Epoetin Alfa in Treating Patients With Anemia Who Are Undergoing Chemotherapy for Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Epoetin Alfa in Treating Patients With Anemia Who Are Undergoing Chemotherapy for Cancer (NCT00258440), a randomized na study. The primary outcome is Number of Subjects That Maintained Target Hemoglobin Level (11-12 g/dL) Maintenance Weekly for 12 Weeks.

2. Clinical Question

The trial was a pilot study of extended-interval epoetin alfa dosing in oncology patients with anemia. Its stated purpose was to study how well epoetin alfa works in patients receiving cancer chemotherapy, while the posted primary outcome specifically concerns maintenance of the target hemoglobin range. The record also identifies pharmacokinetic and pharmacodynamic assays, quality of life, and adverse events as secondary outcomes. These additional aims describe what the trial intended to assess; they do not establish that complete results for each outcome were available.

3. Trial Design

The registry describes a randomized, parallel-group trial with no masking. It lists the phase as NA and the enrollment as 7. The sponsor was OHSU Knight Cancer Institute. The record lists a start date of 2003-05, a primary completion date of 2008-09, and a status of terminated. The official title describes the study as a pilot trial of extended-interval epoetin alfa dosing for anemia in oncology patients.

One arm used weekly Procrit (epoetin alfa), with participants receiving the study drug once every week until the end of the study. The interval-dosing schedule began with weekly treatment and changed to once every other week after hematocrit was greater than 36% or hemoglobin reached 12 g/dl. The interval schedule was represented by a pharmacokinetic group, whose members consented to pharmacokinetic testing, and a non-pharmacokinetic group, whose members did not consent to that testing.

The posted arm counts are 1 for weekly dosing, 0 for the interval pharmacokinetic group, and 6 for the interval non-pharmacokinetic group. These counts account for the enrollment of 7, but the posted record does not explain how randomization was conducted or how allocation among the groups was determined. The number assigned to each group was not balanced in the posted results, and there were no participants represented in the pharmacokinetic group.

The registry lists four outcome measures, including the primary outcome and three secondary outcomes. The secondary outcomes concern serum erythropoietin concentration, quality of life, and adverse events. The record reports no analyses. Details such as the randomization sequence, allocation concealment, planned sample-size justification, and a complete statistical analysis plan 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Due to low accrual numbers and the discontinuation of the study early a full analysis was not completed.

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 Number of Subjects That Maintained Target Hemoglobin Level (11-12 g/dL) Maintenance Weekly for 12 Weeks, measured over 12 weeks.

The primary outcome is the number of participants who maintained a target hemoglobin level of 11-12 g/dL on a weekly basis for 12 weeks. It is a count of participants, rather than a measure of the amount by which hemoglobin changed. The intended target range and repeated maintenance criterion define what counted as meeting the outcome in the registry description.

A maintenance outcome can address whether participants remained within a prespecified clinical range over a defined period, rather than whether they reached a value at a single assessment. That makes the measure relevant to the trial's question about an extended-interval dosing schedule. This is a general explanation of the endpoint concept; the registry does not report additional details about how measurements were collected, how missing weekly assessments were handled, or how maintenance was adjudicated.

The primary outcome description states that low accrual and early discontinuation meant a full analysis was not completed. The posted arm entries list a value of 0 for weekly dosing, a value of 5 for interval non-pharmacokinetic dosing, and no value for the interval pharmacokinetic group. The weekly entry also has accompanying lower and upper values of 1.0 and 6.0; their meaning is not explained in the record. Those entries should not be read as a completed comparison or as a complete account of endpoint maintenance across the randomized groups.

Why use this endpoint? A participant count is straightforward to interpret as the number recorded as meeting the maintenance criterion. However, without a completed analysis, information about the outcome definition's implementation, and a comparative estimate with uncertainty, the count entries alone do not establish how the schedules compare.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Randomization is intended to make treatment assignment less dependent on participants' characteristics, supporting a fair comparison between assigned groups. This is a general statistical principle. The registry identifies the trial as randomized and parallel, but does not report the sequence-generation method, allocation concealment, or the allocation procedure. The posted counts are highly uneven, and no participants appear in the interval pharmacokinetic group. With so few observations, random assignment alone cannot ensure that the groups are comparable in all relevant characteristics.

What does a count endpoint mean?

The primary outcome is a number of participants meeting the hemoglobin maintenance criterion. For a binary outcome at the participant level, each person is classified as meeting or not meeting the criterion, and the arm result can be described as a count. This is a general explanation. The posted outcome is a count, but the record says that a full analysis was not completed and does not explain how missing weekly assessments or incomplete follow-up affected classification. The listed arm entries are therefore not enough to reconstruct a complete comparative analysis.

Why is uncertainty important?

An estimate based on a small number of participants is typically imprecise. A confidence interval is a statistical range that communicates uncertainty around an estimate under the assumptions of the analysis. It does not guarantee that the true value falls within that range, but it helps readers distinguish a precise estimate from one compatible with a broad range of effects. The registry does not report a confidence interval or another comparative uncertainty measure for the primary outcome. The primary outcome description also states that a full analysis was not completed. Consequently, the degree of uncertainty around any comparison is not quantified in the record.

How should the group structure be understood?

The interval schedule is split into a pharmacokinetic group and a non-pharmacokinetic group according to consent for pharmacokinetic testing. That distinction concerns testing participation as well as the shared interval dosing schedule. It is not a separate randomized treatment comparison in the posted record. The pharmacokinetic group has a posted count of 0, so no within-trial pharmacokinetic group result can be interpreted from the arm data. The non-pharmacokinetic group has a posted count of 6. The record does not describe how consenting to testing was incorporated into randomization or the statistical analysis.

What do the analysis fields tell us?

The registry lists zero analyses. It does not post an inferential result for the primary outcome, such as a treatment contrast, p-value, or confidence interval. Those absences limit statistical interpretation: descriptive arm entries cannot answer whether the schedules differ, and they do not quantify precision. The record also does not report a planned statistical model, an adjustment strategy, interim analyses, or a protocol-defined method for handling missing data. These details should not be inferred from the fact that the study was randomized.

What is a planning sample-size calculation?

A sample-size calculation is a planning exercise that estimates how many participants would be needed to detect an effect under stated assumptions. The registry's planning description specifies a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect framed as a stated fraction of the observed effect. Such calculations are illustrations, not evidence about the trial's achieved ability to detect an effect. They are not observed power, and they do not repair the absence of a completed analysis. The record does not report the trial's own design justification or target enrollment, so the planning description should not be mistaken for the original protocol's rationale.

In general, a statistical test assesses how compatible data are with a specified null hypothesis under a model; a p-value, when reported, is not the probability that the null hypothesis is true. No p-value is reported for the primary comparison. The record also does not report whether any adjustment for multiple outcomes was planned. Because only descriptive information is available for the primary endpoint, it is more appropriate to emphasize the incomplete analysis and limited precision than to infer a statistical conclusion from the raw entries.

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("Weekly Procrit (Epoetin Alfa) Dosing", "Interval Dosing (Epoetin Alfa) Non PK Group")
n      <- c(1, 6)
events <- c(0, 5)
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  Weekly Procrit (Epoetin Alfa) Dosing  1  0  0.0  0.0  97.5  0.0  79.3  1.3  84.2
ARM  Interval Dosing (Epoetin Alfa) Non PK Group  6  5  83.3  35.9  99.6  43.6  97.0  42.1  96.3

11. Multiplicity, Missing Data and Analysis Populations

The record identifies four outcome measures: the primary hemoglobin maintenance count and three secondary outcomes. The secondary outcomes concern serum erythropoietin concentration through pharmacokinetic and pharmacodynamic assays, quality of life at baseline and Weeks 4, 8, 16, 24, and 28, and the number of adverse events as a measure of safety and tolerability. The record lists no analyses. It does not report whether the outcomes were organized into a hierarchy, whether a multiplicity adjustment was planned, or which secondary comparisons were intended to support formal inference. Without that information, the risk of drawing a chance-positive conclusion across multiple outcomes cannot be evaluated.

The primary outcome description says that a full analysis was not completed because of low accrual and early study discontinuation. Details on missing data are not reported in the registry record: there is no posted description of the amount or pattern of missingness, how missing measurements were handled, or whether participants were analyzed according to randomized assignment. These omissions matter for an outcome requiring weekly maintenance across 12 weeks, because incomplete measurements can affect whether a participant can be classified as having maintained the target.

The record also does not report a defined analysis population, such as an intention-to-treat or per-protocol population, or any rules for excluding participants. The posted group counts show 1 participant in weekly dosing, 0 in the interval pharmacokinetic group, and 6 in the interval non-pharmacokinetic group, but do not explain how those counts relate to eligibility, consent, randomization, or the analysis set. Therefore, the available entries should be read as incomplete descriptive information rather than a complete account of all randomized participants and outcomes.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

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: failure to thrive, gi bleed, malignant hypercalcemia (16.7%), fever neutropenia (16.7%).

The registry reports serious adverse event figures by group. For weekly Procrit dosing, it lists 1 participant at risk and 0 affected. For the interval pharmacokinetic group, it lists 0 at risk and 0 affected. For interval non-pharmacokinetic dosing, it lists 6 at risk and 1 affected. These are descriptive counts from a very small trial; they do not establish a comparative safety profile. The group with no participants cannot contribute an observed safety comparison.

The record also lists other adverse event figures: 1 participant at risk and 1 affected in the weekly group, none in the interval pharmacokinetic group, and 6 at risk and 6 affected in the interval non-pharmacokinetic group. The serious-event term list includes “Failure to thrive, GI bleed, Malignant Hypercalcemia” and “Fever Neutropenia,” each accompanied by 16.7%. The record does not clearly identify the group attribution for those terms. Death counts are not reported in the registry record.

These figures should be interpreted cautiously. The record does not provide a complete explanation of event collection, observation time, or missing safety information. Small counts can change substantially with a small number of additional observations, and a descriptive count is not a test of whether groups differ. The listed adverse events neither establish nor rule out a safety difference between schedules.

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

The posted results document a randomized pilot trial of weekly and interval epoetin alfa dosing in patients with anemia undergoing chemotherapy for cancer. The primary outcome concerned the number of participants maintaining a hemoglobin level of 11-12 g/dL weekly for 12 weeks. The record reports that low accrual and early discontinuation prevented a full analysis. The posted enrollment was 7, with 1 participant in the weekly group, 0 in the interval pharmacokinetic group, and 6 in the interval non-pharmacokinetic group.

These registry entries do not establish whether one dosing schedule was more effective than the other. The primary outcome entries are incomplete, no comparative estimate or measure of uncertainty is reported, and the record lists no analyses. The weekly entry's accompanying lower and upper values are not explained. The posted count of 5 for the interval non-pharmacokinetic group cannot by itself be interpreted as a valid comparative effect, especially when there is no posted value for the pharmacokinetic group and the record states that a full analysis was not completed.

The results also do not establish equivalence between schedules. A lack of a reported statistical comparison is not evidence that the schedules produce the same outcomes. Nor do these entries establish that either schedule works or does not work. They describe a limited set of registry-reported observations, without the analysis and precision needed to draw a reliable comparative conclusion.

The secondary outcomes and adverse event counts have similar limits. They identify areas the trial intended to assess, but the registry record does not contain a complete analysis of those outcomes. Safety figures are descriptive and arise from very small groups, including an interval pharmacokinetic group with no participants. They should not be treated as evidence that adverse events are more or less likely under either schedule.

In short, the record is informative about the trial's question, design, early termination, and the counts posted for its groups. It does not resolve the comparative clinical question. The record does not report the reasons for termination, a complete statistical analysis plan, a sample-size justification, or a full account of missing outcome data. Those gaps, along with low accrual, limit the conclusions that can be drawn from the posted results.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the difference between a randomized design and a conclusive randomized comparison. Randomization is an important design feature, but it cannot compensate for very low enrollment, a group with no participants, or an incomplete primary outcome analysis. The record lists enrollment of 7 and states that low accrual and early discontinuation prevented a full analysis. These features leave the central comparative question unresolved.

The primary outcome is a participant count tied to a defined hemoglobin range and a 12-week maintenance period. Such an endpoint can be clinically interpretable when its classification rules and follow-up are complete. In this record, the outcome entries are partial and the meaning of some accompanying fields is not explained. The contrast between a stated endpoint and an incomplete analysis is a reminder that an endpoint definition alone does not supply the evidence needed to assess an intervention.

The study also shows why uncertainty and missing-data methods matter. Without a completed analysis, comparative estimate, or uncertainty interval, readers cannot tell how much the posted results support any treatment contrast. Missing-data handling and analysis populations are not described. Those are not merely technical details: they help define which participants and observations contribute to an estimate.

Finally, this record separates planned assessment from analyzable evidence. It lists pharmacokinetic, quality-of-life, and safety outcomes, but the posted information does not include a complete analysis of them. A registry record can make the research question and design visible while still leaving the results too limited to support a firm statistical conclusion. Here, the useful lesson is to distinguish what was intended, what was recorded, and what the available data can actually establish.

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.

Several trial-specific limitations constrain interpretation. Enrollment was 7, and the study status is terminated. The primary outcome description directly attributes the incomplete analysis to low accrual and early discontinuation. The record does not report the reason for termination or the intended enrollment target, so it is not possible to assess whether the observed enrollment was close to the planned sample size.

The group counts are 1 for weekly dosing, 0 for interval dosing in the pharmacokinetic group, and 6 for interval dosing in the non-pharmacokinetic group. This distribution leaves no posted observations for the pharmacokinetic group and only one participant in the weekly group. The interval groups are distinguished by consent to pharmacokinetic testing, but the record does not explain how consent, randomization, or group assignment were related. Thus, the posted groups do not support a balanced or complete comparison.

The primary endpoint entry itself requires caution. It lists a value of 0 for the weekly group with accompanying values of 1.0 and 6.0, while the non-pharmacokinetic interval group has a value of 5 and the pharmacokinetic group has no value. The registry does not explain the meaning of the accompanying weekly values. The outcome description says a full analysis was not completed, so the entries should not be treated as a complete endpoint dataset.

The registry does not report a full analysis plan, randomization procedure, allocation concealment, analysis population, missing-data method, or sample-size justification. It also does not provide comparative estimates or uncertainty measures. Secondary outcomes and safety results are incomplete or descriptive, and the serious-event term list does not clearly identify group attribution. These limitations mean the record supports only a cautious description of the trial and its posted data, not a precise estimate of comparative effects.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Epoetin Alfa in Treating Patients With Anemia Who Are Undergoing Chemotherapy for Cancer — NCT00258440.
• Registry record last updated 2017-05-09; status last verified 2017-05.
• Results first posted 2011-05-26.
• 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.

19. Record Summary

NCT00258440, titled “Epoetin Alfa in Treating Patients With Anemia Who Are Undergoing Chemotherapy for Cancer,” was a randomized, parallel, unmasked pilot trial sponsored by OHSU Knight Cancer Institute. The registry lists phase NA, enrollment 7, a start date of 2003-05, primary completion in 2008-09, and terminated status.

The trial compared weekly Procrit (epoetin alfa) dosing with an interval schedule that changed from weekly to once every other week after hematocrit was greater than 36% or hemoglobin reached 12 g/dl. The primary outcome was the number of participants maintaining a target hemoglobin level of 11-12 g/dL weekly for 12 weeks. The registry states that low accrual and early discontinuation prevented a full analysis.

Posted arm counts are 1 for weekly dosing, 0 for interval dosing in the pharmacokinetic group, and 6 for interval dosing in the non-pharmacokinetic group. The record lists three secondary outcomes concerning serum erythropoietin, quality of life, and adverse events, but reports no analyses. The available outcome entries and safety counts are descriptive and do not establish a comparative treatment effect.