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 R-(-)-Gossypol Acetic Acid in Treating Patients With Recurrent Extensive-Stage Small Cell Lung Cancer (NCT00773955), a na phase 2 study. The primary outcome is Number of Participants With Confirmed Tumor Response Defined to be Either a Complete Response (CR) or Partial Response (PR).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00773955 |
| Phase | Phase 2 |
| Condition | Extensive Stage Small Cell Lung Cancer, Recurrent Small Cell Lung Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 15 |
| Arms in the primary outcome | n/a |
| Lead sponsor | National Cancer Institute (NCI) |
| Results posted | Yes |
2. Clinical Question
Population
Patients with recurrent extensive-stage small cell lung cancer. The registry records enrollment of 15 participants. It does not report further baseline characteristics in the information available for this analysis.
Intervention
Oral R-(-)-gossypol acetic acid once daily on days 1-21, with courses repeating every 28 days in the absence of disease progression or unacceptable toxicity. Pharmacological study and laboratory biomarker analysis are also listed.
Comparator
There was no comparison group. The trial is recorded as a single-group study with allocation listed as not applicable and no masking.
Primary question
How many participants had a confirmed complete or partial tumor response during the first 6 courses of treatment? The number of confirmed responses is not reported in the registry record.
The study is identified as a phase II evaluation of R-(-)-gossypol acetic acid in recurrent extensive-stage small cell lung cancer. Its primary endpoint is a count of participants meeting the response definition, rather than a comparison of response rates between treatments. A response had to be confirmed on 2 consecutive evaluations at least 4 weeks apart. Complete response and partial response were defined using RECIST v1.0 criteria for target lesions.
Because this was a single-group study, the central descriptive question is how many participants met that prespecified response definition during the stated treatment period. The registry record does not report the response count or a response estimate, so the result cannot be described from the available record. It also cannot establish how the response experience compares with a control group. There is no randomized or concurrent control arm listed.
Enrollment was 15. The primary-endpoint description says that one patient discontinued after one cycle because of persistent grade 1 thrombocytopenia and that fourteen patients were evaluable for the primary endpoint at the interim analysis. The registry does not report the number of responses at that analysis or explain whether a later primary-endpoint analysis was conducted. These details are important when interpreting a response count: the denominator and endpoint assessment determine what a count represents, but the confirmed-response count itself is absent.
3. Trial Design
NCT00773955 is recorded as a phase II, completed, single-group trial sponsored by the National Cancer Institute. The registry lists no masking and allocation as not applicable. Enrollment was 15. The recorded start was 2008-11 and primary completion was 2009-10. The registry does not provide a control arm or a randomized treatment comparison.
Participants received oral R-(-)-gossypol once daily on days 1-21. Courses were to repeat every 28 days in the absence of disease progression or unacceptable toxicity. Pharmacological study and laboratory biomarker analysis are also listed among the interventions. The record identifies survival time, time to disease progression, and duration of response as secondary outcomes, in addition to the primary response endpoint.
The single-group structure makes the trial descriptive with respect to the treatment experience recorded among participants. It does not support a direct treatment-versus-control contrast, because no control group is described. Results from a single group may be affected by factors such as participant selection, changes in assessment over time, or the natural course of disease; the registry does not provide information to quantify or address those factors.
The registry describes the primary endpoint population as fourteen participants evaluable at the interim analysis after one participant discontinued following one cycle. It does not report whether the interim analysis was the only analysis, how the final analysis population was defined, or whether additional participants or assessments were included in a later analysis. The statistical analysis plan, sample-size justification, and any interim-analysis plan are not reported in the registry record. Therefore, the design features and analysis decisions beyond the stated single-group structure and endpoint description cannot be reconstructed from the 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.
Before assignment: One patient discontinued therapy after one cycle of treatment due to persistent grade 1 thrombocytopenia. Therefore, fourteen patients were evaluable for the primary end point at the interim analysis. All 15 patients were included in secondary endpoint analysis.
Overall Study
| Stage | Treatment (R-(-)-Gossypol) |
|---|---|
| STARTED | 15 |
| COMPLETED | 15 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: One patient discontinued therapy after one cycle of treatment due to persistent grade 1 thrombocytopenia. Therefore, fourteen patients were evaluable for the primary end point at the interim analysis.
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.
| Characteristic | Unit | Treatment (R-(-)-Gossypol) |
|---|---|---|
| Participants analysed | 15 | |
| Age, Continuous | years | 67.0 (46 to 76) |
| Sex: Female, Male: Female | Participants | 6 |
| Sex: Female, Male: Male | Participants | 9 |
| Region of Enrollment: United States | participants | 14 |
| Region of Enrollment: Australia | participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Confirmed Tumor Response Defined to be Either a Complete Response (CR) or Partial Response (PR), measured over During the first 6 courses of treatment.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with a confirmed tumor response, defined as either complete response or partial response. The assessment period was during the first 6 courses of treatment. Confirmation required the response to be recorded as the objective status on 2 consecutive evaluations at least 4 weeks apart.
For target lesions under RECIST v1.0, complete response required disappearance of all target lesions. Partial response required at least a 30% decrease from baseline in the sum of the longest diameters of target lesions. Requiring confirmation makes the endpoint less dependent on a single assessment and applies a consistent rule for classifying a response. The endpoint is a count, so its interpretation depends on both the number meeting the definition and the population assessed.
In general, a binary endpoint classifies each assessed participant as meeting or not meeting a defined event criterion. A count of participants with the event is straightforward to understand, but by itself it does not show the uncertainty around the response rate or establish a treatment effect relative to another group. For this trial, the registry describes fourteen evaluable participants at the interim analysis but does not report the confirmed-response count. The response result therefore cannot be quantified from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the study as a phase II, single-group evaluation of R-(-)-gossypol acetic acid in recurrent extensive-stage small cell lung cancer. It records enrollment of 15 and describes the primary endpoint as the number of participants with confirmed complete or partial response during the first 6 courses. The response count and any corresponding estimate are not reported in the registry record. Consequently, no numerical statement about the observed response frequency or its precision can be made from this record.
The primary-endpoint description does give information about assessment and evaluability. One patient discontinued after one cycle because of persistent grade 1 thrombocytopenia, and fourteen patients were evaluable for the primary endpoint at the interim analysis. This tells the reader that the endpoint population at that analysis was not identical to the enrollment count. It does not reveal the number of participants who responded, the response status of the participant who discontinued, or whether the analysis population changed later.
The absence of a comparison group is central to interpretation. A response count in a single group describes the observed experience under the study regimen, but it does not provide a randomized contrast with another treatment or with no treatment. Even if a response result were available, a single-group result alone would not separate a treatment-associated outcome from other explanations for the observed outcomes. No comparative effect estimate can be recovered from the design information in the record.
The record lists secondary outcomes of survival time, time to disease progression, and duration of response, but does not include their results in the registry record for this analysis. It also records zero analyses. The statistical analysis plan, handling of missing outcome assessments, and any adjustment for multiple outcomes are not reported. These omissions limit assessment of how outcomes were analyzed and how uncertainty was quantified.
Serious adverse events are recorded for four of the fifteen participants at risk in the treatment group. The registry lists five serious-event terms among the top terms, each reported as 6.7%. The entries describe safety observations, not proof that the study drug caused each event. The record does not report a death count in the adverse-event information. Other adverse-event reporting lists fifteen affected participants among fifteen at risk. The scope and attribution of those events should not be inferred beyond the registry categories.
Overall, the record provides useful information about the treatment schedule, response definition, evaluability at an interim analysis, and recorded adverse events. It does not provide the central response count, an inferential result, or a control-based estimate. The findings therefore cannot be characterized as evidence for or against treatment efficacy from the information recorded.
9. Statistical Methods Explained
The registry describes the primary outcome as a number of participants with an event: a confirmed complete or partial tumor response. That is a binary outcome at the participant level, because each assessed participant either meets the response definition or does not. The reported endpoint is the count of participants who meet it. The registry does not report the count, a response proportion, a confidence interval, or a hypothesis-test result.
What does a confidence interval mean?
In general, a confidence interval expresses uncertainty around an estimated quantity under a specified statistical procedure. For a binary response outcome, an interval around the response proportion would help show how much uncertainty remains about the underlying response frequency represented by the observed participants. A narrower interval indicates greater precision under that procedure; a wider interval indicates less precision. It does not remove limitations from the study design, including the lack of a control group. No confidence interval is reported in the registry record for the primary endpoint, so the precision of any response estimate cannot be assessed from this record.
Why does the endpoint require confirmation?
The response definition requires a response status on 2 consecutive evaluations at least 4 weeks apart. In general, confirmation rules seek to avoid classifying an outcome from a single assessment that may not persist at the next evaluation. The rule also makes the endpoint operational: it specifies which observations count as a confirmed response. It can, however, make endpoint classification depend on having the required follow-up assessments. The registry does not describe how incomplete or unavailable assessments were handled, so the effect of missing evaluations on classification is unknown.
What does the single-group structure allow?
The study is recorded as single-group, with no masking and allocation listed as not applicable. In general, a single-group study can describe outcomes observed among participants receiving the study regimen. It cannot by itself estimate a randomized difference from a comparator, because no comparator group is present. Without such a group, it is not possible to use a between-group contrast to account for other influences on observed outcomes. This limitation is about the design and remains even if an outcome count is available.
For a comparative trial, random allocation can support a comparison between groups by reducing systematic differences in expectation across treatment assignments. That general advantage does not apply as a trial feature: the registry identifies no randomized allocation and no comparator. The record therefore supports description of the treatment group, not a causal comparative estimate.
What do the planning calculations represent?
The sample-size planning illustrations are not results from participants and are not observed power. The stated assumptions for those illustrations are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. Those assumptions describe a planning exercise, not the trial's recorded single-group design. The registry does not report the trial's own sample-size justification or statistical plan. No planning estimate should be interpreted as evidence that the study achieved a particular level of power or as an observed treatment effect.
In general, a sample-size calculation asks how many participants or events would be needed for a specified design and set of assumptions. Its result depends on the assumed effect, outcome variability or event frequency, significance level, power target, allocation, and analysis method. If the assumed effect is based on an observed effect, the illustration remains conditional on that assumption; it does not independently validate the effect. The planning displays should therefore be read as hypothetical design quantities, distinct from the study's enrollment and observed outcomes.
Why does over-dispersion matter?
In general, over-dispersion occurs when observed variability is greater than a model assumes. It can make standard errors too small if the analysis does not account for the extra variability, leading to intervals that are too narrow or tests that are too confident. This concept is relevant to count or rate outcomes analyzed with models that make assumptions about variability. The primary endpoint in this study is described as a participant count for a binary response classification, and the registry does not report a model-based analysis or an over-dispersion assessment. It would therefore be inappropriate to claim that over-dispersion was present or that a particular correction was used.
The registry also does not state whether the primary endpoint was analyzed as a raw count, a proportion, or through another method. No inferential procedure, confidence-interval method, covariate adjustment, or missing-data strategy is reported. General statistical methods can explain what those choices would mean, but they cannot be attributed to this trial without a record of the methods used.
What can the reported evaluability information establish?
The endpoint description states that fourteen participants were evaluable at the interim analysis and identifies one discontinuation after one cycle because of persistent grade 1 thrombocytopenia. This documents a difference between enrollment and the stated evaluable population at that analysis. It does not tell whether the discontinued participant was excluded under a prespecified rule, whether outcome status was available, or how any later analysis treated the participant. Those details are not reported in the registry record.
In general, a complete-case analysis uses participants with the information needed for the endpoint, while other approaches may retain participants through explicit assumptions or imputation. Different approaches can produce different estimates when outcome information is incomplete. Since the registry does not describe its analysis population or missing-data methods beyond the interim evaluability statement, no particular approach can be attributed to this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures and records zero analyses. It identifies the primary response endpoint and names survival time, time to disease progression, and duration of response as secondary outcomes. The statistical analysis plan is not reported in the registry record. There is no information about a hierarchy among outcomes, prespecified testing sequence, multiplicity adjustment, or which results were intended to support formal inference.
In general, evaluating multiple outcomes can increase the chance of observing an apparently notable result by chance if many tests are conducted without an appropriate plan. Methods such as a prespecified hierarchy or adjustment can address that issue, but the record does not state that any such method was used. The existence of several listed outcomes alone is not evidence that multiple hypothesis tests were performed.
The primary-endpoint description states that one patient discontinued therapy after one cycle because of persistent grade 1 thrombocytopenia, leaving fourteen evaluable for the primary endpoint at the interim analysis. It does not describe the participant's response status or the rule used to define evaluability. Missing-data handling, treatment of participants who discontinued, and the final analysis population are not reported. The record does not say whether the interim analysis was the only analysis or whether additional assessments contributed to a later result.
In general, missing outcome information can affect an estimate when participants with unavailable assessments differ in outcome from those assessed. An analysis that excludes such participants and an analysis that makes assumptions about their outcomes answer the question in different ways. The available record is insufficient to determine which method was used or to evaluate how sensitive the response result would be to those choices. The confirmed-response count itself is also not reported.
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 |
|---|---|---|---|
| Treatment (R-(-)-Gossypol) | 4 | 15 | 26.7% |
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 |
|---|---|
| Treatment (R-(-)-Gossypol) | 15 of 15 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment (R-(-)-Gossypol) |
|---|---|---|
| Supraventricular tachycardia | Cardiac disorders | 1 of 15 |
| Ear, nose and throat examination abnormal | Gastrointestinal disorders | 1 of 15 |
| Small intestinal obstruction | Gastrointestinal disorders | 1 of 15 |
| Vomiting | Gastrointestinal disorders | 1 of 15 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 1 of 15 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment (R-(-)-Gossypol) |
|---|---|---|
| Hemoglobin decreased | Blood and lymphatic system disorders | 10 of 15 |
| Fatigue | General disorders | 9 of 15 |
| Anorexia | Metabolism and nutrition disorders | 9 of 15 |
| Constipation | Gastrointestinal disorders | 8 of 15 |
| Serum sodium decreased | Metabolism and nutrition disorders | 7 of 15 |
| Diarrhea | Gastrointestinal disorders | 5 of 15 |
| Nausea | Gastrointestinal disorders | 5 of 15 |
| Alanine aminotransferase increased | Investigations | 5 of 15 |
| Aspartate aminotransferase increased | Investigations | 5 of 15 |
| Leukocyte count decreased | Investigations | 5 of 15 |
Serious events with the highest arm-level rate: supraventricular tachycardia (6.7%), ear, nose and throat examination abnormal (6.7%), small intestinal obstruction (6.7%), vomiting (6.7%), dyspnea (6.7%).
The registry records four participants with serious adverse events among fifteen at risk in the treatment group. It lists supraventricular tachycardia, ear, nose and throat examination abnormal, small intestinal obstruction, vomiting, and dyspnea as top serious-event terms, each at 6.7%. The record does not provide further event-level context in the information available for this analysis.
The listed percentages describe registry entries; they should not be treated as evidence that R-(-)-gossypol caused the events. Serious events can occur for many reasons, and a single-group record does not establish attribution. The registry information also does not clarify from these entries whether participants experienced more than one listed event. The terms are therefore best read as reported safety categories, not as mutually exclusive participant groups.
The other adverse-event category records fifteen participants affected among fifteen at risk. This is a separate reporting category from the serious-event information. The record does not provide the complete event details or a comparator against which to judge rates. A null death field means a death count is not reported in the registry record; it should not be interpreted as confirmation that no deaths occurred.
Safety figures describe what was recorded during the trial. They do not by themselves establish causality, comparative safety, or the likelihood of an event outside the study. The registry does not report a control group or further attribution methods.
12. What the Result Does, and Does Not, Mean
The registry record establishes that NCT00773955 was a completed phase II, single-group study of R-(-)-gossypol acetic acid in recurrent extensive-stage small cell lung cancer. It records enrollment of 15 and describes a confirmed response endpoint during the first 6 courses of treatment. It also documents that one participant discontinued after one cycle because of persistent grade 1 thrombocytopenia and that fourteen participants were evaluable for the primary endpoint at the interim analysis.
The key response result is absent: the registry record does not report how many participants had a confirmed complete or partial response. Without that count or a corresponding estimate, the response frequency and its precision cannot be described. The absence of a reported result is not evidence that there were no responses; it means that the result cannot be recovered from the available registry information.
The study design also sets a limit on what any response count could mean. A single-group result would describe outcomes observed among participants in the study, but there is no control group for a direct comparison. It would not establish how outcomes would have differed under another treatment or without the study regimen. The record does not support a comparative causal conclusion.
The record lists secondary outcomes and adverse-event information, but does not report secondary outcome results in the registry record. Serious adverse-event categories and percentages are recorded, but these observations do not establish that treatment caused the events. Likewise, planning calculations are hypothetical illustrations, not observed power and not evidence of the trial's outcome.
The defensible interpretation is therefore limited to the trial structure, stated endpoint definition, interim evaluability, and recorded safety entries. Claims about response magnitude, uncertainty, comparative benefit, or treatment-related harm would require information that is not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates why statistical interpretation depends on more than the name of an endpoint. The response outcome has a clear operational definition: complete or partial response under RECIST v1.0, confirmed on 2 consecutive evaluations at least 4 weeks apart. Such rules specify what counts as an event and make the target of measurement more reproducible. The record also notes that fourteen participants were evaluable at the interim analysis, making the analysis population relevant to interpreting any response count.
At the same time, the registry does not report the confirmed-response count or its uncertainty. The distinction between defining an outcome and reporting its observed result is fundamental: a precise endpoint definition cannot substitute for the result itself. Without the count, estimate, or interval, the magnitude and precision of the response experience cannot be assessed from the registry record.
The single-group design is another important statistical feature. It allows a description of outcomes within the treatment group, but it does not provide the comparative information needed to estimate a treatment contrast. A numerical outcome in one group is not equivalent to a causal comparison. This matters whenever readers encounter a response endpoint without a concurrent control.
Finally, the registry demonstrates the importance of transparent reporting of analysis choices. It does not report the statistical plan, missing-data handling, multiplicity approach, or details of analyses. These omissions prevent assessment of how inferential claims were planned and how incomplete assessments may have been treated. The record is informative about design and measurement, while leaving the primary numerical result and important analysis details unavailable.
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 main limitation for interpreting the primary outcome is that the confirmed-response count is not reported in the registry record. No response estimate, confidence interval, or test result is available in the registry record for this analysis. Consequently, the magnitude and precision of the primary result cannot be evaluated.
The trial is single-group, with no comparator arm and no masking. The absence of a control group prevents direct comparative estimation. The registry does not report a randomized allocation procedure, a comparator treatment, or methods that would support a controlled contrast. This is a design limitation, not something that can be remedied by calculating a response proportion for the treatment group.
The primary-endpoint description identifies fourteen evaluable participants at the interim analysis after one participant discontinued following one cycle because of persistent grade 1 thrombocytopenia. The reason for discontinuation is specified, but the participant's response status and the analysis rule for evaluability are not. The final analysis population and handling of missing assessments are not reported. The record also does not state whether the interim analysis was the only analysis.
The registry lists secondary outcomes but does not report their results in the registry record for this analysis. The statistical analysis plan, multiplicity approach, sample-size justification, and inferential methods are not reported. Thus, it is not possible to assess whether outcome analyses followed a prespecified plan or how uncertainty was calculated.
Safety interpretation is also limited by the single-group design and sparse event detail. Serious-event terms and percentages are recorded, but the record does not establish causation or provide a comparator for contextualizing the entries. The death count is not reported in the registry record. These limitations restrict conclusions to what the registry explicitly documents.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: R-(-)-Gossypol Acetic Acid in Treating Patients With Recurrent Extensive-Stage Small Cell Lung Cancer — NCT00773955.
- Registry record last updated 2014-05-12; status last verified 2011-10.
- Results first posted 2013-03-21.
- 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
NCT00773955 is a completed phase II, single-group study sponsored by the National Cancer Institute. It enrolled 15 participants with recurrent extensive-stage small cell lung cancer. The recorded start was 2008-11 and primary completion was 2009-10. Masking was listed as none, and allocation as not applicable.
The intervention was oral R-(-)-gossypol acetic acid once daily on days 1-21, with courses repeating every 28 days in the absence of progression or unacceptable toxicity. The primary endpoint counted confirmed complete or partial responses during the first 6 courses. The response count is not reported in the registry record. One participant discontinued after one cycle because of persistent grade 1 thrombocytopenia; fourteen were evaluable at the interim analysis.
Secondary outcomes included survival time, time to disease progression, and duration of response. Serious adverse events were recorded for four participants among fifteen at risk, with five listed serious-event terms each reported at 6.7%. The record does not provide a control comparison or the statistical analysis plan.