Darbepoetin Alfa MDS Companion Protocol: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Darbepoetin Alfa MDS Companion Protocol (NCT02175277), a na phase 3 study. The primary outcome is Number of Participants With Treatment-emergent Adverse Events.

2. Clinical Question

The study’s stated purpose was to provide continued access to darbepoetin alfa after the end of the active treatment period in the MDS 20090160 study for participants who had continued to demonstrate benefit. It also aimed to describe the safety of longer-term use in this population. The registry record identifies myelodysplastic syndrome as the condition and darbepoetin alfa as the intervention.

The primary question addressed by the registered outcome is descriptive: how many enrolled participants experienced treatment-emergent adverse events during the defined observation period? The outcome covers events from the first dose through 30 days after the last dose, with a maximum treatment duration of 73 weeks. The record also reports counts for serious and other adverse events, alongside the number of deaths and selected serious-event terms.

This is not a question about whether darbepoetin alfa is more effective or safer than another treatment. There is no concurrent comparator group, and the record does not report an efficacy outcome. Enrollment was limited to participants who had continued to demonstrate benefit in the earlier study, so the study population is defined by that prior treatment context. The registry record does not report further eligibility details or a broader target population.

3. Trial Design

NCT02175277 is a Phase 3, single-group study with no masking. Its allocation is recorded as not applicable, consistent with the absence of a randomized comparison. The registry lists 9 enrolled participants and identifies Amgen as the sponsor. The study began on 2014-06-12, reached primary completion on 2017-03-20, and is recorded as completed.

Participants received darbepoetin alfa for up to 73 weeks or until progression to acute myeloid leukemia, whichever occurred first. The stated purpose was to provide required access to the investigational product beyond the end of the active treatment period of the earlier darbepoetin alfa MDS 20090160 study for participants who continued to demonstrate benefit. The study also aimed to describe safety during longer-term use.

The primary outcome is a count of participants with treatment-emergent adverse events, rather than a comparison between randomized groups. The registry names all enrolled participants as the outcome population. Adverse events were graded using CTCAE version 4.0. Seriousness was defined by specified criteria including fatality, life-threatening events, hospitalization, persistent or significant disability, congenital anomaly or birth defect, and other medically important serious events. Investigators assessed whether each event was related to darbepoetin alfa.

The record lists 1 outcome measure and 0 analyses. It does not report the protocol’s statistical analysis plan, any prespecified precision target, or a sample-size justification. Because there is no control group, results describe the observed experience in the enrolled group and cannot isolate treatment effects from the underlying condition, prior selection, or other factors.

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: This study enrolled participants who completed the active treatment period of the phase 3 Study 20090160 (NCT01362140).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All enrolled participants

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 Participants With Treatment-emergent Adverse Events, measured over From first dose of darbepoetin alfa to 30 days after last dose; the maximum treatment duration was 73 weeks..

The primary endpoint is the number of participants with treatment-emergent adverse events. The registry defines the observation period as beginning with the first darbepoetin alfa dose and ending 30 days after the last dose; maximum treatment duration was 73 weeks. The measure counts participants with an event, rather than reporting the total number of event episodes.

Adverse-event severity was graded according to CTCAE version 4.0. The record describes Grade 1 as mild, Grade 2 as moderate, Grade 3 as severe or medically significant but not immediately life-threatening, and Grade 4 as involving life-threatening consequences for which urgent intervention was indicated. Seriousness is a separate classification: an event could meet a serious criterion based on its consequences or medical importance. The investigator assessed each event’s relationship to darbepoetin alfa.

A participant-count endpoint is useful for describing how many people in the enrolled group experienced an event during the specified period. It does not by itself indicate how many episodes occurred, how long events lasted, or whether an event was caused by treatment. Those questions require additional information and analyses. The registry’s primary measure focuses on participants with events; it is a safety description, not an estimate of comparative risk because the study has no comparator group.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry presents a single-group safety outcome as a participant count. In this design, the main descriptive quantity is the number of participants recorded with an event, interpreted alongside the number at risk. The posted results give both counts for serious and other adverse events. They do not present a treatment-versus-control contrast, since there is no comparator arm.

What does a participant count represent?

A participant count answers how many people in the outcome population experienced at least one event in the relevant category. It is distinct from an event count: repeated episodes in one person do not necessarily increase the number of participants with an event. Participant counts are often useful for a basic safety description, but they do not capture every feature of event burden. The registry does not report episode counts, event duration, or a participant-level listing.

How should serious and other events be distinguished?

Severity and seriousness describe different aspects of an adverse event. Severity in this record was graded using CTCAE version 4.0, whose listed grades range from mild through life-threatening consequences. Seriousness was defined by criteria such as fatality, life-threatening status, inpatient hospitalization or its prolongation, persistent or significant disability, congenital anomaly or birth defect, and other medically important events. Thus, a serious-event count is not simply a count of events above a particular severity grade. The record does not provide a cross-tabulation of seriousness and severity.

Why does the design affect interpretation?

A single-group study can describe what was observed among people receiving the intervention, but it cannot directly estimate a contrast with an alternative. In a randomized controlled comparison, allocation can support a comparison between groups under the design’s assumptions. Here, allocation is not applicable and masking is absent. The reported counts therefore remain descriptive. They cannot separate treatment-related events from events that might occur because of the condition, prior care, or other circumstances.

Selection is also relevant. The stated purpose concerned access for participants who continued to demonstrate benefit in the earlier study. This defines a selected treatment context. Generalizing the observed safety experience beyond this group requires caution; the registry does not report information that would establish representativeness of a broader population.

What uncertainty information is available?

The record gives counts and selected serious-event terms, but no confidence intervals, p-values, or model-based estimates. A confidence interval is a general statistical way to express the range of values compatible with data under a specified method and assumptions. Without a reported interval or analysis method, the precision of the event estimates is not stated. Counts should not be mistaken for exact underlying risks, especially when the enrolled group is small.

Over-dispersion is a general concern when variation in event counts is greater than a model assumes. It is particularly relevant to analyses of episode counts, where some participants may have repeated events. The primary registered measure is a count of participants with events, and the record does not report an episode-count model or any analysis addressing over-dispersion. No such modeling result can be inferred.

What is known about sample-size planning?

The record does not report a trial-specific sample-size justification. It includes general assumptions for planning illustrations based on an observed effect, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions describe illustrations, not the design of this single-group study, and no calculated planning counts are reported in the registry record. Such illustrations are not observed power and should not be read as the trial’s own enrollment rationale.

The record lists 0 analyses. It does not report an inferential statistical plan, a confidence-interval method, adjustment for covariates, or an interim-analysis plan. Accordingly, interpretation should remain with the reported safety counts and the design context, rather than imply a statistical comparison or estimation procedure that is not documented.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 1 outcome measure and 0 analyses. The record does not report a plan for controlling multiplicity, such as a hierarchy of outcomes or an adjustment for multiple statistical tests. Since no inferential analyses are registered, the posted information does not establish that hypothesis testing was conducted. The primary outcome is a safety measure; the selected serious-event terms add descriptive detail but are not accompanied by a reported testing framework.

Missing-data methods are not reported in the registry record. It does not explain how participants with incomplete follow-up, missing event information, or differing exposure duration were handled. The arm results give 9 at risk for serious and other adverse events, but that alone does not describe completeness of follow-up for every participant or how missing observations, if any, were treated.

The registered outcome population is all enrolled participants. The record does not report a separate safety analysis population, exclusions from analysis, or an approach to participants who stopped treatment early. Nor does it state whether outcome data were analyzed according to a prespecified rule. These omissions limit assessment of how the reported counts were assembled and how they relate to the full enrolled population.

These are documentation gaps, not evidence that a particular method was or was not used. The relevant procedures are not reported in the registry record, so no assumptions about imputation, censoring, multiplicity adjustment, or interim review should be made.

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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: macular fibrosis (11.1%), pyrexia (11.1%), ischaemic stroke (11.1%).

The safety results report 3 participants with serious adverse events among 9 at risk, 9 participants with other adverse events among 9 at risk, and 0 deaths. The serious-event terms listed as most frequent are Macular fibrosis, Pyrexia, and Ischaemic stroke, each reported as 11.1%.

These figures describe participants recorded with events during the study’s safety observation period, which ran from first dose to 30 days after last dose; maximum treatment duration was 73 weeks. They are not a comparison with a control group. The percentages attached to the serious-event terms do not establish causality, and the registry record does not report the relatedness assessments for those terms. An investigator assessed whether each adverse event was related to darbepoetin alfa, but the corresponding judgments are not given in the posted results.

Participant counts do not equal event episodes, and the listed terms do not describe duration, severity, or timing. The record defines seriousness using clinical criteria and separately describes CTCAE severity grades. A serious-event count should therefore be read as a descriptive safety finding under the registry definitions, not as a complete account of the burden or cause of adverse events.

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

The results establish what was recorded in this enrolled group during the stated treatment and follow-up period: 3 participants had serious adverse events, 9 had other adverse events, and 0 deaths were recorded. The registry also identifies three serious-event terms with values of 11.1% each. These findings are relevant as a descriptive account of longer-term exposure in the study’s selected population.

They do not establish that darbepoetin alfa caused any particular event. The registry says investigators assessed relatedness, but the posted information does not give those assessments. A temporal event during treatment is not, by itself, proof of a causal relationship. Similarly, the absence of a recorded death in this group does not establish that the risk of death is absent in other populations or settings.

The design also limits what can be concluded. With no concurrent comparator, the event counts cannot show whether safety outcomes were more or less common than under another treatment or no treatment. The study does not report an efficacy endpoint in this record, so the results do not answer an effectiveness question. The participants were included in a companion study after continued demonstration of benefit in the earlier study; the safety observations should be understood in that context rather than generalized automatically to all people with myelodysplastic syndrome.

No confidence intervals or statistical comparisons are reported. The counts are therefore best read as observed results, without a registry-reported estimate of precision. The record also does not describe missing-data handling, the full analysis procedures, or the extent of follow-up for each participant. Those details matter when assessing how completely the observed counts represent the intended population and observation period.

In short, the record documents adverse events in a single-group cohort and supplies context about event definitions and exposure. It does not provide a controlled estimate of treatment-attributable risk, a causal conclusion, or a comparative benefit-risk assessment.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between describing outcomes and estimating comparative effects. A single-group study can record adverse events during exposure and provide counts within a defined population. It cannot, on its own, determine how those outcomes differ from a suitable control condition. The absence of a comparator is central to interpretation, not a technical detail that can be remedied by treating the observed counts as a treatment contrast.

The population and purpose also shape the estimand. The study was intended to provide continued access for participants who continued to demonstrate benefit in an earlier study, while describing longer-term safety. The resulting observations address that specific context. They do not automatically represent all people with myelodysplastic syndrome, nor do they answer a separate efficacy question.

Endpoint definitions are important in safety reporting. The primary outcome counts participants with treatment-emergent adverse events, while seriousness and CTCAE severity refer to distinct classifications. Keeping those concepts separate helps avoid interpreting a serious-event count as a complete severity profile or as a count of all event episodes. The posted information supports a concise description of who experienced events, but not a complete account of event burden.

Finally, this record illustrates why statistical documentation matters. It reports counts but not confidence intervals, missing-data procedures, multiplicity handling, or a trial-specific sample-size justification. Without those details, readers can describe the observed safety experience but cannot assess several aspects of precision and analysis conduct. The appropriate statistical conclusion is therefore bounded: a safety description is available, while comparative and causal claims are not.

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 single-group design. There is no concurrent comparator, and the registry lists allocation as not applicable. Consequently, the study cannot estimate a relative treatment effect or separate treatment-associated events from events related to the condition, prior care, or other factors. Lack of masking is also recorded; the registry does not describe whether outcome assessment involved procedures intended to reduce the influence of this design feature.

The enrolled population was defined in relation to continued benefit in the earlier MDS 20090160 study. This selection limits how readily the findings can be extended to people outside that treatment context. The registry record does not provide further eligibility criteria or demographic and clinical detail needed to assess representativeness.

The outcome is a participant count. It does not provide event episode counts, duration, timing, or a full severity distribution. Although investigators assessed whether events were related to darbepoetin alfa, the posted results do not report those assessments. The selected serious-event terms likewise do not establish attribution.

The record does not report confidence intervals, hypothesis tests, a statistical analysis plan, missing-data methods, an analysis population beyond all enrolled participants for the primary outcome, or a trial-specific sample-size justification. It also does not state how incomplete follow-up or early treatment discontinuation affected the reported counts. These gaps make precision and analysis procedures difficult to assess. The maximum treatment duration was 73 weeks, but the registry does not give individual exposure durations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Darbepoetin Alfa MDS Companion Protocol — NCT02175277.
• Registry record last updated 2018-11-14; status last verified 2018-10.
• Results first posted 2018-10-11.
• 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

NCT02175277 is a completed Phase 3, single-group study sponsored by Amgen, with 9 participants enrolled. It evaluated darbepoetin alfa in participants with myelodysplastic syndrome in a companion-study context intended to provide continued access after the active treatment period of the earlier study and describe longer-term safety.

Participants received darbepoetin alfa for up to 73 weeks or until progression to acute myeloid leukemia, whichever occurred first. The primary outcome was the number of participants with treatment-emergent adverse events from first dose through 30 days after last dose. The posted results report 3 participants with serious adverse events, 9 with other adverse events, and 0 deaths.

The record provides no comparator, lists 1 outcome measure and 0 analyses, and does not report confidence intervals, a statistical analysis plan, missing-data procedures, or a trial-specific sample-size justification. Results are descriptive and do not provide a controlled estimate of treatment effect or event causality.