This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Study of Mircera in Anemic Patients With Chronic Kidney Disease Not Yet on Dialysis. (NCT00048048), a randomized phase 2 study. The primary outcome is The Change in Hemoglobin Over Time Between Baseline and End of Initial Treatment Based on Individual Regression Slopes.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00048048 |
| Phase | Phase 2 |
| Condition | Anemia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 65 |
| Arms in the primary outcome | 9 |
| Lead sponsor | Hoffmann-La Roche |
| Results posted | Yes |
2. Clinical Question
Population
Anemic patients with chronic kidney disease who were not yet on dialysis or other renal replacement therapy. The registry defines the primary analysis population as all randomized participants, with the maximum number of participants with available data reported.
Intervention
Subcutaneous methoxy polyethylene glycol-epoetin beta, identified as RO0503821 or Mircera, given across nine dose-and-frequency cohorts. The regimens used weekly, every-two-week, or every-three-week dosing, with different starting doses.
Comparator
The comparison was among active Mircera dosing regimens. The registry record does not describe a placebo or untreated comparator. The reported primary analyses also group cohorts by dosing frequency rather than presenting a single treatment-versus-control contrast.
Primary question
How did hemoglobin change from baseline through the end of initial treatment under the different regimens, as summarized using each participant’s regression slope and the cohort summaries? The registry reports group-level analyses as well as cohort-level estimates.
The clinical question is therefore about dose and schedule patterns within an active-treatment study, not about a comparison of Mircera with no treatment or with another drug. The registry lists hemoglobin change over time as the primary efficacy measure. The endpoint includes observations through end of initial treatment, with the stopping point defined using dose changes or blood transfusions; for participants without dose adjustments, that endpoint coincided with Week 19.
The design can describe the observed hemoglobin patterns across the tested regimens, but the record does not report a single randomized contrast that isolates the effect of one dose or schedule against a common control. The trial’s open-label design and multiple cohorts also mean that interpretation should remain tied to the estimates and analyses actually posted. The registry does not report a primary hypothesis test or a multiplicity-adjusted comparison among all nine cohorts.
3. Trial Design
This was a randomized, open-label, parallel, multicentre phase 2 trial of methoxy polyethylene glycol-epoetin beta in patients with chronic renal anemia who were not on renal replacement therapy. The registry lists enrollment of 65 participants and describes nine cohorts receiving different subcutaneous doses and schedules. Every cohort received the study drug; the record does not identify a placebo or non-Mircera group.
The regimens were organized around weekly, every-two-week, and every-three-week dosing, with three starting-dose levels within each schedule. The initial treatment description refers to dosing over periods of up to six weeks, followed by a one-week follow-up. The primary endpoint timeframe extends from baseline to end of initial treatment at Week 19. The brief summary describes anticipated time on study treatment as 3-12 months, and the listed heart-rate outcome has a timeframe up to Week 125.
Random allocation can help balance participant characteristics across assigned groups, but the registry does not report the allocation sequence method, concealment procedures, or a detailed randomization ratio. Masking was none, so treatment assignment was open-label. The record does not report whether outcome assessors were masked.
The primary analysis population is defined as all randomized participants, while the endpoint description says that the maximum number with available data was reported. Cohort-level hemoglobin estimates are presented for the nine regimens; additional reported analyses combine three cohorts at a time into three least-squares mean summaries. The record does not explain the model used for those least-squares means or provide a detailed statistical analysis plan.
The study is marked completed. Its registration describes multiple-dose evaluation of efficacy and safety, rather than a single confirmatory comparison. The planned sample-size justification, target allocation by cohort, interim analyses, and any prespecified stopping rules 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.
Only the first 6 of 12 groups are shown.
Core Treatment
| Stage | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| STARTED | 6 | 6 | 10 | 6 | 6 | 9 |
| COMPLETED | 6 | 6 | 9 | 6 | 6 | 9 |
| NOT COMPLETED | 0 | 0 | 1 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| Withdrawal by Subject | 0 | 0 | 1 | 0 | 0 | 0 |
| Adverse Event | 0 | 0 | 0 | 0 | 0 | 0 |
Extension Year 1
| Stage | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| Early withdrawals | 0 | 0 | 0 | 0 | 0 | 0 |
Extension Year 2
| Stage | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 0 | 0 | 0 |
| COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 | 0 | 0 | 0 |
Reasons for not completing this period:
| Reason | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821, 0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821, 0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|
| Early withdrawals | 0 | 0 | 0 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The Intent-to-Treat (ITT) population was defined as all randomized participants. Maximum number of participants with available data was reported.
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: The safety population was considered for analysis which included all participants who received at least one dose of study drug.
Only the first 6 of 10 groups are shown.
| Characteristic | Unit | Cohort 1 (RO0503821, 0.15 mcg/kg 1x/Week) | Cohort 2 (RO0503821,0.3 mcg/kg 1x/Week) | Cohort 3 (RO0503821,0.6 mcg/kg 1x/Week) | Cohort 4 (RO0503821, 0.3 mcg/kg 1x/2 Week) | Cohort 5 (RO0503821, 0.6 mcg/kg 1x/2Week) | Cohort 6 (RO0503821, 1.2 mcg/kg 1x/2 Week) |
|---|---|---|---|---|---|---|---|
| Participants analysed | 6 | 6 | 10 | 6 | 6 | 9 | |
| Age, Continuous | Years | 58.2 (SD 21.66) | 70.0 (SD 13.75) | 58.0 (SD 16.55) | 60.3 (SD 16.80) | 62.7 (SD 21.29) | 62.3 (SD 12.63) |
| Sex: Female, Male: Female | Participants | 4 | 4 | 6 | 4 | 5 | 6 |
| Sex: Female, Male: Male | Participants | 2 | 2 | 4 | 2 | 1 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as The Change in Hemoglobin Over Time Between Baseline and End of Initial Treatment Based on Individual Regression Slopes, measured over From Baseline (Day -28 to Day 1) to EOIT (Week 19).
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | gram/deciliter (g/dL) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint concerns change in blood hemoglobin over time from baseline through end of initial treatment. Baseline is defined as the mean hemoglobin from the screening assessment and Weeks -2 and -1 of the run-in period. For each participant, the primary efficacy parameter was the change over time based on a regression slope. Values through end of initial treatment were included, with that endpoint defined as the last observed value before a dose change or blood transfusion. For participants without dose adjustments, the end-of-initial-treatment value was the Week 19 value.
Hemoglobin is a continuous laboratory measure, so tracking its trajectory can provide information about the direction and pattern of change during treatment, rather than only recording a single final measurement. A regression slope condenses repeated measurements for each participant into a summary of change over time. The registry reports the cohort summaries as medians, with interquartile range identified as the dispersion measure. Numerical interquartile ranges are not reported in the registry record.
The registry also reports three least-squares mean analyses that group the cohorts by dosing schedule. These estimates are distinct from the cohort-level medians: they are model-based summaries, but the model specification is not reported in the registry record. Neither the endpoint description nor the posted analyses establish that these grouped summaries are direct pairwise comparisons among all nine regimens. The results should therefore be read as descriptive and model-based summaries of the recorded hemoglobin trajectories, with their precision and analytic scope kept in view.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The nine cohort-level median estimates range from 0.17 to 2.17 g/dL. The lowest posted estimate is for Cohort 4, at 0.17 g/dL, with reported interval bounds from -0.47 to 0.52. The highest is for Cohort 6, at 2.17 g/dL, with bounds from 1.38 to 2.61. Other cohort medians and their reported bounds also vary across regimens. The registry does not specify the confidence level or construction method for these cohort-level bounds, so they should not be assigned a confidence-interval interpretation beyond what the record states.
The grouped analyses report least-squares means of 0.979 for the weekly cohorts, 0.851 for the every-two-week cohorts, and 0.932 for the every-three-week cohorts. Each is accompanied by a 95% confidence interval: 0.534 to 1.425, 0.395 to 1.307, and 0.488 to 1.377, respectively. These estimates are presented as separate summaries, not as reported tests of differences among the three schedules. No p-values are reported for these primary analyses, and the registry does not report a formal pairwise contrast among schedules.
A confidence interval describes a range of values compatible with the analysis under its statistical assumptions; it does not show the probability that a particular treatment effect is true. The width of an interval conveys precision: wider intervals indicate less precision than narrower ones. Here, the cohort sizes are small, and the interval bounds vary across regimens. That makes it important to avoid treating the ordering of point estimates as a reliable ranking of regimens.
The endpoint itself is a change-over-time measure based on individual regression slopes, but the registry does not provide the participant-level data, model details, or all distribution summaries needed to reconstruct the analysis. It also does not report a common control arm. Thus, the estimates characterize observed hemoglobin patterns during the assigned Mircera regimens; they do not, on their own, establish how those patterns compare with no study drug or with another treatment.
The posted results show variation between cohort estimates and uncertainty around those estimates. The record does not report a statistical test establishing that one dose or schedule differs from another. Nor should estimates from a small number of participants be interpreted as definitive evidence about the relative performance of the regimens. The primary results are best understood as exploratory summaries in a phase 2, multiple-dose trial.
9. Statistical Methods Explained
The primary endpoint uses a regression slope for each participant to summarize hemoglobin change over time. In general, regression uses observed data to describe a relationship between a response and one or more explanatory variables; in a repeated-measure setting, a slope can summarize the direction and rate of change over the observed period. The registry states that individual slopes were used, but the exact regression specification, handling of irregular measurement times, and assumptions are not reported in the registry record.
The cohort-level primary summaries are medians. A median is the middle value when observations are ordered and is less sensitive to extreme values than a mean. The registry identifies interquartile range as the dispersion measure, which in general describes the middle half of a distribution. However, numerical interquartile ranges are not reported in the registry record, and the cohort estimates are accompanied by bounds whose method and confidence level are not specified there. It would be inappropriate to assume those bounds are a particular type of interval without that information.
The record separately reports least-squares means for three sets of cohorts. In general, a least-squares mean is an adjusted mean estimated from a statistical model. The three reported values are 0.979, 0.851, and 0.932, each with a 95% confidence interval. The model formula, covariates, weighting, and treatment of missing observations are not reported in the registry record. These group summaries should not be mistaken for the cohort medians: they are different summary measures, and the registry does not give enough detail to explain how they relate analytically.
A confidence interval gives a range of estimates that would be compatible with the data and model under repeated use of the same procedure, assuming the method’s conditions hold. It reflects uncertainty in an estimate, not the range of individual participant outcomes and not the probability that the effect lies in the interval. The 95% confidence level is explicitly given for the grouped least-squares mean results. The confidence level for the cohort-level interval bounds is not reported in the registry record.
Randomization is a design method intended to reduce systematic differences in baseline characteristics between assigned groups. Open-label treatment means participants and study personnel were not masked to assignment according to the registry’s masking classification. In general, lack of masking can affect behavior, reporting, or decisions about care and outcome measurement. The record does not report further protections or assessment procedures that would clarify the potential influence on these outcomes.
The study has nine active-treatment cohorts, and the three primary least-squares mean analyses pool cohorts according to dosing frequency. A pooled summary can help describe a broader set of regimens, but combining cohorts can obscure differences among their dose levels. The record does not report tests comparing all individual cohorts, nor a prespecified plan for comparisons among the schedules. Without those details, the separate estimates should not be treated as a ranking or as proof of a dose-response pattern.
Several secondary comparisons are recalculated as unadjusted mean differences from posted summary statistics. In general, a mean difference subtracts one group mean from another, while its confidence interval reflects uncertainty under the calculation’s assumptions. An unadjusted p-value does not account for the number of endpoints, time points, or comparisons examined. The displayed secondary results therefore require cautious interpretation, especially when many outcomes or comparisons are considered. The registry does not report a multiplicity adjustment for the secondary analyses.
Over-dispersion is a general issue when observed variability is greater than a statistical model expects. If a model assumes less variability than the data contain, standard errors may be too small and intervals may be too narrow. The record does not identify a count-data model for the primary endpoint, and no over-dispersion assessment is reported in the registry record. Thus, over-dispersion is a general statistical consideration rather than a documented feature of this analysis.
The sample-size illustrations use observed secondary effects and assumptions for prospective planning. In general, such calculations ask how many participants per arm might be needed to detect an effect under specified conditions. They are planning illustrations, not observed power and not evidence that the trial had a particular probability of detecting its primary endpoint. The registry’s own design assumptions and sample-size justification are not reported in the registry record.
Finally, the analysis population is defined as all randomized participants, but the endpoint description specifies values available through end of initial treatment and says the maximum number with available data was reported. General approaches to missing data include complete-case analysis, imputation, and model-based methods, each relying on different assumptions. Which method, if any, was used is not reported in the registry record. The amount and pattern of missing primary endpoint data are also not reported there.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| not stated | Least square mean 0.979 | 0.534 to 1.425 | not reported |
| not stated | Least square mean 0.851 | 0.395 to 1.307 | not reported |
| not stated | Least square mean 0.932 | 0.488 to 1.377 | not reported |
The registry reports the primary hemoglobin results as cohort-level medians and as three grouped least-squares means with 95% confidence intervals. Those are the sponsor’s posted analyses in the registry record; p-values for the primary grouped results are not reported. The available information does not include a recalculated primary comparison that can be set against the sponsor’s analysis, and no discrepancy is flagged for the primary results.
The registry also includes a secondary heart-rate comparison recalculated from posted summary statistics. Such recalculations are unadjusted and are not a substitute for a prespecified sponsor analysis. The sponsor’s own reported-analysis list for that secondary endpoint is empty in the registry record, so a corresponding sponsor estimate or test is not reported there. The recalculated result should consequently be read as an analytical illustration based on posted group summaries, not as the trial’s primary inferential conclusion.
Where a sponsor analysis is available, its specification and status matter: a model-based analysis may account for design or data features that a simple summary-statistic calculation cannot. The registry does not provide enough detail to assess all such features for the primary endpoint. The most defensible reading is therefore to describe the sponsor’s posted primary estimates as reported, distinguish them from secondary recalculations, and avoid treating an unadjusted recalculation as a replacement for an analysis specified by the trial investigators.
11. Multiplicity, Missing Data and Analysis Populations
The trial evaluates one primary endpoint alongside several secondary outcomes, with repeated measurements over time and nine active-treatment cohorts. This creates multiple possible comparisons. In general, multiplicity matters because the chance of encountering a nominally unusual result can increase when many tests are performed. A prespecified hierarchy or adjustment can help control that issue, but the registry does not report a multiplicity adjustment or a detailed testing hierarchy.
The primary grouped analyses are presented as least-squares means with 95% confidence intervals, but no p-values or formal between-group tests are reported. The record also does not state whether those analyses were prespecified, whether additional contrasts were considered, or how any such contrasts were handled. The registry record does not report interim analyses or an interim-testing plan.
The primary population is described as all randomized participants, and the endpoint description says the maximum number of participants with available data was reported. The endpoint includes values through end of initial treatment, which is the last observed value before a dose change or blood transfusion. The record does not report the number of missing primary measurements, the reasons for missingness, or the method used to handle missing values. It also does not report imputation or sensitivity analyses for missing data.
In general, missing-data methods rely on assumptions about why values are unavailable and how unobserved values relate to observed information. Without the missingness pattern and analysis method, it is not possible to assess how sensitive the estimates may be to those assumptions. The statement that the maximum number with available data was reported does not by itself establish that all randomized participants contributed to every analysis.
The planned sample-size justification is not reported in the registry record. The record also does not describe a statistical analysis plan in enough detail to determine how multiplicity, missing observations, or all cohort comparisons were handled. These gaps limit reconstruction of the inferential framework and reinforce the need to treat the findings as reported summaries rather than as a complete account of confirmatory testing.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| RO0503821 (1x/Week) | 11 | 22 | 50.0% |
| RO0503821 (1x/2Week) | 9 | 21 | 42.9% |
| RO0503821 (1x/3week) | 12 | 22 | 54.5% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| RO0503821 (1x/Week) | 16 of 22 |
| RO0503821 (1x/2Week) | 18 of 21 |
| RO0503821 (1x/3week) | 22 of 22 |
Most frequent serious adverse event terms
| Event term | Organ system | RO0503821 (1x/Week) | RO0503821 (1x/2Week) | RO0503821 (1x/3week) |
|---|---|---|---|---|
| Renal failure acute | Renal and urinary disorders | 1 of 22 | 1 of 21 | 2 of 22 |
| Renal Cyst Ruptured | Renal and urinary disorders | 2 of 22 | 0 of 21 | 0 of 22 |
| Cardiac Failure Congestive | Cardiac disorders | 2 of 22 | 0 of 21 | 0 of 22 |
| Cellulitis | Infections and infestations | 0 of 22 | 1 of 21 | 1 of 22 |
| Urinary Tract Infection | Infections and infestations | 0 of 22 | 1 of 21 | 1 of 22 |
| Gastrointestinal Haemorrhage | Gastrointestinal disorders | 0 of 22 | 0 of 21 | 2 of 22 |
| Haemorrhage urinary tract | Renal and urinary disorders | 1 of 22 | 0 of 21 | 0 of 22 |
| Hydronephrosis | Renal and urinary disorders | 1 of 22 | 0 of 21 | 0 of 22 |
| Nephrolithiasis | Renal and urinary disorders | 1 of 22 | 0 of 21 | 0 of 22 |
| Acute coronary syndrome | Cardiac disorders | 0 of 22 | 1 of 21 | 0 of 22 |
Most frequent non-serious adverse event terms
| Event term | Organ system | RO0503821 (1x/Week) | RO0503821 (1x/2Week) | RO0503821 (1x/3week) |
|---|---|---|---|---|
| Hypertension | Vascular disorders | 6 of 22 | 2 of 21 | 5 of 22 |
| Urinary Tract Infection | Infections and infestations | 3 of 22 | 4 of 21 | 5 of 22 |
| Renal Failure Chronic | Renal and urinary disorders | 3 of 22 | 4 of 21 | 3 of 22 |
| Oedema Peripheral | General disorders | 1 of 22 | 5 of 21 | 3 of 22 |
| Nasopharyngitis | Infections and infestations | 1 of 22 | 4 of 21 | 2 of 22 |
| Gout | Metabolism and nutrition disorders | 2 of 22 | 3 of 21 | 2 of 22 |
| Insomnia | Psychiatric disorders | 0 of 22 | 6 of 21 | 1 of 22 |
| Influenza Like Illness | General disorders | 2 of 22 | 1 of 21 | 3 of 22 |
| Headache | Nervous system disorders | 0 of 22 | 3 of 21 | 3 of 22 |
| Diarrhoea | Gastrointestinal disorders | 1 of 22 | 2 of 21 | 2 of 22 |
Serious events with the highest arm-level rate: renal failure acute (9.1%), renal cyst ruptured (9.1%), cardiac failure congestive (9.1%), gastrointestinal haemorrhage (9.1%), acute coronary syndrome (4.8%).
The safety results group participants by dosing frequency. For serious adverse events, the registry reports 11 affected participants among 22 at risk in the weekly group, 9 among 21 in the every-two-week group, and 12 among 22 in the every-three-week group. For any adverse event, the corresponding reported counts are 16 among 22, 18 among 21, and 22 among 22. These are participant counts within each safety group; they are not event counts and should not be combined across groups without a prespecified analysis.
The registry lists serious adverse-event terms that include acute renal failure, ruptured renal cyst, congestive cardiac failure, gastrointestinal hemorrhage, acute coronary syndrome, and gout, with percentages recorded for those terms. These terms provide a description of events recorded, but the registry information does not establish that the study drug caused them. The record does not report deaths.
Safety comparisons require care because the groups are small, the study is open-label, and no statistical comparison of safety groups is reported. Counts alone do not account for differences in exposure duration or other participant characteristics. The posted figures describe events recorded during the study; they do not by themselves establish comparative risks or causation.
13. What the Result Does, and Does Not, Mean
The primary results describe hemoglobin changes observed during initial treatment with different Mircera dose-and-frequency regimens. Cohort-level estimates vary, and the grouped least-squares mean summaries include confidence intervals. These statistics communicate both the observed pattern and its uncertainty. The record does not report a formal test showing that one schedule or dose is superior to another.
Because all listed cohorts received active treatment, the results do not estimate a contrast between Mircera and no treatment. They also do not establish comparative effects against another therapy. The variation among cohort summaries should not be read as a definitive dose-response relationship: cohort sizes are limited, reported intervals vary, and the record does not provide a model or formal analysis for comparing every dose level.
The endpoint summarizes hemoglobin change over time through a defined treatment endpoint, rather than reporting only a single fixed-time value for every participant. That approach incorporates repeated observations, but the record does not give enough methodological detail to reproduce the regression-slope calculation or assess every assumption. The bounds reported for cohort estimates also lack a stated confidence level.
Secondary outcomes and safety counts add descriptive context, but they do not convert the primary findings into confirmatory evidence. The secondary comparisons are unadjusted, and the registry does not report multiplicity control. The safety summaries describe affected participants and recorded event terms without establishing causation.
Overall, the registry record supports a cautious description of observed results across the tested regimens. It does not, by itself, establish that a particular regimen is better, quantify a treatment effect relative to a non-Mircera comparator, or resolve the limitations associated with missing analytic detail. These are statistical interpretations of the posted data, not medical advice.
14. Why This Trial Matters Statistically
Statistically, this trial is useful as an example of how a phase 2 multiple-dose study can generate several kinds of summaries from one endpoint. The primary analysis begins with participant-level regression slopes, then presents cohort medians as well as grouped least-squares means. Those summaries answer related but not identical questions. Keeping the estimands and summary measures distinct is essential when interpreting a multi-cohort trial.
The design also illustrates the difference between an active-regimen study and a treatment-versus-control trial. Randomization is listed, but the cohorts all receive Mircera and the posted primary analyses are grouped by dosing schedule. The summaries can describe the measured hemoglobin patterns within those regimens; they do not create a common untreated counterfactual or automatically provide pairwise tests.
Small cohort sizes make interval estimates and the limits of precision especially important. Reporting point estimates alone could make differences between regimens appear more certain than the data support. The registry’s grouped confidence intervals offer some information about uncertainty, while the incomplete specification of the cohort-level bounds and model details limits deeper assessment.
The record also highlights why analysis populations, missing data, and multiplicity matter. The primary population is defined as all randomized participants, but the endpoint relies on available observations through a treatment-defined endpoint. The record does not explain missing-data methods or the approach to multiple comparisons. In multi-outcome studies, these details shape how much confidence to place in patterns that emerge from individual results.
Finally, the trial distinguishes sponsor-reported primary estimates from unadjusted secondary recalculations. A recalculation from summary statistics can be useful for illustration, but it cannot replace a full analysis plan or account for details absent from aggregate data. This distinction is central to responsible statistical reading of registry results.
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 study has nine cohorts but enrollment of 65 participants, so the individual regimen groups are small. Estimates from small groups can be imprecise, and the cohort summaries should not be used to create a confident ranking of doses or schedules. The registry does not report a sample-size justification that would show what precision or detectable effect the trial was designed to achieve.
All cohorts received active Mircera, and the registry does not identify a placebo or untreated comparator. The primary results therefore describe outcomes across active regimens rather than estimating an effect relative to no study drug. The open-label design is another limitation: masking was none, and the registry does not describe whether outcome assessment was masked.
The primary endpoint is based on individual regression slopes, but the model specification and handling of repeated measurements are not reported. The cohort-level summaries are medians with interquartile range identified as dispersion, yet numerical interquartile ranges are not reported. The confidence level and method for the cohort-level interval bounds are also not reported in the registry record. The grouped least-squares mean model is not specified.
The endpoint permits observations up to the last value before a dose change or blood transfusion. The record does not report how many participants had such changes, how many measurements were missing, or how missing values were handled. The relationship between the primary analysis population and the number contributing to each estimate is not fully described.
Multiplicity procedures, interim analyses, detailed prespecified contrasts, and the statistical analysis plan are not reported in the registry record. Numerical results for most listed secondary measures are also not reported there. These limitations restrict the ability to reproduce the analyses and assess the robustness of the broader findings.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: A Study of Mircera in Anemic Patients With Chronic Kidney Disease Not Yet on Dialysis. — NCT00048048.
- Registry record last updated 2018-01-02; status last verified 2017-05.
- Results first posted 2018-01-02.
- 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.
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19. Record Summary
NCT00048048 is a completed randomized, open-label, parallel phase 2 study of subcutaneous Mircera in anemic patients with chronic kidney disease not yet on dialysis. The registry lists enrollment of 65 and nine active-treatment cohorts spanning weekly, every-two-week, and every-three-week schedules.
The primary endpoint summarizes hemoglobin change over time from baseline through end of initial treatment using individual regression slopes. The record posts cohort-level medians and three grouped least-squares mean estimates with 95% confidence intervals. It does not report p-values for the primary analyses or a formal comparison among the regimens.
Secondary outcomes include hematocrit, reticulocyte count, adverse events, laboratory abnormalities, heart rate, and blood pressure. Safety results include serious adverse events and any adverse events grouped by dosing frequency. Details on the statistical analysis plan, sample-size justification, multiplicity, and missing-data methods are not reported in the registry record.