A Study of Ataluren in Pediatric Participants With Cystic Fibrosis

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.

To assess TEPD, warmed solutions of Ringer's solution, amiloride, chloride-free gluconate, isoproterenol and ATP were perfused for ≥3-minutes sequentially through a nasal catheter while a voltage tracing was recorded. Total chloride transport was computed per nostril. Totals were calculated by subtracting voltages at end of perfusion from voltage at end of earlier perfusion for: sodium transport (amiloride-Ringer's solution), intrinsic chloride transport (chloride-free gluconate-amiloride), stimulated chloride transport (isoproterenol-chloride-free gluconate), total potential difference (isoproterenol-Ringer's solution), and ATP-mediated chloride transport (ATP-isoproterenol). Basal potential difference voltage was obtained at end of Ringer's solution perfusion. Average values per nostril were computed. If assessment was available in only 1 nostril, the value was used as if it's the average of both nostrils. Baseline data for Cycles 1 and 2 and change from Baseline data are presented.

The immunofluorescence staining of normal epithelial cells (for example, from nasal mucosal curettage) reveals the presence of cystic fibrosis transmembrane regulator (CFTR) protein at the apical surface. Cells were stained with antibodies that recognized an epitope in the C-terminal portion of the CFTR protein, and the cells were imaged microscopically. The percentage of epithelial cells that showed apical CFTR staining was determined by 2 expert readers who were blinded to the timepoint at which the samples were obtained. The scores of the reviewers were averaged to determine the final percentage of cells with apical CFTR. Overall Baseline data for the study and change from overall Baseline data at overall Day 56 are presented.

The collection and processing of the nasal mucosal curettage from each nostril of each participant for measurement of CFTR protein by immunofluorescence and for quantification of CFTR messenger ribonucleic acid (mRNA) was performed using standardized techniques. The slides were processed and immunostained for detection of CFTR protein. Microscopic images were to be captured photographically for analysis. Because the nasal brushing used to collect nasal mucosal epithelial cells did not result in collection of sufficient cells for RT-PCR to be performed, an insufficient number of paired baseline and follow-up samples were available for analysis. As a result, no data were available to evaluate the effects of ataluren on CFTR mRNA.

Pulmonary function tests, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and forced expiratory flow25-75 (FEF25-75), were measured using standard spirometry techniques. Overall Baseline data for the study and change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

The inflammatory marker free elastase was measured in induced sputum from each participant. Hypertonic saline (3%) inhalation was used to induce the sputum (with efforts made to avoid oropharyngeal contamination). The sputum sample was divided into 4 aliquots (1 aliquot each for determination of cell count, IL-8 level, and elastase activity and 1 aliquot for potential future viscosity measurements). Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

The inflammatory marker MMP-9 active was measured in induced sputum from each participant. Hypertonic saline (3%) inhalation was used to induce the sputum (with efforts made to avoid oropharyngeal contamination). The sputum sample was divided into 4 aliquots (1 aliquot each for determination of cell count, IL-8 level, and elastase activity and 1 aliquot for potential future viscosity measurements). Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

The inflammatory markers TNF-α, IL-8, and TGF-β1 were measured in induced sputum from each participant. Hypertonic saline (3%) inhalation was used to induce the sputum (with efforts made to avoid oropharyngeal contamination). The sputum sample was divided into 4 aliquots (1 aliquot each for determination of cell count, IL-8 level, and elastase activity and 1 aliquot for potential future viscosity measurements). Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

The inflammatory marker UTP was measured in induced sputum from each participant. Hypertonic saline (3%) inhalation was used to induce the sputum (with efforts made to avoid oropharyngeal contamination). The sputum sample was divided into 4 aliquots (1 aliquot each for determination of cell count, IL-8 level, and elastase activity and 1 aliquot for potential future viscosity measurements). Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

To assess inflammatory markers in the blood, neutrophil levels in the blood were measured. Higher levels of neutrophils are indicative of more inflammation. Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

To assess inflammatory markers in the blood, serum levels of C-reactive protein were measured. Higher levels of C-reactive protein are indicative of more inflammation. Change from overall Baseline data at Day 14 or 15 of Cycles 1 and 2 and at overall Day 56 are presented.

Body weight were measured for each participant in kilograms (kg). Overall Baseline data for the study and change from overall Baseline data at Day 14 of Cycles 1 and 2 and at overall Day 56 are presented.

The CF symptom questionnaire includes questions related to daytime cough, nighttime cough, sputum volume, sputum clearance, physical fatigue, and shortness of breath. The participants (or their guardians) completed the CF symptom questionnaire, under the Investigator's supervision, before the TEPD, nasal mucosal curettage, pulmonary function tests, or sputum induction procedures were performed. For each symptom, the participants were asked to choose the response that best matched their experience during the 3 days before the questionnaire was completed. The scale of the 4 possible responses for each question was 0 (best response) to 4 (worse response). The sum of the scores for all of the questions was calculated. The scale for the sum of the scores was 0 (best response) to 24 (worse response). Overall Baseline data for the study and change from overall Baseline data at Day 14 of Cycles 1 and 2 and at overall Day 56 are presented.

All PK parameters were calculated using the actual postdose blood sampling times in relationship to the time of the first dose (morning dose) on Day 14 of each treatment cycle. AUC0-24 values were calculated by WinNonlin by extrapolation to 24 hours if the last sampling timepoint was before 24 hours and by interpolation if the last sampling timepoint was after 24 hours. Extrapolation of AUC to 24 hours was performed only if the last sampling timepoint did not deviate from the nominal collection time by more than approximately 10%.

For each participant, compliance was described in terms of the percentage of drug actually taken relative to the amount that was prescribed (taking into account physician-prescribed reductions and interruptions). The number of doses described as "taken less than planned" includes cases in which the participants took less than the prescribed dose and/or cases in which the Investigator reduced the dose.