ACTRIIA-FcrebalancesBMPandactivin/TGF-βsignalingtoattenuateexperimentalpulmonaryhypertension

Lai-MingYung,Ph.D1;R.ScottPearsall,Ph.D2;GeoffreyBocobo,B.S.1;DianneS.Sako2;TeresaDinter,B.S.1;Ravindra Kumar,Ph.D2;

PaulB.Yu,M.D.,Ph.D.1

1DivisionofCardiovascularMedicine,Brigham&Women’sHospitalandHarvardMedicalSchool,Boston,MA;

2AcceleronPharma,Cambridge,MA

BMPRII BMPR2 HPAHALK1 ACVRL1 HHT2-HPAHENG ENG HHT1SMAD4 SMAD4 JP-HTSMAD9 SMAD9 HPAHBMP9 GDF2 HHT5

SMAD2/3

Nucleus

P PP P

I II

SMAD1/5/9

SMAD1/5/9

P

PPPP

III

SMAD2/3P

TGF

SMAD4

SMAD1/5/9

P

SMAD4CAGA

SMAD2/3P

SMAD4

*

BMPTGF BMP

TGFBRIIACTRIIA

ALK4ALK5ALK7

ALK1ALK2ALK3

BMPRII

Endoglin

activin

BRE

MutationsofHeritablePAHsyndromesimplicatelossofBMPfunctioninpulmonaryvasculardisease

myogenicandfibrogenic differentiation

vascularhomeostasis

PAHischaracterizedbydeficientBMPsignalingandexaggeratedTGFβ/activinsignaling

- GeneticsimplicatesdeficientBMP9-BMPRII-ALK1-ENG-SMAD1/5/9axis

- Non-geneticformsofPAHexhibitdeficientBMP,andexaggeratedTGFβ/activinsignaling

- PatternrecapitulatedinmultipleanimalmodelsofPH

- Approvedtherapiesappeartoimprovethisbalance

SMAD2/3

Nucleus

P PP P

I II

SMAD1/5/9

SMAD1/5/9

P

PPPP

III

SMAD2/3P

TGF

SMAD4

P

SMAD4CAGA

SMAD2/3P

SMAD4

*

BMPTGF BMP

TGFBRIIACTRIIA

ALK4ALK5ALK7

ALK1ALK2ALK3

BMPRII

Endoglin

activin

BRE

SMAD1/5/9

YungLM,AJRCCM2016YanY,Int JCardiol 2016LongL,NatMed2015

Yndestad A,JAppl Physiol 2009AtkinsonL,Circ 2002

Ogo T,Circ 2013YangJ,Circ Res2010

Whatistheimpactofselectiveactivin/GDFblockadeinpulmonaryarterialhypertension?

BMP9 BMP10 activinA activinB TGFβ1 TGFβ3 TGFβ2GDF8 GDF11BMP2 BMP4 BMP6 BMP7 activinACBMP12

SMAD1/5/9 SMAD2/3

ACTRIIA-Fc(ACE-011/Sotatercept)

TGFBRII-FcYungLMetal.AJRCCM2016

myogenicandfibrogenic differentiationvascularhomeostasis

Hypothesis:BlockadeofactivinligandsattenuatespulmonaryvascularremodelingbyrebalancingSMAD1/5/8vs.SMAD2/3signaling

*Primaryligandsinhibited

62.3 57.9

36.4 41.6

0.9

66.9**

ACTRIIA-Fc(10mg/klg)

100%

Sildenafil(60mg/day)

25.8**

7.3*

Vehicle

1.4

PartiallymuscularizedNon-muscularized

Completelymuscularized

WeightR

atio

mmHg

P<0.001 P<0.001P<0.05 P<0.05

RV/LV+SMPAP

0

10

20

30

40

50

Vehicle ACTRIIA-Fc Sildenafil0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Vehicle ACTRIIA-Fc Sildenafil

ImpactofACTRIIA-Fc(15mg/kgS.C.twiceweeklyx4weeks)prophylaxisinratstreatedwithMCT(60mg/kg)

*p≤0.05vs.control**p ≤0.01vs.control

72.5 67.4

27.4 31.6

1.0

69.3**

ACTRIIA-Fc(10mg/kg)

100%

Sildenafil(60mg/day)

29.3**

1.4*

Vehicle

0.1

PartiallymuscularizedNon-muscularized

Completelymuscularized

WeightR

atio

mmHg

P<0.001 P<0.001P<0.001 P<0.001

RV/LV+SMPAP

ImpactofACTRIIA-Fc(10mg/kgweeklyx4weeks)prophylaxisinratstreatedwithSUGEN5416(200mg/kg)andhypoxia

0

10

20

30

40

50

Vehicle ACTRIIA-Fc Sildenafil0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Vehicle ACTRIIA-Fc Sildenafil

*p≤0.05vs.control**p ≤0.01vs.control

ImpactofACTRIIA-FcprophylaxisonPVremodelinginSU-Hx rats

Sugenhypoxia,lunghistology(αSMA/elastinStaining)

SUGEN-HypoxiaSUGEN-Hypoxia+

SildenafilSUGEN-Hypoxia+

ACTRIIA-Fc

SU-Hx Model Treatment nControl Vehicle 8

ACTRIIA-Fc

1mg/kgtwice weekly 7

3 mg/kgtwiceweekly 7

10mg/kgtwiceweekly 8

SU-Hx (3 weeks)

Echo RV functionRight heart catheterizationFulton’s IndexPV and RV Histology

Normobaric hypoxia (FIO2 = 0.10)SU5416 (20 mg/kg S.C., weekly)

Sprague Dawley Rat

Normoxia (3 weeks)

ImpactofACTRIIA-FconprogressionofestablishedPHinSU-Hx rats

ACTRIIA-FcSU5416

one-wayANOVAdosetrendp=0.03

SU-Hx 1 3 100

20

40

60

RVS

P (m

mH

g)

p=0.02

(8) (7) (7) (8)

ActRII-Fc (mg/kg twice weekly)

one-wayANOVAdosetrendp=0.05

ACTRIIA-FcattenuatesPHprogressioninSU-Hx rats

69.3**

29.3**

SU-Hx 1 3 100

50

100

Perc

ent o

f Tot

al V

esse

ls

RAP-011 (mg/kg twice weekly)

18.531.9

42.311.831.2

18.8 22.427.5

68.047.9

28.845.2

*one-wayANOVAtrendp=0.05

SU-Hx 1 3 100.0

0.1

0.2

0.3

0.4

0.5

RV/

(LV+

S) p=0.05

(8) (7) (7) (8)

ActRII-Fc (mg/kg twice weekly)

Non -muscularized

Partially muscularized

Completely Muscularized

ACTRIIA-Fc(mg/kg twice weekly)

one-way ANOVA trend p = 0.01

one-way ANOVA trend p = 0.05

SU-Hx 1 3 100

20

40

60

80

100

% F

ully

Mus

cula

rized

Ves

sels

ActRIIa-Fc (mg/kg twice weekly)

p=0.05

(8) (7) (7) (8)

SU-Hx 1 3 100

20

40

60

Med

ial w

all t

hick

ness

in

dex

(%)

ActRII-Fc (mg/kg twice weekly)

(8) (7) (7) (8)

p=0.02

SU-Hx 1 mg/kg

SMAvWF

3 mg/kg 10 mg/kg

50 µm

ACTRIIA-Fcattenuatesintimal-medialremodelinginSU-Hx rats

DAPI

ACTRIIA-Fcde-repressesactivininhibitionofBMP9signaling

1 1

BMP9activinA

ACTRIIA-Fc

---

+--

++-

+++

-+-

BMP9activinB

ACTRIIA-Fc

---

+--

++-

+++

-+-

BRE-Luciferase

Activ

ity(R

LU)

BRE-Luciferase

Activ

ity(R

LU)

BMPResponseElement(BRE-Luciferase)activityinA204reportercellline

%ReductioninmPAPAgent

Bosentan1 21 30

Sildenafil4 24 18

BeraprostNP2 255 28

ACTIIA-Fc4 56 47

%ReductioninRVHRV/(LV+S)

Monocrotaline - Prevention

%ReductioninmPAPAgent

Macitentan3 365 31

Sildenafil4 22 10

BeraprostNP2 275 32

ACTRIIA-Fc4 51 54

%ReductioninRVHRV/(LV+S)

SUGEN-Hypoxia- Prevention

%ReductioninRVSPAgent

10 19

Riociguat1 10 20

Tadalafil +Macitentan2

28 28

ACTRIIA-Fc3 33 30

%ReductioninRVHRV/(LV+S)

SUGEN-Hypoxia– Therapeutic

Sildenafil1

1.Langetal.PLoS One.2012;7(8):e43433Sildenafil50mg/kg/d;Riociguat 10mg/kg/d

2Boucherat etal.SciRep.2017Jul3;7(1):4546Tadalafil 10mg/kg/d;Macitentan 30mg/kg/d

3.Current study;10mg/kgtwice weekly

1.Clozel etal Exp.Biol andMed(2006)231:967-973;Bosentan 300mg/kg/d2.Akagi etalJCardiovasc Pharmacol 2016;67;290-298;Beraprost NP150μg/kg3.ShinoharaetalAmJPhysiol LungCellMol Physiol 2015;Macitentan 30mg/kg/d4.RAP-011andSildenafil(60mg/kg/d)weretestedinsamestudyatCorDynamics5.Rightventricularsystolicpressure

Comparison of ACTRIIA-Fc to approved therapies in PH models

Summary1. ACTRIIA-Fcisapotentiallymechanism-targeted,non-vasodilatorPAH

therapythatpotentlyinhibitsneo-intimalandmedialremodeling.

2. ACTRIIA-Fcinhibitssignalingofactivins/GDFsandmayaugmentBMPs;multiplemechanismsofactionand cellulartargetsbeingconsidered.

3. Sotatercept hasfavorablepharmacokinetics,dosedSCeverythreeweeks.

3.Humanclinicalexperienceincludesnearly400patientsacross13trials.

4. Welltolerated at0.3,0.7,and1.5mg/kginhumansubjects,correspondingtohumanequivalentdosesof1.8,4.2and10mg/kginrats,overlappingwithefficaciousdosesinratmodels.

6.Phase2studiesforPAHareplanned.

AcknowledgementsYulaboratory– BWHCardiologyLai-MingYung,PhDPeiran Yang,PhDIvanaNikolic,MDGeoffBocobo,BSTeresaDinter,BSMeganMcNeil,BSLucaTroncone,PhD

Acceleron PharmaRavindra Kumar,Ph.DR.ScottPearsall,Ph.DDianneS.Sako,B.S.

FundingNHLBIR01-HL131910NHLBIR42-HL132742B-BICDRIVEGRANTFondationLeducq

Lai-Ming Yung, PhD

Teresa Dinter, BS

Geoff Bocobo, BS

Brian PeiranYang, PhD

SMAD2/3

Nucleus

P PP P

I II

SMAD1/5/9

SMAD1/5/9

P

PPPP

III

SMAD2/3P

TGF

SMAD4

SMAD1/5/9

P

SMAD4CAGA

SMAD2/3P

SMAD4

*

BMPTGF BMP

TGFBRIIACTRIIA

ALK4ALK5ALK7

ALK1ALK2ALK3

BMPRII

Endoglin

activin

BRE

ACTRIIA-Fcfusionprotein(RAP-011/Sotatercept)isanactivin/GDFligandtrap

ACTRIIA-Fc(RAP-011/Sotatercept)trapsactivinA,activinB,

GDF8,GDF11

BMP BMP

BMP BMP

ACTRIIA-Fc+-