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 Phase II Study of TAS-109 to Treat Advanced Colorectal Cancer (NCT00824161), a non-randomized phase 2 study. The primary outcome is Percentage of Progression Free Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00824161 |
| Phase | Phase 2 |
| Condition | Advanced Colorectal Cancer |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 28 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Taiho Pharmaceutical Co., Ltd. |
| Results posted | Yes |
2. Clinical Question
Population
Patients with chemotherapy-refractory advanced colorectal cancer were eligible for the study. The registry lists advanced colorectal cancer as the condition and describes the study population as patients with chemotherapy-refractory disease. The record identifies an intent-to-treat population for the primary endpoint, but does not report further eligibility details or describe how that population was assembled.
Intervention
The intervention was TAS-109, given by continuous intravenous 14-day infusion. The registry describes a single study group receiving TAS-109. It does not report additional details about dose, treatment duration beyond the infusion description, or modifications to treatment.
Comparator
There was no concurrent comparator group. The study is listed as non-randomized, unmasked, and single-group. Its design therefore does not support a like-for-like comparison with another treatment or control condition. Comparisons with other studies would also be indirect and subject to differences in participants, care, and measurement.
Primary question
The primary question was the percentage of patients without progressive disease or death by three months of therapy. The endpoint description calls this percentage progression-free survival and specifies the intent-to-treat population. Although the record describes how the endpoint was defined, it does not report the observed percentage or its 95% confidence interval. The registry’s timeframe refers to time from randomization, even though the study is described as non-randomized; the applicable time origin is therefore unclear in the record.
3. Trial Design
This was a Phase II, non-randomized, single-group study of TAS-109 in patients with chemotherapy-refractory advanced colorectal cancer. The registry describes TAS-109 as a drug administered by continuous intravenous 14-day infusion. There was no masking and no concurrent control group. Enrollment was listed as 28.
The registry lists the study status as terminated, with a start date of 2009-01 and primary completion in 2009-11. It does not report why the study was terminated, so the status alone cannot establish whether termination related to recruitment, safety, efficacy, operational issues, or another cause.
The stated primary objective was to evaluate progression-free survival. Secondary objectives included antitumor activity, objective tumor response, duration of clinical benefit, overall survival, and safety. The registry lists antitumor activity and overall survival among secondary outcomes, and reports 3 outcome measures. It lists 0 analyses.
Because the design has one study group and no random allocation, it can describe outcomes among participants who received TAS-109 but cannot isolate a treatment effect from other explanations for observed outcomes. The registry record does not report a protocol-level statistical plan, a sample-size justification, interim analyses, or a reason for the single-group design. These details should not be inferred from the phase or the study status.
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: No screening period.
Overall Study
| Stage | TAS-109 |
|---|---|
| STARTED | 28 |
| COMPLETED | 26 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | TAS-109 |
|---|---|
| Withdrawal by Subject | 1 |
| Screen Failure | 1 |
Analysis population for the primary outcome, as defined in the registry: Analysis was Intent to treatment(ITT) population.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | TAS-109 |
|---|---|---|
| Participants analysed | 28 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 20 |
| Age, Categorical: >=65 years | Participants | 8 |
| Age Continuous | years | 55.8 (SD 10.19) |
| Sex: Female, Male: Female | Participants | 17 |
| Sex: Female, Male: Male | Participants | 11 |
| Region of Enrollment: United States | participants | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Progression Free Survival, measured over From date of randomization until date of the first documented progressive disease (PD) or death from any cause, whichever came first, assessed up to 3 months..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of PFS patients |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was described as the percentage of patients without progressive disease or death by 3 months of therapy. The registry defines progression-free status by the absence of progressive disease or death, whichever came first. It specifies an intent-to-treat population and a 95% confidence interval as the dispersion measure. The endpoint timeframe also describes assessment from the date of randomization through the first documented progression or death, up to 3 months.
Progression-free survival is used to capture whether a participant remains alive without documented disease progression over a defined period. In general, a time-to-event endpoint can account for both progression and death as events, rather than focusing only on tumor response at a particular assessment. A percentage at a fixed time point is a simpler summary of that status at the specified time.
The registry’s wording combines a percentage at 3 months with a timeframe phrased as time from randomization. Since the study is listed as non-randomized and single-group, the stated time origin is inconsistent with the design description. How the time origin was operationalized is not reported in the registry record. The observed endpoint value and its confidence interval are also not reported in the registry record, so the magnitude and precision of the result cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the intended clinical question and endpoint definition, but it does not provide the primary endpoint result. Although the endpoint is described as a percentage of patients progression-free at 3 months and a 95% confidence interval is specified, neither the observed percentage nor its interval is reported. The result therefore cannot be quantified or assessed for precision from the registry information available.
The record lists enrollment as 28, but enrollment is not the same as the number included in an endpoint analysis. The number assessed at the relevant time point, the number with documented progression or death, and the handling of participants without complete follow-up are not reported in the registry record. No event counts or analysis estimates are listed. The registry reports 0 analyses.
The design also constrains interpretation. With a single non-randomized group and no comparator, any reported outcome would describe the experience of the participants in that group. It would not by itself distinguish an effect of TAS-109 from disease course, participant selection, other care, or measurement and follow-up processes. No causal comparison with another treatment can be made from this design.
The termination status is a study-status fact, not an outcome. The reason for termination is not reported in the registry record. It should not be treated as evidence either for or against the intervention. Likewise, the lack of a posted primary estimate does not establish that the endpoint was not measured; it means the registry record does not give the result.
The serious adverse event summary reports 26 participants at risk and 9 affected in the TAS-109 group. Listed serious-event terms include small intestinal obstruction, disease progression, and pneumonia at 7.7% each, and anaemia, neutropenia, and gastrointestinal obstruction at 3.8% each. These figures describe reported safety events, not the primary efficacy endpoint. The record does not identify event timing, duration, relatedness to TAS-109, or whether a participant could contribute more than one term.
Overall, the available registry entries support a description of the study design, endpoint definition, and selected safety summaries. They do not permit an efficacy estimate, a treatment comparison, or a conclusion about the size or certainty of any treatment effect.
9. Statistical Methods Explained
The registry record supplies a design description and an endpoint definition, but little information about the statistical procedures used to analyze outcomes. The distinction between defining an analysis and reporting its result is important: a planned measure can be stated even when its estimate and uncertainty are absent from the record.
What does the primary endpoint measure?
The endpoint is described as the percentage of patients without progressive disease or death at 3 months of therapy. These are event-based components: a participant is no longer progression-free once progressive disease is documented or death occurs, whichever comes first. The registry also describes a 95% confidence interval as the measure of dispersion. In general, a confidence interval communicates uncertainty around an estimate; its width depends on the data and the analysis. No numerical estimate or interval is reported in the registry record, so neither the endpoint value nor its precision can be judged.
The wording calls the endpoint a percentage, while the registry describes the parameter as a number. The record does not explain this difference in presentation. It also uses a randomization date as the time origin, despite identifying the study as non-randomized. The intended operational definition, including the time origin used in analysis, is not reported in the registry record.
Why does the design matter?
In general, random allocation can help make comparison groups similar in expectation, supporting interpretation of differences between groups. This study is listed as non-randomized and single-group, with no masking. There is no concurrent control group against which to compare the observed outcome. A single-group result can describe what happened among participants receiving the intervention, but it cannot by itself estimate what would have happened to the same participants under a different condition.
Without masking, knowledge of treatment assignment may be possible for participants or study personnel, though the registry does not specify who knew what or whether this influenced assessments. For an endpoint involving documented progression, assessment methods and timing can matter. The registry does not report assessment schedules, independent review, or procedures intended to reduce assessment bias.
What can be learned from a confidence interval?
In general, a confidence interval gives a range of estimates compatible with the data under the method’s assumptions. It is not a guarantee that the true value lies in that particular interval, and it does not correct for design limitations or bias. The 95% confidence level is specified for the primary endpoint, but the interval itself is absent. Without the estimate, interval, and analysis details, the precision of the primary result cannot be evaluated.
What do the planning illustrations mean?
The registry describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For time-to-event planning, the stated method uses a total event count; other planning outputs are expressed as participants per arm. These are planning assumptions, not evidence that the trial used those assumptions in its design. They are also not observed power, and a two-arm equal-allocation framework does not match this study’s listed single-group design.
The registry record does not report the trial’s own sample-size justification or statistical plan. The observed primary effect needed to interpret such planning illustrations is not reported in the registry record. Any planning estimate should therefore be treated as an illustration rather than as a description of the trial’s actual design or performance.
Why does over-dispersion matter in general?
For count outcomes, a simple statistical model may assume that variability follows a particular relationship to the average count. Over-dispersion means the data vary more than that model expects. If it is ignored, uncertainty can be understated and statistical evidence can appear stronger than warranted. This is a general consideration for count data; the registry record does not report an over-dispersion assessment or establish that such a model was used for this trial.
More broadly, the registry provides too little information to identify the estimation method, treatment of censoring, covariate adjustment, or sensitivity analyses. These methods are not reported in the registry record and should not be inferred from the endpoint label alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint and describes secondary objectives that include antitumor activity, objective tumor response, duration of clinical benefit, overall survival, and safety. It lists antitumor activity and overall survival among secondary outcomes and reports 3 outcome measures. The registry record does not provide the full analysis plan or explain how outcomes were prioritized beyond identifying progression-free survival as the primary objective.
When several outcomes or statistical tests are examined, the chance of at least one apparently notable result can increase. In general, multiplicity procedures can address this issue by defining which comparisons are primary or adjusting how evidence is evaluated. The registry record does not report whether any multiplicity adjustment or prespecified testing hierarchy was used. No inference about such procedures is justified from the listed objectives alone.
The record identifies an intent-to-treat population for the primary endpoint, but does not explain its operational definition or report how participants with missing endpoint information were handled. The number included in the endpoint analysis, completeness of follow-up, censoring rules, and any imputation or sensitivity analyses are not reported in the registry record. These omissions matter because missing outcome information can affect both the estimated percentage and the uncertainty around it.
The registry reports 0 analyses, and no numerical primary or secondary outcome estimates are included in the record. Consequently, it is not possible to assess whether results were analyzed according to a prespecified plan, whether all planned outcomes were reported, or how missing data and multiple outcomes were addressed.
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 |
|---|---|---|---|
| TAS-109 | 9 | 26 | 34.6% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| TAS-109 | 26 of 26 |
Most frequent serious adverse event terms
| Event term | Organ system | TAS-109 |
|---|---|---|
| Small intestinal obstruction | Gastrointestinal disorders | 2 of 26 |
| Disease progression | General disorders | 2 of 26 |
| Pneumonia | Infections and infestations | 2 of 26 |
| Anaemia | Blood and lymphatic system disorders | 1 of 26 |
| Neutropenia | Blood and lymphatic system disorders | 1 of 26 |
| Gastrointestinal obstruction | Gastrointestinal disorders | 1 of 26 |
| Pyrexia | General disorders | 1 of 26 |
| Catheter bacteremia | Infections and infestations | 1 of 26 |
| Pleural effusion | Respiratory, thoracic and mediastinal disorders | 1 of 26 |
Most frequent non-serious adverse event terms
| Event term | Organ system | TAS-109 |
|---|---|---|
| Fatigue | General disorders | 14 of 26 |
| Neutropenia | Blood and lymphatic system disorders | 11 of 26 |
| Nausea | Gastrointestinal disorders | 10 of 26 |
| Diarrhoea | Gastrointestinal disorders | 8 of 26 |
| Anorexia | Metabolism and nutrition disorders | 8 of 26 |
| Anaemia | Blood and lymphatic system disorders | 7 of 26 |
| Vomiting | Gastrointestinal disorders | 7 of 26 |
| Constipation | Gastrointestinal disorders | 6 of 26 |
| Alopecia | Skin and subcutaneous tissue disorders | 6 of 26 |
| Leukopenia | Blood and lymphatic system disorders | 4 of 26 |
Serious events with the highest arm-level rate: small intestinal obstruction (7.7%), disease progression (7.7%), pneumonia (7.7%), anaemia (3.8%), neutropenia (3.8%).
The TAS-109 group safety summary lists 26 participants at risk and 9 affected for serious adverse events. The listed serious-event terms are small intestinal obstruction, disease progression, and pneumonia, each at 7.7%; anaemia, neutropenia, and gastrointestinal obstruction, each at 3.8%. These are registry-reported percentages and should be read as event summaries, not as a comparison with another treatment.
The record does not state the denominator used for each listed term, provide event counts alongside the percentages, or specify whether one participant could be represented under more than one term. The terms therefore should not be added together or interpreted as mutually exclusive categories. The registry also does not report timing, duration, severity grading beyond the serious-event classification, or assessed relationship to TAS-109. Disease progression appears among the listed serious events, but the record does not explain how that term relates to the primary endpoint’s progression definition.
The other adverse event summary lists 26 participants at risk and 26 affected. The registry does not provide a detailed breakdown of those events in the registry record for this analysis. These summaries describe reported safety observations; they do not establish whether TAS-109 caused an event or how its safety compares with another option.
12. What the Result Does, and Does Not, Mean
This study addresses a clinically relevant question: whether patients with chemotherapy-refractory advanced colorectal cancer remained free of documented progression or death during the stated follow-up after receiving TAS-109. The registry defines that question using a 3-month progression-free survival percentage and specifies an intent-to-treat population and a 95% confidence interval.
However, the registry record does not report the primary endpoint estimate or its confidence interval. It therefore does not show how many participants met the endpoint, how large the estimated percentage was, or how precisely it was estimated. The record’s enrollment figure cannot substitute for an analyzed sample size or an outcome result. The registry lists 0 analyses.
Even if an outcome estimate were available, the single-group, non-randomized design would limit causal interpretation. Outcomes in the TAS-109 group could reflect several factors, and without a concurrent comparison group the study cannot separate those influences from the intervention. This design does not provide a like-for-like comparison with another treatment.
The listed serious adverse event figures provide some safety information, but they lack details on timing, attribution, and the relationship between event terms and individual participants. They do not establish that TAS-109 caused the events, nor do they support a comparative safety conclusion.
The appropriate interpretation is therefore narrow: the registry record describes a terminated Phase II study, its intended primary endpoint, and selected safety summaries. It does not report enough outcome data to characterize the primary efficacy result or to draw a treatment-effect conclusion. The reason for termination and key analysis details are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it separates a clearly named endpoint from an available result. The registry defines progression-free survival at 3 months and identifies a 95% confidence interval, yet does not report the endpoint estimate or interval. A measure’s definition alone cannot show its observed value or the degree of uncertainty around it.
The design also illustrates why statistical interpretation depends on more than an outcome summary. A non-randomized, single-group study can document outcomes among participants who received TAS-109, but it lacks a concurrent counterfactual group. Even a precise estimate would not remove the limitations created by the absence of a comparator.
There is also a wording issue with practical implications: the endpoint timeframe refers to a date of randomization, while the design is explicitly non-randomized. The registry does not clarify the time origin. Clear alignment between endpoint definitions and study design is essential for reproducible interpretation.
Finally, the planning assumptions described in the record use an equal-allocation, two-arm framework, whereas the trial is listed as single-group. Such planning illustrations are not the same as the actual design rationale or observed statistical power. The trial’s own sample-size justification and statistical plan are not reported in the registry record.
Together, these details show why readers must distinguish endpoint definitions, planning assumptions, safety summaries, and analyzed clinical results. Each answers a different question, and the registry record does not provide the primary result needed to judge the endpoint’s magnitude or precision.
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 is the absence of the primary endpoint estimate and its 95% confidence interval. The registry defines the endpoint but does not report the result, so its magnitude and precision cannot be evaluated. It also does not report the number included in the primary analysis, endpoint event counts, or the extent of follow-up.
The design is non-randomized and single-group, with no concurrent comparator. This limits causal interpretation and prevents a direct comparison with another treatment. The registry lists no masking. Details about outcome assessment procedures and safeguards against assessment bias are not reported in the registry record.
The endpoint description refers to time from randomization, which is inconsistent with the non-randomized design. The record does not explain the time origin used. It also describes the primary endpoint as a percentage while identifying the parameter as a number; this difference is not explained.
The record does not report the reason for termination, the trial’s sample-size justification, a full statistical analysis plan, interim analyses, missing-data methods, censoring rules, or multiplicity procedures. It lists 0 analyses. Safety summaries lack details on event timing, attribution, and whether event categories overlap. These gaps restrict assessment of both efficacy and safety and should not be filled by assumptions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Phase II Study of TAS-109 to Treat Advanced Colorectal Cancer — NCT00824161.
- Registry record last updated 2012-04-23; status last verified 2012-04.
- Results first posted 2011-08-17.
- 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
NCT00824161 is a Phase II, non-randomized, unmasked, single-group study of TAS-109 for chemotherapy-refractory advanced colorectal cancer. TAS-109 was described as a continuous intravenous 14-day infusion. Enrollment was listed as 28; the study status is terminated. The reason for termination is not reported in the registry record.
The primary endpoint was the percentage of patients without progressive disease or death at 3 months, with a 95% confidence interval specified. The registry identifies an intent-to-treat population but does not report the endpoint estimate or interval. The timeframe’s reference to randomization does not align with the non-randomized design, and the time origin used is not reported.
The safety summary lists 26 at risk and 9 affected for serious adverse events in the TAS-109 group. Selected serious-event terms are reported as percentages. The record lists 3 outcome measures and 0 analyses. The primary efficacy result, analysis details, and reason for termination are not reported in the registry record.