This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Indwelling Pleural Catheter With Either Doxycycline or Saline at Day 7 for Pleurodesis (NCT02623959), a randomized phase 4 study. The primary outcome is The Primary Outcomes of Interest Will be Time to Catheter Removal..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02623959 |
| Phase | Phase 4 |
| Condition | Advanced Cancers, Malignant Pleural Effusions |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | M.D. Anderson Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
The record identifies advanced cancers and malignant pleural effusions as the conditions of interest. It does not report detailed eligibility criteria, participant characteristics, or a target population description beyond these conditions. Although the registry lists enrollment as 3, the primary outcome record states that no data were collected.
Intervention
The intervention arm was an indwelling pleural catheter (IPC) combined with doxycycline. The record also lists symptom and quality-of-life questionnaires, a fentanyl patch, intravenous fentanyl, and phone calls among the interventions. The arm description says questionnaires were completed at baseline and 10 - 14 days after receiving doxycycline.
Comparator
The comparison arm was an IPC combined with saline, described in the study summary as the current standard of care. Its arm description specifies questionnaires at baseline and 10 - 14 days after receiving saline. The descriptions also refer to a fentanyl patch and intravenous fentanyl around catheter drainage.
Primary question
The registered primary outcome was time to catheter removal over 1 month. The study planned to document the reason for removal, including decreased drainage, complications, or other reasons. The intended analysis was a cause-specific hazard Cox model with treatment group as a covariate. No outcome data or analysis were produced.
3. Trial Design
The registry describes a Phase 4, randomized, double-blind, parallel-group trial sponsored by M.D. Anderson Cancer Center. The registered comparison was an indwelling pleural catheter combined with saline versus an indwelling pleural catheter combined with doxycycline for treatment of malignant pleural effusions. The brief summary calls saline the current standard of care. The official title refers to indwelling pleural catheters versus indwelling pleural catheters plus doxycycline, while the listed arm descriptions identify the actual comparison as IPC plus saline versus IPC plus doxycycline.
The record lists enrollment as 3. It gives a study start date of 2016-04-27 and a primary completion date of 2017-05-23, and records the status as terminated. The primary outcome description explains that the protocol was terminated due to slow accrual and the design of the study. It also explicitly states that no data were collected and no analysis was done. The dates and listed enrollment do not establish that outcome data were available.
Questionnaires on symptoms and quality of life were planned at baseline and at 10 - 14 days after receiving the assigned treatment. The arm descriptions also refer to a fentanyl patch, a follow-up visit 5 days after IPC placement, intravenous fentanyl before catheter drainage, and catheter drainage. The descriptions end mid-sentence, so further details are not reported in the registry record. Specific randomization procedures, concealment methods, and details of how masking was maintained are not reported in the registry record.
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
| Stage | Indwelling Pleural Catheters (Randomized to Saline) | Indwelling Pleural Catheters+Doxycycline (Randomized to Rx Arm |
|---|---|---|
| STARTED | 0 | 1 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 0 | 1 |
Reasons for not completing this period:
| Reason | Indwelling Pleural Catheters (Randomized to Saline) | Indwelling Pleural Catheters+Doxycycline (Randomized to Rx Arm |
|---|---|---|
| Progression | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Due to slow accrual and the design of the study the protocol was terminated. No data was collected and no analysis was done.
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: 2 participants withdrew before randomization
| Characteristic | Unit | Indwelling Pleural Catheters (IPC) (Randomized to Saline) | IPC Plus Doxycycline (Randomized to Rx Arm) | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 1 | 1 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 1 | 1 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 0 | 1 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as The Primary Outcomes of Interest Will be Time to Catheter Removal., measured over 1 month.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was time to catheter removal, with a timeframe of 1 month. In general, a time-to-event endpoint measures how long it takes for a defined event to occur after a specified starting point. Here, the event was catheter removal. The record says the cause of removal would be documented and identifies decreased drainage, complications, and other reasons as categories for analysis.
Time to removal can capture both whether removal occurs and when it occurs, rather than reducing the outcome to a yes-or-no status at a single time. In general, the time component is useful when participants may experience the event at different times or may not experience it during the observation period. This kind of endpoint also requires clear definitions of the event, start time, follow-up period, and handling of participants whose event status is not observed. Those additional operational details are not reported in the registry record.
The planned cause-specific hazard Cox model reflects the stated interest in removal classified by cause. The registry record does not report any observed removal times, causes of removal, treatment effect estimate, or analysis. It therefore provides no trial result for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a planned comparison, not an estimate of treatment effect. It says the study was terminated because of slow accrual and the design of the study, and it states that no data were collected and no analysis was done. Consequently, there is no reported comparison of time to catheter removal between the saline and doxycycline groups. The record does not establish whether either group had earlier or later removals, or whether the reasons for removal differed.
The enrollment field lists 3, but the primary outcome population statement says no data were collected. These entries should be read together rather than treating the enrollment field as evidence of analyzable outcome observations. The record does not explain the relationship between the enrollment entry and the statement about data collection. It supplies no participant-level follow-up, event counts, censoring information, estimates, confidence intervals, or p-values.
The adverse-event group fields contain zeros, but the outcome record's statement that no data were collected means those entries cannot be interpreted as evidence that no adverse events occurred. No safety analysis or event assessment is reported in the registry record.
In general, an estimate from a time-to-event analysis would need to be interpreted in light of its uncertainty, follow-up, and event definition. A confidence interval describes the range of effect estimates compatible with the data and model at the stated confidence level; it does not guarantee that the true effect lies within a particular observed interval. None is available for this study. There is also no reported direction or magnitude of effect to assess for precision, clinical relevance, or consistency.
The planning assumptions mention a two-sided significance level of 0.05 and equal allocation between arms, and describe a normal approximation. Those assumptions do not constitute results. The planning description refers to fractions of an observed effect, but the record reports no observed trial effect. Thus no trial-specific interpretation can be drawn from the planning language. The evidence from this record is limited to the study's intended comparison and outcome, plus its termination and absence of collected or analyzed data.
9. Statistical Methods Explained
What was the planned time-to-event method?
The registered method for the primary outcome was a cause-specific hazard Cox model with treatment group as a covariate. In general, a hazard describes the instantaneous rate at which an event occurs among participants who have not yet experienced that event and remain under observation. A Cox model relates that rate to explanatory variables without requiring the baseline hazard to follow a particular parametric shape. The registry record does not report model estimates or a fitted model, because it states that no analysis was done.
In general, a cause-specific analysis distinguishes events according to their cause. That distinction matters when different causes of an event may have different interpretations. The record planned to document whether removal was due to decreased drainage, complications, or other reasons. It does not report how the planned analysis would handle competing causes in detail, how event times would be defined, or what assumptions would be checked.
What does censoring mean in general?
For time-to-event data, censoring occurs when the event time is not observed for a participant during the available follow-up. The information that the participant remained event-free up to the last observed time can still contribute to an analysis, but it does not reveal what happened later. Valid interpretation depends on how censoring arises and how it is handled. The registry record gives a 1 month timeframe but does not report follow-up records, censoring counts, or a censoring strategy. Since no data were collected, there is no basis for assessing censoring in this trial.
What would the treatment covariate represent?
In general, including treatment group as a covariate in a Cox model estimates the association between assigned group and the event rate, conditional on the model specification. A treatment contrast is not, by itself, proof of causation or clinical importance. Random allocation can support a fair comparison when it is implemented as planned and the analysis preserves that comparison, but details about allocation procedures are not reported in the registry record. No treatment coefficient, hazard estimate, confidence interval, or test result is reported for this study.
What do the planning assumptions mean?
The registry's planning description specifies a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect. For time-to-event planning illustrations, it describes the total number of events using the Schoenfeld approach; for other outcomes, it describes participants per arm. These are planning conventions, not observed trial outcomes. Because the record says no data were collected and no analysis was done, it reports no observed trial effect that can serve as a basis for a trial-specific effect estimate.
In general, power calculations estimate the amount of information a design may need to detect a specified effect under stated assumptions. They are not a measure of the probability that a completed study has found a real effect, and they cannot substitute for observed results. The record does not report the trial's own sample-size justification or protocol-based calculation. The planning description should therefore not be read as evidence that the trial was adequately sized or as an observed-power result.
Why can over-dispersion matter in general?
For count outcomes, over-dispersion means that variability exceeds what a simple model assumes. Ignoring it can make standard errors too small and uncertainty appear narrower than it is. This is a general statistical issue, not a reported feature of this trial: the primary endpoint was time to catheter removal, and the record reports no fitted model or outcome data. The record does not describe an over-dispersion assessment or a count-outcome model.
Overall, the listed methods are an intended analysis plan rather than a completed analysis. Specific model diagnostics, covariate adjustments beyond treatment group, handling of missing observations, and analysis-population definitions are not reported in the registry record. Without collected observations, no method can yield a trial-specific estimate or quantify its uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 2 outcome measures, but no analysis was conducted. The primary outcome is identified as time to catheter removal; the details of the other outcome measure are not described in the available record. It is not reported in the registry record whether the trial had a prespecified strategy to control multiplicity across outcomes, time points, or other analyses. Without completed tests or estimates, there is no multiplicity-adjusted or unadjusted result to interpret.
Missing-data methods are also not reported in the registry record. This is distinct from ordinary missingness within an analyzed dataset: the primary outcome statement says that no data were collected. As a result, there are no observed participant outcomes from which to characterize missingness, apply an imputation method, or compare complete-case and other analyses.
The record does not define an intention-to-treat, per-protocol, or other analysis population. It lists enrollment as 3, while also stating that no data were collected and no analysis was done. The record does not explain that combination, so it cannot establish which participants, if any, were included in an outcome analysis. There are no reported exclusions, withdrawals, or loss-to-follow-up details.
In general, multiplicity plans and analysis-population definitions help readers understand which comparisons were planned and who contributed to each result. Here, neither can be evaluated through reported estimates, because there are no analyses or results.
11. What the Result Does, and Does Not, Mean
This record establishes that investigators planned a randomized, double-blind comparison of IPC plus saline with IPC plus doxycycline, with time to catheter removal as the primary outcome. It also records that the study was terminated due to slow accrual and the design of the study. Most importantly for statistical interpretation, the primary outcome statement says that no data were collected and no analysis was done.
Accordingly, the record does not show that one treatment resulted in more or fewer catheter removals, or that removal occurred sooner or later in either group. It does not quantify uncertainty or support a conclusion about comparative effectiveness or safety. The zero values in the adverse-event fields do not change that interpretation, because the record says no data were collected.
In general, a randomized design describes how a comparison is intended to be made; it does not itself provide evidence about the result. A planned model describes how data could be analyzed; it does not produce an estimate in the absence of observations. Likewise, planning assumptions and sample-size illustrations cannot replace observed outcomes. No claim about treatment benefit, lack of benefit, or equivalence follows from the absence of results.
The appropriate reading is therefore limited: the trial's intended question and methods are documented, but the registry record contains no analyzable outcome evidence with which to answer that question. Any conclusion beyond that would require information not reported in the registry record.
12. Why This Trial Matters Statistically
This study illustrates the distinction between a trial design and a trial result. Randomization, masking, a defined comparator, and a time-to-event endpoint describe the planned framework for a comparison. They do not establish an observed treatment difference. Because the registry record says the study was terminated and no data were collected or analyzed, the statistical question remains unanswered in this record.
The endpoint also illustrates why event definitions matter. Catheter removal was to be classified by cause, with decreased drainage, complications, and other reasons listed. In general, combining or separating event causes affects the question an analysis answers. A cause-specific model is meaningful only when event causes and follow-up are recorded and the analysis rules are clear. No such outcome data are available.
The record's enrollment entry and its statement that no data were collected also demonstrate the value of reading registry fields in context. An enrollment count alone cannot establish that primary endpoint observations exist or that an analysis was possible. Similarly, zero-valued adverse-event fields should not be treated as evidence of zero events when the record explicitly reports no data collection.
Finally, planning assumptions should not be confused with evidence. The stated significance level and allocation assumptions describe planning, while the missing observations prevent assessment of effect size, precision, and model performance. This is a useful statistical distinction for interpreting terminated trials: a registry may document a carefully framed question without containing results that answer it.
13. 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 central limitation is that the registry record states that no data were collected and no analysis was done. There are therefore no outcome estimates, participant-level observations, confidence intervals, p-values, or event counts available to assess. The listed enrollment of 3 does not resolve this limitation; the record does not explain how that entry relates to the absence of collected data.
The termination is attributed to slow accrual and the design of the study, but further details are not reported in the registry record. The record does not describe recruitment progress, reasons for slow accrual, changes to the protocol, or whether any aspect of the design was modified. It also does not report detailed eligibility criteria or baseline characteristics.
Important analysis details are absent, including allocation procedures, the practical implementation of double masking, event-time definitions, handling of censoring or competing causes, missing-data methods, analysis populations, and model diagnostics. The registry identifies a planned cause-specific hazard Cox model but provides no fitted model or results. The brief arm descriptions are truncated, limiting what can be said about operational procedures.
The adverse-event fields show zeros, but the record's statement that no data were collected prevents interpreting these as a demonstrated absence of harms. The registry also lists 2 outcome measures without supplying analysis results or a multiplicity strategy. These gaps prevent assessment of both the planned comparison and its statistical execution.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Indwelling Pleural Catheter With Either Doxycycline or Saline at Day 7 for Pleurodesis — NCT02623959.
- Registry record last updated 2019-08-07; status last verified 2019-07.
- Results first posted 2019-07-26.
- 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.
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17. Record Summary
The registry record describes NCT02623959, a Phase 4 randomized, double-blind, parallel-group study sponsored by M.D. Anderson Cancer Center. It planned to compare indwelling pleural catheters used with saline or doxycycline for malignant pleural effusions. The listed primary outcome was time to catheter removal over 1 month, analyzed using a cause-specific hazard Cox model with treatment group as a covariate.
The record lists enrollment as 3 and gives a study start date of 2016-04-27 and primary completion date of 2017-05-23. Its status is terminated, with slow accrual and the design of the study cited as the reason. The primary outcome entry explicitly states that no data were collected and no analysis was done. No treatment effect, safety result, or inferential conclusion is reported.