Extension Study of Ataluren for Nonsense Mutation Cystic Fibrosis

The primary objective of this Phase 3 extension study will be to obtain long-term safety data
to augment the overall safety database. The secondary objectives will be to augment the
efficacy data collected in the double-blind study (PTC124-GD-021-CF).

Inclusion Criteria:

- Completion of study treatment (placebo or active) in the previous Phase 3,
double-blind study protocol (Protocol PTC124-GD-021-CF)

- Evidence of signed and dated informed consent/assent document(s) indicating that the
patient (and/or his parent/legal guardian)has been informed of all pertinent aspects
of the trial.

Exclusion Criteria:

- Known hypersensitivity to any of the ingredients or excipients of the study drug.

- Ongoing participation in any other therapeutic clinical trial