Intra-Arterial Chemotherapy for Newly Diagnosed, Residual, or Recurrent Atypical Choroid Plexus Papilloma and Choroid Plexus Carcinoma Prior to Second-Look Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Intra-Arterial Chemotherapy for Newly Diagnosed, Residual, or Recurrent Atypical Choroid Plexus Papilloma and Choroid Plexus Carcinoma Prior to Second-Look Surgery (NCT04994977), a na phase 1 study. The primary outcome is Safety of Intra-arterial Chemotherapy in Subjects With ACPP and CPC, Measured by the Number of Serious Adverse Events That Are Reported as at Least Possible Related to the Intervention That Occur in Subjects on the Trial.

2. Clinical Question

Statistically, this is a descriptive safety question in a single-group Phase 1 study, not an estimate of a treatment effect against a control. The registry lists an enrollment of 1, and its posted serious adverse event summary reports no affected participants. With so little information about experience in the intended population, the safety count is best read as a record of what was reported for this study, not as a precise estimate of the frequency of adverse events in a broader population. The termination status and the absence of reported outcome analyses also limit what can be concluded about tumor response or surgical outcomes.

3. Trial Design

NCT04994977 is registered as a Phase 1, single-group study with no masking. Allocation is recorded as not applicable, consistent with the absence of a listed randomized comparison. The registry names an intra-arterial chemotherapy group and describes administration of melphalan, carboplatin, and topotecan after heparin pretreatment. The drugs were to be given consecutively by intra-arterial infusion; multiple arteries could be used without changing the total dose of the drugs.

The intended setting was treatment before second-look surgery for newly diagnosed, residual, or recurrent ACPP or CPC. The primary outcome focuses on serious adverse events considered at least possibly related to the intervention, with a timeframe of about 6 months since the start of therapy. Listed secondary outcomes cover successful angiography and catheter placement, tumor volume and vascularity responses assessed by MRI, and features of second-look surgery, including extent of resection and blood loss.

The registry record lists an enrollment of 1. The recorded start date is 2023-05-04, the primary completion date is 2024-07-23, and the status is terminated. The reason for termination is not reported in the registry record. Although the record lists 10 outcome measures, it reports 0 analyses. The statistical analysis plan, including any prespecified method for summarizing the primary endpoint, is not reported in the registry record.

These design details matter when interpreting the posted numbers. A single-group study can describe events reported among treated participants, but without a comparator it cannot separate outcomes associated with treatment from outcomes that might have occurred for other reasons. The enrollment also makes the record a very limited source of information about variability across participants. The listed time window describes the intended endpoint timeframe; the registry record does not establish how completely follow-up was achieved.

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 Safety of Intra-arterial Chemotherapy in Subjects With ACPP and CPC, Measured by the Number of Serious Adverse Events That Are Reported as at Least Possible Related to the Intervention That Occur in Subjects on the Trial, measured over about 6 months since the start of therapy.

The primary endpoint is a count of serious adverse events reported as at least possibly related to the intervention. Its timeframe is about 6 months since the start of therapy. A serious adverse event is an event classified as serious in the study’s safety reporting; the endpoint further restricts the count to events with at least possible attribution to the intervention. This makes it a safety-focused measure rather than a measure of tumor response or surgical success.

General statistical context: counts are useful when the question is how many events were observed, but a count alone does not convey the amount of time each participant was observed, the clinical details of events, or the uncertainty around the underlying event frequency. For a count to support comparisons or estimates, the analysis must specify how events and exposure are handled. Such a method is not reported in the registry record.

The endpoint is relevant to a Phase 1 investigation because it directly captures reported serious harms considered potentially related to the intervention. However, the posted count should not be read as a complete measure of tolerability or as proof that serious harm cannot occur. The record reports an enrollment of 1 and no primary-outcome analysis results. The safety summary reports 0 serious adverse events affecting the participant at risk, but does not provide a confidence interval or an inferential estimate. The record also does not report event-level descriptions or a separate account of follow-up completeness.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of endpoint is being counted?

The primary outcome is a count: serious adverse events reported as at least possibly related to intra-arterial chemotherapy. Unlike an average measurement, a count records how many qualifying events were observed. The registry identifies the unit as a count of serious adverse events and gives the timeframe as about 6 months since the start of therapy. It does not state whether multiple events in one participant would be counted separately, how repeated events would be handled, or what method would be used to summarize the count. Those details are not reported in the registry record.

General statistical context: count data are nonnegative and can be highly uneven. Some studies observe no events, while a small number of participants may contribute multiple events. The appropriate method depends on whether the target is the number of participants with any event, the total event count, or an event rate accounting for time at risk. Those are different quantities. A count of affected participants is not interchangeable with a count of all events, and neither is automatically an event rate.

Why can over-dispersion matter?

General statistical context: a simple count model may assume that variability follows a particular relationship to the average count. Over-dispersion means the observed variability is greater than that assumption allows. If over-dispersion is ignored, standard errors and confidence intervals can be too small, making uncertainty appear less than it is. Alternative models or robust methods can sometimes address this, but choosing among them requires data and a prespecified analysis strategy. The registry record does not report a count model, a dispersion assumption, or an analysis strategy. With an enrollment of 1 and no posted analysis, there is no basis in the record to assess model fit or dispersion.

What would a confidence interval contribute?

General statistical context: a confidence interval communicates uncertainty around an estimated quantity. For an event count or event frequency, the interval depends on the estimand, the observation time, the statistical model, and assumptions about how events arise. A confidence interval is not a substitute for describing the data or the method, and it cannot remove limitations caused by very sparse information. No confidence interval is reported for the primary outcome. The posted safety counts should therefore be read directly, without implying precision that the record does not establish.

How should the planning illustration be understood?

The registry’s planning assumptions describe an 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 illustration describes the effect to detect as a stated fraction of the observed effect. For time-to-event calculations, the assumptions refer to total events; for other calculations, they refer to participants per arm for 80% power or the other stated power level. These are planning assumptions, not a report of the trial’s design or an observed power calculation.

That distinction is especially important for this record. The registered study is single-group, not a two-arm randomized comparison, and the registry does not report an outcome analysis from which an observed effect for such planning can be interpreted. The planning illustration should not be taken as evidence that the study was designed with equal allocation, that it enrolled two arms, or that it had a particular probability of detecting an effect. Sample-size calculations are planning illustrations, not observed power.

What analyses are actually reported?

The registry lists 10 outcome measures and 0 analyses. It does not report a statistical test, estimation procedure, model, adjustment strategy, or confidence interval for the primary outcome. The listed secondary outcomes identify what the study intended to assess, but their methods and results are not reported in the registry record. Without analysis details, readers cannot determine how missing observations, repeated measurements, multiple events, or outcomes measured on different scales would have been handled.

General statistical context: a prespecified analysis can clarify which outcome is primary, how it is defined, what population is included, and how uncertainty is quantified. In its absence, readers should distinguish outcomes named in the registry from analyses actually reported. For this study, the posted serious adverse event counts are descriptive. The record does not support a recalculated effect estimate or a comparison with another group. No sponsor analysis is reported to take precedence over a recalculation; rather, the registry reports no analyses.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures, including the primary safety count and secondary measures of angiography, MRI-assessed tumor response, and second-look surgery. It reports 0 analyses. A statistical plan for handling multiple outcomes, including whether any secondary outcomes were exploratory or how comparisons would be controlled, is not reported in the registry record. Without those details, the list of outcomes should not be mistaken for a set of confirmed findings or for evidence that each outcome was tested.

General statistical context: when many outcomes are examined, the chance of seeing an apparently notable result by chance can increase if each is tested separately. Multiplicity procedures can address this issue, but the appropriate approach depends on the study question and analysis plan. No such procedure is reported, and no outcome analysis is posted from which to assess it.

The registry record does not report a missing-data method, a description of missing observations for the listed outcomes, or rules for including participants in each analysis. It does not define analysis populations such as an intention-to-treat or per-protocol population. Since the enrollment is 1 and the record reports 0 analyses, the extent and consequences of any missing outcome data cannot be assessed from the registry record. The listed timeframe for the primary endpoint does not by itself confirm that follow-up was complete. These gaps limit interpretation of both the safety summary and the unreported response and surgery outcomes.

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 0% reporting threshold.

The posted safety summary lists the intra-arterial chemotherapy group with 1 participant at risk for serious adverse events and 0 affected. For other adverse events, it lists 1 at risk and 0 affected. The number of deaths is 0. These figures are counts in the registry record; they are not comparative rates or estimates of risk for a wider population.

The primary endpoint is narrower than a count of all health events: it includes serious adverse events reported as at least possibly related to the intervention, within about 6 months since the start of therapy. The summary does not include event descriptions or an uncertainty interval. A count of 0 in a study with an enrollment of 1 is therefore a limited observation, not evidence that the intervention has no potential for serious adverse events. It also does not establish that every possible adverse event was captured or that follow-up was complete; those details are not reported in the registry record.

General statistical context: rare outcomes are difficult to characterize when observations are sparse. A zero count can occur even when an underlying risk is greater than zero, and an interval estimate would communicate uncertainty only under explicit assumptions. No such estimate is reported. The safety figures should be read as the posted counts for this study and not as proof of safety, absence of risk, or a comparison against another treatment.

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

The record documents a Phase 1 investigation of intra-arterial chemotherapy before second-look surgery in people with ACPP or CPC. It describes a single-group intervention involving melphalan, carboplatin, and topotecan and sets a primary safety question around serious adverse events considered at least possibly related to the intervention. The posted safety summary records 0 serious adverse events affecting the participant at risk, 0 other adverse events affecting the participant at risk, and 0 deaths.

Those numbers describe the safety summary for this study. They do not demonstrate that the intervention is free of serious risks, because the record lists an enrollment of 1 and provides no uncertainty estimate. The data also do not show whether tumor volume or vascularity changed, whether angiography was successful, or whether second-look surgery achieved a particular result. Although those outcomes are listed, analyses are not reported in the registry record.

The single-group design does not provide a concurrent comparator for estimating how outcomes might differ without the intervention or under another treatment. Consequently, the record cannot establish a comparative treatment effect. The stated intention to assess safety, feasibility, tumor response, and surgical outcomes describes the study’s aims; it does not establish that those aims were met.

The terminated status is also not an explanation of what happened. The reason for termination is not reported in the registry record, so it cannot be attributed to safety, efficacy, recruitment, or any other cause. Overall, the posted information is a sparse, descriptive account of a small Phase 1 study. It is useful for identifying the intervention, intended outcomes, and reported safety counts, but it does not support broad conclusions about safety or efficacy.

13. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the gap between a clearly stated clinical question and the evidence needed to estimate an effect. The registry identifies a safety endpoint, a defined timeframe, and additional outcomes related to imaging and surgery. Those details establish what investigators intended to observe. The record also shows why an endpoint list alone is not enough: it reports 10 outcome measures but 0 analyses.

For a single-group Phase 1 study, descriptive safety counts can document what was recorded during the study. They cannot, by themselves, distinguish outcomes associated with the intervention from events that might occur for other reasons. An enrollment of 1 also leaves little information about how outcomes vary across the intended population. A zero in the posted safety summary is a real feature of the record, but its scope is limited to that recorded experience.

The study also highlights the importance of matching statistical planning assumptions to the registered design. The planning illustration describes equal allocation between two arms, while the trial is registered as single-group. That illustration should therefore be interpreted as a planning scenario rather than the trial’s own design or an observed assessment of power. Stating this distinction helps prevent a hypothetical calculation from being mistaken for evidence generated by the study.

Finally, the absence of reported analyses and the unspecified reason for termination leave important questions unresolved. Readers cannot evaluate the tumor-response or surgical outcomes, assess the handling of missing data, or understand why the study ended. These limits do not erase the descriptive safety information, but they define what statistical conclusions the record can support.

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 principal limitation is the very limited enrollment: the registry lists 1 participant. This restricts the amount of information available about variability in safety outcomes and makes the posted counts unsuitable as precise estimates for a wider population. The safety summary does not include confidence intervals or other measures of uncertainty.

The study is registered as single-group, with allocation recorded as not applicable and no masking. The registry does not specify a comparator arm. As a result, the record does not support a randomized or concurrent between-group comparison. The study’s stated interest in tumor reduction and surgical outcomes cannot be interpreted as evidence of a treatment effect without reported outcome results and an appropriate comparison.

Although 10 outcome measures are listed, the registry reports 0 analyses. Results for angiography, MRI-assessed tumor volume and vascularity, and the listed measures of second-look surgery are not reported in the registry record. The statistical analysis plan, handling of missing data, definition of analysis populations, and methods for addressing multiple outcomes are also not reported.

The record marks the study as terminated but does not report the reason. It does not establish whether the intended timeframe of about 6 months was completed for the participant, or describe the completeness of outcome ascertainment. These study-specific omissions limit interpretation beyond the posted safety counts. No cause for termination or unreported outcome should be inferred from the available registry information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Intra-Arterial Chemotherapy for Newly Diagnosed, Residual, or Recurrent Atypical Choroid Plexus Papilloma and Choroid Plexus Carcinoma Prior to Second-Look Surgery — NCT04994977.
• Registry record last updated 2026-06-08; status last verified 2026-05.
• Results first posted 2026-06-08.
• 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

NCT04994977 is a Phase 1, single-group study of intra-arterial chemotherapy before second-look surgery for newly diagnosed, residual, or recurrent ACPP and CPC. The intervention description specifies heparin pretreatment followed by consecutive intra-arterial doses of melphalan, carboplatin, and topotecan. The primary endpoint is the count of serious adverse events reported as at least possibly related to the intervention during about 6 months since the start of therapy.

The registry lists an enrollment of 1, a start date of 2023-05-04, a primary completion date of 2024-07-23, and a terminated status. The posted safety summary reports 0 serious adverse events affecting the participant at risk, 0 other adverse events affecting the participant at risk, and 0 deaths. The registry lists 10 outcome measures and reports 0 analyses. Results for the listed tumor-response and surgical outcomes, the reason for termination, and the statistical analysis plan are not reported in the registry record.