Evaluating ALLN-177 for Reducing Urinary Oxalate Excretion in Calcium Oxalate Kidney Stone Formers With Hyperoxaluria: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating ALLN-177 for Reducing Urinary Oxalate Excretion in Calcium Oxalate Kidney Stone Formers With Hyperoxaluria (NCT02289755), a na phase 2 study. The primary outcome is Change From Baseline Period to Treatment Period 24-hour Urinary Oxalate Excretion.

2. Clinical Question

The study focused on urinary oxalate excretion, measured in mg/day, in people with recurrent calcium oxalate stones and hyperoxaluria. Its stated purpose was to evaluate the effect of ALLN-177 on that measure. The primary outcome was defined as the baseline value minus the treatment value: baseline was the average of Days 2 and 3, while the treatment value was the mean of Days 5, 6, and 7. Under this definition, a positive change would correspond to a lower treatment-period value than baseline; the registry record does not report the observed change.

The design does not estimate a difference between ALLN-177 and an untreated or active comparator group. It describes measurements in the same study group across two periods. As a result, the clinical question that can be addressed by the design is limited to the observed within-participant change over those periods. Whether any observed change would be attributable to treatment cannot be established from this design alone.

3. Trial Design

This was a Phase 2, multicenter, open-label, single-arm study. The registry record lists allocation as not applicable and masking as none. It records an enrollment of 16 and a completed study status. The study start is listed as 2014-09 and primary completion as 2015-01. The number of participating centers is not reported in the registry record.

The study group comprised recurrent calcium oxalate stone formers with enteric or idiopathic hyperoxaluria. ALLN-177 was the listed intervention. Participants took 5 capsules orally with meals, up to 3 times daily, for 4 consecutive days. There was no parallel control arm and no random allocation between treatments. The registry record therefore describes a before-and-during-treatment assessment rather than a randomized treatment comparison.

The primary outcome timeframe is listed as 7 days. Baseline urinary oxalate was defined using the average of Days 2 and 3, and treatment-period urinary oxalate using the mean of Days 5, 6, and 7. The record states that all 16 participants completed treatment and were included in the primary analysis population. It does not report further detail about the timing or conduct of measurements beyond these definitions.

Open-label means that masking was not used. The registry record does not report additional procedures for limiting measurement or assessment bias. It also does not report the rationale for the enrollment target, eligibility criteria in detail, site count, or a full protocol description. Those details should not be inferred from the study title or design label.

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: History of ≥1 calcium oxalate kidney stone within the last 2 years, secondary hyperoxaluria and a mean urinary oxalate of ≥36 mg/day

Baseline Period [No Treatment, 3 Days]

ALLN-177 Treatment Period [4 Days]

Follow up Period [4 Days]

Analysis population for the primary outcome, as defined in the registry: All Participants (N=16) completed treatment and were included in the analysis population.

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: All subjects (N=16) were included in the analysis.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline Period to Treatment Period 24-hour Urinary Oxalate Excretion, measured over 7 days.

The primary endpoint was change in 24-hour urinary oxalate excretion from the baseline period to the treatment period, expressed in mg/day. This is a continuous measure, and the registry identifies the summary measure as the mean with standard deviation. The baseline value was the average of measurements on Days 2 and 3; the treatment value was the mean of measurements on Days 5, 6, and 7. Change was defined as baseline minus treatment.

Because the endpoint directly measures urinary oxalate excretion, it corresponds to the study’s stated objective of evaluating whether ALLN-177 changes urinary oxalate. Comparing measurements within the same participants can describe how the outcome varies between the two specified periods. A positive value under the registry’s subtraction order would indicate a lower treatment-period measurement than baseline, while a negative value would indicate a higher treatment-period measurement. The observed endpoint value is not reported in the registry record, so the direction and size of the study’s result cannot be stated.

As a general statistical point, a mean describes the average measurement in the analysis group, while a standard deviation describes variation among observations. Neither alone gives the precision of the estimated mean change; that requires additional information, such as a confidence interval. The registry record does not report a confidence interval for this endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a continuous measurement: 24-hour urinary oxalate excretion in mg/day. The registry specifies a mean and standard deviation as the descriptive summaries. In general, a mean gives the average value in the analysis group, and a standard deviation describes how much individual measurements vary around that average. These summaries describe the observed data; they do not, on their own, establish the precision of an estimated treatment-period change.

The outcome is defined as a within-participant change, calculated conceptually by subtracting the treatment-period value from the baseline value. The baseline value is the average of Days 2 and 3, and the treatment value is the mean of Days 5, 6, and 7. Because the subtraction is baseline minus treatment, a positive change represents a lower treatment-period value. This direction follows from the endpoint definition and is not a reported study result.

In general, a confidence interval gives a range of values compatible with the data under the statistical method used and conveys uncertainty around an estimate. A narrow interval indicates greater precision than a wide interval, while the interval’s location helps show which effect sizes remain compatible with the data. The registry record does not report a confidence interval for the primary outcome. A p-value, if reported, would address compatibility with a specified null hypothesis under assumptions of a test; it would not measure the probability that treatment works or establish clinical importance. No primary outcome p-value or named statistical test is reported in the registry record.

The study’s single-arm design matters when interpreting any within-participant change. As a general point, paired measurements can account for stable differences between participants because each participant contributes measurements to both periods. However, without a concurrent comparator group, a before-and-during-treatment change cannot distinguish a treatment-associated change from other influences that vary over time. Open-label conduct also means masking was not used; the registry record does not report other safeguards or adjustment procedures that would address possible measurement or assessment influences.

The registry record describes a separate sample-size planning illustration, not the design used to allocate participants in this single-arm study. Its 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 stated fraction of the observed effect. In general, such an illustration asks how many participants per arm would be needed under those assumptions for a hypothetical comparison. It is a planning calculation, not observed power and not evidence that the actual single-arm study had that power. The numerical planning outputs and the observed effect used as the basis for the illustration are not reported in the registry record.

As a general explanation, normal-approximation planning methods rely on assumptions about the distribution of the estimate and the variability used in the calculation. If the data depart from those assumptions, the resulting planning figures may not describe the operating characteristics of a real study well. The registry record does not report a diagnostic assessment of distributional assumptions or a more detailed sample-size justification. Because the actual study had no two-arm allocation, the hypothetical equal-allocation assumption should not be mistaken for a feature of the trial design.

The record identifies 16 participants as the analysis population and says that all completed treatment. It does not identify the statistical method used to estimate the mean change, explain how repeated measurements were combined beyond the stated period averages, or describe handling of missing observations. It also does not report covariate adjustment, subgroup analyses, interim analyses, or sensitivity analyses. Those methods should not be assumed.

For continuous outcomes, analysts may use different methods depending on the measurement distribution, dependence between repeated observations, and analysis objective. General methodological choices can affect standard errors and confidence intervals. The registry record does not specify which inferential approach was used for the primary outcome, so it is not possible to evaluate those choices or reproduce an inferential result from the record alone. The mean and standard deviation are listed as the intended summary, but no numerical primary outcome summaries are reported.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("ALLN-177")
n   <- c(16)
m   <- c(-13.92)
sp  <- c(18.37)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  ALLN-177  16  -13.920  18.370  -23.709  -4.131

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists the primary outcome of change in 24-hour urinary oxalate excretion and a secondary outcome of percent change from baseline to treatment in the same measure. It reports two outcome measures in total. It does not report results for either outcome, describe a hierarchy for testing them, or state whether any multiplicity adjustment was planned. In general, testing several outcomes can increase the chance of at least one apparently unusual result under a collection of null hypotheses. Whether that issue was addressed is not reported in the registry record.

The stated analysis population consists of all 16 participants, who are reported to have completed treatment and been included in the analysis. That statement does not give a complete account of missing data at the measurement level. The registry record does not say whether all scheduled urine measurements were available, how any incomplete measurement periods were treated, or whether any imputation or sensitivity analysis was used.

The record does not report an intention-to-treat population, a per-protocol population, or additional analysis populations beyond the participants who completed treatment and were included in the analysis. It also does not give exclusions from analysis or explain whether analysis decisions were made before or after reviewing outcome data. These details are not reported in the registry record and should not be inferred from the completion statement alone.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry record reports that 0 of 16 participants were affected by a serious adverse event in the ALLN-177 group. It also reports that 9 of 16 participants were affected by events in the other-adverse-event category. These are counts of participants affected, not necessarily counts of individual event occurrences. The registry record does not list the specific event terms in either category.

The reported serious adverse event figure describes what was recorded among the participants at risk in this study. It does not establish the absence of all safety concerns, and it does not show whether an event was caused by the intervention. The study was single-arm, so these figures do not provide a comparison with a separate control group. The record’s death field does not contain a reported count; deaths are therefore not reported in the registry record. Details such as event timing, severity beyond the serious-event classification, and relatedness are not reported in the registry record.

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

The registry record documents a completed Phase 2 study designed to measure urinary oxalate excretion before and during a short course of ALLN-177 in recurrent calcium oxalate stone formers with hyperoxaluria. It specifies a primary endpoint, the period measurements used to define it, and an analysis population of 16 participants who completed treatment. It also reports serious and other adverse-event participant counts.

The primary outcome result itself is not reported in the registry record. Consequently, the record does not show the average change, its direction, or its precision. It is not possible to state from these registry entries whether urinary oxalate excretion decreased or increased during treatment. No result for the listed secondary percent-change outcome is reported either.

Even if a within-participant change were available, a single-arm before-and-during-treatment design would describe change over time in this group rather than estimate a treatment effect against a concurrent comparator. General sources of change over time, including measurement variability, could not be separated from a treatment-associated change on the basis of this design alone. The lack of reported outcome estimates further limits interpretation.

The safety counts provide a description of events recorded among the study participants, not a comparative safety estimate. The event terms and attribution details are not reported in the registry record. Taken together, the record supports a description of the study’s design and measured outcomes, but it does not supply the primary efficacy result or enough comparative information to determine how the findings relate to outcomes without treatment.

14. Why This Trial Matters Statistically

This study is statistically useful to examine because it makes explicit the distinction between measuring change and establishing a comparative treatment effect. Its primary endpoint compares urinary oxalate excretion across baseline and treatment periods in the same participants. That design can describe within-group change, but it does not include a concurrent group that would help distinguish treatment-related change from changes that might occur over the same time without the intervention.

The registry record also illustrates why endpoint definitions matter. The direction of change depends on the subtraction order: baseline minus treatment means that positive values correspond to lower treatment-period measurements. The averaging windows are specified, so the intended summary can be understood even though the observed result is not reported. Clear definitions are necessary for interpreting a result, but they cannot replace the result itself.

The study enrolled 16 participants, all of whom are reported to have completed treatment and entered the analysis population. That accounting is informative about the analysis group, while leaving measurement-level missingness and the inferential method undescribed. The distinction between completion and complete outcome data is important in general: completing treatment does not by itself document that every scheduled measurement was available.

Finally, the registry’s planning illustration uses assumptions for a hypothetical two-arm calculation, while the actual study is single-arm. Keeping planning calculations separate from the observed design prevents sample-size illustrations from being mistaken for an analysis of trial power or a randomized comparison. Because the primary outcome estimate is not reported in the registry record, the central numerical result remains unavailable for interpretation.

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 main limitation for interpreting the posted record is that it does not report the primary outcome estimate, its standard deviation, a confidence interval, or a p-value. Without those results, neither the observed direction nor magnitude of change can be assessed. The secondary percent-change outcome is listed but its result is also not reported in the registry record.

The single-arm, open-label design has no concurrent comparator and no masking. A baseline-to-treatment change can therefore not, by itself, isolate the effect of ALLN-177 from other influences that may vary across periods. The study enrolled 16 participants, and the registry record does not provide individual data or an inferential uncertainty estimate with which to evaluate the stability of a group mean.

The record specifies the outcome time windows but does not report daily measurements, measurement-level completeness, or how missing observations were handled. It also does not describe the statistical test or model, adjustment variables, sensitivity analyses, multiplicity procedures, interim analyses, or a sample-size justification for the actual single-arm design. The number of study centers is not reported in the registry record, despite the multicenter designation.

Safety information is limited to participant counts in serious and other adverse-event categories. Event terms, timing, attribution, and the death count are not reported in the registry record. These omissions limit what can be concluded from the posted safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluating ALLN-177 for Reducing Urinary Oxalate Excretion in Calcium Oxalate Kidney Stone Formers With Hyperoxaluria — NCT02289755.
• Registry record last updated 2019-06-05; status last verified 2016-02.
• Results first posted 2016-04-27.
• 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.

19. Record Summary

NCT02289755 is a completed Phase 2, multicenter, open-label, single-arm study of ALLN-177 in recurrent calcium oxalate stone formers with enteric or idiopathic hyperoxaluria. Enrollment was 16; the registry record states that all participants completed treatment and were included in the analysis population. The listed dose was 5 capsules orally with meals up to 3 times daily for 4 consecutive days.

The primary outcome was change in 24-hour urinary oxalate excretion, defined as baseline average on Days 2 and 3 minus the treatment mean on Days 5, 6, and 7. The observed primary and secondary outcome results are not reported in the registry record. Serious adverse events affected 0 of 16 participants; events in the other-adverse-event category affected 9 of 16. A death count is not reported.