New Ways to Build Muscle for Muscular Dystrophy

GENE THERAPY to INHIBIT MYOSTATIN

MYOSTATIN

•  MYOSTATIN Gene discovered in mouse •  Inhibition or loss leads to muscle enlargement

• Human Gene found in 2004

1997

Baby at 7 months without myostatin

Schuelke, Wagner, Stolz, et al N Engl J Med 2004

Can We Harness this as an approach for Gene Therapy ?

Myostatin Inhibition

Smad 3 Smad 2

Smad 4

Follistatin

FLRG

GASP1

ActRIIB Alk4 /Alk5 co-receptor P

P

P

P

P

P

M M

M M

M M Propeptide Circulating

Propeptide Myostatin Complex

Myostatin Dimer Propeptide Complex

nucleus

Smad Complex

Activation of target genes

Signal Peptide SP

Cleavage

Candidate Genes for Myostatin Inhibition

Comparison of hindlimb Strength in C57/B6 mice

Follistatin Gene (DNA) 1 2 3 4 5 6a 6b

1 2 3 4 5 6b

SP

Adeno-associated Virus (AAV)

FS344

Injection of Leg Muscle

180 days

Treatment of muscular dystrophy mouse

Control Gene Therapy Control Gene Therapy

None Gene Normal Therapy

CK

MOVING TO NON-HUMAN PRIMATE

Can the Mouse Studies Predict Safety and Efficacy in a Clinical Trial ?

FS344 Gene Transfer to Monkey

Follistatin Blood Levels Thigh Circumference Treated

Untreated

AAV1-FS

Control

Untreated Low dose high dose

Gene Therapy

The Clinical Problem •  Quadriceps muscle weakness (Becker Muscular Dystrophy Sporadic Inclusion body myositis)

•  Frequent falls/ loss of ambulation

•  Clinical trial improving quadriceps muscle strength would result in a

“clinically meaningful outcome”

Resistant to Muscle Strength Training

•  Weight training

•  Electrical Stimulation

•  Anabolic Steroids

•  Wyeth sponsored 11 Center Trial (10 USA;1GB) Using MYO-029 antibody to myostatin

–  No Clinical Benefit –  Muscle histology showed a trend toward increased muscle fiber size –  Demonstrated safety of systemic delivery of a

myostatin inhibitor in a clinical trial

Ann Neurology March 11, 2008

Can Follistatin Gene Therapy be Done Safely ?

Clinical Chemistries Monkeys used in Pre-clinical Studies

IMMUNE RESPONSE

Full Examination of Non-Human Primates

•  Slides on each organ evaluated by a board certified veterinary pathologist blinded to treatment group (control vs FS)

•  No treatment-related abnormalities found in heart, liver, lung, spleen, kidney, testis, ovary and uterus (5 &15 months)

Cardiac Studies Post AAV1.FS344 Treatment 15 months

Moving Forward •  FDA has given approval to move to a

clinical trial •  PPMD has supported studies in Becker

muscular dystophy •  Clinical trial will begin in December

2010 - January 2011

Clinical Trial Design •  Six BMD patients will undergo direct

injection of AAV1.MCK.Follistatin into quadriceps muscles (1x1012 vg/muscle)

•  Patients will be followed for six months •  Muscle biopsies will be done at 3 and 6

months – Muscle size will be assessed and any signs of

muscle inflammation/damage •  MRI of quadriceps at 3 and 6 months •  Muscle strength and 6MWT will be assessed

Collaborators Brian Kaspar Louise Rodino K.Reed Clark Kevin Flanigan Zarife Sahenk Chris Walker

Support Parent Project Muscular Dystrophy

The Myositis Association