Clinical Study to Evaluate the Efficacy and Safety of Givinostat in Ambulant Patients With Duchenne Muscular Dystrophy

Givinostat or placebo oral suspension (10 mg/mL) will be administered orally as 2 oral doses
daily while the subject is in fed state, according to the child's weight.

Study drug should be permanently stopped if any of the following occur:

- severe drug-related diarrhoea;

- any drug-related Serious Adverse Event;

- QTcF >500 msec;

- platelets count ≤50 x 109/L.

Study drug should be temporarily stopped if any of the following occur:

- platelets count <75 x 109/L but >50 x 109/L (the treatment should be temporarily stopped
and a platelets count has to be performed and re-tested until platelets will be
normalized);

- moderate or severe diarrhoea.

In case the study drug was temporarily stopped, the study drug can be resumed at a level 1/3
smaller than the one at which the Adverse Event leading to temporary stop occurred, once
platelets are normalized or diarrhoea is mild (if treatment was stopped for moderate or
severe diarrhoea).

Two interim analyses are planned and will be conducted by the IDMC in order to ensure study
integrity.

Inclusion Criteria:

1. Are an ambulant male aged ≥6 years at randomisation with DMD characteristic clinical
symptoms or signs (e.g., proximal muscle weakness, Gowers' maneuver, elevated serum
creatinine kinase level) already present at screening;

2. Have DMD diagnosis confirmed by genetic testing;

3. Are able to give informed assent and/or consent in writing signed by the subject
and/or parent/legal guardian (according to local regulations);

4. Are able to complete 2 Four Stairs Climb test (4SC) screening assessments; the results
of these tests must be within ±1 second of each other;

5. Have the mean of 2 screening 4SC assessments ≤8 seconds;

6. Have time to rise from floor between ≥3 and <10 seconds at screening

7. Have manual muscle testing (MMT) of quadriceps at screening Grade - 3;

8. Have used systemic corticosteroids for a minimum of 6 months immediately prior to the
start of study treatment, with no significant change in corticosteroids type or dosage
or dosing regimen (excluding changes related to body weight change) for a minimum of 6
months immediately prior to start of study treatment and a reasonable expectation that
dosage and dosing regimen will not change significantly for the duration of the study.

Exclusion Criteria:

1. Have exposure to another investigational drug within 3 months prior to the start of
study treatment;

2. Have exposure to idebenone within 3 months prior to the start of study treatment;

3. Have exposure to any dystrophin restoration product (e.g., Ataluren, Exon skipping)
within 6 months prior to the start of study treatment;

4. Use of any pharmacologic treatment, other than corticosteroids, that might have had an
effect on muscle strength or function within 3 months prior to the start of study
treatment (e.g., growth hormone); Vitamin D, calcium, and any other supplements will
be allowed as long as their intake has been stable for 3 months prior to the start of
study treatment; Testosterone will also be allowed as long as their intake has been
stable for 3 months prior to the start and testosterone dose and regimen have been
stable for at least 6 months and circulating testosterone levels are within the normal
ranges for the subject's age;

5. Have surgery that might have an effect on muscle strength or function within 3 months
before study entry or planned surgery at any time during the study;

6. Ankle joint contractures due to a fixed loss of ≥10 degrees of dorsiflexion from
plantagrade assuming a normal range of dorsiflexion of 20 degree;

7. Change in contracture treatment such as serial casting, contracture control devices,
night splints, stretching exercises (passive, active, self) within 3 months prior to
enrollment, or expected need for such intervention during the study;

8. Have presence of other clinically significant disease, which, in the Investigator's
opinion, could adversely affect the safety of the subject, making it unlikely that the
course of treatment or follow-up would be completed, or could impair the assessment of
study results;

9. Have a diagnosis of other uncontrolled neurological diseases or presence of relevant
uncontrolled somatic disorders that are not related to DMD;

10. Have platelets count at screening < Lower Limit of Normal (LLN);

11. Have symptomatic cardiomyopathy or heart failure (New York Heart Association Class III
or IV) or left ventricular ejection fraction <50% at screening;

12. Have a current or history of liver disease or impairment;

13. Have inadequate renal function, as defined by serum Cystatin C >2 x the upper limit of
normal (ULN);

14. Have Triglycerides > 300 mg/dL (3.42 mmol/L) in fasting condition at screening visit;

15. Have a baseline QTcF >450 msec, or history of additional risk factors for torsades de
pointes (e.g., heart failure, hypokalemia, or family history of long QT syndrome);

16. Have a psychiatric illness/social situations rendering the potential subject unable to
understand and comply with the muscle function tests and/or with the study protocol
procedures;

17. Have any known allergic reaction to givinostat or any of its excipients.

At the discretion of the Investigator, subjects not meeting inclusion/exclusion criteria
may be re-screened twice with an interval of at least 3 months between assessments.