IX-01 Effect on Intravaginal Ejaculatory Latency Time (IELT) and Patient Reported Outcomes in Men With Premature Ejaculation (PE): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for IX-01 Effect on Intravaginal Ejaculatory Latency Time (IELT) and Patient Reported Outcomes in Men With Premature Ejaculation (PE) (NCT02232425), a randomized phase 2 study. The primary outcome is Mean Fold Change in Geometric Mean Intravaginal Ejaculatory Latency Time (IELT).

2. Clinical Question

The study asks whether the geometric mean fold change in intravaginal ejaculatory latency time (IELT) differs between men assigned to IX-01 and men assigned to placebo. The primary outcome compares IELT during the last 4 weeks of treatment with baseline, using the efficacy data set that excludes outliers.

IELT was defined as the time from initiation of sexual intercourse (penetration) until ejaculation occurred. The registry record also lists secondary outcomes concerning participants’ assessments of change, IELT fold change, control of ejaculation, personal distress, and satisfaction or related experiences reported on the Premature Ejaculation Profile questionnaire. Those outcomes broaden the questions beyond elapsed time, but the primary endpoint focuses on the fold change in geometric mean IELT.

3. Trial Design

This was a Phase 2, randomized, double-blind, parallel-group study with placebo control. Its official title describes an 8-week study. The registry record lists an enrollment of 88 and a completed status. The study began in 2014-09, and primary completion was recorded as 2015-10. Ixchelsis Limited is listed as the sponsor.

Participants were assigned to IX-01 or placebo. The IX-01 arm description specifies two to four 200 mg capsules taken orally 1-6 hours prior to sexual activity; the placebo description specifies two to four capsules with the same timing. The registry record does not report the allocation ratio, and it does not describe further details of the randomization procedure. Double masking means that the design intended to keep treatment assignment concealed from relevant participants or study personnel, but the registry record does not describe how masking was maintained or assessed.

A parallel-group design compares the assigned groups over the same study period rather than switching participants between treatments. Randomization is intended, in general, to reduce systematic differences between groups at assignment; masking can reduce the influence of treatment expectations on assessment or reporting. These are general design principles, not evidence about how completely those protections operated in this study.

The primary outcome was defined as mean fold change in geometric mean IELT, comparing the last 4 weeks of treatment with baseline. The primary population was an efficacy data set excluding outliers. The registry record does not report the criteria for identifying outliers, the planned sample-size justification, or further operational details about the analysis.

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: Efficacy data set excluding outliers

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.

6. Primary Endpoint

The registry lists the primary outcome as Mean Fold Change in Geometric Mean Intravaginal Ejaculatory Latency Time (IELT), measured over Last 4 weeks of treatment compared to baseline.

The primary endpoint measures how IELT changed from baseline on a fold-change scale, using the geometric mean. IELT is the time from penetration to ejaculation. The comparison uses the last 4 weeks of treatment and baseline, and is specified as IX-01 versus placebo. The registry record gives an estimate and a 95% confidence interval for each arm in the efficacy data set excluding outliers.

A fold-change measure expresses change multiplicatively rather than as an absolute change in time. The geometric mean is a way of summarizing measurements on a multiplicative scale. As a general statistical point, time measurements can have asymmetric distributions, and geometric summaries can be useful when the scientific question concerns proportional change. The registry record does not state the rationale for choosing this summary or give the distribution of individual IELT observations.

The endpoint is used to represent change in a measurable aspect of sexual function over the treatment period. It does not, by itself, capture every experience associated with premature ejaculation. That is why the registry record also lists patient-reported and other secondary outcomes, including perceived improvement, control, distress, and satisfaction. The primary endpoint remains a measure of IELT fold change, not a complete measure of participants’ overall experience.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is reported as a geometric mean fold change, with a 95% confidence interval for each arm. A fold change expresses a relative change from baseline rather than a difference measured in units of time. The reported values therefore summarize proportional change in IELT, not an average number of additional minutes. The registry record lists no units for fold change.

What does a geometric mean summarize?

As a general statistical explanation, the arithmetic mean summarizes values by adding them and dividing by their count, whereas the geometric mean summarizes positive values on a multiplicative scale. This can be useful when observations vary proportionally or are asymmetric. The geometric mean is not the same as the arithmetic mean, and it should not be interpreted as the typical participant’s exact observed value. The registry record does not report the individual observations or describe the distribution of IELT in this study.

For the primary outcome, the comparison is between the last 4 weeks of treatment and baseline, with IX-01 evaluated against placebo. The reported estimate for IX-01 is 2.1, with a 95% confidence interval of 1.5 to 3.1; the placebo estimate is 1.1, with a 95% confidence interval of 0.7 to 1.8. These are arm-level estimates. They are not themselves a treatment-versus-placebo contrast, and no contrast estimate or test result is posted in the registry record.

What does the confidence interval convey?

In general, a confidence interval gives a range of estimates compatible with the observed data under a particular statistical procedure and its assumptions. A narrower interval indicates greater precision than a wider interval, all else being comparable. The interval does not show the full range of individual participant outcomes, and it is not a prediction interval for what a future participant will experience. It also does not provide a direct test of the difference between two arms when reported separately for each arm.

The confidence intervals are important because an estimate alone can hide uncertainty. Here, each arm estimate is accompanied by an interval, but the registry record does not give the analysis details needed to reproduce the intervals. It does not report a standard error, the exact modeling procedure, or an inferential result for the between-group comparison. Those items are not reported in the registry record.

Why does the analysis population matter?

The primary outcome population is described as an efficacy data set excluding outliers. This means the result pertains to the observations included under that definition. Excluding outliers can affect an estimate, especially if unusual observations have substantial influence; that is a general statistical consideration, not a claim that the posted result was changed by particular observations. The criteria for outlier identification and the number or characteristics of exclusions are not reported in the registry record. The record also does not describe a sensitivity analysis using a different outlier rule or including excluded observations.

Random assignment and masking are design features, not analysis results. In general, randomization supports a fair comparison by reducing the chance that pre-existing characteristics systematically determine group assignment. Masking can reduce the influence of expectations on behavior, reporting, or assessment. The record identifies the study as randomized and double-blind, but it does not describe allocation concealment, the masking procedure, or checks on masking. It is therefore appropriate to describe the stated design without assuming details that are not recorded.

What can be inferred from the posted estimates?

The estimates describe change from baseline within each assigned arm. To quantify the comparative effect, an analysis would ordinarily report a contrast between arms with its uncertainty, or a suitable test of that contrast. The registry record does not post such a primary comparison. It is not appropriate to create a new contrast by subtracting or dividing the arm summaries, because that would not reproduce a sponsor analysis and would not account for the analysis structure or uncertainty.

General statistical practice also distinguishes statistical uncertainty from clinical importance. A confidence interval describes precision under a model; it does not determine whether an effect matters to participants. The record does not specify a threshold for a clinically important change in IELT, and no threshold should be inferred from the estimates alone.

The registry record lists planning assumptions for sample-size illustrations: a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect defined as a stated fraction of the observed effect. Such calculations are planning illustrations based on the observed effect, not observed power and not evidence that the original trial was designed around those assumptions. The sample-size justification for the trial itself is not reported in the registry record. The posted record also contains no analysis entries for a distinct two-arm comparison, and it indicates that another endpoint lacked values or was not estimable for such a comparison.

Over-dispersion is a general issue that arises when observed variability exceeds what a chosen statistical model expects. If present, it can make standard errors too small and confidence intervals too narrow unless the analysis accounts for it. The registry record does not report an over-dispersion assessment or identify a model for which this issue can be evaluated. It should therefore be treated as a general methodological consideration, not as a demonstrated problem in this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 13 outcome measures and 12 posted secondary outcomes, spanning perceived change, IELT fold change, control, distress, and satisfaction. Examining multiple outcomes can increase the chance of a seemingly notable finding arising by chance if many tests are conducted. Statistical plans may address this with a prespecified hierarchy, adjustment, or other strategy, but the registry record does not report a multiplicity-control method or a hierarchy for interpreting the outcomes. It also does not provide a complete set of inferential results across the outcomes.

The primary analysis population is described as an efficacy data set excluding outliers. The outlier definition, exclusion process, and number of exclusions are not reported in the registry record. Missing-data methods are also not reported: the record does not explain how missing baseline or follow-up IELT measurements were handled, whether participants with incomplete observations were included in particular analyses, or whether sensitivity analyses were conducted. These details matter because results can depend on which observations contribute and on assumptions about missingness.

The registry record reports an enrollment of 88, but the primary outcome results are listed for 54 in the IX-01 arm and 25 in the placebo arm. Safety figures use separate risk-set counts. The record does not explain the relationship between these analysis populations, the reasons for the different counts, or whether exclusions reflect missing data, outlier handling, or other criteria. The result should therefore be interpreted in relation to its stated efficacy population rather than presumed to represent every enrolled participant.

The record does not report an intention-to-treat analysis, a per-protocol definition, or a prespecified missing-data strategy. Those methods should not be assumed. The absence of these details limits assessment of the robustness of the posted outcome estimates and of how the results would change under alternative analytic choices.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry record lists serious adverse events for 0 of 56 participants at risk in the IX-01 group and 0 of 30 participants at risk in the placebo group. These are the posted serious-event counts for the stated risk sets. The record does not list serious adverse event terms, and death counts are not reported in the registry record.

The figures for other adverse events are 12 of 56 at risk in the IX-01 group and 9 of 30 at risk in the placebo group. These are counts, not a comparison adjusted for time at risk, baseline characteristics, or other factors. The registry record does not give event descriptions for these counts in the information summarized by the posted results, so they do not indicate which events occurred or their severity.

A zero serious-event count in the registry entry does not establish that serious events are impossible or that the treatments have equivalent safety. Safety estimates are limited by the study’s size, duration, event definitions, and reporting. The registry record does not provide enough detail to assess all of those factors or to draw conclusions about uncommon events. These figures describe what is recorded for this study and should not be treated as individualized medical guidance.

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

The posted result describes arm-specific changes in geometric mean IELT from baseline to the last 4 weeks of treatment. IX-01 is reported with a fold-change estimate of 2.1 and a 95% confidence interval of 1.5 to 3.1; placebo is reported with an estimate of 1.1 and a 95% confidence interval of 0.7 to 1.8. These estimates give a statistical description of the outcome in the stated efficacy data set, which excludes outliers.

The record does not post a direct estimate of the IX-01-versus-placebo difference, its confidence interval, or a p-value for the primary comparison. The separate arm estimates cannot replace those quantities. As a result, the precision of the comparative effect and the strength of evidence for a between-arm difference cannot be determined from the posted primary results alone.

The outcome is a measure of elapsed time during intercourse, expressed through fold change in a geometric mean. It does not measure every dimension of premature ejaculation or participants’ overall experience. The registry record lists secondary measures related to perceived improvement, control, distress, and satisfaction, but those outcomes do not change what the primary endpoint represents.

The record also does not establish that any observed change was caused by the assigned treatment. Randomization and masking are design strengths in general, but interpretation still depends on the analysis population, missing data, outcome reporting, and the unreported details of the analysis. Nor can a result from this study alone establish how findings apply in other populations, settings, or treatment periods. The posted data are best read as estimates with stated uncertainty and important limits on comparative interpretation.

13. Why This Trial Matters Statistically

This study is statistically notable for pairing an objective timing outcome with patient-reported secondary outcomes. IELT is defined as the time from penetration to ejaculation, while the secondary outcomes include perceived improvement, control, distress, and satisfaction. These measures address different aspects of the research question and should not be treated as interchangeable. A timing estimate can describe change in IELT without capturing how participants evaluate that change.

The primary endpoint also illustrates the importance of the scale used to summarize an outcome. Geometric mean fold change is a multiplicative summary, not an absolute difference in time. Readers need to keep that scale in mind when interpreting the arm estimates and their confidence intervals. The registry record does not post the direct between-group contrast, which is the key quantity for assessing the comparative question.

The stated efficacy population excludes outliers, while the enrollment and safety records use their own counts. This makes analysis-population definitions important to interpretation. Without details on outlier criteria, missing data, and the relationship between populations, readers cannot fully assess how representative the primary estimates are of all enrolled participants.

Finally, the record lists a range of secondary outcomes but does not report a multiplicity strategy. When several outcomes are considered, selective emphasis or chance findings can complicate interpretation. The statistical lesson is to read endpoint definitions, populations, uncertainty, and reporting completeness together rather than treating a single estimate as a complete account of comparative evidence.

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 primary result is reported for an efficacy data set excluding outliers, but the registry record does not define an outlier or describe how exclusions were determined. This limits assessment of whether the analysis could be sensitive to the exclusion rule. The number of excluded observations and their influence on the estimates are not reported in the registry record.

The record provides arm-specific estimates and confidence intervals, but not a direct primary treatment-versus-placebo contrast, confidence interval for that contrast, or p-value. It therefore does not provide the central inferential quantity needed to assess the comparative effect directly. The analysis method used to produce the arm estimates and intervals is not described in enough detail to evaluate or reproduce it.

Missing-data methods and the relationship between the primary efficacy population and the safety risk sets are not reported. The registry record does not explain why the primary outcome counts differ from the safety counts, or how incomplete outcome observations were handled. The record also does not report a multiplicity strategy for the primary and secondary outcomes, or a complete inferential analysis across the outcomes.

The study is described as Phase 2, randomized, double-blind, and placebo-controlled, but the registry record does not provide details of allocation concealment, masking procedures, or checks on masking. The protocol’s sample-size justification and detailed statistical plan are not reported in the registry record. These limits concern the information available in the record; they should not be mistaken for proof that a procedure was absent from the conduct of the study.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: IX-01 Effect on Intravaginal Ejaculatory Latency Time (IELT) and Patient Reported Outcomes in Men With Premature Ejaculation (PE) — NCT02232425.
• Registry record last updated 2020-08-17; status last verified 2020-08.
• Results first posted 2019-01-24.
• 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

NCT02232425 is a completed Phase 2 randomized, double-blind, placebo-controlled parallel-group study sponsored by Ixchelsis Limited. The official title describes an 8-week evaluation of IX-01 in men with lifelong premature ejaculation. Enrollment was 88; the study began in 2014-09, and primary completion was recorded as 2015-10.

The primary outcome was mean fold change in geometric mean IELT during the last 4 weeks of treatment compared with baseline, in an efficacy data set excluding outliers. The posted arm estimates are 2.1 (95% confidence interval 1.5 to 3.1) for IX-01 and 1.1 (0.7 to 1.8) for placebo. A direct between-group estimate and inferential test are not reported in the registry record. The record also lists secondary patient-reported outcomes and adverse-event counts, with important analysis and reporting details not reported.