JAK Inhibitor Before Donor Stem Cell Transplant in Treating Patients With Primary or Secondary Myelofibrosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for JAK Inhibitor Before Donor Stem Cell Transplant in Treating Patients With Primary or Secondary Myelofibrosis (NCT02251821), a na phase 2 study. The primary outcome is 2-year Overall Survival (OS) in Patients With Myelofibrosis (MF) Who Receive Treatment With a JAK Inhibitor Followed by an Allogeneic Transplant.

2. Clinical Question

3. Trial Design

This was a prospective phase II study of a treatment sequence for primary or secondary myelofibrosis: a JAK inhibitor before allogeneic stem cell transplantation. The registry lists a single treatment group and an allocation of not applicable. It does not describe random assignment or a concurrent control group. Masking is listed as none, so the record does not indicate that treatment or outcome assessment was masked.

The treatment group is described as receiving ruxolitinib and then undergoing myeloablative or reduced-intensity conditioning, followed by transplant and graft-versus-host disease prophylaxis. The listed interventions also include allogeneic hematopoietic stem cell transplantation, busulfan, cyclophosphamide, fludarabine phosphate, melphalan, methotrexate, mycophenolate mofetil, and laboratory biomarker analysis. The registry record does not provide further details about which conditioning or prophylaxis regimens each participant received.

Recorded enrollment was 61. The study start date was 2014-10-20, the primary completion date was 2022-12-28, and the study status is completed. These dates describe the registry record and do not supply the missing primary endpoint result.

A single-group design can describe outcomes among people who received the treatment sequence, but it cannot by itself establish how those outcomes compare with a different strategy. Differences from results in other studies could reflect differences in patients, care, follow-up, or outcome definitions rather than treatment. The registry record does not report a control group or a planned comparative analysis. It also does not report the protocol’s statistical plan or sample-size justification.

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.

Population: All transplanted patients

6. Primary Endpoint

The registry lists the primary outcome as 2-year Overall Survival (OS) in Patients With Myelofibrosis (MF) Who Receive Treatment With a JAK Inhibitor Followed by an Allogeneic Transplant, measured over 2 years.

The primary endpoint was 2-year overall survival in patients with myelofibrosis treated with a JAK inhibitor followed by an allogeneic transplant. Overall survival counts death from any cause, rather than death attributed to a particular disease or complication. The registry defines the time origin as the date of transplantation and the event as death. If death was not confirmed, the participant’s survival time was censored at the last date they were known to be alive.

Overall survival is a time-to-event measure: it uses both whether an event occurred and how long participants were followed before an event or censoring. The Kaplan-Meier method was specified to estimate the survival probability at 2 years. A 2-sided 95% confidence interval was also specified to express uncertainty around that estimate. In general, a confidence interval describes a range of values compatible with the data and method, rather than a guarantee that the true value lies within a particular interval.

The registry record does not report the estimated 2-year survival probability or its confidence interval. Therefore, the primary endpoint’s numerical result and its precision cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a time-to-event outcome. Unlike a simple proportion measured at a single visit, time-to-event analysis incorporates the timing of events and can use information from participants whose follow-up ends before an event is observed. In this study, the event was death from any cause, and the clock began at transplantation. The record says that survival time was censored at the last date a participant was known to be alive if death was not confirmed.

What does Kaplan-Meier estimation do?

In general, the Kaplan-Meier method estimates the probability of remaining event-free over time while accounting for censoring. At each observed event time, the estimate updates according to the participants still under observation and at risk immediately before that time. Censored participants contribute information up to their censoring time; they are not counted as having experienced the event at that point. The method relies on assumptions about censoring, including that the reasons for censoring do not make the remaining observed participants systematically unrepresentative of those censored, conditional on the analysis context. The registry record does not describe censoring patterns or diagnostics for this assumption.

The registry specifies a Kaplan-Meier estimate at the 2-year time point and a 2-sided 95% confidence interval. In general, the point estimate is the analysis’s estimated survival probability at that time. The confidence interval communicates statistical uncertainty around the estimate under the method’s assumptions. A wider interval indicates less precision than a narrower one. Because neither estimate nor interval is reported in the registry record, their values and precision cannot be evaluated.

Why is the time origin important?

The stated time origin is transplantation. That choice defines which period the primary endpoint summarizes: survival after the transplant date. It does not automatically include time before transplantation, such as the period during which a participant received ruxolitinib. A reader should distinguish the treatment sequence from the specific interval captured by the endpoint. The registry record does not provide additional endpoint timing details beyond the stated origin and 2-year timeframe.

What does the single-group design allow?

A single-group study can estimate outcomes observed in participants who received the treatment sequence. It does not separate the treatment’s effect from other influences on outcome, because there is no concurrent comparison group described. In general, a randomized comparison helps balance measured and unmeasured prognostic factors between groups; that design feature is not present in this record. The registry lists allocation as not applicable and masking as none. The record does not report an adjusted comparison with an external group.

The study is designated phase II. That designation identifies the recorded study phase, but it does not by itself establish the strength of evidence for a treatment effect or explain the statistical methods. The protocol’s statistical plan, sample-size justification, and any interim analyses are not reported in the registry record. No assumptions about those elements can be inferred from the phase label or the recorded enrollment.

How should adverse-event counts be understood?

Adverse-event summaries describe reported safety information, not necessarily events caused by treatment. The registry reports counts of participants at risk and affected for serious and other adverse events, plus selected serious-event terms as percentages. A participant-level count is not the same as an event count: one participant can experience more than one event, and a participant may contribute to more than one event category. The record does not provide the event-level detail needed to determine overlap, timing, duration, or attribution. These safety summaries also do not replace the time-to-event definition used for the primary endpoint.

In general, precision and interpretation depend on the amount and pattern of follow-up, the number and timing of events, and the assumptions used in analysis. The registry record does not report the primary survival estimate, confidence interval, censoring distribution, or the detailed analysis population. Consequently, the methods described establish how the endpoint was intended to be analyzed, but the record does not permit evaluation of the resulting numerical estimate or its robustness.

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("Treatment (Ruxolitinib, Transplant)")
n      <- c(61)
events <- c(48)
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  Treatment (Ruxolitinib, Transplant)  61  48  78.7  66.3  88.1  66.9  87.1  66.8  87.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists several secondary outcomes in addition to the primary overall-survival endpoint. They include acute graft-versus-host disease grade II-IV, chronic graft-versus-host disease, relapse at 1 year, non-relapse mortality, primary graft failure or rejection, secondary graft failure or poor graft function, and moderate or severe chronic graft-versus-host disease before 2 years post-transplant. Non-relapse mortality appears twice in the listed outcomes. The registry also records 10 outcome measures, but does not give corresponding results for the secondary outcomes in this record.

When a study evaluates multiple outcomes, testing many questions can increase the chance of at least one apparently notable result by chance. In general, a prespecified multiplicity strategy can address that issue, for example by defining a primary endpoint and specifying how secondary analyses will be interpreted or adjusted. The registry record does not report a multiplicity procedure or a hierarchy for interpreting secondary outcomes. It is therefore not possible to determine whether or how the study addressed multiplicity.

The record identifies the primary endpoint’s Kaplan-Meier method and confidence interval, but the full statistical analysis plan is not reported in the registry record. The record also does not report the analysis population, the amount of missing outcome information, or how missing data beyond censoring were handled. For time-to-event analysis, censoring is part of the stated endpoint definition; it is not equivalent to knowing that no event occurred. The number of censored participants and their follow-up durations are not reported in the registry record.

There are no analyses recorded in the listed analysis count. That does not establish that no analyses were conducted; it means the registry record does not provide analyses to interpret. The endpoint estimate, its confidence interval, secondary-outcome results, and a detailed account of missingness are not reported in the registry record.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: renal failure (3.3%), respiratory failure (3.3%), sepsis (1.6%), infections viral (1.6%), diffuse alveolar hemorrhage (1.6%).

The treatment group’s serious adverse-event summary lists 61 participants at risk and 7 affected. For other adverse events, it lists 61 at risk and 61 affected. The record also reports 14 deaths. These are separate registry summaries; the record does not establish that the adverse-event counts and deaths represent mutually exclusive groups or provide the timing and causes of death.

The listed serious adverse-event terms and percentages are renal failure, 3.3%; respiratory failure, 3.3%; sepsis, 1.6%; viral infections, 1.6%; and diffuse alveolar hemorrhage, 1.6%. The registry record does not give event counts for each term in this summary, explain whether participants could appear in multiple terms, or provide details about severity, duration, or treatment attribution. Percentages attached to selected terms should not be treated as a complete account of safety.

In general, adverse-event reporting describes events observed during a study and does not alone establish that treatment caused them. These figures should be read as registry-reported safety information for a single treatment group, not as a comparison against an untreated or alternative-treatment group. Further definitions and participant-level details are not reported in the registry record.

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

The study addresses a clinically relevant treatment sequence: ruxolitinib before allogeneic stem cell transplantation for people with primary or secondary myelofibrosis. Its primary endpoint is overall survival at 2 years after transplantation, defined using death from any cause and estimated by the Kaplan-Meier method. The registry record also identifies transplant-related and disease-related secondary outcomes and reports selected adverse-event information.

What the record does not provide is the numerical primary endpoint result. It does not report the 2-year survival estimate or its 95% confidence interval. It also does not provide results for the listed secondary outcomes. Therefore, the record cannot support a statement about the observed 2-year survival probability, its precision, or the direction and size of any association between the treatment sequence and those outcomes.

The single-group design further limits comparative interpretation. Observed outcomes in this group cannot establish what would have happened under another treatment strategy. Without a concurrent comparison group, differences from another population or study could reflect factors other than the treatment sequence. The registry record does not report a randomized comparison or a comparative estimate.

The adverse-event counts and listed serious-event percentages offer some descriptive safety information, but do not establish causation or provide a full account of events. The record does not report detailed event timing, attribution, overlap among categories, or causes of death. These limitations matter when interpreting the safety figures alongside survival outcomes.

Accordingly, the registry record is informative about the study question, design, endpoint definition, and some reported safety summaries. It is not sufficient to judge the primary survival result or to determine whether the treatment sequence performs better or worse than an alternative. Those conclusions require outcome estimates and comparative evidence that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable because it evaluates a complex treatment sequence while defining its primary endpoint specifically from the date of transplantation. The distinction between when treatment begins and when the survival clock starts is important: the endpoint summarizes post-transplant survival, rather than automatically measuring the whole period from initiation of ruxolitinib onward.

The registry describes a Kaplan-Meier analysis with a 2-sided 95% confidence interval. These methods are suited to time-to-event outcomes when participants may have different follow-up durations and some observations are censored. Their interpretation depends on the event definition, time origin, follow-up, and censoring. The registry provides the endpoint definition but not the estimate, interval, or censoring detail, leaving the main statistical result unavailable.

The single-group design also determines what can be learned. It can characterize outcomes among participants receiving the treatment sequence, but it cannot provide a direct randomized comparison with another strategy. That limitation is especially important when readers want to attribute outcomes to the pre-transplant treatment rather than to patient characteristics, transplant care, or other influences.

Finally, multiple secondary outcomes cover several aspects of transplant outcomes and safety. In general, interpreting many endpoints requires attention to prespecification and multiplicity. Those statistical details and the secondary results are not reported in the registry record. The study is therefore a useful example of why endpoint definitions, comparison structure, uncertainty estimates, and complete outcome reporting are all essential to statistical interpretation.

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 principal limitation for interpretation is that the registry record does not report the primary endpoint estimate or its 95% confidence interval. Without those values, neither the observed 2-year survival probability nor its statistical precision can be assessed. The record also does not report results for the listed secondary outcomes, despite identifying outcomes related to graft-versus-host disease, relapse, mortality, and graft function.

The design has no separate comparison group. Allocation is listed as not applicable, and the study is described as single group with no masking. Thus, the record does not support a direct estimate of how outcomes compare with another treatment strategy. It also does not describe adjustment for prognostic factors or an external comparison.

Several details that would help assess the analysis are not reported in the registry record: the full statistical plan, sample-size justification, interim analyses, analysis population, number and pattern of censored observations, and handling of missing information beyond the stated censoring rule. The registry does not report the duration or distribution of follow-up.

The safety information is also limited in detail. The record gives participant counts for serious and other adverse events and selected serious-event percentages, but does not report event timing, causes, attribution, duration, or overlap among event categories. The relation between the reported deaths and the primary endpoint is not specified. These limitations restrict both the clinical and statistical interpretation of the posted information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: JAK Inhibitor Before Donor Stem Cell Transplant in Treating Patients With Primary or Secondary Myelofibrosis — NCT02251821.
• Registry record last updated 2026-03-30; status last verified 2026-01.
• Results first posted 2024-03-05.
• 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

This completed phase II study enrolled 61 participants with primary or secondary myelofibrosis and evaluated ruxolitinib before allogeneic stem cell transplantation. It was a prospective single-group study, with allocation listed as not applicable and masking listed as none. The recorded study dates are 2014-10-20 for start and 2022-12-28 for primary completion.

The primary endpoint was 2-year overall survival from transplantation, defined as time to death from any cause and estimated using Kaplan-Meier with a 2-sided 95% confidence interval. The primary estimate and interval are not reported in the registry record. Secondary outcomes include transplant complications, relapse, non-relapse mortality, and graft failure, but their results are not included in the record details. The safety summary reports 7 affected among 61 at risk for serious adverse events, 61 affected among 61 at risk for other adverse events, and 14 deaths.