A Safety and Efficacy Study of Enzalutamide in Indian Patients With Progressive Metastatic Castration-Resistant Prostate Cancer (mCRPC) Previously Treated With Docetaxel-Based Chemotherapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Safety and Efficacy Study of Enzalutamide in Indian Patients With Progressive Metastatic Castration-Resistant Prostate Cancer (mCRPC) Previously Treated With Docetaxel-Based Chemotherapy (NCT03641560), a na phase 4 study. The primary outcome is Number of Participants With Treatment- Emergent Adverse Events (TEAEs).

2. Clinical Question

3. Trial Design

This was a multicenter, Phase 4, open-label, single-arm study of enzalutamide in Indian patients with progressive mCRPC previously treated with docetaxel-based chemotherapy. Its registry status is completed. The record gives a start date of 2018-09-19 and a primary completion date of 2024-02-20, and lists enrollment as 52. It does not report the number of participating centers or provide further details about the setting.

Participants in the enzalutamide group received 160 mg orally once daily, described as 4 capsules of 40 mg. Treatment was to continue until disease progression, unacceptable toxicity, or another discontinuation criterion. ADT is listed as an intervention, but the registry record does not specify a dosing regimen, timing, or how ADT was used alongside enzalutamide.

Because the study had a single group and no randomized comparator, its design can describe events observed during treatment but cannot isolate the effect of enzalutamide from the natural course of disease, prior treatment, other care, or other influences. Open-label status means masking was absent; the registry records masking as NONE. The record does not report a protocol-based rationale for the enrollment target, details of recruitment, or additional design features. It also does not describe a statistical analysis plan. These omissions limit what can be concluded about how the study was intended to analyze its outcomes.

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.

Before assignment: Eligible participants who met inclusion criteria and none of the exclusion criteria were enrolled.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: SAF

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: Safety Analysis Set (SAF): The SAF consisted of all participants who took at least 1 dose of study drug, and was used for safety analyses.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment- Emergent Adverse Events (TEAEs), measured over From first dose of study drug until 30 days after last dose (Up to 1899 days).

The primary outcome is the number of participants with treatment-emergent adverse events. The registry defines an adverse event as an untoward medical occurrence temporally associated with use of a medicinal product, whether or not considered related to that product. A TEAE is an adverse event observed after starting the study drug. Events could include symptoms, diseases, or unfavorable findings from laboratory or other safety assessments; the definition does not require that an event be judged caused by treatment.

The stated observation window begins with the first dose and ends 30 days after the last dose, with the timeframe described as up to 1899 days. Counting participants with at least one event is a way to describe how many people experienced an event during that window. It is different from counting the total number of events: a participant can experience more than one event, while a participant count records whether that person had an event.

Safety and tolerability are the stated focus for this primary outcome. Such a count provides a descriptive measure of observed events, but on its own does not establish whether treatment caused them or how the rate compares with another treatment. The numerical result for the primary outcome is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a participant-count primary outcome and lists no analyses. It does not report the statistical methods used to analyze the outcomes. The explanations below are general statistical context and should not be read as a description of an analysis performed in this study.

What does a participant count represent?

A count of participants with an event records how many people experienced at least one qualifying event over the specified observation window. This is not the same quantity as the total number of events. If a person has repeated events, a participant-level count still represents that person as affected; an event count can include repeated occurrences. The registry names the primary outcome as the number of participants with TEAEs, but does not report its numerical value.

To interpret a count as a proportion, a reader also needs to know the relevant denominator and how participants were included in the analysis. The adverse-event record gives at-risk fields for its group, but the registry record does not report a numerical result for the primary TEAE outcome or explain whether the outcome count uses the same denominator and analysis rules as those fields. It is therefore important not to infer a primary endpoint result from separate adverse-event entries.

How would uncertainty usually be described?

In general, an estimate is more informative when accompanied by a measure of uncertainty, such as a confidence interval. A confidence interval expresses the range of values reasonably compatible with the data and the statistical method, under its assumptions. It is not a guarantee that the true value lies within the interval. For a participant count or proportion, the appropriate interval depends on the precise outcome definition, denominator, and method. No confidence interval for the primary outcome is reported in the registry record.

For a single-group study, a proportion can describe the observed frequency in that group if the numerator and denominator are available. It does not by itself estimate a treatment effect relative to a comparator. A comparative effect requires a suitable comparison and a clear definition of the contrast. Neither a randomized comparator nor a comparative analysis is reported for this study.

Why do the analysis population and follow-up matter?

Analysis populations define which participants contribute to a particular result. The primary outcome is associated with the label SAF, but the registry record does not explain that label or describe exclusions, evaluability requirements, or participant flow. Follow-up also matters: the primary outcome window runs from the first dose to 30 days after the last dose, and the listed timeframe extends up to 1899 days. A longer observation period can create more opportunity to record an event; interpreting event frequency therefore requires understanding exposure and time under observation. The registry record does not provide participant-level follow-up or time-at-risk summaries.

Missing outcome information can affect interpretation when participants do not complete follow-up or when event status is unknown. General methods may address missingness through stated assumptions and sensitivity analyses, but those choices need to be reported to assess their implications. The registry record does not describe missing-data handling, completeness of outcome ascertainment, or sensitivity analyses for these outcomes.

What does the planning illustration mean?

The registry describes a planning illustration based on an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says that non-time-to-event illustrations express participants per arm, while time-to-event illustrations express total events. These are assumptions for planning calculations, not a description of the enrolled study: the trial itself is single-arm, and no randomized two-arm allocation is reported. The record does not give the effect used or the resulting planning values. The illustration is not observed power and does not show that the study had a particular probability of detecting an effect.

In general, power calculations depend on the effect size being targeted, outcome variability, significance level, allocation, and analysis method. If the effect used for planning is based on an observed result, that result and its uncertainty are important context. A planning calculation is not evidence that an effect was observed or that a trial's result is precise. Here, the record does not provide the numerical outcome result needed to assess the stated effect or reproduce the planning exercise.

What can be said about modeling?

The record does not describe a model, adjustment variables, confidence-interval method, hypothesis test, or approach to repeated events. For a binary participant outcome, general methods can estimate a proportion and its uncertainty. For recurrent event counts, methods may need to account for repeated events within a participant; over-dispersion matters generally when event counts vary more than a simple model assumes, because ignoring that variability can misstate uncertainty. Those possibilities are general methodological considerations, not evidence that any such model was used.

Without the analysis methods and numerical results, readers cannot assess model assumptions, covariate adjustment, or robustness of estimates. The record's stated design and endpoint definitions can be described, but statistical methods or inferential findings beyond those details are not reported in the registry record.

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("Enzalutamide")
n      <- c(52)
events <- c(36)
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  Enzalutamide  52  36  69.2  54.9  81.3  55.7  80.1  55.7  80.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures, including the primary TEAE outcome and a secondary outcome for the percentage of participants with a confirmed PSA response. It does not report numerical results for these outcomes, and it lists 0 analyses. A statistical plan describing which outcomes were tested, how they were prioritized, or how any tests were interpreted is not reported in the registry record.

Multiplicity is a general concern when several outcomes or hypotheses are examined: the chance of at least one apparently unusual result can depend on how many comparisons are made and how they are handled. Methods such as prespecifying a primary outcome or adjusting tests can address this, but the registry record does not report whether such methods were planned or used. No conclusion about multiplicity control can be drawn from the outcome list alone.

The primary analysis population is labeled SAF, but its definition is not reported. The record does not describe participant flow, exclusions from analysis, missing outcome data, or how incomplete follow-up was handled. It also does not report imputation, sensitivity analyses, or procedures for participants who discontinued treatment. These details matter because the observed outcome can depend on who is included and how unobserved outcomes are addressed. Their absence limits assessment of the completeness and potential bias of the reported safety and PSA findings.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: respiratory failure (3.8%), cardiac arrest (1.9%), cardio-respiratory arrest (1.9%), myocardial ischaemia (1.9%), asthenia (1.9%).

The enzalutamide adverse-event record lists 52 participants at risk in the serious-event field and 10 affected by serious events. The other-event field lists 52 at risk and 25 affected. The record also lists 6 deaths. These are descriptive entries for the single study group; they do not establish treatment causation, and the registry record does not explain whether the serious-event and other-event categories overlap.

The listed serious-event terms and percentages are respiratory failure (3.8%), cardiac arrest (1.9%), cardio-respiratory arrest (1.9%), myocardial ischaemia (1.9%), asthenia (1.9%), and chest discomfort (1.9%). The registry record does not report the denominator or calculation method for these term-specific percentages, nor does it give a comparative group. They should be read as registry-listed descriptive figures, not as comparative risks.

The primary endpoint is broader: it counts participants with TEAEs, defined as events observed after study-drug initiation. The serious and other adverse-event entries do not provide the missing numerical primary endpoint result. The record's adverse-event definition also does not require an event to be judged related to the medicinal product.

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

This study documents a Phase 4, open-label, single-arm evaluation of enzalutamide in Indian patients with progressive mCRPC previously treated with docetaxel-based chemotherapy. It specifies the intended safety outcome and describes evaluation of PSA, and the adverse-event record contains descriptive counts and listed serious-event terms. Those details help define what was studied and what kinds of observations were recorded.

The registry record does not report numerical results for the primary TEAE outcome or the confirmed PSA response outcome. It also lists 0 analyses. As a result, the record does not support a numerical estimate of the primary outcome, a confidence interval for that outcome, or a statistical estimate of PSA response. No comparative estimate is available from the single-group design.

Even when an event is recorded after treatment starts, timing alone does not prove that treatment caused it. The adverse-event definition explicitly includes events whether or not they are considered related to the medicinal product. Without a control group, the study cannot distinguish treatment-associated events from events that might occur due to disease, prior treatment, other care, or chance. This is a general limitation of interpreting uncontrolled safety observations.

The listed counts and serious-event terms should not be treated as a full account of clinical benefit or harm. The record does not supply the analysis details needed to evaluate missingness, follow-up completeness, uncertainty, or the basis for the term-specific percentages. Nor does the absence of a reported numerical outcome mean that no events or responses occurred. It means the registry record does not provide those outcome estimates.

Overall, the record describes the study's design, treatment approach, outcome definitions, and selected adverse-event information. It does not report enough statistical results to quantify the primary endpoint or PSA response, or to make a controlled comparison. Interpretation should remain limited to those documented descriptive details.

14. Why This Trial Matters Statistically

This study is statistically notable for the gap between a clearly stated safety question and the numerical results available in the registry record. The primary outcome is defined as the number of participants with TEAEs, and the registry describes a treatment window and an analysis population label. Yet the primary outcome's numerical result and the statistical analyses are not reported. Outcome definitions alone do not reveal the frequency or precision of an outcome.

The single-arm design is also central to interpretation. It can record safety events during treatment, but without a comparator it cannot estimate a treatment contrast. A descriptive count answers what was recorded in the treated group; it does not establish what would have happened under another treatment or without study treatment. This distinction is essential when reading adverse-event counts or considering the stated interest in PSA.

The registry also lists a confirmed PSA response outcome, but does not report its numerical result. That makes the difference between an outcome being named and an outcome being quantified especially important. A study can specify an endpoint without posting the estimate, uncertainty, or analysis needed to judge its observed result.

Finally, the planning illustration is described using assumptions for a two-arm calculation, whereas the actual study is single-arm. Planning scenarios can be useful for illustrating how assumptions relate to sample-size requirements, but they are not observed power and do not provide missing outcome evidence. In this record, the effect used and planning values are not reported. The key statistical lesson is to separate design, endpoint definition, descriptive safety entries, and inferential evidence rather than treating them as interchangeable.

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 absence of numerical primary and secondary outcome results is a major limitation for interpreting this registry record. Although the primary TEAE measure and confirmed PSA response outcome are identified, their results are not reported, and the record lists 0 analyses. This prevents assessment of the observed outcome estimates and their precision.

The study has no comparator arm, and the registry records a single-group model with allocation listed as NA. It therefore cannot provide a randomized treatment contrast. Open-label status, recorded as NONE for masking, also means the study was not masked; the record does not describe procedures to reduce the potential influence of unmasked assessment.

Important analysis details are not reported in the registry record. These include the statistical analysis plan, a definition of the SAF population label, missing-data handling, participant flow, outcome completeness, and methods for calculating uncertainty. The term-specific percentages are listed without a reported denominator or calculation method. The record also does not give further detail on how ADT was used alongside enzalutamide.

Finally, enrollment of 52 does not itself establish statistical precision or adequacy for the outcomes. The record does not report a sample-size justification, and its planning illustration's effect and resulting values are not available. These limitations restrict interpretation to the design and descriptive entries that are explicitly recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Safety and Efficacy Study of Enzalutamide in Indian Patients With Progressive Metastatic Castration-Resistant Prostate Cancer (mCRPC) Previously Treated With Docetaxel-Based Chemotherapy — NCT03641560.
• Registry record last updated 2026-06-24; status last verified 2026-05.
• Results first posted 2025-01-23.
• 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, multicenter, Phase 4, open-label, single-arm study of enzalutamide in Indian patients with progressive mCRPC previously treated with docetaxel-based chemotherapy. Enrollment was 52. The recorded start date is 2018-09-19, and the primary completion date is 2024-02-20.

Participants received enzalutamide 160 mg orally once daily, described as 4 capsules of 40 mg, until progression, unacceptable toxicity, or another discontinuation criterion. The primary outcome was the number of participants with TEAEs; a secondary outcome was confirmed PSA response. Numerical results for these outcomes are not reported in the registry record, which lists 0 analyses.

The adverse-event record lists 10 participants affected by serious events, 25 by other events, and 6 deaths, with 52 at risk in each event field. These are descriptive registry entries, not comparative or causal estimates.