A Sequential Two-Stage Dose Escalation Study to Evaluate the Safety and Efficacy of Ruxolitinib: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Sequential Two-Stage Dose Escalation Study to Evaluate the Safety and Efficacy of Ruxolitinib (NCT01776723), a non-randomized phase 1, phase 2 study. The primary outcome is The Maximum Tolerated Dose (MTD) of Ruxolitinib for the Treatment of Myelomonocytic Leukemia (CMML).

2. Clinical Question

3. Trial Design

This was a completed Phase I/Phase II study sponsored by H. Lee Moffitt Cancer Center and Research Institute. The registry lists an enrollment of 50, a start date of 2013-02-20, and a primary completion date of 2018-11-28. It identifies the allocation as nonrandomized, the model as single group, and masking as none. These features describe a dose-finding and treatment study, not a blinded randomized comparison.

The first stage was dose escalation. The registry describes a rolling six Phase I design, starting at 10 mg/d with twice-a-day dosing. The adverse-event groups identify Phase I dose levels of 10 mg, 20 mg, 30 mg, and 40 mg. In the second stage, participants received treatment at the MTD. The record does not state the dose selected as the MTD, nor does it provide the numbers enrolled at each dose level as a trial-flow account.

For a dose-escalation study, the purpose of the early stage is to assess toxicity across dose levels and identify a dose that meets the protocol’s safety definition. The later stage then evaluates treatment at the selected dose. That structure does not by itself establish comparative efficacy, because there is no concurrent randomized control group described in the record. The registry lists secondary outcomes including AML transformation, median overall survival, and duration of response, but their results are not reported in the registry record from the registry record. Sample-size justification, interim analyses, and a fuller statistical analysis plan are 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

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 The Maximum Tolerated Dose (MTD) of Ruxolitinib for the Treatment of Myelomonocytic Leukemia (CMML), measured over 17 weeks.

The primary endpoint is the maximum tolerated dose of ruxolitinib for treating CMML. It is expressed as a dose in mg and is defined by a toxicity rule rather than by a comparison of clinical outcomes between treatment groups. The Phase I definition selects the highest dose at which less than 33% of participants experience a drug-related predefined DLT during the stated timeframe of 17 weeks.

The record specifies which toxicities count toward that rule: any grade 4 hematologic toxicity and any grade 3 or greater non-hematologic toxicity, with an exception for nausea controlled by antiemetic therapy. It also excludes grade 3 metabolic or electrolyte abnormalities that are not clinically significant and are adequately controlled within 72 hours. The definition references NCI Common Terminology Criteria for Adverse Events version 4.0.

In general, a toxicity-based endpoint is used in early dose-finding because it provides a prespecified way to balance dose intensity against unacceptable toxicity. It is not a direct measure of tumor response, survival, or comparative treatment benefit. The registry record does not report the observed DLT counts by dose, the dose selected, or the primary endpoint result. Therefore, the endpoint’s definition can be described, but its result cannot be determined from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial’s method is best understood as dose finding followed by treatment at the selected dose. Its registry design labels are Phase I and Phase II, nonrandomized allocation, no masking, and a single-group model. These labels matter because standard comparisons between randomized treatment arms do not apply. Dose groups are not created through random allocation, and the Phase II MTD group represents a different stage from the Phase I escalation groups.

How does the MTD rule work?

The registry defines MTD as the highest dose where less than 33% of participants experience a drug-related predefined DLT. This is a threshold rule: it uses the observed toxicity experience at each dose level to guide dose selection. A DLT is not simply any adverse event. The record defines it using toxicity grade, type, attribution, and stated exceptions, and specifies a 17-week timeframe for the primary endpoint. The record does not provide the dose-specific DLT counts or the selected MTD, so the application of the rule cannot be reconstructed from the listed adverse-event summaries.

In general, dose-finding designs use sequential information to decide whether subsequent participants should receive a higher, lower, or continued dose. The record names a rolling six design. That label describes the Phase I approach, but the registry entries do not specify the full decision algorithm, cohort-by-cohort decisions, or any deviations from the planned escalation. Those details are not reported in the registry record. The adverse-event groups show dose levels of 10 mg, 20 mg, 30 mg, and 40 mg, but these group entries do not by themselves supply the DLT data required to determine the MTD.

What can the adverse-event counts tell us?

The counts describe participants recorded as at risk and affected for serious and other adverse events in each group. A participant count is not necessarily an event count: one participant may have more than one event, and the summary entries do not provide event timing, recurrence, severity breakdown by event, or the full relation of each event to study treatment. Serious adverse events are also not equivalent to dose-limiting toxicities. The registry’s primary DLT definition includes specific grade and event-type conditions; the general serious-event category has a different scope.

For that reason, these safety entries should be read as descriptive summaries. They do not establish causal relationships, and they cannot be used to calculate the primary MTD endpoint without the required DLT classification and dose-level denominator information. No additional statistical model for safety is reported in the registry record.

What does the record say about inferential analysis?

The registry entries list five outcome measures and zero analyses. No p-value, confidence interval, effect estimate, or model-based result is reported for the primary endpoint or the named secondary outcomes. In general, a p-value assesses compatibility between data and a specified null model, while a confidence interval conveys uncertainty about an estimate under a statistical model. Neither can be interpreted without the estimate, analysis method, and endpoint definition. Since those inferential results are not reported in the registry record, conclusions about statistical significance or precision are not available.

The record also does not report whether analyses were adjusted for baseline factors, how repeated measurements were handled, or which analysis population was used. These choices can affect interpretation. Their absence means that no adjusted treatment effect or population-specific estimate should be inferred from the descriptive counts.

How should planning illustrations be interpreted?

Any sample-size illustrations associated with the posted analysis are planning scenarios, not observed power and not the trial’s original design justification. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect set as a stated fraction of an observed effect. The registry entries do not define a single comparison from which an observed treatment effect for this single-group, nonrandomized dose-finding study can be taken. Thus such illustrations do not describe the actual allocation, establish the original enrollment rationale, or show the probability that the completed study would detect a treatment effect. The trial’s sample-size justification is not reported in the registry record.

General statistical point: over-dispersion occurs when count data vary more than a simple model expects. A model that ignores it can understate uncertainty. The registry entries do not report a count model or an over-dispersion assessment, and the primary endpoint is specified as a dose determined by a toxicity threshold, not as a count outcome model. No claim about over-dispersion or model adequacy can therefore be made for this trial.

10. Multiplicity, Missing Data and Analysis Populations

The record names a primary endpoint and lists secondary outcomes including AML transformation, median overall survival, and duration of response. It also reports five outcome measures overall and zero analyses. The registry entries do not describe a multiplicity procedure, a hierarchy of secondary hypotheses, or whether any outcomes were exploratory. Such procedures matter when several outcomes are tested, because interpreting many tests without an adjustment can increase the chance of a false-positive finding. In this record, however, no inferential results are reported, so no multiplicity-adjusted or unadjusted result can be evaluated.

Missing-data methods are not reported in the registry record. The record does not state how participants with incomplete follow-up, missing toxicity assessments, or unavailable response and survival information were handled. It also does not describe censoring rules for survival outcomes or the denominator used for each outcome analysis. Without these details, the completeness and representativeness of outcome estimates cannot be assessed.

Analysis populations are not reported in the registry record. For example, it does not specify whether the primary endpoint used all enrolled participants, only those who received treatment, or a defined evaluable group. This distinction can matter in dose-finding because participants who cannot be assessed within the endpoint timeframe may affect the interpretation of dose-level toxicity. No participant flow or analysis-population definition is included in the registry record used for this interpretation.

These omissions do not demonstrate that the study lacked a protocol or analysis plan; they mean only that the relevant methods are not reported in the registry record. As a result, readers cannot assess how missing observations, multiple outcomes, or analysis-population choices may have influenced the reported summaries.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death nos (100.0%), diarrhea (50.0%), fatigue (50.0%), vascular disorders -other (25.0%), heart failure (25.0%).

The serious-adverse-event group entries report 6 of 6 affected at the 10 mg Phase I level, 4 of 4 at the 20 mg level, 1 of 5 at the 30 mg level, 1 of 5 at the 40 mg level, and 15 of 30 in the Phase II MTD group. The corresponding entries for other adverse events report 6 of 6, 4 of 4, 5 of 5, 5 of 5, and 30 of 30. The registry also lists deaths of 6, 4, 1, 1, and 13 for those respective groups. These are descriptive group summaries; the record does not provide enough detail to infer event timing, causality, or whether an event met the primary DLT definition.

The serious-event terms listed include Death NOS at 100.0%, Diarrhea at 50.0%, Fatigue at 50.0%, Vascular disorders -Other at 25.0%, Heart failure at 25.0%, and Generalized muscle weakness at 25.0%. The denominator and calculation basis for these term percentages are not reported in the registry record. They should not be interpreted as rates in the whole study population or compared across dose groups without that information.

In general, adverse-event summaries are descriptive safety data and do not by themselves establish that a treatment caused an event. The serious-event categories should also not be equated with the endpoint’s narrower DLT criteria.

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

The registry record establishes that the study was designed to assess ruxolitinib dose escalation in CMML and then treat participants at the MTD. It defines the primary endpoint in terms of DLT frequency and specifies the toxicity criteria and a 17-week timeframe. It also records adverse-event summaries across four Phase I dose levels and a Phase II MTD group. These registry entries describe the study’s structure and the types of data recorded.

The record does not report the MTD result, dose-specific DLT counts, or results for the listed secondary outcomes. It therefore does not establish which dose was selected, how the primary endpoint was met, or what the observed response, survival, or AML transformation outcomes were. Without effect estimates and uncertainty measures, the precision of any efficacy estimate cannot be assessed.

The study is nonrandomized and single group, with no masking. Dose groups correspond to sequential stages rather than to randomized concurrent treatments. Consequently, the group summaries do not support a causal comparison of one dose against another or a comparison with an untreated or alternative-treatment control. Differences among the recorded groups may reflect study stage and the process of dose selection, as well as other factors that cannot be assessed from the record.

General statistical interpretation: a completed study is not necessarily a study with every result posted in the registry. A defined endpoint is not itself an endpoint result, and adverse-event counts do not substitute for outcome estimates. The posted information supports a description of the design, endpoint rule, and safety summaries, but not a conclusion about efficacy or the treatment’s overall benefit-risk balance. The registry record does not report enough information to make those assessments.

13. Why This Trial Matters Statistically

This study illustrates a statistical distinction between dose finding and treatment-effect evaluation. In the early stage, the central question is whether dose-related toxicity meets a prespecified rule. The primary endpoint is therefore a toxicity-defined dose, rather than a conventional comparison of response or survival between randomized groups. Its interpretation depends on the precise DLT definition, the assessment window, and the dose-level observations.

The sequential design also explains why dose-level summaries should not be treated as if they came from a randomized dose comparison. Participants were allocated nonrandomly through a rolling six Phase I design and then treated in a Phase II MTD group. The stages have different roles in the study, and the registry does not identify a concurrent control group. A statistical comparison across these groups would not, by itself, isolate the effect of dose.

The record is also a useful reminder that endpoint definitions and endpoint results are distinct. The MTD rule is described in detail, but the actual MTD and dose-specific DLT findings are not reported in the registry record. Likewise, the registry names secondary outcomes, yet their results are not reported in the registry record for this analysis. Reporting counts without analysis-population details, uncertainty estimates, and outcome definitions limits what can be inferred.

For biostatisticians and clinical researchers, the key issue is alignment: the analysis must match the endpoint and design. A dose-finding result requires the relevant DLT classification and dose-level evidence; comparative efficacy claims require a suitable comparison and reported outcome estimates. In this record, the design and endpoint can be explained, but the results needed to answer the primary and secondary clinical questions are not reported.

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 registry record does not report the observed MTD, the number of DLTs by dose, or the dose-level decisions used in escalation. That prevents direct assessment of the primary endpoint and prevents checking how the stated MTD rule was applied. The broad adverse-event summaries cannot fill this gap because serious adverse events and DLTs are not equivalent categories.

The nonrandomized, single-group design limits comparative interpretation. There is no randomized control group described, and Phase I dose levels are part of a sequential escalation rather than a randomized allocation. The Phase II group is a later stage at the MTD. Comparisons among these groups would therefore be vulnerable to differences associated with stage and dose selection, and no causal dose comparison can be established from the group counts alone.

The registry entries do not report detailed eligibility criteria, baseline characteristics, participant flow, analysis populations, or missing-data methods. They also do not report outcome estimates or uncertainty intervals for the primary endpoint and named secondary outcomes. For the adverse-event term percentages, the calculation denominator is not reported. These gaps constrain assessment of representativeness, precision, completeness, and the meaning of the safety summaries.

The registry lists the trial as completed, but completion status does not supply unreported results. Likewise, the enrollment entry does not explain the original sample-size rationale. The available record supports a description of the intended dose-finding framework and posted safety counts, but not a reconstruction of the full protocol, an evaluation of statistical power, or an efficacy conclusion.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Sequential Two-Stage Dose Escalation Study to Evaluate the Safety and Efficacy of Ruxolitinib — NCT01776723.
• Registry record last updated 2022-09-22; status last verified 2022-09.
• Results first posted 2020-03-12.
• 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

The registry describes a completed, nonrandomized Phase I/Phase II single-group study of oral ruxolitinib for CMML, with no masking. Phase I used a rolling six dose-escalation design starting at 10 mg/d with twice-a-day dosing; the adverse-event groups list levels of 10 mg, 20 mg, 30 mg, and 40 mg. Phase II treated participants at the MTD.

The primary endpoint was the MTD, defined by a drug-related DLT threshold during 17 weeks. The registry specifies the toxicity criteria but does not report the selected MTD or dose-specific DLT results. It lists secondary outcomes for AML transformation, overall survival, and response duration, but their results are not reported in the registry record. Adverse-event counts are recorded by group, while detailed analysis populations, missing-data methods, and inferential results are not reported.