Telotristat With Lutathera in Neuroendocrine Tumors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Telotristat With Lutathera in Neuroendocrine Tumors (NCT04543955), a randomized phase 2 study. The primary outcome is Progression-Free Survival (PFS).

2. Clinical Question

In practical terms, the registered question combines a treatment hypothesis about adding telotristat to Lutetium Lu 177 Dotatate with a comparison of two telotristat dose levels. Those are not the same contrast: an arm receiving one dose versus another can inform a dose comparison, but, without a described arm lacking telotristat, it cannot by itself isolate the contribution of telotristat against Lutathera alone. The registry record does not provide enough arm-level treatment detail to establish precisely how the combination was administered or analyzed.

3. Trial Design

This was a phase 2, randomized, parallel-group study with no masking. Its registered title identifies telotristat in combination with Lutetium Lu177 Dotatate in well-differentiated neuroendocrine tumors. The arm descriptions distinguish low-dose from high-dose telotristat: 750mg per day and 1500mg per day, respectively. The registry record reports one participant enrolled and lists the study status as terminated.

Random allocation is generally used to make treatment groups comparable, on average, with respect to factors that could affect outcomes. That benefit depends on having enough participants for chance imbalances to be limited; with one participant enrolled, the record does not support a meaningful assessment of group comparability or a stable comparison between arms. The allocation sequence, allocation concealment, and numbers assigned to each arm are not reported in the registry record.

With no masking, the study was open-label. In general, knowledge of treatment assignment can affect care, reporting, and outcome assessment, especially when outcomes involve judgment or participant reports. The record does not say whether progression was assessed by reviewers unaware of treatment assignment or according to prespecified imaging criteria.

The study started on 2021-09-13, and the primary completion date is listed as 2022-06-03. The reason for termination and the actual duration of treatment or follow-up are not reported in the registry record. The record does not describe whether Lutathera was given to every participant, nor does it provide a treatment schedule for that drug. The primary outcome timeframe is 20 months, but the record does not explain how that timeframe relates to each participant’s treatment start or follow-up.

Because the only enrollment information is one participant and the outcome description explicitly withholds data for identification risk, the record does not offer an interpretable randomized estimate of the difference between the dose arms. Randomized design describes how assignment was intended to occur; it does not guarantee that a useful comparison resulted when enrollment was this limited.

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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: One participant was enrolled in this study. Due to the possibility that participants could reasonably be identified due to low enrollment, data cannot be presented.

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: Research cancelled and 0 participants enrolled in Arm 2

6. Primary Endpoint

The registry lists the primary outcome as Progression-Free Survival (PFS), measured over 20 months.

The primary outcome is progression-free survival at 20 months. Progression-free survival is generally a time-to-event measure of how long participants remain alive without documented worsening of disease. The registry’s brief outcome description gives the assessment point but does not define the event, identify the assessment criteria, or state how deaths, missed assessments, or other incomplete follow-up were handled. Those details are not reported in the registry record.

Time-to-event outcomes are used in clinical research because participants may have different lengths of follow-up, and the timing of progression can matter as well as whether it occurs. In a conventional analysis, follow-up information is used up to the event or the last time a participant is known to be event-free. Such methods depend on clear event definitions and adequate follow-up information; the record does not provide the individual observations needed to assess either.

A result at a fixed time point can be useful when the clinical question concerns the chance of remaining progression-free at that point. However, a numerical estimate and its uncertainty are needed to understand the result. Neither can be presented from this record: the stated population description says outcome data cannot be presented because one participant was enrolled and identification could be possible. The record therefore identifies the intended endpoint, but does not permit interpretation of the observed progression-free survival result.

The registry also lists median progression-free survival among the secondary outcomes. A median is a summary of the time-to-event distribution, but no median value or analysis is reported. The primary outcome’s 20-month assessment and the secondary median outcome should not be treated as interchangeable summaries.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods are useful only when the data and analysis details needed to apply or assess them are available. In this study, the registry identifies the design and outcomes but does not provide reportable outcome data. It also does not report an analysis plan. The concepts below are general explanations of how clinical-trial methods are commonly interpreted, not claims about methods used in this study.

What does randomization contribute?

Randomization assigns participants to treatment groups using chance. Its purpose is to reduce systematic differences between groups, including differences in measured and unmeasured characteristics. It does not ensure that groups will be alike in every study, and its balancing benefit is limited when very few participants are enrolled. The record identifies randomized allocation but does not report the sequence-generation method, concealment procedures, or allocation details. With one participant enrolled, there is no meaningful group-level basis for judging balance or estimating a treatment contrast.

What would a treatment-effect estimate mean?

A treatment-effect estimate describes the observed contrast between groups for a defined outcome. For a time-to-event endpoint such as progression-free survival, an analysis might compare survival curves or estimate a relative event rate, depending on the prespecified plan and available data. These are general possibilities, not methods documented for this trial. The registry does not report an effect estimate, event information, or analysis method, so no comparative estimate can be interpreted.

How should uncertainty be understood?

A confidence interval is a range of values compatible with the data under a specified statistical procedure. It communicates uncertainty around an estimate; a narrow interval generally indicates greater precision than a wide one. A confidence interval does not show the probability that a particular treatment effect is true, and it cannot correct for weaknesses in study design or data collection. No confidence interval is reported for the primary outcome, and the withheld data do not allow one to be assessed from the registry record.

A p-value, when used, measures how incompatible observed data are with a specified null hypothesis under a statistical model. It does not measure the size or clinical importance of an effect. The registry does not report a p-value or statistical test for the primary outcome. The stated planning framework mentions a two-sided significance level of 0.05, but that is an assumption for a planning illustration, not evidence that a trial analysis used that threshold or that an outcome was statistically significant.

Why does censoring matter for progression-free survival?

In time-to-event analysis, a participant whose event has not been observed by the end of available follow-up may contribute information up to the last known event-free time. This is commonly called censoring. Valid interpretation depends on clear follow-up and event definitions, and on assumptions about why observation ends. The registry does not report participant-level event times, censoring information, or rules for handling incomplete follow-up. Its 20-month endpoint description alone is not enough to reconstruct a time-to-event analysis.

What does the planning illustration represent?

The stated planning framework describes an illustration based on the observed effect, with two-sided significance level 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For time-to-event planning, the framework describes a total event count using the Schoenfeld approach; for other outcomes, it describes participants per arm. These are planning assumptions, not the trial’s own design justification, and the registry does not report a sample-size justification for the study. A planning illustration is not observed power, and it should not be read as evidence about the study’s realized ability to detect an effect. No numerical planning result can be interpreted from the record’s reported outcome information.

How could extra variation affect an analysis?

In general, over-dispersion occurs when observed variability is greater than a statistical model expects. If ignored, it can make uncertainty appear smaller than it is, potentially affecting confidence intervals and tests. Methods that account for extra variation may be appropriate for some count or repeated-measure outcomes, depending on the data and model. The registry does not report a model for response, urinary 5-HIAA, or quality-of-life outcomes, and it does not report evidence about over-dispersion. It would therefore be speculative to say whether an adjustment was necessary or used.

Overall, the registry record does not document the statistical analysis plan, model specifications, assumptions, or handling of missing observations. General descriptions of statistical methods cannot fill those gaps or substitute for the outcome data that were withheld.

10. Multiplicity, Missing Data and Analysis Populations

The registered primary outcome is progression-free survival at 20 months. The record also lists secondary outcomes: overall response rate, median progression-free survival, urinary 5-HIAA, quality of life measured with QLQ-C30, and quality of life measured with QLQ-GI.NET21. It reports six outcome measures and zero analyses, but does not provide results or explain how the outcome measures relate to the analysis set.

When a study examines multiple outcomes, time points, or comparisons, the chance of finding an apparently notable result by chance can increase. Statistical plans may address this through a hierarchy of outcomes, adjustment procedures, or by clearly distinguishing confirmatory from exploratory analyses. The registry does not report whether multiplicity was considered, whether any adjustment was planned, or how the primary and secondary outcomes would be interpreted together. No conclusion about multiplicity control can therefore be drawn.

The record does not describe an analysis population, such as an intention-to-treat population, a per-protocol population, or a safety population. It also does not explain how participants would be classified for analysis, how protocol deviations would be handled, or how missing data would be addressed. These omissions matter because analysis choices can affect which observations contribute to an estimate and how uncertainty is calculated.

The primary outcome description says data cannot be presented because one participant was enrolled and identification could be possible. This is a disclosure limitation, not a statistical method for handling missing values. The record does not indicate whether any analyses were conducted outside the posted registry results, or whether outcome information was collected but withheld. The status of analyses and missing outcome information beyond what is explicitly recorded is not reported in the registry record.

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

The record supports a description of the intended study: a randomized, unmasked, parallel phase 2 comparison of two telotristat doses in well-differentiated neuroendocrine tumors, with progression-free survival at 20 months as the primary outcome. It also reports one participant enrolled, a terminated status, and the stated reason that outcome data cannot be presented because identification could be possible at such low enrollment.

It does not support a conclusion about whether low-dose or high-dose telotristat produced better progression-free survival. There is no reported outcome estimate, uncertainty interval, or test result. The record likewise does not establish whether the study hypothesis about telotristat increasing the antitumor efficacy of Lutetium Lu 177 Dotatate was supported, refuted, or adequately tested.

These limitations should not be converted into a claim of no effect, equal effects, or lack of safety concerns. A result that is unavailable for privacy reasons is not a null finding. Similarly, the zero entries in the listed safety count fields do not establish an absence of adverse events, particularly because the fields for participants at risk are also recorded as 0 and no explanation is given.

The study’s small enrollment sharply constrains what can be learned from the registry record, but the record does not give the reason for that enrollment or for termination. It also does not report the planned analysis, follow-up details, or the reasons any data were unavailable beyond the privacy statement. Interpretations about recruitment barriers, treatment delivery, or trial conduct would therefore go beyond the recorded information.

The most defensible reading is descriptive rather than comparative: the record shows what question was registered and why a numerical outcome is not available. It cannot establish an estimate of treatment effect, precision, or safety for either dose.

12. Why This Trial Matters Statistically

This study is statistically notable because its randomized design and clinical question do not translate into a reportable comparison in the registry record. Randomization is a method for supporting fair comparisons, but it cannot replace outcome information. With one participant enrolled and the explicit privacy concern, the record cannot provide a useful estimate of the difference between the dose arms.

The case also illustrates the distinction between a registered endpoint and an interpretable result. Naming progression-free survival at 20 months identifies the intended measure, but interpretation additionally requires a clear event definition, follow-up information, a method of analysis, and an estimate with uncertainty. Those details are not reported. A well-defined endpoint is necessary for a treatment comparison, but it is not sufficient on its own.

Another important distinction is between statistical planning and observed evidence. The record describes assumptions for a planning illustration, including the significance level and allocation approach. Such assumptions do not show that the study was designed with a particular justification, nor do they establish the precision of an observed treatment effect. Planning calculations and trial results answer different questions.

Finally, a terminated status and suppressed outcome data should be interpreted cautiously. The record does not state why the study ended, and privacy-based non-disclosure is not evidence of either a favorable or unfavorable result. For researchers, the example emphasizes the importance of reporting design and analysis details while protecting confidentiality, and of distinguishing unavailable results from results that show no difference.

13. 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 most consequential trial-specific limitation is the reported enrollment of one participant. This leaves no interpretable randomized comparison between the low-dose and high-dose arms in the posted record. The registry explicitly says the outcome data cannot be presented because participants could reasonably be identified. There are therefore no reportable primary-outcome estimates or secondary-outcome results to evaluate.

The study is listed as terminated, but the reason for termination is not reported in the registry record. The record also does not state whether the participant completed treatment or follow-up, whether the primary outcome was assessed, or how the listed 20-month timeframe was applied. It is not possible to determine from the record whether termination affected data collection or analysis.

Although the title describes telotristat with Lutathera, the intervention and arm descriptions specify the telotristat dose levels without detailing Lutathera administration. The record does not explain the full treatment regimen or provide a comparator arm without telotristat. This limits clarity about the contrast intended to test the stated hypothesis.

Important methodological details are also absent: eligibility criteria beyond the tumor description, allocation procedures, event definitions, outcome assessment methods, analysis populations, missing-data handling, and the statistical analysis plan are not reported in the registry record. The safety fields show 0 for each listed count, including at-risk counts, without an explanation that would support a safety interpretation.

These limitations concern the information available in the registry record. They do not establish why enrollment was limited, why the study was terminated, or whether additional analyses exist elsewhere.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Telotristat With Lutathera in Neuroendocrine Tumors — NCT04543955.
• Registry record last updated 2023-06-27; status last verified 2023-06.
• Results first posted 2023-06-27.
• 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.

17. Record Summary

The registry record describes a randomized, unmasked, parallel phase 2 study titled “Telotristat With Lutathera in Neuroendocrine Tumors.” It lists low-dose telotristat at 750mg per day and high-dose telotristat at 1500mg per day. The primary outcome is progression-free survival at 20 months. Listed secondary outcomes include overall response rate, median progression-free survival, urinary 5-HIAA, and quality of life measured with QLQ-C30 and QLQ-GI.NET21.

The record reports one participant enrolled, a start date of 2021-09-13, a primary completion date of 2022-06-03, and a terminated status. It states that outcome data cannot be presented because identification could be possible at the reported enrollment. The reason for termination, analysis plan, and numerical outcome results are not reported in the registry record.

The record lists two telotristat dose arms but does not detail Lutathera dosing or a Lutathera-only comparator. Its safety count fields are recorded as 0, including participants at risk, without further explanation. The available information describes the intended question and design, but does not support a treatment-effect or safety comparison.