The 6MWD test is a non-encouraged test performed in a 30 meters long flat corridor, where the participant is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed. Ambulation was assessed via the 6MWD test following standardized procedures. Participants were not permitted to use assistive devices (walker, long leg braces, or short leg braces) during the 6MWD test. Participants with confirmed loss of ambulation at a particular visit were assigned a 6MWD result of 0. Baseline was defined as the maximum measurement of valid Day 1 and Day 2 6MWD values. Least square (LS) mean and standard error (SE) was calculated using the mixed-model repeated measures (MMRM).

The 6MWD test is a non-encouraged test performed in a 30 meters long flat corridor, where the participant is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed. Ambulation was assessed via the 6MWD test following standardized procedures. Participants were not permitted to use assistive devices (walker, long leg braces, or short leg braces) during the 6MWD test. Participants with confirmed loss of ambulation at a particular visit were assigned a 6MWD result of 0. Baseline was defined as the maximum measurement of valid Day 1 and Day 2 6MWD values. LS mean and SE was calculated using the MMRM.

The 6MWD test is a non-encouraged test performed in a 30 meters long flat corridor, where the participant is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed. Ambulation was assessed via the 6MWD test following standardized procedures. Participants were not permitted to use assistive devices (walker, long leg braces, or short leg braces) during the 6MWD test. Participants with confirmed loss of ambulation at a particular visit were assigned a 6MWD result of 0. Baseline was defined as the maximum measurement of valid Day 1 and Day 2 6MWD values. LS mean and SE was calculated using the MMRM.

The 6MWD test is a non-encouraged test performed in a 30 meters long flat corridor, where the participant is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed. Ambulation was assessed via the 6MWD test following standardized procedures. Participants were not permitted to use assistive devices (walker, long leg braces, or short leg braces) during the 6MWD test. Participants with confirmed loss of ambulation at a particular visit were assigned a 6MWD result of 0. Baseline was defined as the maximum measurement of valid Day 1 and Day 2 6MWD values. LS mean and SE was calculated using the MMRM.

The FEV1 is the volume of air forcibly exhaled in one second and is measured using forced expiratory air spirometry. Change in ppFEV1 at Week 48 was defined as the average between the change from baseline at Week 40 and that at Week 48. Baseline for ppFEV1 was defined as an average of ppFEV1 at Screening (Weeks -4 to -1) and Baseline (Day 1) visits.

The 6MWD test is a non-encouraged test performed in a 30 meters long flat corridor, where the participant is instructed to walk as far as possible, back and forth around two cones, with the permission to slow down, rest, or stop if needed. Ambulation was assessed via the 6MWD test following standardized procedures by measuring the 6MWD in meters. Participants were not permitted to use assistive devices (walker, long leg braces, or short leg braces) during the 6MWD test. Participants with confirmed loss of ambulation at a particular visit were assigned a 6MWD result of 0. Baseline and Week 48 6MWD values are each the average of two valid 6MWD values, or a single available value if one was missing.

A TEAE is any untoward medical occurrence or undesirable event(s) experienced in a participant that begins or worsens following administration of the study drug or study treatment, whether or not considered related to the treatment by the Investigator. A serious adverse event (SAE) was an adverse event (AE) resulting in any of the following outcomes or deemed significant for any other reason, death, initial or prolonged inpatient hospitalization, life-threatening experience (immediate risk of dying), or persistent or significant disability/incapacity not related to nmDBMD. AEs included both SAEs and non-serious AEs. AEs were classified according to National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0 (CTCAE) and coded using the Medical Dictionary for Regulatory Activities (MedDRA). A summary of serious and all other non-serious adverse events, regardless of causality, is located in the Reported Adverse Events module.

Laboratory parameters include hematological, serum biochemistry, adrenal laboratories, and urine data.

Physical findings include weight, physical examination data, systolic and diastolic blood pressure, radial pulse rate, and body temperature.

A TEAE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship that occurred or worsened in the period extending from the first dose of study drug to 6 weeks after the last dose of study drug. A serious adverse event (SAE) was an adverse event (AE) resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. AEs included both SAEs and non-serious AEs. AE severity was graded as follows: Grade 1: mild; Grade 2: moderate; Grade 3: severe; Grade 4: life-threatening; Grade 5: fatal. A TEAE was considered related if in the opinion of the Investigator it was possibly or probably caused by the study drug. A summary of other non-serious AEs and all SAEs, regardless of causality is located in the Adverse Events module.

A TELA is any abnormal laboratory value that started or worsened after administration of study drug. Abnormal values were defined as values outside normal range. Values considered abnormal included -Hepatic: Serum total bilirubin ≥1.5\*upper limit of normal (ULN); serum gamma glutamyl transferase \>2.5\*ULN; serum alanine aminotransferase increase of \>150 units/liter (U/L) without increased creatine kinase; -Adrenal: plasma adrenocorticotropic hormone \>ULN (normal cortisol); -Renal: serum cystatin C \>1.33 milligrams (mg)/L; serum creatinine \>ULN-1.5\*ULN for age; serum blood urea nitrogen ≥1.5\*ULN; urine protein:creatinine \>0.40 mg/deciliter (dL):mg/dL; urine protein:osmolality \>0.30 mg/L:milliosmoles/kilogram; urine blood 2+; - Serum Electrolytes: serum sodium \>150 millimoles (mmol)/L, \<130 mmol/L; serum potassium \>5.5, \<3.0 mmol/L; serum magnesium \>1.23 mmol/L, \<0.5 mmol/L; total serum calcium \>2.9 mmol/L, \<2.0 mmol/L; serum phosphorous \<0.8 mmol/L; serum biocarbonate- \<16 mmol/L.

Spirometry was used to assess pulmonary function by measuring the percentage of predicted function, which was determined on the basis of the height value obtained at the same study visit, for FEV1 (the amount of air that can be exhaled in 1 second). Spirometry was assessed by using current guidelines of the American Thoracic Society (ATS) and European Respiratory Society (ERS). Baseline was the average of percent-predicted FEV1 at screening and randomization.

Spirometry was used to assess pulmonary function by measuring the percentage of predicted function, which was determined on the basis of the height value obtained at the same study visit, for FEV1 (the amount of air that can be exhaled in 1 second). Spirometry was assessed by using current guidelines of the American Thoracic Society (ATS) and European Respiratory Society (ERS). The percentage of change in percent-predicted of FEV1 was calculated as follows: (\[percent-predicted FEV1-Baseline percent-predicted FEV1\]/Baseline percent-predicted FEV1)\*100. Baseline was the average of percent-predicted FEV1 at screening and randomization. A negative change from Baseline indicates that percent-predicted of FEV1 decreased.

Convulsive seizure frequency per 28 days is defined as total number of convulsive seizures reported during the period divided by number of days during the period seizures were assessed, multiplied by 28. Percent change from Baseline will be defined as the frequency of seizures per 28 days during the Ataluren Treatment Period minus frequency of seizures per 28 days at Baseline, divided by the frequency of seizures per 28 days at Baseline, multiplied by 100. Negative percent change from Baseline indicates improvement.

Convulsive seizure frequency per 28 days is defined as total number of convulsive seizures reported during the period divided by number of days during the period seizures were assessed, multiplied by 28. Percent change from Baseline will be defined as the frequency of seizures per 28 days during the Placebo Treatment Period minus frequency of seizures per 28 days at Baseline, divided by the frequency of seizures per 28 days at Baseline, multiplied by 100. Negative percent change from Baseline indicates improvement.

An adverse event (AE) was as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Serious adverse event (SAE): an AE that met at least 1 of the following criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, persistent or significant disability/incapacity or substantial disruption of the ability to conduct normal life functions, congenital anomaly/birth defect, important medical event. A TEAE was defined as an AE that occurred or worsened while on ataluren (on or after first dose of ataluren) up to 4 weeks after the last dose. A summary of all SAEs and Other AEs (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.

The mean dystrophin protein levels were measured by ECL. Dystrophin levels are reported by muscle group (gastrocnemius, tibialis anterior, and across muscle locations). Results below the limit of quantitation were imputed as half of lower limit of quantitation (LLOQ). LLOQ = 0.5 micrograms (μg)/milliliter (mL)

The percent change in dystrophin level from baseline in ambulatory nonsense mutation duchenne muscular dystrophy (nmDMD) participants after treatment with ataluren for 40 weeks was analyzed using quantitative assay (ECL).The least square (LS) mean and 90% confidence interval (CI) were analyzed from a mixed-model repeated measures (MMRM) with factors of muscle locations and visits as fixed effects, and participants as a random effect.

A TEAE was any untoward medical occurrence or undesirable event that begins or worsens following administration of study drug, whether or not considered related to study drug by Investigator. An SAE was an adverse event (AE) resulting in any of the following outcomes or deemed significant for any other reason, death, initial or prolonged inpatient hospitalization, life-threatening experience (immediate risk of dying) or persistent or significant disability/incapacity not related to dystrophinopathy. An event was not reported as an SAE, if event was exclusively a relapse or expected change or progression of baseline dystrophinopathy. AEs included both SAEs and nonserious AEs. AEs classified according to National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 and coded using Medical Dictionary for Regulatory Activities. A summary of SAEs and all non-serious AEs, regardless of causality, is located in the Reported Adverse Events section.

Clinical laboratory results that were considered clinically meaningful were to be determined by the Investigator and Sponsor. Biochemistry parameters included sodium, potassium, chloride, bicarbonate, blood urea nitrogen, creatinine, magnesium, calcium, phosphorus, uric acid, glucose, total protein, albumin, bilirubin (total, direct, and indirect), aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, creatine kinase, lactate dehydrogenase, alkaline phosphatase, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, and cystatin C. Hematology parameters included white blood cell count with differential, hemoglobin, hematocrit, other red cell parameters, and platelet count. Urinalysis parameters included pH, specific gravity, glucose, ketones, blood, protein, urobilinogen, bilirubin, nitrite, and leukocyte esterase. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

ECG results that were considered clinically meaningful were to be determined by the Investigator. A summary of other non-serious AEs and all serious AEs, regardless of causality is located in Reported AE section.

Dose-limiting toxicity was measured through clinical evaluations for potential hepatic and renal toxicities. The clinical evaluations included the following: * Hepatic: The participant's medical history, hepatitis screening results, all clinical blood values (particularly serum bilirubin, gamma-glutamyl transferase \[GGT\], aspartate aminotransferase \[AST\], and alanine aminotransferase \[ALT\] values), and all concomitant medications were reviewed. * Renal: The participant's medical history, all clinical blood and urine renal values, serum electrolytes, medications, and potential pre- or post-renal conditions were reviewed.

MNREAD Acuity Chart can only be used to assess participants ≥8 years old. MNREAD Acuity Chart measures reading speed as a function of print size in participants with normal and low vision. The test consists of short sentences with print size decreasing by 0.1 log unit steps from a maximum of 1.3 logarithm of the minimum angle of resolution (logMAR) (equivalent to 20/400 or 6/120 when viewed at 40 centimeters \[cm\]) to -0.5 logMAR (equivalent to 20/6 or 6/2). An MNREAD Acuity Chart curve of reading speed vs print size has a typical shape for normally sighted persons and many low-vision individuals. This curve is characterized by 3 summary values. At large print sizes, reading speed remains fairly constant, forming a plateau that represents the maximum reading speed. As the print size decreases, a critical print size (CPS) is reached at which reading speed begins to decline rapidly. Finally, the smallest print size that can be read is defined as the reading acuity (RA).

Nasal transepithelial potential difference (TEPD) was assessed in each participant using standardized techniques. Warmed solutions of Ringer's solution, amiloride, chloride-free gluconate, isoproterenol, and adenosine triphosphate (ATP) were perfused for ≥3-minute sequentially through a nasal catheter while a voltage tracing was recorded. Total chloride transport was computed for each nostril. The total chloride transport values were calculated by subtracting the voltages at the end of a perfusion from the voltage at the end of an earlier perfusion (isoproterenol - amiloride). The average of the values for each nostril was computed. If the assessment was available in only 1 nostril, this value was used as if it were the average of both nostrils. Baseline data for Cycle 1 and Cycle 2 and change from Baseline data at Day 14 of Cycles 1 and 2 are presented.

Nasal TEPD was assessed in each participant using standardized techniques. Warmed solutions of Ringer's solution, amiloride, chloride-free gluconate, isoproterenol, and ATP were perfused for ≥3-minute sequentially through a nasal catheter while a voltage tracing was recorded. Total chloride transport was computed for each nostril. The total chloride transport values were calculated by subtracting the voltages at the end of a perfusion from the voltage at the end of an earlier perfusion (isoproterenol - amiloride). The average of the values for each nostril was computed. If the assessment was available in only 1 nostril, this value was used as if it were the average of both nostrils. Response to study treatment defined as an increase in total chloride transport as indicated by a change of at least -5 mV in nasal TEPD.

Nasal TEPD was assessed in each participant using standardized techniques. Warmed solutions of Ringer's solution, amiloride, chloride-free gluconate, isoproterenol, and ATP were perfused for ≥3-minute sequentially through a nasal catheter while a voltage tracing was recorded. Total chloride transport was computed for each nostril. The total chloride transport values were calculated by subtracting the voltages at the end of a perfusion from the voltage at the end of an earlier perfusion (isoproterenol - amiloride). The average of the values for each nostril was computed. If the assessment was available in only 1 nostril, this value was used as if it were the average of both nostrils. Normalization of chloride transport (normal range \[NR\]) was defined as nasal TEPD that was at least as electrically negative as -5 mV. Normalization in chloride transport can also be referred to as hyperpolarization.

The objective of this study is to determine the effects of rifampin on the pharmacokinetics of ataluren under fasting conditions.

The objective of this study is to determine the effects of rifampin on the pharmacokinetics of ataluren under fasting conditions.