Effects of JNJ-53718678 in Adult and Adolescent Participants Who Had a Hematopoietic Stem Cell Transplantation and Who Are Infected With Respiratory Syncytial Virus (RSV): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of JNJ-53718678 in Adult and Adolescent Participants Who Had a Hematopoietic Stem Cell Transplantation and Who Are Infected With Respiratory Syncytial Virus (RSV) (NCT04056611), a randomized phase 2 study. The primary outcome is Percentage of Participants Who Developed Respiratory Syncytial Virus (RSV) Lower Respiratory Tract Infection (LRTI).

2. Clinical Question

The clinical question concerns progression from RSV infection of the upper respiratory tract to LRTI among transplant recipients. This population and outcome are specified in the registry record; no conclusions about treatment effects can be drawn from the record's enrollment information alone. The listed secondary outcomes include RSV-associated lower respiratory tract complications, safety findings, respiratory failure, and mortality. Their planned inclusion does not establish that evaluable data were collected or analyzed. For the primary outcome, the record does not report participant counts by group, an effect estimate, a confidence interval, or a test of statistical significance. It also does not report a primary comparison in the posted results. The study's clinical question is therefore clear, but the posted information does not answer it with an estimate of the difference between JNJ-53718678 and placebo.

3. Trial Design

The registry describes a Phase 2, randomized, double-blind, parallel-group, placebo-controlled study. It was intended to evaluate clinical outcomes, antiviral activity, safety, tolerability, pharmacokinetics, and pharmacokinetics/pharmacodynamics of JNJ-53718678 in adult and adolescent hematopoietic stem cell transplant recipients with RSV infection of the upper respiratory tract. The sponsor is Janssen Sciences Ireland UC. The registry lists a start date of 2019-12-26 and a primary completion date of 2022-02-04. The overall status is terminated, and enrollment is reported as 3.

The intervention list includes JNJ-53718678 250 mg, JNJ-53718678 125 mg, and placebo. The arm descriptions distinguish adult and adolescent cohorts and refer to dosing conditions involving CYP3A4 inhibitors, but the descriptions are cut off. The complete treatment schedules and the allocation of participants to each treatment group are not reported in the registry record. Although the design is described as randomized and double-blind, the specific randomization method and details of who was masked are not reported in the registry record.

The primary outcome was the percentage of participants who developed RSV LRTI up to Day 28. The registry also lists 28 outcome measures and several secondary outcomes covering respiratory complications, adverse events, laboratory, ECG and vital-sign findings, respiratory failure, and death. The listed outcomes describe the study's intended scope, but do not establish which outcomes had analyzable observations. The registry record contains no analysis entries. It does not report why the study was terminated, how many participants were assigned to each group, or whether the enrollment reflects all participants who began treatment. Those details should not be inferred from the design description or the overall enrollment count.

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: Participants were randomized to receive either rilematovir or placebo. The dose was dependent upon coadministration without/with CYP3A4 inhibitors or posaconazole. Due to the limited participants randomized and due to chance, no participants were randomized to placebo.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Efficacy analysis set included all participants who were randomized, treated (took at least 1 dose), and had a RSV infection confirmed by central laboratory analysis, excluding participants infected with a co-pathogen at baseline not identified during screening, analyzed as randomized.

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 Percentage of Participants Who Developed Respiratory Syncytial Virus (RSV) Lower Respiratory Tract Infection (LRTI), measured over Up to Day 28.

The primary endpoint is the percentage of participants who developed RSV lower respiratory tract infection (LRTI) up to Day 28. It is a binary outcome at the participant level: each participant is classified according to whether the endpoint occurred during the stated period. The registry defines LRTI using clinical findings, RSV testing, and imaging criteria. These include new lower respiratory signs or symptoms with a positive RSV test from a lower respiratory sample and a new chest image finding consistent with LRTI; a positive lower respiratory sample alone; or a positive upper respiratory sample within the specified timing relative to a new image finding consistent with RSV LRTI, as determined by the Endpoint Adjudication Committee.

Such an endpoint is used to represent clinically identified progression to lower respiratory disease rather than infection of the upper respiratory tract alone. The definition combines evidence sources because no single observation in the listed criteria is required in every pathway. Adjudication is intended to apply the endpoint definition consistently, although details of adjudication procedures beyond the role of the Endpoint Adjudication Committee are not reported in the registry record.

The registry identifies the efficacy analysis population as randomized participants who took at least 1 dose and had centrally confirmed RSV infection, with a specified exclusion for a baseline co-pathogen missed during screening. Results for this endpoint are not reported in the registry record. In particular, there are no reported group-specific event percentages, participant denominators, effect estimates, confidence intervals, or statistical tests. The endpoint definition therefore clarifies what the study intended to measure, but the posted record does not establish how often it occurred or how groups compared.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods describe how observations are converted into estimates and how uncertainty is assessed. In this study, the primary endpoint is expressed as a percentage of participants with an event. In general, a binary endpoint classifies each participant as having or not having the event under a stated definition and time period. A group percentage is interpretable alongside the number of participants assessed in that group; without the denominator, the precision and context of the percentage are unclear. The registry record does not report primary endpoint percentages or denominators by treatment group.

What does a confidence interval communicate?

General explanation: a confidence interval gives a range of values compatible with the observed data under a specified statistical procedure. Its width reflects precision: less information or more variability generally leads to a wider interval. It is not a guarantee that the true effect lies in the interval, nor does it replace examination of the estimate itself. The registry record does not report a confidence interval for the primary endpoint, so the precision of any treatment comparison cannot be evaluated from the posted results.

Why does the analysis population matter?

The registry defines an efficacy analysis population using randomized participants who took at least 1 dose and had RSV confirmed by central laboratory analysis, with an exclusion for a baseline co-pathogen that was not identified during screening. It also says these participants were analyzed as randomized. In general, analysis-population rules determine who contributes to an estimate and how participants are assigned to groups for analysis. Exclusions can affect how well an estimate reflects the randomized comparison, particularly if the excluded participants differ from those retained. The record does not report participant-level disposition, numbers excluded, or outcome availability, so the implications of the stated criteria cannot be assessed.

What can randomization and masking contribute?

General explanation: random allocation is intended to make treatment groups comparable on average with respect to factors measured and not measured at baseline. Masking can reduce the influence of treatment knowledge on care, outcome assessment, or reporting. These design features do not ensure balance in every realized trial, and they do not eliminate uncertainty. The registry identifies the study as randomized and double-blind, but does not report the specific allocation method or the detailed masking procedures. With enrollment of 3 and no posted group-level outcome data, the record does not allow examination of baseline balance or the practical success of masking.

How should significance testing be understood?

General explanation: a significance test evaluates how compatible the observed data are with a stated null hypothesis under a statistical model. A p-value is not the probability that the null hypothesis is true, and a threshold-based result does not measure clinical importance. Interpretation is strongest when estimates, uncertainty intervals, analysis choices, and the context of all planned outcomes are considered together. No primary-outcome p-value, statistical test, or treatment-effect estimate is reported in the registry record. The registry lists no analysis entries, so no inferential result can be described.

What does planning for power mean?

General explanation: sample-size planning uses assumptions about the event rate, effect to detect, variability, allocation, significance level, and desired power to illustrate the amount of information a study might need. Such planning values are not results from enrolled participants. They are not observed power and cannot establish whether a study succeeded or failed to detect an effect. The record does not report a study-specific sample-size justification or the assumptions used by the sponsor. A planning illustration based on an observed effect would also not substitute for a prospective design justification or a reported analysis. The registry record does not provide primary comparison results from which a treatment effect can be assessed.

For a binary endpoint, the event count and the number assessed in each group inform an estimated percentage. A comparison can be expressed in different ways, but each needs the underlying group data and an appropriate uncertainty measure. The available record does not report these components for the primary endpoint. No alternative adjusted model, covariate set, handling of repeated observations, or missing-data procedure is reported in the registry record. These methods should not be assumed from the study's randomized design or from the endpoint description.

The registry does list safety outcomes and multiple secondary outcomes. General explanation: testing multiple outcomes raises a multiplicity issue because, as the number of tests increases, the chance of at least one apparently unusual result can increase if no adjustment or hierarchy is used. A plan may address this through prespecified ordering or statistical adjustment, but the approach must be reported to evaluate it. The statistical plan for the listed outcomes is not reported in the registry record. Since analysis entries are absent, there are no reported secondary-outcome tests or estimates to interpret.

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("JNJ-53718678")
n      <- c(3)
events <- c(0)
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  JNJ-53718678  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 28 outcome measures, including the primary percentage of participants who developed RSV LRTI and secondary outcomes involving respiratory complications, adverse events, laboratory, ECG and vital-sign findings, respiratory failure, and death. It reports no analysis entries. The statistical plan for prioritizing outcomes or addressing multiplicity is not reported in the registry record. This matters because, in general, evaluating many outcomes can increase the chance of a statistically notable result arising by chance unless the analyses are planned and interpreted with the number and structure of comparisons in mind. No adjustment method, testing hierarchy, or distinction between confirmatory and exploratory analyses is reported.

Missing-data methods are not reported in the registry record. The record does not state how participants without an endpoint assessment, participants who discontinued treatment, or participants with incomplete follow-up were handled. It also does not provide participant flow or outcome-specific denominators. Without those details, it is not possible to assess whether all randomized participants contributed data, whether missingness differed between groups, or how missing observations might affect an estimate.

The efficacy population is described as randomized participants who took at least 1 dose and had RSV confirmed by central laboratory analysis, excluding participants with a baseline co-pathogen missed during screening, with analysis as randomized. The record does not report how many participants met or failed to meet these criteria. The broader safety reporting population and analysis rules are not detailed beyond the posted adverse-event summary. Reasons for termination and the statistical analysis plan are not reported in the registry record. These gaps limit evaluation of the intended analysis, the actual data available, and the robustness of any result; no primary or secondary efficacy analysis is posted for independent interpretation.

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: sepsis (33.3%).

The registry safety summary lists a JNJ-53718678 group with 3 participants at risk for serious adverse events and 1 participant affected. For other adverse events, it lists 3 participants at risk and 2 affected. The summary reports 0 deaths. Sepsis is listed among the top serious adverse event terms at 33.3%. These figures are descriptive entries in the registry; they do not show a comparison with placebo.

At-risk counts describe the participants represented in the relevant summary, while affected counts describe participants reported with the event category. The record does not provide event-level detail, timing, severity for the non-serious events, or an account of whether the same participant appears in more than one category. It also does not report corresponding adverse-event counts for placebo in this summary. The sepsis percentage is presented as a registry figure, but the detailed event listing and calculation context are not reported in the registry record.

These safety observations should be read in light of the reported enrollment of 3 and the absence of a posted comparative analysis. Small descriptive counts do not establish a rate difference, and the registry summary alone cannot determine whether an event was caused by treatment. The record does not provide enough information to compare the safety of JNJ-53718678 with placebo or to characterize uncommon risks.

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

The registry record establishes that the study was designed to compare JNJ-53718678 with placebo in adult and adolescent hematopoietic stem cell transplant recipients with RSV infection of the upper respiratory tract. It specifies a primary endpoint—development of RSV LRTI up to Day 28—and gives an operational definition involving clinical signs or symptoms, virologic testing, imaging, and adjudication. It also reports that the study was randomized, double-blind, and parallel-group, and that it was terminated with enrollment of 3.

Those details describe the research question and the record's status; they do not answer whether treatment groups differed. No primary endpoint outcomes, group denominators, effect estimate, confidence interval, or test result are reported. No efficacy conclusion can be drawn from the design, endpoint definition, or enrollment count. Similarly, the absence of posted efficacy results is not a finding that the treatment had no effect, and it is not evidence that the endpoint did not occur.

The safety summary contains limited counts for the JNJ-53718678 group, including serious and other adverse-event figures and a death count of 0. It does not provide a placebo comparison in that summary. These observations do not establish a comparative safety result or determine whether reported events were related to treatment. The registry's list of secondary outcomes indicates topics of interest, not observed results.

In general, a treatment effect is best understood through a clearly defined comparison, a suitable analysis population, an estimate, and a measure of uncertainty. The posted record lacks those elements for the primary endpoint. It also does not report the reason for termination, detailed participant disposition, or the sponsor's statistical plan. As a result, the record supports a description of trial design and limited safety reporting, but not a conclusion about efficacy, comparative harms, or the clinical importance of any treatment difference.

14. Why This Trial Matters Statistically

This study addresses a defined statistical challenge: evaluating progression from RSV infection of the upper respiratory tract to a clinically adjudicated lower respiratory tract infection in hematopoietic stem cell transplant recipients. The endpoint combines clinical, virologic, and imaging information, and the registry describes an Endpoint Adjudication Committee assessment. Clear endpoint definitions are important because consistent classification is necessary for meaningful comparisons across randomized groups.

The record also illustrates why a trial's design and results must be distinguished. Randomization and double-blinding describe planned protections against bias; they do not, on their own, provide an estimate of the effect. An enrollment of 3, termination status, and the absence of analysis entries sharply limit what can be learned from the posted information. In particular, there are no primary outcome results with which to assess the treatment comparison or its precision.

From a biostatistical perspective, the record highlights the importance of reporting participant flow, group-specific denominators, outcome counts, analysis populations, uncertainty estimates, missing-data decisions, and the handling of multiple outcomes. These elements let readers understand how a trial moved from its planned question to an estimate and how much confidence to place in that estimate. Their absence does not establish a particular treatment result, but it constrains interpretation.

The listed safety figures are also a reminder that descriptive counts and comparative analyses serve different purposes. A registry summary of events can document observations, but without matching comparator information and analytic context it cannot quantify a difference between groups. The statistical importance of this trial therefore lies in the clarity of the research question and the limits of the available results: its design is described, while its primary comparison is not reported.

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 most immediate limitation is the lack of reported primary endpoint results. The registry record gives no event counts, percentages, denominators by group, effect estimate, confidence interval, or statistical test. Enrollment is 3, and the record reports no analysis entries. The information is therefore insufficient to assess the primary comparison or its precision.

The study is listed as terminated, but the reason for termination is not reported in the registry record. Nor does the record explain whether all enrolled participants were randomized, whether all took at least 1 dose, or how many met the stated efficacy analysis criteria. Participant flow and group allocation counts are not reported, so the relationship between total enrollment and the populations included in the efficacy and safety summaries cannot be fully evaluated.

The primary endpoint depends on clinical, virologic, and imaging evidence and includes an Endpoint Adjudication Committee determination. The record provides a definition but does not report adjudication procedures, agreement assessments, or how missing or ambiguous evidence was handled. It also does not report a statistical analysis plan, a prospective sample-size justification, methods for missing data, or a plan for multiplicity across the listed outcome measures.

The intervention descriptions are incomplete, including the full dosing conditions for the adult and adolescent cohorts. The registry's safety summary presents figures for JNJ-53718678 but does not report corresponding placebo counts there. It provides limited event detail and does not clarify participant overlap between categories. These limitations mean the available registry information supports neither a comparative efficacy assessment nor a comprehensive safety comparison.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effects of JNJ-53718678 in Adult and Adolescent Participants Who Had a Hematopoietic Stem Cell Transplantation and Who Are Infected With Respiratory Syncytial Virus (RSV) — NCT04056611.
• Registry record last updated 2025-02-04; status last verified 2025-01.
• Results first posted 2023-04-14.
• 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 2 randomized, double-blind, parallel-group, placebo-controlled study of JNJ-53718678 in adult and adolescent hematopoietic stem cell transplant recipients with RSV infection of the upper respiratory tract. Janssen Sciences Ireland UC is listed as sponsor. The record gives a start date of 2019-12-26, a primary completion date of 2022-02-04, terminated status, and enrollment of 3.

The primary endpoint was the percentage of participants who developed RSV LRTI up to Day 28. The registry record does not report primary endpoint results or analysis entries. Its safety summary lists 3 participants at risk for serious adverse events, 1 affected, 3 at risk for other adverse events, 2 affected, and 0 deaths in the JNJ-53718678 group. Sepsis is listed among the top serious adverse event terms at 33.3%. The reason for termination, detailed participant disposition, and statistical analysis plan are not reported in the registry record.