A Study of TAK-660 in Surgical Procedures for People With Hemophilia A.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of TAK-660 in Surgical Procedures for People With Hemophilia A. (NCT04941898), a registered phase not stated study. The primary outcome is Number of Participants With Adverse Events.

2. Clinical Question

3. Trial Design

NCT04941898 is listed as a completed special drug use result survey of perioperative TAK-660, also called Adynovate. The registry describes use during surgery and other invasive procedures, including tooth extractions, among people with hemophilia A. The listed intervention is PEGylated recombinant factor VIII. Enrollment was 16, and the study’s recorded dates are 2021-06-30 for start and 2024-03-15 for primary completion.

The treatment approach was based on routine clinical practice rather than a treatment protocol imposed by the sponsor. Participants received infusions during their hospital stay, and clinic staff recorded what happened. The description says the sponsor would provide instructions for recording study information but would not be involved in how participants were treated. The listed dose was 15-50 international units per kilogram by slow intravenous injection every 8- 24 hours until bleeding was resolved or wound healing.

The registry does not describe a randomized allocation or a control arm; allocation is not stated. Consequently, the findings are descriptive results from the treatment group, not an estimate of a between-group treatment effect. The safety analysis set was defined as all participants who completed the survey. The reason that the safety results list 15 participants at risk while enrollment was 16 is not reported in the registry record.

The primary outcome was the number of participants with adverse events up to 30 days. Secondary outcomes address intraoperative hemostatic efficacy, hemostatic efficacy one day after surgery, and hemostatic efficacy at completion of perioperative management. The registry lists 8 outcome measures, but a detailed statistical analysis plan, including how each outcome was analyzed, is 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.

Before assignment: Participants with coagulation factor VIII (FVIII) deficiency who received Recombinant FVIII PEGylated (ADYNOVATE) for surgery/procedure were enrolled. Participants received ADYNOVATE Intravenous Infusion as part of a routine medical care.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety Analysis Set, The safety analysis set was defined as all participants who completed the survey.

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, The safety analysis set was defined as all participants who completed the survey.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Adverse Events, measured over Up to 30 Days.

The primary endpoint counts participants with adverse events up to 30 days. An adverse event is defined broadly as an unfavorable or unintended sign, symptom, disease, or abnormal laboratory finding occurring in time with use of a medicinal product. The definition does not require that the event be caused by the medicine. This distinction matters: an event recorded after treatment is not, by timing alone, evidence that treatment caused it.

A participant count is a binary outcome at the participant level: a person is classified according to whether an adverse event was recorded during the specified timeframe. This outcome is used to describe the observed safety experience in the survey population. It does not, by itself, measure event severity, duration, recurrence, or causal attribution. Those details are not reported for the primary endpoint in the registry record.

The safety results list 1 participant with serious adverse events and 1 with other adverse events, each among 15 participants at risk. These are reported categories; the record does not establish whether the same participant contributed to both. The endpoint is therefore best read as a descriptive count in the survey’s safety population, not as a controlled estimate of the risk attributable to TAK-660.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

For an outcome defined as the number of participants with an event, each person is classified according to whether the event was recorded within the stated timeframe. This differs from counting every occurrence: a person with repeated events may still contribute as a participant with an event rather than as multiple affected participants. The registry’s primary outcome is explicitly a participant count, while additional details about event recurrence are not reported in the registry record.

Counts are easiest to interpret alongside the population at risk. In this record, the adverse-event results list 15 participants at risk. The safety analysis set is defined as participants who completed the survey, while enrollment is 16. The reason for the difference is not reported in the registry record. A reader should therefore keep the enrollment figure distinct from the denominator used in the safety results.

What does a confidence interval add?

General statistical explanation: a confidence interval expresses the uncertainty around an estimated quantity under the method used to calculate it. A narrow interval indicates greater precision under that method; a wide interval indicates less precision. Counts from a small survey population can be imprecise even when the observed count is clear. The registry record does not report a confidence interval for the adverse-event results, so their precision cannot be quantified from the posted information.

General statistical explanation: a p-value assesses how compatible observed data are with a specified statistical model and null hypothesis. It does not show the probability that a treatment caused an event, nor does it measure clinical importance. No p-value or hypothesis test for the adverse-event findings is reported in the registry record.

Why does the comparison structure matter?

A randomized comparison can support estimation of a treatment contrast when the trial design and analysis are appropriate. This registry record does not describe randomization or a control group, and allocation is not stated. The reported counts therefore describe the treated survey group; they do not estimate a difference between treatments. Differences in participants, procedures, clinical decisions, or recording practices cannot be separated from treatment effects using these results alone.

The survey description says that infusions followed clinic standard practice and that the sponsor would not be involved in treatment decisions. This supports interpreting the results as routine-use observations, but the record does not provide detailed information about procedure mix, dose selection, or clinic-level practices. Those factors may affect how comparable the recorded experiences are across settings; their role cannot be assessed from the reported information.

What is the role of the sample-size assumptions?

General statistical explanation: a planning illustration asks how much information a future study might need under specified assumptions. It is not a result observed in the participants and does not indicate the probability that the completed study detected an effect. The registry record includes assumptions for a planning illustration, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions do not describe the survey’s treatment allocation, which is not stated, and do not turn the survey into a controlled comparison. The planning estimates themselves are not reported in the registry record.

Observed power is not a substitute for reporting uncertainty around the observed estimate. In this survey, no comparative effect estimate or confidence interval for the primary safety outcome is reported. The small set of recorded counts should therefore be read descriptively, without treating a planning calculation as evidence about the precision of the completed survey.

What is not specified?

The registry lists 8 outcome measures and no analyses. A detailed statistical analysis plan is not reported in the registry record. The record does not describe a model for the primary outcome, adjustment variables, a method for handling repeated events, or a procedure for estimating uncertainty. It also does not report whether any planned analyses were changed. Without these details, interpretation should stay close to the outcome definitions and counts that are actually listed.

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("Recombinant FVIII PEGylated Intravenous Infusion")
n      <- c(15)
events <- c(2)
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  Recombinant FVIII PEGylated Intravenous Infusion  15  2  13.3  1.7  40.5  3.7  37.9  4.0  38.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, including the primary adverse-event count and secondary hemostatic efficacy outcomes for the intraoperative period, one day after surgery, and completion of perioperative management. It lists no analyses. A method for controlling multiplicity, such as adjusting for examining several outcomes, is not reported in the registry record. No multiplicity adjustment or family of confirmatory tests should therefore be presumed.

The safety analysis set is defined as all participants who completed the survey. The adverse-event results list 15 participants at risk, whereas enrollment was 16. The reason for the difference, the completion status of the remaining enrolled participant, and any characteristics of participants without safety results are not reported in the registry record. Missing-data methods, imputation, and sensitivity analyses are also not reported.

These omissions limit assessment of how complete the recorded information was and whether missing observations could affect the descriptive results. The record does not state whether outcome assessments were available for every participant at each perioperative timepoint. It also does not explain how incomplete follow-up, if any, was handled. The safety counts should thus be understood as reported for the stated at-risk population, not as proof that outcome data were complete for all enrolled participants.

Because allocation was not stated and no control group is described, multiplicity considerations do not create a basis for a comparative efficacy conclusion. The registry does not provide inferential analyses for the listed outcomes.

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: melaena (6.7%).

The safety results list 1 participant with serious adverse events and 1 participant with other adverse events; the at-risk count is 15 for each category. These are participant counts, not necessarily counts of individual event episodes. The registry does not state whether the participant in the serious category is also included in the other category, so the categories should not be combined into a total.

Deaths are listed as 0. Melaena is the listed serious adverse-event term at 6.7%. That percentage is reported as a registry result; no additional event-level details or causal assessment are reported in the registry record. The record’s adverse-event definition includes events occurring in time with use of a medicinal product whether or not they are related to it. The presence of a reported event therefore does not establish that TAK-660 caused it.

These figures describe the safety results in the survey population. They do not provide a comparison with an untreated group or another treatment, and the registry does not report confidence intervals for the counts. Their interpretation should remain descriptive.

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

The result provides a record of adverse events observed during routine perioperative use of TAK-660 in the survey population. The listed safety results include 1 participant with serious adverse events and 1 with other adverse events, with 15 participants at risk in each category, and deaths listed as 0. The registry also identifies Melaena at 6.7% among the serious adverse-event terms. These observations can describe what was recorded in this survey, but they are not a controlled estimate of treatment-associated risk.

The broad adverse-event definition is important. It includes a medical occurrence associated in time with use of a medicinal product even when a causal relationship is not established. The counts therefore should not be read as proof that TAK-660 caused the recorded events. Likewise, the absence of reported deaths in this survey does not establish that a risk is absent in other populations or settings.

The record’s stated interest in bleeding control is reflected in secondary hemostatic efficacy outcomes, but those outcome results are not reported in the registry record. This means the posted safety figures alone do not answer how effective bleeding control was judged or what the assessments found.

The survey has no stated allocation and no control group described. It cannot show whether outcomes differ from those under another treatment or from outcomes without TAK-660. The findings also do not establish how well the observed experience applies to other procedures, clinics, or people with hemophilia A. They are best understood as descriptive registry results from the reported survey population, with substantial limits on causal and comparative interpretation.

14. Why This Trial Matters Statistically

Perioperative treatment raises questions that are not captured by a single measure. This survey records adverse events and identifies hemostatic efficacy outcomes during and after procedures. For statisticians, the distinction between those outcomes matters: the primary safety endpoint counts participants with adverse events, while the secondary outcomes concern assessments of bleeding control at specified perioperative stages. The registry does not report the secondary results, but their presence makes clear that safety and hemostatic efficacy are separate questions.

The routine-use setting is also statistically relevant. Treatment followed clinic standard practice, and the sponsor was not involved in treatment decisions. Such a design can describe experience in actual clinical practice, but the absence of a stated allocation and control group limits causal interpretation. The counts document what was recorded; they do not isolate a treatment effect from differences in participants, procedures, or clinical management.

Finally, clear population definitions are essential when reading a small descriptive result. Enrollment was 16, while the safety results list 15 at risk and define the safety analysis set by survey completion. The reason for the difference is not reported in the registry record. Making that distinction visible helps readers avoid treating enrollment and the safety denominator as interchangeable, and underscores why transparent reporting of analysis populations and missing data is important.

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 main limitation is the lack of a control group and the absence of a stated allocation. The adverse-event counts cannot be used to estimate a comparative effect or establish causation. The registry describes treatment according to clinic standard practice, but does not report details that would allow assessment of differences in procedures, dosing decisions, or participant characteristics across clinical settings.

The safety analysis set includes participants who completed the survey, and the safety results list 15 at risk compared with enrollment of 16. The reason for this difference and the handling of missing information are not reported in the registry record. The record also does not provide confidence intervals or other uncertainty estimates for the adverse-event results.

Details on the serious-event classification, event timing, individual event course, and causal assessment are not reported in the registry record. Although Melaena is listed at 6.7%, additional context for that term is not available in the stated results. The registry’s broad adverse-event definition includes events whether or not they are related to treatment.

Finally, although secondary outcomes address hemostatic efficacy during and after surgery, their results are not reported in the registry record. The statistical analysis plan, approach to multiplicity, and methods for handling repeated or incomplete outcome assessments are also not reported. These limitations restrict both the precision and scope of conclusions that can be drawn from the posted information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of TAK-660 in Surgical Procedures for People With Hemophilia A. — NCT04941898.
• Registry record last updated 2024-11-15; status last verified 2024-09.
• Results first posted 2024-11-15.
• 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

NCT04941898 is a completed special drug use result survey of TAK-660, also called Adynovate, for perioperative use in people with hemophilia A. The registry lists enrollment of 16 and describes administration according to clinic standard practice. The primary outcome was the number of participants with adverse events up to 30 days; the safety analysis set was defined as participants who completed the survey.

The safety results list 1 participant with serious adverse events and 1 with other adverse events, each among 15 participants at risk, with deaths listed as 0. Melaena is listed as a serious adverse-event term at 6.7%. The record does not describe a control group or randomized allocation, and does not report the secondary hemostatic efficacy results or detailed statistical analyses. The findings are descriptive and do not establish causation or comparative treatment effects.