Phase 2A Clinical Trial Evaluating the Potential Activity and Safety of hMaxi-K Gene for ED: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Phase 2A Clinical Trial Evaluating the Potential Activity and Safety of hMaxi-K Gene for ED (NCT02713789), a randomized phase 2 study. The primary outcome is Number of Participants With Adverse Experiences as Measured by Changes in Physical Examination of the Penis.

2. Clinical Question

The registry record also describes the broader purpose as evaluating safety and potential activity on penile rigidity or erection. The posted primary endpoint is specifically a safety count; it is not a direct measure of erectile function or sexual activity. Secondary outcomes listed in the record include changes in Sexual Encounter Profile responses and International Index of Erectile Function domains at Week 24.

The clinical question therefore has two parts that should be kept distinct. The primary reported result concerns findings on penile examination. The listed secondary outcomes concern patient-reported aspects of sexual function and satisfaction. The results discussed for the primary endpoint cannot, by themselves, answer whether hMaxi-K changed those secondary measures. The record describes a placebo comparison and two hMaxi-K dose groups, allowing each dose group’s posted primary count to be considered alongside the placebo count, while the available comparative analysis is limited as described in the statistical interpretation.

3. Trial Design

This was a randomized, double-blind, parallel-design Phase 2A clinical trial. The registry record lists erectile dysfunction as the condition and Urovant Sciences GmbH as the sponsor. The study began in 2015-04, its primary completion date is 2017-08-24, and its status is completed. Enrollment is reported as 26.

The treatment design included a single injection of hMaxi-K at 8000 µg or 16000 µg, and a placebo injection described as PBS-20% sucrose. The arm descriptions specify one injection per participant. The posted primary endpoint results list hMaxi-K 8000 µg, hMaxi-K 16000 µg, and placebo, with analyzed group sizes of 8.0, 10.0, and 8.0, respectively. These are the group sizes associated with the posted primary endpoint, rather than a reconstructed total or a claim about all randomized participants.

Double masking and randomization are design features intended to limit bias in treatment assignment and assessment. The registry record does not report the particular randomization procedure, the people or roles covered by masking, or how masking was maintained. It also does not report further details of the allocation process. Those omissions mean the design can be characterized at the level recorded, but its implementation cannot be assessed from these details alone.

The record describes the intended study population as males with erectile dysfunction longer than six months attributable to an underlying, stable medical condition. It does not provide additional eligibility criteria in the registry record reported for this analysis. The primary endpoint’s safety population is described as randomized participants who received at least one dose of study treatment. How that population relates to each secondary outcome’s analysis population is not reported in the registry record.

The registry includes seven posted secondary outcomes, covering Sexual Encounter Profile responses and domains of the International Index of Erectile Function at Week 24. The findings addressed focus on the primary penile-examination safety outcome; the listed secondary outcomes are not substitutes for that endpoint and are not interpreted as if their results were available.

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: Safety Population: all participants who were randomized to any of the treatment groups and who have received at least one dose of study 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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Adverse Experiences as Measured by Changes in Physical Examination of the Penis, measured over up to Week 24 ± 3 days.

The primary endpoint counts participants with adverse experiences measured by changes in physical examination of the penis. The registry specifies that the examination involved inspection and palpation, and gives the assessment period as up to Week 24 ± 3 days. The outcome is a participant count, not a continuous measure of rigidity, erectile function, or change in a questionnaire score.

A physical examination can provide a structured way to monitor findings in the anatomical area relevant to an intracavernous injection. Counting participants with a recorded adverse experience gives a safety-focused description of whether such findings were reported during the stated follow-up period. In general, a count is straightforward to interpret as a number of people meeting the endpoint definition, but a count alone does not communicate the severity, duration, or clinical importance of each event. Those details would require additional event-level information.

The posted result is 0.0 in the hMaxi-K 8000 µg group, 0.0 in the hMaxi-K 16000 µg group, and 0.0 in the placebo group. These results refer only to the defined penile-examination endpoint. They should not be generalized to every possible adverse experience, to other safety measures, or to the trial’s secondary efficacy-related outcomes. The registry record does not report further detail about the criteria used to classify a change on examination as an adverse experience.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a participant-count endpoint, with the endpoint defined as the number of participants having adverse experiences measured by changes in penile physical examination. The posted values are counts, and the primary outcome is identified as binary in the analysis information: each participant either meets the stated endpoint definition or does not. This format differs from an outcome such as a change in a questionnaire score, where the result would be expressed on a numerical scale.

What does a count tell the reader?

A count describes how many participants met an outcome definition in a group. To interpret a count, it is important to consider the group size and how the outcome was defined. The posted primary results pair group counts with analyzed group sizes: 0.0 for hMaxi-K 8000 µg with 8.0 participants, 0.0 for hMaxi-K 16000 µg with 10.0 participants, and 0.0 for placebo with 8.0 participants. These figures allow the result to be read in the context of the corresponding groups without implying a broader population-level guarantee.

In general, a confidence interval expresses uncertainty around an estimated quantity. For a binary event, an interval around an event frequency or a between-group contrast can show that the data may be compatible with a range of underlying values. When no events are observed in a group, uncertainty does not disappear; the available sample may still be compatible with a nonzero event frequency. No confidence interval for the primary endpoint is reported in the registry results, so the precision of the group estimates cannot be assessed from an interval.

Why is a comparison not available?

The registry analysis notes that values are missing or not estimable for a two-arm comparison of this binary endpoint. It therefore does not give a comparative estimate for hMaxi-K versus placebo in the posted primary result. The group counts can still be described, but a count-by-count inspection is not a substitute for a defined comparative analysis. The record does not report the specific computational reason or method behind the unavailable estimate. In general, an analysis method must be suitable for the observed data; sparse event information can make some comparative procedures unstable or not estimable.

No recalculated comparison is reported for this endpoint. The registry record does not report a sponsor-computed inferential comparison for the primary endpoint in the registry record, and no alternative effect estimate should be inferred from the three group counts.

How should planning estimates be read?

In general, a sample-size illustration uses assumptions about the effect a future study aims to detect, the significance level, allocation, and statistical method. The planning assumptions recorded for this trial’s illustration include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as stated fractions of the observed effect. Such calculations are planning illustrations, not estimates of what the trial demonstrated and not observed power. The record’s convention is to express non-time-to-event planning results as participants per arm for 80% power; time-to-event results are expressed as total events. These general conventions do not add evidence to the observed primary endpoint findings.

What do randomization and masking contribute?

In general, randomization aims to reduce systematic differences in treatment assignment, while masking can reduce the influence of treatment knowledge on care, reporting, or assessment. This trial is described as randomized and double-blind, but the registry record does not report the randomization method, allocation concealment procedure, masking roles, or details of maintaining the blind. The design labels should therefore be understood as the features recorded, not as a complete account of their implementation.

The analysis population stated for the primary endpoint is the safety population: randomized participants who received at least one dose of study treatment. This definition is relevant because the people contributing to a safety count need not automatically be the same population used for every other outcome. The record does not report further details on endpoint-specific exclusions, handling of missing assessments, or the statistical model for the posted count. Those elements limit the extent to which the analysis can be independently reconstructed.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("hMaxi-K 8000 µg", "hMaxi-K 16000 µg", "Placebo")
n      <- c(8, 10, 8)
events <- c(0, 0, 0)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  hMaxi-K 8000 µg  8  0  0.0  0.0  36.9  0.0  32.4  0.3  33.6
ARM  hMaxi-K 16000 µg  10  0  0.0  0.0  30.8  0.0  27.8  0.2  28.5
ARM  Placebo  8  0  0.0  0.0  36.9  0.0  32.4  0.3  33.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 7 secondary outcomes, including Sexual Encounter Profile responses and several International Index of Erectile Function domains measured at Week 24. It also records 34 analyses. Testing or estimating many outcomes can raise multiplicity concerns: in general, when many hypotheses are considered, the chance of at least one apparently noteworthy result can increase unless the analysis plan addresses that issue. Multiplicity adjustment is not reported in the registry record, so it is not possible to determine whether or how the secondary analyses accounted for multiple comparisons.

The reported primary endpoint is a safety outcome with a stated safety population of randomized participants who received at least one dose of study treatment. That population definition is available for the primary endpoint, but the analysis populations for the secondary outcomes are not reported in the registry record. The record also does not report a statistical plan explaining which outcomes were intended to be confirmatory or how outcomes were prioritized.

Details about missing data are not reported in the registry record. In particular, the registry entries do not describe the amount or pattern of missing endpoint assessments, the handling of participants without a Week 24 assessment, or any imputation approach. In general, missingness can affect estimates if the participants with observed outcomes differ systematically from those without them. Without the relevant details, the extent of any such effect cannot be assessed.

These omissions do not change the posted primary counts, but they constrain interpretation of the broader outcome set. The record supports a description of the primary safety endpoint and the listed outcomes, while leaving uncertainty about secondary-outcome analysis populations, multiplicity procedures, and missing-data handling.

12. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: eye operation (12.5%), osteoarthropathy (12.5%).

The registry’s serious adverse experience summary reports 1 participant affected in the hMaxi-K 8000 µg group, 0 in the hMaxi-K 16000 µg group, and 1 in the placebo group. The corresponding numbers at risk are 8, 10, and 8. The record lists Eye operation and Osteoarthropathy among the top serious terms, each with a reported frequency of 12.5%. It does not assign those terms to particular treatment groups in the registry record analyzed.

For other adverse experiences, the summary reports 8 affected among 8 at risk for hMaxi-K 8000 µg, 10 among 10 for hMaxi-K 16000 µg, and 8 among 8 for placebo. Deaths are reported as 0 in each group. These are separate safety summaries; they should not be confused with the primary endpoint, which counts adverse experiences measured by changes in penile physical examination and has a posted value of 0.0 for each group.

In general, a serious adverse experience is a different category from the broader set of adverse experiences, and event counts alone do not establish whether treatment caused an event. The registry record does not report causal attribution for the listed serious experiences, event-level timing, or severity details beyond their categorization. The group summaries are descriptive and should not be taken as a comparative safety test.

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

The primary result means that the registry recorded no participants meeting the defined penile-examination adverse-experience endpoint in the hMaxi-K 8000 µg group, the hMaxi-K 16000 µg group, or the placebo group. The endpoint was based on physical examination by inspection and palpation during follow-up up to Week 24 ± 3 days. This finding is specific to that endpoint and assessment period.

It does not mean that there were no adverse experiences of any kind. The separate safety summary reports other adverse experiences in each group, as well as serious adverse experiences in the hMaxi-K 8000 µg group and placebo group. Nor does the primary result establish that either hMaxi-K dose has the same risk as placebo. The available record does not provide a two-arm comparative estimate for this binary endpoint, and the observed counts alone cannot establish equivalence or exclude an underlying risk.

The result also does not answer whether hMaxi-K changed erectile function, penile rigidity, or sexual satisfaction. Those topics appear in the trial purpose and secondary outcomes, but the primary endpoint is a safety count. The numerical findings for the secondary outcomes are not reported in the registry record used for this interpretation, so no conclusion about their direction or magnitude is warranted.

In general, results from a randomized, masked, placebo-controlled study can help describe outcomes under the trial conditions, while precision and applicability depend on the amount and quality of observed data and on the analysis. Here, the primary result is descriptive, and the unavailable comparison, absence of an interval estimate, and missing information about missing data and analysis details limit what can be concluded. The appropriate reading is narrow: no participants were recorded with this specified examination-based adverse experience in the posted primary results, while broader safety and activity questions require their own outcome data and analysis.

14. Why This Trial Matters Statistically

This trial illustrates why the endpoint definition matters as much as the broad label of safety. The primary outcome is not a count of every adverse experience; it is a count of participants with adverse experiences measured by changes in penile physical examination. The registry specifies inspection and palpation and gives a follow-up period through Week 24 ± 3 days. A result for that narrow outcome should not be generalized to all safety events.

It also demonstrates the distinction between descriptive group results and a comparative treatment estimate. The posted primary counts are 0.0 for each group, but the registry does not provide an estimable two-arm comparison. Describing the observed counts is informative, yet it does not establish that the groups are equivalent or that the underlying risks are identical. In general, comparative inference requires an estimate and an assessment of its uncertainty, not only a visual comparison of group counts.

The separate serious and other adverse experience summaries further show that safety can be represented through multiple outcome definitions. Those broader summaries contain events even though the primary examination-based endpoint has zero counts in the posted results. Keeping these outcomes distinct prevents a narrow finding from being mistaken for a complete safety profile.

Finally, the registry lists multiple secondary outcomes and many analyses, while details of multiplicity adjustment, missing data, and the analyses for those outcomes are not reported in the registry record. For clinical researchers, this is a reminder that outcome hierarchies and analysis details are essential to interpreting a broad set of results. The trial’s statistical value lies not in a single count alone, but in how clearly each outcome is defined, how comparisons are estimated, and how uncertainty and analysis choices are documented.

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 primary endpoint is a narrowly defined safety measure, not a comprehensive account of adverse experiences or a direct measure of erectile function. The registry reports counts but does not provide event-level details about examination findings, duration, severity, or clinical significance. The record also does not report further criteria for deciding when a physical-examination change qualified as an adverse experience.

The posted primary result has no observed events in any group, and the record states that a two-arm comparison for this binary endpoint is missing or not estimable. No confidence interval or comparative effect estimate is reported in the registry record. Consequently, the precision of the group results and the range of underlying risks compatible with the observations cannot be evaluated from the posted summary alone.

Although the study is described as randomized and double-blind, the registry record does not report the randomization method, allocation concealment, masking details, or procedures used to maintain masking. The record also does not report a statistical analysis plan, multiplicity adjustment, missing-data methods, or the analysis populations for the secondary outcomes. These omissions limit assessment of potential analysis and reporting choices.

The broader safety summary includes serious and other adverse experiences, but the registry entries do not state whether individual events were considered related to treatment. The listed serious terms are not tied to a specific group in the reported details. The listed secondary outcomes concern sexual function and satisfaction, but their numerical results are not included in the registry record. Thus, neither the primary safety count nor the broader safety summaries can establish the trial’s effects on those secondary outcomes.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Phase 2A Clinical Trial Evaluating the Potential Activity and Safety of hMaxi-K Gene for ED — NCT02713789.
• Registry record last updated 2019-08-08; status last verified 2019-07.
• Results first posted 2019-08-08.
• 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.

19. Record Summary

The registry record describes a completed, randomized, double-blind, parallel-design Phase 2A trial of single intracavernous hMaxi-K injections at 8000 µg or 16000 µg compared with placebo in males with erectile dysfunction. Total enrollment is 26. The primary endpoint counts participants with adverse experiences measured by changes in penile physical examination, through Week 24 ± 3 days.

The posted primary values are 0.0 for hMaxi-K 8000 µg, 0.0 for hMaxi-K 16000 µg, and 0.0 for placebo. The record does not provide an estimable two-arm comparison for this binary outcome. Separate safety summaries report serious and other adverse experiences, and the registry lists secondary outcomes concerning sexual function and satisfaction. Details on multiplicity adjustment, missing-data handling, and secondary-outcome analysis populations are not reported in the registry record.