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 Methoxy Polyethylene Glycol-epoetin Beta (Mircera) in Participants With Chronic Kidney Disease (PRIMAVERA) (NCT01194154), a randomized phase 2 study. The primary outcome is Yearly Reduction Rate of Estimated Glomerular Filtration Rate (eGFR) Calculated by Modification of Diet in Renal Disease With 4 Variables (MDRD-4).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01194154 |
| Phase | Phase 2 |
| Condition | Kidney Disease, Chronic |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 241 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Hoffmann-La Roche |
| Results posted | Yes |
2. Clinical Question
Population
Participants with chronic kidney disease were eligible for this phase 2 study. The primary endpoint analysis population was the FAS: randomized participants who received at least one dose of study medication and provided a successive eGFR measurement. The registry record does not report further eligibility details in the posted summary.
Intervention
The intervention was methoxy polyethylene glycol-epoetin beta, called Mircera in the record. The planned starting regimen was 30 microgram by subcutaneous injection once monthly. Depending on changes in hemoglobin values, the dose could be adjusted to 50 mcg or 75 mcg once monthly.
Comparator
The comparison group was assigned matching placebo. The study used randomized allocation and a parallel-group design. The registry record identifies the study as single-blind but does not report which people involved in the trial were blinded.
Primary question
The primary question was whether early treatment with Mircera was associated with a different yearly reduction rate in eGFR than placebo over 24 months. The endpoint was calculated from the change in eGFR measurements over time using the MDRD-4 formula. The posted sponsor comparison estimates a treatment effect of 2.21 mL/min/1.73m^2/year, with a 95% confidence interval from -0.35 to 4.78 and p = 0.657. The interval reflects substantial uncertainty about the size and direction of the comparison.
3. Trial Design
PRIMAVERA was a randomized, single-blind, parallel-group, phase 2 proof-of-concept study sponsored by Hoffmann-La Roche. It enrolled 241 participants with chronic kidney disease. The study began on 2010-09-30, and its primary completion date was 2015-03-31; its status is completed. The anticipated time on study treatment was 24 months.
Participants were randomly assigned to Mircera or matching placebo. Mircera was planned as a 30 microgram subcutaneous injection once monthly. Depending on hemoglobin changes, the dose could be adjusted to 50 mcg or 75 mcg once monthly. The registry record does not report further details of the dose-adjustment procedure, including thresholds or timing. It also does not identify which participants or study personnel were blinded.
The primary endpoint was the yearly reduction rate of eGFR calculated using the MDRD-4 formula, with a 24-month timeframe. Posted group estimates are based on 115 participants in the Mircera group and 120 in the placebo group. The primary endpoint population is described as the FAS: randomized participants who received at least one dose and provided a subsequent eGFR measurement. The record does not explain why the numbers in the endpoint groups differ from the overall enrollment.
Other registered outcomes included eGFR calculated with the CKD-EPI formula, calculated creatinine clearance, serum creatinine, urinary albumin creatinine ratio, serum cystatin C, and adverse events and serious adverse events. The record does not report a sample-size justification, a detailed schedule of assessments, or details of how participants were followed after treatment ended.
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: Total 241 participants were enrolled, 2 participants in the Mircera group and 4 participants in the placebo group did not receive medication.
Overall Study
| Stage | Mircera | Placebo |
|---|---|---|
| STARTED | 117 | 124 |
| Full Analysis Set | 115 | 120 |
| Safety Analysis Set | 118 | 117 |
| COMPLETED | 68 | 91 |
| NOT COMPLETED | 49 | 33 |
Reasons for not completing this period:
| Reason | Mircera | Placebo |
|---|---|---|
| Adverse Event | 12 | 7 |
| Lost to Follow-up | 2 | 3 |
| Protocol Violation | 0 | 1 |
| Withdrawal by Subject | 5 | 6 |
| Blood pressure increase | 5 | 3 |
| Hemoglobin decrease | 0 | 1 |
| Hemoglobin increase | 12 | 3 |
| Skipping of CERA treatment at two visits | 3 | 0 |
| Treatment with prohibited medication | 4 | 5 |
| Other | 4 | 0 |
| Did not receive study medication | 2 | 4 |
Analysis population for the primary outcome, as defined in the registry: FAS included all randomized participants who received at least one dose of the study medication and provided any successive eGFR measurement.
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 Full Analysis Set (FAS) included all randomized participants who received at least one dose of the study medication and provided any successive estimated glomerular filtration rate (eGFR) measurement.
| Characteristic | Unit | Mircera | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 115 | 120 | 235 | |
| Age, Continuous | years | 63.37 (SD 12.26) | 62.97 (SD 14.30) | 63.17 (SD 13.31) |
| Sex: Female, Male: Female | Participants | 44 | 44 | 88 |
| Sex: Female, Male: Male | Participants | 71 | 76 | 147 |
6. Primary Endpoint
The registry lists the primary outcome as Yearly Reduction Rate of Estimated Glomerular Filtration Rate (eGFR) Calculated by Modification of Diet in Renal Disease With 4 Variables (MDRD-4), measured over 24 months.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | mL/min/1.73m^2/year |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the yearly reduction rate in estimated glomerular filtration rate, or eGFR, calculated with the MDRD-4 formula. eGFR is an estimate of kidney filtration based on measured and participant characteristics; the registry description identifies age, sex, and serum creatinine as inputs to the MDRD-4 calculation. The endpoint is expressed in mL/min/1.73m^2/year.
Rather than comparing a single eGFR measurement, the endpoint uses a slope estimated from a participant’s eGFR measurements from baseline to Visit 24. The registry defines the yearly reduction rate as -365.25 multiplied by that slope. In general, repeated measurements can describe the pace of change over time, while a single measurement captures only a point in time. The endpoint therefore represents an estimated annual rate of change over the study period, not a direct measurement of kidney function at one visit.
The endpoint is relevant to the study’s stated question about renal disease progression. Its interpretation depends on the measurement schedule and the model used to estimate each participant’s slope. The registry record describes simple linear regression for the individual slopes, but does not report how departures from a linear pattern, missing measurements, or differences in observation time were handled. The posted group estimates and sponsor comparison should consequently be read as estimates of this defined outcome, rather than as direct measures of every aspect of kidney disease progression.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted mean yearly reduction rate was 3.04 mL/min/1.73m^2/year for Mircera, with a 95% confidence interval from 1.2 to 4.87. For placebo, the estimate was 0.82 mL/min/1.73m^2/year, with a 95% confidence interval from -0.96 to 2.61. The sponsor-reported treatment effect was 2.21, with a 95% confidence interval from -0.35 to 4.78 and p = 0.657. The interval is compatible with values on either side of no difference, so the point estimate alone does not determine the direction or size of the underlying effect.
The sponsor used a Wilcoxon (Mann-Whitney) method for the reported comparison. That test compares the distributions of outcomes between groups; it is not simply a test of the difference between the two posted group means. The group estimates are presented as means with confidence intervals, while the sponsor’s comparison is based on a rank-based method. Those summaries answer related but not identical statistical questions, so small differences between a comparison of means and the reported test would not by themselves indicate an error.
A confidence interval describes the uncertainty around an estimate under the assumptions of the method used. A wider interval indicates less precision than a narrower interval. In these results, the sponsor’s interval includes both a negative and a positive treatment-effect value, and the p value is 0.657. Together, these statistics do not establish a clear difference between groups in the primary endpoint. They also do not prove that the groups are identical. The estimates remain uncertain, and the interval includes effects of different directions and magnitudes.
The separate group confidence intervals also overlap. They should not be used as a substitute for the confidence interval for the between-group treatment effect: the relevant uncertainty for the comparison is represented by the sponsor-reported interval. Nor should the group estimates be subtracted to recreate the comparison, because the reported comparison was calculated with a different statistical method.
The registry record does not report an analysis plan specifying a decision threshold, a sample-size justification, or interim analyses. As a result, the posted primary result is best described through its estimate, interval, and reported p value, without claiming that it met a prespecified decision rule. The endpoint population is restricted to participants meeting the FAS definition, and the record does not report whether additional analysis populations were used.
These results concern the defined eGFR slope outcome during the stated timeframe. They do not, by themselves, answer every question about kidney disease progression, treatment effects on other outcomes, or longer-term effects. The registry lists additional outcomes, but the presence of an outcome in the record does not supply its result. Findings for outcomes not reported in the posted results are not reported in the registry record.
9. Statistical Methods Explained
The primary endpoint is a continuous measure: each participant has an estimated yearly reduction rate in eGFR. The posted group summaries are means, which describe the average value within each group. A mean is useful for communicating the center of a continuous outcome, but it does not show the full distribution of individual results. Confidence intervals add information about uncertainty in the estimated group values.
What does the endpoint represent?
The endpoint is based on change over time rather than a single eGFR reading. For each participant, the registry description says that simple linear regression was used to estimate the slope of change from baseline through Visit 24. The slope is then converted to an annual reduction rate by multiplying by -365.25. In general, a slope compresses repeated measurements into one summary of a trend. It can be informative when the scientific question concerns the pace of change, but it may not capture patterns that are not approximately linear. The record does not report whether alternative slope models or sensitivity analyses were used.
The MDRD-4 formula was used for the primary endpoint. The registry description identifies age, sex, and serum creatinine as inputs. A formula-based endpoint is an estimate, not a direct measurement of filtration. The record also lists a secondary eGFR outcome calculated using CKD-EPI, but a different calculation method can produce a different estimate. The primary result should therefore be interpreted as relating specifically to the MDRD-4-based measure.
How should the confidence intervals be read?
A confidence interval gives a range of values that are compatible with the observed data under the statistical method and its assumptions. It expresses uncertainty in an estimate; it is not a range containing a known fraction of individual participant outcomes. The Mircera group estimate was 3.04, with a 95% confidence interval from 1.2 to 4.87. The placebo group estimate was 0.82, with a 95% confidence interval from -0.96 to 2.61. The treatment-effect interval, reported separately, extends from -0.35 to 4.78.
For the comparison, the treatment-effect interval is the central uncertainty summary. Because it ranges from a negative to a positive value, the posted result does not pin down a single direction for the between-group difference. The interval should be considered along with the point estimate, rather than treating the point estimate as definitive. General statistical interpretation also depends on the model and sampling assumptions; details beyond the reported methods are not reported in the registry record.
What does the Wilcoxon comparison test?
The reported comparison used the Wilcoxon (Mann-Whitney) method. In general, this rank-based test assesses whether observations in one group tend to be higher or lower in the distribution than observations in another group. It does not require the same normal-distribution assumption as a basic comparison of means, although it still relies on appropriate study design and valid observations. Its result is not automatically a test of a difference between means. The registry reports the treatment-effect estimate and confidence interval alongside the test, but does not report additional details about how that interval was constructed.
The listed group values are means, while the sponsor’s test is rank-based. A recalculation based on posted summary statistics, if presented, is an unadjusted calculation and may use different assumptions from the sponsor’s analysis. It is not a replacement for the sponsor’s reported test. When the sponsor’s analysis and a recalculation conflict, the sponsor’s own analysis takes precedence; the registry record indicates no such discrepancy for this trial.
Why can over-dispersion matter?
In general, over-dispersion means that observed variation is greater than a model expects. It is especially relevant when outcomes are counts or binary events and a statistical model assumes a particular amount of variation. If extra variation is ignored, uncertainty can be understated. The primary endpoint is continuous and the reported method is rank-based for the treatment comparison, so count-model over-dispersion is not the main issue for interpreting this result. Still, individual eGFR trajectories may vary, and the registry does not report a detailed account of their distribution or diagnostic checks.
What do planning calculations mean?
In general, a sample-size planning illustration asks how many participants per arm might be needed to detect an effect under stated assumptions. Such a calculation is not an observed property of the completed trial and must not be described as observed power. The assumptions listed for planning illustrations include a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects defined as fractions of the observed effect. These are planning assumptions, not reported features of the trial’s original design. The registry record does not report the trial’s own sample-size justification.
Any planning values should be read as conditional illustrations, not as proof that the study had a particular probability of detecting an effect. Their relevance depends on whether the assumed effect, allocation, and analysis match the research question and study design. No planning count is needed to interpret the posted sponsor estimate, confidence interval, or p value.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Wilcoxon (Mann-Whitney) | treatment effect 2.21 | -0.35 to 4.78 | 0.657 |
The sponsor-reported comparison is a treatment effect of 2.21, with a 95% confidence interval from -0.35 to 4.78 and p = 0.657. The reported method was Wilcoxon (Mann-Whitney). The group results are means: 3.04 for Mircera and 0.82 for placebo. A simple subtraction of those means would not reproduce the sponsor’s rank-based comparison, and the sponsor estimate should be read according to the method actually reported.
A recalculated comparison from summary statistics, when available, is an unadjusted calculation and may rely on assumptions different from the sponsor’s method. It can serve as a check, but it is not a substitute for the trial’s reported analysis. For this record, the discrepancy flag is false, so there is no identified disagreement requiring the sponsor analysis to take precedence over a conflicting recalculation. The registry record does not report further details on the construction of the sponsor’s confidence interval.
The confidence interval spans negative and positive values, and the reported p value is 0.657. These results indicate considerable uncertainty in the comparison; they do not establish that the treatment effect is exactly absent or that the groups are equivalent.
11. Multiplicity, Missing Data and Analysis Populations
The registry lists the primary eGFR reduction-rate outcome and six secondary outcomes. The secondary outcomes cover eGFR calculated by CKD-EPI, creatinine clearance, serum creatinine, urinary albumin creatinine ratio, serum cystatin C, and adverse events and serious adverse events. Testing multiple outcomes can increase the chance of finding an apparently unusual result by chance. In general, a prespecified multiplicity strategy may control that risk, but the registry record does not report a multiplicity adjustment or a hierarchy for interpreting the outcomes.
The record reports two analyses. It does not explain whether these were the complete set of analyses planned for the trial or how the analysis choices were made. Interim analyses are not reported in the registry record. A sample-size justification and a detailed statistical analysis plan are also not reported in the registry record, so the planned handling of multiple tests and analysis decisions cannot be assessed from the available information.
The primary endpoint population is the FAS, defined as randomized participants who received at least one dose of study medication and provided any successive eGFR measurement. The record does not give further detail about missing eGFR values, incomplete follow-up, or the method used to handle missing observations in estimating the individual slopes. It also does not report sensitivity analyses assessing the impact of missing data.
The numbers contributing to the posted endpoint estimates are 115 for Mircera and 120 for placebo. These are not the same counts as the enrollment figure or the safety counts. The registry record does not explain the reasons for the different analysis counts, and they should be understood in relation to the stated endpoint population rather than treated as interchangeable denominators.
Without more detail, it is not possible to determine whether the analysis population and missing-data procedures were prespecified, or how robust the estimates are to alternative assumptions. These gaps do not invalidate the reported results, but they limit how fully the analysis can be evaluated.
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 |
|---|---|---|---|
| Mircera | 42 | 118 | 35.6% |
| Placebo | 48 | 117 | 41.0% |
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 |
|---|---|
| Mircera | 95 of 118 |
| Placebo | 99 of 117 |
Most frequent serious adverse event terms
| Event term | Organ system | Mircera | Placebo |
|---|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 2 of 118 | 3 of 117 |
| Dyspnoea | Respiratory, thoracic and mediastinal disorders | 4 of 118 | 0 of 117 |
| Hypoglycaemia | Metabolism and nutrition disorders | 2 of 118 | 1 of 117 |
| Peripheral arterial occlusive disease | Vascular disorders | 0 of 118 | 3 of 117 |
| Renal failure acute | Renal and urinary disorders | 1 of 118 | 2 of 117 |
| Haemoglobin decreased | Investigations | 2 of 118 | 1 of 117 |
| Bronchopneumonia | Infections and infestations | 1 of 118 | 1 of 117 |
| Erysipelas | Infections and infestations | 1 of 118 | 1 of 117 |
| Gastroenteritis | Infections and infestations | 2 of 118 | 0 of 117 |
| Infection | Infections and infestations | 1 of 118 | 1 of 117 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Mircera | Placebo |
|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 29 of 118 | 24 of 117 |
| Hypertension | Vascular disorders | 11 of 118 | 14 of 117 |
| Diarrhoea | Gastrointestinal disorders | 11 of 118 | 13 of 117 |
| Cough | Respiratory, thoracic and mediastinal disorders | 13 of 118 | 10 of 117 |
| Oedema peripheral | General disorders | 11 of 118 | 10 of 117 |
| Urinary tract infection | Infections and infestations | 12 of 118 | 7 of 117 |
| Influenza | Infections and infestations | 9 of 118 | 9 of 117 |
| Bronchitis | Infections and infestations | 0 of 118 | 9 of 117 |
| Back pain | Musculoskeletal and connective tissue disorders | 0 of 118 | 8 of 117 |
| Nausea | Gastrointestinal disorders | 0 of 118 | 8 of 117 |
Serious events with the highest arm-level rate: dyspnoea (3.4%), diarrhoea (2.6%), peripheral arterial occlusive disease (2.6%), atrial flutter (1.7%), faecaloma (1.7%).
The posted safety figures report serious adverse events for 42 of 118 participants in the Mircera group and 48 of 117 participants in the placebo group. The registry also reports other adverse events for 95 of 118 participants in the Mircera group and 99 of 117 participants in the placebo group. These are counts of participants with events, not counts of every event occurrence. The record does not define the distinction between the serious and other event categories in the posted summary.
The most frequently listed serious-event terms include dyspnoea at 3.4%, diarrhoea at 2.6%, peripheral arterial occlusive disease at 2.6%, atrial flutter at 1.7%, faecaloma at 1.7%, and back pain at 1.7%. These terms describe events reported in the record; they do not by themselves establish that an event was caused by study treatment. The registry record does not report an attribution analysis or further detail about timing, duration, or severity for these terms.
Deaths are not reported in the registry record. The available counts should not be treated as a complete safety profile or as proof of a difference between groups. They also should not be compared without considering the separate group denominators and the limited detail on event definitions and follow-up.
13. What the Result Does, and Does Not, Mean
The primary result is an estimate of the difference between groups in a particular measure: the yearly reduction rate in MDRD-4 eGFR over 24 months. The sponsor reported a treatment effect of 2.21, with a 95% confidence interval from -0.35 to 4.78 and p = 0.657. The interval includes values in both directions, so the data do not identify a precise direction or magnitude for the comparison. The point estimate is one component of the result, not a complete account of its uncertainty.
The result does not establish equivalence between Mircera and placebo. Demonstrating equivalence or non-inferiority generally requires a prespecified margin and an analysis designed for that question; such a margin and plan are not reported in the registry record. Likewise, the result does not prove that there is no treatment effect. An uncertain estimate can be compatible with more than one possibility.
The endpoint is an estimated slope based on repeated eGFR measurements and the MDRD-4 formula. It is not a direct measurement of every aspect of kidney function, and it does not capture all dimensions of chronic kidney disease. Other registered outcomes may address related aspects, but results for outcomes not included in the posted results are not reported in the registry record.
The study is described as a proof-of-concept trial. That description indicates the stated study purpose, but it does not tell the reader what sample-size justification, decision rule, or statistical analysis plan was used. Those details are not reported in the registry record. The result should therefore be interpreted as the reported estimate and uncertainty for this trial, without extending it to other populations, treatment schedules, or longer periods than those described.
Safety counts provide a separate descriptive view. They report participants with serious and other adverse events in each group, but the posted summary does not provide enough detail to determine causality or fully characterize the events. Taken together, efficacy and safety findings should be read as trial-specific observations, not as a complete account of treatment effects.
14. Why This Trial Matters Statistically
This trial illustrates why a treatment-effect estimate should be read alongside its uncertainty. The sponsor’s point estimate is positive, but its 95% confidence interval ranges from -0.35 to 4.78. The confidence interval is essential to understanding how imprecisely the comparison is estimated; the point estimate alone would give an incomplete impression.
It also illustrates that a group mean comparison and a rank-based test are not interchangeable. The posted group summaries are means, whereas the reported Wilcoxon (Mann-Whitney) method compares the distributions using ranks. Researchers and readers need to identify which statistical question a method addresses before comparing numerical results or attempting a recalculation.
The endpoint itself depends on a sequence of measurements and a slope model. A summary rate can make a longitudinal question easier to interpret, but that summary depends on the calculation method, observation pattern, and missing-data approach. The record describes the basic slope calculation and the FAS definition, while leaving important implementation details unreported.
Finally, the study record separates the primary efficacy outcome from several secondary outcomes and safety summaries. That distinction matters because multiple outcomes can raise questions about multiplicity, and descriptive safety counts do not establish causation. The registry record does not report a multiplicity strategy or detailed safety attribution. These features make transparent reporting of analysis choices and uncertainty especially important when interpreting a proof-of-concept study.
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 registry record leaves several trial-specific details unreported. It does not identify who was blinded, describe the allocation procedure beyond randomized assignment, or give a detailed account of the dose-adjustment thresholds and timing. Those omissions limit assessment of how the planned intervention and masking were implemented.
The primary endpoint relies on individual eGFR slopes from baseline to Visit 24. The record describes simple linear regression but does not report the number or timing of measurements used for each participant, the handling of incomplete measurement sequences, or checks of the linearity assumption. It also does not describe sensitivity analyses for the slope estimates or missing data.
The endpoint estimates use 115 participants in the Mircera group and 120 in the placebo group, while the overall enrollment is 241. Safety figures use separate denominators of 118 and 117. The record does not explain the reasons for these different counts, so the analysis populations and denominator differences cannot be fully evaluated from the posted summary alone.
The sponsor’s comparison uses a Wilcoxon (Mann-Whitney) method, while the group summaries are means. The registry record does not provide further detail about the treatment-effect estimator or construction of its confidence interval. It also does not report a detailed analysis plan, a sample-size justification, interim analyses, or a multiplicity strategy for the primary and secondary outcomes.
The safety summary gives participant counts and selected serious-event terms but does not report deaths, event timing, treatment attribution, or detailed event-level information. These limitations constrain interpretation of both efficacy and safety. They do not negate the posted results, but they mean the record does not support a more complete reconstruction of the trial’s analysis or conduct.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: A Study of Methoxy Polyethylene Glycol-epoetin Beta (Mircera) in Participants With Chronic Kidney Disease (PRIMAVERA) — NCT01194154.
- Registry record last updated 2017-05-10; status last verified 2017-04.
- Results first posted 2016-06-14.
- 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
PRIMAVERA was a completed, randomized, single-blind, parallel-group, phase 2 proof-of-concept study sponsored by Hoffmann-La Roche. It enrolled 241 participants with chronic kidney disease and compared monthly Mircera with matching placebo. The anticipated treatment period was 24 months.
The primary endpoint was the yearly reduction rate of MDRD-4 eGFR. The posted means were 3.04 for Mircera and 0.82 for placebo. The sponsor-reported treatment effect was 2.21, with a 95% confidence interval from -0.35 to 4.78 and p = 0.657. The interval indicates uncertainty about the direction and size of the comparison.
Serious adverse events were reported for 42 of 118 participants assigned to Mircera and 48 of 117 assigned to placebo. The registry record does not report deaths. Important details about missing data, multiplicity, sample-size justification, and the full statistical analysis plan are not reported in the registry record.