Randomized Trial of Glutamine in Patients With Mucositis or Esophagitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Randomized Trial of Glutamine in Patients With Mucositis or Esophagitis (NCT01952847), a randomized phase 3 study. The primary outcome is Severity of Esophagitis for Radiation Therapy Patients.

2. Clinical Question

3. Trial Design

This was a Phase 3, randomized, double-blind, placebo-controlled, parallel-group trial sponsored by M.D. Anderson Cancer Center. The registry lists enrollment of 77 and a status of terminated. The recorded start date is 2014-07-10, and the primary completion date is 2021-03-03. The reason for termination is not reported in the registry record; termination alone does not indicate why the trial stopped or what its results were.

The study addressed two clinical settings rather than a single interchangeable population. In one, participants were receiving an mTOR inhibitor-based regimen, with the study drink starting on the first day of anticancer therapy. In the other, participants were receiving radiation to the esophagus, with the drink starting on the first day of radiation. Each setting had glutamine and placebo groups. The registry record describes the drinks and their administration but does not report the dose of glutamine or the randomized allocation ratio.

The primary endpoint was specific to the radiation-to-esophagus group. It assessed the highest esophagitis grade observed by week six, and the stated primary analysis population was restricted to participants meeting the treatment-adherence threshold and protocol evaluability definition. Other listed outcomes address quality of life, esophagitis, mucositis, and durations of these conditions across the relevant treatment settings. The record lists 18 outcome measures and 11 analyses, but does not provide a complete account of how those analyses relate to each outcome.

Randomization can reduce systematic differences between treatment groups on average, while blinding can reduce some biases in treatment delivery and assessment. Those design features do not eliminate the possible effects of missing observations, limited enrollment, or an analysis population restricted by post-randomization adherence and evaluability. The registry record does not report the randomization procedure, any stratification factors, or the reason for termination.

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: The mTOR inhibitor cohort 24 patients consented. 10 enrolled patients became ineligible after consent and before randomization due to changes in their treatment plan. The radiation cohort enrolled 53 patients; 27 were randomized to the glutamine arm and 26 were randomized to the placebo arm.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who took at least 60% of the planned doses of the study treatment and were evaluable per protocol definition.

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.

Population: Data were unavailable for 1 participant who withdrew consent after randomization but before treatment start in mTOR Inhibitor Patient Group-Placebo

6. Primary Endpoint

The registry lists the primary outcome as Severity of Esophagitis for Radiation Therapy Patients, measured over 6 weeks.

The primary endpoint was the severity of esophagitis among participants receiving radiation to the esophagus. Severity was defined as the highest grade observed by week six. This captures the most severe recorded grade within the stated observation window, rather than describing how long esophagitis lasted or the full sequence of grades over time. The endpoint unit is participants, and the planned comparison uses the ordered categories of severity.

An ordered severity measure retains more information about the outcome than a simple event/no-event classification: participants can fall into categories that represent differing levels of severity. The Wilcoxon rank sum test is a rank-based method for comparing the distributions of such ordered observations between groups. In general, it uses the relative ordering of observations rather than requiring the categories to behave like equally spaced measurements. It tests for a distributional difference; by itself, it does not estimate a treatment effect in a directly interpretable clinical unit.

The registry record specifies the analysis population as participants who took at least 60% of planned study-treatment doses and were evaluable according to the protocol definition. The exact grading scale, grade-specific counts, group-level outcome summaries, test statistic, p-value, and confidence interval are not reported in the registry record. Consequently, the endpoint definition and planned test can be described, but the observed comparison cannot be interpreted from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the Wilcoxon rank sum test compare?

The Wilcoxon rank sum test is a nonparametric, rank-based method for comparing observations from two independent groups. In general, the observations are pooled and ordered, then their ranks are compared between groups. For an endpoint recorded in ordered categories, the ordering carries information even when the gaps between categories cannot be treated as equal numeric distances. The test evaluates whether the groups' observed distributions tend to differ in their ranks.

For this trial, the endpoint was each participant's highest esophagitis grade by week six, and the registry states that the test would compare ordered categories. The registry does not give the grade counts, ranks, test statistic, p-value, or an effect estimate. The test name alone does not reveal the direction or clinical size of a difference. Interpretation also depends on the observed data and on the analysis population actually used.

What does an ordered endpoint retain?

An ordered endpoint distinguishes levels of severity rather than reducing all observations to whether an event occurred. A rank-based comparison can use that ordering without assuming that the change from one category to the next has the same magnitude throughout the scale. This is useful when categories have a meaningful order but are not measurements on a continuous scale. However, a rank test does not directly provide the probability of an individual benefit, nor does it automatically provide a treatment effect in a familiar clinical unit. Those require estimates and summaries that are not reported in the registry record.

The endpoint is based on the highest grade during the observation window. As a general matter, a maximum can be affected by how often participants are assessed and whether observations are missing. The registry record does not describe assessment schedules in enough detail to evaluate those issues. Nor does it report how an unobserved grade or early withdrawal would be handled in the primary analysis.

How should a p-value and confidence interval be understood?

In general, a p-value measures how compatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. A confidence interval, in general, describes a range of effect estimates compatible with the data and method at the stated confidence level. Its width conveys precision: a wider interval indicates greater uncertainty. Neither a p-value nor a confidence interval for the primary comparison is reported in the registry record.

The Wilcoxon rank sum test is a test of a distributional contrast, and its result should be read alongside an appropriate effect estimate and uncertainty interval. It is not enough to know whether a threshold for statistical significance was crossed. The registry record does not provide the test output or the outcome summaries needed for a fuller interpretation.

What can sample-size illustrations tell readers?

Any sample-size figures associated with the posted results are planning illustrations, not the trial's original design justification. The stated illustration assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of an observed effect. For time-to-event outcomes, the illustration concerns total events; other illustrations are expressed as participants per arm. These assumptions describe hypothetical planning calculations and do not establish what the investigators planned, what effect they expected, or the probability that the completed trial would detect an effect.

General sample-size planning asks how much information a future study might need under particular assumptions. Changing the target effect or analysis assumptions changes the resulting planning requirement. Such illustrations are not observed power, and they cannot fill in missing primary outcome results. The original sample-size justification and statistical plan are not reported in the registry record.

General statistical practice also distinguishes the treatment effect estimate from the test used to assess evidence against a null hypothesis. The test may address whether a difference is detectable, while an estimate and interval help communicate its magnitude and precision. Since the registry record does not report primary outcome estimates or uncertainty, neither aspect of the primary comparison can be assessed from the record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 18 outcome measures and 11 analyses, including outcomes across two treatment settings and several domains: esophagitis, mucositis, quality of life, incidence, severity, and duration. When many outcomes or analyses are considered, the chance of at least one apparently notable result can increase. General approaches to multiplicity include identifying a primary outcome in advance, adjusting inferential thresholds, or interpreting secondary analyses as exploratory. The registry record does not report a multiplicity strategy, hierarchy among secondary outcomes, or which analyses were designated confirmatory beyond identifying the primary endpoint.

The primary analysis population is described as participants who took at least 60% of planned study-treatment doses and were evaluable according to the protocol definition. This is not the same as an analysis of everyone randomized. The exact number in that population, the detailed evaluability definition, and the number with observed primary endpoint data are not reported in the registry record. The record also does not explain whether participants were analyzed according to randomized assignment in other analyses.

Missing-data methods are not reported in the registry record. In general, missing outcomes can affect both precision and the validity of a comparison, particularly if missingness differs between groups or is related to outcome severity. The record does not say how missing grades, withdrawal, or incomplete follow-up were handled, or whether sensitivity analyses were conducted. The reason for trial termination and any effect of termination on follow-up or analysis are also not reported. These gaps prevent assessment of the robustness of the planned primary comparison and of the secondary analyses.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: diarrhea (16.7%), tumor pain (16.7%), nausea (14.3%), vomiting (14.3%), esophagitis (8.3%).

The registry reports serious and other adverse-event counts separately for each treatment group, with an at-risk count for each category. In the radiation-to-esophagus glutamine group, 25 were at risk for serious events and 5 were affected; 25 were at risk for other events and 20 were affected. In the corresponding placebo group, 24 were at risk for serious events and 3 were affected; 24 were at risk for other events and 15 were affected. In the mTOR inhibitor glutamine group, 7 were at risk for serious events and 1 was affected; 7 were at risk for other events and 5 were affected. In the mTOR inhibitor placebo group, 6 were at risk for serious events and 2 were affected; 6 were at risk for other events and 6 were affected.

The record also lists deaths by group: 6 in the radiation-to-esophagus glutamine group, 2 in its placebo group, and 0 in each mTOR inhibitor group. These figures do not establish that a death or adverse event was caused by study treatment. The registry record does not report attribution, event timing, exposure duration, or additional context needed for causal interpretation. Group counts should be read in their respective clinical settings rather than combined.

Listed serious-event terms include Diarrhea (16.7%), Tumor pain (16.7%), Nausea (14.3%), Vomiting (14.3%), Esophagitis (8.3%), and Dehydration (4.2%). The registry record does not explain whether participants could contribute more than one term or provide enough detail to interpret these percentages as comparative risks. These safety figures do not replace the missing primary outcome results.

12. What the Result Does, and Does Not, Mean

The registry record establishes that this was a randomized, double-blind, placebo-controlled Phase 3 study of glutamine in two treatment settings. It also specifies a primary endpoint for the radiation-to-esophagus group: the highest esophagitis grade observed by week six, compared using a Wilcoxon rank sum test in a defined per-protocol population. These details clarify the question the study was designed to address.

The record does not report the primary outcome comparison. Without group-level severity data or an effect estimate, it is not possible to say whether the observed severity was higher, lower, or similar between glutamine and placebo, or how precise any difference might be. The missing results do not establish either that glutamine was beneficial or that it was ineffective. They also do not establish that there was no difference.

The same caution applies to the listed secondary outcomes. Their names describe intended questions about quality of life, incidence, severe events, and duration, but outcome results are not reported in the registry record. A study's primary endpoint cannot stand in for those other outcomes, and findings in the radiation group would not automatically answer questions about the mTOR inhibitor group.

The safety counts provide descriptive information about recorded events and deaths by group. They do not by themselves show whether events were caused by the study treatment or permit a complete comparison of safety. Interpretation would require additional information about event definitions, timing, exposure, attribution, and uncertainty, which is not reported in the registry record.

The status of terminated is a registry status, not an outcome. Since the reason for termination is not reported, it cannot be interpreted as a signal about efficacy or safety. Overall, the record identifies the design and planned primary comparison but leaves the trial's primary result and several details needed to judge its reliability unreported.

13. Why This Trial Matters Statistically

This trial illustrates why endpoint definitions and analysis populations matter when reading clinical research. Its primary question is not simply whether esophagitis occurred. It concerns the highest recorded severity grade by week six, an ordered outcome, among radiation-to-esophagus participants who met stated adherence and evaluability conditions. That is a narrower question than the trial's broad aim of studying mouth or esophageal sores and inflammation across different treatment settings.

The trial also demonstrates the value of distinguishing design information from results. Randomization, double blinding, a placebo comparison, and a specified rank-based test describe how the primary comparison was structured. They do not disclose the observed outcome distribution. A clear methods description cannot substitute for outcome estimates, uncertainty, and a transparent account of participants included in the analysis.

Multiple outcomes and treatment settings create interpretive demands. Esophagitis and mucositis are related in the trial's clinical context but are distinct endpoints, as are severity, incidence, and duration. Each outcome can answer a different question. The registry lists several such measures, while its multiplicity strategy and results are not reported. Readers therefore need to resist treating the study as a single broad comparison with one answer.

Finally, the record's terminated status and safety counts underline the importance of context. A status label does not explain why a trial ended, and counts alone do not determine causation. In this case, the reason for termination and the primary outcome results are not reported. Recognizing those absences is essential to keeping conclusions proportional to the information available.

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.

Important information needed to assess the primary comparison is not reported in the registry record. This includes the group-specific distribution of esophagitis grades, the primary analysis result, an effect estimate, and its uncertainty. The exact grading scale and the protocol's evaluability definition are also absent. The registry specifies that the primary population met an adherence threshold of at least 60% of planned doses, but does not report how many participants met the criteria or how exclusions affected the comparison.

The record does not report the reason for termination, the final disposition of participants, or whether follow-up and data collection were complete. It also does not describe handling of missing endpoint observations, withdrawal, or sensitivity analyses. These omissions make it difficult to judge whether the analyzed participants represent the randomized groups or whether incomplete data could have influenced results.

Although the trial is described as randomized and double-blind, details of sequence generation, concealment, allocation ratio, masking procedures, and any stratification are not reported in the registry record. The glutamine dose is not stated. The record names multiple secondary outcomes but does not provide their results or a multiplicity plan. Safety summaries do not include attribution or event timing, limiting causal interpretation.

Enrollment is listed as 77, but the primary analysis population is defined more narrowly and its size is not reported. The group-specific at-risk counts in the safety record should not be treated as the primary endpoint denominators. Together, these missing details constrain assessment of precision, bias, completeness, and generalizability. They do not, on their own, establish that the trial's findings were positive or negative.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Randomized Trial of Glutamine in Patients With Mucositis or Esophagitis — NCT01952847.
• Registry record last updated 2022-06-15; status last verified 2022-06.
• Results first posted 2022-06-15.
• 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.

18. Record Summary

NCT01952847 is a Phase 3 randomized, double-blind, parallel-group, placebo-controlled trial sponsored by M.D. Anderson Cancer Center. The record lists enrollment of 77, a start date of 2014-07-10, a primary completion date of 2021-03-03, and a status of terminated. Participants were studied in mTOR inhibitor-based treatment or radiation to the esophagus settings.

The primary endpoint was the highest esophagitis grade observed by week six among radiation-to-esophagus participants meeting the stated per-protocol criteria. The planned comparison used a Wilcoxon rank sum test. Primary outcome results, the reason for termination, missing-data methods, and the multiplicity strategy are not reported in the registry record. The record lists secondary outcomes and group-specific safety counts, but those data do not supply the missing primary comparison or establish treatment causation.