Safety Study of AEM-28 to Treat Refractory Hypercholesterolemia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety Study of AEM-28 to Treat Refractory Hypercholesterolemia (NCT02100839), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants Who Incurred at Least One Treatment Emergent Event.

2. Clinical Question

The registry record presents a study spanning healthy subjects with high total cholesterol and patients with refractory hypercholesterolemia. Its stated purpose was to evaluate safety and tolerability alongside pharmacokinetics and pharmacodynamics. The primary endpoint focuses on treatment-emergent events, while the safety description also lists vital signs, electrocardiograms, telemetry, laboratory parameters, physical examinations, local injection response, and body weight in Part B.

The central statistical question is descriptive: how many participants in each group experienced at least one treatment-emergent event over the designated observation period? The endpoint counts people rather than the total number of events. A participant with multiple events still contributes to the participant count as having incurred at least one event. The posted results do not provide event counts by participant or further breakdowns of event type, severity, or relationship to study medication for this primary outcome.

The comparison is between AEM-28 and normal saline, but the study also has separate single-dose and multiple-dose parts and multiple dose levels. The registry record does not report the group-level allocation across those parts and dose cohorts for this outcome. Consequently, the posted summary does not establish how much the overall counts reflect the different study parts, doses, or participant populations.

3. Trial Design

The registry record identifies NCT02100839 as a Phase 1 and Phase 2 study titled “Safety Study of AEM-28 to Treat Refractory Hypercholesterolemia.” It lists randomized allocation and quadruple masking, while the study model is recorded as single group. These registry classifications are not fully reconciled by the record, so the design should be described with that qualification rather than assuming a more specific allocation structure.

The official title describes a randomized, double-blind, placebo-controlled study evaluating safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple ascending doses of AEM-28 in healthy subjects and patients with refractory hypercholesterolemia. The intervention listings identify AEM-28 and normal saline. The record describes Part A as a single ascending dose evaluation in healthy subjects with high total cholesterol and Part B as a multiple ascending dose evaluation in patients with refractory hypercholesterolemia.

In Part A, each AEM-28 cohort received a single intravenous dose, with the stated dose range of 0.032 mg/mL to 3.54 mg/mL; normal saline cohorts also received a single intravenous dose. In Part B, each AEM-28 cohort received three intravenous doses, one every two weeks, with a stated dose range of 1 mg/kg to 3.54 mg/kg. The normal saline description specifies the same dosing schedule for the multiple ascending dose cohorts. Further details about dose escalation decisions, cohort sizes, or assignment to dose levels are not reported in the registry record.

The registry record lists enrollment as 52 and status as completed. The recorded study start is 2014-03 and primary completion is 2014-11. These dates describe the record and do not establish when every analysis was performed. The primary outcome is a participant count for treatment-emergent events. The analysis description says safety and tolerability data were reported using descriptive statistics. The registry record does not report a detailed statistical analysis plan or the planned allocation ratio.

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.

Single Ascending Dose

Multiple Ascending Dose

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Who Incurred at Least One Treatment Emergent Event, measured over Part A (SAD): Day -1 to Day 15; Part B (MAD): Day 1 to Day 57.

The primary endpoint is the number of participants who incurred at least one treatment-emergent event. It is a participant-level safety measure: the outcome indicates whether a person experienced an event during the relevant observation period, not how many events that person experienced. The timeframe is Part A (SAD): Day -1 to Day 15; Part B (MAD): Day 1 to Day 57.

This measure is used to summarize the proportion of each treatment group with any treatment-emergent event and to support a descriptive account of safety and tolerability. In this study, that broad count is complemented in the outcome description by assessments of seriousness, severity, relationship to study medication, outcome, duration, and management. The description also lists vital signs, 12-lead ECG, telemetry, clinical laboratory parameters, physical examination, local response to each injection, and body weight in Part B.

The posted primary results give 33 participants with an event among 37 in the AEM-28 group and 10 among 15 in the normal saline group. Those counts do not convey the number of events, their clinical characteristics, or whether they were judged related to treatment. The registry record does not post a breakdown of the primary endpoint by study part or dose cohort. As a result, the overall participant counts should be read as a broad safety summary rather than a detailed account of individual event patterns.

For safety outcomes, descriptive counts can identify how frequently participants experienced at least one event, but they do not by themselves establish causality. Interpretation also depends on event definitions, ascertainment, exposure, follow-up, and the characteristics of the groups. Those details are not fully reported in the registry record.

7. Results Posted in the Registry

• Normal Saline: 66.7% (10/15) versus 89.2% (33/37) on control; risk difference -22.5 percentage points (95% CI -48.4 to 3.3), risk ratio 0.75 (0.51–1.09); unadjusted two-proportion z-test p = 0.052.

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count measure?

The primary outcome is a count of participants who experienced at least one treatment-emergent event. General statistical explanation: a binary participant-level outcome classifies each person as having or not having the outcome during the defined observation period. It does not count repeat events as additional participants. Thus, 33 participants with an event in the AEM-28 group does not mean that only 33 events occurred; the total number of events is not reported for this endpoint.

The record describes safety and tolerability data as being reported using descriptive statistics. This fits a safety summary that presents counts and group sizes. The resulting group-level proportions are useful for describing what was observed, but a simple summary does not adjust for differences between participants or for the separate parts and dose cohorts. The registry record does not report whether the primary comparison was part of a prespecified inferential analysis.

How should the unadjusted contrast be understood?

The risk difference expresses the difference between the participant-level event risks in the two groups. The reported contrast is for normal saline relative to AEM-28: -0.225. General statistical explanation: a negative risk difference means the observed event risk in the group named in the contrast is lower than in its reference group. This describes the direction of the estimate, not proof that treatment caused the difference.

The unadjusted confidence interval for the risk difference is -0.484 to 0.034. It conveys uncertainty around the estimated contrast based on the posted summary statistics. Because its range includes no difference and extends into a small positive contrast, it does not pin down the direction with precision. The unadjusted p-value is 0.052. A p-value measures how compatible the observed data are with a specified null model under the test’s assumptions; it is not the probability that the null hypothesis is true, nor a measure of clinical importance. The registry record does not report the test procedure or full analysis plan.

The comparison also reports a risk ratio of 0.748 with interval 0.514 to 1.088, and an odds ratio of 0.242 with interval 0.054 to 1.079. These are alternative ways to describe the group contrast. A risk ratio compares event risks, while an odds ratio compares event odds. They have different scales and should not be read as interchangeable measures. Both intervals span the value corresponding to no contrast, indicating uncertainty about the direction and magnitude. These summaries are unadjusted.

Why does over-dispersion matter?

General statistical explanation: over-dispersion arises when observed variability is greater than a statistical model expects. It is especially relevant to counts of events, where a small number of participants may experience repeated events. Treating every event as independent can then understate uncertainty. The primary outcome counts participants with at least one event, not total events, and the posted result does not provide repeated-event counts. The registry record does not report a dispersion parameter or an analysis that models event counts, so an over-dispersion assessment is not available from this outcome summary.

Even for a participant-level binary outcome, uncertainty depends on the number of participants and on how the trial was conducted. The record lists randomized allocation and quadruple masking, but also labels the model single group. It does not explain that combination or report allocation details. The reported unadjusted comparison should therefore be interpreted as a contrast between the posted group summaries, rather than as evidence that all design features or potential sources of variation were incorporated into a model.

What role do confidence intervals play?

General statistical explanation: a confidence interval gives a range of estimates reasonably compatible with the data and the method used to calculate the interval. It is more informative than a point estimate alone because it indicates precision. A broad interval signals that the data allow a wide range of possible contrasts. The interval does not include every uncertainty, such as possible bias from outcome ascertainment, selection, missing data, or limitations in the analysis model.

Here, the risk-difference interval is broad relative to the point estimate and extends across no difference. The intervals for the risk ratio and odds ratio also span their no-contrast values. These results do not establish equivalence or absence of an effect; they show that the posted summary does not precisely distinguish among a range of possible contrasts. The registry record does not state a confidence level for the reported intervals.

What does the analysis record leave unresolved?

The primary outcome description says safety and tolerability data were reported with descriptive statistics, but the registry record does not report the analysis population, treatment of missing outcome data, a missing-data strategy, or an adjusted analysis. It also does not report multiplicity procedures for the several safety assessments and listed outcomes. These details matter because multiple outcomes or comparisons can affect the interpretation of isolated statistical results, and missing observations can affect the group summaries.

The study has single ascending dose and multiple ascending dose parts, a range of AEM-28 doses, and different participant populations. The record does not post the primary endpoint results separately by these features. The overall comparison cannot therefore establish whether event patterns varied by dose, part, or population. Nor can it determine whether the groups had comparable exposure or follow-up beyond the stated timeframes. Those questions require information not reported in the registry record.

10. Confidence Intervals and Precision

The risk-difference estimate for normal saline relative to AEM-28 is -0.225, with a confidence interval from -0.484 to 0.034. This interval is wide and crosses no difference, so the point estimate should not be read as a precise description of the contrast. The data are compatible with a range of possible differences, including a modest contrast in the opposite direction from the point estimate.

The risk ratio is 0.748, with interval 0.514 to 1.088. The odds ratio is 0.242, with interval 0.054 to 1.079. These measures use different scales, but each interval spans its no-contrast value. The estimates and intervals do not establish a clear direction for the group difference. The unadjusted p-value is 0.052; it is a test summary, not a measure of precision or practical importance by itself.

General statistical explanation: confidence intervals reflect sampling uncertainty under the assumptions of the calculation. They do not correct for unreported differences in dose cohort, study part, participant characteristics, outcome assessment, or missingness. The registry record does not state the confidence level or provide a more detailed interval method. The limited group sizes and the absence of stratified results constrain how much can be concluded from the overall comparison.

The serious adverse event counts are zero affected participants in each group, but zero observed participants with a serious event does not establish that the underlying risk is zero. Precision for rare outcomes depends on the amount of relevant observation and the analysis method; those details are not fully reported in the registry record. Deaths are not reported in the registry record.

11. 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 planning figures are participants per arm, not total events. The assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as a stated fraction of the observed effect. The original trial’s own design assumptions, including its sample-size justification, are not reported in the registry record.

For planning at 100% of the observed effect, the figures are 53 participants per arm for 80% power and 70 participants per arm for 90% power. For planning at 75% of the observed effect, they are 85 participants per arm for 80% power and 113 participants per arm for 90% power. For planning at 50% of the observed effect, they are 169 participants per arm for 80% power and 226 participants per arm for 90% power.

In plain language, the 80% power column gives an illustrative group size intended to provide an 80% chance of detecting the chosen effect under the stated assumptions if that effect were present. The 90% power column gives the corresponding planning size for a higher chance of detection. These are planning illustrations, not observed power.

The effect fractions describe how large a future effect is assumed to be relative to the observed effect. Smaller effects require more participants to detect under the same assumptions, which is why the planning figures increase as the assumed fraction decreases. The figures are not the enrollment target used for this study and do not show that the trial was designed to detect these contrasts. The registry record does not report the trial’s own sample-size rationale or its original power target.

12. 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 = 0.892; treatment proportion p₁ = 0.667; average p̄ = 0.779.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5865 = 1.1496.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5645 = 0.4751.
4. n = (1.1496 + 0.4751)² / (-0.2252)² = 52.0, rounded up to 53 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 <- 0.891891891891892                          # control proportion
p1 <- 0.666666666666667                          # 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(2100839)
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 = 53 (80% power), 70 (90% power)
 75% of observed effect: n per arm = 85 (80% power), 113 (90% power)
 50% of observed effect: n per arm = 169 (80% power), 226 (90% power)
power.prop.test: 52 
Simulated power at n = 53 per arm: 0.827 (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.

13. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary safety endpoint and one secondary outcome, VLDL-C percent change. It also describes several safety assessments, including adverse-event characteristics, vital signs, electrocardiograms, telemetry, laboratory parameters, physical examination, local injection response, and body weight in Part B. The record does not report whether the statistical plan adjusted for multiple outcomes, comparisons, dose cohorts, or timepoints. No multiplicity procedure is reported in the registry record.

Multiplicity matters because repeated testing across outcomes or groups can make an isolated result appear more notable than it would be under a single prespecified test. General statistical explanation: adjustment procedures can control the chance of false-positive findings across a family of tests, while other approaches may instead treat results as exploratory. Without a reported plan, the status of the unadjusted comparison within any wider testing strategy is unclear. The unadjusted p-value should not be interpreted as evidence that multiplicity was addressed.

The registry record does not report missing-data counts, reasons for missingness, imputation, or a sensitivity analysis. It therefore does not establish whether all enrolled participants contributed to the primary endpoint or how any unavailable observations were handled. This matters because the displayed group counts and denominators describe the posted result, but do not by themselves explain the analysis population or missing-outcome procedures.

The record also does not report whether analyses followed an intention-to-treat, per-protocol, safety, or other defined population. It does not describe exclusions after randomization or how participants who received different doses were represented in the summary. As the study includes separate parts, different participant populations, and ascending doses, those choices could affect interpretation. Their details are not reported in the registry record.

Finally, no interim-analysis plan, stopping rule, or detailed statistical analysis plan is reported in the registry record. Their absence from the record should not be taken as proof that none existed; it means their methods cannot be assessed from the posted information.

14. Safety Results

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

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The serious adverse event figures report zero affected participants among 37 at risk in the AEM-28 group and zero among 15 at risk in the normal saline group. No serious event terms are listed. These figures are distinct from the primary endpoint, which counts participants with any treatment-emergent event and reports 33 in the AEM-28 group and 10 in the normal saline group.

A zero count means that no participant with a serious adverse event is recorded in these posted figures. It does not establish that the underlying risk is zero, and the small group sizes limit precision about uncommon events. The record does not provide further detail about serious-event surveillance or follow-up beyond the stated primary outcome timeframes.

The deaths field is not reported in the registry record. It should not be interpreted as a reported zero. The lack of listed serious-event terms means no terms are posted in that summary; it does not provide information about non-serious events, event severity, or treatment relationship. Those features were included in the stated safety assessment, but their detailed results are not reported in the primary summary.

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

The posted results describe treatment-emergent events among participants in the AEM-28 and normal saline groups during the stated study periods. The broad primary count records 33 participants with at least one event among 37 in the AEM-28 group and 10 among 15 in the normal saline group. The unadjusted risk difference is -0.225, with an interval from -0.484 to 0.034 and p = 0.052. The estimate favors a lower observed event frequency in the normal saline group, but the interval is compatible with a range of contrasts and crosses no difference.

These results do not establish that AEM-28 caused more events, that normal saline caused fewer events, or that the treatments are equivalent. The unadjusted comparison does not account for the separate parts, doses, or participant populations in the information reported. The registry record does not provide a detailed analysis plan, subgroup results, or enough information to assess all sources of bias and uncertainty.

The primary endpoint is an overall participant count, not a measure of event severity, recurrence, duration, or clinical consequence. Although the safety description says these characteristics were assessed, detailed results are not reported in the primary outcome summary. The serious adverse event figures show zero affected participants in both groups, but deaths are not reported in the registry record.

The study’s stated aims include pharmacokinetics and pharmacodynamics, and the record lists VLDL-C percent change as a secondary outcome. The posted information summarized by the primary result does not establish a lipid-lowering effect, a dose-response relationship, or longer-term outcomes. The statistical findings should be read as a limited descriptive comparison of the registry’s posted safety counts, not as a clinical recommendation or a definitive assessment of treatment benefit or harm.

16. Why This Trial Matters Statistically

This study illustrates why safety results need to be read at the level of the outcome definition. The primary endpoint counts participants with at least one treatment-emergent event, whereas serious adverse event figures count participants with serious events. The posted primary counts are much broader than the serious-event summary in scope; the two should not be treated as contradictory measures of the same outcome.

It also illustrates the value of presenting an estimate with an interval. The risk-difference point estimate is -0.225, but the interval from -0.484 to 0.034 indicates substantial uncertainty and includes no difference. The unadjusted p-value of 0.052 alone would not convey the range of contrasts compatible with the data. Alternative relative measures also have intervals spanning no contrast.

The design has features that make interpretation especially dependent on details: healthy subjects in Part A, patients with refractory hypercholesterolemia in Part B, single and multiple ascending dose schedules, and several dose levels. The registry record does not provide outcome breakdowns by these dimensions. This shows why an overall summary may be insufficient for understanding whether safety patterns differ across populations or exposure schedules.

Finally, the planning illustrations show how assumptions about the effect to detect influence required group sizes. They are not evidence of the study’s original design intent or of observed power. Distinguishing a planning calculation from a trial’s prespecified design is important when using registry results to inform future studies.

17. 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 gives an overall primary endpoint summary without results separated by Part A and Part B, dose cohort, or dose level. The study populations and dosing schedules differ between the parts, so the pooled group counts cannot show whether event patterns varied across those contexts. The record does not provide a breakdown that would allow those differences to be examined.

The outcome is a count of participants with at least one treatment-emergent event. Detailed primary results on event type, severity, seriousness, relationship to study medication, duration, outcome, and management are not posted in the summary. Although the endpoint description says those attributes were assessed, their results are not available. The total number of events is also not reported.

The registry classifications list randomized allocation and quadruple masking, while the model is recorded as single group. The record does not explain this combination or give further allocation details. It does not report group assignment by dose cohort, the analysis population, missing data handling, or adjusted analyses. The unadjusted comparison therefore cannot address potential imbalances or clarify how the separate study parts were represented.

The original sample-size justification and statistical plan are not reported in the registry record. Nor are multiplicity procedures, interim analyses, subgroup analyses, or a confidence level for the intervals. The planning illustrations are based on the observed effect and stated assumptions, not the trial’s own design rationale.

The serious adverse event summary reports zero affected participants in each group, but the deaths field is not reported in the registry record. The record also does not provide longer-term safety outcomes beyond the stated timeframes. These omissions constrain interpretation and should not be replaced by assumptions about unreported data.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Safety Study of AEM-28 to Treat Refractory Hypercholesterolemia — NCT02100839.
• Registry record last updated 2015-12-29; status last verified 2015-03.
• Results first posted 2015-12-29.
• 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.

21. Record Summary

NCT02100839 is a completed Phase 1 and Phase 2 study sponsored by LipimetiX Development, LLC. The record describes randomized allocation and quadruple masking, while also listing a single-group model. The study addressed safety, tolerability, pharmacokinetics, and pharmacodynamics of AEM-28 in healthy subjects and patients with refractory hypercholesterolemia.

Part A evaluated single ascending doses in healthy subjects with high total cholesterol; Part B evaluated multiple ascending doses in patients with refractory hypercholesterolemia. Normal saline was the comparison treatment. The primary outcome counted participants with at least one treatment-emergent event over the part-specific timeframe.

The posted primary counts are 33 of 37 participants for AEM-28 and 10 of 15 for normal saline. The unadjusted risk difference is -0.225, with interval -0.484 to 0.034 and p = 0.052. Serious adverse event figures show zero affected participants in each group; deaths are not reported in the registry record. The record lists VLDL-C percent change as a secondary outcome, but no secondary analysis results are posted in the analysis summary.