Safety and Efficacy of Rayaldee for Treating Mild to Moderate COVID-19: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy of Rayaldee for Treating Mild to Moderate COVID-19 (NCT04551911), a randomized phase 2 study. The primary outcome is Concentration of Serum Total 25-hydroxyvitamin D Attained at or Above 50 ng/mL at Visit 3 (Day 14)..

2. Clinical Question

The clinical framing and the primary endpoint are not identical: the trial enrolled people with COVID-19, but its primary posted measure is attainment of a serum vitamin D concentration threshold. Results on that endpoint therefore address the biochemical measure described in the record. They do not, by themselves, answer whether symptoms resolve sooner or whether participants avoid urgent care or hospitalization.

3. Trial Design

REsCue is described as a phase 2 randomized, parallel-group, double-blind, placebo-controlled study of Rayaldee for symptomatic adults with mild to moderate COVID-19 who tested positive for SARS-CoV-2. The registry also labels the study quadruple masked; the identities of the groups whose knowledge was masked are not reported in the registry record. The study is listed as completed, with 171 enrolled participants.

The registry record gives a start date of 2020-11-02 and a primary completion date of 2021-10-08. It describes the study as single or multi-center, but the actual number of centers is not reported in the registry record. The record lists Rayaldee and placebo as the two drug interventions. Its dosing description specifies a loading period on Days 1, 2 and 3 and a maintenance period on Days 4-27, but the maintenance instructions are truncated; the complete regimen is not reported in the registry record.

The primary outcome is the number and percentage of participants attaining serum total 25-hydroxyvitamin D at or above 50 ng/mL at Visit 3, Day 14. The primary outcome population is identified as per protocol. The arm counts for that result are 51 of 65 with Rayaldee and 10 of 69 with placebo. The total enrollment and the analyzed arm counts are not the same quantities; the registry record does not explain the relationship between enrollment and these per protocol counts.

Secondary outcomes include symptom-resolution measures, emergency room or urgent care visits, oxygen saturation below 94% without supplemental oxygen, hospitalization, mechanical ventilation, and deaths. Numerical results are available for some, but not all, of the secondary outcomes. The original sample-size justification, detailed analysis plan, and reasons for the selection of analysis populations are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Per protocol population

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: Analysis is for the per protocol population, subjects who had a baseline aggregate five symptom score of \>5 and did not have a major protocol deviation prior to resolution.

6. Primary Endpoint

The registry lists the primary outcome as Concentration of Serum Total 25-hydroxyvitamin D Attained at or Above 50 ng/mL at Visit 3 (Day 14)., measured over 14 days.

The primary endpoint counts participants whose serum total 25-hydroxyvitamin D concentration reached or exceeded 50 ng/mL at Visit 3, on Day 14. It is a binary outcome for each participant: the concentration either met the stated threshold or it did not. The registry describes the result as a number and percentage of participants and identifies the analysis population as per protocol.

A threshold endpoint can make a laboratory result easier to interpret as a target-attainment measure than a set of raw concentrations. In general, counting participants on either side of a prespecified threshold focuses the comparison on how often the defined target was attained. That approach also discards information about the actual concentration values and about how far participants were from the threshold. The threshold is part of the endpoint definition; the reason for choosing 50 ng/mL and the protocol's rationale for using this measure are not reported in the registry record.

The primary outcome is biochemical rather than a direct measure of symptom burden, clinical recovery, or health-care use. The study title and population concern COVID-19, but the primary result should be read as evidence about the reported vitamin D threshold in the analyzed population. It does not establish what happened on other clinical outcomes. The record includes symptom and health-care-use measures as secondary outcomes, which answer different questions and have their own uncertainty.

7. Results Posted in the Registry

• Rayaldee: 78.5% (51/65) versus 14.5% (10/69) on control; risk difference 64.0 percentage points (95% CI 51.0 to 77.0), risk ratio 5.41 (3.01–9.74); unadjusted two-proportion z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Time to Resolution of COVID-19 Five Aggregated Symptoms

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Rayaldee: mean 12.00 versus 12.60 on control; difference -0.60 (95% CI -3.61 to 2.41), standardized effect d = -0.07; z-test p = 0.696.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rayaldee and the control. The interval gives the range of effects that remain compatible with the data.

Number of Subjects Who Had an COVID-19 Five Aggregated Symptoms Score >5 at Baseline Who Experienced Symptom Resolution as of Day 10

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Rayaldee: 58.5% (38/65) versus 59.4% (41/69) on control; risk difference -1.0 percentage points (95% CI -17.6 to 15.7), risk ratio 0.98 (0.74–1.31); unadjusted two-proportion z-test p = 0.910.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rayaldee and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Emergency Room/Urgent Care Visits

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Rayaldee: 0.0% (0/65) versus 4.3% (3/69) on control; risk difference -4.3 percentage points (95% CI -9.2 to 0.5); unadjusted two-proportion z-test p = 0.089.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rayaldee and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes address several different aspects of COVID-19: symptom duration or resolution, urgent-care use, oxygen saturation, hospitalization, mechanical ventilation, and deaths. They complement the primary laboratory endpoint by asking about symptoms and clinical events rather than threshold attainment. The available numerical results cover a mean time-to-resolution measure, a Day 10 symptom-resolution count, and urgent-care visits. Numerical results for other listed secondary outcomes are not reported in the registry record.

The overall pattern across the reported secondary results is not a consistent signal of separation across every outcome. The primary endpoint concerns whether a vitamin D concentration crossed a threshold, whereas the symptom and care-use measures concern participant experience or events. The primary finding therefore cannot be used as a substitute for results on symptom recovery, hospitalization, or other clinical outcomes. Different endpoints can vary independently, and the registry results should be interpreted outcome by outcome.

Secondary results generally carry less evidential weight than a clearly prespecified primary analysis, especially when many outcomes are examined. Multiple unadjusted tests can produce apparently notable results by chance, and the registry record does not report a multiplicity procedure or testing hierarchy. Secondary analyses can still be informative, but they are best viewed as supporting or exploratory unless their role and analysis were specified in advance. Those details are not reported in the registry record.

Interpretation is also constrained by the limited reporting of analysis methods and populations. The record does not provide full numerical results for all listed secondary endpoints, or explain missing observations and analysis denominators for each one. The secondary outcomes thus broaden the questions considered, but do not provide a complete basis for claims about every clinical event listed in the study record.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Time to Resolution of COVID-19 Five Aggregated Symptoms
• Number of Subjects Who Had an COVID-19 Five Aggregated Symptoms Score >5 at Baseline Who Experienced Symptom Resolution as of Day 10
• Proportion of Subjects Who Had an COVID-19 Five Aggregated Symptoms Score >5 at Baseline Who Experienced Symptom Resolution as of Day 10
• Number of Participants With Emergency Room/Urgent Care Visits
• Number of Participants With Oxygen Saturation Below 94% (Without Supplemental Oxygen)
• Number of Participants With Hospitalizations
• Number of Participants With the Requirement for Mechanical Ventilation
• Number of Participant Deaths

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary: each participant either attained the threshold of serum total 25-hydroxyvitamin D at or above 50 ng/mL by Day 14 or did not. For a binary endpoint, an arm's event proportion is the number meeting the endpoint divided by the number analyzed in that arm. The registry provides the primary counts and an unadjusted risk difference comparing the arms. A risk difference expresses the absolute contrast in event proportions, rather than a relative comparison. The reported estimate is 0.640.

What does the confidence interval describe?

A confidence interval gives a range of values compatible with the observed data under the statistical method used. It conveys uncertainty around an estimate; it is not a range containing the outcomes of individual participants. For the primary risk difference, the 95% confidence interval is 0.510 to 0.770. The registry record does not report the confidence-interval construction method, so a more specific description of that calculation is not available.

How should the p-value be read?

A p-value summarizes how unusual data at least as discrepant as those observed would be under a specified null model. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. The primary comparison is reported as p < 0.001. The comparison is unadjusted in the posted results. The registry record does not report the sponsor's full analysis specification, including any covariate adjustment or testing hierarchy.

Why are the secondary outcomes analyzed differently?

The reported time to resolution measure is presented as a mean in days with a standard deviation for each arm. Its comparison is a mean difference, -0.6 days, with a 95% confidence interval from -3.612 to 2.412. A mean difference compares average values on the outcome's original scale. The standard deviation describes participant-to-participant variability within an arm; it is not the uncertainty of the estimated mean difference. The registry record does not report a detailed model or adjustment for this secondary analysis.

The Day 10 symptom-resolution count and urgent-care visit outcome are binary. Their comparisons use risk differences and confidence intervals. For the Day 10 measure, the comparison is based on participants whose baseline five-symptom score was greater than 5. The urgent-care measure reports the number of participants with visits. Binary outcomes with few events can yield unstable estimates and broad uncertainty, particularly when an arm has no observed events. General statistical practice treats such estimates cautiously; the registry record does not report a specialized sparse-data method for this outcome.

What does an unadjusted comparison leave out?

An unadjusted comparison contrasts the posted arm-level results without accounting for other measured participant characteristics. It is straightforward to interpret, but it may not match a trial's prespecified primary analysis if that analysis includes covariates, stratification, or other adjustments. The registry record does not report whether the primary comparison is the sponsor's prespecified inferential analysis or whether other models were used. No discrepancy is identified in the posted comparison, but the absence of a reported detailed analysis plan limits assessment of its full specification.

There are multiple outcomes: the primary endpoint and a set of secondary measures. Testing many outcomes can increase the chance that at least one result appears statistically notable by chance. A multiplicity adjustment or a prespecified hierarchy can address that issue, but the registry record does not report whether either was used. Accordingly, secondary p-values should be understood as unadjusted results, not as a family-wise confirmatory analysis. The number of analyses reported in the registry does not supply the missing testing plan.

Why does the analysis population matter?

The primary endpoint is explicitly reported for the per protocol population. That population designation indicates that the primary result is not presented simply as a count of everyone enrolled. The rules used to define the per protocol population, exclusions from it, and handling of missing endpoint measurements are not reported in the registry record. The primary arm denominators are 65 and 69, while enrollment is 171; the record does not explain the difference. The safety figures use 80 participants at risk in each arm and should not be assumed to share the primary efficacy population or denominator.

General principles of randomized-trial analysis favor clearly defined populations and prespecified handling of missing data, because exclusions or missing measurements can affect comparability and interpretation. Here, the registry record does not report the missing-data methods, sensitivity analyses, or the detailed analysis population rules. These gaps do not change the posted arithmetic, but they limit how fully readers can assess the robustness of the estimates.

11. Confidence Intervals and Precision

The primary risk difference is 0.640, with a 95% confidence interval from 0.510 to 0.770. The interval lies on the positive side of zero and is consistent with a sizeable contrast in threshold attainment for the analyzed population. Its width also reflects uncertainty: the true contrast compatible with the data could be meaningfully smaller or larger than the point estimate. The interval does not account for unreported choices about the analysis population, missing data, or multiplicity.

Precision differs across outcomes. For mean time to symptom resolution, the 95% confidence interval for the mean difference is -3.612 to 2.412 days. It includes zero and permits values in either direction. For Day 10 symptom resolution, the risk-difference interval is -0.176 to 0.157. For urgent-care visits, it is -0.092 to 0.005. These intervals likewise include zero; they do not establish that the arms are identical, but they show that the estimates are compatible with no difference as well as with some differences in either direction.

Confidence intervals are especially important when event counts are small. The urgent-care outcome has only 3 reported events in one arm and none in the other, so its point estimate alone would give an incomplete impression of uncertainty. More generally, a nonsignificant p-value is not proof of no effect, and a statistically notable p-value does not by itself show that an estimate is precise or important. The registry record does not report confidence intervals for every listed endpoint, and numerical results for the remaining secondary outcomes are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effect, not the trial's original design justification. For the reported binary and mean outcomes, the figures are participants per arm. The assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario uses the stated fraction of the observed effect as the effect to detect. The registry record does not report the original sample-size assumptions or justification for the trial.

The 80% power column gives the illustrative number of participants per arm that the stated assumptions would require for an 80% chance of detecting the selected effect if that effect were the true one. The 90% power column applies the same idea with a higher target chance of detection. These are planning concepts: power is a property of a proposed design under assumed conditions, not a probability that the trial's result is correct. The figures are not observed power.

Rows using a smaller fraction of the observed effect represent a more modest target difference. Detecting a smaller difference generally requires more participants, because it is harder to distinguish a subtle signal from ordinary sampling variation. The illustrations therefore help show how strongly sample-size requirements depend on the effect assumed for planning; they do not establish what enrollment the original investigators should have chosen.

These calculations use the observed effect as their starting point, which can be an uncertain basis for future planning, particularly when an estimate comes from a limited sample. They also rely on the stated simplified assumptions and do not incorporate any unreported design features. They should be read as comparative planning scenarios rather than as a reconstruction of the trial's protocol or as evidence about the trial's achieved power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.145; treatment proportion p₁ = 0.785; average p̄ = 0.465.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.7053 = 1.3825.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5412 = 0.4555.
4. n = (1.3825 + 0.4555)² / (0.6397)² = 8.3, rounded up to 9 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.144927536231884                          # control proportion
p1 <- 0.784615384615385                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(4551911)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 9 (80% power), 11 (90% power)
 75% of observed effect: n per arm = 15 (80% power), 20 (90% power)
 50% of observed effect: n per arm = 32 (80% power), 42 (90% power)
power.prop.test: 8.3 
Simulated power at n = 9 per arm: 0.828 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and multiple secondary outcomes. When many outcomes are tested, the chance of at least one small p-value under a situation where none of the underlying effects exists can increase. Trial protocols commonly address this through a prespecified hierarchy, adjustment, or by treating secondary analyses as exploratory. Whether this trial used a multiplicity procedure, and how any testing hierarchy was defined, are not reported in the registry record. The posted secondary comparisons should therefore be read as unadjusted rather than as evidence from a documented family-wise testing plan.

The record identifies the primary analysis population as per protocol, but does not report the criteria used to define that population or the number and reasons for exclusions. Enrollment is 171, while the primary endpoint arm denominators are 65 and 69. The registry does not explain the relationship between those figures. It also does not report the number of participants with missing primary endpoint measurements or how missing observations were handled.

Missing-data handling can matter because complete-case estimates may be affected if the availability of an outcome is related to participant characteristics or outcomes. General statistical practice may include sensitivity analyses to examine how conclusions change under different assumptions about missing observations. Such methods and sensitivity analyses are not reported in the registry record. No inference about the amount or consequences of missing data can be made from the posted counts alone.

The safety record lists 80 participants at risk in each arm, different from the primary endpoint denominators. The registry record does not explain the population or denominator differences, so these safety figures should be kept distinct from the efficacy analysis. The detailed statistical analysis plan, including any interim analyses, is not reported in the registry record.

15. 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: covid-19 pneumonia (3.8%), acute respiratory failure (2.5%), covid-19 (1.2%).

The safety summary reports serious adverse events among 80 participants at risk in each arm. Three Rayaldee participants and one placebo participant are recorded as affected by a serious adverse event. For other adverse events, the record lists 12 affected participants in each arm. No deaths are recorded in either arm. These are counts in the registry's stated safety groups; the record does not explain how those groups relate to the per protocol population used for the primary endpoint.

The registry also lists COVID-19 pneumonia at 3.8%, acute respiratory failure at 2.5%, and COVID-19 at 1.2% among the top serious adverse event terms. The record does not specify in the posted terms whether these categories overlap or provide further event-level detail, so they should not be added or treated as mutually exclusive categories. The term percentages should be read as reported, without assuming a denominator beyond what the record states.

These figures are descriptive. The registry record does not provide a detailed safety analysis, comparative uncertainty estimates, or information that would establish whether reported events were caused by study treatment. A small number of events can leave substantial uncertainty about differences between groups.

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

The primary result shows that, among participants in the reported per protocol population, more Rayaldee-arm participants met the Day 14 serum vitamin D threshold than placebo-arm participants. The risk difference and its confidence interval quantify the magnitude and precision of that biochemical contrast. This is the result the registry identifies as primary.

It does not, on its own, show that participants had faster symptom resolution, fewer hospitalizations, or fewer other COVID-19 complications. Those are different outcomes. The secondary symptom and urgent-care comparisons reported in the registry do not provide clear evidence of a between-arm difference, and results for several other listed secondary outcomes are not reported in the registry record. The primary endpoint should not be recast as a clinical recovery endpoint.

A threshold result also does not reveal the distribution of individual serum concentrations or how far participants were above or below the threshold. It answers the narrower question of how many attained the defined target. The registry record does not report why that threshold was selected, the original statistical analysis plan, multiplicity handling, or missing-data methods. These limitations matter when considering how broadly to interpret the result.

The findings apply to the participants and analysis population represented in the posted results. They should not automatically be extended to populations or circumstances not described in the record. The trial is described as phase 2; the registry result alone does not settle questions beyond its measured endpoints and reported analyses. No treatment recommendation follows from these registry statistics.

17. Why This Trial Matters Statistically

This trial illustrates why the endpoint definition matters as much as the study title. Although the study addresses symptomatic COVID-19, its primary outcome is attainment of a serum vitamin D threshold. A strong contrast on that biochemical endpoint is not interchangeable with evidence about symptom duration or serious clinical events. Keeping those questions separate prevents an endpoint result from being interpreted more broadly than it supports.

It also illustrates how effect estimates, confidence intervals, and p-values contribute different information. The primary comparison is large on its reported risk-difference scale and has a confidence interval separated from zero. The secondary estimates are less decisive, with intervals that include zero. Reading the estimates and intervals together provides a more complete account than treating a p-value as a verdict.

Finally, the record highlights the importance of transparent reporting. The per protocol label, enrollment, arm denominators, and safety denominators describe distinct quantities, but their relationship is not explained. Multiplicity, missing-data procedures, and the original sample-size justification are also not reported. Such details help readers assess the reliability and scope of trial conclusions, even when the main endpoint contrast is clear.

18. 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 registry record identifies the primary analysis as per protocol but does not report the criteria for that population, participant flow, or reasons for exclusions. Enrollment is 171, while the primary arm counts are 65 and 69; the relationship between the enrollment total and analyzed counts is not explained. The safety groups use 80 participants at risk in each arm, and their relationship to the primary population is likewise not reported.

The primary endpoint is a laboratory threshold rather than a direct clinical outcome. The record does not state why the threshold was selected or provide the underlying concentration distributions. The full maintenance dosing instructions are truncated in the registry description. Details of the original sample-size justification, statistical analysis plan, missing-data handling, multiplicity control, and interim analyses are not reported in the registry record.

Numerical results are not reported for all of the listed secondary outcomes. The available secondary comparisons are unadjusted, and the record does not describe a testing hierarchy or adjustment for multiple outcomes. Event counts for urgent-care visits are limited, which makes that estimate uncertain. The safety summary is also descriptive and does not provide a detailed causal assessment or comparative uncertainty estimates.

Finally, the registry says the study was single or multi-center but does not report the actual center configuration. These reporting limitations restrict assessment of the analysis and the generalizability of the findings, without changing the posted endpoint counts themselves.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Safety and Efficacy of Rayaldee for Treating Mild to Moderate COVID-19 — NCT04551911.
• Registry record last updated 2024-05-28; status last verified 2024-05.
• Results first posted 2024-05-28.
• 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.

22. Record Summary

REsCue is a completed phase 2 randomized, parallel, double-blind, placebo-controlled study of Rayaldee in adults with symptomatic mild to moderate COVID-19 who tested positive for SARS-CoV-2. The registry reports 171 enrolled participants. Its primary endpoint is attainment of serum total 25-hydroxyvitamin D at or above 50 ng/mL at Day 14 in the per protocol population.

The primary counts are 51 of 65 for Rayaldee and 10 of 69 for placebo, with an unadjusted risk difference of 0.640 and a 95% confidence interval from 0.510 to 0.770. The result concerns the biochemical threshold; secondary symptom and health-care-use outcomes are distinct. The registry record does not report several details needed to fully assess the analysis, including the original sample-size justification, missing-data methods, and multiplicity plan.