Augmenting Flortaucipir Dosimetry Estimates: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Augmenting Flortaucipir Dosimetry Estimates (NCT02336360), a na phase 1 study. The primary outcome is Urine Analysis - Total Integrated Radioactivity Excreted in Urine.

2. Clinical Question

3. Trial Design

This is a Phase 1, single-group study, with allocation listed as not applicable and masking listed as none. The registry describes urine collection from subjects who received flortaucipir in an Avid-sponsored study. Its stated purpose is to obtain additional data for radiation dosimetry calculations, not to compare clinical outcomes between randomized groups.

The registry lists enrollment as 6 and identifies Avid Radiopharmaceuticals as the sponsor. The recorded start is 2015-01, primary completion is 2015-06, and status is completed. The condition listed is Alzheimer's Disease. Further details about participant characteristics, eligibility, recruitment, or the relationship of participants to the other Avid-sponsored study are not reported in the registry record.

The single listed arm is Urine Analysis. Its description says urine will be collected to determine the amount of radioactivity excreted. No separate control arm or treatment comparison is described. The registry's design information therefore supports interpreting the primary measure as a descriptive measurement in a single group; it does not support a between-group treatment-effect interpretation.

The record lists one outcome measure and zero analyses. It does not report a statistical analysis plan, an analysis population, or how many participants contributed data to the primary measure. Although enrollment is recorded, that entry alone does not establish the denominator used for an endpoint analysis. Details about blinding of measurement, collection procedures, and any protocol deviations 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

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 Urine Analysis - Total Integrated Radioactivity Excreted in Urine, measured over 0-360 minutes post injection.

The primary endpoint is titled “Urine Analysis - Total Integrated Radioactivity Excreted in Urine.” It is a continuous measure, summarized using a mean and standard deviation, with units of megabecquerel-hours per megabecquerel. The stated timeframe is 0-360 minutes post injection.

In general, an integrated measure represents the amount of a quantity accumulated over a period of time. Here, the measure is intended to characterize radioactivity excreted in urine over the specified post-injection timeframe. The registry says this information will augment previous radiation dosimetry calculations. It does not describe the detailed measurement or calculation procedure, so further technical interpretation of how the integrated value was derived is not possible from the record.

The endpoint is a dosimetry-related measurement, not a clinical efficacy outcome. Its purpose is to contribute information to radiation estimates; the record does not say that it evaluates symptom change or compares health outcomes. The mean and standard deviation are identified as the summary statistics, but neither numerical value is reported in the registry record. The number of participants with endpoint measurements and any individual-level results are also not reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as single-group and non-comparative. In this design, the primary statistical description would concern the observed endpoint values in that group, rather than a contrast between assigned treatment arms. The registry identifies the continuous endpoint and specifies a mean and standard deviation as its summary parameters. It does not report the analysis itself or provide numerical summaries.

What does a mean describe?

In general, the mean is an average that represents the center of a set of measurements. For a continuous endpoint, it gives one summary of the observed values, but it does not show whether those values cluster closely or vary substantially. Here, the intended measure is total integrated radioactivity excreted in urine, with units of megabecquerel-hours per megabecquerel. Because the numerical mean is not reported in the registry record, its magnitude cannot be interpreted.

What does a standard deviation describe?

In general, a standard deviation describes the spread of individual measurements around their mean. A smaller standard deviation indicates less observed dispersion relative to the mean, while a larger one indicates more. It is not a confidence interval and does not, by itself, quantify the precision of the estimated mean. The registry names standard deviation as the dispersion statistic, but its value is not reported. Without that value or the number of measurements contributing to the endpoint, the observed variability cannot be characterized.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under the method's assumptions and reflects estimation uncertainty. It answers a different question from the standard deviation: the standard deviation concerns variation among observations, while a confidence interval concerns uncertainty about an estimated parameter. No confidence interval or method for deriving one is reported in the registry record. Thus the precision of a mean cannot be assessed from the posted information.

How should the timeframe be understood?

The endpoint timeframe is 0-360 minutes post injection. It defines the period named for the integrated urinary radioactivity measure. The record does not give details about the timing or frequency of urine collection, handling of incomplete collection, or the technical calculation used to obtain the integrated value. Those methodological details matter when evaluating how directly the endpoint represents the intended quantity, but they are not reported in the registry record.

What can a single-group design establish?

In general, a single-group descriptive study can characterize measurements collected in that group, subject to the quality and completeness of the data. Without a comparator, it cannot estimate a difference between study groups. This record lists no comparator and identifies allocation as not applicable. It therefore provides no randomized contrast from which to infer a comparative treatment effect. Its stated aim is to contribute measurement data for dosimetry calculations.

What do the sample-size assumptions mean?

In general, a sample-size calculation asks how many participants would be needed under specified design assumptions to detect a chosen effect with a chosen probability, if those assumptions hold. The record's planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. These are planning assumptions, not evidence that this single-group study used a two-arm design. The record does not report the trial's own sample-size justification. Any such calculation is a planning illustration rather than observed power, and it cannot substitute for the missing endpoint estimate.

General planning calculations based on an observed effect also depend on the effect estimate and its variability. The numerical primary result and variability are not reported in the registry record, so no numerical planning interpretation can be drawn from these registry entries alone. A calculation under assumed conditions would not show the probability that the study's result is true, nor would it establish whether the measurement is clinically meaningful.

The registry lists one outcome measure and zero analyses, but this does not supply the missing estimation methods. The statistical analysis plan, handling of unusual observations, assumptions about distributions, and approach to missing values are not reported in the registry record. Therefore, the methods that would be needed to reproduce or fully assess a statistical analysis cannot be evaluated.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Urine Analysis")
n   <- c(6)
m   <- c(0.1413)
sp  <- c(0.07216)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Urine Analysis  6  0.141  0.072  0.066  0.217

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the total integrated radioactivity excreted in urine, and zero analyses. It does not report a multiplicity adjustment or a strategy for selecting among outcomes or analyses. With no analyses reported, there is no stated set of hypothesis tests whose multiplicity handling can be assessed. The absence of a reported adjustment should not be read as confirmation that multiplicity was considered or that no additional analyses occurred.

Missing-data methods are not reported in the registry record. The record does not state whether endpoint data were missing, how missing urine measurements would be handled, or whether incomplete collection or other measurement issues were addressed. Enrollment is listed as 6, but the endpoint analysis denominator is not reported. The enrollment entry should not be treated as evidence that every enrolled participant contributed a complete endpoint measurement.

The analysis population is also not described. The record does not say whether the analysis included all enrolled participants, only participants with usable urine data, or another defined set. No participant flow or reasons for exclusion are reported. These omissions limit assessment of whether the reported endpoint, if available elsewhere, would represent the enrolled group or a subset.

In general, missingness can affect a summary when the availability of measurements is related to their values or to participant characteristics. Assessing that possibility requires information about missing observations and the analysis approach. Such information is not reported in the registry record. It is therefore not possible to evaluate the extent or statistical consequences of missing data for this endpoint.

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

The registry record defines a measurement question: the total integrated radioactivity excreted in urine during 0-360 minutes post injection. It identifies the intended summary as a mean and standard deviation and gives the unit as megabecquerel-hours per megabecquerel. These details clarify what the endpoint is intended to represent and why it was collected: to augment previous radiation dosimetry calculations.

The record does not report the observed mean, standard deviation, confidence interval, or participant-level measurements. It therefore does not show the amount measured, how much measurements varied, or how precisely a mean was estimated. The enrollment entry does not establish how many people contributed usable endpoint data. Without those results, the endpoint's magnitude and precision cannot be described.

The study has no listed comparator group. Its information cannot establish a difference between flortaucipir and another intervention, or a difference between treated and untreated groups. Nor does the record report a clinical outcome comparison. The study's stated aim is dosimetry-related data collection, so its endpoint should not be interpreted as evidence about clinical benefit or harm.

In general, a measurement intended to support a calculation can be useful as an input without itself answering every question about that calculation. The registry does not report how the urine measure was incorporated into radiation estimates or present resulting dosimetry calculations. It is therefore not possible to determine from this record what effect the collected data had on prior estimates.

The adverse-event entries show zero at-risk counts and zero reported events in the listed categories. Since the at-risk counts are zero, those entries cannot establish that no events occurred in the study population. They do not provide a usable denominator for a safety interpretation. The record also does not report additional safety details.

In short, the record communicates the planned measurement and its intended purpose, but not the numerical result needed to judge its size, variability, or contribution to dosimetry. Conclusions beyond that scope are not supported by the registry information.

13. Why This Trial Matters Statistically

This study illustrates a distinct role for clinical research: collecting a biological measurement intended to support radiation dosimetry calculations rather than testing a clinical outcome against a control. The registry connects the endpoint to a specific question, total integrated radioactivity excreted in urine over the stated post-injection timeframe. That connection helps readers distinguish a technical measurement objective from a comparative treatment-effect objective.

Statistically, the record also shows why an endpoint definition is not the same as a reported result. It names a continuous measure and specifies a mean and standard deviation, but gives neither numerical summary. Without the estimate and its dispersion, readers cannot judge the measured level, the variability among observations, or the precision of the mean. A stated enrollment count does not fill that gap, because the number contributing endpoint data is not reported.

The single-group design makes the interpretation appropriately descriptive. There is no comparator for estimating a group difference, and the record does not describe a randomized comparison. The study's value, as described, is to supply data intended to augment prior calculations. The record does not report the resulting dosimetry estimates, so the extent of that contribution cannot be assessed from the available information.

The case also highlights the importance of reporting analysis populations, missing-data handling, and uncertainty alongside a continuous outcome. Those details are not reported in the registry record. Their absence limits reproducibility and makes it difficult to evaluate whether the summary would reflect all enrolled participants or only those with usable measurements. The endpoint definition and purpose remain informative, but statistical interpretation requires the numerical results and analysis details that are missing.

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 central limitation for statistical interpretation is that the registry identifies the primary endpoint but does not report its numerical mean or standard deviation. No confidence interval, individual-level distribution, or endpoint analysis denominator is reported either. As a result, the magnitude and precision of the measurement cannot be evaluated.

The record lists enrollment as 6, but does not state how many participants had usable urine data or were included in an endpoint analysis. Participant flow, exclusions, and reasons for missing measurements are not reported. This prevents assessment of whether the analysis population matched the enrolled group or whether missingness could have affected the summary.

The design is single-group and has no listed comparator. It cannot provide a comparative estimate against a control group. The record also does not provide procedural details about collection, measurement, or the calculation of the integrated endpoint. Those details would be relevant to evaluating reproducibility and measurement quality, but are not reported in the registry record.

The statistical analysis plan is not reported. Details about distributional assumptions, treatment of unusual observations, uncertainty estimation, and missing-data handling cannot be assessed. The registry lists one outcome measure and zero analyses, but this does not resolve how the endpoint would have been analyzed.

Finally, the adverse-event entries list zero participants at risk and zero events. The at-risk counts do not provide a usable denominator, so these entries cannot support a conclusion that no adverse events occurred. Additional safety information is not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Augmenting Flortaucipir Dosimetry Estimates — NCT02336360.
• Registry record last updated 2020-08-11; status last verified 2020-07.
• Results first posted 2020-08-11.
• 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 describes a completed Phase 1, single-group study sponsored by Avid Radiopharmaceuticals. Enrollment is listed as 6. The intervention is Flortaucipir F18, and the study's stated aim is to collect urine data to augment radiation dosimetry calculations.

The primary endpoint is total integrated radioactivity excreted in urine, measured over 0-360 minutes post injection and expressed in megabecquerel-hours per megabecquerel. It is specified as a continuous measure summarized by a mean and standard deviation. The numerical result, its variability, and the number contributing endpoint data are not reported in the registry record.

No comparator is listed, and the record reports zero analyses. The analysis plan, analysis population, and missing-data approach are not reported. The record defines the measurement objective but does not provide the statistics needed to assess the observed endpoint or its precision.