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 Autologous Neo-Kidney Augment (NKA) in Patients With Type 2 Diabetes and Chronic Kidney Disease (CKD) (NCT02525263), a na phase 2 study. The primary outcome is Procedure and/or Product Related Serious Adverse Events (AE's) Through 12 Months Following the Final NKA Implantation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02525263 |
| Phase | Phase 2 |
| Condition | Chronic Kidney Disease, Type 2 Diabetes |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Prokidney |
| Results posted | Yes |
2. Clinical Question
Population
The registry record describes people with type 2 diabetes and chronic kidney disease. Enrollment was 1. The record does not report additional eligibility details or describe the enrolled participant's baseline clinical characteristics.
Intervention
The intervention was Neo-Kidney Augment, an autologous product made using selected renal cells obtained from a kidney biopsy. The study summary says participants would receive up to two injections, at least 6 months apart. The record identifies a group named NKA Augment Second Dose.
Comparator
There was no concurrent comparator group: the design is listed as single-group, with allocation recorded as NA and masking listed as none. The treatment experience therefore cannot be interpreted as a randomized comparison with another treatment or with no intervention.
Primary question
The primary endpoint counts procedure- and/or product-related serious adverse events through 12 months following the final NKA implantation. The question is whether such events were reported during that specified follow-up. The record reports 1 serious adverse event among 1 participant at risk in the NKA Augment Second Dose group. It does not provide a controlled estimate of comparative safety or an efficacy estimate for kidney outcomes.
The study is identified as NCT02525263 and is titled as a Phase II, open-label safety and efficacy study. Its primary endpoint is safety-focused, while renal-specific laboratory assessments are listed as a secondary outcome through 12 months following the last implantation. No analysis results for that secondary outcome are reported in the registry record. The clinical question is therefore narrower than whether NKA changes kidney function: the reported primary measure concerns serious adverse events attributed to the procedure and/or product within the specified follow-up period.
3. Trial Design
This was a Phase II, open-label, single-group study of Neo-Kidney Augment in people with type 2 diabetes and chronic kidney disease. The registry record lists allocation as NA and masking as none. There is no separate control arm in the recorded design, so outcomes are descriptive rather than estimates from a randomized treatment comparison. Enrollment is recorded as 1.
The intervention is described as an autologous product made from selected renal cells obtained from the participant's kidney biopsy. The study summary states that participants would receive up to two NKA injections at least 6 months apart. The arm description names a second-dose group, but the record does not establish from that label alone how much of the planned treatment schedule was completed or how follow-up was conducted for the enrolled participant.
The study start is recorded as 2016-07, primary completion as 2017-05, and status as terminated. Those registry dates describe the study record; they do not explain why the study was terminated. The reason for termination is not reported in the registry record.
The primary endpoint is a count of procedure- and/or product-related serious adverse events through 12 months following the final implantation. A renal-specific laboratory assessment through 12 months following the last implantation is listed as a secondary outcome. The registry record lists 6 outcome measures but reports no outcome analyses. It does not report a statistical analysis plan, analysis populations, or details sufficient to reconstruct how all listed outcomes were evaluated.
As a general statistical point, an open-label, single-group study can describe events observed among treated participants, but it cannot by itself separate treatment-related risk from background events or other explanations. With enrollment of 1, the record offers a very limited descriptive safety observation rather than a stable estimate of event frequency across a broader population.
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: The only enrolled patient was assigned to the only treatment arm. There was no significant event prior to assignment.
Overall Study
| Stage | NKA Augment Second Dose |
|---|---|
| STARTED | 1 |
| COMPLETED | 1 |
| NOT COMPLETED | 0 |
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 single US patient who had previously received an NKA injection was enrolled in this clinical trial.
| Characteristic | Unit | NKA Augment Second Dose |
|---|---|---|
| Participants analysed | 1 | |
| Age, Customized: 59 years old | Participants | 1 |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 0 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Procedure and/or Product Related Serious Adverse Events (AE's) Through 12 Months Following the Final NKA Implantation, measured over 12 months following final implantation.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Serious adverse events |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint counts procedure- and/or product-related serious adverse events through 12 months following the final NKA implantation. The record says these events were measured by adverse-event reporting. This makes the endpoint a count of events, rather than a change in a laboratory value or a comparison between treatment groups. No primary endpoint analysis is reported in the registry record.
As a general concept, a serious adverse event endpoint is used to organize safety observations around events considered serious, while a defined follow-up period specifies when those events are counted. Attribution to a procedure and/or product also makes the stated endpoint narrower than a count of every event occurring during follow-up. The registry entry does not provide further operational details about seriousness, attribution decisions, event handling, or the exact counting rules.
The posted safety data list 1 participant at risk and 1 participant affected in the NKA Augment Second Dose group. These figures should be read as the recorded group-level summary, not as a comparison with an untreated group. The registry record also lists worsening hypertension and surgical pain of the left kidney as serious-event terms, each with 100.0%. It does not explain the denominator or clarify how those terms relate to the overall serious-adverse-event count.
The endpoint is relevant to safety description, but the record does not report an efficacy result for the renal laboratory outcome. The primary endpoint therefore does not establish whether kidney-related measures changed, nor does the single-group design provide a comparative estimate of safety.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted results contain a small amount of directly interpretable safety information. In the NKA Augment Second Dose group, the registry record lists 1 participant at risk and 1 participant affected by a serious adverse event. The listed serious-event terms are worsening hypertension and surgical pain of the left kidney, each recorded as 100.0%. These entries describe what the registry reports for this group; they do not provide an estimate of comparative risk.
The meaning of the terms and percentages is constrained by the information recorded. The record does not specify the denominator used for the percentages, whether each term represents an event or a participant with that event, or whether the listed terms account for the overall serious-adverse-event count. It would therefore be inappropriate to infer from these entries that there were separate affected participants or to derive a broader event rate. Enrollment was 1, but the relationship between enrollment, the group-specific risk denominator, the event terms, and completion of follow-up is not described in enough detail to resolve those questions.
The endpoint specifies events through 12 months following the final implantation. A group label referring to a second dose does not establish whether the participant received all planned treatment or completed the full endpoint follow-up. The record does not report the timing of the listed events relative to implantation, the duration of observed follow-up, or whether any events occurred outside the stated endpoint window.
There is no concurrent control group, and the study is open-label. As a general statistical point, a single-group observation can document that an event was recorded, but it cannot estimate the difference in event risk between NKA and another treatment or no treatment. It also cannot distinguish an effect of the product or procedure from background illness, other care, or chance. The record does not report an efficacy analysis, despite the study title describing safety and efficacy.
No confidence interval, hypothesis test, or outcome analysis is reported in the registry record. That absence means the posted information does not quantify statistical uncertainty around a treatment effect. With enrollment of 1, the event description is especially limited as a basis for generalization. The result is best understood as a registry safety observation in the listed group, not as evidence for a precise rate, a causal conclusion, or an efficacy effect.
The study status is terminated, with a start date of 2016-07 and primary completion recorded as 2017-05. The reason for termination is not reported in the registry record. The status alone should not be treated as an explanation of the observed adverse events or as a statistical conclusion.
9. Statistical Methods Explained
The registry record identifies the study as Phase II, open-label, and single-group. Allocation is recorded as NA, masking as none, and enrollment as 1. These design features determine what kinds of statistical conclusions are possible. There is no randomized comparison in the record, so a between-group treatment effect cannot be estimated from these results. The available safety information is descriptive.
What does a count endpoint represent?
The primary endpoint is a number of procedure- and/or product-related serious adverse events during a stated follow-up window. A count endpoint describes how many events were recorded according to the endpoint definition. It is not automatically the same as the number of participants affected: a participant may, in principle, contribute more than one event, and an event term may be recorded in ways that are not explained in the registry entry. The record does not give the event-counting rules or a full breakdown linking each event term to the overall count.
The posted group summary reports 1 at risk and 1 affected for serious adverse events in the NKA Augment Second Dose group. Those are the entries to report, without converting them into a different measure. No additional rate, ratio, or comparative estimate is reported. In general, a count or proportion can be difficult to interpret when its denominator, observation time, and event definitions are not fully specified. Here, the group information does not resolve all of those details.
Why does the design affect interpretation?
In a randomized comparison, assignment to different groups can support estimation of a treatment contrast, subject to the trial's conduct and analysis. This study is listed as single-group and open-label, with no comparator. Its event record can describe observations after NKA treatment, but it cannot establish what would have happened to the same participants under another treatment or without NKA. Without a concurrent comparator, differences from an external expectation would also require assumptions not reported in the registry record.
Open-label means masking is not reported for this study; the registry specifically lists masking as none. As a general statistical consideration, knowledge of treatment can affect event reporting or assessment, depending on the outcome and its ascertainment. The record does not describe procedures used to reduce or assess any such influence. This is a limitation to keep in mind, not evidence that reporting was biased.
What would uncertainty estimates add?
A confidence interval is a general statistical tool for expressing uncertainty around an estimated quantity. For an event frequency, it can show how imprecise an estimate may be; for a treatment comparison, it can show uncertainty around the contrast. No confidence interval, hypothesis test, or analyzed treatment effect is reported in the registry record. There is consequently no posted uncertainty interval to interpret, and no basis for reconstructing one from a complete analysis specification.
In general, sparse event data produce limited information for estimating event frequencies or comparing groups. The small enrollment recorded further restricts how much can be learned about variation across participants. That does not change what the record reports about the listed group, but it prevents treating the observation as a precise estimate applicable to a wider population.
How should planning calculations be read?
Sample-size illustrations are planning scenarios, not observed power and not a description of the trial's own design. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. For time-to-event illustrations, the stated quantity is a total number of events; other illustrations are expressed as participants per arm. These assumptions do not turn this single-group study into a two-arm comparison, and no result from a planning illustration is an observed trial outcome.
The record does not report a protocol-based sample-size justification or explain the basis for a prospective target. It also does not report a statistical analysis plan that would connect a planning scenario to a prespecified hypothesis. Because the registry lists no outcome analyses and the design is not reduced to one comparison, planning figures should not be taken as proof of achieved precision or evidence of treatment effect.
Why does over-dispersion matter in general?
For count outcomes, statistical models sometimes assume that the variability in counts follows a particular relationship to their average. Over-dispersion means the observed variation is greater than that assumed by a simple count model. If present and ignored, uncertainty estimates can be too small. This is a general consideration for count data; the registry record does not report a count model, a dispersion assessment, or an analysis from which over-dispersion can be evaluated. No conclusion about it can be drawn for this study.
Overall, the statistical methods actually used beyond adverse-event reporting are not reported in the registry record. The record does not provide model specifications, covariate adjustment, a hypothesis-testing plan, or analysis results. Accordingly, the posted figures should be read as registry summaries rather than as the output of a fully described inferential analysis.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 6 outcome measures, including the primary serious-adverse-event endpoint and a secondary renal-specific laboratory assessment through 12 months following the last implantation. It reports no outcome analyses. A statistical analysis plan explaining how these outcomes were prioritized or evaluated is not reported in the registry record.
Multiplicity refers, in general, to the interpretive issue that can arise when several outcomes or statistical tests are examined. Without a stated plan, readers cannot determine whether any adjustment or other strategy was intended to address multiple testing. The record does not report such an approach, and no reported analysis is available to assess how multiplicity affected the results.
Missing-data handling is also not reported in the registry record. The entry does not describe whether outcome information was incomplete, how incomplete follow-up was handled, or whether any imputation or sensitivity analysis was conducted. The endpoint has a stated follow-up window, but the actual follow-up achieved and the handling of participants without complete observation are not described.
The analysis populations are not reported in the registry record. In particular, the record does not define which participants would be included in each outcome analysis or how treatment exposure and follow-up would be accounted for. With enrollment of 1, there is little information to characterize differences between possible analysis populations, but no assumptions about such populations should be made from that fact alone.
Interim analyses and stopping rules are not reported in the registry record. The status is terminated, but that status does not establish whether a planned stopping rule was used or why the study ended. The reason for termination is not reported in the registry record.
11. 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 |
|---|---|---|---|
| NKA Augment Second Dose | 1 | 1 | 100.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| NKA Augment Second Dose | 0 of 1 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| NKA Augment Second Dose | 1 of 1 |
Most frequent serious adverse event terms
| Event term | Organ system | NKA Augment Second Dose |
|---|---|---|
| Worsening hypertension | Cardiac disorders | 1 of 1 |
| Surgical pain of the left kidney | Surgical and medical procedures | 1 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | NKA Augment Second Dose |
|---|---|---|
| Worsening of hyperparathyroidism | Endocrine disorders | 1 of 1 |
| Worsening of chronic kidney disease | Renal and urinary disorders | 1 of 1 |
Serious events with the highest arm-level rate: worsening hypertension (100.0%), surgical pain of the left kidney (100.0%).
The primary endpoint concerns procedure- and/or product-related serious adverse events through 12 months following the final NKA implantation. In the NKA Augment Second Dose group, the registry record lists 1 participant at risk and 1 participant affected. The serious-event terms listed are worsening hypertension and surgical pain of the left kidney, each recorded as 100.0%.
These are descriptive safety entries. The record does not explain the denominator for the term percentages, whether the terms refer to events or participants, or how each term maps to the overall endpoint count. They should not be added together or interpreted as representing separate participants. The record also does not report event timing, duration of follow-up actually observed, or further detail about attribution to the procedure and/or product.
As a general statistical point, a serious-event count and a percentage are only interpretable in relation to their definitions, denominator, and observation period. The endpoint supplies a follow-up window, but details about event ascertainment and completed follow-up are not reported in the registry record. The group summary does not provide a comparator, so it cannot show whether event risk was higher or lower than it would have been under another approach.
Enrollment was 1, and the record contains no reported statistical analysis or uncertainty interval. The figures therefore describe the registry entry for this group and should not be treated as a precise estimate of safety in a broader population.
12. What the Result Does, and Does Not, Mean
The registry record documents an open-label, single-group Phase II study of Neo-Kidney Augment in people with type 2 diabetes and chronic kidney disease. It records enrollment of 1 and reports 1 participant at risk and 1 affected by a serious adverse event in the NKA Augment Second Dose group. Worsening hypertension and surgical pain of the left kidney are listed as serious-event terms, each with 100.0%.
Those observations do not establish a comparative safety result. There is no concurrent comparator group, and the record does not report a treatment contrast, confidence interval, or hypothesis test. The group-level entries cannot show whether the frequency of serious events differs from what would occur with another treatment or without NKA. They also do not establish that every listed term represents a different participant or event.
The primary endpoint is about serious adverse events attributed to the procedure and/or product during follow-up through 12 months after final implantation. It is not a direct measure of kidney function. Although renal-specific laboratory assessment is listed as a secondary outcome, its analysis result is not reported in the registry record. The record therefore does not provide an efficacy estimate for renal laboratory outcomes.
As a general statistical point, observations from a very small single-group study can identify events recorded in that study, but they provide little information about how consistently such events occur across a broader population. Lack of a reported analysis also means the uncertainty around any treatment effect is not quantified. The record does not report enough detail about event definitions, completed follow-up, or analysis populations to resolve these limitations.
The study status is terminated. The reason for termination is not reported in the registry record, so the status does not explain the safety entries or imply a conclusion about NKA. The most defensible reading is limited: the registry describes a serious adverse event in the listed treatment group, but does not establish a causal effect, a comparative risk, or a kidney efficacy result.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the difference between recording an outcome and estimating a treatment effect. The registry records a serious adverse event in the NKA Augment Second Dose group, but the study has a single-group, open-label design and enrollment of 1. A descriptive observation is not the same as a comparative estimate with a control group.
The endpoint is also specific in ways that matter for interpretation: it counts procedure- and/or product-related serious adverse events through 12 months following the final implantation. The record's listed serious-event terms add clinical detail, but the denominator and the relationship between those terms and the overall count are not explained. That makes it important to distinguish reported entries from conclusions that the data cannot support.
As a general lesson, sparse outcomes and incomplete reporting limit the precision and reproducibility of statistical interpretation. Clear definitions of event counting, observation time, analysis populations, missing-data handling, and analysis methods help readers understand what a reported count means. Those details are not reported in the registry record. Nor are outcome analyses or a statistical analysis plan reported.
The study also demonstrates why efficacy and safety claims should be tied to the measured endpoint. The primary endpoint concerns serious adverse events; a renal-specific laboratory assessment is listed separately, without reported analysis results. The record therefore cannot answer a kidney efficacy question from the primary safety data.
These limitations do not erase the value of documenting an event. They define the scope of what the record can support: a limited safety description in the listed group, rather than a precise estimate or a causal comparison.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
Several trial-specific limitations constrain interpretation. The study is listed as single-group, open-label, and without masking, with allocation recorded as NA. There is no concurrent comparator, so the registry results cannot estimate a difference in safety or efficacy between NKA and another approach. Enrollment was 1, sharply limiting the descriptive information available about variation across participants.
The primary endpoint is defined as procedure- and/or product-related serious adverse events through 12 months following the final implantation. The record does not report event-level detail, exact attribution procedures, the denominator used for the serious-event terms, or the participant's completed follow-up. It is therefore not possible to determine from the entry how the listed terms relate to the overall event count or whether follow-up covered the full stated period.
The group is named NKA Augment Second Dose, while the study summary describes up to two injections at least 6 months apart. The record does not establish the treatment schedule completed by the participant. The reason for termination is not reported in the registry record, so the study status cannot be interpreted as explaining either treatment exposure or the safety observations.
Although a renal-specific laboratory assessment is listed as a secondary outcome, its result is not reported in the registry record. The record lists 6 outcome measures but reports no outcome analyses, analysis populations, statistical analysis plan, missing-data methods, or multiplicity approach. It also does not report confidence intervals or hypothesis tests. The statistical methods beyond adverse-event reporting are therefore unclear.
Finally, the record does not provide enough information to evaluate how representative the enrolled participant was of the broader population described by the condition labels. These limitations make the posted information a narrow registry observation, not a basis for a stable general estimate.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Autologous Neo-Kidney Augment (NKA) in Patients With Type 2 Diabetes and Chronic Kidney Disease (CKD) — NCT02525263.
- Registry record last updated 2021-04-23; status last verified 2021-03.
- Results first posted 2021-04-23.
- 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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18. Record Summary
NCT02525263 is a Phase II, open-label, single-group study of Neo-Kidney Augment in people with type 2 diabetes and chronic kidney disease. The sponsor is Prokidney. The intervention is described as an autologous product made from selected renal cells obtained from a kidney biopsy. The study summary describes up to two injections at least 6 months apart.
The registry lists enrollment of 1, a study start of 2016-07, primary completion in 2017-05, and status as terminated. The primary endpoint counts procedure- and/or product-related serious adverse events through 12 months following final implantation. The NKA Augment Second Dose group reports 1 participant at risk and 1 affected; worsening hypertension and surgical pain of the left kidney are each listed with 100.0%.
No outcome analyses are reported. The renal-specific laboratory assessment is listed as a secondary outcome, but its result is not reported in the registry record. The reason for termination, statistical analysis plan, analysis populations, and missing-data methods are also not reported.