A Study of JNJ-64281802 in Participants With Confirmed Dengue Fever: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of JNJ-64281802 in Participants With Confirmed Dengue Fever (NCT04906980), a randomized phase 2 study. The primary outcome is Area Under the Log10-Transformed Dengue Virus (DENV) RiboNucleic Acid (RNA) Viral Load (VL) Curve From Baseline Until Day 5 (AUCD1-D5 [log10VL])..

2. Clinical Question

In general, a randomized placebo-controlled design is intended to compare outcomes between groups while reducing the influence of systematic differences in treatment assignment. Double masking is intended to limit the influence of treatment knowledge on participants’ experiences and on study conduct or assessment. Those design features describe the planned comparison, but they do not supply evidence about the magnitude or precision of an effect. With no reported primary outcome measurements or analysis, the registry record does not establish what the viral-load comparison would have shown. The reason for termination and further details about participant characteristics are not reported in the registry record.

3. Trial Design

The registry identifies this as a Phase 2a, randomized, double-blind, placebo-controlled trial with a parallel design. It lists JNJ-64281802 and placebo as the two interventions. Enrollment was 5 participants. The study started on 2022-01-24, had a primary completion date of 2022-09-24, and is listed as terminated. The reason for termination is not reported in the registry record.

The planned treatment schedule differed between the arms. The JNJ-64281802 description specifies 2 initial loading doses up to Day 2, followed by maintenance doses on Days 3, 4, and 5. The placebo description specifies oral doses every 8 hours and once daily on Day 4 and Day 5. These descriptions state the planned schedules; they do not establish how much treatment participants actually received or whether each participant followed the schedule.

In general, a parallel design assigns participants to a group and compares outcomes across groups, rather than having each participant receive both interventions in sequence. Randomization is intended to make assignment independent of participant characteristics, though it cannot guarantee that small groups will be similar. Double masking means that treatment assignment is concealed from specified parties, but which roles were masked and how masking was implemented are not reported in the registry record.

The record does not report the randomization procedure, allocation concealment details, eligibility criteria, planned sample-size justification, or the reason for choosing the treatment schedule. It also does not report a statistical analysis plan or a description of analysis populations. These omissions limit what can be concluded about the intended conduct beyond the design features and schedules explicitly recorded. The small enrollment and absence of primary outcome data mean that the stated design cannot be treated as a completed comparative assessment of antiviral activity.

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: Due to small number of enrolled participants, planned data collection and analysis was not performed for the efficacy objectives and no data was reported for efficacy outcome measures and thus only safety analysis data were reported.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Due to the small number of enrolled participants, planned data collection and analysis was not performed and thus no data was reported for this outcome measure.

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 Area Under the Log10-Transformed Dengue Virus (DENV) RiboNucleic Acid (RNA) Viral Load (VL) Curve From Baseline Until Day 5 (AUCD1-D5 [log10VL])., measured over Baseline (Day 1) upto Day 5.

The planned primary endpoint was the area under the curve of log10-transformed dengue virus RNA viral load from baseline on Day 1 through Day 5. It was intended to measure the cumulative pattern of viral RNA over that period, rather than relying on a single measurement at one time point. The registry describes this endpoint as a way to assess the antiviral activity of JNJ-64281802 versus placebo in participants with a primary dengue virus infection.

In general, an area-under-the-curve measure combines repeated measurements over time into a summary of both their levels and their duration. Applying a logarithmic transformation changes the scale on which viral-load measurements are represented; the record specifically names a log10 transformation. A lower curve area could represent a lower overall burden on the measured log scale, but no such value or comparison is reported for this study.

The endpoint’s unit, statistical parameter, and dispersion are not reported in the registry record. Nor are the timing of individual measurements, handling of measurements below detection limits, or details of the planned calculation. Most importantly, the registry states that planned data collection and analysis were not performed because of the small number enrolled. There is therefore no reported endpoint estimate, uncertainty interval, or treatment comparison to interpret.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, double-blind, placebo-controlled parallel trial. It does not report the statistical analysis plan, the analysis populations, or the methods intended for the primary outcome. The explanation below distinguishes the general statistical ideas relevant to this design from methods that can be attributed to this particular study.

What does randomization contribute?

In general, randomization assigns participants to study groups using a chance-based process. Its purpose is to reduce systematic differences in participant characteristics between groups, so that an outcome comparison can be more plausibly related to the assigned interventions. Randomization does not guarantee balance in every trial, and chance imbalances can occur, especially when the number enrolled is small. The registry identifies the study as randomized but does not report the sequence-generation method, allocation concealment, or any checks of group balance.

What does double masking mean?

In general, masking is intended to reduce the influence of knowing treatment assignment on participants, care, outcome assessment, or reporting. A matching placebo can help maintain masking when the study compares an active intervention with an inactive comparator. The record calls the study double-blind and describes matching placebo, but it does not specify which people were masked, how the masking was maintained, or whether it was assessed. It is therefore possible to describe the design label, but not to evaluate the success of masking from the registry record.

Why summarize viral load over time?

The planned outcome integrates log10-transformed dengue virus RNA viral-load measurements from baseline on Day 1 through Day 5. In general, a repeated-measures summary can reflect how an outcome changes across a time window and can be more informative about the overall trajectory than an isolated measurement. An area under the curve combines the magnitude of measurements with the time over which those measurements occur. A log transformation changes the measurement scale and can help represent data with a wide range of values. These are general properties; the registry does not report the detailed measurement schedule or the exact calculation procedure planned for this endpoint.

Because the outcome was not collected and analyzed as planned, no observed curve area, treatment contrast, standard error, confidence interval, or p-value is available. A statistical method cannot create an outcome estimate without the underlying observations or an explicitly reported result. The record does not report any alternative primary analysis, adjustment for baseline viral load, model for repeated measurements, or handling of values that might be missing or below a measurement threshold.

How should uncertainty be understood?

In general, a point estimate is the sample-based summary of an effect, and its uncertainty depends on both the variability in the data and the amount of information available. A confidence interval conveys uncertainty around an estimate under the assumptions of the chosen method. It does not show the probability that a particular hypothesis is true. A p-value addresses compatibility with a specified null model and is not, by itself, a measure of the size or importance of an effect. Since the primary outcome has no reported data or analysis, none of these measures is available for the planned viral-load comparison.

Small samples generally provide limited information for estimating between-group differences and can yield imprecise estimates. That general point does not permit calculation of a study-specific uncertainty interval or power from the enrollment count alone. The registry does not report a trial-specific sample-size justification, and the primary outcome was not analyzed. Any hypothetical planning calculation would be distinct from observed power or from an observed treatment effect. No numerical planning result for this trial is reported in the registry record.

What can the safety counts tell readers?

The safety record reports the number of participants at risk and the number with serious or other adverse events in each group. These are descriptive counts. In general, adverse-event counts can summarize how many participants experienced at least one event, but they do not communicate event severity beyond the stated classification, timing, duration, or causal relationship unless those details are reported. The registry lists no serious adverse events and no deaths in either group, and lists other adverse events for all participants represented in each group. With only the recorded counts, the safety information should not be treated as a detailed comparative analysis.

The record lists 12 outcome measures and 0 analysis entries, but it does not identify statistical tests for secondary outcomes or describe any adjustment for multiple comparisons. It also does not report a prespecified hierarchy of outcomes, missing-data procedures, or criteria for excluding participants from an analysis. These details matter because different analytical choices can affect estimates and their interpretation. Their absence from the registry record should not be filled in by assuming a conventional approach.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures, including the planned viral-load area under the curve, safety outcomes, plasma concentrations of JNJ-64281802, whether dengue virus RNA was detectable, and time to undetectable dengue virus RNA. It reports 0 analysis entries. No multiplicity strategy, testing hierarchy, or distinction between confirmatory and exploratory secondary analyses is reported in the registry record.

In general, when several outcomes or comparisons are tested, the chance of observing at least one apparently unusual result can increase if each test is treated as an independent primary test. Prespecified hierarchy or multiplicity adjustment can help define how such results should be interpreted. Those are general considerations, not a description of methods used in this trial. Since the primary outcome was not analyzed and the registry does not list analysis methods, there is no basis for determining how multiplicity would have been handled.

The record says planned collection and analysis for the primary outcome were not performed because of the small number enrolled. This is not the same as a reported missing-data analysis: there are no outcome data or missingness procedures described for that endpoint. The registry does not report whether any participants had partial measurements, how incomplete observations would have been treated, or what analysis population was planned.

In general, an analysis population defines which participants contribute to a particular result, such as all randomized participants or those meeting specified treatment and assessment criteria. The registry record does not name a population for the primary or secondary analyses. It also does not report imputation, sensitivity analyses, or a method for addressing deviations from the planned treatment schedule. These omissions prevent assessment of how incomplete data or participant exclusions might have affected an estimate.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists 2 participants at risk in the JNJ-64281802 group and 3 in the placebo group. It records no serious adverse events in either group and no deaths in either group. Other adverse events are listed for 2 participants in the JNJ-64281802 group and 3 participants in the placebo group.

These figures are participant counts. In general, a count of participants with an event is different from a count of all event episodes, since one participant may experience more than one event. The registry information recorded for this trial does not give event-level detail for the other adverse events. It does not identify their terms, timing, duration, severity, or assessed relationship to study treatment. The serious-event listing contains no serious-event terms.

The groups are small, and the counts are descriptive rather than a reported statistical comparison. No percentage or relative-risk calculation is needed to read the reported counts, and the registry does not report an inferential safety analysis. The absence of recorded serious events or deaths in these groups should not be interpreted as establishing the absence of risk. The safety figures should also be kept distinct from the primary viral-load question, for which no outcome data were reported.

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

The registry record documents a planned randomized comparison of JNJ-64281802 with placebo in participants with confirmed dengue fever and a primary dengue virus infection. Its primary endpoint was intended to summarize log10-transformed viral RNA from baseline on Day 1 through Day 5. The study enrolled 5 participants and is listed as terminated.

The central result is that the planned primary data collection and analysis were not performed because of the small number enrolled. No primary viral-load outcome data are reported. That means the record does not provide an effect estimate, direction of effect, confidence interval, or p-value for the primary comparison. It cannot establish whether the observed viral-load pattern differed between groups, or how precisely any difference could have been estimated.

The available safety counts show no serious adverse events and no deaths in either group, with other adverse events listed for 2 participants in the JNJ-64281802 group and 3 in the placebo group. These counts describe what the safety record reports; they do not answer the antiviral-activity question. The registry does not supply further event detail in the record summarized for this trial.

In general, a trial’s design describes how an answer was intended to be obtained, while its results require observed measurements and analyses. Randomization, masking, and a clearly defined endpoint can support a useful comparison when data are collected and analyzed, but they are not themselves evidence of an intervention effect. Here, the planned primary comparison remains unanswered in the registry record. The reason for termination, the statistical plan, analysis populations, and detailed handling of missing data are not reported. No conclusion about efficacy or treatment benefit should be inferred from the design description or the limited safety counts.

13. Why This Trial Matters Statistically

This study illustrates an important distinction in clinical-trial interpretation: a well-defined planned endpoint is not the same as a reported result. The registry specifies a viral-load measure intended to represent the course of dengue virus RNA from baseline through Day 5. Yet the record states that planned collection and analysis were not performed because of the small number enrolled. Without the endpoint observations and analysis, the trial cannot offer a reported estimate of the planned comparison.

Enrollment of 5 participants also shows why the amount of information matters. In general, small studies can be useful for feasibility or early investigation, but estimates from small samples are often uncertain and may be sensitive to individual observations. This is a general statistical concern, not a study-specific estimate of uncertainty: the registry reports no primary outcome estimate or interval with which to quantify precision.

The record also demonstrates why safety counts and efficacy outcomes answer different questions. It lists adverse-event and serious-event counts, but those counts do not replace the absent viral-load analysis. Likewise, a randomized and masked design describes safeguards in the intended comparison, but cannot compensate for a lack of analyzed outcome data.

For readers assessing the evidence, the key distinction is between the study’s planned question and what the registry reports as observed and analyzed. The planned question was whether JNJ-64281802 differed from placebo in the viral-load endpoint. The available record does not answer that question. Recognizing this boundary prevents design details or sparse safety counts from being mistaken for evidence about antiviral activity.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most direct limitation is that the planned primary outcome data were not reported. The registry explicitly states that planned collection and analysis were not performed because of the small number enrolled. As a result, there is no primary estimate or uncertainty measure to interpret. Enrollment was 5 participants, and the record is marked terminated; the reason for termination is not reported in the registry record.

The record does not report a statistical analysis plan, sample-size justification, randomization procedure, allocation concealment, analysis populations, or missing-data methods. It also does not give detailed measurement timing or procedures for calculating the viral-load area under the curve. These omissions make it impossible to evaluate the intended analytical choices or determine whether any alternative analysis was conducted.

Safety information is limited to participant counts. The record lists no serious adverse events or deaths in either group and lists other adverse events for 2 participants in the JNJ-64281802 group and 3 in the placebo group. It does not report detailed terms or event-level descriptions for those other adverse events. The registry lists 12 outcome measures but 0 analysis entries, so the available safety counts should not be confused with a full analysis of the listed outcomes.

These limitations restrict interpretation to the recorded design, enrollment, and safety counts. They do not establish why the study ended or what unreported measurements might have shown. The reason for termination and further details about outcome collection are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of JNJ-64281802 in Participants With Confirmed Dengue Fever — NCT04906980.
• Registry record last updated 2024-03-01; status last verified 2024-01.
• Results first posted 2024-03-01.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry describes a Phase 2a randomized, double-blind, placebo-controlled parallel study of JNJ-64281802 in participants with confirmed dengue fever. The listed enrollment is 5, and the study status is terminated. The primary endpoint was the area under the curve of log10-transformed dengue virus RNA viral load from baseline on Day 1 through Day 5.

The registry states that planned collection and analysis of the primary outcome were not performed because of the small number enrolled, and no primary outcome data were reported. The safety record lists no serious adverse events or deaths in either group; other adverse events are listed for 2 participants in the JNJ-64281802 group and 3 in the placebo group. The reason for termination and the detailed statistical plan are not reported in the registry record.