Study of Hsp90 Inhibitor, STA-9090 for Relapsed or Refractory Small Cell Lung Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of Hsp90 Inhibitor, STA-9090 for Relapsed or Refractory Small Cell Lung Cancer (NCT01173523), a non-randomized phase 2 study. The primary outcome is 8-Week Progression-Free Rate.

2. Clinical Question

3. Trial Design

This was a phase II study with non-randomized allocation and a single-group model. The registry record lists an enrollment of 25 and gives the study status as completed. The study start date is 2010-07-28 and the primary completion date is 2013-06-07. The sponsor is listed as David M. Jackman, MD.

STA-9090 was administered intravenously once weekly in weeks 1, 2, and 3 of a 4-week cycle, at a dose of 200mg/m2. Treatment was to continue until progressive disease or unacceptable toxicity. The record describes baseline stratification into Cohort A and Cohort B according to prognostic groups. The cohort descriptions are incomplete in the registry record, so the criteria defining the groups cannot be fully characterized from this information.

The study did not use random assignment, masking, or a concurrent control arm. Cohort membership does not create a randomized comparison: any differences between the cohorts could reflect their prognostic characteristics or other differences, rather than a treatment effect. The record also does not state that the cohorts were intended to serve as controls for each other.

The primary outcome was the 8-week progression-free rate. Secondary outcomes listed in the record were overall response rate, progression-free survival, and overall survival. Although the record marks the study completed, it does not report numerical results for the primary endpoint or those secondary outcomes. The planned statistical analysis, including the approach to between-cohort analyses, is not reported in 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analysis dataset is comprised of all treated patients.

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: The analysis dataset is comprised of all treated patients.

6. Primary Endpoint

The registry lists the primary outcome as 8-Week Progression-Free Rate, measured over Disease was evaluated radiographically at baseline and every 8 weeks on treatment; Treatment continued until disease progression or unacceptable toxicity. Relevant for this endpoint was the first 8 week disease re-assessment..

The primary endpoint was the percentage of participants who achieved complete response, partial response, or stable disease by the first disease assessment at 8 weeks. Disease was evaluated radiographically at baseline and every 8 weeks during treatment. The endpoint therefore focuses on disease status at a specified early reassessment, rather than measuring the duration of disease control over the whole treatment period.

The response categories were defined using RECIST 1.1. For target lesions, complete response required disappearance of all target lesions. Partial response required a decrease of at least 30% in the sum of the longest diameters, relative to baseline. Stable disease meant that neither the required decrease for partial response nor the progression threshold was reached. Progressive disease for target lesions was defined as an increase of at least 20% from the smallest sum recorded on study, with an absolute increase of at least 5 mm. Response required confirmation within 4 weeks. The definition also specified that progression-free status for non-target lesions required no new lesions, no unequivocal progression in existing non-target lesions, or that these lesions were not evaluated.

As a general statistical matter, an early disease-control endpoint can describe the fraction meeting a prespecified status at a particular assessment. It does not, by itself, convey how long that status persisted or establish what would have occurred under another treatment. The registry record identifies a 95% confidence interval as the endpoint’s dispersion measure, but does not report the endpoint estimate or interval.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary endpoint estimate?

The endpoint is a proportion: the percentage of participants classified as having complete response, partial response, or stable disease at the first assessment scheduled for 8 weeks. It is a fixed-time measure. It does not summarize the length of time participants remained progression-free after that assessment, and it is not the same as progression-free survival. The endpoint rules specify RECIST 1.1 response criteria, including thresholds for changes in target-lesion measurements and confirmation of response within 4 weeks.

The registry record identifies the dispersion measure as a 95% confidence interval. In general, a confidence interval conveys uncertainty around an estimate under the assumptions of the method used. A narrower interval indicates greater statistical precision, while a wider interval indicates less precision. The interval does not guarantee that the underlying value lies within its limits, nor does it address possible bias in the study design or outcome ascertainment. In this record, neither the estimated rate nor its interval is reported, so its precision cannot be assessed.

What does the design allow?

The study is listed as non-randomized and single-group. In a randomized controlled design, random assignment can help make groups comparable at baseline, supporting a treatment-versus-control contrast. That design feature is absent. The cohort labels reflect prognostic stratification, and the registry does not establish them as an untreated or alternative-treatment comparison group. Accordingly, the design can describe outcomes among participants receiving STA-9090, but does not isolate what difference the treatment made relative to another course of care.

As a general principle, uncontrolled results can be affected by participants’ underlying disease characteristics, selection into the study, changes in care, and how outcomes are measured. These considerations are especially relevant when interpreting outcomes that might also occur without the study treatment. They cannot be resolved by comparing the named cohorts unless the comparison was planned, appropriately analyzed, and supported by adequate adjustment; that analysis plan is not reported in the registry record.

How should event counts be read?

The serious and other adverse-event figures are counts with cohort-specific numbers at risk. Counts describe the recorded events or participants affected as classified in the registry. They are not estimates of a treatment effect, and a numerical contrast between cohorts would not account for their non-randomized formation. General comparisons of event frequencies also need consistent definitions, observation periods, and complete reporting. The registry information does not give enough detail to establish all of those features.

The record names several serious adverse-event terms and their percentages. Those values describe the reported terms; they do not on their own establish causality, severity for an individual participant, or how the risks compare with another treatment. The record lists no deaths in either cohort. That entry should be read as the posted count, not as proof that no other safety concern occurred.

What statistical plan is available?

The registry record does not report a statistical analysis plan, a planned hypothesis test, an adjustment strategy, or the handling of multiple outcomes. No analyses are listed. It also does not report how missing assessments were handled, whether participants without an 8-week assessment were counted in a particular way, or how any censoring was defined for time-to-event outcomes. These details can affect interpretation and cannot be reconstructed from the endpoint definition alone.

As a general matter, a confidence interval or significance test only has its intended interpretation when its analysis assumptions and population are suitable. The endpoint record says the analysis dataset comprised all treated patients, but does not state the number included in that dataset or provide the endpoint result. No re-calculation or sample-size illustration can fill that gap. Sample-size planning illustrations, where present, are not observed power and do not substitute for the study’s unreported results.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Cohort A: STA-9090", "Cohort B: STA-9090")
n      <- c(13, 12)
events <- c(0, 1)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Cohort A: STA-9090  13  0  0.0  0.0  24.7  0.0  22.8  0.2  23.2
ARM  Cohort B: STA-9090  12  1  8.3  0.2  38.5  1.5  35.4  1.9  36.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and secondary outcomes of overall response rate, progression-free survival, and overall survival. It does not report how statistical testing across these outcomes was planned, whether any multiplicity adjustment was intended, or whether the secondary outcomes were exploratory. The record lists no analyses. Without a stated plan and posted results, it is not possible to determine which comparisons were made or how the risk of false-positive findings across multiple tests was addressed.

The primary endpoint analysis population is described as all treated patients. The registry record does not state the number included in that analysis, how many had an evaluable 8-week assessment, or how missing assessments were handled. It does not report whether missing endpoint data were excluded, classified as failures, imputed, or addressed using another method. Those choices can affect a proportion-based endpoint, so the outcome estimate cannot be interpreted fully without them.

For progression-free survival and overall survival, the registry record does not report censoring rules, analysis populations, or methods for handling incomplete follow-up. It also does not describe interim analyses or stopping rules; those details are not reported in the registry record. No assumptions about them should be inferred from the study’s completed status.

As a general statistical principle, prespecified outcome definitions and analysis rules help distinguish planned analyses from choices made after data are observed. The registry provides an endpoint definition and a nominal confidence-interval level, but not the broader statistical plan or numerical endpoint findings. The uncertainty and potential effects of missing data therefore remain unquantified.

12. 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: hyponatremia (25.0%), abdominal distension (8.3%), abdominal pain (8.3%), alanine aminotransferase increased (8.3%), alkaline phosphatase increased (8.3%).

The registry reports serious and other adverse-event counts separately for Cohort A and Cohort B. For serious adverse events, 4 were affected among 13 at risk in Cohort A, and 3 among 12 at risk in Cohort B. For other adverse events, the respective counts were 7 among 13 and 8 among 12. The record lists 0 deaths for each cohort. These values should be read with their stated denominators; they are not evidence of a difference between treatments because there was no randomized comparator.

The listed serious adverse-event terms include hyponatremia at 25.0%. Abdominal distension, abdominal pain, alanine aminotransferase increased, alkaline phosphatase increased, and allergic reaction are each listed at 8.3%. The registry record does not provide enough detail to infer causality or make comparisons with another treatment. An event term and percentage are descriptive safety information, not a causal assessment.

General considerations for interpreting safety data include the definition of an event, the period over which it was collected, and whether the count refers to participants or event episodes. The record provides the stated figures but does not report all details needed to resolve those questions. Counts should not be converted into additional rates or treated as comparative evidence.

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

The registry record establishes that a phase II study of STA-9090 in relapsed or refractory small cell lung cancer was completed and describes the treatment schedule and primary endpoint. It also gives descriptive adverse-event counts by prognostic cohort. Those details characterize the study and the safety information posted in the record.

The record does not report the observed 8-week progression-free rate, its confidence interval, or the numerical findings for the listed secondary outcomes. Consequently, readers cannot determine from this record how many participants met the primary endpoint, how precise the estimate was, or what the study found for response, progression-free survival, or overall survival. A completed study status does not supply those missing results.

Because allocation was non-randomized and the model was single-group, the record does not support a controlled estimate of the effect of STA-9090 compared with another treatment or no treatment. The cohorts were described as prognostically stratified, and their full criteria are not reported. Cohort-specific event counts should not be treated as if they came from treatment and control groups.

As a general interpretation principle, a study’s design and the completeness of its results constrain what can be concluded. An endpoint definition tells readers what was intended to be measured; it does not reveal the observed outcome. Likewise, adverse-event counts describe the recorded safety experience but do not establish that treatment caused an event or show how the experience compares with an alternative.

The appropriate reading is therefore limited to the study structure, stated outcome definitions, and the posted safety counts. Broader conclusions about efficacy, comparative benefit, or comparative safety cannot be drawn from the registry information in the record.

14. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a defined endpoint and an available endpoint result. The registry specifies a clinically interpretable fixed-time measure: the percentage meeting response or stable-disease criteria at the first assessment scheduled for 8 weeks. It also describes the RECIST 1.1 criteria used to classify disease status. Yet the estimate and its confidence interval are not reported in the registry record. Readers can understand what was to be measured, but cannot quantify the observed result or its uncertainty.

The design also illustrates why cohort labels do not necessarily imply a controlled comparison. The study is described as non-randomized and single-group, with baseline prognostic stratification into Cohort A and Cohort B. Without random assignment to different treatments and a specified comparative analysis, differences between these groups cannot be interpreted as treatment effects. The incomplete cohort descriptions further limit interpretation of any group contrast.

Safety counts are posted with cohort-specific denominators, making their descriptive scope clearer than that of the unreported primary outcome. Even so, they do not provide a randomized safety comparison. The record’s serious adverse-event terms and percentages should be interpreted as registry descriptions rather than causal or comparative estimates.

As a general lesson in biostatistics, clear outcome definitions, appropriate design, transparent analysis methods, and complete result reporting all contribute different pieces of evidence. None substitutes for the others. This record offers endpoint definitions and selected safety information, but not the numerical primary outcome findings or a reported statistical analysis plan. That separation matters when judging what can—and cannot—be inferred from a clinical trial record.

15. 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 central limitation for interpreting this study record is the absence of numerical results for the primary endpoint. The registry describes the 8-week progression-free-rate definition and identifies a 95% confidence interval, but does not report the estimated rate, the interval, or the number meeting the endpoint. It also does not give numerical findings for the listed secondary outcomes.

The study was non-randomized and single-group, so it does not provide a randomized treatment comparison. Cohort A and Cohort B were formed through baseline prognostic stratification, and the full criteria separating them are not reported in the registry record. Their outcomes, even if available, would not automatically be comparable as treatment and control results.

The endpoint analysis population is described as all treated patients, but the record does not state the number in that population or how missing 8-week assessments were handled. The statistical analysis plan, multiplicity strategy, and methods for time-to-event outcomes are not reported in the registry record. The record lists no analyses.

Safety findings are limited to the posted cohort-level counts and listed serious adverse-event terms. The registry information does not establish causality or provide a comparison with another treatment. These limitations restrict both the precision of interpretation and the conclusions that can be drawn about treatment effects or comparative safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of Hsp90 Inhibitor, STA-9090 for Relapsed or Refractory Small Cell Lung Cancer — NCT01173523.
• Registry record last updated 2019-04-16; status last verified 2019-04.
• Results first posted 2017-04-11.
• 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.

19. Record Summary

The registry record describes a completed phase II study of STA-9090 for relapsed or refractory small cell lung cancer. The design was non-randomized and single-group, with baseline prognostic stratification into Cohort A and Cohort B. STA-9090 was administered intravenously once weekly in weeks 1, 2, and 3 of a 4-week cycle at 200mg/m2, until progression or unacceptable toxicity.

The primary endpoint was the percentage of participants with complete response, partial response, or stable disease at the first assessment scheduled for 8 weeks, using RECIST 1.1 criteria. The record does not report the primary endpoint result or its confidence interval. It also lists secondary outcomes of overall response rate, progression-free survival, and overall survival without numerical results.

Safety information includes serious and other adverse-event counts by cohort, listed serious-event terms, and 0 deaths in each cohort. These are descriptive figures and do not constitute a randomized comparison. The analysis plan and key details about missing data are not reported in the registry record.