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 Efficacy and Safety of Nefecon in Patients With Primary IgA (Immunoglobulin A) Nephropathy (NCT03643965), a randomized phase 3 study. The primary outcome is Part A: Ratio of Urine Protein to Creatinine Ratio (UPCR) at 9 Months Compared to Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03643965 |
| Phase | Phase 3 |
| Condition | Primary IgA Nephropathy |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 365 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Calliditas Therapeutics AB |
| Results posted | Yes |
2. Clinical Question
Population
Patients with primary IgA nephropathy considered at risk of progressing to end-stage renal disease, despite maximum tolerated treatment with renin-angiotensin system blockade using ACE inhibitors or angiotensin II type I receptor blockers.
Intervention
Nefecon 16 mg once daily by mouth for 9 months.
Comparator
Placebo oral capsule once daily by mouth for 9 months.
Primary question
At 9 months, how did the ratio of urine protein to creatinine ratio (UPCR) relative to baseline compare between the Nefecon and placebo groups? UPCR was based on 24-hour urine collections.
The primary question concerns a change in measured urinary protein, expressed as a ratio to baseline, rather than a direct comparison of kidney failure events. The registry describes the broader study aim as evaluating efficacy, safety, and tolerability in patients whose disease may progress despite background RAS blockade. Part A’s primary endpoint was assessed at 9 months. Part B included outcomes followed over 2 years, including time to a 30% reduction in estimated glomerular filtration rate (eGFR) and time to receiving rescue medication. Those later outcomes address different aspects of the clinical course and should not be treated as interchangeable with the primary UPCR measure.
3. Trial Design
This was a completed Phase 3, randomized, quadruple-masked, parallel-group study. The registry lists an enrollment of 365. Patients were assigned to Nefecon or placebo; the listed regimens were taken orally once daily for 9 months. The registry describes the study as double-blind in its official title and records quadruple masking in its design information.
The trial had two parts. Part A’s primary endpoint compared UPCR at 9 months with baseline, using 24-hour urine collections. The primary analysis population is described as the full analysis set for the global study, Part A. The reported group estimates include 97 participants for Nefecon and 102 for placebo. Part B outcomes were followed over 2 years, and the posted denominators for the time-to-event and other detailed secondary results are 182 participants in each group. These are outcome-specific analysis counts; the registry record does not explain the relationship between each analysis population and overall enrollment.
The population was patients with primary IgA nephropathy at risk of progression despite maximum tolerated RAS blockade. The control was a placebo oral capsule. The registry record identifies Calliditas Therapeutics AB as sponsor and gives the status as completed. Further details about the randomization procedure, allocation concealment, masking procedures, adherence, and treatment discontinuation 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.
Part A
| Stage | Nefecon | Placebo Oral Capsule |
|---|---|---|
| STARTED | 182 | 182 |
| COMPLETED | 175 | 174 |
| NOT COMPLETED | 7 | 8 |
Part B
| Stage | Nefecon | Placebo Oral Capsule |
|---|---|---|
| STARTED | 175 | 174 |
| COMPLETED | 161 | 165 |
| NOT COMPLETED | 14 | 9 |
Analysis population for the primary outcome, as defined in the registry: Full analysis set - global study - Part A
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: Full analysis set - Global study
| Characteristic | Unit | Nefecon | Placebo Oral Capsule | Total |
|---|---|---|---|---|
| Participants analysed | 182 | 182 | 364 | |
| Age, Continuous | years | 43.8 (SD 10.78) | 41.6 (SD 10.65) | 42.7 (SD 10.76) |
| Sex: Female, Male: Female | Participants | 65 | 59 | 124 |
| Sex: Female, Male: Male | Participants | 117 | 123 | 240 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 43 | 40 | 83 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 138 | 137 | 275 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 5 | 6 |
| Baseline Urine protein to creatinine ratio (UPCR) | g/gram | 1.300 (0.902 to 1.764) | 1.264 (0.877 to 1.737) | 1.282 (0.892 to 1.752) |
| Baseline Estimated glomerular filtration rate (eGFR) | ml/min/1.73 m2 | 56.006 (45.497 to 70.972) | 55.565 (45.957 to 67.735) | 55.785 (45.929 to 69.839) |
6. Primary Endpoint
The registry lists the primary outcome as Part A: Ratio of Urine Protein to Creatinine Ratio (UPCR) at 9 Months Compared to Baseline, measured over 9 months.
| Element | Registry entry |
|---|---|
| Result type | Geometric Least Squares Mean |
| Measure of spread | 96% Confidence Interval |
| Unit | ratio |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the ratio of UPCR at 9 months to UPCR at baseline. UPCR is the urine protein-to-creatinine ratio, and the registry specifies that it was based on 24-hour urine collections. A ratio expresses the follow-up measurement relative to the starting measurement; the analysis compared the geometric least-squares mean ratios between the treatment groups.
Protein measured in urine is relevant to kidney disease assessment, so a follow-up UPCR measure can capture a change in urinary protein over the assessment period. Using a ratio to baseline makes the endpoint a relative measure rather than a comparison of follow-up values alone. The registry’s endpoint description defines the ratio as UPCR at 9 months divided by UPCR at baseline.
This measure is not the same as a direct count of kidney failure events or a measure of how long participants lived without such an event. The study also listed later eGFR and rescue-medication outcomes, but these address different questions. The primary result therefore describes the comparative UPCR ratio at the stated time point; by itself, it does not establish what happened to every participant’s longer-term kidney function.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
In Part A, the reported ratio of geometric least-squares means comparing Nefecon with placebo was 0.73. Its 96% confidence interval was 0.61 to 0.88, and the reported p-value was < 0.001. Because the comparison is below 1, the model-based estimate indicates a lower UPCR ratio relative to baseline in the Nefecon group than in the placebo group. The interval gives a range of values compatible with the analysis under its statistical assumptions; it does not show the range of individual participant outcomes.
The group estimates were 0.69 for Nefecon, with a 96% confidence interval of 0.61 to 0.79, and 0.95 for placebo, with a 96% confidence interval of 0.83 to 1.08. These are group-level geometric least-squares mean ratios. They should not be read as raw averages or as evidence that every participant had the same change. The registry identifies an MMRM model for the comparison but does not report enough detail to reconstruct the model specification.
The result is statistically distinguishable from a comparison value of 1 under the reported model and test, as reflected in the confidence interval and p-value. Statistical evidence of a group difference is not, on its own, a judgment about clinical importance. The registry record does not give a threshold for a clinically important UPCR change, and the primary endpoint is not a direct measure of end-stage renal disease.
Part B includes outcomes with different measures and analysis approaches. The posted secondary results include a Cox proportional hazards analysis for time to 30% reduction in eGFR and for time to rescue medication, and a logistic regression result for absence of microhematuria. Simple unadjusted re-calculations are also reported for some binary outcomes. Those estimates are not interchangeable: a hazard ratio concerns event timing, an odds ratio concerns odds, and a risk difference compares event proportions. The estimates and tests should be interpreted according to their own outcome definitions and methods.
The secondary analyses are additional evidence about outcomes beyond the primary endpoint, but they do not replace it. The registry record does not report a multiplicity adjustment plan for these secondary tests. Consequently, nominal p-values from multiple secondary comparisons should be read cautiously rather than as if each were the sole prespecified test. Neither the primary nor secondary results alone establish effects outside the studied population, treatment period, and outcomes recorded.
9. Statistical Methods Explained
What does the primary estimate represent?
The primary analysis uses a ratio of geometric least-squares means. A ratio compares one quantity with another; a value of 1 represents equality on the ratio scale. A value below 1 indicates that the numerator is lower than the reference quantity, while a value above 1 indicates it is higher. Here, the reported comparison of 0.73 is the model-based ratio for Nefecon relative to placebo for the UPCR ratio endpoint.
Geometric means are suited to measurements analyzed on a multiplicative scale, where relative rather than additive differences are of interest. A least-squares mean is a model-based estimate, rather than necessarily the unadjusted arithmetic average of the observations. The registry identifies the comparison method as an MMRM model. The full model specification, including its covariates, covariance structure, and missing-data assumptions, is not reported in the registry record.
How should the confidence interval and p-value be read?
A confidence interval conveys uncertainty around an estimate under the assumptions of the statistical model. The primary comparison has a 96% confidence interval from 0.61 to 0.88. Since that interval does not include 1, its range is consistent with a difference between groups on the ratio scale under the reported analysis. A confidence interval is not a range containing the true value with certainty, nor does it describe the spread of individual responses.
The reported p-value is < 0.001. A p-value describes how compatible the observed data are with a specified null model, assuming the analysis assumptions hold. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry gives a 96% interval for this endpoint; the reason for that confidence level is not reported in the registry record.
Why do the secondary results use different measures?
Time-to-event outcomes account for when an event occurs, as well as whether it occurs during the observation period. The registry reports Cox proportional hazards models for time to 30% reduction in eGFR and time to receiving rescue medication. A hazard ratio compares event rates over time under the model; it is not a ratio of event counts or a difference in the proportion of participants with an event. The proportional-hazards assumption and other model details are not reported in the registry record.
The microhematuria outcome is reported using logistic regression and an odds ratio. Odds compare the probability of an outcome with the probability of its absence; an odds ratio compares those odds between groups. The simple unadjusted re-calculations for binary outcomes use risk differences, which compare proportions directly. These measures can differ in size and interpretation, so a risk difference should not be treated as if it were an odds ratio or hazard ratio.
For the time-to-30% eGFR-reduction outcome, the simple unadjusted comparison is a risk difference with a confidence interval and unadjusted p-value. The registry also reports a Cox model result. The rescue-medication outcome likewise has a simple risk-difference re-calculation and a Cox model result. These are analyses of the same general outcomes using distinct estimands and methods, not necessarily identical estimates. The microhematuria result has a simple risk-difference re-calculation alongside a logistic-regression odds ratio.
What do the planning illustrations mean?
The sample-size illustrations use the observed effect as a planning reference, then consider detecting the full observed effect or a stated fraction of it. They are planning illustrations, not observed power and not evidence that the study was designed using those assumptions. The assumptions listed are a two-sided significance level of 0.05, equal allocation, and a normal approximation. For time-to-event outcomes, the illustrations are expressed as total events; for other outcomes, they are expressed as participants per arm. The trial’s own sample-size justification is not reported in the registry record.
The illustration is sensitive to the effect size chosen: planning for a smaller fraction of the observed effect requires a larger study under the stated framework. That is a general feature of sample-size planning, not a claim about the trial’s design. The actual observed effect can be uncertain, and using it as a planning reference does not establish that the same effect would recur in another study.
What cannot be established from these methods entries?
The registry record does not report the detailed statistical analysis plan, a multiplicity procedure, interim analyses, or specific missing-data methods. The primary population is named as the full analysis set for Part A, but the criteria defining that set are not reported in the registry record. These omissions limit how completely an independent reader can assess model choices, sensitivity analyses, and the handling of incomplete follow-up.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| MMRM model | Ratio of geometric LS means 0.73 | 0.61 to 0.88 | < 0.001 |
The registry reports the primary comparison as an MMRM model estimate: a ratio of geometric least-squares means of 0.73, with a 96% confidence interval of 0.61 to 0.88 and p < 0.001. This is the sponsor-reported model-based analysis. The group-level estimates are also reported separately, but they are not a substitute for the adjusted comparison from the model.
For the secondary outcomes with detailed results, the registry includes sponsor-reported Cox proportional hazards analyses for time to 30% reduction in eGFR and time to rescue medication, and a logistic regression analysis for absence of microhematuria. Simple unadjusted re-calculations are also reported for these outcomes. These re-calculations are not the same as the sponsor’s model-based analyses: they use different measures and do not incorporate the same modeling approach.
The posted record does not identify a discrepancy between the reported sponsor analysis and the calculations. Where both forms of analysis appear, the model-based result should be read as the registry’s reported analysis, while the simple re-calculation is supplementary and unadjusted. The registry does not report enough model detail to reproduce the sponsor’s analyses independently.
11. Multiplicity, Missing Data and Analysis Populations
The registry identifies the primary endpoint and reports its model-based result, but it does not report a detailed testing hierarchy or multiplicity adjustment for secondary outcomes. When several outcomes are tested, interpreting each nominal p-value as if it were the only planned test can overstate the strength of evidence across the whole group of results. Without a reported adjustment or prespecified hierarchy, secondary p-values are best treated as nominal and interpreted cautiously.
Missing-data handling is also not described in enough detail to assess its impact. An MMRM model is reported for the primary analysis, but the registry record does not specify the model’s assumptions about missing observations, the amount or pattern of missing data, or sensitivity analyses. The analysis population is named as the full analysis set for global Part A; the rules used to define that set are not reported in the registry record. Detailed populations and missing-data approaches for the secondary analyses are also not reported in the registry record.
The registry gives an enrollment of 365, while different outcome entries report their own analysis counts. These entries should not be assumed to represent identical sets of participants or identical follow-up. The registry does not explain all differences in analysis denominators or report participant flow in the registry record for these results.
Interim analyses and the trial’s sample-size justification are not reported in the registry record. The listed planning illustrations are not evidence of the original design rationale. Without the protocol or full analysis plan, the timing and governance of analyses, handling of multiplicity, missing-data assumptions, and any planned sensitivity analyses cannot be established from the registry record.
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 |
|---|---|---|---|
| Nefecon | 18 | 182 | 9.9% |
| Placebo Oral Capsule | 9 | 182 | 4.9% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Nefecon | 1 of 182 |
| Placebo Oral Capsule | 0 of 182 |
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 |
|---|---|
| Nefecon | 108 of 182 |
| Placebo Oral Capsule | 69 of 182 |
Most frequent serious adverse event terms
| Event term | Organ system | Nefecon | Placebo Oral Capsule |
|---|---|---|---|
| Acute kidney injury | Renal and urinary disorders | 1 of 182 | 2 of 182 |
| Corona virus infection | Infections and infestations | 2 of 182 | 0 of 182 |
| Pneumonia | Infections and infestations | 2 of 182 | 0 of 182 |
| Renal impairment | Renal and urinary disorders | 2 of 182 | 0 of 182 |
| Hypertension | Vascular disorders | 2 of 182 | 0 of 182 |
| Pulmonary embolism | Respiratory, thoracic and mediastinal disorders | 2 of 182 | 0 of 182 |
| Campylobacter colitis | Infections and infestations | 0 of 182 | 1 of 182 |
| Diverticulitis | Infections and infestations | 0 of 182 | 1 of 182 |
| Erysipelas | Infections and infestations | 1 of 182 | 0 of 182 |
| Nephrotic syndrome | Renal and urinary disorders | 1 of 182 | 0 of 182 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Nefecon | Placebo Oral Capsule |
|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 17 of 182 | 19 of 182 |
| Edema peripheral | General disorders | 28 of 182 | 7 of 182 |
| Headache | General disorders | 19 of 182 | 14 of 182 |
| Muscle spasms | Musculoskeletal and connective tissue disorders | 22 of 182 | 7 of 182 |
| Hypertension | Vascular disorders | 21 of 182 | 6 of 182 |
| Acne | Skin and subcutaneous tissue disorders | 20 of 182 | 2 of 182 |
| Upper respiratory tract infection | Infections and infestations | 10 of 182 | 10 of 182 |
| Nausea | Gastrointestinal disorders | 8 of 182 | 12 of 182 |
| Diarrhea | Gastrointestinal disorders | 9 of 182 | 10 of 182 |
| Dyspepsia | Gastrointestinal disorders | 13 of 182 | 4 of 182 |
Serious events with the highest arm-level rate: corona virus infection (1.1%), pneumonia (1.1%), acute kidney injury (1.1%), renal impairment (1.1%), hypertension (1.1%).
The safety entries report serious adverse events in 18 participants in the Nefecon group and 9 in the placebo group, with 182 participants at risk in each group. Other adverse events are reported for 108 and 69 participants, respectively. The registry also records 1 death in the Nefecon group and 0 in the placebo group. These counts describe what was recorded in the respective groups; they do not establish that study treatment caused an event or death.
The listed serious-event terms include corona virus infection, pneumonia, acute kidney injury, renal impairment, hypertension, and pulmonary embolism, each reported at 1.1%. The record does not provide arm-specific attribution for these listed terms in the registry record, so they should not be assigned to one group based on this information alone.
Adverse-event counts are descriptive and depend on the observation period, event definitions, and reporting procedures. The registry record does not provide further detail about event severity beyond the serious-event classification, relatedness assessments, exposure-adjusted rates, or the timing of events. The figures therefore support a limited account of reported events, not a complete comparative safety evaluation or a causal conclusion.
13. What the Result Does, and Does Not, Mean
The primary result indicates that, under the reported MMRM analysis, the UPCR ratio relative to baseline was lower in the Nefecon group than in the placebo group at 9 months. The confidence interval and p-value describe the statistical uncertainty and evidence for that comparison under the model. They do not mean that every participant had the same response or that the exact estimated value is known without uncertainty.
The endpoint is a urine protein measure, not a direct count of progression to end-stage renal disease. Although the trial’s broader aim concerned patients at risk of progression, the primary result alone does not show how the endpoint translates into long-term kidney outcomes, quality of life, or an individual participant’s prognosis. The secondary eGFR and rescue-medication outcomes address additional questions, but their results require separate interpretation and are subject to the limitations of secondary testing.
Statistical evidence should also be distinguished from clinical importance. The registry record does not report a threshold for a clinically important difference in UPCR, so the magnitude’s clinical meaning cannot be determined from the p-value alone. The confidence interval is informative about precision at the group level, but it does not replace a clinical interpretation based on relevant outcome thresholds and broader evidence.
Finally, these findings apply to the studied population and the recorded treatment and assessment periods. The registry record does not establish whether the estimates generalize to people outside the described population or to different treatment settings. The data describe a comparison within this randomized study; they are not a guarantee of an individual outcome.
14. Why This Trial Matters Statistically
Statistically, the trial is notable for a defined primary comparison using a ratio endpoint and a model-based estimate. The reported 96% confidence interval provides a way to assess the precision of the primary group comparison, while the MMRM analysis reflects a model-based approach rather than a simple comparison of raw group means. The registry also names the analysis population, allowing readers to understand which Part A population the primary result is intended to describe.
The record includes outcomes beyond the primary endpoint, spanning eGFR, rescue medication, urine measures, and microhematuria. That range illustrates why clinical trials require clear distinctions among endpoints: a measure of urinary protein, a time-to-event outcome, and a binary outcome each answer a different question and call for different statistical summaries. A favorable-looking estimate for one measure does not automatically imply the same result for another.
The secondary results also show why it matters to distinguish sponsor-reported models from simple unadjusted re-calculations. Hazard ratios, odds ratios, and risk differences have different interpretations, and they can be affected differently by modeling and follow-up. Presenting the method alongside the estimate helps readers avoid treating these measures as interchangeable.
Finally, the registry makes some key reporting gaps visible. The full statistical plan, multiplicity approach, missing-data details, and sample-size justification are not reported in the registry record. These omissions constrain independent assessment of the analysis choices and the strength of conclusions across multiple endpoints. A careful reading therefore considers both the primary evidence and the limits on reconstructing the broader analysis strategy.
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 does not provide the full statistical analysis plan, so important details of the MMRM specification and the secondary models cannot be independently assessed. Covariates, model structure, assumptions, and sensitivity analyses are not reported in the registry record. The record also does not describe how missing observations were handled or provide the extent and pattern of missing data.
The record does not report a multiplicity adjustment or a hierarchy for secondary outcomes. This limits the interpretation of nominal secondary p-values, particularly when multiple endpoints and analyses are considered. Numerical results are not reported in the registry record for several listed secondary outcomes, so the detailed results do not describe every outcome named in the study.
The primary UPCR endpoint is assessed at 9 months, while some other outcomes are followed over 2 years. UPCR is not itself a direct event measure of end-stage renal disease, and the registry record does not provide a threshold for clinical importance. The primary estimate should therefore be interpreted as evidence about the stated urine measure and time point, not as a direct estimate of long-term kidney outcomes.
Safety information is presented as counts, without further details in the registry record about event timing, relatedness, exposure-adjusted rates, or arm-specific attribution for the listed serious-event terms. The registry also does not report the trial’s sample-size justification, interim analyses, or full participant flow. These reporting gaps limit assessment of precision, robustness, and generalizability beyond the enrolled study population.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Efficacy and Safety of Nefecon in Patients With Primary IgA (Immunoglobulin A) Nephropathy — NCT03643965.
- Registry record last updated 2024-12-03; status last verified 2024-11.
- Results first posted 2024-12-03.
- 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
NCT03643965 is a completed Phase 3 randomized, quadruple-masked, parallel-group study of Nefecon versus placebo in patients with primary IgA nephropathy at risk of progression despite maximum tolerated RAS blockade. The listed regimen was Nefecon 16 mg once daily by mouth for 9 months, compared with placebo once daily for 9 months. Enrollment was 365.
The primary endpoint was the ratio of UPCR at 9 months to baseline, based on 24-hour urine collections. The reported MMRM comparison of geometric least-squares means was 0.73, with a 96% confidence interval of 0.61 to 0.88 and p < 0.001. Part B included outcomes followed over 2 years. The registry record reports selected secondary analyses and adverse-event counts, but does not report the full statistical plan, multiplicity procedure, missing-data methods, or sample-size justification.