A Study of MK2578 in Patients With Chronic Kidney Disease Who Are Not on Dialysis (2578-002): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of MK2578 in Patients With Chronic Kidney Disease Who Are Not on Dialysis (2578-002) (NCT00968617), a randomized phase 2 study. The primary outcome is Change From Baseline in Hemoglobin Level at Week 4.

2. Clinical Question

The study was intended to examine the efficacy and safety of MK2578 in patients with chronic kidney disease who had not previously received an erythropoiesis-stimulating agent. Its brief summary says the study aimed to define an effective starting dose for MK2578 while evaluating safety. The listed dose groups make dose-level comparisons relevant, while the darbepoetin alfa group supplies an active comparator.

The registry record describes random allocation and a parallel-group design. In general, random allocation is used to reduce systematic differences between assigned groups, while a parallel design follows participants in their assigned groups rather than switching treatments. The record does not report the allocation ratio, the numbers assigned to each group, or the actual treatment received by each participant. With seven participants enrolled overall, the record does not permit a detailed assessment of how the groups compared.

The central clinical question is therefore clear at the level of the stated objective, but the posted record does not provide the outcome values needed to answer it. In particular, group-specific hemoglobin changes, measures of variability, and comparative estimates are not reported in the registry record. The study status is terminated; the reason for termination is not reported in the registry record.

3. Trial Design

The registry record identifies this as a Phase IIb randomized, active comparator-controlled, open-label clinical trial. It lists a parallel model and no masking. The population was ESA-naive patients with chronic kidney disease who were not on dialysis, and the stated purpose was to study MK2578 for anemia in that population. The listed interventions include three MK2578 dose groups and darbepoetin alfa as the comparator.

Randomization means that treatment assignment is intended to be determined by chance. In general, this design can help limit systematic differences between groups at the time of assignment, although it does not guarantee balance in a small study. The record does not describe the randomization sequence, allocation concealment, allocation ratio, or group-specific enrollment. Those details are not reported in the registry record.

The study was open-label, meaning treatment assignment was not masked from participants and study personnel as described in the design. Open-label designs can affect behaviors, treatment decisions, and assessments that involve judgment. Hemoglobin is a laboratory measure, but the record does not explain whether laboratory staff were masked or how measurements were collected and processed. Those details are not reported in the registry record.

The registry lists enrollment of 7 participants. It reports a start of 2009-11 and primary completion of 2010-04, and the overall status is terminated. The reason for termination, the date of termination, and whether the planned follow-up was completed are not reported in the registry record. The listed primary outcome is change from baseline in hemoglobin level at Week 4, measured in g/dL as a mean with standard deviation. Secondary outcomes include hemoglobin concentration after treatment with MK2578, change from baseline in hemoglobin level, and the number of participants who were responders. The registry lists nine outcome measures in total, but does not provide their results in the record summarized by these details.

The planned comparison structure and actual analysis cannot be fully reconstructed from the record. The analysis population, handling of withdrawals, and statistical model are not reported in the registry record. The record lists zero analyses, so it does not provide an inferential comparison for the primary endpoint.

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 in Cohorts 1 and 2 were to receive 1.0 mcg/kg/month and 2.0 mcg/kg/month, respectively, of MK2578. Participants in Cohort 3 were to be randomized to MK2578 3.6 mcg/kg/month or to weekly doses of darbepoetin alfa 0.45 mcg/kg/week. Cohort 1 was the only cohort initiated.

Overall Study

Reasons for not completing this period:

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 Change From Baseline in Hemoglobin Level at Week 4, measured over 4 weeks.

The primary endpoint is change from baseline in hemoglobin level at Week 4, expressed in g/dL. Hemoglobin is the blood measure named in the study outcome, and change from baseline describes how the follow-up value differs from a participant’s starting value. The record specifies that the endpoint is summarized as a mean and standard deviation. The outcome results themselves are not reported in the registry record.

In general, measuring change from baseline can focus the assessment on how much a participant’s measured value shifts during the study rather than relying only on the follow-up value. Baseline adjustment or change scores can also help account for differences in starting measurements, though the advantages depend on the analysis plan and data structure. The registry record does not explain whether the primary analysis used individual change scores, adjusted follow-up values, or another approach.

A mean describes the average change within a group. A standard deviation describes how dispersed individual measurements are around that group’s mean; it is not the same as uncertainty in the estimated mean. To assess the precision of a group comparison, readers would generally need an estimate of the between-group difference and a confidence interval, or another suitable measure of uncertainty. Neither these statistics nor group-specific endpoint summaries are reported in the registry record.

The four-week time point provides a defined early assessment of the stated outcome. It does not, by itself, describe the durability of a change or later outcomes. The registry record does not report a rationale for selecting this time point, the timing of baseline measurement, or the rules for measurements outside the target visit window. Therefore the endpoint’s definition is available, but its observed values and measurement procedures cannot be evaluated from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary endpoint summary mean?

The primary endpoint is a continuous measurement: change from baseline in hemoglobin level at Week 4, with units of g/dL. The registry specifies the mean and standard deviation as its summary statistics. In general, the mean is the arithmetic center of a set of measurements, while the standard deviation describes their spread around that center. A small standard deviation indicates that values are relatively clustered; a large one indicates more variation. Neither statistic is reported for the endpoint in the registry record.

The standard deviation should not be read as the precision of the estimated group mean. Precision depends in part on the number of observed participants and the variability in their measurements. A standard error or confidence interval can express uncertainty in an estimate, but neither is reported for the primary endpoint. The number enrolled overall is 7, but the number with an observed Week 4 value in each group is not reported in the registry record.

What can randomization establish?

Randomization assigns participants by chance to study groups. In general, this helps prevent treatment assignment from being systematically linked to participants’ measured or unmeasured characteristics. It does not ensure that groups will be identical, particularly in a small trial. The record confirms random allocation but does not report its implementation, the allocation ratio, concealment procedures, or group sizes.

The parallel design means participants are assigned to a group and assessed in that group over the study, rather than being described as crossing over between treatments. The record lists MK2578 dose groups of 1.0 mcg/kg, 2.0 mcg/kg, and 3.6 mcg/kg, plus darbepoetin alfa. It does not report whether each group enrolled participants or the number assigned to each. The record also does not provide a statistical model for comparing groups.

How should an open-label design be considered?

The study is described as open-label, with no masking. In general, knowledge of assigned treatment can affect participant behavior, concomitant care, decisions to stop treatment, and outcome assessment. A laboratory outcome may be less dependent on subjective judgment than a symptom rating, but collection, timing, handling, and missingness can still matter. The registry record does not describe masking of laboratory personnel or the procedures used to obtain hemoglobin measurements.

What would a treatment comparison require?

A comparative analysis would ordinarily report a contrast between groups, such as a difference in mean change, together with a measure of uncertainty. The interpretation depends on the analysis population, the treatment groups included, and assumptions about the data. The registry record does not report a comparative estimate, confidence interval, p-value, or analysis method. It lists zero analyses, so there is no inferential result to interpret.

In general, a confidence interval conveys the range of effect estimates reasonably compatible with the observed data under the model used. A narrow interval indicates greater precision than a wide interval, though interval interpretation also depends on design and analysis assumptions. Statistical significance and clinical relevance are distinct: an estimate can be precise but small, or large but uncertain. The record contains no interval or effect estimate from which to make either assessment.

Why can variability matter?

For continuous outcomes, variation among participants affects how precisely a group mean or group difference can be estimated. If data vary more than an analysis model assumes, standard errors may be underestimated and intervals or tests may be unreliable. In general, over-dispersion means that observed variability exceeds what a statistical model anticipates; it can call for an analysis that accounts for the extra variability. The primary endpoint is continuous and the stated summary includes a standard deviation, but no observed standard deviation or model is reported in the registry record. There is therefore no basis to diagnose over-dispersion in this study.

How should planning calculations be distinguished from trial results?

Sample-size planning illustrations are not observed treatment effects or evidence that a trial had a particular probability of detecting an effect after the data were collected. The registry record describes a planning approach using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a fraction of an observed effect. These assumptions describe a planning illustration, not a reported design justification. The numerical planning results and a sample-size justification for the trial are not reported in the registry record.

In general, calculations based on an observed effect can be sensitive to uncertainty in that effect, and a sample-size illustration does not replace an analysis of observed data. It should not be described as observed power. The record does not report the effect estimate on which the planning illustration was based, nor the trial’s own sample-size rationale. Since the posted endpoint results are also absent, the planning description cannot be used to infer the study’s findings.

What is available for safety interpretation?

The record gives counts for one safety group titled MK-2578. The serious adverse event count is zero among seven participants at risk; the other adverse event count is four among seven at risk. In general, counts describe how many participants experienced an event, while denominators clarify the number considered at risk for that outcome. Such counts do not establish comparative risk when corresponding group data and analysis are unavailable. The record does not list serious event terms, and a death count is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists nine outcome measures, including the primary change-from-baseline endpoint and several secondary outcomes. When a study evaluates multiple outcomes, time points, doses, or pairwise comparisons, the chance of at least one apparently unusual result can increase if every comparison is treated as a separate confirmatory test. In general, statistical plans may address multiplicity by identifying a primary endpoint, specifying a testing sequence, or adjusting inference. The record does not report a multiplicity strategy, hierarchy among secondary outcomes, or which comparisons were intended to be confirmatory.

The primary endpoint is identified as change from baseline in hemoglobin level at Week 4. That designation helps distinguish the main stated outcome from secondary measures, but does not establish how the study handled testing across three MK2578 dose groups and darbepoetin alfa. Planned contrasts and any correction for multiple comparisons are not reported in the registry record. No analysis results are reported, so the effect of any multiplicity procedure cannot be assessed.

Missing-data methods and analysis populations are also not reported in the registry record. The record does not state how participants without a Week 4 measurement were handled, whether incomplete observations were imputed, or whether the analysis used all randomized participants or another population. These choices can affect a treatment comparison, especially if missingness differs across groups or is associated with outcomes.

Although enrollment is listed as 7, the record does not provide group-specific enrollment or endpoint completion. It is therefore not possible to determine from the record how many participants contributed to each outcome, whether all randomized participants were analyzed, or how missing values may have influenced the estimates. No statistical plan, interim analysis description, or sample-size justification is reported in the registry record.

11. 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 non-serious adverse event terms

The safety record lists one group titled MK-2578, with seven participants at risk. It reports zero participants affected by serious adverse events and four affected by other adverse events. These are participant counts, not event counts: the record does not say how many separate events occurred in the affected participants. Serious adverse event terms are not listed.

The figures are descriptive and should not be treated as a comparison between MK2578 and darbepoetin alfa. Safety data for the comparator group are not reported in the registry record, and the listed MK-2578 group does not distinguish the three dose groups. The record also does not provide event timing, severity details for other adverse events, or information about relatedness to study treatment.

The death value is null; a death count is therefore not reported in the registry record. Zero reported serious adverse events in the listed group is a count for the seven participants at risk, not evidence that serious events are impossible or that the treatment is safer than the comparator. With the information available, the record supports only the limited description of these reported counts, not a comparative safety estimate or a broader conclusion about risk.

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

The registry record documents a randomized, open-label study intended to examine MK2578 in ESA-naive patients with chronic kidney disease who were not on dialysis. It identifies three MK2578 dose groups, darbepoetin alfa as an active comparator, a Week 4 hemoglobin change endpoint, and enrollment of 7 participants. These details describe the study question and structure, not its treatment effect.

The result does not establish whether hemoglobin changed in any group or whether the groups differed. The primary endpoint results, group-level summaries, comparative estimate, confidence interval, and p-value are not reported in the registry record. The record also lists zero analyses. Consequently, neither an effect size nor the precision of any estimate can be assessed from the posted results.

The study status is terminated, but the reason is not reported in the registry record. Termination alone does not explain whether the cause was operational, scientific, safety-related, or otherwise. The record does not report whether the planned follow-up was completed or whether the planned analyses were conducted outside the registry entry.

The safety counts indicate zero participants with a serious adverse event among seven at risk and four with other adverse events among seven at risk in the listed MK-2578 group. These counts do not provide comparator safety results, separate dose-level results, event descriptions, or a comparative risk estimate. Deaths are not reported in the registry record.

In general, a clinical trial’s objective, design, and endpoint should be distinguished from its findings. Here, the stated objective describes what investigators aimed to study; it cannot substitute for outcome data. The available record is useful for understanding the intended comparison and the limited safety counts, but it does not support a conclusion about efficacy, comparative benefit, dose response, or comparative safety.

13. Why This Trial Matters Statistically

This trial is statistically notable because the registry identifies a specific continuous primary outcome and a randomized active-comparator design, yet the posted record contains no primary outcome results or analyses. The contrast between a defined question and absent inferential results is important: a trial’s registration details do not by themselves answer its research question.

The small overall enrollment of 7 is also relevant to how readers assess the record. In general, a small study may yield imprecise estimates, and randomization does not ensure balance between groups when enrollment is limited. Here, the group-specific sample sizes and endpoint observations are not reported, so the extent of any imbalance or the precision of a possible estimate cannot be evaluated.

The study includes three listed MK2578 dose groups and an active comparator. Such a design can raise questions about which dose comparisons were planned and how multiple comparisons were handled. The registry record does not report a testing strategy, multiplicity adjustment, or analysis plan. Without these details or any results, dose-specific and comparative interpretations cannot be reconstructed.

The safety information similarly illustrates why denominators and group coverage matter. A count is available for the MK-2578 group, but no comparator safety counts or dose-specific breakdowns are reported. The figures can be described as posted, but they cannot support a comparative safety analysis.

More broadly, the record highlights the difference between a study’s declared aims and its statistical evidence. A meaningful interpretation of treatment effects would require outcome estimates and their uncertainty, along with information on analyzed participants and missing data. Those elements are not reported in the registry record. The study can therefore be characterized statistically by its design and reporting gaps, but not by a quantified treatment effect.

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 primary limitation for interpreting this trial is that no primary endpoint result is reported in the registry record. The record names the Week 4 change-from-baseline hemoglobin outcome and its intended summary as a mean with standard deviation, but gives no group means, standard deviations, contrasts, or uncertainty estimates. No p-values or analysis results are reported.

Enrollment is listed as 7, while group-specific enrollment and participant flow are not reported in the registry record. The record does not state how many participants completed the Week 4 assessment or contributed to each outcome. Without that information, endpoint completeness and the denominators underlying any analysis cannot be assessed.

The study status is terminated, but the reason and timing of termination are not reported in the registry record. The record also does not explain whether the intended follow-up, treatment exposure, or data collection was completed. It is not possible to infer the reason for termination from the status alone.

Although the design is described as randomized and open-label, details of the randomization process, allocation ratio, masking of laboratory personnel, and outcome measurement procedures are not reported in the registry record. The dose and schedule of darbepoetin alfa are also not reported. These omissions limit assessment of how faithfully the planned design was implemented and how the groups might be compared.

The record lists nine outcome measures but does not report a multiplicity approach, missing-data strategy, analysis populations, or statistical model. It also gives no numerical results for secondary outcomes. For safety, the record provides a combined MK-2578 group count but no comparator figures or dose-level breakdown; serious event terms are absent, and deaths are not reported in the registry record. These limitations prevent a complete efficacy or safety interpretation.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of MK2578 in Patients With Chronic Kidney Disease Who Are Not on Dialysis (2578-002) — NCT00968617.
• Registry record last updated 2015-11-02; status last verified 2015-10.
• Results first posted 2011-11-11.
• 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 record describes NCT00968617, a Phase IIb randomized, active comparator-controlled, open-label, parallel-group study of MK2578 in ESA-naive patients with chronic kidney disease who were not on dialysis. The listed groups are MK2578 at 1.0 mcg/kg, 2.0 mcg/kg, and 3.6 mcg/kg, and darbepoetin alfa.

Enrollment was 7. The record lists a start of 2009-11, primary completion of 2010-04, and status as terminated. The primary endpoint was change from baseline in hemoglobin level at Week 4, measured in g/dL and summarized as a mean with standard deviation. The registry lists nine outcome measures and zero analyses.

No primary endpoint results or comparative analyses are reported in the registry record. For the listed MK-2578 safety group, zero of seven participants at risk had a reported serious adverse event, and four of seven had other adverse events. Serious event terms, comparator safety results, and deaths are not reported in the registry record.