$Patients$(%)

23%(of(patients((placeboAcorrected)(achieved(MSE(in(12(weeks(in(0.3(mg/kg(zilucoplan arm

Minimal(symptom(expression((MSE)(=((Achieving(MGAADL(score(of(0(or(1

15

Safety'and'Tolerability'Profile'Supports'Continued'Development

Placebo(n=15)

Zilucoplan 0.1'mg/kg'(n=15)

Zilucoplan 0.3'mg/kg'(n=14)

Patients'requiring rescue'with'IVIG'or'PLEX 3'(20%) 1'(7%) 0'(0%)Patients*with*adverse*events*(AEs) 12 15 12

Patients*with*related*AEs 3 8 3

Patients*with*serious*AEs 3 0 5

Patients*with*related*serious*AEs 0 0 0

Patients*with*most*common related*AEs:

Nausea 0 2 2

Injection*site*bruising 1 2 0

Injection*site*scab 0 3 0

Contusion 0 1 1

Headache 1 4 2

Patients*with*injection*site*reactions 3 4 3

• No*meningococcal*infections

• Profile*consistent*with*Ph1*and*Ph2*PNH*studies

MedDRA*Version*20.0*Adverse*Event*Preferred*Terms;*injection*site*reactions*defined*as*pain,*tenderness,*erythema,*or*induration

• All*44*subjects*completed*12Qweek*study;*No*early*withdrawals

• 43/44*subjects*(98%)*entered*longQterm*extension

No'patients'required'rescue'in'0.3'mg/kg'zilucoplan arm

16

! Positive*Phase*2*study*in*broad*gMG*population*(not*restricted*to*“refractory”)

! Primary*and*key*secondary*endpoints*met*with*clinically*meaningful*and*statistically*

significant*reductions*in*QMG*and*MGCADL*in*both*0.3*mg/kg*and*0.1*mg/kg*dose*

groups

! Magnitude*and*speed*of*effect,*no*rescue*therapy*required,*and*higher*rate*of*

minimal*symptom*expression*all*favor*0.3*mg/kg*dose*over*0.1*mg/kg*dose*for*Phase*3

! Favorable*safety*and*tolerability*profile*with*no*early*withdrawals*in*the*study;*Safety*

and*PK/PD*profile*consistent*with*Phase*1*healthy*volunteer*and*Phase*2*PNH*studies

! EndCofCPhase*2*meetings*with*FDA*and*other*regulatory*agencies*planned*for*1H19*to*

confirm*Phase*3*design

! Expanded*dataset,*including*pharmacodynamics*and*extension*data,*planned*for*1H19

Zilucoplan*in*gMG:*Phase*2*Top5line*Data*Summary

17

Topics

Introduction

Myasthenia2Gravis2Disease2Overview

Phase222Results

Closing2Remarks

Q&A

Zilucoplan:+A+Convenient+Complement+Inhibitor+for+a+Broad+gMG Population

Zilucoplan

1Soliris(QMG,(ADL(at(12wk(estimated((Ref.(Howard(et(al. Lancet 2017)2Soliris(QMG,(ADL(improvement(at(26wks((Ref.(Howard(et(al.(Lancet 2017)3Soliris(Highlights(of(Prescribing(Information;(http://alexion.com/Documents/Soliris_USPI.aspx

~0.5+mL+(3+kDa)SC+daily+selfJadmin+

120(mL((140(kDa)(

Intravenous(infusion(

every(14(daysADL

QMG

~U1.7

≥7 34%

≥6 39%

ADL

QMG J2.8

@(12wks

@+12wks

@(26wks

@+12wks

(U3*)

≥7 43%

≥6 36%

18

QMG,+ADLMean+δ vs+Placebo1 %+Improvement2

*At(26wks

C5(mAb

C5+Cyclic+Peptide

(U1.9*)

Eculizumab3

UncontrolledMG

(~30k)

Refractory(MG

(~3U5k)

5J8+sec.+

45(min.

Administration Tx+Time Population Mechanism

J2.3

~U2.5

Market'Opportunity:'Extend'Complement'Inhibition'to'More'Patients

SteroidsAcetylcholinesterase0

Inhibitor

Immunosuppressive0

Therapies

IVIG/PLEX

(Crises0or0Chronic)

Target'Complement=Mediated'Damage'Earlier(~50%'of0MG0patients0are0uncontrolled)

Data'source:'IQVIA'market'projections'(93%'retail,'1.5B'LRx'&'Dx'claims,'CDM'~350'hospitals,'PharMetrics'health'plan'150M'pts)Jan020160– Dec020170selection0period0(patients0with0at0least010MG0diagnosis0claim0ICDN100G70.000or0G70.01);050years0history0for0treatment0and0procedures0(starting0Jan02013)

Applied0best0practice0eligibility0controls0and0apply0appropriate0preNscreener/endNtreater0rules

Used0Rx/Dx0intersection0to0project0Rx0and0officeNbased0treatments,0and0projected0hospital0utilization0of0relevant0therapies0(ie. IVIG,0PLEX)0using0CDM0

Segment0size0projected0with0Pharmetrics0Plus0data,0therapy0usage0does0not0use0Pharmetrics0Plus;0therapy0analysis0on0steroid0dosage0used0to0allocate0patients0on0high0dose0steroid0to0uncontrolled

US0Prevalence:0~2000per0million0(~60K0pts)0

19

REGAIN'Population'(Eculizumab)

Zilucoplan Phase'2'Population

Opportunity'to'Treat'~30K'Patients'(U.S.'Only)'with'AChR+'gMG

<10K'pts'~'15%>20K'pts'~'35%

MG0

Diagnosis

20

Zilucoplan:+Designed+for+Everyday+Complement+Control

Positioned+for+Earlier+Use:+Targets*complement1mediated*damage*at*all*stages*of*treatment*paradigm

Convenient:+518*sec*push,*~0.5*mL,*room*temperature;*Experience*comparable*to*daily*insulin*injection

Easy+to+Use:+BD*UltraSafe*Plus™*PFS*with*>13,000*doses*administered*in*zilucoplan clinical*trials;*

91%+of*gMG*patients*interested*in*daily*self1administered*SC*complement*inhibitor1

Accessible:+Pricing*expected*to*enable*broader*access;*Non1refractory and*refractory*patients

Efficacious:+Rapid*and*meaningful*reductions*in*QMG*&*MG1ADL*with*high*proportion*of*patients*

achieving*MSE;*Favorable*safety*and*tolerability

1Data*on*file:*market*research*with*MGFA*(n=372)

Array%of%C5%Inhibitor%Assets%Provides%an%Opportunity%to%Build%a%Transformative%Franchise%in%Neurology%

Zilucoplan%QD

Zilucoplan%XR

Oral%Small%Molecule%C5%Inhibitor

Neuromuscular

Neurodegenerative

Neuropathies/Myopathies

SC%once%daily,%small%peptide%inhibitor,%designed%to%inhibit%C5%systemically%and%locally

Added%convenience%of%SC%once%weekly

Highly%potent,%orally%available

C5%LifecycleNeurology%Disease%TargetsSystemic%&%Local%C5

Potential%of%a%Peptide%Inhibitor%in%TissueNBased%C5%diseases%and%a%FirstNinNClass%Oral%Small%Molecule 21

22

Topics

Introduction

Myasthenia1Gravis1Disease1Overview

Phase121Results

Closing1Remarks

Q&A

For$information,$please$contact:David$LubnerEVP,%Chief%Financial%Officer,%Ra%Pharmaceuticals,%Inc.

dlubner@rapharma.com

Natalie'WildenradtInvestor%Relations,%Argot%Partners

natalie@argotpartners.com