Eltrombopag Olamine in Improving Platelet Recovery in Older Patients With Acute Myeloid Leukemia Undergoing Chemotherapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Eltrombopag Olamine in Improving Platelet Recovery in Older Patients With Acute Myeloid Leukemia Undergoing Chemotherapy (NCT02071901), a na phase 2 study. The primary outcome is Number of Participants With a Median Platelet Count >= 50,000/uL.

2. Clinical Question

Statistically, this is a descriptive question about threshold attainment in the treated study population. It can describe how often the endpoint occurred among the population used for analysis, but a single-group result alone cannot estimate a treatment-versus-control difference. Without a concurrent control group, the observed outcome cannot separate the effect of eltrombopag from the course of chemotherapy, supportive care, patient characteristics, or other influences. The registry also names secondary outcomes involving platelet-transfusion days, bleeding events, neutrophil recovery, hemoglobin change, and response to treatment. Their results are not reported in the registry record.

3. Trial Design

The registry describes a phase II, single-group study sponsored by Case Comprehensive Cancer Center. Enrollment is listed as 31. The allocation field is recorded as not applicable, and masking is listed as none. These features identify a nonrandomized, unmasked design without a concurrent control group. The registry status is completed.

Participants received eltrombopag olamine by mouth daily. The registered treatment rule specified continuing until platelet counts reached >= 50,000/uL or for 8 weeks, whichever came earlier. Treatment was to continue only in the absence of unacceptable toxicity. The primary endpoint is assessed on Day 24 of treatment, and its population is described as participants who completed the study. The number who completed the study is not reported in the registry record.

The study is framed around platelet recovery in older patients with AML receiving induction chemotherapy. The registry lists numerous AML conditions, but the eligibility criteria and how those listed conditions were applied are not reported in the registry record. The chemotherapy regimen, detailed supportive-care procedures, and participant-level baseline characteristics are also not reported in the registry record.

A single-group phase II design can describe outcomes observed during treatment and provide information about the feasibility of measuring those outcomes in the enrolled population. It does not, by itself, establish what would have happened to comparable participants without eltrombopag. Because allocation is not applicable and masking is absent, the record does not support a randomized treatment-effect estimate. The registry does not report a protocol-level statistical plan, so the intended approach to estimation, hypothesis testing, or adjustment cannot be established from the 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

Analysis population for the primary outcome, as defined in the registry: Participants who completed 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.

Population: Participants who went on study

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With a Median Platelet Count >= 50,000/uL, measured over Day 24 of Treatment.

The primary endpoint is the number of participants with a median platelet count >= 50,000/uL on Day 24 of treatment. It is a count of participants meeting a threshold, rather than a continuous summary of platelet counts for the whole study population. The registry identifies participants who completed the study as the population for this outcome.

A threshold endpoint can make a clinically defined recovery target straightforward to interpret: it distinguishes participants who meet the stated criterion at the stated assessment from those who do not. As a general statistical matter, converting a continuous measurement into a threshold can also discard information. Participants just below and well below the threshold are grouped together, as are participants just above and well above it. The endpoint therefore does not describe the full distribution of platelet counts or the amount of change from baseline.

The registry record does not report the number meeting the threshold, the number included in the primary analysis, or an uncertainty interval for the result. The result itself therefore cannot be interpreted from the registry record. The named endpoint also does not, on its own, quantify how much eltrombopag contributed to platelet recovery: that causal comparison would require a suitable counterfactual, which a single-group design does not supply.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary endpoint count?

The registered outcome is a count of participants meeting a platelet-count threshold on Day 24 of treatment. It is not a mean platelet count, a change from baseline, or a time-to-event estimate. The threshold is stated as >= 50,000/uL, and the outcome description refers to a median platelet count. The population is described as participants who completed the study. The record does not state the number of completers or the number meeting the criterion, so neither an observed frequency nor its precision can be read from the registry record.

In general, a binary endpoint sorts observations into categories, such as meeting or not meeting a defined criterion. This can make a result easier to communicate, but it removes detail about how close measurements were to the threshold and how far measurements were from it. Interpretation depends on a clear endpoint definition, a clear analysis population, and a reported numerator and denominator. Those numerical result details are not reported in the registry record.

What can a single-group design estimate?

A single-group study can describe what was observed among participants receiving the study intervention. It cannot directly compare those observations with outcomes under a concurrent alternative. In general, random allocation helps balance measured and unmeasured participant characteristics across groups, while a concurrent control group provides a reference for outcomes over the same study period. Neither feature is present in this registry's design description: allocation is not applicable, and the model is single group.

This distinction concerns the estimand, or the quantity the analysis is intended to estimate. A descriptive endpoint asks how many participants in the observed study population met the criterion. A comparative treatment effect asks how outcomes differ under alternative treatment strategies. The registered primary endpoint is descriptive, and the record does not identify a comparative estimand. No causal effect should be inferred from a single-arm result alone.

How should uncertainty be understood?

In general, an estimate based on a finite study population is subject to sampling uncertainty. A confidence interval conveys the range of values compatible with the data and model, and its width reflects precision. A narrower interval generally indicates greater precision than a wider interval, although precision is not the same as freedom from bias. An interval cannot address confounding or the absence of a control group.

The registry record does not report a confidence interval, a standard error, or an inferential analysis for the primary endpoint. It also lists 0 analyses. That field does not establish that no analyses were performed outside the registry; it means that analyses are not recorded in the registry material. The sponsor's analysis, if present elsewhere, is not reported in the registry record and cannot be reconstructed from the endpoint description alone.

What do the planning conventions mean?

The sample-size assumptions describe planning illustrations based on an observed effect, rather than the trial's own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as the stated fraction of the observed effect. For time-to-event outcomes, the illustration is based on a total event count using the Schoenfeld approach; for other outcomes, it is expressed as participants per arm.

As general concepts, a significance level defines a decision threshold for a test under a specified null model, while power is the probability of detecting an effect of a specified size under the assumptions of a design and analysis. A planning calculation is conditional on its assumptions; it does not describe the actual probability that a completed study detected an effect. It is not observed power. The assumptions involving two arms do not change the registered study into a two-arm trial: this study is recorded as single group with allocation not applicable. No numeric illustration results are stated in the registry record, and the primary observed effect is not reported there.

Why can over-dispersion matter?

In general, count outcomes may vary more than a simple statistical model expects. This is called over-dispersion. If a model assumes less variability than the data contain, standard errors may be too small and confidence intervals too narrow, leading to overly confident inferences. Methods that allow for extra variability can improve uncertainty estimates when their assumptions fit the data. The registry record does not identify a count model, an over-dispersion assessment, or a method for handling it. This is a general consideration, not a claim about an analysis used in this trial.

What can be concluded from the registry entries?

The record supports a description of the design, intervention rule, endpoint definition, and selected safety entries. It does not report the primary endpoint's observed count, an uncertainty estimate, or results for the listed secondary outcomes. Statistical interpretation must therefore distinguish the endpoint that was registered from a result that is not reported. The absence of a reported numerical outcome is not evidence that the outcome occurred or did not occur.

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("Supportive Care (Eltrombopag Olamine)")
n      <- c(31)
events <- c(30)
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  Supportive Care (Eltrombopag Olamine)  31  30  96.8  83.3  99.9  83.8  99.4  83.8  99.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 14 outcome measures and 0 analyses. It names a primary endpoint and several secondary outcomes, including platelet recovery, transfusion days, bleeding, neutrophil recovery, hemoglobin rise, and response outcomes. The registry record does not report results for those secondary measures in the registry record, nor does it report a statistical analysis plan specifying how each outcome was tested or summarized.

Multiplicity arises when multiple outcomes or hypotheses are examined. In general, the more statistical tests conducted, the greater the chance that at least one result appears noteworthy by chance if each test is assessed without accounting for the number of tests. Methods for addressing multiplicity can include designating a primary outcome, adjusting significance thresholds, or using a hierarchical testing sequence. The registry record does not report whether any such approach was prespecified or used. No adjustment method should be inferred from the listing of a primary endpoint.

Missing-data handling is also not reported in the registry record. The primary population is described as participants who completed the study, but the number completing it, the handling of participants without a Day 24 measurement, and any imputation or sensitivity analyses are not reported. A completed-study population may differ from all enrolled participants; without the relevant counts and analysis details, the extent and consequences of any such difference cannot be assessed.

The record does not report whether analyses were intention-to-treat, per-protocol, or based on another population definition. It also does not describe exclusions, adherence rules, or how treatment discontinuation affected endpoint inclusion. These omissions limit assessment of potential bias and reproducibility. They do not establish that the investigators failed to conduct these procedures; they mean the procedures are not reported in the registry record.

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: respiratory failure (19.4%), acute kidney injury (6.5%), hypoxia (6.5%), febrile neutropenia (3.2%), cardiac arrest (3.2%).

The registry lists safety figures for the Supportive Care (Eltrombopag Olamine) group. It records 31 at risk for serious adverse events and 14 affected, 31 at risk for other adverse events and 25 affected, and 8 deaths. These are registry counts, not a comparison between treatment groups. The record does not provide a concurrent control group against which to assess them.

The listed serious-event terms and percentages are respiratory failure, 19.4%; acute kidney injury, 6.5%; hypoxia, 6.5%; febrile neutropenia, 3.2%; cardiac arrest, 3.2%; and supraventricular tachycardia, 3.2%. The record does not state the denominator or additional calculation details for each percentage in the registry record. These terms should therefore be read as selected registry entries, not as a complete account of all events or as mutually exclusive categories.

In general, adverse-event counts describe events recorded during a study; they do not by themselves establish causation. The registry figures do not show whether events occurred before or after treatment, how long participants were exposed, or whether a participant could contribute to more than one category. The deaths entry is a count and should not be interpreted as evidence that treatment caused those deaths. The record does not report a comparative safety analysis.

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

The study registration describes an investigation of eltrombopag olamine during remission-induction chemotherapy for older patients with AML, with platelet recovery as its central question. It specifies a single-group phase II design and a primary threshold endpoint: the number of participants with a median platelet count >= 50,000/uL on Day 24 of treatment. The registry record does not report the observed primary endpoint result. It consequently does not establish how many participants met that criterion or how precise any estimate might be.

Even if a descriptive primary result were available, a single-group study would not supply a direct comparison with participants receiving an alternative strategy. Without a concurrent control group, differences attributable to treatment cannot be separated from other influences on recovery. The study design therefore does not support a randomized estimate of the treatment's effect. The registry record also does not report an adjusted comparative analysis.

The safety entries describe serious adverse events, other adverse events, deaths, and selected serious-event terms. These figures document events recorded in the treatment group; they do not establish that eltrombopag caused them. Nor do they allow a comparative safety conclusion, because no like-for-like control arm is registered. The record does not report the detail needed to evaluate event timing, exposure, or overlap.

The registry names several secondary outcomes, but their results are not reported in the registry record. Listing an outcome does not show that the outcome improved, worsened, or was unchanged. Likewise, the existence of planning assumptions does not demonstrate that the study had a particular probability of detecting an effect. Planning illustrations are conditional calculations, not observed power, and do not replace reported outcome estimates.

Accordingly, the record supports conclusions about what the study set out to examine and how the intervention and endpoint were defined. It does not support a conclusion about the observed primary outcome, a causal treatment effect, or a comparative safety profile. Those distinctions are essential when interpreting a registered single-group study with outcomes that are not numerically reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between an outcome definition and an outcome result. The registry clearly identifies a platelet-count threshold and a Day 24 assessment, but does not report the number meeting the threshold. A well-defined endpoint is necessary for interpretation; it is not a substitute for the observed estimate, denominator, or measure of uncertainty.

The single-group design also makes the distinction between description and causal inference especially important. A count of participants meeting a recovery criterion could describe the study population. Without a concurrent comparator, it would not show how outcomes differed under another treatment strategy. This is a general limitation of uncontrolled designs, not a judgment about the clinical importance of platelet recovery.

The registered population for the primary outcome is participants who completed the study, while the number completing it and missing-outcome procedures are not reported in the registry record. This highlights why analysis-population definitions matter: readers need to know who contributed to an estimate and how unavailable measurements were handled. Without those details, the potential influence of missing data cannot be assessed.

The listed safety figures also illustrate the limits of descriptive counts. Serious and other adverse-event entries can convey what was recorded in the group, but they cannot establish treatment causation or provide a controlled comparison. Percentages attached to selected terms require attention to their denominator and collection context, which are not fully described in the registry record.

Finally, planning calculations should not be confused with evidence observed in the study. The stated assumptions describe illustrations under a hypothetical two-arm framework; the registered trial itself is single group. Keeping design, planning, and observed results distinct prevents a planning convention from being mistaken for a trial result.

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 primary limitation for statistical interpretation is that the registry record does not report the primary endpoint result. It also does not report the denominator used for that endpoint or the number of participants who completed the study, despite defining the outcome population as participants who completed the study. The primary estimate and its precision therefore cannot be assessed.

The study is single group, with allocation not applicable and no masking. There is no concurrent control group in the registry description, so the design cannot provide a randomized comparison. Any outcome observed in the treatment group would be open to influences that cannot be distinguished from treatment effects using this design alone.

The intervention rule and outcome timing are stated, but detailed eligibility criteria, chemotherapy regimen, baseline characteristics, adherence, and the handling of treatment discontinuation are not reported in the registry record. The record does not report missing-data procedures, an analysis-population specification beyond the completer description, or sensitivity analyses. These omissions prevent readers from evaluating how exclusions or unavailable measurements may have affected results.

The registry lists 14 outcome measures but reports 0 analyses. It does not report a statistical analysis plan, multiplicity strategy, confidence intervals, or results for the named secondary outcomes. Safety entries are descriptive and lack a concurrent comparison; the record also does not provide details on timing, exposure, or overlap of events. These limitations concern what can be assessed from the registry record and do not establish what procedures may have been conducted outside it.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Eltrombopag Olamine in Improving Platelet Recovery in Older Patients With Acute Myeloid Leukemia Undergoing Chemotherapy — NCT02071901.
• Registry record last updated 2026-08-07; status last verified 2026-04.
• Results first posted 2020-11-24.
• 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

The registry describes a completed phase II, single-group study sponsored by Case Comprehensive Cancer Center, with enrollment listed as 31. The study examined daily oral eltrombopag olamine for older patients with AML undergoing remission-induction chemotherapy. Treatment was to continue until platelet counts reached >= 50,000/uL or for 8 weeks, whichever came earlier, provided there was no unacceptable toxicity.

The primary outcome is the number of participants with a median platelet count >= 50,000/uL on Day 24 of treatment, among participants who completed the study. The observed result and the number completing the study are not reported in the registry record. The record names 14 outcome measures and lists 0 analyses. It also records safety counts and selected serious-event terms, without a concurrent control group. These entries support a description of the registered design and outcomes, but not a comparative treatment-effect conclusion.