Pomalidomide for Kaposi Sarcoma in People With or Without HIV: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pomalidomide for Kaposi Sarcoma in People With or Without HIV (NCT01495598), a non-randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Grades 1-4 Adverse Events That Are Possibly, Probably, and/or Definitely Attributed to Pomalidomide.

2. Clinical Question

3. Trial Design

This was a phase I/II, sequential, non-randomized study of pomalidomide for Kaposi sarcoma. The registry lists enrollment of 28 and describes participants with and without HIV. The study was sponsored by the National Cancer Institute (NCI), began on 2012-01-10, reached primary completion on 2022-05-17, and has completed status. The registry reports no masking.

The intervention descriptions specify pomalidomide 5mg daily for 21 days of each 28-day cycle. The phase I description says up to six subjects would initially be treated. The phase II description refers to 15 HIV-positive and 10 HIV-negative participants evaluable for response. Those are descriptions of the study design and evaluability targets; the registry record does not establish that those exact subgroup counts were ultimately treated or analyzed. The brief description says participants could receive up to six cycles, with treatment potentially ending earlier if lesions completely resolved. It also mentions continuing treatment in the event of improvement after six cycles, but the registry description is truncated before the details are complete.

The sequential phase structure means the study was not designed as a randomized comparison between pomalidomide and another treatment. Phase I and phase II serve different study purposes, and differences between participants or outcomes across phases cannot by themselves establish a treatment effect. The non-randomized allocation and absence of masking also mean that outcome assessment and participant experience may be vulnerable to influences that a blinded randomized design can reduce.

The registry lists 18 outcome measures and 51 analyses. These include safety, antitumor effects, self-reported health-related quality of life, cytokine and immune-cell measures, and viral-load outcomes. The registry record does not report a full statistical analysis plan, the final analysis populations, or numerical results for those other outcomes.

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 Number of Participants With Grades 1-4 Adverse Events That Are Possibly, Probably, and/or Definitely Attributed to Pomalidomide, measured over During each cycle and 4 weeks after completing therapy, with any continuing AE's observed until resolution, approximately 124 months and 1 day..

The primary endpoint is a participant count: the number with grade 1–4 adverse events assessed as possibly, probably, and/or definitely attributed to pomalidomide. The registry says these events were assessed using CTCAE v4.0. Grade 1 is mild, grade 2 moderate, grade 3 severe, and grade 4 life-threatening. This endpoint is intended to describe the frequency of treatment-attributed adverse events across the stated severity range, rather than to measure tumor response.

A participant count is useful for communicating how many people experienced an event, but it does not by itself describe the number of events per person, their duration, or their clinical course. Nor does a total across grades show how many events occurred at each grade unless those results are separately reported. The registry describes assessment during each cycle and for four weeks after completing therapy, with any continuing adverse event observed until resolution; the stated timeframe also includes an approximate duration. The registry record does not report the endpoint’s numerical result by grade or the detailed rules used to assign attribution.

The endpoint is also distinct from the serious adverse event summary. Seriousness and severity are different classifications, and the registry’s serious-event counts do not establish that those events were judged attributable to pomalidomide. The registry record does not report a participant-level link between the primary endpoint and the serious-event summary.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Clinical trial results can be summarized with counts, proportions, effect estimates, and uncertainty intervals. Each answers a different question. A count describes how many participants experienced an event; a proportion relates that count to a defined group; an effect estimate compares outcomes between groups; and a confidence interval describes the range of values compatible with the data under the method’s assumptions. These are general statistical concepts. For this study, the registry reports safety counts and selected percentages, but the information analyzed does not include a treatment-comparison estimate or its confidence interval.

What does a participant count tell us?

The primary endpoint is a count of participants with possibly, probably, and/or definitely attributed grade 1–4 adverse events. This makes the participant, rather than each separate event, the unit of the endpoint. A participant who experiences multiple events may still contribute once to a participant count, depending on the study’s counting rules. Those detailed rules are not reported in the registry record. Counts can be straightforward to interpret, but they do not show how many events each participant experienced or how long an event lasted.

The registry also reports serious-event and other-event counts. Those summaries address whether participants were recorded as having events in those categories; they do not automatically give the same information as the primary endpoint. In particular, seriousness, severity grade, and attribution are separate concepts. CTCAE v4.0 severity grades range from mild at grade 1 to life-threatening at grade 4, as described in the registry. A serious adverse event is classified using seriousness criteria, not simply by being a high severity grade. The posted serious-event counts therefore should not be interpreted as counts of events attributed to treatment or as a grade distribution.

Why does attribution matter?

Attribution is an assessment of whether an adverse event may be related to the intervention. The primary endpoint includes events judged possibly, probably, and/or definitely attributed to pomalidomide. Such judgments are clinically informed but can involve uncertainty. In an unmasked study, participants and investigators know which intervention is being given, so expectations and knowledge of treatment may influence reporting or attribution. The registry does not report how attribution was adjudicated, whether reviewers were independent, or whether the assessment process changed over the course of the study.

Why is a randomized comparator important?

Random allocation aims to create groups that are comparable, on average, in both measured and unmeasured characteristics. A control group can help distinguish outcomes associated with treatment from outcomes that might occur without it. This study is explicitly non-randomized and has no like-for-like control comparison in the registry record. As a result, comparing participants who received pomalidomide with an external or subgroup reference would not remove possible differences in illness, care, or participant characteristics. Descriptive counts remain useful for documenting what was observed, but they cannot isolate a causal treatment effect.

The study’s sequential phase I/II model also matters. Phase I and phase II have different roles within a development program, and the phase descriptions should not be treated as arms of a randomized trial. A phase comparison can reflect differences in enrollment, eligibility, follow-up, or assessment as well as differences in treatment experience. The registry record does not report a statistical plan for comparing phases or HIV subgroups.

How should percentages and uncertainty be read?

A percentage expresses a count relative to a denominator. It is interpretable only when the denominator and counting convention are clear. The serious-event summary lists percentages for particular event terms, but the registry record does not explain the denominator and detailed convention for those terms in the information analyzed. The percentages are therefore best read as the registry’s descriptive listings, not as precise estimates of comparative risk.

In general, a confidence interval can show how uncertain an estimate is because of sampling variability. Wider intervals indicate less precision, while narrower intervals indicate greater precision under the statistical model. A confidence interval does not account automatically for every source of bias, such as non-random treatment allocation, incomplete follow-up, or unmasked assessment. The registry record does not report confidence intervals for the safety figures.

What do planning calculations mean?

Sample-size calculations are planning illustrations based on assumptions; they are not observed trial outcomes and are not observed power. General planning calculations depend on the target effect, significance level, allocation, and statistical method. The posted planning assumptions specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with target effects expressed as fractions of an observed effect. Such calculations do not turn this non-randomized study into a randomized comparison. They should not be interpreted as evidence that the trial had a particular probability of detecting an effect. The registry record does not report that these assumptions were the study’s own design assumptions or sample-size justification.

The registry lists many outcomes and analyses. When many questions are tested, the chance of at least one apparently unusual result can increase if each is assessed without adjustment. Whether and how to address this issue depends on a prespecified analysis strategy. The registry record does not report a multiplicity adjustment plan. Because numerical results for most listed outcomes are not included in the information analyzed here, no inference about statistical significance across those outcomes is possible.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 18 outcome measures and 51 analyses, spanning safety, antitumor effects, quality of life, immune and cytokine measures, and viral loads. Multiple outcomes and analyses create a multiplicity concern: when many statistical questions are examined, some findings may appear noteworthy by chance, especially if no adjustment or prioritization was planned. The registry record does not report whether a primary analysis hierarchy, multiplicity adjustment, or prespecified approach to interpreting secondary outcomes was used. Statistical significance across the listed outcomes therefore cannot be assessed from the available information.

Missing-data methods are also not reported in the registry record. The information analyzed does not specify the amount or pattern of missing outcome data, how participants who stopped treatment were handled, or whether analyses used imputation or another method. These details matter because incomplete outcome measurement can affect both the precision and interpretation of estimates.

The phase II description refers to participants evaluable for response, but the registry record does not define evaluability or report how many participants were included in each final analysis. It does not state whether the primary safety analysis included all enrolled participants, those who received treatment, or another population. Nor does it describe the handling of participants who did not complete treatment. The posted safety counts have denominators, but those alone do not establish the full analysis-population rules.

Without the statistical plan, analysis populations, and missing-data details, reported counts can still be described as registry results, but they cannot be fully audited for alignment with prespecified methods or completeness of follow-up.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death not otherwise specified (nos) (14.3%), anemia (7.1%), dyspnea (7.1%), fever (7.1%), hypotension (7.1%).

The serious adverse event summary lists 12 participants affected among 28 at risk in the pomalidomide group. The other adverse event summary lists 28 affected among 28 at risk, and the death count is 4. These summaries are descriptive. The registry does not report whether the serious events or deaths were attributed to pomalidomide, and the death count does not establish cause or timing.

The listed serious-event terms are Death Not otherwise specified (NOS) at 14.3%, and anemia, dyspnea, fever, hypotension, and platelet count decreased at 7.1% each. These percentages should be read as term-specific entries in the registry summary, not as a full account of event duration, recurrence, or severity. The registry record does not explain the denominator and counting convention for each term in the information analyzed.

Seriousness is not the same as CTCAE grade, and neither category alone establishes treatment attribution. The primary endpoint specifically concerns grade 1–4 events judged possibly, probably, and/or definitely related to pomalidomide; the serious adverse event summary does not directly report that endpoint. With no randomized control group, these safety observations also cannot quantify how event rates compare with outcomes under another treatment or no study treatment.

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

The record documents a non-randomized, open-label study of pomalidomide in people with Kaposi sarcoma, including people with and without HIV. It describes a daily 5mg regimen for 21 days of a 28-day cycle and lists safety and antitumor outcomes among the study measures. The posted safety summary reports serious adverse events for 12 participants among 28 at risk, other adverse events for 28 among 28 at risk, and 4 deaths. It also lists selected serious-event terms and their percentages.

These results do not establish that pomalidomide caused the reported serious events or deaths. The registry record does not report attribution for those summary entries, and the primary endpoint’s numerical result is not included in the information analyzed. The safety summaries also do not show how outcomes compare with a control treatment, because the study was not randomized and no like-for-like control group is reported.

The registry describes antitumor effects as secondary outcomes, but numerical response results are not reported in the registry record in the information available for this analysis. The design and enrollment description alone cannot establish whether tumor outcomes differed by HIV status, or whether any observed changes were due to pomalidomide. Phase II evaluability descriptions are not observed response results.

More generally, a descriptive result can identify what was recorded among participants in a study, while a causal conclusion requires a design and analysis that address alternative explanations. The non-randomized, unmasked design, lack of reported outcome details, and unreported analysis methods limit that distinction. The results should therefore be read as observations from this study rather than as a definitive estimate of comparative safety or efficacy.

13. Why This Trial Matters Statistically

This trial raises statistical questions common to early-phase studies: how to characterize safety, how to distinguish event seriousness from severity and attribution, and how to interpret results when treatment is not randomized. Its primary endpoint counts participants with treatment-attributed adverse events across CTCAE grades 1–4. That endpoint is relevant to safety description, but it does not replace a detailed account of event type, grade, duration, recurrence, or clinical course.

The inclusion of people with and without HIV makes subgroup reporting important. The registry describes the intended phase II response-evaluable groups, but the numerical subgroup outcomes and final analysis counts are not reported in the registry record for this analysis. This illustrates why planned group descriptions must be distinguished from observed results, and why subgroup conclusions require outcome estimates and adequate detail about who was analyzed.

The trial also demonstrates the limits of drawing comparative conclusions from a single, non-randomized treatment group. Counts and percentages can summarize observations, but they do not control for differences in underlying risk, disease status, or other care. A randomized comparator is not merely a way to produce a second set of numbers; it is a design feature that supports more credible separation of treatment effects from other influences.

Finally, the registry lists many outcomes and analyses without reporting a multiplicity plan, missing-data approach, or complete analysis-population details. These omissions make it harder to assess the robustness and precision of results. The statistical value of the record lies in identifying the design and reported safety observations while making clear what cannot be inferred from them.

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.

The registry record identifies the study as non-randomized and unmasked, with no like-for-like control comparison. This limits causal interpretation of safety or antitumor findings. The study enrolled participants with and without HIV, but the numerical outcome results by HIV status and the final subgroup analysis counts are not reported in the registry record in the information analyzed.

The primary endpoint is described, but its numerical result is not reported in the available information. The serious adverse event summary is separate from that endpoint and does not establish treatment attribution. The record does not provide detailed event-level information, a grade-by-grade account, or an explanation of the listed serious-event term denominators and counting convention. The death count is reported without a cause or attribution breakdown.

The registry lists 18 outcome measures and 51 analyses, but the statistical analysis plan, multiplicity procedures, missing-data methods, and detailed analysis populations are not reported in the registry record. The phase II description refers to evaluability for response without defining the criteria or documenting final numbers analyzed. These gaps limit assessment of completeness, precision, and adherence to planned analyses.

The registry’s brief study description is truncated, so it does not provide a complete account of treatment continuation rules. No further protocol details, sample-size justification, or interim-analysis plan are reported in the registry record. The non-randomized design and the reporting gaps should be considered alongside any numerical summaries when assessing what the study can establish.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Pomalidomide for Kaposi Sarcoma in People With or Without HIV — NCT01495598.
• Registry record last updated 2022-11-01; status last verified 2022-10.
• Results first posted 2022-11-01.
• 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.

18. Record Summary

The registry describes a completed, sequential phase I/II, non-randomized, unmasked study of pomalidomide for Kaposi sarcoma in people with or without HIV. Enrollment is listed as 28. The treatment description specifies pomalidomide 5mg daily for 21 days of a 28-day cycle. The primary endpoint counts participants with grade 1–4 adverse events assessed as possibly, probably, and/or definitely attributed to pomalidomide.

The safety summary lists 12 participants with serious adverse events among 28 at risk, 28 with other adverse events among 28 at risk, and 4 deaths. Numerical results for the primary endpoint and antitumor outcomes are not reported in the registry record in the information analyzed. With no randomized comparator, these data are descriptive and do not establish comparative effects or event attribution.