Myotubular Trust Family Conference, July 12th, 2014€¦ · present in all tissues lipid...
Transcript of Myotubular Trust Family Conference, July 12th, 2014€¦ · present in all tissues lipid...
Gene replacement therapy for myotubular myopathy
Anna Buj Bello
Myotubular Trust Family Conference, July 12th, 2014
Gene Therapy
Diseased cell
Gene mutation
Treatment of a disease by the administration of nucleic acids (DNA, RNA) in cells
Replacing or supplementing non-functional / mutated genes with
« healthy » genes
Patient
Diseased muscle
In human: ~ 640 muscles
12/07/2014
Gene Therapy
Derived from viruses
Produced in microscopic factories : cells
Carry a normal copy of the gene
Diseased cell Corrected cell
Vectors
12/07/2014
Ex vivo
In vivo
VECTOR
TRANSGENE
VECTORS PATIENT’S CELLS
TRANSDUCED
CELLS
Gene Therapy
12/07/2014
Identify the disease model
Administrate the vector to the
animal model:
- Route of administration
- Dose to be injected
- Determine evaluation tests
- Anticipate secondary effects
Verify the efficacy of the vector:
proof-of-concept
Therapeutic concept Preclinical development Clinical trials
Proof-of-concept
12/07/2014
Myotubular myopathy: animal models
Therapeutic concept Preclinical development Clinical trials
Identify the disease model
Mouse model (KO) - 2002
∆4
Mtm1 exon 4
Absence of myotubularin
Dog model (natural) - 2010
Misense mutation
MTM1 exon 7
Myotubularin (N155K) present but
strongly decreased
#
12/07/2014
Myotubular myopathy : gene
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
100 Kb
>300 different mutations
MTM1 gene - 1996: X chromosome
Protein: MYOTUBULARIN
present in all tissues
lipid phosphatase
MUTATIONS : loss or reduction of protein level
12/07/2014
Therapeutic vector
25 nm
ITR ITR
rep cap
rAAV (adeno-associated vector)
AAV: Non pathogenic virus in humans
Rep–Cap genes replaced by the MTM1 gene
AAV8-Mtm1 (mouse): research grade vector
AAV8-cMTM1 (dog): GMP-like vector
AAV8-hMTM1 (human): GMP vector
MTM1
12/07/2014
Gene therapy: proof of concept
Local delivery (intramuscular) - 2008
Correction of muscle histology (morphology)
Increase in muscle strength
MTM -treated MTM Healthy
Injection in muscle posterior leg (TA)
Analysis + 4 weeks
rAAV1-Mtm1
Mtm1 mKO
12/07/2014
WT+saline KO+saline WT+saline KO Early+AAV
5 weeks 6 months
HE
N
AD
H-T
R
DH
PRα
KO Late+AAV
Muscle histology
Correction of all muscles:
Morphology
Strength
Late stage of disease
12/07/2014
Gene therapy: dose-finding study
rAAV8-Mtm1
systemic administration
Su
rviv
al ra
te (
%)
Days
100
80
60
40
20
0 0 30 60 90 120
Dose 1: 100% survival at 3 months
Dose 2: 50% survival at 3 months
Days B
od
y w
eig
ht
(g)
30
25
20
10
0 0 30 60 90 120
15
5
WT + saline
KO + saline
KO + AAV High 1
KO + AAV Low 2
Dose 1: quasi-normalisation body weight
Dose 2: body weight not fully corrected
Therapeutic dose for long-term phenotype rescue (dose 1)
12/07/2014
Acknowledgements
Laurine Buscara
Karine Poulard
Nathalie Danièle
Romain Joubert
Christelle Moal
Thibaud Jamet
Yohann Garnier
Julie Marchant
Martin K. (Casey) Childers University of Washington, USA
Alan H. Beggs Children’s Hospital Boston, USA
Philippe Moullier
INSERM U649, Nantes
Atlantic Gene Therapies
Carole Masurier
Common Facilities
Genethon Bioprod
Fulvio Mavilio
Michael Lawlor Children’s Hospital and Medical
College of Wisconsin, USA