Effect of Dalcetrapib in Patients With Confirmed Mild to Moderate COVID-19: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Dalcetrapib in Patients With Confirmed Mild to Moderate COVID-19 (NCT04676867), a randomized phase 2 study. The primary outcome is Time to Sustained Clinical Resolution of Symptoms of COVID-19 (Excluding Cough, Sense of Smell and Taste) in Subjects With Confirmed, Mild to Moderate, Symptomatic COVID-19 Treatment With Dalcetrapib.

2. Clinical Question

The clinical question is framed as a time-to-event comparison rather than a comparison of symptom scores at a single visit. The event is sustained clinical resolution, and participants who had not met the definition by 28 days were considered not resolved for this endpoint. The registry reports results for the four groups and an overall log-rank comparison. It does not report a hazard ratio or a separate pairwise effect estimate for each dalcetrapib dose versus placebo.

The study is described as a proof-of-concept trial evaluating efficacy and safety. That description sets the scope of the research question; it does not establish that any dose has a particular clinical effect. The posted medians, confidence intervals, and log-rank p-value describe the observed results and their statistical comparison, while the registry record does not report enough detail to characterize a dose-specific treatment effect beyond those summaries.

3. Trial Design

This was a randomized, quadruple-masked, parallel-group Phase 2a trial with placebo control. The registry record identifies DalCor Pharmaceuticals as the sponsor and gives the status as completed. The study start date was 2021-01-11, and the primary completion date was 2021-05-17. Enrollment was 227.

Participants were assigned to one of four groups: placebo tablets, dalcetrapib 900 mg, dalcetrapib 1800 mg, or dalcetrapib 3600 mg. Each assigned treatment was described as being taken for 10 days. The posted primary outcome results include 53 participants in the placebo group, 55 in the 900 mg group, 48 in the 1800 mg group, and 52 in the 3600 mg group. These are the group sizes associated with the reported primary outcome, rather than an explanation of every analysis population used in the trial.

The registry describes participants as outpatients with confirmed, mild to moderate, symptomatic COVID-19. The parallel-group design compares outcomes among groups assigned to different treatment strategies over the same trial period. Randomization is intended, in general, to reduce systematic differences between assigned groups at baseline. Masking is intended, in general, to limit influences on care, outcome assessment, or reporting that might arise from knowledge of assigned treatment. The registry does not report the specific masking procedures or who was included in the quadruple-masking description.

The registry record does not report the randomization method, allocation ratio, eligibility criteria in sufficient detail for a fuller account, or the statistical rationale for the planned enrollment. It also does not report the treatment adherence details needed to describe how closely participants followed the assigned 10-day course.

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: A total of 227 subjects signed informed consent, 225 of whom were randomized to treatment (2 subjects were not randomized). Of these 225 randomized subjects, 17 subjects did not take any study medication (causes: failed screening criteria, lost to follow-up, or withdrew consent) and were excluded from all analyses. A total of 208 subjects (92.5%) entered the trial and received at least one dose of study medication.

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: Of the 225 randomized subjects, a total of 208 subjects received at least one dose of study medication, for which baseline data are presented here. The overall number of baseline participants in each arm reflects the number of subjects who took at least one dose of study medication in each arm, not the total number randomized in each arm.

6. Primary Endpoint

The registry lists the primary outcome as Time to Sustained Clinical Resolution of Symptoms of COVID-19 (Excluding Cough, Sense of Smell and Taste) in Subjects With Confirmed, Mild to Moderate, Symptomatic COVID-19 Treatment With Dalcetrapib, measured over 28 days.

The primary endpoint is time to sustained clinical resolution of COVID-19 symptoms within 28 days after randomization. The event time is defined as the first day of the last 72-hour period in which the participant met the resolution definition. A participant who had not met the definition 28 days after randomization was considered not resolved.

The registry’s description defines resolution by symptom scores recorded using an electronic patient-reported outcome instrument. The endpoint title specifies that cough, sense of smell, and taste are excluded. The operational description states that no key COVID-19-related symptom may have a score higher than 1 over a 72-hour period, except that smell and taste must have a score of 0 over that period. The registry also describes a symptom scale with scores from 0 to 3 for 12 symptoms and from 0 to 2 for two other symptoms; higher scores indicate worse outcomes.

Time-to-event outcomes are useful when the timing of an event matters, not only whether it occurred by a particular visit. A median summarizes the time by which half of the relevant group has experienced the event under the analysis definition. Participants who do not meet the endpoint definition during follow-up contribute information differently from those who resolve, so the analysis needs methods designed for event-time data. The registry reports medians and 80% confidence intervals, together with a log-rank test across the four groups.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Time-to-event methods analyze how long it takes participants to experience a defined event. For this trial, the event is sustained clinical resolution according to the registry’s symptom-score definition. The observation period ends at 28 days for the primary outcome. Participants who do not meet the resolution definition during that period are treated as not resolved by the end of the stated follow-up window; the registry record does not provide further details about censoring rules or other handling of incomplete event-time information.

What does a median event time describe?

The median event time is a summary of the event-time distribution: it marks the time at which the estimated cumulative proportion experiencing the event reaches the halfway point. It is not the average time to resolution, and it does not describe every participant’s experience. The median can be similar across groups even if other parts of the event-time distributions differ. Conversely, medians alone cannot show whether an apparent difference is statistically precise.

The reported medians are 9 days for placebo, 9 days for 900 mg, 9.5 days for 1800 mg, and 10 days for 3600 mg. Each is accompanied by an 80% confidence interval. Confidence intervals communicate uncertainty in an estimate under the statistical method used. An 80% interval is not interchangeable with an interval at another confidence level, and the registry’s intervals should be interpreted at the stated level. The record does not give the procedure used to construct these intervals.

What does the log-rank test assess?

The log-rank test compares time-to-event information across groups over the observation period. In general, it evaluates whether the event-time patterns differ across groups, taking account of the timing of events rather than reducing the comparison to a single measurement. The registry reports one log-rank p-value, 0.2, for the four groups together. This is an overall test; it does not identify which groups may differ, quantify the size of a particular difference, or give a confidence interval for a treatment effect.

A p-value describes how compatible the observed data are with the null hypothesis used by the test, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry record does not report the trial’s prespecified significance threshold or further details of the primary analysis plan. The p-value should therefore be interpreted as the reported result of the overall test, not as a complete account of the analysis plan.

Why are hazard ratios not interchangeable with medians?

A hazard ratio compares event rates between groups over time under a time-to-event model. It is a relative measure and answers a different question from a median event time, which is expressed in days. The registry does not report a hazard ratio for this primary outcome. A hazard ratio cannot be recovered from the posted medians and confidence intervals alone without additional information about the event-time data and analysis. No such calculation is made in the reported results.

In general, the proportional-hazards assumption used for some hazard-ratio methods means that the relative event rate is treated as reasonably stable over time. If that assumption does not hold, a single hazard ratio may not adequately represent the changing pattern. The registry record does not describe a hazard-ratio analysis or report whether this assumption was assessed, so no conclusion about it can be drawn for this trial.

What do the planning illustrations mean?

Planning sample sizes are design illustrations, not observed power. The described planning approach uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. For time-to-event planning, the stated calculation concerns the total number of events. These assumptions describe an illustrative planning exercise; they are not evidence that the trial was designed using that approach or that a particular power was achieved.

The registry record does not report the trial’s own sample-size justification or the calculations used to select the enrollment target. It also does not report whether interim analyses were planned or conducted. Those matters cannot be inferred from the reported enrollment, endpoint results, or planning assumptions.

How should the secondary outcomes be viewed?

The registry lists 14 outcome measures and 13 posted secondary outcomes, covering viral load, viral clearance, clinical resolution, symptom severity, and a World Health Organization clinical outcome scale. Outcomes that assess different aspects of illness can complement the primary endpoint, but they do not replace it. Each requires attention to its own definition, timing, analysis population, and statistical uncertainty. The registry record does not report a complete analysis plan connecting these outcomes or explaining how multiple comparisons were handled.

10. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a log-rank test across the placebo group and the three dalcetrapib dose groups, with p = 0.2. It also reports group medians and 80% confidence intervals. These are the sponsor’s posted summaries of the primary time-to-event outcome.

The registry does not report a hazard ratio for the primary outcome, nor does it provide the event-time data needed to derive one from the posted summaries. The record also indicates that a two-arm re-calculation for this median-time endpoint was not estimable from the available reported values. Consequently, there is no recalculated pairwise effect estimate to set alongside the sponsor’s overall log-rank result.

The posted medians can be described as group-level summaries, but they do not produce a valid substitute for the sponsor’s overall test or a dose-versus-placebo estimate. The record does not flag a discrepancy between a sponsor estimate and a recalculated estimate. In any case, where a discrepancy is present, the sponsor’s own analysis takes precedence; that situation is not identified in this record. Readers should distinguish the descriptive median summaries from the inferential result of the overall log-rank test.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 14 outcome measures and 13 posted secondary outcomes in addition to the primary endpoint. The secondary outcomes span viral load, viral clearance, clinical resolution, symptom severity, and clinical status. Testing multiple outcomes or making multiple group comparisons can increase the chance of finding an apparently notable result by chance. Statistical approaches to multiplicity may adjust thresholds or otherwise account for the family of questions being tested.

The registry record does not report whether multiplicity adjustments were planned or applied, how outcomes were organized into testing families, or whether the secondary analyses were intended to support confirmatory conclusions. It also does not describe a hierarchy for interpreting the primary and secondary outcomes. Without that information, the secondary results should not be treated as if they were all tested under a single clearly documented error-control strategy.

The record reports the overall log-rank result for the primary endpoint but does not report pairwise tests for each dose versus placebo. The absence of those estimates limits direct interpretation of individual dose comparisons. The reported overall p-value should not be treated as evidence that each individual dose comparison has the same result.

Missing-data methods and analysis populations are also not reported in the registry record. For a time-to-event endpoint, incomplete follow-up and participants who do not meet the endpoint definition within the observation period need to be handled according to prespecified rules. The registry explains that participants not meeting the resolution definition by 28 days were considered not resolved, but it does not give further details about withdrawals, incomplete symptom reporting, censoring, or sensitivity analyses. The posted outcome group sizes do not by themselves establish which analysis population was used or how missing observations were treated.

The registry record does not report whether interim analyses were planned or conducted, or whether the primary analysis plan changed. These omissions leave important aspects of the inferential context unresolved. They do not prove that a particular method was or was not used; they mean that the method is not reported in the registry record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: respiratory distress (5.5%), pneumonia (3.6%), proctitis ulcerative (2.1%), asthenia (2.1%), rash maculopapular (2.1%).

The registry reports serious adverse events among 2 of 53 participants in the placebo group, 4 of 55 in the 900 mg group, 4 of 48 in the 1800 mg group, and 1 of 52 in the 3600 mg group. Deaths are reported as 0 in the placebo group, 0 in the 900 mg group, 1 in the 1800 mg group, and 0 in the 3600 mg group. These counts describe the posted safety results; they do not establish whether an event was caused by assigned treatment.

Other adverse events are reported among 29 of 53 participants receiving placebo, 27 of 55 in the 900 mg group, 33 of 48 in the 1800 mg group, and 46 of 52 in the 3600 mg group. The registry also lists serious-event terms and percentages: respiratory distress, 5.5%; pneumonia, 3.6%; proctitis ulcerative, 2.1%; asthenia, 2.1%; rash maculopapular, 2.1%; and pulmonary embolism, 1.8%. The denominator and the method used to calculate those term-specific percentages are not stated in the registry record.

Safety counts should be read in light of the group sizes and the event definitions used. The registry record does not report causal attribution, event timing, exposure-adjusted rates, or detailed severity and outcome information for each event. The counts therefore describe reported events in the trial, not comparative causal effects or a complete assessment of risk.

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

The primary results describe the observed time to sustained symptom resolution over a 28-day period among participants assigned to placebo or one of three dalcetrapib doses. The reported medians ranged from 9 days to 10 days, and the overall log-rank test had p = 0.2. These findings are a statistical summary of this trial’s endpoint and analysis, not a complete account of all clinical outcomes or evidence about other populations.

The result does not establish a dose-specific effect versus placebo. The registry reports an overall comparison across four groups, but no hazard ratios or pairwise confidence intervals for the primary outcome. The medians are useful descriptive summaries, while the 80% confidence intervals indicate uncertainty at the stated confidence level. They should not be mistaken for more precise or more comprehensive evidence than the record contains.

The result also does not establish that the groups are equivalent. A failure to obtain a small p-value is not, by itself, proof that treatment effects are absent or that outcomes are the same. Demonstrating equivalence or non-inferiority requires a design and analysis with specified margins and appropriate estimates; those details are not reported in the registry record.

The primary endpoint is based on a symptom-score rule and requires resolution to be sustained over a 72-hour period. It does not represent every possible measure of recovery. The registry lists secondary outcomes for viral measures, symptoms, clinical resolution, and clinical status, but their presence does not tell readers how those outcomes compare or how they were analyzed. The registry record does not report enough detail to assess multiplicity, missing data, or the full analysis population.

These findings should be understood within the limits of a completed Phase 2a proof-of-concept trial with 227 participants and a 28-day primary endpoint window. The record supports description of the reported group medians, confidence intervals, overall test, and adverse-event counts. It does not support a broader conclusion about clinical effectiveness, causal safety differences, or outcomes beyond those reported.

14. Why This Trial Matters Statistically

This trial illustrates why a time-to-event endpoint requires more than a comparison of group medians. Time to sustained symptom resolution depends on when participants meet a defined event criterion, and the log-rank test uses event-time information across the observation period. A median is an accessible summary, but it does not capture every feature of the event-time distributions or quantify a dose-specific comparison.

The registry also illustrates the importance of reading the inferential result at the level at which it was reported. The posted p-value is an overall comparison among placebo and three dose groups. Without pairwise estimates and confidence intervals, it cannot be translated into a separate treatment-effect estimate for each dose versus placebo. The 80% confidence intervals around the medians express uncertainty, but they are not a substitute for the missing comparative effect estimates.

The endpoint definition matters to the statistical interpretation. Resolution is not simply a single low symptom score at a visit; it must satisfy the stated criterion over a 72-hour period, within 28 days after randomization. That makes the timing and persistence of symptom scores relevant to event classification. The registry record does not give detailed information about incomplete reporting or censoring, which can be important for time-to-event analyses.

Finally, a registry record can leave meaningful uncertainty about analysis choices. This record does not report a complete statistical analysis plan, missing-data methods, multiplicity handling, or the trial’s own sample-size justification. The posted results remain informative as descriptions of what was reported, while the absent details limit how fully the statistical evidence can be appraised. Distinguishing those two points is central to careful interpretation.

15. Limitations

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

The primary comparison is reported as an overall log-rank test, not as a set of dose-versus-placebo estimates. The registry record gives no hazard ratio or pairwise confidence interval for the primary endpoint. This limits the ability to quantify the size and precision of any individual dose comparison from the posted results.

The primary outcome uses an 80% confidence interval for each median. That is the uncertainty level reported in the registry, and it should not be silently treated as a 95% interval. The record does not describe the method used to calculate these intervals. It also does not provide the event-time data needed for an independent analysis of the endpoint.

The registry record does not report the statistical analysis plan, analysis populations, missing-data procedures, censoring rules, interim analyses, or multiplicity strategy. It does not report the trial’s own sample-size justification. These omissions make it difficult to assess how planned analyses relate to posted results, how incomplete observations were handled, or how secondary findings should be interpreted alongside the primary outcome.

Although the trial is described as randomized and quadruple-masked, the record does not provide the randomization procedure or the specific masking arrangements. It reports group sizes for the primary outcome and safety counts, but does not explain all denominators or analysis sets. The denominator for the listed serious-event term percentages is not stated.

The primary endpoint is limited to a symptom-based definition and follow-up within 28 days. The registry’s endpoint title and operational description contain different wording around excluded symptoms and the special smell-and-taste score rule; the posted definition should therefore be read as written rather than expanded by assumption. The record provides no basis for extending the primary result beyond this endpoint, trial population, and observation period.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effect of Dalcetrapib in Patients With Confirmed Mild to Moderate COVID-19 — NCT04676867.
• Registry record last updated 2022-12-07; status last verified 2021-06.
• Results first posted 2022-12-07.
• 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

NCT04676867 is a completed randomized, quadruple-masked, parallel-group Phase 2a trial sponsored by DalCor Pharmaceuticals. It enrolled 227 outpatients with confirmed, mild to moderate, symptomatic COVID-19 and compared placebo with dalcetrapib at 900 mg, 1800 mg, and 3600 mg, each taken for 10 days.

The primary endpoint was time to sustained clinical resolution within 28 days after randomization. Reported median times were 9 days for placebo, 9 days for 900 mg, 9.5 days for 1800 mg, and 10 days for 3600 mg, each with an 80% confidence interval. The overall log-rank p-value was 0.2. The registry record does not report hazard ratios or pairwise confidence intervals for the primary outcome.

It also lists 13 secondary outcomes and reports serious adverse events, other adverse events, and deaths by group. Details of the statistical analysis plan, missing-data methods, multiplicity handling, and sample-size justification are not reported in the registry record.