Ruxolitinib for Adult T-Cell Leukemia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ruxolitinib for Adult T-Cell Leukemia (NCT01712659), a non-randomized phase 1, phase 2 study. The primary outcome is Phase II: Best Response.

2. Clinical Question

The study combines a Phase II response question with Phase I dose-finding and safety questions. The registry describes the intended response measure as the count of participants whose best response was CR or PR. It also lists time to progression and survival time as Phase II secondary outcomes, and adverse-event and time-to-progression outcomes for Phase I.

The clinical question is therefore not whether ruxolitinib performs better than a control treatment. It concerns the observed response and safety experience in the enrolled cohorts. Because treatment allocation was not randomized and no separate comparator is listed, differences between dose cohorts would not, by themselves, establish that dose caused a difference in outcome. Cohorts may differ in ways that the registry record does not describe.

The registry reports enrollment of 19 participants. The primary response count and a detailed Phase II analysis are not reported in the registry record. The clinical question can be identified, but the posted information does not give the response result needed to answer it.

3. Trial Design

This was a Phase I/II, non-randomized, single-group trial sponsored by the National Cancer Institute (NCI). The registry lists no masking. The trial began on 2012-10-26, had a primary completion date of 2021-11-12, and is listed as terminated. Enrollment was 19 participants. The reason for termination is not reported in the registry record.

The record describes an original Phase II cohort receiving ruxolitinib 20 mg orally twice daily for 28 days, with treatment potentially continuing until progressive disease or unacceptable toxicity. It also describes Phase I dose-escalation cohorts, including a 30 mg dose level and a 40 mg dose level, each administered orally twice daily. The dose-escalation description is incomplete in the registry record, so the full dosing and escalation details are not reported there. A Phase I dose-expansion cohort is described as receiving the maximum tolerated dose or maximum administered dose defined in dose escalation; its continuation conditions include progressive disease or unacceptable toxicity.

These are treatment cohorts within a non-randomized study, not randomized arms with a common concurrent control. The Phase I component was intended to assess dose-related safety, including determination of a maximum tolerated dose. The Phase II primary outcome was best response, defined as CR plus PR. The registry also lists secondary outcomes for progression, survival, and adverse events.

The record does not report a sample-size justification, a detailed statistical analysis plan, interim-analysis procedures, or the reason the study was terminated. Those design details should not be inferred from the phase labels or the total enrollment. The posted registry information identifies the broad trial structure and outcomes, but does not provide the complete protocol-level methods needed to reconstruct all study procedures.

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 participants were enrolled on dose level 3 or the expansion cohort for the phase I dose escalation version of the protocol because the adult T-cell leukemia (ATL) research program was terminated after the death of the T-cell malignancy group Lead investigator.

Dose Escalation

Reasons for not completing this period:

Dose Expansion

Reasons for not completing this period:

Participants Re-Enrolled and Treated

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Phase II: Best Response, measured over From the time of the start of treatment to approximately 3 years of 5.

The primary Phase II endpoint is best response, expressed as the count of participants with complete response (CR) or partial response (PR). Combining these categories produces a binary response outcome for each participant: the participant either met the registry’s definition of CR or PR as best response, or did not. The endpoint is intended to capture the strongest recorded tumor response during the assessment period, rather than the duration of response.

The registry says response was measured using the Revised Response Criteria for Lymphoma by Cheson and colleagues and the International Consensus Meeting Criteria for Adult T-Cell Lymphoma. It defines CR as disappearance of all clinical, microscopic, and radiographic evidence of disease. PR is defined as at least a 50% reduction in the sum of the products of the greatest diameters of measurable disease without the appearance of new lesions. Stable disease means criteria for CR, PR, or progressive disease were not met. The registry also gives definitions of progressive disease in peripheral blood and the appearance of new lesions.

As a general statistical concept, a response endpoint can provide a direct summary of whether participants met a prespecified category during assessment. It does not, by itself, describe how long a response lasted, how quickly it occurred, or what happened after progression. Those questions require separate outcomes, such as the listed time-to-progression and survival measures.

The registry timeframe wording is “From the time of the start of treatment to approximately 3 years of 5.” This wording is unclear. The number of participants with CR or PR is not reported in the registry record, so the endpoint definition is available but its result cannot be stated from the posted information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design estimate?

The registry classifies the trial as non-randomized and single-group, with no masking. In a single-group study, outcome summaries describe participants who received the study intervention. Without a randomized comparator, the observed outcomes do not isolate the effect of treatment from other explanations, such as the natural course of disease, participant selection, or changes in care over time. These are general features of the design; the registry record does not report analyses that address such explanations.

The trial includes Phase I and Phase II components. In general, dose escalation studies examine tolerability across planned dose levels and may use observed toxicities to guide dose decisions. Here, the registry describes the Phase I objective as determining a maximum tolerated dose, but the complete escalation rules, decision criteria, and dose-limiting-toxicity results are not reported in the registry record. The Phase II primary outcome is a response count. The registry record does not report the detailed method used to combine or interpret results across the Phase I and Phase II cohorts.

How should a response count be interpreted?

The primary endpoint counts participants with CR or PR as best response. This is a binary outcome at the participant level, even though the underlying response assessment uses clinical, microscopic, radiographic, and measurable-disease criteria. A response count is most informative when accompanied by the number assessed and an uncertainty interval. The number of responders and a confidence interval for the primary endpoint are not reported in the registry record.

As a general statistical concept, a confidence interval describes a range of values compatible with the data under a specified statistical model and procedure. It communicates estimation precision; it is not a guarantee that the true value lies within the interval. With small samples, intervals are generally wide, so estimates may remain uncertain even when a point estimate appears straightforward. No interval for the primary response outcome is reported in the registry record, and one cannot be reconstructed without the relevant response count and denominator.

What do the adverse-event counts show?

The posted serious adverse event figures are counts of participants affected and at risk in the listed cohorts. The figures report zero affected for the serious events category in each of the three cohorts with counts shown. Such counts are descriptive. In general, zero observed events in a finite group does not establish absence of risk, and the precision of an estimate depends on the amount of information available. The registry does not provide a confidence interval for these serious adverse-event counts.

The record separately lists other adverse events affecting all participants at risk in those same three cohorts, and it gives cohort-specific death counts. Those categories should not be conflated: the record does not say that every listed death was caused by treatment, and the serious-event figures are specifically labeled as related to the experimental treatment. The registry record does not provide the detailed serious-event terms, since its list of top serious terms is empty.

Why does over-dispersion matter?

As a general statistical concept, over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors too small and confidence intervals too narrow if the model does not account for the extra variability. This matters for outcomes such as event counts when participants’ outcomes are more heterogeneous than a simple model expects. The registry’s primary endpoint is a participant count, and the record does not report a model or dispersion estimate for it. No claim about over-dispersion in this trial can be made from the posted information.

What can planning calculations say?

As a general concept, sample-size planning calculations describe how many participants might be needed under specified assumptions about the target effect, statistical test, allocation, and error rate. They are planning illustrations, not results observed in a trial. The registry’s stated planning framework refers to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it also describes the effect to detect as a stated fraction of the observed effect. For time-to-event outcomes, the framework refers to total events, while other outcomes are expressed as participants per arm.

Those assumptions do not change the actual study design: the trial is non-randomized and single-group, not an equal-allocation, two-arm randomized comparison. Planning illustrations cannot be treated as observed power, nor do they supply evidence that the study was adequately sized for its actual analyses. The registry record does not report the trial’s own sample-size justification or the full analysis plan. No numerical planning results are stated in the registry information used for this interpretation.

What is not available about the analysis?

The registry reports 0 analysis records. It does not report a detailed statistical plan, analysis populations, missing-data methods, multiplicity procedures, or the actual primary response analysis. It is therefore not possible to determine from the record whether outcome assessments were analyzed by intention-to-treat, by participants with evaluable assessments, or by another defined population. These are not interchangeable choices: the analysis population and handling of missing observations can affect the interpretation of a response count. The absence of these details means that conclusions about the analysis methods should remain limited to the information explicitly listed in the registry.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one Phase II primary outcome, best response, and several secondary outcomes: time to progression, survival time, Phase I adverse events, and time to progression at specified dose levels. Considering multiple outcomes can raise a multiplicity issue. As a general statistical concept, when many hypotheses are tested, the chance of at least one apparently unusual result can increase unless the analysis plan addresses that feature. The registry record does not report a multiplicity adjustment, a hierarchy of testing, or a detailed plan for interpreting secondary outcomes. It is not possible to determine whether any adjustment was intended or used.

Missing-data handling is also not reported in the registry record. The entry does not give the number of participants assessed for the primary response endpoint, the number with missing or unevaluable assessments, or how any such observations were handled. In general, response estimates can depend on the analysis population and on whether participants without an evaluable assessment are included, excluded, or classified under a prespecified rule. No such rule can be inferred.

The record reports no analysis records and does not identify an analysis population for the primary outcome. It also does not state whether participants who discontinued treatment, progressed, or had incomplete follow-up remained in each analysis. The distinction between enrollment and endpoint evaluation is important: the enrollment total is not automatically the denominator for every reported outcome.

The registry status is terminated, but the reason is not reported in the registry record. The record also does not report interim-analysis procedures or stopping rules. These omissions do not establish that such procedures were absent from the protocol; they mean that they cannot be described from the registry record.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The serious adverse event figures list the number at risk and the number affected in each cohort. In the original Phase II standard-dose cohort, 0 of 12 were listed as affected; in the 30 mg Phase I dose-escalation cohort, 0 of 6 were listed as affected; and in the 40 mg cohort, 0 of 1 were listed as affected. The record labels these as serious adverse events related to the experimental treatment.

These counts should be interpreted as the registry’s reported observations for those cohorts. They do not establish that the true risk is zero, particularly where the number at risk is small. As a general statistical point, a zero count can coexist with substantial uncertainty about an event’s underlying frequency. The registry does not report uncertainty intervals for these figures, and its list of top serious-event terms is empty.

The record separately lists other adverse events affecting 12, 6, and 1 participants in those cohorts, respectively. It also lists deaths of 11, 3, and 0. These other-event and death counts are not equivalent to treatment-related serious adverse events. The posted registry entries do not state the cause or treatment attribution for the deaths. A full safety interpretation would require event descriptions, timing, severity, attribution, exposure, and follow-up details, which are not reported in the registry record.

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

The registry record establishes that NCT01712659 was a non-randomized Phase I/II study of ruxolitinib in adults with smoldering and chronic ATL, with enrollment of 19 participants. It defines the Phase II primary endpoint as the count of participants whose best response was CR or PR and describes response criteria. It also posts selected adverse-event and death counts for three dose cohorts.

Those details do not provide the primary response count, the number evaluated for response, or a precision estimate. The posted information therefore does not allow a numerical assessment of the Phase II response outcome. It also does not provide a randomized comparison, so it cannot estimate a treatment difference against a control group. The non-randomized dose cohorts should not be treated as if they were interchangeable groups assigned by chance.

The serious adverse-event counts are descriptive observations, not proof that serious treatment-related events cannot occur. The death counts are listed separately, and treatment attribution is not reported in those figures. The available data do not establish the cause of termination, the complete safety profile, or the results of the listed time-to-progression and survival outcomes.

As a general statistical principle, an endpoint definition, an observed estimate, and a causal conclusion are different things. A clear endpoint definition tells readers what was intended to be measured; a reported count and denominator summarize observed data; and a causal comparison requires a design and analysis that support that interpretation. In this record, the endpoint definition is available, but the primary response result and analysis details are not reported.

The appropriate reading is consequently limited: the record describes the trial’s structure and certain cohort-level counts, while leaving key efficacy and analysis information unavailable. Neither the phase designation nor the fact that a study was conducted supplies the missing outcome results.

13. Why This Trial Matters Statistically

This trial is statistically notable for combining dose-finding and response assessment in a rare cancer setting while using a non-randomized, single-group design. The registry enrollment is 19, and its safety figures include small dose cohorts. These features make transparent reporting of denominators, uncertainty, and analysis populations especially important for readers assessing how much information each result contains.

The primary outcome is a count of participants with CR or PR, but the registry does not report the count or the number assessed. That gap illustrates why an endpoint definition alone is not enough to evaluate an outcome. Readers need the observed numerator and denominator, and, where appropriate, an uncertainty interval, to judge the precision of an estimate.

The study also illustrates the distinction between dose escalation and comparative evaluation. Dose cohorts may address questions about tolerability and dose selection, but without randomization and a concurrent comparator, differences between cohorts cannot automatically be attributed to dose. The registry does not report the full escalation rules or cohort-level adjusted analyses, so the posted record supports only a limited description of those aspects.

Finally, the separate listing of related serious adverse events, other adverse events, and deaths highlights the importance of keeping safety categories distinct. Zero reported treatment-related serious adverse events in the listed groups is a count, not a guarantee of no risk. Death counts require context and attribution before they can be interpreted in relation to treatment. Overall, this record shows why statistical interpretation depends not just on the named endpoint, but also on complete outcome reporting, study design, and the amount of information behind each estimate.

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 consequential limitation of the available registry information is that the primary response count and the number assessed are not reported. The response endpoint can be defined, but its observed result and precision cannot be evaluated. The record also reports 0 analysis records and does not provide the detailed statistical analysis plan or analysis population.

The study is non-randomized and single-group, with no separate comparator. It therefore does not support a randomized estimate of the difference between ruxolitinib and another intervention. The record does not report participant characteristics by cohort or adjustments that might address differences among cohorts. Consequently, comparisons across dose groups should be treated as descriptive rather than causal.

The registry describes the 20 mg standard-dose cohort and dose escalation at 30 mg and 40 mg, but the dose-escalation description is incomplete. The full dose schedule and escalation criteria are not reported in the registry record. The primary endpoint timeframe wording is also unclear, and the reason for termination is not reported.

The available safety details are limited. The serious adverse event term list is empty, and event-level descriptions, timing, exposure duration, and treatment attribution for deaths are not provided in the listed figures. The cohort counts are small, so zero serious treatment-related events should not be read as a precise estimate of absence of risk. Follow-up completeness and the handling of missing outcome assessments are also not reported.

Finally, the registry lists secondary outcomes but does not report their results or procedures for handling multiple outcomes. It does not report interim analyses, stopping rules, or a trial-specific sample-size justification. These limitations describe the boundaries of the registry information; they do not establish what may or may not have appeared in other study documents.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Ruxolitinib for Adult T-Cell Leukemia — NCT01712659.
• Registry record last updated 2023-01-10; status last verified 2022-12.
• Results first posted 2023-01-10.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT01712659 is a National Cancer Institute-sponsored Phase I/II, non-randomized, single-group trial of ruxolitinib in adults with smoldering and chronic adult T-cell leukemia. Enrollment was 19. The trial began on 2012-10-26, had a primary completion date of 2021-11-12, and is listed as terminated.

The primary Phase II outcome is best response, defined as the count of participants with complete or partial response. The registry also lists progression, survival, and adverse-event outcomes. It reports selected serious adverse-event and death counts for three cohorts, but the primary response count, analysis population, detailed statistical plan, and reason for termination are not reported in the registry record. No analysis records are listed.