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 A Study of Dexlansoprazole Modified Release Formulation to Treat Night Heartburn (NCT00627016), a randomized phase 3 study. The primary outcome is Median Percentage of Nights Without Heartburn Over 4 Weeks as Assessed by Daily Diary..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00627016 |
| Phase | Phase 3 |
| Condition | Gastroesophageal Reflux |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 305 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Takeda |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerned subjects with symptomatic gastroesophageal reflux disease and nocturnal heartburn. The primary analysis included randomized subjects who received at least one dose of study drug and completed at least one diary entry for nighttime heartburn during treatment. The registry record does not report further eligibility details in the posted results.
Intervention
The intervention was dexlansoprazole 30 mg once daily. Participants recorded the presence or absence of nighttime heartburn in a daily electronic diary. The primary endpoint summarized diary results over 4 weeks.
Comparator
The comparator was placebo. The trial was randomized and parallel group, with placebo control. The registry describes masking as triple; the official title calls the trial double-blind. Which individuals were masked is not reported in the registry record.
Primary question
The main question was whether the distribution of the percentage of nights without heartburn over 4 weeks differed between the dexlansoprazole and placebo groups. The posted medians were 73.1% with dexlansoprazole and 35.7% with placebo. A Wilcoxon (Mann-Whitney) analysis reported p < 0.001. This is evidence of a difference in the groups’ diary-based outcomes under the reported analysis; it does not by itself establish how the result applies beyond the analyzed participants or address the importance of the difference to any individual.
3. Trial Design
This was a Phase 3, multicenter, randomized, parallel-group, placebo-controlled trial of dexlansoprazole for nocturnal heartburn in subjects with symptomatic gastroesophageal reflux disease. The official title describes a double-blind design, while the registry’s masking entry says triple. The record does not identify the masked roles or explain the difference in those descriptions. The trial compared dexlansoprazole 30 mg once daily with placebo.
The registry reports enrollment of 305 and a completed study. The recorded start was 2008-03 and primary completion was 2009-03. These dates describe the registry record and do not establish the length of treatment for each participant. The primary outcome timeframe was 4 weeks.
For the primary analysis, the stated population consisted of randomized subjects who received at least one dose of study drug and had at least one diary entry for nighttime heartburn during treatment. The primary arm counts were 153 for placebo and 151 for dexlansoprazole. The registry record does not report the detailed randomization procedure, allocation concealment, treatment adherence, or participant flow through the study.
The posted primary comparison used a Wilcoxon (Mann-Whitney) test. The secondary diary outcomes were assessed over the last 7 days of treatment, and their reported comparisons used Fisher exact tests. The registry record does not report a full statistical analysis plan, a sample-size justification, or interim analyses. Those omissions mean the posted results do not establish which other analyses or design decisions were planned in advance.
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: Subjects eligible for entry into the Treatment Period were randomized into one of two, once-daily (QD) treatment groups.
Overall Study
| Stage | Placebo | Dexlansoprazole 30 mg QD |
|---|---|---|
| STARTED | 153 | 152 |
| COMPLETED | 147 | 146 |
| NOT COMPLETED | 6 | 6 |
Reasons for not completing this period:
| Reason | Placebo | Dexlansoprazole 30 mg QD |
|---|---|---|
| Adverse Event | 1 | 1 |
| Protocol Violation | 0 | 2 |
| Lost to Follow-up | 0 | 1 |
| Withdrawal by Subject | 2 | 1 |
| Failed Inclusion/Exclusion Criteria | 0 | 1 |
| Lack of Efficacy | 1 | 0 |
| Placed on Excluded Drugs | 1 | 0 |
| Pregnancy | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Analysis was conducted on intent-to-treat subjects (randomized subjects who received at least 1 dose of study drug) who completed at least 1 diary entry for nighttime heartburn during treatment.
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 | Placebo | Dexlansoprazole 30 mg QD | Total |
|---|---|---|---|---|
| Participants analysed | 153 | 152 | 305 | |
| Age, Customized: <45 years | participants | 75 | 75 | 150 |
| Age, Customized: 45 to <65 years | participants | 76 | 75 | 151 |
| Age, Customized: >=65 years | participants | 2 | 2 | 4 |
| Age Continuous | years | 43.9 (SD 12.45) | 44.6 (SD 11.29) | 44.2 (SD 11.87) |
| Sex: Female, Male: Female | Participants | 98 | 97 | 195 |
| Sex: Female, Male: Male | Participants | 55 | 55 | 110 |
| Region of Enrollment: United States | participants | 153 | 152 | 305 |
| Number of Days with Night Heartburn: 0-3 days | participants | 10 | 3 | 13 |
| Number of Days with Night Heartburn: 4-5 days | participants | 36 | 38 | 74 |
| Number of Days with Night Heartburn: 6-7 days | participants | 107 | 111 | 218 |
| Number of Nights with Sleep Disturbances Related to Gastroesophageal Reflux Disease (GERD) Symptoms: 0-3 Nights | participants | 40 | 33 | 73 |
| Number of Nights with Sleep Disturbances Related to Gastroesophageal Reflux Disease (GERD) Symptoms: 4-5 Nights | participants | 53 | 47 | 100 |
| Number of Nights with Sleep Disturbances Related to Gastroesophageal Reflux Disease (GERD) Symptoms: 6-7 Nights | participants | 60 | 72 | 132 |
6. Primary Endpoint
The registry lists the primary outcome as Median Percentage of Nights Without Heartburn Over 4 Weeks as Assessed by Daily Diary., measured over 4 Weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | Percentage of nights |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the median percentage of nights without heartburn over 4 weeks, assessed by daily diary. For each participant, the percentage was based on nights with a diary entry indicating whether nighttime heartburn was present or absent. Nights missing diary results were excluded from both the numerator and denominator. Participants needed at least one such diary entry to enter the primary analysis population.
This endpoint expresses the share of observed diary nights that were free of reported heartburn. It uses repeated nightly reports over the treatment period rather than relying on a single end-of-study recollection. The median describes the middle of the participant-level percentages in each group. The interquartile range gives the spread of the middle half of those percentages; it is not a confidence interval for the median and does not directly describe the uncertainty in the treatment contrast.
The endpoint is relevant to the trial’s stated question because it focuses on nighttime heartburn across the treatment period. However, diary-based measurement depends on entries being completed, and the analysis excludes nights without diary results from the calculation. The registry does not report a sensitivity analysis showing how alternative handling of missing diary entries would affect the result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome medians were 35.7% of nights without heartburn for placebo and 73.1% for dexlansoprazole 30 mg once daily. The interquartile ranges were 30.0 and 35.0, respectively. These are summaries of the participant-level percentages, not means, and the interquartile ranges describe variability among participants rather than precision of the estimated group contrast. The registry reports a Wilcoxon (Mann-Whitney) comparison with p < 0.001.
The reported test assesses whether the two groups’ outcome distributions differ, using ranks rather than relying on a comparison of means under a normal-distribution model. The small p-value indicates that the observed rank separation would be unusual under the test’s null model of no distributional difference. It does not give the probability that the null hypothesis is true, nor does it quantify the size or clinical importance of the difference. The registry does not provide a treatment-contrast estimate or confidence interval for the primary outcome.
The posted secondary outcomes also have lower reported percentages in the placebo group than in the dexlansoprazole group for relief of nighttime heartburn and relief of GERD-associated sleep disturbances during the last 7 days of treatment. Their reported Fisher exact tests each have p < 0.001. These endpoints concern different diary-based definitions and time windows, and should not be treated as interchangeable with the primary measure.
Two-arm recalculations for the binary secondary outcomes give unadjusted estimates and confidence intervals, but they do not replace the sponsor’s reported analyses. The secondary results are not adjusted for multiplicity in the posted results, and the registry record does not report whether an adjustment was prespecified. Accordingly, they offer supporting descriptive evidence of a consistent pattern, but they warrant more caution than a prespecified primary endpoint interpreted under a documented analysis plan.
These results describe the posted trial outcomes and analyses. The record does not provide enough information to assess all possible sources of bias, the robustness of the findings to missing diary data, or the applicability of the results to people outside the analyzed population.
9. Statistical Methods Explained
The primary endpoint is a participant-level percentage, and the registry summarizes each group with a median and interquartile range. A median is the center of the ordered observations: half the observed values fall at or below it and half at or above it, subject to ties. The interquartile range describes the spread between the central quartiles. These summaries are useful when outcomes may be skewed or contain extreme values, because they are less driven by extreme observations than a mean and standard deviation would be. They do not, on their own, show the uncertainty in the difference between groups.
What does the Wilcoxon (Mann-Whitney) test assess?
The reported primary test is a rank-based comparison of the two groups. It orders participant outcomes and uses those ranks to assess whether one group tends to have higher or lower observations than the other. This avoids requiring the outcome to follow a normal distribution. The test is commonly interpreted as a comparison of distributions; a simple interpretation as a shift in medians needs additional assumptions about the shape of those distributions. The registry does not report a primary treatment-effect estimate or confidence interval, so the test result does not convey a precise estimate of the magnitude of the contrast.
The reported p-value is p < 0.001. A p-value measures how incompatible the observed test result is with the test’s null model, assuming the model and analysis are appropriate. It is not the probability that the treatment has no effect, and it does not measure the chance that the result will replicate. A small p-value also does not determine whether a difference is clinically important.
How are binary outcomes compared?
The secondary outcomes classify participants according to whether they had the specified relief during the last 7 days of treatment. The sponsor’s reported method was Fisher exact testing. This test evaluates the association between group assignment and a binary outcome and is useful when the data are represented as counts of participants with and without the outcome. The registry reports p < 0.001 for each of these comparisons.
Unadjusted recalculations from the posted counts express the difference as a risk difference and provide a confidence interval. A risk difference compares the event proportions directly, while a confidence interval describes the range of values reasonably compatible with the observed data under the calculation’s assumptions. These are simple, unadjusted recalculations; they are not an adjusted model or a substitute for the sponsor’s analysis. They do not account for multiplicity across outcomes. The primary outcome is not accompanied by such a recalculated contrast in the posted results.
What does the planning illustration represent?
Planning illustrations for the binary secondary outcomes use the observed effect, or a stated fraction of it, to estimate participants per arm for 80% power and participants per arm for 90% power. The stated assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation. For the nighttime-heartburn relief outcome, the illustrations range from 44 participants per arm for 80% power at 100% of the observed effect to 156 participants per arm at 50% of the observed effect. For GERD-associated sleep-disturbance relief, the corresponding illustrations range from 79 to 328 participants per arm for 80% power. The 90% planning values are also reported for each stated effect fraction.
These figures are planning illustrations derived from observed outcomes, not the trial’s original sample-size justification and not observed power. Power is a design concept tied to assumed effects and analysis conditions; calculating it from an observed effect does not establish the probability that the trial’s result is true. The registry record does not report the trial’s own sample-size assumptions or justification.
What is not established by the posted methods?
The registry record does not report a complete statistical analysis plan, the handling of all missing data beyond the primary endpoint’s stated diary calculation, or whether analyses were prespecified. It also does not report interim analyses. Without those details, readers cannot determine whether all planned outcomes and analyses are represented, whether the reported tests were chosen before the results were known, or how sensitive the conclusions are to alternative reasonable analysis choices.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Wilcoxon (Mann-Whitney) | not reported | < 0.001 |
The sponsor-reported primary analysis used a Wilcoxon (Mann-Whitney) test and reported p < 0.001. No sponsor-reported primary contrast estimate or confidence interval appears in the registry record. The posted primary summaries give medians of 35.7% for placebo and 73.1% for dexlansoprazole, with interquartile ranges of 30.0 and 35.0. The rank-based result and the group summaries point to a difference in the observed distributions, but the posted information does not quantify the primary contrast with an interval estimate.
For both binary secondary outcomes, the sponsor-reported method was Fisher exact testing and the reported p-value was p < 0.001. Simple unadjusted recalculations from the posted summary counts provide risk-difference estimates and confidence intervals. Those calculations are not the sponsor’s reported model or analysis, and they do not account for multiplicity. Their role is to express the observed binary contrasts in an additional way, not to override the reported analysis.
The registry record indicates no discrepancy between the posted sponsor results and the recalculations. The recalculations are therefore supplementary; the sponsor’s reported analyses remain the primary inferential results to cite. The registry record does not report additional details that would allow a broader reconciliation with a full protocol or statistical analysis plan.
11. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when several outcomes or comparisons are tested. If each is judged separately without an adjustment or prespecified testing strategy, the overall chance of a false-positive result can be higher than the nominal error rate for an individual test. That concern is relevant because the registry reports a primary outcome and two secondary outcomes, each with a group comparison. The secondary p-values are reported as p < 0.001, but the registry record does not report whether multiplicity was addressed, whether outcomes were tested in a hierarchy, or whether any other comparisons were planned.
The primary endpoint calculation excludes nights without diary results from its numerator and denominator. The stated primary analysis population also requires at least one nighttime-heartburn diary entry during treatment. These rules define how available diary observations contribute to the endpoint, but they do not show how much data were missing or whether missingness differed by group. The registry record does not report a sensitivity analysis using alternative missing-data assumptions. The record also does not report detailed missing-data handling for the secondary outcomes.
The primary analysis population is described as randomized subjects who received at least one dose of study drug and had at least one qualifying diary entry. This is not a description of every randomized participant regardless of treatment received or diary completion. The registry record does not report a full participant-flow account or enough information to determine how exclusions and missing entries affected the analyses. The posted secondary arm counts differ from one another and from the primary analysis counts, but the registry record does not explain the reasons for those denominators.
These gaps matter because diary completion and analysis-population definitions can affect the observed outcomes. They do not show that the results are biased, but they prevent readers from judging the sensitivity of the findings to missing information, exclusions, or multiple testing. The registry record does not report interim analyses or a full statistical analysis plan that could clarify these choices.
12. 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 |
|---|---|---|---|
| Placebo | 1 | 153 | 0.7% |
| Dexlansoprazole 30 mg QD | 0 | 152 | 0.0% |
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 |
|---|---|
| Placebo | 3 of 153 |
| Dexlansoprazole 30 mg QD | 7 of 152 |
Most frequent serious adverse event terms
| Event term | Organ system | Placebo | Dexlansoprazole 30 mg QD |
|---|---|---|---|
| Abortions Spontaneous | Pregnancy, puerperium and perinatal conditions | 1 of 153 | 0 of 152 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Placebo | Dexlansoprazole 30 mg QD |
|---|---|---|---|
| Upper Respiratory Tract Infections | Infections and infestations | 3 of 153 | 7 of 152 |
Serious events with the highest arm-level rate: abortions spontaneous (0.7%).
The registry reports serious adverse events affecting 1 of 153 participants in the placebo group and 0 of 152 in the dexlansoprazole group. Other adverse events affected 3 of 153 participants in the placebo group and 7 of 152 in the dexlansoprazole group. These are counts among the listed groups, not estimates of comparative risk adjusted for exposure or other factors. The registry record does not report deaths.
The posted serious-event listing names “Abortions Spontaneous” at 0.7% as a top serious term. The registry record does not identify the treatment group for that term in the information, so it should not be assigned to either group. A term listing alone does not establish causation or provide context about the event.
These figures should be read as descriptive safety counts, not as a definitive comparison. The record does not provide enough detail about event definitions, timing, severity beyond the serious-event classification, treatment exposure, or assessment of relatedness to support a broader safety conclusion. Differences in counts do not establish that treatment caused or prevented an event.
13. What the Result Does, and Does Not, Mean
The primary result shows that the group assigned to dexlansoprazole had a higher median percentage of nights without heartburn than the placebo group over the reported 4-week period. The Wilcoxon (Mann-Whitney) test reported p < 0.001. The posted secondary outcomes also point in the same direction for diary-reported relief measures during the last 7 days of treatment. Together, these findings describe a group-level pattern in the trial’s recorded outcomes.
The result does not state that every participant experienced the same outcome, or that any particular participant would have had the same result. Group medians and percentages summarize observations across participants; they do not predict an individual response. Nor does a small p-value establish that the observed difference is clinically important. The registry record does not report a primary treatment-contrast estimate with a confidence interval that would quantify the uncertainty and scale of that contrast.
The endpoint depends on diary reports and on having at least one qualifying diary entry. Missing diary nights were excluded from the primary calculation. Without detailed missingness information or sensitivity analyses, the effect of incomplete diary data cannot be assessed from the registry record. The secondary analyses are also unadjusted in the posted results, and the record does not report how multiplicity was handled.
These results should therefore be understood within the trial’s population, treatment period, endpoint definitions, and available analyses. The registry record does not establish how well the findings apply to other populations or settings, and it does not supply the protocol and analysis-plan details needed to evaluate every design and analysis choice. The statistical evidence describes the posted trial data; it is not medical advice or a guarantee of an outcome for an individual.
14. Why This Trial Matters Statistically
This trial illustrates why the choice of endpoint summary and test matters. The primary outcome is a participant-level percentage derived from repeated nightly diary entries, then summarized by medians and interquartile ranges. A rank-based test was used rather than a comparison of means. That approach fits a setting where the outcome is a bounded percentage and where the distribution need not be adequately described by a normal model, while still leaving the reader without a direct estimate and confidence interval for the primary contrast.
The endpoint also makes diary completeness part of the statistical interpretation. Missing nights were excluded from the individual calculation, and entry into the analysis required at least one qualifying diary entry. Those rules are clearly relevant to what the percentage represents. Without detailed information about missingness or sensitivity analyses, readers cannot tell whether alternative assumptions about unobserved nights would change the result.
The two secondary outcomes provide a useful example of distinct analyses answering related, but not identical, questions. They use binary relief measures over the last 7 days and Fisher exact tests, whereas the primary outcome summarizes the percentage of nights without heartburn over 4 weeks. Agreement in direction across endpoints is informative, but unadjusted secondary tests do not have the same inferential standing as a primary endpoint within a documented testing plan.
Finally, the registry offers a setting to distinguish reported inference from recalculation. Simple unadjusted estimates can help express binary group contrasts, but they cannot recover unreported design choices or replace the sponsor’s analysis. The record’s missing details about multiplicity, sample-size justification, and analysis planning are statistically important because they limit assessment of prespecification and robustness.
15. 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 registry record does not report a primary contrast estimate or confidence interval. The medians and interquartile ranges describe the groups, but do not quantify the uncertainty around their difference. As a result, the strength of the primary comparison is expressed through a p-value rather than an interval estimate for the treatment contrast.
Diary-based outcomes are subject to incomplete reporting. The primary endpoint excludes nights without diary results and requires at least one qualifying entry for inclusion in the analysis. The registry record does not report the amount or pattern of missing diary information, reasons for missingness, or sensitivity analyses. It also does not explain the differing analysis counts across endpoints.
The registry record does not report whether multiplicity was addressed, whether the secondary outcomes were tested in a hierarchy, or whether the posted analyses were fully prespecified. It also does not report a full statistical analysis plan, the original sample-size justification, or interim analyses. These absences limit assessment of the design assumptions and the robustness of the inferences.
The study description contains different masking labels: the official title says double-blind, while the registry entry says triple. The registry record does not identify who was masked or explain the labels. It also does not report detailed randomization or allocation-concealment procedures, participant flow, adherence, or further population characteristics in the posted results. These details could inform assessment of bias and generalizability, but cannot be inferred from the reported outcomes.
Finally, the safety figures are descriptive counts. The registry record does not provide enough event-level detail, exposure information, or relatedness assessment to support a comprehensive comparative safety interpretation.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: A Study of Dexlansoprazole Modified Release Formulation to Treat Night Heartburn — NCT00627016.
- Registry record last updated 2011-04-28; status last verified 2011-04.
- Results first posted 2010-05-06.
- 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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19. Record Summary
NCT00627016 is a completed Phase 3, multicenter, randomized, parallel-group, placebo-controlled study of dexlansoprazole 30 mg once daily for nocturnal heartburn in subjects with symptomatic gastroesophageal reflux disease. The primary endpoint was the median percentage of nights without heartburn over 4 weeks, assessed by daily diary. The posted medians were 73.1% for dexlansoprazole and 35.7% for placebo, with a Wilcoxon (Mann-Whitney) p-value of p < 0.001.
Two secondary diary outcomes assessed relief during the last 7 days of treatment; each reported Fisher exact comparison had p < 0.001. The record also includes descriptive adverse-event counts. Important details about multiplicity, missing-data sensitivity, the original sample-size justification, and the full statistical analysis plan are not reported in the registry record.