An Extension Study of Ataluren (PTC124) in Participants With Nonsense Mutation Dystrophinopathy

Inclusion Criteria:

- Completion of study treatment in the previous Phase 3, double-blind study protocol
(Protocol PTC124-GD-020-DMD).

- Evidence of signed and dated informed consent/assent document(s) indicating that the
participant (and/or his parent/legal guardian) has been informed of all pertinent
aspects of the trial. Note: If the study candidate is considered a child under local
regulation, a parent or legal guardian must provide written consent prior to
initiation of study screening procedures and the study candidate may be required to
provide written assent. The rules of the responsible Institutional Review
Board/Independent Ethic Committee (IRB/IEC) regarding whether one or both parents must
provide consent and the appropriate ages for obtaining consent and assent from the
participant should be followed.

- In participants who are sexually active, willingness to abstain from sexual
intercourse or employ a barrier or medical method of contraception during the period
of study drug administration and 6-week follow-up period.

- Willingness and ability to comply with scheduled visits, ataluren administration plan,
study procedures, laboratory tests, and study restrictions.

Exclusion Criteria:

- Known hypersensitivity to any of the ingredients or excipients of the study drug
(Litesse® UltraTM [refined polydextrose], polyethylene glycol 3350, Lutrol® micro F127
[poloxamer 407], mannitol 25C, crospovidone XL10, hydroxyethyl cellulose, vanilla,
Cab-O-Sil® M5P [colloidal silica], magnesium stearate).

- Ongoing participation in any other therapeutic clinical trial.

- Prior or ongoing medical condition (for example, concomitant illness, psychiatric
condition, behavioral disorder, alcoholism, drug abuse), medical history, physical
findings, electrocardiogram (ECG) findings, or laboratory abnormality that, in the
investigator's opinion, could adversely affect the safety of the participant, makes it
unlikely that the course of treatment or follow-up would be completed, or could impair
the assessment of study results.