This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Evaluation of Ivacaftor in Patients Using Ataluren for Nonsense Mutations (NCT03256799), a na phase 4 study. The primary outcome is Lung Function.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03256799 |
| Phase | Phase 4 |
| Condition | Cystic Fibrosis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Alabama at Birmingham |
| Results posted | Yes |
2. Clinical Question
Population
Patients with cystic fibrosis using ataluren for nonsense mutations were the intended population. The registry record lists cystic fibrosis as the condition and states that the study explored the combination in patients with a specific cystic fibrosis mutation. It does not report further eligibility details or describe the characteristics of the enrolled participant.
Intervention
The intervention was ivacaftor/ataluren. The study is described as open label, so masking was none. The registry record does not provide further dosing or treatment-administration details in the arm description.
Comparator
No separate comparison group is recorded. The study is classified as single group, and allocation is listed as not applicable. It therefore does not provide a randomized, like-for-like control comparison against another treatment or against no study treatment.
Primary question
The primary outcome was lung function, measured by spirometry, with change described from baseline through 48 weeks and the unit listed as liters. The clinical question was whether lung function changed during this treatment combination. The registry record does not report a numerical change or an analysis result, so the direction and precision of any observed change cannot be assessed.
3. Trial Design
This was a Phase 4, open-label, single-group study sponsored by the University of Alabama at Birmingham. The registry lists the study as completed, with a start date of 2017-03-17 and primary completion on 2017-07-10. Enrollment was 1. The intervention was ivacaftor/ataluren, and the study description identifies patients using ataluren for cystic fibrosis nonsense mutations as the group of interest.
Allocation is listed as not applicable and masking as none. There is no separate control arm recorded, so the design does not support a randomized between-group treatment comparison. Observations over time in a single group can describe changes during the study, but those changes cannot by themselves distinguish treatment effects from other influences, such as natural variation or changes in participants’ circumstances.
The primary outcome is described as change in lung function measured by spirometry, from baseline through 48 weeks. The registry record lists one outcome measure and no analysis entries. It does not report the outcome value, the analysis method, or a more detailed description of the enrolled population. The arm description is blank, so treatment details beyond the intervention name are not reported in the registry record.
The study’s completed status indicates the registry’s status classification, but it does not supply the missing outcome analysis. The recorded enrollment is also important context for interpreting the evidence: the registry describes a very limited amount of participant-level information, and no comparative group is available to provide a concurrent reference.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: there was no multiple arms in this study and no multiple groups
Overall Study
| Stage | Ivacaftor/Ataluren |
|---|---|
| STARTED | 1 |
| COMPLETED | 1 |
| NOT COMPLETED | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Ivacaftor/Ataluren |
|---|---|---|
| Participants analysed | 1 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: caucasian, non-hispanic | Participants | 1 |
| Region of Enrollment: United States | participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Lung Function, measured over Baseline through 48 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Liters |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Lung Function.” It is described as change in lung function measured by spirometry, with liters as the unit and a timeframe from baseline through 48 weeks. Spirometry is used to quantify aspects of respiratory function; measuring change allows investigators to describe how the recorded value differs over the stated observation period.
As a general statistical point, a change endpoint summarizes the difference between a participant’s measurement at a later assessment and a baseline measurement. The summary can describe direction and magnitude, but its interpretation depends on how measurements were collected, how missing observations were handled, and how results were aggregated. Those details are not reported in the registry record.
The endpoint is clinically relevant to a study focused on cystic fibrosis and lung function, but the registry record does not provide its numerical result, variability, confidence interval, or statistical test. The outcome therefore cannot be interpreted for direction, size, or precision from the registry information. The stated timeframe identifies the intended period of assessment; it does not establish that complete measurements were available at every assessment.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record defines a lung-function outcome measured by spirometry and describes change from baseline through 48 weeks. It does not report the numerical outcome result or an analysis. Consequently, the posted record does not establish whether the recorded lung-function value increased, decreased, or remained similar over the stated period. It also does not provide an estimate of the size or precision of any change.
The study is single group, open label, and has no separate comparator. Even if a within-group change estimate were available, it would describe change among the observed participants during follow-up; it would not, on its own, isolate the effect of the combination. Without a concurrent control group, changes could also reflect natural fluctuation, measurement variation, time trends, or other factors. This is a design limitation, not a conclusion that any particular alternative explanation occurred.
Enrollment was 1, and the registry lists no analysis entries. That makes the lack of a reported outcome especially consequential: there is no posted estimate from which to assess the observed pattern, and no reported uncertainty measure to show how precisely it was estimated. A confidence interval, when reported, describes a range of values compatible with the data and analysis under its assumptions. No such interval is reported in the registry record.
The recorded adverse-event counts offer limited safety information but do not fill the gap in efficacy reporting. The registry lists 1 participant at risk for serious adverse events, 0 affected, and 1 at risk for other adverse events, 1 affected. Deaths are listed as 0. These counts describe the recorded event categories during the study; they do not provide a comparative safety estimate.
Overall, the registry record documents the question and design, but not an interpretable numerical result for the primary endpoint. This means the posted information cannot support a statistical judgment about the direction, magnitude, or precision of lung-function change. It also cannot establish a causal treatment effect or compare the combination with an alternative.
9. Statistical Methods Explained
The registry classifies this study as single group, with allocation not applicable and masking none. These design features determine what kinds of statistical conclusions are available. A single-group study can describe measurements within its enrolled group, including changes over time if those measurements and their analysis are reported. It does not create a randomized contrast between treatment groups. Open-label status means the record does not describe masked treatment assignment or assessment.
As a general statistical point, random allocation helps make groups comparable, on average, with respect to measured and unmeasured factors. A concurrent control group also helps distinguish treatment-period changes from changes that might have happened without the intervention. Neither feature is recorded for this study. Any within-group change, if reported, would therefore be descriptive of the observed course and would not alone demonstrate that the intervention caused it.
The primary measure is change in spirometry-measured lung function, with liters as the unit and a timeframe from baseline through 48 weeks. A change measure requires a baseline value and a later value, together with a rule for summarizing those observations. General considerations include which assessment times contribute, whether all enrolled participants are included, and how unavailable measurements are treated. These analysis details are not reported in the registry record, and no numerical outcome analysis is listed.
Uncertainty is ordinarily conveyed with a standard error, confidence interval, or test result. As a general explanation, a confidence interval communicates the precision of an estimate under the statistical model and assumptions used. It does not eliminate limitations in the design, and it cannot be interpreted without knowing what estimate and analysis produced it. The registry record reports no outcome estimate, interval, or test, so these features cannot be evaluated for lung-function change.
The record lists enrollment as 1 and reports no analysis entries. Enrollment describes the recorded study size; it should not be mistaken for evidence that the primary endpoint was analyzed or that an analysis result is available. The participant population, analysis population, and handling of any missing endpoint data are not reported in the registry record.
The record also includes a planning illustration framework based on fractions of an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such planning calculations are hypothetical design illustrations, not observed power and not evidence of a treatment effect. They do not describe the original study’s design justification, which is not reported in the registry record. The study itself is single group, so the equal-allocation, two-arm assumption in the planning framework is not a description of its actual design. No numerical planning result is stated in the registry record.
As a general statistical point, power calculations depend on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. A planning illustration can show how changing an assumed effect relates to a hypothetical study size, but it cannot establish that a completed study was adequately powered. In particular, calculations based on an observed effect may be unstable when the underlying estimate is based on very limited data. They should not be read as an outcome analysis or as a substitute for a reported confidence interval.
Over-dispersion is a general issue when observed count variation exceeds what a chosen statistical model expects. A model that fails to account for it may understate uncertainty. That concept is not a reported analysis feature of this trial: the primary endpoint is a spirometry-based change measure, and the registry does not describe a model, dispersion estimate, or inferential method. No assumptions about such methods can be made from the endpoint label alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and no analysis entries. It does not report a statistical analysis plan, a hierarchy of outcomes, or a procedure for addressing multiplicity. Multiplicity arises when several outcomes, time points, or statistical comparisons are assessed; repeated testing can increase the chance of a seemingly notable result arising by chance. That general concern cannot be quantified for this study from the registry record, which does not describe the analysis choices or report tests.
The primary endpoint is identified as lung-function change from baseline through 48 weeks, but the record does not provide details about which spirometry assessments were analyzed or how the change was summarized. It also does not report the analysis population, exclusions from analysis, or the approach to missing measurements. Those details matter because different inclusion and missing-data rules can yield different estimates and uncertainty.
As a general statistical point, missing-data methods rely on assumptions about why measurements are unavailable and how missingness relates to observed or unobserved outcomes. A method cannot be judged from the outcome label or timeframe alone. The registry record does not report reasons for missingness or a method for handling it. It therefore does not support conclusions about whether missing data affected the endpoint estimate.
No interim analysis information is reported in the registry record. The statistical plan, including any prespecified hypothesis tests or multiplicity adjustments, is also not reported in the registry record. In the absence of these details and outcome analyses, there is no basis for evaluating whether the posted analyses followed a prespecified approach or whether selective reporting is a concern in this record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Ivacaftor/Ataluren | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Ivacaftor/Ataluren | 0 of 1 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ivacaftor/Ataluren | 1 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ivacaftor/Ataluren |
|---|---|---|
| pulmonary exacerbation | Respiratory, thoracic and mediastinal disorders | 1 of 1 |
The registry reports 1 participant at risk for serious adverse events, with 0 affected. For other adverse events, it reports 1 at risk and 1 affected. Deaths are listed as 0. These are recorded counts for the ivacaftor/ataluren group; they are not comparative rates and should not be interpreted as a comparison with an untreated or alternative-treatment group.
As a general point, serious and other adverse-event categories are distinct reporting classifications, and the counts do not by themselves describe event severity beyond those categories, timing, duration, or attribution. The record does not list serious adverse-event terms. It does not provide further detail about the other event, its relationship to treatment, or whether the event count represents a particular type of event. Those details are not reported in the registry record.
The small amount of recorded safety information limits what can be inferred about the range or frequency of adverse events. A count of 0 serious events in the recorded group does not establish that serious events cannot occur, and the other-event count does not provide a comparative estimate. The registry figures are descriptive of the information recorded for this study, not proof of safety or harm.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed, open-label, single-group Phase 4 study evaluated ivacaftor with ataluren in patients with cystic fibrosis using ataluren for nonsense mutations. It identifies spirometry-measured lung-function change from baseline through 48 weeks as the primary outcome. These details clarify the study’s question and the kind of measurement intended.
The record does not report the numerical primary outcome or any analysis entries. It therefore does not show the direction, size, or precision of lung-function change. Without an estimate and an uncertainty measure, readers cannot assess how much variation might be compatible with the observed data. Nor can they judge whether a change is distinguishable from measurement variability or other sources of change.
The single-group design also limits causal interpretation. A change over time, if available, would not by itself show that the combination caused that change. A concurrent comparison group is not recorded, and no randomized comparison is available. The study record therefore cannot provide a treatment contrast against another approach.
The adverse-event counts describe the registry’s recorded safety categories for the group, but they do not provide comparative safety evidence or detailed event descriptions. Likewise, completed status does not supply the missing analysis. The record’s enrollment and design are relevant context, but neither substitutes for reported outcome results.
In short, this registry record documents a clinical question, an intervention, and an endpoint, while leaving the primary statistical result unavailable. It does not establish that the combination improved or worsened lung function, and it does not establish equivalence or absence of an effect. Those conclusions require outcome data and analysis that are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of the distinction between a clearly stated research question and an interpretable result. The registry identifies a treatment combination, a population of interest, and a spirometry-based endpoint. However, it does not report a numerical endpoint result or an analysis. Without those, readers cannot assess effect direction, magnitude, or precision.
Its single-group, open-label design also illustrates why study structure matters when interpreting change over time. A before-and-after measurement can describe what happened in the observed group, but it does not supply a concurrent counterfactual: what would have happened over the same period without the intervention. The absence of a control comparison limits causal interpretation regardless of the statistical method used to summarize change.
The registry lists enrollment as 1. This is important context for the amount of participant information represented, but it does not itself explain the study’s rationale or whether the original design was intended for a particular purpose. That justification is not reported in the registry record. The planning framework should also be distinguished from the actual design: its assumptions include equal allocation between two arms, whereas the recorded study is single group.
The case also shows why safety counts need context. Recorded counts can describe events within the study, but without a comparator they cannot estimate relative risk. In combination with missing endpoint analyses, they leave substantial uncertainty about what can be concluded from the registry record. The main statistical lesson is to separate design information, planning assumptions, and observed analysis results rather than treating them as interchangeable.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The central limitation is that the registry record does not report the numerical result or analysis for the primary lung-function endpoint. Without those results, there is no posted estimate or uncertainty measure to interpret. The endpoint timeframe is stated as baseline through 48 weeks, but the record does not report which observations were available or how the change was calculated.
The study is single group, open label, and has no separate comparator. Consequently, it cannot provide a randomized between-group estimate, and any within-group change would have limited causal interpretability. Masking is listed as none, and no information is reported about blinding of outcome assessment.
Enrollment is 1, so the recorded study contains limited participant-level information. The registry record does not report participant characteristics, further eligibility details, or the analysis population. It also does not report missing-data handling, the statistical analysis plan, multiplicity procedures, or interim analyses. These omissions prevent evaluation of analysis choices and their implications.
The arm description does not give further treatment details beyond the intervention name. The registry does not list serious adverse-event terms or provide detail about the recorded other adverse event. The event counts therefore have limited interpretability and cannot be compared with another group.
Finally, planning assumptions in the sample-size framework are not the same as the study’s actual design or its results. The framework’s two-arm equal-allocation assumption does not describe the recorded single-group study. The original sample-size justification is not reported in the registry record. These limitations concern what can be concluded from the registry information; they do not establish what may have been measured or analyzed outside that record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation of Ivacaftor in Patients Using Ataluren for Nonsense Mutations — NCT03256799.
- Registry record last updated 2019-07-19; status last verified 2019-06.
- Results first posted 2019-07-19.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record identifies NCT03256799 as a completed Phase 4, open-label, single-group study sponsored by the University of Alabama at Birmingham. It evaluated ivacaftor/ataluren in patients with cystic fibrosis using ataluren for nonsense mutations. Enrollment was 1; the listed start date is 2017-03-17 and primary completion is 2017-07-10.
The primary outcome was lung-function change measured by spirometry, in liters, from baseline through 48 weeks. The registry lists no analysis entries and does not report a numerical result for this outcome. Serious adverse events were recorded for 0 of 1 at risk; other adverse events for 1 of 1 at risk; deaths were 0. No comparator is recorded, so the study does not provide a randomized treatment comparison.