Re-exposure Study of Pegloticase Intravenous (i.v.) in Symptomatic Gout Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Re-exposure Study of Pegloticase Intravenous (i.v.) in Symptomatic Gout Patients (NCT00675103), a non-randomized phase 3 study. The primary outcome is Adverse Event Profile.

2. Clinical Question

The central question is descriptive and safety-focused: what did the registry record report among participants who received pegloticase again after a period without exposure? The record describes a 24-week regimen and a population whose prior pegloticase exposure was at least one year before study entry. It does not describe a comparison with participants receiving another treatment or no treatment.

The primary outcome is the adverse-event profile, expressed as the number of participants reporting events. The registry record lists 7 participants as enrolled. Its posted adverse-event summary lists 7 participants with other adverse events among 7 at risk, and 2 participants with serious adverse events; the number at risk for serious events is not reported in the registry record. It also lists cellulitis and hyperglycaemia among the leading serious adverse-event terms, each shown as 14.3%.

The study also lists mean plasma uric acid as a secondary outcome, but a result for that outcome is not reported in the registry record. The available record therefore addresses the safety question only incompletely and does not establish how re-exposure compares with an alternative. The small enrolled group and absence of a control group are important when interpreting the descriptive counts.

3. Trial Design

This was a phase 3, multicenter, open-label, non-randomized, single-group study. It enrolled 7 participants and evaluated re-exposure to pegloticase i.v. In symptomatic gout patients who had taken part in earlier pegloticase studies. The study description states that the last exposure to pegloticase was at least one year before study entry. The record describes the study as limited to four centers in the US.

The intervention was pegloticase 8 mg i.v.; the adverse-event group is labelled “Pegloticase 8 mg Every 2 Wks.” The official study title describes a 24-week regimen. There was no randomized allocation, masking, or separate control arm. As a result, the design is suited to describing events observed during re-exposure in this group, but it does not provide a direct comparison against another treatment or against no re-exposure.

The primary outcome was the adverse-event profile, measured as the number of participants reporting events over a 6-month timeframe. Mean plasma uric acid was listed as a secondary outcome. Although the record lists 2 outcome measures, a result for mean plasma uric acid is not reported in the registry record. The posted record lists no analyses.

The study is marked completed. Its enrollment is the number listed for the study, but further detail about the analysis population, participant flow, or the number contributing data to each outcome is not reported in the registry record. The protocol’s sample-size justification, statistical analysis plan, interim analyses, and methods for handling missing data are also not reported in the registry record. Those omissions limit how far the design and results can be reconstructed from the registry entry alone.

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.

Overall Study

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Adverse Event Profile, measured over 6 months.

The primary endpoint is an adverse-event profile, expressed as the number of participants reporting events during the stated 6-month timeframe. This is a participant-level measure: it counts people who report events, rather than the total number of event occurrences. The distinction matters because one participant may experience more than one event, while the participant count records whether people were affected.

In general, participant counts are a straightforward way to summarize safety observations in a clinical study. They can show whether events were reported in the study group and, when an at-risk denominator is available, how those observations relate to the number of participants under observation. They do not by themselves describe event severity, duration, recurrence, timing, or attribution to treatment. Those details require additional definitions and results.

The registry record lists 7 participants with other adverse events among 7 at risk. It lists 2 participants with serious adverse events, but the number at risk for serious events is not reported in the registry record. Cellulitis and hyperglycaemia are listed among the leading serious adverse-event terms, each shown as 14.3%. The death count is not reported in the registry record.

The registry record does not give a fuller endpoint definition, such as rules for coding events or the precise safety population. It also does not provide event-level details or a statistical comparison. Thus, these counts summarize the reported safety information but do not quantify comparative risk or establish whether an event was caused by pegloticase.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The posted results are counts of participants reporting events, rather than a treatment-effect estimate from a comparison between groups. The study has one treatment group and no randomized allocation or masking. This makes the distinction between descriptive summaries and comparative inference especially important.

What does a participant count represent?

In general, a count of participants with an event records how many people met the event definition during the observation period. It is not the same as a count of all event occurrences. If a participant experiences multiple events, a participant-level count can still include that person only once for the relevant summary. The registry record describes its primary outcome as the number of participants reporting events, but a more detailed event definition is not reported in the registry record.

A count is easiest to interpret alongside the number of participants at risk for that outcome. For other adverse events, the record lists 7 participants affected among 7 at risk. For serious adverse events, it lists 2 participants affected, but the number at risk is not reported in the registry record. Without that denominator, the serious-event count cannot be turned into a study-group proportion from the registry information alone. The entry reports cellulitis and hyperglycaemia as leading serious-event terms, each shown as 14.3%, but does not give the supporting details needed to reconstruct those percentages.

Why does the design affect interpretation?

In general, randomization helps create comparable groups, while a concurrent control provides a reference for interpreting outcomes. Neither is present: the study is non-randomized and single-group. The observed counts can describe what was recorded during re-exposure, but there is no within-trial estimate of how those counts differ from what would have occurred under another treatment or without re-exposure.

Open-label means that treatment assignment was not masked. In general, knowledge of treatment can affect reporting or assessment, depending on the outcome and how it is collected. The registry record does not report how adverse events were elicited, coded, reviewed, or attributed. It would therefore be inappropriate to assume either that reporting was affected or that it was unaffected.

What can uncertainty estimates add?

In general, a confidence interval describes the range of values compatible with the data and the statistical method used, while reflecting sampling uncertainty. For a participant-level event proportion, an interval can help show how imprecise an estimate may be, particularly when the study group is small. An interval cannot remove bias from a non-comparative design, repair a missing denominator, or establish causation. No confidence interval for the listed adverse-event counts is reported in the registry record.

Likewise, a statistical test would need to be interpreted in relation to a specific hypothesis and analysis plan. The registry entry lists no analyses. The protocol’s planned inferential methods, choice of tests, handling of repeated events, and any adjustment for baseline factors are not reported in the registry record. No unreported analysis should be inferred from the descriptive counts.

How should the planning calculations be read?

In general, sample-size planning asks how many participants may be needed to detect a specified effect under stated assumptions. The planning illustrations on this page are based on the observed effect, use 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. These are planning assumptions, not evidence that this study was designed with those assumptions. The record does not report the trial’s own sample-size justification.

Such illustrations are not observed power. They do not show that the completed study had a particular probability of finding an effect, and they cannot replace an analysis of the actual study data. They also cannot create a valid comparison for a study that enrolled one group. The design assumptions in a hypothetical two-arm planning exercise differ from the actual single-group design described in the registry record.

In general, variability and dispersion matter when planning or analyzing outcomes because they affect how much information the data contain. For participant counts, the binary status of whether a participant experienced an event is central; for event counts or rates, repeated events and over-dispersion may require different methods. The registry record does not provide the event-level information or analysis plan needed to determine which methods, beyond the stated participant counts, were used. A normal approximation is an assumption of the planning illustrations, not a description of a reported analysis for this trial.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 2 outcome measures: the primary adverse-event profile and secondary mean plasma uric acid. It does not report the result for mean plasma uric acid, and it lists no analyses. The statistical plan for deciding which outcomes or comparisons would be emphasized is not reported in the registry record. Multiplicity procedures, if any, are also not reported.

In general, evaluating multiple outcomes can increase the chance of a chance finding when many statistical tests are conducted. Methods to address this may be prespecified, but no such method can be inferred. Because the posted record gives no inferential analysis, there is no reported set of tests from which to assess whether multiplicity adjustments were used or needed.

Missing-data methods and analysis populations are not reported in the registry record. The record lists 7 enrolled participants and gives an at-risk denominator for other adverse events, but it does not explain participant flow, whether all enrolled participants contributed to every outcome, or how unavailable observations were handled. For serious adverse events, the at-risk denominator is not reported. The record also does not describe exclusions, withdrawal handling, or any rules for evaluating participants with incomplete follow-up.

In general, missing information can affect both the denominator and the interpretation of observed event counts. A complete-case summary, an analysis using all enrolled participants, and a summary using a defined safety population may not answer identical questions. The registry entry does not identify which approach was used. These omissions limit assessment of outcome completeness and prevent reconstruction of the statistical handling of missing observations.

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

The results show that the registry record lists adverse events among participants who received pegloticase again in this single-group study. It lists 7 participants with other adverse events among 7 at risk and 2 participants with serious adverse events, without reporting the serious-event denominator. Cellulitis and hyperglycaemia appear among the leading serious-event terms, each shown as 14.3%.

These summaries do not establish that pegloticase caused any reported event. The study did not include a control group, and the registry record does not provide details about event attribution or an analysis comparing outcomes under different conditions. Nor do the counts establish how the events compare with those in other populations or settings.

The results also do not answer the listed secondary question about mean plasma uric acid, because its result is not reported in the registry record. The missing serious-event denominator, unreported death count, and absence of a listed analysis further limit the conclusions that can be drawn. An unreported value should not be treated as a zero value or as proof that an outcome did not occur.

In general, a small descriptive study can help document what was observed in the group enrolled, but it offers limited precision and cannot provide a controlled estimate of treatment effect. The planning calculations on this page, if consulted, are illustrations under stated assumptions rather than evidence of observed power or the study’s original design rationale. The sound interpretation is therefore narrow: these are the adverse-event observations recorded for the study group, with substantial limits on comparative and inferential conclusions.

12. Why This Trial Matters Statistically

This study is statistically notable because it asks a re-exposure question in a single group and reports participant-level safety counts. Those features make clarity about denominators, event definitions, and comparison groups essential. The record reports an at-risk denominator for other adverse events but not for serious adverse events, so even basic interpretation is constrained by what is available for each outcome.

The design also illustrates the difference between documenting events and estimating a treatment effect. A single-group study can describe observations during treatment, but it does not contain a concurrent randomized comparison that could help separate treatment-associated outcomes from other explanations. That distinction remains important even when the study is completed and its primary outcome is safety-focused.

Another statistical lesson is that outcome labels alone do not supply a full analysis plan. The registry lists an adverse-event profile and mean plasma uric acid, but the latter’s result and any analyses are not reported in the registry record. Information about missing data, analysis populations, event definitions, and multiplicity is also not reported. These details are needed to evaluate how complete and reproducible an outcome summary is.

Finally, planning calculations should not be confused with the design or evidential strength of the completed study. Planning illustrations based on an observed effect answer a hypothetical sample-size question under stated assumptions. They do not show observed power, establish that the original enrollment was adequate, or overcome the absence of a comparator. Keeping these statistical roles separate helps readers use the posted results without asking them to answer questions the design and registry record do not address.

13. 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 principal limitation is the single-group, non-randomized design. There is no control group, so the posted counts cannot estimate a comparative effect or distinguish treatment-associated events from other causes. The open-label design adds another potential source of influence on event reporting or assessment, although its effect in this study is not reported in the registry record.

The study enrolled 7 participants. This is a small group for describing uncommon events and limits the precision and breadth of the observations. The serious-adverse-event count is 2, but its at-risk denominator is not reported in the registry record. The death count is also not reported, and the underlying details for the listed serious-event terms are not given.

The registry entry does not report a detailed adverse-event definition, event collection or coding methods, severity grading beyond serious-event classification, relatedness assessment, event timing, or participant-level follow-up. It does not specify analysis populations, participant flow, or missing-data procedures. These gaps make it difficult to assess completeness or reproduce the endpoint summaries.

The record lists mean plasma uric acid as a secondary outcome but does not report its result. It lists no analyses, and the statistical analysis plan, sample-size justification, interim analyses, and multiplicity approach are not reported in the registry record. The available information therefore supports only a limited descriptive account and does not permit a complete assessment of the planned or executed statistical methods.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Re-exposure Study of Pegloticase Intravenous (i.v.) in Symptomatic Gout Patients — NCT00675103.
• Registry record last updated 2011-06-28; status last verified 2011-06.
• Results first posted 2011-06-28.
• 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.

17. Record Summary

This completed phase 3 study evaluated re-exposure to pegloticase i.v. In symptomatic gout patients who had participated in previous pegloticase studies and whose last exposure was at least one year before study entry. The registry describes a multicenter, open-label, non-randomized, single-group design at four US centers, with 7 participants enrolled. The regimen was pegloticase 8 mg i.v. every 2 weeks over 24 weeks.

The primary outcome was the number of participants reporting adverse events over 6 months. The record lists 7 participants with other adverse events among 7 at risk and 2 participants with serious adverse events; the serious-event denominator is not reported. Cellulitis and hyperglycaemia are listed among the leading serious-event terms, each at 14.3%. Mean plasma uric acid was a secondary outcome, but its result is not reported in the registry record. No analyses are listed. The single-group design and incomplete outcome details limit comparative and inferential interpretation.