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 Tretinoin Plus Interferon Alfa in Treating Patients With Metastatic Kidney Cancer (NCT00003656), a na phase 2 study. The primary outcome is Best Response as Measured by CT, Bone Scans, and Clinical Progression.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00003656 |
| Phase | Phase 2 |
| Condition | Kidney Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 26 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Weill Medical College of Cornell University |
| Results posted | Yes |
2. Clinical Question
Population
Patients with advanced renal cell carcinoma, described in the study summary as metastatic kidney cancer. The registry lists Kidney Cancer as the condition and records enrollment of 26 participants.
Intervention
Weekly ATRA-IV, described in the arm record alongside recombinant interferon alfa. The listed interventions are tretinoin liposome and recombinant interferon alfa.
Comparator
There is no separate comparator group recorded. The study is identified as single-group, with allocation listed as NA and masking listed as none.
Primary question
The primary endpoint is best response assessed by CT, bone scans, and clinical progression after 8 weeks. The registry describes it as a count of participants, but does not report the count in the posted results.
The clinical question is whether the combination was followed by a best response in patients with advanced renal cell carcinoma during the stated assessment period. As a single-group Phase II trial, the record can describe outcomes among participants receiving the combination, but it does not provide a concurrent untreated group or an alternative-treatment group for comparison. It therefore cannot, by itself, distinguish an effect of the combination from changes that could occur for other reasons.
The study summary gives a rationale for testing tretinoin and interferon alfa and states that the purpose was to study the effectiveness of liposomal tretinoin plus interferon alfa. That rationale is not itself evidence of an outcome. The primary result is not reported as a numerical participant count in the registry record; the record says that data are available only as a combined Arm/Group based on a publication and that no additional study data were available despite efforts to locate them. The clinical question can be identified, but the posted record does not allow the primary response outcome to be quantified or its precision to be assessed.
3. Trial Design
This is a Phase II study recorded as completed. Its model is single-group, allocation is listed as NA, and masking is listed as none. The registry records enrollment of 26 and identifies Weill Medical College of Cornell University as the sponsor. The start date is 1999-01 and primary completion is recorded as 2008-05.
The listed treatment is weekly ATRA-IV with recombinant interferon alfa. The intervention list identifies tretinoin liposome and recombinant interferon alfa. There is one arm description, “All subjects,” and no separate comparator is described. The study summary characterizes the population as patients with metastatic kidney cancer; the condition is listed as Kidney Cancer.
Because the design is single-group, the study’s primary response measure is an outcome observed within the treated group rather than a contrast between randomized groups. The record explicitly cautions that this is not a randomized comparison and that arms are not a like-for-like control comparison. There is no basis in the registry record for treating the listed Phase 1 Group and Phase 2 Group in the safety information as comparable treatment arms: they appear as safety groups, not as a randomized control comparison.
The primary endpoint is best response assessed by CT, bone scans, and clinical progression after 8 weeks, expressed as a count of participants. Other recorded outcomes concern retinoic acid receptor expression and duration of response, described as progression-free survival. The registry lists four outcome measures, but no analyses are recorded. The record does not report the protocol details, treatment adherence, or a statistical analysis plan, so the design features beyond those explicitly listed cannot be established from 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.
Overall Study
| Stage | Phase 1 Group | Phase 2 Group |
|---|---|---|
| STARTED | 12 | 14 |
| COMPLETED | 12 | 13 |
| NOT COMPLETED | 0 | 1 |
Reasons for not completing this period:
| Reason | Phase 1 Group | Phase 2 Group |
|---|---|---|
| Adverse Event | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Data are only available as a combined Arm/Group based on information contained in the study publication. No additional study data is available despite exhausting all efforts to locate the data.
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: Data are only available as a combined Arm/Group based on information contained in the study publication. No additional study data is available despite exhausting all efforts to locate the data.
| Characteristic | Unit | Phase 1 Group | Phase 2 Group | Total |
|---|---|---|---|---|
| Participants analysed | 12 | 14 | 26 | |
| Age, Customized: Median age | years | 66.5 (42 to 79) | 61.1 (47 to 75) | 63.6 (42 to 79) |
| Sex: Female, Male: Female | Participants | 5 | 4 | 9 |
| Sex: Female, Male: Male | Participants | 7 | 10 | 17 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Prior nephrectomy: Yes prior nephrectomy | Participants | 12 | 12 | 24 |
| Prior nephrectomy: No prior nephrectomy | Participants | 0 | 2 | 2 |
| Histology: Clear cell | Participants | 7 | 9 | 16 |
| Histology: Clear cell with sarcomatoid features | Participants | 1 | 4 | 5 |
| Histology: Papillary | Participants | 1 | 0 | 1 |
| Histology: Xp11 | Participants | 0 | 1 | 1 |
| Histology: Unclassified | Participants | 3 | 0 | 3 |
| Number of patients with metastases at the time of diagnosis | Participants | 6 | 8 | 14 |
6. Primary Endpoint
The registry lists the primary outcome as Best Response as Measured by CT, Bone Scans, and Clinical Progression, measured over After 8 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is best response, measured using CT, bone scans, and clinical progression after 8 weeks. Its unit is participants, and the outcome is described as a count of participants. This type of endpoint is intended to classify or count participants according to whether a response meeting the study’s assessment criteria was observed. Imaging and clinical assessment provide the stated basis for that classification.
Best response is used in studies of cancer treatments to describe tumor response over a specified assessment period. It addresses a different question from how long a response lasts: a participant may meet a response criterion at an assessment, while duration of response concerns time until a later event. The registry separately lists duration of response, described as progression-free survival, with progression assessed by CT, bone scans, and clinical progression. That secondary outcome is not interchangeable with best response.
The registry record does not give the primary endpoint’s participant count. Its population note says that data are available only as a combined Arm/Group based on information in a study publication, and that no additional study data are available despite efforts to locate them. Without the reported count, the posted record cannot show how many participants met the response criteria, nor can it provide an estimate of uncertainty around that result. The record also does not include detailed response definitions beyond the listed assessment methods and timeframe.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically relevant question and the endpoint used to address it, but it does not provide the primary response count. It records best response after 8 weeks as a participant count and says the data are available only as a combined Arm/Group based on a study publication. The actual numerical result is not reported in the registry record. Consequently, readers cannot use the posted primary result to determine the observed response frequency or how precisely it was estimated.
That absence matters for statistical interpretation. A count on its own would describe the observed outcome; an interval around an estimate would help convey uncertainty. Neither a primary count nor an interval is reported in the registry record. No primary statistical analysis is listed, and the record gives no inferential test or model result for this endpoint. The absence of a reported analysis does not establish that no analysis was performed elsewhere; it means the registry record does not document one.
The single-group design also limits what any within-group result could establish. Without a concurrent comparator, an outcome among participants receiving treatment cannot be interpreted as a treatment-versus-control effect. The record lists no randomized allocation and specifically notes that it is not a randomized comparison. Even if a response count were available, it would describe outcomes in the study group rather than isolate the contribution of either treatment component.
Safety information is reported separately for a Phase 1 Group and a Phase 2 Group. The serious adverse event figures are 1 among 12 at risk in the Phase 1 Group and 0 among 14 at risk in the Phase 2 Group; deaths are recorded as 0 in each group. These are descriptive registry entries. They do not establish a comparative safety effect, particularly because the study is not recorded as a randomized comparison and the safety groups are not described as like-for-like controls. Leukopenia is listed among the top serious terms at 8.3%, but the record does not state which safety group that percentage refers to.
Overall, the posted information supports a description of the study design, its intended response endpoint, and selected safety counts. It does not support a numerical interpretation of the primary response outcome, an estimate of comparative treatment effect, or a conclusion about precision. Results from a single-group study and incomplete outcome reporting should be kept distinct from evidence of a causal treatment effect.
9. Statistical Methods Explained
Statistical methods help define what a trial can estimate and how uncertain that estimate is. In this study, the key design fact is that the trial is recorded as single-group, with allocation listed as NA and masking listed as none. The endpoint is a participant count for best response after 8 weeks. These registry entries determine the kinds of interpretations that are available from the registry record.
What does a single-group design estimate?
In general, a single-group study describes outcomes among the participants who received the study treatment. It does not directly estimate a difference between that treatment and a separate control treatment, because no concurrent comparator is recorded. In a randomized comparison, random allocation can support a more direct estimate of a treatment contrast, subject to the design and analysis assumptions. Here, the registry explicitly notes that this is not a randomized comparison and that arms are not a like-for-like control comparison.
That distinction is important even when an outcome seems clear. A count of participants meeting a response definition can describe what was observed in the study group. It cannot, on its own, show what would have occurred in a comparable group without the treatment or under another treatment. Observed outcomes may reflect more than the treatment being studied. The record does not report a control group or an adjusted comparison that would address this issue.
How should a participant count be interpreted?
For a binary outcome, each participant is classified according to whether an event or response occurred. A count reports the number classified in the relevant category; the proportion would also depend on the denominator assessed. The primary endpoint is described as a count of participants, but its numerical count is not reported in the registry record. It would therefore be inappropriate to infer a response rate or uncertainty measure from the enrollment figure alone. Enrollment and the number with an evaluable endpoint are not necessarily interchangeable, and the record does not give the primary endpoint denominator.
In general, a confidence interval gives a range of values compatible with the observed data under a specified method and assumptions. It communicates precision, rather than guaranteeing that the true value lies within the interval. No confidence interval for the primary endpoint is reported in the registry record. Without the count and an analysis denominator, the precision of the primary result cannot be evaluated from the posted information.
What can the safety counts show?
The safety entries report counts for serious adverse events, other adverse events, and deaths within the named Phase 1 Group and Phase 2 Group. Such counts are descriptive. They can indicate what was recorded in each group, but they do not by themselves establish that a treatment caused an event or that one group had greater risk than another. Comparisons require an appropriate design, clear definitions, exposure and follow-up information, and an analysis suited to the data. Those details are not reported in the registry record.
General statistical practice also distinguishes event counts from event rates. A count alone does not account for differences in the time participants were observed or the duration they received treatment. The registry entries include at-risk counts, but do not report person-time or a rate analysis. The listed 8.3% for leukopenia is a registry percentage among the top serious terms; the record does not identify its group attribution or provide further detail on its calculation.
Why does missing outcome information matter?
Missing or unavailable endpoint data can affect both the estimated outcome and its precision. If participants with unavailable assessments differ systematically from those with observed assessments, an analysis restricted to available outcomes may not represent the full study group. In general, statisticians examine how much outcome information is missing, why it is missing, and how conclusions change under reasonable assumptions. The registry record says that primary data are available only as a combined Arm/Group based on a publication and that no additional study data are available despite efforts to locate them. It does not provide the primary count, the denominator assessed, or a missing-data analysis.
Analysis populations also matter. A trial may define which participants are included in an outcome analysis, such as all enrolled participants or only those with an evaluable assessment. These definitions affect the denominator and interpretation. The primary population definition and analysis population are not reported in the registry record. No analyses are listed, so it is not possible to determine which population, if any, underlies a numerical primary result in the registry.
What can planning calculations tell a reader?
Sample-size calculations are planning tools: they estimate the amount of information a proposed study might need under stated assumptions. The registry’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The same record identifies the trial as single-group and not a randomized comparison. Planning illustrations based on two-arm assumptions should not be read as the design actually used or as evidence that the study had a particular level of power.
Sample-size illustrations are not observed power. Observed power is not a useful substitute for reporting an effect estimate and its uncertainty after a study. The registry record does not report a statistical plan or a sample-size justification for this study; those details are not reported in the registry record. The planning assumptions do not fill the gap in the primary outcome reporting and do not allow a response estimate to be reconstructed.
Finally, multiple outcomes can raise multiplicity concerns. If many outcomes or analyses are tested, the chance of at least one apparently notable result can increase. General approaches include prespecifying a primary outcome, controlling error across tests, or interpreting secondary analyses as exploratory. The registry lists four outcome measures but does not report an analysis plan or multiplicity adjustment. No conclusions about the handling of multiple outcomes can be drawn from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, including best response, retinoic acid receptor expression, and duration of response. Having multiple outcomes raises a general statistical issue: when many outcomes are examined, the chance of finding an apparently notable result by chance can increase. Trials may address this by identifying a primary endpoint in advance, specifying a testing sequence, adjusting for multiple comparisons, or treating additional outcomes as exploratory. The registry record does not report a multiplicity strategy or a detailed statistical analysis plan.
The record identifies best response as the primary endpoint, but it does not report a numerical result for that endpoint. The outcome population note says data are available only as a combined Arm/Group based on information in a study publication and that no additional study data are available despite efforts to locate them. The primary count, the number assessed, and a missing-data analysis are not reported in the registry record. Thus, the extent and handling of unavailable outcome data cannot be assessed.
Analysis populations are also not described. In general, conclusions can depend on whether the analysis includes all enrolled participants, only participants who received treatment, or only those with an evaluable endpoint. The registry does not state which population was used for the primary response analysis. It lists no analyses, so the analysis population and any treatment of incomplete assessments are not reported in the registry record. These gaps limit reproducibility and make it difficult to judge how the recorded endpoint would relate to all enrolled participants.
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 |
|---|---|---|---|
| Phase 1 Group | 1 | 12 | 8.3% |
| Phase 2 Group | 0 | 14 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Phase 1 Group | 0 of 12 |
| Phase 2 Group | 0 of 14 |
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 |
|---|---|
| Phase 1 Group | 12 of 12 |
| Phase 2 Group | 14 of 14 |
Most frequent serious adverse event terms
| Event term | Organ system | Phase 1 Group | Phase 2 Group |
|---|---|---|---|
| Leukopenia | Investigations | 1 of 12 | 0 of 14 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Phase 1 Group | Phase 2 Group |
|---|---|---|---|
| Neurologic - Grade 1 | Nervous system disorders | 8 of 12 | 9 of 14 |
| Xeroderma - Grade 1 | Skin and subcutaneous tissue disorders | 11 of 12 | 5 of 14 |
| Fatigue - Grade 1 | General disorders | 7 of 12 | 8 of 14 |
| Anorexia - Grade 1 | Metabolism and nutrition disorders | 9 of 12 | 6 of 14 |
| Altered Mood - Grade 1 | Psychiatric disorders | 8 of 12 | 4 of 14 |
| Fatigue - Grade 2 | General disorders | 5 of 12 | 4 of 14 |
| Constipation - Grade 1 | Gastrointestinal disorders | 5 of 12 | 4 of 14 |
| Diarrhea - Grade 1 | Gastrointestinal disorders | 5 of 12 | 4 of 14 |
| Fever - Grade 1 | Immune system disorders | 4 of 12 | 5 of 14 |
| Nausea/Vomiting - Grade 1 | Gastrointestinal disorders | 2 of 12 | 6 of 14 |
Serious events with the highest arm-level rate: leukopenia (8.3%).
The registry reports safety figures for a Phase 1 Group and a Phase 2 Group. In the Phase 1 Group, 1 serious adverse event is recorded among 12 at risk, and 12 other adverse events are recorded among 12 at risk. In the Phase 2 Group, no serious adverse events are recorded among 14 at risk, and 14 other adverse events are recorded among 14 at risk. Deaths are recorded as 0 in each group. These are the registry counts and should be read as descriptive entries, not as estimates of comparative risk.
Leukopenia is listed among the top serious terms at 8.3%. The registry record does not state which group this percentage refers to or provide enough detail to independently interpret its denominator. It should not be assigned to a particular group based on the other safety counts.
The groups are not described as randomized treatment and control arms, and the study is identified as single-group. The safety entries therefore do not establish a causal comparison between treatments. The registry record does not provide additional information on exposure duration, event definitions, event timing, or a statistical safety analysis. Counts can help describe what the record contains, but should not be treated as a complete account of risk or as proof that an event was caused by treatment.
12. What the Result Does, and Does Not, Mean
The record establishes that a Phase II, single-group study evaluated weekly ATRA-IV with recombinant interferon alfa in patients described as having advanced renal cell carcinoma or metastatic kidney cancer. It specifies best response after 8 weeks as the primary endpoint, assessed using CT, bone scans, and clinical progression. These details define what the study set out to describe.
The posted record does not give the primary response count. Although it notes that primary data are available only as a combined Arm/Group based on a study publication, the numerical count is not reported in the registry record. No confidence interval or primary analysis result is listed. Accordingly, the posted results do not allow a reader to quantify the observed response outcome or determine its statistical precision.
Even if a within-group response result were available, the single-group design would not provide a randomized comparison with another treatment or a control. Such a result could describe outcomes in the study participants, but would not by itself show how outcomes would differ under another treatment. The record explicitly states that this is not a randomized comparison and that arms are not a like-for-like control comparison.
The safety entries provide counts for the named Phase 1 Group and Phase 2 Group, including serious events, other events, and deaths. They are descriptive and do not establish comparative safety. The leukopenia entry is reported as 8.3%, but its group attribution is not stated in the registry record.
These distinctions are important: a study’s rationale, design, and endpoint are not results, and results are not automatically evidence of causation. The record supports a description of the study and selected safety data. It does not support a numerical conclusion about the primary response outcome, a treatment-versus-control effect, or a precise estimate of benefit or harm.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of the gap between a clearly described research question and an outcome that can be interpreted from the registry record. The study identifies a Phase II, single-group treatment, a target population, and a primary response endpoint with a stated assessment timeframe. Yet the primary participant count is not reported in the posted results. Without that result, the central response question cannot be quantified from the record.
The design also demonstrates why a within-group outcome and a comparative treatment effect are different quantities. A single-group study can document what happened among participants who received the intervention, but does not establish what would have happened under a comparator. The registry itself notes the absence of a randomized comparison and cautions against treating arms as like-for-like controls. This limitation remains even if an outcome count is available from another source.
Reporting completeness is a separate statistical concern. An endpoint definition is more useful when paired with its observed count, denominator, uncertainty, analysis population, and analysis method. Those primary-result details are not reported in the registry record. The record also lists four outcome measures without describing how multiplicity was addressed. These omissions make it difficult to assess precision, reproduce an analysis, or understand how secondary outcomes relate to the primary question.
The safety entries illustrate another interpretive point: counts and percentages require context. The group-specific counts can be described, but they do not establish comparative risk in a single-group study, and the leukopenia percentage is not assigned to a group. Keeping these limits explicit prevents descriptive information from being mistaken for a causal or fully quantified treatment effect.
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 most direct limitation is incomplete primary outcome reporting in the registry. Best response after 8 weeks is specified as a participant count, but the count itself is not reported in the registry record. The record says the data are available only as a combined Arm/Group based on a study publication and that no additional study data are available despite efforts to locate them. A denominator for the primary endpoint, an uncertainty interval, and a primary analysis are also not reported.
The study is single-group, with allocation listed as NA and masking listed as none. There is no concurrent comparator in the registry record, and the record cautions that this is not a randomized comparison. Thus, the design cannot support a direct randomized treatment contrast. The safety groups are not described as like-for-like treatment and control groups.
The registry lists four outcome measures but does not report a detailed statistical analysis plan or a multiplicity approach. The analysis population, handling of missing assessments, and endpoint-specific response criteria are not reported in the registry record. These missing details restrict interpretation and reproducibility.
For safety, the registry reports group-level counts and lists leukopenia at 8.3% among the top serious terms, but it does not state the group attribution for that percentage. Additional context such as event timing, exposure duration, and the methods used to collect or classify events is not reported in the registry record. The posted safety data therefore provide only a limited descriptive account.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Tretinoin Plus Interferon Alfa in Treating Patients With Metastatic Kidney Cancer — NCT00003656.
- Registry record last updated 2022-03-18; status last verified 2022-03.
- Results first posted 2022-03-18.
- 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
The registry record describes a completed Phase II, single-group study of weekly ATRA-IV with recombinant interferon alfa in patients with advanced renal cell carcinoma. Enrollment is recorded as 26. Best response after 8 weeks, assessed by CT, bone scans, and clinical progression, is the primary endpoint.
The primary response count is not reported in the registry record. The record lists four outcome measures and no analyses. Safety information includes serious and other adverse event counts for a Phase 1 Group and a Phase 2 Group, with deaths recorded as 0 in each group. Leukopenia is listed among the top serious terms at 8.3%, without a stated group attribution.
The study is not a randomized comparison, and the registry cautions that arms are not like-for-like controls. The posted information supports a limited description of the design and safety entries, but not a quantified primary response estimate or a comparative treatment effect.