Docetaxel and Carboplatin in Treating Patients With Metastatic, Castration Resistant Prostate Cancer Containing Inactivated Genes in the BRCA 1/2 Pathway: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Docetaxel and Carboplatin in Treating Patients With Metastatic, Castration Resistant Prostate Cancer Containing Inactivated Genes in the BRCA 1/2 Pathway (NCT02598895), a na phase 2 study. The primary outcome is Proportion of Patients With PSA Decline by 50% From Baseline.

2. Clinical Question

The clinical question is therefore about the observed frequency of a specified PSA response in a selected group receiving the combination. It is not a direct comparison of the regimen with another treatment, and it cannot by itself distinguish changes associated with treatment from changes that might occur for other reasons. The study is identified as a pilot clinical trial, and the recorded enrollment is 14. Its focus is a biologically defined population: patients with metastatic, castration-resistant prostate cancer and inactivated genes in the BRCA 1/2 pathway. The registry’s condition list also includes metastatic prostate carcinoma, bone metastasis, PSA progression, and stage IV prostate cancer.

The primary question concerns PSA decline, not survival, symptom relief, or another direct measure of how patients feel or function. Although the record describes treatment continuing until disease progression or unacceptable toxicity, that wording does not make progression or toxicity the primary endpoint. The primary endpoint is specifically the proportion meeting the PSA-decline criterion during the stated assessment period.

3. Trial Design

This is a Phase 2, completed, single-group pilot trial sponsored by the University of Washington. The registry reports enrollment of 14 and lists the allocation as not applicable, the model as single group, and masking as none. These design features matter for interpretation: all participants are assigned to the treatment group described in the record, and no concurrent control group is available for a direct comparison.

The treatment group is described as receiving docetaxel and carboplatin. Both drugs are administered intravenously over 30-60 minutes on day 1. Treatment repeats every 21 days for 10 courses unless disease progression or unacceptable toxicity occurs. Laboratory biomarker analysis is also listed among the interventions. The registry does not report whether all enrolled participants received every planned course, nor does it give a participant-flow account or reasons for any treatment discontinuation.

The study started on 2016-01-26, reached primary completion on 2021-09-14, and is marked completed. The primary outcome timeframe is described as extending until disease progression or unacceptable toxicity, with assessment up to 35 days after the last dose of study medication. This timeframe defines when the endpoint could be assessed; it does not establish how many participants had evaluable PSA measurements or when each participant’s final assessment occurred.

The registry records one outcome measure and one analysis. It does not report a separate control arm, randomization procedure, blinding, or a comparative treatment estimate. Details of the planned sample-size justification, the intended statistical analysis plan, and any interim analyses are not reported in the registry record. Consequently, the design can be described as a small, single-group evaluation of a specified combination and endpoint, but the registry record does not establish how the enrollment target was selected or whether the final analysis followed a prespecified plan.

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: Patients treated with docetaxel and carboplatin.

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 Proportion of Patients With PSA Decline by 50% From Baseline, measured over Until disease progression or unacceptable toxicity, assessed up to 35 days after the last dose of study medication.

The primary endpoint is the proportion of treated patients whose prostate-specific antigen (PSA) declines by 50% from baseline, using Prostate Cancer Working Group 2 (PCWG2) criteria. The registry describes the outcome as a participant count and identifies the population as patients treated with docetaxel and carboplatin. The assessment timeframe is until disease progression or unacceptable toxicity, assessed up to 35 days after the last dose of study medication.

In general, a proportion expresses how often a defined event occurs within a specified group. For this endpoint, the event is meeting the PSA-decline threshold. It is a binary outcome for each participant: the individual either meets the stated criterion or does not. A response proportion can provide a concise description of biological activity in the population studied, while a clear criterion helps make the event definition reproducible.

PSA is a biomarker, so this endpoint measures a laboratory change rather than directly measuring survival, symptoms, or daily functioning. A PSA decline does not, by itself, answer whether patients live longer or feel better. Nor does the endpoint definition establish a causal effect of treatment in the absence of a comparison group. The registry record does not report the observed number meeting the criterion, the denominator used in the endpoint analysis, or an estimate of the response proportion. The primary endpoint result is therefore not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a binary primary outcome: whether each treated participant had a PSA decline of 50% from baseline according to PCWG2 criteria. The outcome is expressed as a participant count, and the stated population is patients treated with docetaxel and carboplatin. The registry record does not report the observed count or endpoint estimate. The concepts below explain how such an outcome is ordinarily interpreted; they do not fill in the missing result.

What does a binary endpoint measure?

In general, a binary endpoint classifies each participant according to whether a predefined event occurred. Here the event is reaching the stated PSA-decline criterion. The number of participants meeting the criterion is the numerator; the number included in the endpoint analysis is the denominator. Dividing the numerator by the denominator gives an observed proportion. Because neither endpoint count nor analysis denominator is reported in the registry record, that proportion cannot be stated from the record.

A clearly specified threshold makes the endpoint easier to apply consistently, but interpretation also depends on measurement procedures and analysis rules. The record names PCWG2 criteria and gives the assessment period, but does not report details such as the schedule of PSA measurements, how baseline was selected, how confirmation of a decline was handled, or how missing measurements were treated. Those details are not reported in the registry record and should not be assumed.

How should uncertainty be understood?

In general, a confidence interval describes a range of values compatible with the observed data under a statistical model. It conveys uncertainty in an estimate; it does not ensure that the true value lies within the interval, and it does not address every possible source of bias. For a response proportion, interval width depends in part on the amount of information available and the observed response frequency. A small study can yield imprecise estimates, so the point estimate alone would not be enough to understand precision. No confidence interval for the primary endpoint is reported in the registry record.

A p-value, when reported, addresses how compatible the data are with a specified null model under the assumptions used for the test. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry record does not report a primary-endpoint p-value or the hypothesis test used. In this single-group study, a test against a benchmark would require a stated benchmark and a prespecified analysis; neither is reported in the registry record.

What does over-dispersion mean for this outcome?

In general, over-dispersion occurs when observed variability exceeds what a statistical model expects. For binary outcomes, this can arise when participant outcomes are more alike within subgroups, or more variable across subgroups, than a simple model allows. Ignoring extra variability can make uncertainty estimates too narrow. Whether over-dispersion is relevant depends on the analysis model and data structure. The registry record does not describe a model for the primary endpoint, so it is not possible to determine whether over-dispersion was assessed or how it might affect inference.

How does the design affect inference?

The study has a single treatment group, allocation is listed as not applicable, and masking is listed as none. In general, a single-group outcome can describe the experience of participants receiving the regimen, but it lacks a concurrent control for separating treatment effects from other influences. Changes over time, participant selection, measurement practices, and other care can affect observed outcomes. A randomized comparator can help address some of these issues; this trial does not include one according to the registry record.

The record identifies the study as Phase 2 and reports enrollment of 14. It does not report the rationale for that enrollment, a formal sample-size justification, or the intended power for the primary endpoint. The planning illustration described alongside the trial uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. Those are planning assumptions, not a description of this single-group design, and the illustration is not observed power. Sample-size calculations under hypothetical assumptions do not establish what the trial was designed to detect unless the assumptions and analysis plan match the trial’s actual design.

In general, normal approximations may be less reliable when event counts are sparse. For a binary endpoint in a small study, alternative methods may be considered depending on the analysis objective and model. The registry record does not identify the method used for the primary endpoint, so no particular estimation or testing procedure can be attributed to this trial.

What information would support a fuller assessment?

A complete statistical interpretation would need the endpoint numerator and denominator, the response estimate, a measure of uncertainty, and a clear account of the analysis population and missing observations. It would also need the prespecified statistical plan, including any inferential test, adjustments, and handling of protocol deviations. These details are not reported in the registry record. Accordingly, the endpoint definition can be explained, but its observed magnitude and statistical precision cannot be assessed from the record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure and one analysis. It does not describe whether additional endpoints were analyzed outside those entries, whether the primary endpoint was selected from a broader set, or whether multiplicity was considered. The planned hierarchy of outcomes and any adjustment for multiple testing are not reported in the registry record. Without those details, it is not possible to assess whether the reported endpoint was the sole prespecified inferential focus or how any multiplicity would affect interpretation.

The record does not report the primary endpoint result, the analysis denominator, or how participants without an evaluable PSA assessment were handled. It does not describe imputation, exclusion rules, treatment of early discontinuation, or sensitivity analyses for missing data. These choices can affect a binary response proportion because the result depends on which participants are included and how unevaluable cases are classified. No missing-data method should be inferred from the endpoint definition alone.

The endpoint population is described as patients treated with docetaxel and carboplatin, while enrollment is reported as 14. The registry does not clarify whether the primary analysis included all enrolled participants, only those who received treatment, or a different analysis population. It also does not provide a participant flow accounting for treatment initiation, completion, or endpoint availability. The analysis population and missing-data handling are therefore not reported in the registry record.

The registry’s single-group design makes the choice of analysis population important for describing the treated cohort, but it does not provide a control group for comparative inference. The statistical analysis plan, including any interim analyses and any prespecified multiplicity approach, is not reported in the registry record.

11. 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 non-serious adverse event terms

The registry lists safety counts for the treatment group, with 14 participants at risk for serious adverse events and 0 affected. For other adverse events, it lists 14 at risk and 5 affected. It also reports 10 deaths. These are distinct entries in the record and should not be combined into a single measure or interpreted as if they shared the same definition.

The serious adverse event count indicates that no participants are listed as affected in that category in this registry entry. The record does not provide serious-event terms, and its list of top serious terms is empty. The other-adverse-event count is a participant count, not a count of individual events; the record does not identify the terms or severity details for those cases. It also does not explain the death count’s causes, timing, or relationship to study treatment. The record does not state whether the deaths were considered treatment-related.

These safety figures should be read as registry-reported counts for this study group, not as a complete account of every possible event or as a comparison with another treatment. With no control group, the figures cannot establish relative risk. The registry record does not report additional context needed to interpret exposure duration, event ascertainment, or attribution.

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

The trial is a completed Phase 2, single-group study of docetaxel and carboplatin in patients with metastatic, castration-resistant prostate cancer and inactivated genes in the BRCA 1/2 pathway. Its primary endpoint is a PSA decline of 50% from baseline according to PCWG2 criteria, assessed during the stated period. The registry record does not report the observed endpoint result, so it does not establish how many treated participants met the criterion or how precise an estimated response proportion would be.

Even if a response proportion were available, its interpretation would be descriptive in this design. In general, outcomes observed in a treatment group do not by themselves demonstrate that the treatment caused those outcomes. Without a concurrent comparator, the trial cannot directly estimate the difference between the regimen and another treatment or usual care. The record therefore supports describing the study question and design, but not a comparative treatment effect.

The endpoint is a biomarker response. It does not directly report survival, symptoms, quality of life, or functional status. A biomarker outcome can be informative for a study’s stated objective, but it should not be treated as interchangeable with those other outcomes. The registry record does not report results for those outcomes.

The study’s enrollment of 14 and its selected population also limit how broadly any finding could be applied. The record does not report the endpoint denominator or participant characteristics in enough detail to assess how representative the analyzed group was. The safety entries—0 participants affected by serious adverse events, 5 affected by other adverse events, and 10 deaths—also lack event descriptions, attribution, and timing in the registry record. They should not be interpreted as establishing the cause of any death or the comparative safety of the regimen.

In short, the record identifies a clinically focused pilot study and defines its main response measure, but does not report the primary response result. It cannot support a claim about the magnitude, precision, or comparative meaning of that endpoint.

13. Why This Trial Matters Statistically

This trial illustrates why statistical interpretation starts with the design and endpoint, not just the treatment names. The registry describes a single-group Phase 2 pilot study with enrollment of 14 and a binary PSA-response endpoint. That structure makes the intended descriptive question clear: how often did treated participants meet a defined biomarker criterion? At the same time, the absence of a concurrent control limits causal and comparative conclusions.

It also highlights the difference between defining an outcome and reporting its result. The endpoint is described with a specific threshold, criteria, population, and assessment timeframe. Yet the registry record does not report the event count, analysis denominator, or estimated proportion. Without those elements, readers cannot assess the observed response or its precision. A well-specified endpoint is necessary for interpretation, but it cannot replace the result itself.

The trial also shows why planning calculations need to be distinguished from evidence observed in a study. The described sample-size illustration uses assumptions for a two-arm planning scenario, while the registered trial is single-group. Such an illustration can help explore hypothetical planning choices, but it is not a reconstruction of the trial’s design, nor is it observed power. A sample-size calculation does not compensate for absent outcome data or a missing analysis plan.

Finally, the safety counts demonstrate the need to retain context around registry entries. Serious adverse events, other adverse events, and deaths are reported as separate counts, but the record does not describe event terms, cause, or attribution. Statistical reading requires attention to what each count measures and to what the record leaves unspecified. This study is therefore useful for illustrating how design, endpoint definition, reporting completeness, and uncertainty jointly shape what can responsibly be concluded.

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 most consequential limitation in interpreting this registry entry is that the primary endpoint result is not reported in the registry record. Although the endpoint definition and timeframe are available, the record does not give the number of participants with a 50% PSA decline, the denominator analyzed, or an estimated proportion. It also does not report an uncertainty interval. The response magnitude and precision therefore cannot be evaluated.

The single-group design has no concurrent comparator. As a result, the record cannot provide a randomized comparison or establish how the observed course would differ under another treatment. Masking is listed as none, and allocation is listed as not applicable. The entry does not describe endpoint-assessment safeguards or procedures that might reduce assessment bias.

Enrollment is reported as 14, but the record does not provide a participant flow account, a detailed analysis population, or the number with evaluable PSA assessments. It does not describe missing-data rules, reasons for discontinuation, protocol deviations, or sensitivity analyses. The endpoint timeframe allows assessment until disease progression or unacceptable toxicity and up to 35 days after the last dose, but participant-level assessment timing is not reported.

The registry does not report the statistical analysis plan, the method used to estimate or test the response proportion, the sample-size justification, or any interim analyses. Although a planning illustration is described, its assumptions do not document the trial’s own design. The record also does not provide detailed baseline characteristics or results for additional clinical outcomes, limiting assessment of generalizability and the broader clinical context.

Safety interpretation is constrained by the lack of event terms and attribution. The record lists 0 participants affected by serious adverse events, 5 affected by other adverse events, and 10 deaths, but does not report causes, timing, or relationships to study treatment. These limitations are specific to the available registry information and should not be filled by assumptions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Docetaxel and Carboplatin in Treating Patients With Metastatic, Castration Resistant Prostate Cancer Containing Inactivated Genes in the BRCA 1/2 Pathway — NCT02598895.
• Registry record last updated 2022-11-17; status last verified 2022-10.
• Results first posted 2022-11-17.
• 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

The registry record identifies NCT02598895 as a completed Phase 2, single-group pilot trial sponsored by the University of Washington. It reports enrollment of 14 and studies docetaxel and carboplatin in patients with metastatic, castration-resistant prostate cancer containing inactivated genes in the BRCA 1/2 pathway. The treatment description specifies intravenous dosing on day 1, repeated every 21 days for 10 courses unless progression or unacceptable toxicity occurs.

The primary endpoint is the proportion of treated participants with a PSA decline of 50% from baseline according to PCWG2 criteria, assessed until progression or unacceptable toxicity and up to 35 days after the last dose. The endpoint result is not reported in the registry record. Safety entries list 0 participants affected by serious adverse events, 5 affected by other adverse events, and 10 deaths; event details and attribution are not reported. The record does not provide a control-group comparison, analysis denominator, missing-data approach, or statistical analysis plan.