Trial of NanoPac Focal Therapy for Prostate Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trial of NanoPac Focal Therapy for Prostate Cancer (NCT04221828), a na phase 2 study. The primary outcome is Number of Participants With Treatment Emergent Adverse Events.

2. Clinical Question

3. Trial Design

This was a Phase 2, single-group study of NanoPac focal therapy for prostate cancer in subjects undergoing radical prostatectomy. The registry lists an enrollment of 1, an allocation of not applicable, and no masking. With no comparator group, the study design can describe what was recorded for the participant treated, but cannot estimate a difference between treatment groups.

The intervention description specifies direct injection into the prostate cancer lesion at 15 mg/mL. The volume was not to exceed the volume of the lesion and was capped at 10% of total prostate volume. NanoPac could be administered on up to three occasions, with at least 28 days between each dose. These are registry descriptions of the planned administration, not evidence that every permitted dose was received.

The registry lists a start date of 2020-10-20 and a primary completion date of 2021-01-27. The study status is terminated. The reason for termination is not reported in the registry record, so the status alone does not explain why the study ended or whether the planned procedures and follow-up were completed.

The primary outcome was the number of participants with treatment-emergent adverse events during Day 1 to Day 85. Secondary outcomes covered histologic assessment, adenocarcinoma in sampled tissue, invasion into surrounding tissues, imaging measures, PSA density, lymph-node tumor presence, and paclitaxel concentration in systemic circulation. These descriptions identify what the study intended to assess; they do not establish that results for those outcomes were collected or reported.

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

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 Treatment Emergent Adverse Events, measured over Day 1 to Day 85.

The primary endpoint counts participants with at least one treatment-emergent adverse event during Day 1 to Day 85. The registry description includes events reflected in laboratory assessments, physical examination findings, and vital signs. This is a participant count rather than a count of every event episode: a participant is counted as having an event if an event meeting the endpoint definition is recorded.

In general, a safety endpoint of this kind is used to describe the occurrence of unwanted health events during a defined observation period after treatment. The time window helps specify which events belong to the endpoint, while the definition identifies the types of findings to include. The endpoint can be useful for organizing safety observations, but its meaning depends on how events were identified, classified, and recorded.

The registry record lists this endpoint but does not report a primary-outcome analysis or a detailed result for the full endpoint definition. Its adverse-event summary lists 1 participant at risk and 0 participants affected for serious events, and 1 at risk and 0 affected for other events. Those categories should not be assumed to provide a complete account of every component of the primary endpoint. The registry record does not report additional detail linking the counts to the endpoint’s laboratory, examination, and vital-sign components.

With enrollment of 1 and no comparator, the endpoint cannot support a reliable comparative estimate. The posted counts describe the record’s event categories for the participant at risk; they do not establish how frequently such events would occur in a broader population.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

For a binary safety outcome, each participant is classified according to whether an event occurred during the specified period. The resulting count is the number of participants with an event, not necessarily the number of separate events. This distinction matters because one participant may experience more than one event, while a participant-based endpoint still counts that person once. The registry labels the primary outcome as a count of participants.

General: a count is easiest to interpret alongside the number of participants who were observed and the rules used to define an event. A count of 0 in a small group says that no event was recorded in that group; it does not establish that the event could not occur in a larger group. Greater precision generally requires more observations and clear information about follow-up and ascertainment.

What does the study design allow?

The registry identifies a single-group design with no allocation to a comparator and no masking. General: an unblinded, uncontrolled study can report events observed among participants receiving the intervention, but cannot isolate the intervention’s contribution to those events. Without a control group, there is no within-study contrast to estimate a treatment difference. The study’s enrollment of 1 further limits how much variation in outcomes can be characterized.

No statistical analyses are listed in the registry record. It therefore does not report an inferential procedure for the primary endpoint, a model-based estimate, a p-value, or a confidence interval. General: a confidence interval expresses uncertainty around an estimated quantity; it is not a guarantee that the true value lies within its endpoints. No such interval is reported for these outcomes, so the posted counts should not be interpreted as precise estimates.

How should the planning illustrations be understood?

The registry’s sample-size assumptions describe a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The assumed effect is a stated fraction of the observed effect. For time-to-event outcomes, the planning quantity is a total number of events; for other outcomes, it is participants per arm.

General: a planning calculation asks how much information a hypothetical design might require under stated assumptions. It is not a measure of what the study actually observed, and it is not observed power. The registry explicitly describes the illustration as separate from the trial’s own design. That distinction is especially important for this single-group study, which does not have the two-arm allocation assumed in the illustration. No calculated planning values or observed-effect estimate are reported in the registry record, so those quantities cannot be interpreted from the information recorded.

Why does over-dispersion matter in general?

General: over-dispersion occurs when outcome variability is greater than a statistical model expects. If a model assumes less variability than is present, its uncertainty estimates may be too narrow and its tests may be misleading. The registry record does not report an over-dispersion assessment or a model for the outcomes, and no such adjustment should be inferred.

What can be said about the posted event counts?

The adverse-event summary separates serious events from other events and reports the number at risk and affected in each category. It lists 1 at risk and 0 affected in each category, with 0 deaths. These are descriptive counts. The registry does not report an analysis that estimates event probabilities or compares categories. General: a zero count is not equivalent to proof of zero risk, particularly when the number observed is small. It is also important not to confuse the absence of a reported analysis with evidence that a particular statistical method was used.

The registry lists secondary outcome descriptions, but not statistical analyses of those measures. There is no reported model, adjustment strategy, or inferential procedure for the histologic, imaging, laboratory, or other secondary measures. Accordingly, interpretation should stay with the endpoint definitions and counts actually recorded, and should not attribute unreported statistical methods or conclusions to the study.

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("NanoPac")
n      <- c(1)
events <- c(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  NanoPac  1  0  0.0  0.0  97.5  0.0  79.3  1.3  84.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary safety outcome and secondary outcomes covering several types of tumor assessment, imaging, laboratory measures, lymph-node involvement, and systemic drug concentration. When many outcomes are examined, general statistical practice recognizes a possibility that some apparent findings may arise by chance. A prespecified approach to handling multiple comparisons can help explain how such findings should be interpreted. The registry record does not report a multiplicity strategy, and it lists no statistical analyses.

Missing-data methods, the number of participants with data for each outcome, and rules for handling incomplete observations are not reported in the registry record. The enrollment is 1, but that alone does not establish whether all planned assessments were completed or whether any measurements were unavailable. The reason for termination and the completeness of outcome follow-up are also not reported. It is therefore not possible to determine whether missing observations affected the posted results.

The registry record does not define an analysis population, such as a population based on treatment received or eligibility for a particular assessment. It also does not report whether the primary endpoint was analyzed in all enrolled participants or in a subset. No assumptions about these choices should be inferred from the presence of an outcome definition or adverse-event counts.

With no analysis plan or reported analysis in the registry record, there is no basis for assessing how multiplicity, missing observations, or analysis-population decisions were addressed. The listed outcomes describe the planned areas of assessment, but do not substitute for reporting the methods used to analyze them.

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.

The registry’s adverse-event summary lists the NanoPac group with 1 participant at risk for serious events and 0 affected. For other adverse events, it also lists 1 at risk and 0 affected. The summary lists 0 deaths. No serious adverse-event terms are listed.

These are counts, not comparative estimates. The single-group design has no control arm, so the record cannot estimate whether the event counts differ from what would have occurred under another treatment or without treatment. The small number at risk also means the counts give limited information about the range of possible safety outcomes in a wider population.

The primary endpoint covers treatment-emergent adverse events from Day 1 to Day 85, including laboratory, physical examination, and vital-sign changes. The adverse-event summary is not accompanied by detailed results for every component of that endpoint. The registry record does not report enough detail to conclude that the summary exhaustively represents all events considered under the primary endpoint definition. The counts should therefore be read as the safety categories recorded, not as evidence that no adverse events of any kind could occur.

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

The record establishes that the study was a Phase 2 evaluation of NanoPac focal therapy, with enrollment of 1, a single-group design, and terminated status. It also records safety counts of 0 affected participants in the serious and other adverse-event categories, with 0 deaths. These findings describe the registry entries; they do not establish the frequency of events in a larger population.

The record does not establish whether NanoPac changed tumor characteristics or imaging findings. Although secondary outcomes address histology, tumor invasion, image volume, PSA density, PI-RADS score, lymph-node tumor presence, and systemic paclitaxel concentration, their results are not reported in the registry record. No estimate of treatment effect or statistical analysis is listed.

Because the study had no comparator, any observed change could not be separated from other explanations using a randomized within-study contrast. Because only 1 participant was enrolled, the record also provides little information about variation between people. The safety counts should not be read as proof that events are absent, and the listed treatment goals should not be read as evidence of clinical benefit.

The trial status and dates provide context for the study’s conduct, but the reason for termination and the completeness of planned follow-up are not reported in the registry record. Without those details or outcome analyses, the available information supports only a narrow descriptive account. It does not support a conclusion about comparative safety, efficacy, or how the findings would generalize to other people with prostate cancer.

14. Why This Trial Matters Statistically

This study illustrates how a registry entry can define a clinically relevant question while providing too little outcome information for a statistical conclusion. The primary endpoint focuses on treatment-emergent adverse events, and the listed secondary outcomes span tissue assessment, imaging, laboratory measures, and drug concentration. Those measures could describe different aspects of treatment exposure and response, but their results are not reported in the registry record.

The design is central to interpretation. A single-group study with no masking and enrollment of 1 can record what happened to the participant, but cannot provide a controlled estimate of what would have happened under an alternative. The posted adverse-event counts are informative as registry entries, yet their small denominator limits precision and generalizability.

The record also distinguishes outcome definitions from outcome analyses. Naming an endpoint does not show that data were collected, analyzed, or reported for it. Here, no statistical analyses are listed, and the reason for termination and completeness of follow-up are not reported. Those omissions prevent readers from assessing uncertainty, multiplicity, or the handling of missing data.

For clinical researchers and biostatisticians, the key lesson is to keep claims aligned with the design and the reported evidence. Descriptive counts can be stated as counts; they should not be converted into comparative conclusions when no comparator or analysis is reported. The registry entry is useful for understanding the intervention and intended assessments, while also showing why complete outcome reporting is necessary for interpretation.

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 most immediate limitation is enrollment of 1. This leaves little basis for characterizing variation in safety or tumor-related outcomes, and the registry’s adverse-event counts cannot provide a precise estimate for a broader population. The single-group design also lacks a comparator, so it cannot estimate a treatment contrast or separate intervention effects from other influences.

The registry lists the study as terminated, but the reason for termination is not reported in the registry record. It also does not report whether the planned dosing schedule was completed, whether Day 1 to Day 85 follow-up was complete, or whether all planned endpoint assessments were obtained. These uncertainties constrain interpretation of both the safety summary and the unreported secondary outcomes.

There are no statistical analyses listed. The registry does not report confidence intervals, tests, adjustment methods, multiplicity handling, missing-data procedures, or analysis populations. It does not provide results for the listed tumor-response, imaging, laboratory, or systemic concentration outcomes. The primary endpoint definition is available, but a complete result and analysis for that endpoint are not reported in the registry record.

The adverse-event summary lists 0 affected participants in its serious and other categories, but the record does not provide enough detail to treat those counts as a complete account of all events covered by the primary endpoint. The planning assumptions describe a hypothetical two-arm calculation rather than the actual single-group design; no calculated planning values are reported in the registry record. Together, these limitations mean the posted information is descriptive and insufficient for comparative or generalizable conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Trial of NanoPac Focal Therapy for Prostate Cancer — NCT04221828.
• Registry record last updated 2022-03-29; status last verified 2022-03.
• Results first posted 2022-03-29.
• 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 Phase 2, single-group trial of NanoPac focal therapy for prostate cancer in subjects undergoing radical prostatectomy. The intervention was direct injection of NanoPac into the prostate lesion, with the described concentration and administration limits recorded in the study entry. Enrollment was 1; allocation was not applicable and masking was none.

The primary endpoint was the number of participants with treatment-emergent adverse events from Day 1 to Day 85. The adverse-event summary lists 1 participant at risk and 0 affected in both the serious and other categories, with 0 deaths. The study is listed as terminated, and no statistical analyses are listed.

Secondary outcomes include histologic, imaging, laboratory, lymph-node, and systemic drug concentration measures. Their results, the reason for termination, and details about missing data or analysis populations are not reported in the registry record. The entry supports a limited descriptive reading, not a comparative treatment-effect conclusion.