A Phase III Open Label Extension Study to Assess the Long-Term Safety
and Efficacy of Idebenone in Patients with Duchenne Muscular Dystrophy
(DMD) who completed the SIDEROS study

Duchenne Muscular Dystrophy is a condition that affects about 1 in every 3*000
boys. The disease affects the muscles, including
muscles involved in breathing and the heart. There is a need to develop new
treatments for this disease and also to assess the
safety, tolerability and efficacy of these treatments.
Idebenone is a small molecule optimized to facilitate the transport of
electrons within mitochondria ("cellular power plants"), and
contributes to maintaining correct electron flow, which is necessary for the
production of cellular energy. Nerve and muscle cells,
including lung and heart muscle cells, are particularly energy demanding and
are, therefore, more prone to rapid loss of function
or death due to the mitochondria not producing energy properly. Through
preserving mitochondrial function and protecting cells from oxidative damage,
it is believed that idebenone can prevent cell damage and increase the
production of energy within impaired nerve and muscle tissue in DMD patients.

Primary:
* To assess the long-term safety of idebenone in DMD patients who completed the
SIDEROS study.
Secondary:
* To describe the long-term evolution of respiratory function in
idebenone-treated DMD patients who completed the SIDEROS study, classified by
background factors including, but not limited to age, DMD history (e.g. time of
loss of ambulation, mutation type), type of steroid regimen and study treatment
assignment in the SIDEROS study.

Other:
* To assess the feasibility of home-based measurement of respiratory function
with hand-held nmd-1 device.
* To assess the correlation between evolution of respiratory function and
clinically relevant DMD events (bronchopulmonary adverse events, use of
antibiotics, hospitalizations due to respiratory system disorders, treatment
interventions including assisted ventilation, reach of Peak Cough Flow (PCF)
thresholds).

* To assess the correlation between evolution of respiratory function and
health related quality of life outcomes for patients and caregivers.

Open-label, single-group, multi-center extension study with 4 study visits
scheduled every 6 months (Visit 1/Baseline, Visit 2/Week 26, Visit 3/Week 52
and Visit 4/Week 78). Visit 8/Week 78 in SIDEROS study corresponds to SIDEROS-E
Visit 1/Baseline. At the end of the SIDEROS-E study, patients will have the
possibility to continue treatment with idebenone under different settings,
adapted to individual countries* regulations, until the drug is commercially
available for DMD indication.

NA

Breathing tests:
For the breathing test, you will need to breathe into a special machine. You
will be shown how to do it but here is a description of
what to do: First you will need to take a deep breathe in and make sure that
your lips are sealed around the mouthpiece. You will
then need to blow out into the machine as fast as you can until your lungs are
empty. How long it will take you to do this test
depends on how big your lungs are but it usually takes a few seconds. You might
also be asked to breathe in again and breathe
out slowly for as long as you can. You might need to have a clip put on your
nose so that you are not breathing out through your nose at the same time or
you might need a small mask on your face if you cannot fully seal your lips on
the mouthpiece.
You will be given a small machine called the nmd1 device to take home with you
to use between visits. This is to measure the
same things as the hospital tests measure, but at home. The respiratory
therapist will show you how to use this machine. You
should not feel unwell when you are doing these tests at hospital and at home
but you might feel a little bit dizzy or breathless
because you have been breathing so deeply. You will be allowed to have 5 minute
breaks for a rest between the examinations.
The breathing tests including the home examinations with the nmd1 device are
harmless and will simply measure how well and
how forcefully you can breathe in and out. For the breathing tests, it is very
important that you follow the instructions given by the person in charge at the
hospital and in the Quick Reference Guide for the tests you do at home. The
breathing tests will be done at hospital at each visit with the hospital based
device and the handheld nmd1 device and at home with the nmd1
handheld device once a week until end of treatment.

Electrocardiogram (ECG)
There is one test for measuring the heart, an electrocardiogram (ECG). This
test is also noninvasive and not painful. The
electrocardiogram (ECG) is a tracing of your heart beating, made by recording
tiny changes of electricity produced by your heart at
the surface of the skin. To record these changes electrode stickers will be put
on your chest with wires attached to them. It will take
about 5-10 minutes. 2 ECGs will be recorded: One before you start the treatment
at Visit 1 / Baseline and one when you have finished the treatment.

Blood sample analysis
Blood samples will be collected for examination at each visit. Collecting the
blood samples will be the only procedure that might
cause discomfort during the study. There will be approximately 10 ml collected
at each study visit, the equivalent of about 2
teaspoons. Your blood samples will be sent out of
the hospital on the same day they have been collected to a central laboratory,
based in the United Kingdom, for analysis. Your
blood samples will be fully used to perform the analyses and will not be
retained neither at the hospital neither at the central
laboratory.

Benefits:
It is not yet fully known how idebenone will help your illness, but through
data collected until now in previous studies, it is believed
that idebenone will slow the decline of your respiratory function. Also, other
people with a similar condition may benefit from the
knowledge obtained from this research study. However it is not guaranteed that
your participation in the study will bring you any
benefit.