Maraviroc as GVHD Prophylaxis in Transplant Recipients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Maraviroc as GVHD Prophylaxis in Transplant Recipients (NCT02167451), a na phase 1, phase 2 study. The primary outcome is Feasibility of Maraviroc.

2. Clinical Question

The registry’s brief summary frames the intended purpose as determining whether adding maraviroc will reduce graft-versus-host disease after transplant. However, the stated primary outcome is feasibility, not a comparative measure of disease incidence. That distinction matters: a feasibility outcome asks whether an intervention can be delivered in the intended setting, while a treatment-effect question requires an outcome comparison that can distinguish the intervention’s effect from other explanations.

The study enrolled 31 participants and is listed as phase 1 and phase 2. Its record includes secondary outcomes for overall survival, graft failure, primary disease relapse, toxicities, infectious complications, and times to neutrophil and platelet engraftment. Those listed outcomes describe what the study intended to track; they do not establish that results or statistical analyses for each outcome were reported. The registry record does not report a primary endpoint result or an analysis comparing maraviroc with a control group.

3. Trial Design

This is a single-group phase 1/phase 2 study of maraviroc in pediatric and adult stem cell transplant recipients. The registry reports an enrollment of 31 and lists the study status as terminated. The recorded start is 2014-07 and the primary completion is 2018-09. The reason for termination is not reported in the registry record.

The study has no randomized allocation and no masking. The registry identifies one maraviroc group, with maraviroc used alongside routine standard graft-versus-host disease prophylaxis. There is no separate concurrent control arm described. Consequently, the design does not provide a like-for-like comparison between recipients assigned to maraviroc and recipients assigned to a different prophylaxis strategy. Descriptive observations in this group can characterize what was recorded among its participants, but cannot by themselves isolate the effect of adding maraviroc.

The intervention description says administration begins on day -3 and ends on day +30 after stem cell transplant, for a total of 34 days. It is described as twice daily by mouth or through an enteral tube. Dosing is based on body surface area, but the registry’s available arm description is incomplete after “starting w”; the exact dosing details are not reported in the registry record. The record does not give further operational details about treatment adherence or how feasibility was defined as a success.

The primary outcome is a participant count through day +100 and is described as the ability to administer the twice-daily oral drug in children and adults undergoing transplant in addition to routine prophylaxis. The listed secondary outcomes cover survival, graft failure, relapse, toxicities, infections, and engraftment timing. The record lists 12 outcome measures overall, but does not report analysis results for them. A single-group design may be useful for documenting delivery and describing outcomes in the enrolled group; it is not a randomized design for estimating a treatment contrast.

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:

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: not different

6. Primary Endpoint

The registry lists the primary outcome as Feasibility of Maraviroc, measured over Up to day +100.

The primary endpoint is titled “Feasibility of Maraviroc.” It is recorded as a count of participants, with a timeframe of up to day +100. Its description focuses on whether twice-daily oral maraviroc can be administered to children and adults undergoing stem cell transplant while they also receive routine standard graft-versus-host disease prophylaxis. The intervention description permits oral or enteral-tube administration.

Feasibility is used to address whether an intervention can be delivered in the clinical setting and population for which it is being considered. As a general statistical concept, a feasibility endpoint is different from an efficacy endpoint: the former concerns delivery or implementation, whereas the latter concerns whether outcomes differ under alternative treatment strategies. A count can describe how many participants meet a stated criterion, but interpretation requires knowing what counts as successful administration, how incomplete administration is handled, and what denominator or analysis population is used.

The registry record does not report a numerical primary endpoint result, a success threshold, or a detailed rule for classifying participants as feasible or not feasible. It also does not report an inferential analysis of the primary endpoint. Therefore, the registered description establishes the intended topic and observation timeframe, but not the observed feasibility rate or whether a predefined target was reached. No conclusion about the primary endpoint can be drawn from the outcome description alone.

The stated purpose in the brief summary also refers to reducing graft-versus-host disease. That is not the registered primary endpoint. The record lists other clinical outcomes, but a listed outcome is not itself evidence of a result. Keeping the feasibility endpoint separate from disease and safety outcomes prevents a delivery measure from being misread as a comparative estimate of clinical benefit.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Methods determine which question a statistic answers and how much uncertainty should accompany it. In this registry record, the primary outcome is a participant count, and the study is single-group. The record lists no analyses. The explanations below describe general statistical principles relevant to interpreting these design features; they do not imply that a particular unreported method was used in this study.

What does a participant count measure?

A count records how many people meet a specified condition. For a feasibility outcome, that condition needs a clear operational definition: for example, the protocol would need to specify what level of administration qualifies as feasible and how interruptions or missing follow-up are treated. The registry describes the broad ability to administer twice-daily maraviroc, but does not report a detailed success rule or the observed count. A count without a stated denominator and classification rule can be difficult to interpret as a measure of feasibility.

Counts are descriptive. If a study reports a count and a denominator, readers can understand the number of participants represented, but a count alone does not estimate a causal treatment effect. An inferential analysis may quantify uncertainty around an estimated rate or compare outcomes across groups, but the registry record does not report such a primary endpoint analysis. No confidence interval or test result for feasibility is reported in the registry record.

What does the single-group design allow?

A single-group study follows participants receiving the intervention, rather than assigning participants to distinct intervention and control groups. It can describe treatment delivery and observed outcomes in the enrolled group. It cannot directly estimate the contrast between outcomes under maraviroc and outcomes under a separate alternative strategy, because no concurrent control group is described. General changes in clinical practice, differences in patient characteristics, and the course of transplantation can also influence observed outcomes. Without a comparison design and appropriate analysis, these influences cannot be separated from an intervention effect.

Random allocation is one way to support a fair comparison, because it aims to balance factors that could influence outcomes across treatment groups. This study is not described as randomized and has no separate control arm. That does not erase the value of descriptive observations, but it limits claims about what caused them. The absent masking similarly means the record does not describe blinded assessment; the potential influence of knowledge of treatment depends on the outcome and how it is assessed. The registry does not report further assessment procedures.

How should uncertainty be understood?

In general, a confidence interval gives a range of values compatible with the observed data under a specified statistical model and procedure. It communicates precision as well as the estimate’s direction and scale. A narrow interval indicates greater precision under those assumptions, while a wide interval indicates greater uncertainty. A confidence interval is not a guarantee that the true value lies inside its particular bounds, and it does not correct design limitations such as the lack of a control group. No confidence interval for the primary outcome is reported in the registry record.

A significance test addresses compatibility between data and a null hypothesis under an analysis plan. A p-value does not measure the size or clinical importance of an effect, nor does it establish causation. The record reports no analyses, so no p-value or test-based conclusion for the primary endpoint is available. The registry also does not report an analysis plan that would establish which tests, models, or uncertainty measures were intended.

Why do planning assumptions matter?

Sample-size planning asks how many participants a future or planned study might need under specified assumptions about the outcome, effect to detect, significance level, allocation, and statistical method. Such calculations are conditional illustrations: changing an assumption can change the resulting planning requirement. They are not observed outcomes and do not show how much power a completed study actually had. In particular, sample-size calculations based on an observed effect should not be called observed power.

The described planning assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is expressed as a fraction of the observed effect. For time-to-event outcomes, the described calculation concerns a total number of events, while other calculations concern participants per arm. These are general planning conventions in the stated illustration, not evidence that this study used two arms or those design assumptions. The actual registry design is single-group, and no treatment-effect estimate for the primary outcome is reported. The registry does not report its own sample-size justification, so the planning illustration should not be treated as the trial’s protocol rationale.

Why can over-dispersion matter?

As a general concept, over-dispersion occurs when observed variability exceeds what a statistical model assumes. If a count model underestimates variability, its uncertainty estimates can be too small and its intervals or tests can appear more precise than warranted. Whether over-dispersion is relevant depends on the outcome and model; it cannot be diagnosed from an outcome label alone. The registry record does not report a count model, a dispersion assessment, or an analysis of the feasibility count, so no claim can be made about over-dispersion in this study.

Likewise, time-to-event outcomes such as overall survival or time to engraftment require methods that account for follow-up duration and censoring. Censoring occurs when the event time is not observed for a participant within the available follow-up, and its handling can affect interpretation. These are general considerations for the listed outcomes, not methods documented for this record. The registry lists those outcomes but provides no analysis results or method details for them.

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("Maraviroc")
n      <- c(31)
events <- c(23)
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  Maraviroc  31  23  74.2  55.4  88.1  56.8  86.3  56.6  86.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and includes several secondary outcomes, among them overall survival, graft failure, primary disease relapse, toxicities, infectious complications, and time to neutrophil and platelet engraftment. When a study evaluates multiple outcomes or makes multiple statistical comparisons, the chance of at least one apparently notable result can increase. General approaches to multiplicity include prespecifying a primary hypothesis, controlling a family-wise error rate, or treating secondary analyses as exploratory. Which approach is appropriate depends on the study aims and analysis plan.

The registry record does not report multiplicity procedures, a hierarchy for interpreting outcomes, or statistical analyses. It therefore does not establish whether any adjustment was planned or applied. No conclusion about a multiplicity-adjusted result is available. The primary outcome is identified as feasibility, but its success criterion and result are not reported.

Missing-data methods are also not reported in the registry record. The record does not describe how missing primary outcome information, incomplete drug administration, loss to follow-up, or unavailable secondary outcome measurements were handled. These details matter because a participant with an unknown outcome may not be equivalent to a participant who did not meet a feasibility criterion. Without a reported rule, the direction or effect of missingness cannot be assessed.

Analysis populations are not reported in the registry record. In general, an analysis population defines which participants contribute to a particular estimate, such as all enrolled participants or only those with outcome data. Different choices can yield different summaries, especially if participation or follow-up is incomplete. The enrollment count of 31 does not establish the denominator used for the primary endpoint or any secondary outcome. No denominator beyond the safety at-risk counts is specified for the primary outcome.

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: blood bilirubin- increased (16.1%), sinusoidal obstructive syndrome (9.7%), infection-enterococcus bacteremia (9.7%), infection- staphylococcus aureus bacteremia (9.7%), infection- disseminated adenoviremia (6.5%).

For the maraviroc group, the registry records 31 participants at risk for serious adverse events, of whom 11 were affected. For other adverse events, 31 were at risk and 16 were affected. Four deaths are listed. These are descriptive participant figures in the study group; they are not comparative estimates against a control group. The registry record does not establish that the events or deaths were caused by maraviroc.

The registry also lists serious adverse event terms and percentages: Blood Bilirubin- Increased, 16.1%; Sinusoidal Obstructive Syndrome, 9.7%; Infection-Enterococcus Bacteremia, 9.7%; Infection- Staphylococcus Aureus Bacteremia, 9.7%; Infection- Disseminated Adenoviremia, 6.5%; and Immune System Other (Engraftment Syndrome), 6.5%. These are the reported category labels and percentages. The record does not clarify whether categories overlap, whether figures count people or events, or how the terms were grouped beyond the labels shown.

As a general distinction, a serious adverse event is classified by seriousness criteria and is not simply another name for an event’s intensity. The figures should not be read as rates of treatment-caused harm, and they do not show how event risks compare with another regimen. Attribution, timing details, and a comparative safety analysis are not reported in the registry record. The figures describe what the registry lists for this group, with those limits.

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

The registry record describes a study of maraviroc added to routine graft-versus-host disease prophylaxis in stem cell transplant recipients. It identifies feasibility as the primary outcome and sets a timeframe of up to day +100. The record reports enrollment of 31 participants, but does not report the primary outcome value or a rule for deciding whether administration was feasible. It therefore does not establish how many participants met a feasibility criterion.

The brief summary describes an aim of reducing graft-versus-host disease. That aim should not be confused with a reported treatment effect. This study is single-group, with no randomized comparator arm. An observed outcome in the maraviroc group, even if reported, would not by itself show what the outcome would have been under a different prophylaxis strategy. The registry record reports no analysis results that would support a causal comparison.

The safety counts and listed event categories provide descriptive information about events recorded among participants in the maraviroc group. They do not show that the intervention caused or prevented any event. There is no control group for estimating a comparative risk, and the record does not report attribution details or an analysis of safety outcomes. The number of deaths is a reported group figure, not evidence about their cause.

The status is terminated and the primary completion is recorded as 2018-09, but the reason for termination is not reported in the registry record. That status cannot be used to infer why the study ended or whether the intervention met its feasibility objective. Nor does it establish whether all planned outcomes were collected or analyzed.

Planning calculations are hypothetical illustrations based on stated assumptions. They are not observations from participants, do not establish observed power, and do not overcome the single-group design. In sum, the registry record documents the intended feasibility question, study setup, enrollment, and selected safety information. It does not provide the primary result, the outcome analyses, or a controlled estimate of the effect of maraviroc on graft-versus-host disease.

14. Why This Trial Matters Statistically

This trial is statistically useful to examine because its stated clinical motivation and its registered primary endpoint address different questions. The brief summary focuses on reducing graft-versus-host disease, while the primary endpoint concerns feasibility of administering maraviroc. A careful reading keeps implementation evidence distinct from evidence of treatment effect. Both questions can matter in clinical research, but answering one does not automatically answer the other.

The single-group design also illustrates the difference between describing outcomes and estimating a contrast. The registry records one maraviroc group and no randomized control. Counts and event categories can characterize what was recorded among participants, but cannot establish what would have occurred under another strategy. This is a central issue of interpretation rather than a technical footnote: statistical precision cannot create a comparison that the design did not include.

The record’s missing primary result and lack of reported analyses underscore why registration details alone are not equivalent to an outcome report. The endpoint title, timeframe, and description indicate the intended measurement, but readers also need the observed result, denominator, operational success definition, and analysis methods to assess it. Those details are not reported in the registry record.

The safety information gives concrete descriptive counts, while also demonstrating why event classification and attribution must be kept separate. A number of participants affected by an event is not, by itself, a causal estimate. Without comparative data and appropriate analytic detail, it cannot distinguish intervention-related risk from background events in the transplant setting.

Finally, hypothetical sample-size illustrations should not be mistaken for evidence that a study had adequate power or that an effect was observed. The stated planning assumptions describe a two-arm allocation, while the actual study is single-group. Recognizing that mismatch prevents planning arithmetic from being misread as an analysis of this trial. These distinctions make the record informative about design and reporting limits, while setting appropriate boundaries on what can be concluded statistically.

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 the single-group design. With no randomized comparison group, the study cannot estimate a between-group treatment effect for graft-versus-host disease, feasibility, or safety. The registry also lists no masking. These design features mean that descriptive findings, if reported, would not establish that maraviroc caused an outcome or that outcomes differed from those under another strategy.

The primary endpoint is described broadly as the ability to administer twice-daily oral maraviroc, but the registry record does not report a detailed operational definition, success threshold, or observed result. It does not state the analysis denominator or explain how incomplete treatment administration would be classified. Although the intervention description allows enteral-tube administration, the primary endpoint wording emphasizes oral administration; the record does not explain how administration routes are handled in the endpoint definition.

The arm description is incomplete after the phrase “starting w,” so the exact dosing details are not reported in the registry record. The reason for the terminated status is also not reported. No sample-size justification, statistical analysis plan, analysis populations, multiplicity method, or missing-data approach is reported. The registry lists 12 outcome measures but records no analyses, limiting interpretation of both the primary endpoint and secondary outcomes.

The serious and other adverse-event counts are descriptive. The registry does not report a control group, causal attribution, or enough detail to determine whether the listed serious-event percentages represent people or events, or whether categories overlap. These limitations do not negate the recorded counts; they define what the counts can support. Further protocol and results information is not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Maraviroc as GVHD Prophylaxis in Transplant Recipients — NCT02167451.
• Registry record last updated 2020-03-10; status last verified 2020-02.
• Results first posted 2020-03-10.
• 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.

19. Record Summary

The record concerns maraviroc as graft-versus-host disease prophylaxis in pediatric and adult stem cell transplant recipients. It is listed as phase 1 and phase 2, single-group, unmasked, and nonrandomized, with enrollment of 31. The recorded start is 2014-07, primary completion is 2018-09, and status is terminated.

Maraviroc is described as twice-daily oral or enteral-tube administration, beginning on day -3 and ending on day +30 after transplant. The primary outcome is feasibility, measured as a participant count through day +100. Secondary outcomes include survival, graft failure, relapse, toxicities, infections, and engraftment timing.

The registry reports no analyses and does not report the primary endpoint result, its success threshold, or the reason for termination. Serious adverse events affected 11 of 31 participants at risk; other adverse events affected 16 of 31 at risk, and 4 deaths are listed. These safety figures are descriptive and do not establish causation or comparative risk.