A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Axatilimab Monotherapy in Japanese Participants With Recurrent or Refractory Active Chronic Graft-Versus-Host Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Axatilimab Monotherapy in Japanese Participants With Recurrent or Refractory Active Chronic Graft-Versus-Host Disease (NCT06263478), a na phase 3 study. The primary outcome is Overall Response Rate (ORR) in the First 6 Treatment Cycles, as Defined by the 2014 NIH Consensus Development Project on Criteria for Clinical Trials in cGVHD.

2. Clinical Question

3. Trial Design

This is a Phase 3, open-label, multicenter, single-group study of axatilimab monotherapy in Japanese participants with recurrent or refractory active cGVHD after at least 2 lines of systemic therapy. The registry lists an enrollment of 21 and identifies the sponsor as Incyte Biosciences Japan GK. The study is recorded as active, not recruiting.

There is no randomized allocation or masking. Because all participants are assigned to one treatment group in the registry description, the design does not provide a concurrent control group for estimating how outcomes would have differed without axatilimab. Any response percentage would describe outcomes in the treated study population under the specified assessment rules; it would not, by itself, isolate a causal treatment effect from other influences.

The listed arm is axatilimab 0.3 mg/kg Q2W IV, with an arm description referring to the protocol-defined dose. The study is intended to evaluate efficacy, safety, and pharmacokinetics. The registry lists the start date as 2024-07-30 and the primary completion date as 2025-08-06. Those record entries do not establish that the study has completed or that results have been posted.

The primary endpoint assesses response during the first 6 treatment cycles, with the stated timeframe extending up to the end of Cycle 6 (up to 168 days). Secondary outcomes cover symptom improvement, response under the consensus criteria, response duration, organ-specific response, corticosteroid use, and adverse events. The registry lists 12 outcome measures and 0 analyses. The primary result 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.

Before assignment: This study was conducted at 14 study centers in Japan. Data collected through a cutoff date of 06 August 2025 have been included in this summary.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set: all participants who received at least 1 dose of study drug. Confidence intervals were calculated based on the exact method for binomial distributions.

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 Overall Response Rate (ORR) in the First 6 Treatment Cycles, as Defined by the 2014 NIH Consensus Development Project on Criteria for Clinical Trials in cGVHD, measured over up to the end of Cycle 6 (up to 168 days).

The primary endpoint is the overall response rate (ORR) during the first 6 treatment cycles, assessed under the 2014 NIH Consensus Development Project criteria for cGVHD. It is the percentage of participants with a physician-assessed complete response (CR) or partial response (PR). A participant counts as an objective responder if CR or PR is recorded at any timepoint up to the beginning of Cycle 7.

Under the endpoint definition, CR means resolution of all manifestations in each organ or site. PR means improvement in at least 1 organ or site without progression in any other organ or site. Thus, the endpoint combines two response categories and applies a stated assessment window. It does not describe how long a response persists; duration of response is listed separately as a secondary outcome for participants with a response in the first 6 treatment cycles.

ORR is used to express the proportion of the analysis population meeting a defined response threshold. In a single-group study, it describes observed responses among treated participants rather than a difference from a control group. The registry specifies a 95% confidence interval calculated by the exact method for binomial distributions. Neither the primary ORR estimate nor its interval is reported in the registry record, so the observed response rate and its precision cannot be characterized from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a proportion: the number of participants meeting the response definition relative to the relevant analysis population. In this trial, response means physician-assessed CR or PR under the 2014 NIH consensus criteria, observed at any timepoint up to the beginning of Cycle 7. The registry defines the Full Analysis Set as all participants who received at least 1 dose of study drug.

What does a confidence interval communicate?

In general, a confidence interval expresses the statistical uncertainty around an estimate. For a proportion, the interval reflects that the observed responder count is only one realization from a population-level process. A narrower interval indicates greater precision under the method's assumptions; a wider interval indicates less precision. It does not guarantee that the true value lies within the particular calculated interval, and it does not account automatically for every possible source of bias.

The registry specifies a 95% confidence interval using the exact method for binomial distributions. In general, exact binomial intervals are designed for proportion data and avoid relying on the normal approximation to the sampling distribution in the same way as a simple Wald interval. The method can be useful with modest sample sizes or proportions near the boundaries. The posted record does not give the endpoint estimate, responder count, analysis denominator, or interval limits, so there is no reported precision value to interpret.

What does the single-group design imply?

In general, a single-group study estimates outcomes observed among participants receiving the study intervention. It does not estimate a between-group contrast because there is no separate control arm in this design. Descriptive response results may be informative about the treated study population, but they cannot establish what the outcome difference would be against an alternative treatment or no study treatment. Open-label assessment also means treatment and study participation are not masked, although the registry record does not report how assessment bias was addressed.

The registry lists allocation as NA, masking as none, and the model as single group. These entries support describing the study as nonrandomized and open-label. They do not disclose a more detailed allocation procedure, a control condition, or an inferential comparison plan. Such details are not reported in the registry record.

How should the response window be read?

The endpoint counts response occurring through the beginning of Cycle 7, within the first 6 treatment cycles. This is a windowed binary outcome: each participant is classified according to whether the defined response was observed during that period. It is distinct from a time-to-event measure of when response occurred and from duration of response after response begins. The latter appears as a separate secondary outcome for participants responding in the first 6 treatment cycles.

In general, a fixed assessment window makes the endpoint easier to interpret as a proportion, but it limits the conclusion to that window and its assessment rules. Participants who respond after the window would not meet this endpoint definition based on the stated timeframe. The record does not report how assessments were scheduled, how missed assessments were treated, or whether response adjudication was independent.

What does the sample-size illustration mean?

The posted planning information is described as an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes an effect to detect as a stated fraction of the observed effect. The assumptions are not the design of this single-group trial: the trial itself has no two-arm randomized comparison. The illustration is planning information, not observed power and not a trial result.

In general, planning calculations depend on the effect size, variability or event rate, allocation, statistical test, and chosen error rates. They describe what a hypothetical study might require under stated assumptions; they do not show that the current study had a particular probability of detecting an effect. The record does not report the trial's own sample-size justification, any interim analyses, or a detailed statistical analysis plan. The illustration should therefore not be treated as evidence about the adequacy of the completed or ongoing study.

Why are safety summaries different?

Safety outcomes are counts of participants with specified events, rather than the primary efficacy proportion. Serious adverse events and other treatment-emergent events have distinct definitions and can have different reporting rules. In general, safety summaries describe observed events over the recorded observation period; interpretation depends on event definitions, exposure time, and the population evaluated. The registry record lists participant counts and selected serious-event terms but does not provide a comparative safety analysis.

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("Axatilimab 0.3 mg/kg IV Q2W")
n      <- c(21)
events <- c(15)
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  Axatilimab 0.3 mg/kg IV Q2W  21  15  71.4  47.8  88.7  50.0  86.2  49.8  86.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures, including the primary ORR and secondary outcomes for symptom improvement, consensus-defined response, response duration, organ-specific response, corticosteroid use, and adverse events. It lists 0 analyses. An outcome list identifies measures of interest, but it does not by itself describe which statistical hypotheses were tested, whether tests were confirmatory, or how inference across multiple outcomes was handled.

A multiplicity strategy, such as a hierarchy, adjustment procedure, or distinction between confirmatory and exploratory outcomes, is not reported in the registry record. Without that information, it is not possible to determine whether or how the interpretation of multiple statistical tests was controlled. The absence of listed analyses also means there are no posted analysis results from which to assess a testing sequence.

The primary analysis population is defined as participants who received at least 1 dose of study drug. The registry specifies an exact binomial confidence interval for the primary endpoint. It does not report the analyzed population count, responder count, or primary result. Missing-data methods, handling of participants without an evaluable response, and rules for incomplete follow-up are not reported in the registry record.

In general, missing outcome data can affect a proportion if participants without an assessment are handled differently from those with observed assessments. The direction and size of any effect depend on why data are missing and on the analysis rules; neither can be inferred from the record. The endpoint's treatment-receipt population definition should not be mistaken for a complete account of how missing observations were managed.

The registry also does not report the trial's detailed statistical analysis plan, interim analyses, or sample-size justification. The planning illustration is not a substitute for those details and does not establish the analysis strategy used for the trial.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: appendicitis (4.8%), asthma (4.8%), covid-19 (4.8%), cystitis viral (4.8%), dehydration (4.8%).

The registry's safety listing is for the axatilimab 0.3 mg/kg Q2W IV group. It records 21 at risk in the serious-event grouping and 7 affected. A separate adverse-event grouping lists 21 at risk and 19 affected. The record also lists zero deaths. These are participant counts, not a comparison between treatment arms, because the study is single-group.

The serious-event terms listed are Appendicitis, Asthma, COVID-19, Cystitis viral, Dehydration, and Large intestine polyp, each with a frequency of 4.8%. The record presents these as selected serious-event terms. It does not provide enough information in this listing to infer severity beyond the serious-event classification, timing, duration, relatedness to treatment, or clinical outcome for each event.

In general, adverse-event counts depend on the event definitions, observation period, and safety population. The registry record does not report exposure-adjusted event rates or a control-group rate. Therefore, the figures describe the listed safety observations in this study and do not support a comparative risk estimate. The primary efficacy result is not reported in the registry record, and these safety entries do not resolve that absence.

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

The record describes a study designed to assess axatilimab monotherapy in Japanese participants with recurrent or refractory active cGVHD after at least 2 lines of systemic therapy. Its primary endpoint has a defined clinical response rule and a specified assessment window. The registry also specifies an exact binomial method for the primary 95% confidence interval.

However, the record does not report the primary ORR estimate, responder count, analysis denominator, or confidence interval. It therefore does not establish what response proportion was observed or how precise that estimate was. The endpoint definition and study objective are not substitutes for outcome data.

If a response percentage were reported, it would describe participants in the Full Analysis Set who had a physician-assessed CR or PR during the specified window. Because the study is open-label and single-group, that percentage would not constitute a randomized comparison or a direct estimate of a treatment effect relative to a control. No alternative treatment or concurrent control group is listed.

The outcome is limited to response observed through the beginning of Cycle 7. It does not, by definition, indicate how long a response lasts, whether it persists after that window, or what happens beyond it. The registry lists duration of response separately, but its result is not reported in the registry record. Other listed secondary outcomes likewise cannot be interpreted without their results.

The safety entries report event counts and selected serious-event terms, including zero deaths in the listing. They provide descriptive information but no comparative safety estimate. Overall, the registry record outlines the question, endpoint, analysis population, and some safety counts, while leaving the primary efficacy result and key analysis details unreported.

14. Why This Trial Matters Statistically

This study addresses a defined population: Japanese participants with recurrent or refractory active cGVHD after at least 2 lines of systemic therapy. Its single-group Phase 3 design provides a setting in which to describe response, safety, and pharmacokinetics for axatilimab monotherapy in that population. The specific eligibility and treatment context matter when considering how applicable any eventual findings may be to people outside the study population.

Statistically, the endpoint is a proportion with explicit clinical criteria and a defined response window. That structure makes clear what counts as response and when it must be observed. The specified exact binomial confidence interval would provide information about precision around the response estimate, once the estimate and analysis denominator are reported.

The study also illustrates the distinction between describing outcomes and estimating comparative effects. With one open-label group and no control arm, a response proportion would be a within-study description. It would not, on its own, measure a difference against another treatment or address how outcomes would have differed under another condition.

The registry lists secondary measures spanning symptoms, organ response, corticosteroid use, response duration, and adverse events. Such outcomes can describe different aspects of the study question, but their interpretation depends on reported definitions, analysis methods, and results. The current registry record lists the measures but does not report analyses or the primary result. Its statistical importance therefore lies in the design and endpoint framework that are documented, alongside the limits created by the absence of posted efficacy estimates.

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 primary limitation for interpreting efficacy is that the registry record does not report the primary ORR estimate or its 95% confidence interval. It also does not report the responder count or the number included in the primary analysis. Without these values, neither response magnitude nor precision can be assessed.

The study is open-label and single-group, with no randomized control arm. A response outcome is physician-assessed, so the design does not provide a masked, concurrent comparison for contextualizing the observed response. The record does not report whether any independent review or other procedure was used to reduce assessment bias.

The endpoint is limited to response observed up to the beginning of Cycle 7. It does not capture response after that period under its stated definition, and it does not measure response duration. Duration of response is listed separately, but its result is not reported in the registry record.

Important analysis details are also absent: missing-data handling, treatment of participants without evaluable response assessments, multiplicity procedures, interim analyses, and the detailed statistical analysis plan are not reported in the registry record. The record lists 12 outcome measures and 0 analyses, limiting interpretation of the broader set of outcomes.

The safety listing gives counts and selected serious-event terms but does not provide a control-group comparison or exposure-adjusted rates. The listed enrollment of 21 should not be treated as the primary analysis denominator, which is defined by receipt of at least 1 dose and is not numerically reported. These limitations mean that the record supports a description of the study framework, not a complete assessment of efficacy or comparative safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study to Evaluate the Efficacy, Safety, and Pharmacokinetics of Axatilimab Monotherapy in Japanese Participants With Recurrent or Refractory Active Chronic Graft-Versus-Host Disease — NCT06263478.
• Registry record last updated 2026-10-05; status last verified 2026-10.
• Results first posted 2026-10-05.
• 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

The registry describes a Phase 3, open-label, multicenter, single-group study of axatilimab monotherapy in Japanese participants with recurrent or refractory active cGVHD after at least 2 lines of systemic therapy. The listed regimen is axatilimab 0.3 mg/kg Q2W IV. Enrollment is listed as 21, and study status is active, not recruiting.

The primary endpoint is the percentage with physician-assessed CR or PR during the first 6 treatment cycles under the 2014 NIH consensus criteria. The Full Analysis Set includes participants who received at least 1 dose, and the specified 95% confidence interval method is exact for binomial distributions. The primary response estimate and confidence interval are not reported in the registry record.

The registry lists 12 outcome measures and 0 analyses. Safety entries include the listed serious-event and other adverse-event counts, selected serious-event terms, and zero deaths. Missing-data methods, multiplicity procedures, and a detailed statistical analysis plan are not reported in the registry record.