Effectiveness of onaBoNT-A vs Oral Tamsulosin in Men With BPH and LUTS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of onaBoNT-A vs Oral Tamsulosin in Men With BPH and LUTS (NCT01589263), a randomized phase 2 study. The primary outcome is American Urologic Association Symptom Score (AUASS).

2. Clinical Question

The stated objective is to compare treatment effects in men with BPH-related symptoms. The score captures symptom severity, with higher scores representing worse outcomes. The record describes a randomized, parallel-group study and identifies the outcome population as volunteers randomized by the MEDVAMC Research Pharmacy. It does not provide additional details about eligibility criteria beyond those included in the trial description, nor does it report a separate primary analysis population.

3. Trial Design

The registry record identifies this as a Phase 2 randomized, parallel-group trial. It reports triple masking, while the brief trial description calls the study double-blind. The record does not explain the difference between those masking descriptions or identify which roles were masked. The two assigned strategies combine an injection with a daily capsule: onaBoNT-A 200 U plus oral placebo, compared with saline injection plus tamsulosin 0.4 mg.

The planned enrollment described in the trial summary was 74 volunteers. The registry record lists enrollment of 63. These are different record entries: the planned recruitment figure in the summary should not be treated as the number enrolled, and the enrollment figure should not be treated as the number included in the posted primary outcome. For the outcome, the arm summaries list 9 participants in the onaBoNT-A arm and 12 in the saline plus tamsulosin arm. The record does not explain why these outcome counts differ from the enrollment figure.

The primary outcome is the American Urological Association Symptom Score at 3 months. Results are reported as means with standard deviations. The record marks the study completed and gives a start date of 2012-06-01 and a primary completion date of 2019-09-30. It identifies the VA Office of Research and Development as sponsor. No additional allocation details, such as the method used to generate the random sequence or conceal assignments before enrollment, are reported in the registry record.

Although randomization can reduce baseline differences between groups on average, it does not ensure balance in every realized trial, particularly when outcome group counts are limited. The record does not post baseline characteristics or an adjusted analysis to help assess group comparability. It also does not describe the statistical plan or explain whether the primary analysis followed the original assignment regardless of treatment received.

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

Analysis population for the primary outcome, as defined in the registry: Volunteers were randomized on a 1:1 assignment by the MEDVAMC Research Pharmacy to either: ARM 1: BoNT-A 200 U prostate injection and placebo oral capsule daily or ARM 2: Placebo prostate injection (saline) and Tamsulosin 0.4 mg capsule daily.

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 American Urologic Association Symptom Score (AUASS), measured over 3 months.

The primary endpoint is the American Urological Association Symptom Score, abbreviated AUASS in the registry record, measured at 3 months. It is a continuous symptom score on a scale from 0 to 35. A score of 0 is described as the best outcome and 35 as the worst outcome, so higher values indicate greater symptom burden. The outcome population is described as volunteers randomized to one of the two assigned strategies.

A symptom score is used to represent the reported severity of lower urinary tract symptoms in a standardized form. In general, a continuous measure preserves information across its range rather than reducing each participant to a yes-or-no outcome. Group means can describe the average score in each arm, while the standard deviation describes variation among observations within an arm. Neither summary by itself shows how precisely the groups differ.

The registry record reports a mean of 18.66 with a standard deviation of 0.07 for onaBoNT-A plus placebo, based on 9 participants. For saline plus tamsulosin, it reports a mean of 14.16 with a standard deviation of 0.05, based on 12 participants. These are arm-level summaries at the stated assessment time. The record does not report confidence intervals, participant-level distributions, or an estimable statistical comparison of the continuous endpoint. It therefore does not provide a reported estimate of the between-arm contrast or its uncertainty.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods help distinguish a description of the observed participants from an estimate of a treatment contrast. In this trial, the registry record reports mean AUASS values and standard deviations at 3 months, but no estimable comparison between arms. The following concepts explain what those reported summaries can and cannot convey.

What does the mean describe?

For a continuous outcome, the mean is the arithmetic average of the observed values in a group. It gives a compact description of the group’s central level on the measured scale. Here, the reported mean is 18.66 for onaBoNT-A plus placebo and 14.16 for saline plus tamsulosin. Because the score is defined so that higher values are worse, the means describe the average scores in the two posted groups. A mean does not show whether individuals had similar scores or whether the group included a wide range of values.

What does the standard deviation describe?

The standard deviation describes how dispersed observations are around a group mean. A smaller standard deviation indicates less variation around that mean, assuming the measure and calculation are understood as intended. The registry record labels the reported dispersion as standard deviation and lists 0.07 and 0.05. It does not provide a distribution, participant-level values, or a clarification of these unusually small entries relative to a scale ranging from 0 to 35. The values should be reported as entered, while recognizing that the record does not resolve their interpretation beyond naming the measure.

Why is a contrast and confidence interval useful?

A treatment comparison ordinarily summarizes how much the outcome differs between assigned groups and how uncertain that estimate is. A confidence interval is a range of values compatible with the data and the assumptions of the analysis; it communicates precision, not the probability that a particular treatment effect is true. A narrow interval indicates greater precision than a wide interval, while an interval spanning a range of clinically distinct possibilities may leave substantial uncertainty. These are general statistical principles. No confidence interval or between-arm estimate is reported for this outcome, so precision of the contrast cannot be assessed.

A hypothesis test can also be used to assess how compatible the data are with a specified null hypothesis under a statistical model. A p-value does not measure the size or clinical importance of an effect, and it is not a measure of the probability that the null hypothesis is true. No inferential test result is posted for the primary outcome. The registry record’s note that a two-arm comparison is not estimable for the continuous endpoint means it would be inappropriate to supply a comparison test as though it were the sponsor’s analysis.

Why can small outcome groups matter?

In general, estimates from smaller groups tend to be less precise, because fewer observations are available to characterize the group and its outcome variation. Randomization does not guarantee that the realized groups will be balanced on every characteristic. This is a general consideration, not a claim that a particular imbalance occurred in this study. The posted outcome counts are 9 and 12, but the record does not give a confidence interval, baseline comparison, or adjusted analysis that would help characterize uncertainty or account for measured prognostic factors.

Over-dispersion is a general issue in some statistical models when observed variability exceeds what the model assumes. It can lead to uncertainty estimates that are too small if the model does not accommodate the extra variation. The posted primary endpoint is continuous, and the registry record does not state that an over-dispersion model was used or that over-dispersion was assessed. It would therefore be speculative to attribute the reported dispersion values to a particular modeling choice. The relevant general lesson is that uncertainty estimates depend on whether the model’s assumptions represent the data.

What do planning illustrations mean?

Sample-size planning uses assumptions about the expected effect, variability, significance level, allocation, and desired power to illustrate how many participants might be needed for a future study. Such planning figures are not observed trial results and are not observed power. The registry record describes a planning illustration based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It states that the illustration is not the trial’s own design. The record does not report the trial’s sample-size justification or its original design assumptions. Because the two-arm continuous comparison is not estimable, the planning assumptions should not be treated as an independent confirmation of a treatment effect.

For a valid analysis, the statistical plan would also specify the outcome definition, analysis population, handling of missing observations, and any adjustments or sensitivity analyses. Those details are not reported in the registry record. The posted arm summaries can be described accurately, but the missing inferential and analysis details prevent a fuller assessment of how the trial’s primary question was evaluated.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("ARM 1: onaBoNT-A + Placebo", "ARM 2: Saline + Tamsulosin")
n   <- c(9, 12)
m   <- c(18.66, 14.16)
sp  <- c(0.07, 0.05)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  ARM 1: onaBoNT-A + Placebo  9  18.660  0.070  18.606  18.714
CARM  ARM 2: Saline + Tamsulosin  12  14.160  0.050  14.128  14.192

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome measure, the AUASS at 3 months, and no posted secondary outcomes. It reports no analyses. It does not describe whether other outcomes, time points, subgroup comparisons, or interim analyses were planned. The statistical plan, including any procedure for controlling multiplicity across tests, is not reported in the registry record. With no posted inferential results, there is no basis for assessing how multiple comparisons may have been handled.

Missing-data handling is also not described. The posted primary outcome counts are 9 for onaBoNT-A plus placebo and 12 for saline plus tamsulosin, while total enrollment is listed as 63. The record does not state how many participants were randomized overall, whether all randomized participants were assessed at 3 months, why outcome data are not listed for other enrolled participants, or how any unavailable values were treated. It does not report imputation, a complete-case rule, or a sensitivity analysis. These details should not be inferred from the group summaries.

The record identifies the primary outcome population as volunteers randomized to one of the two strategies, but it does not specify whether the reported analysis included everyone according to original assignment, only participants with observed outcomes, or another analysis set. The method used to handle deviations from assigned treatment is not reported in the registry record. Without these definitions, the population represented by the arm means is not fully clear.

These reporting gaps affect interpretation because missing observations and choices about analysis populations can influence the estimate and its uncertainty. They do not establish that any particular bias occurred. Rather, they mean that readers cannot determine from the record whether the missingness was related to treatment, outcome, or other factors, or whether the analysis tested the intended randomized comparison.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: unrelated (11.1%).

The registry record lists serious adverse events among 1 of 9 participants at risk in the onaBoNT-A plus placebo arm and 0 of 12 at risk in the saline plus tamsulosin arm. It reports 0 deaths in both groups. These are the posted counts, with the at-risk totals stated separately for each arm. They are safety summaries and should not be conflated with the primary symptom-score outcome.

The record also lists 1 participant with other, non-serious adverse events among 9 at risk in the onaBoNT-A arm, and 0 among 12 at risk in the saline plus tamsulosin arm. The top serious adverse event term is labeled Unrelated, with 11.1%. The registry does not give further event-level detail in the listed safety summary. In particular, it does not describe the event’s nature, timing, or relationship assessment beyond the term shown.

Adverse-event counts are descriptive. With these small at-risk groups, the counts do not by themselves provide a precise comparison of safety between strategies. A zero count does not establish that no risk exists, and a reported event does not by itself establish that treatment caused it. The registry record does not report a statistical comparison for adverse events or additional detail needed to assess differences in exposure or follow-up. The figures should therefore be read as the posted event counts, not as a complete comparative safety analysis.

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

The registry record establishes that this was a randomized Phase 2 study comparing onaBoNT-A injection plus oral placebo with saline injection plus tamsulosin. It posts arm-level AUASS summaries at 3 months, and defines higher scores as worse. Those details describe the design and the recorded outcome values, but they are not enough to establish the magnitude or precision of a treatment effect.

The posted means are 18.66 for onaBoNT-A plus placebo and 14.16 for saline plus tamsulosin. Because the record does not provide a valid estimable two-arm comparison, no inferential conclusion about the difference between the strategies can be drawn from these means alone. There is no reported confidence interval or test result. The record also does not explain the small outcome counts relative to enrollment or how missing outcomes were handled. This leaves uncertainty about which participants contributed to the summaries and how representative they are of the randomized groups.

The posted result does not show whether the groups differed at baseline, whether participants adhered to assigned treatment, or whether other aspects of care were balanced. The registry record does not report an adjusted analysis, sensitivity analysis, or detailed statistical plan. These omissions do not prove that the trial had biased results; they limit what can be established from the registry entry.

Nor should the arm means be treated as a direct statement about what an individual participant would experience. Group averages do not describe the full spread of individual responses, and the record does not provide individual data. The reported standard deviations are the only dispersion summaries and are not accompanied by distributions or clarification beyond the measure label.

The appropriate reading is therefore narrow: the registry record reports the specified design, arm-level outcome summaries, and selected adverse-event counts. It does not report the inferential analysis needed to quantify the primary between-group contrast, and it does not provide enough information to resolve missing-data or analysis-population questions. The results should not be presented as proof that either strategy is superior or equivalent.

14. Why This Trial Matters Statistically

This trial is statistically noteworthy because it pairs a randomized design with a registry result that does not report an estimable comparison for its continuous primary endpoint. Randomization is intended to support fair comparisons, but the value of that design for interpretation depends on transparent reporting of the analysis and its uncertainty. Arm-level means alone do not show how precisely the treatment contrast is estimated.

The outcome summaries list 9 participants in one arm and 12 in the other, compared with an enrollment figure of 63. The record does not explain the difference. This makes clear why participant flow and analysis-population definitions are not administrative details: they help readers understand which data underpin the estimates and whether the intended randomized comparison was preserved.

The record also illustrates the distinction between a trial’s planned enrollment and its outcome analysis. The trial summary describes planned recruitment of 74 volunteers, whereas enrollment is recorded as 63. Neither figure identifies the number with a posted primary outcome. A complete statistical report would explain how recruitment, randomization, follow-up, and analysis populations relate to one another.

Finally, the registry entry emphasizes that statistical interpretation relies on more than a point estimate. A confidence interval, analysis methods, missing-data information, and any multiplicity approach would help readers evaluate precision and robustness. Their absence does not erase the descriptive data, but it constrains the conclusions that can be drawn from them. For researchers, this is a practical example of why complete outcome reporting is essential for judging what a randomized trial can and cannot tell us.

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.

Several limitations specific to this registry record affect interpretation. First, the posted primary outcome counts are 9 and 12, while enrollment is 63 and the trial summary describes planned recruitment of 74. The record does not reconcile these figures or explain the participant flow from enrollment to the 3-month outcome. It is therefore unclear why the outcome summaries include those counts or what happened to participants without listed outcome values.

Second, the record does not report an estimable statistical comparison for the continuous primary endpoint. It gives means and standard deviations but no between-arm estimate, confidence interval, or test result. As a result, the precision of the primary comparison cannot be assessed. The posted standard deviations are 0.07 and 0.05; the registry identifies them as standard deviations but does not further explain their derivation or provide participant-level data to clarify the outcome distribution.

Third, the statistical analysis plan and analysis population are not reported in the registry record. The record does not describe whether all randomized participants were analyzed as assigned, how missing outcomes were handled, whether analyses were adjusted, or whether sensitivity analyses were performed. It also does not report a multiplicity plan or interim analyses. These omissions leave important aspects of the intended analysis unresolved.

Finally, masking is described as triple in the design fields and double-blind in the brief summary, with no explanation of the differing descriptions. The record does not provide details on random-sequence generation or concealment. These are reporting limitations, not evidence that specific procedures were or were not used. The posted safety counts are also limited summaries and do not include extensive event-level detail or a comparative analysis.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effectiveness of onaBoNT-A vs Oral Tamsulosin in Men With BPH and LUTS — NCT01589263.
• Registry record last updated 2021-10-05; status last verified 2021-09.
• Results first posted 2021-10-05.
• 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

NCT01589263 is a completed Phase 2 randomized parallel-group trial sponsored by the VA Office of Research and Development. It compares onaBoNT-A 200 U by prostate injection plus oral placebo with saline prostate injection plus tamsulosin 0.4 mg daily in male Veterans with BPH-associated lower urinary tract symptoms. The trial summary describes planned recruitment of 74 volunteers; the record lists enrollment of 63. The start date is 2012-06-01, and the primary completion date is 2019-09-30.

The primary endpoint is AUASS at 3 months, scored from 0 to 35, with higher values worse. The posted means are 18.66 among 9 participants in the onaBoNT-A arm and 14.16 among 12 participants in the saline plus tamsulosin arm. The record does not report an estimable two-arm comparison, confidence interval, or inferential test. It also does not explain the outcome counts, missing-data handling, or analysis population. Serious adverse events are listed for 1 of 9 and 0 of 12 participants, respectively, with no deaths reported in either group.