Sculptra for Correction of Midface Volume Deficit and/or Midface Contour Deficiency: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sculptra for Correction of Midface Volume Deficit and/or Midface Contour Deficiency (NCT04132518), a randomized na study. The primary outcome is Percentage of Participants With 1 Point Improvement From Baseline on the Medicis Midface Volume Scale (MMVS) as Measured by the Blinded Evaluator at Month 12.

2. Clinical Question

The clinical question is whether participants assigned to Sculptra were more likely than participants assigned to no treatment to have a one-point improvement on the Medicis Midface Volume Scale (MMVS) by Month 12, as rated by a blinded evaluator. The registry also lists other measures, including ratings by treating investigators, midface volume change, global aesthetic improvement, and participants’ views of the result.

The registry describes the study as randomized, multi-center, evaluator-blinded, and no-treatment controlled. It lists 205 participants enrolled. The primary endpoint focuses on change from baseline, rather than a single rating at Month 12, and uses the same scale to assess the right and left midface at applicable study visits. The posted results compare the Sculptra groups with the no-treatment control for the primary outcome.

3. Trial Design

This was a randomized, parallel-group study with single masking, described in the official title as evaluator-blinded. The control condition was no treatment. The listed intervention was Sculptra, classified in the registry as a device. The phase is listed as NA. The study status is completed, and the registry lists 205 participants enrolled.

The record describes three outcome groups: Group A: Sculptra, Group B: Sculptra, and Group B: Control. Participants in both Sculptra groups could receive up to 4 injections beginning on Day 1, at intervals of 5 (±1) weeks and at least 4 weeks apart. Both treatment-group descriptions state that follow-up lasted 24 months. Participants in the Group B control condition received no treatment and were followed for 12 months. The registry does not report the reason for having two Sculptra groups or the distinction between them.

The study start date is 2019-11-12, and the primary completion date is 2021-07-18. The primary outcome was assessed at Month 12, using the MMVS rating made by a blinded evaluator. The record also lists secondary outcomes involving ratings by the treating investigator, volume change, global aesthetic improvement, and participant-reported views of improvement and naturalness.

The primary outcome population is described as the full analysis set (FAS), including Group B participants treated with Sculptra or randomized to no treatment, and Group A participants treated with Sculptra. The registry record does not report the original sample-size justification, the detailed randomization procedure, or the allocation ratio. The planning illustrations described with the posted results are not the trial’s original design assumptions.

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 16 participants were enrolled into Group A and 189 participants were enrolled into Group B. Out of 189 participants in Group B, 126 participants randomized in treatment group and 63 participants in control group or no treatment group.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: FAS included all participants in Group B who were treated with Sculptra or randomized to no-treatment group and participant in Group A who were treated with Sculptra.

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: Full analysis set (FAS) included all participants in Group B who were treated with Sculptra or randomized to no-treatment group and participant in Group A who were treated with Sculptra.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With 1 Point Improvement From Baseline on the Medicis Midface Volume Scale (MMVS) as Measured by the Blinded Evaluator at Month 12, measured over Baseline, Month 12.

The primary endpoint is the percentage of participants with a one-point improvement from baseline on the Medicis Midface Volume Scale (MMVS), measured by a blinded evaluator at Month 12. Improvement means a decrease of one grade in score. The scale has four grades, ranging from fairly full midface to substantial loss of fullness, with higher scores representing more severe volume deficiency. The evaluator and treating investigator rated the right and left midface at applicable visits.

The endpoint turns a clinician-rated scale into a binary outcome: a participant either meets the one-point improvement definition or does not. Reporting the percentage meeting that definition gives a direct description of how many participants crossed the prespecified improvement threshold, rather than describing only an average score change. It also allows the Sculptra groups’ percentages to be compared with the no-treatment group’s percentage.

As a general statistical point, a binary endpoint can be easy to interpret, but it does not show the full range of score changes. A participant with a larger improvement and a participant with exactly a one-point decrease both count as meeting the threshold. The posted primary outcome therefore answers a specific question about the proportion meeting the defined improvement criterion; it does not, by itself, describe every change in severity or the magnitude of improvement beyond that threshold.

7. Results Posted in the Registry

• Group A: Sculptra: 68.8% (11/16) versus 1.6% (1/63) on control; risk difference 67.2 percentage points (95% CI 44.2 to 90.1), risk ratio 43.31 (6.03–311.27); unadjusted two-proportion z-test p = <0.001.
• Group B: Sculptra: 69.4% (86/124) versus 1.6% (1/63) on control; risk difference 67.8 percentage points (95% CI 59.1 to 76.4), risk ratio 43.69 (6.23–306.45); unadjusted two-proportion z-test p = <0.001.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary because each participant is classified according to whether the specified one-point MMVS decrease occurred by Month 12. For a binary outcome, a percentage estimates the proportion of participants meeting the criterion in a group. The reported arm percentages are 68.8% for Group A: Sculptra, 69.4% for Group B: Sculptra, and 1.6% for Group B: Control.

What does a risk difference express?

A risk difference subtracts the outcome proportion in one group from the outcome proportion in another. It remains on the absolute probability scale, which makes it a direct way to express the gap between groups. The unadjusted recalculated risk difference for Group A versus control is 0.672, with a 95% confidence interval from 0.442 to 0.901. For Group B versus control, it is 0.678, with a 95% confidence interval from 0.591 to 0.764. These are unadjusted summaries, not estimates adjusted for baseline characteristics or other covariates.

As a general statistical explanation, a risk difference is distinct from a risk ratio or odds ratio. A risk ratio compares proportions as a ratio; an odds ratio compares odds. Ratios can look large when one group has a low event proportion, so absolute and relative measures answer different questions. The registry record includes ratio summaries, but the interpretation above emphasizes risk differences because they directly describe the absolute gap in improvement proportions.

What does the confidence interval add?

A confidence interval describes uncertainty around an estimate under the statistical procedure used to construct it. In repeated samples, intervals formed by the same method would have a stated coverage property. For an individual trial, an interval gives a range of values compatible with the data and method, rather than a guarantee that the true value lies within that particular interval. The arm-level intervals are 95% confidence intervals, as are the intervals attached to the risk differences.

The interval width depends in part on the amount of information in the data. As a general principle, estimates based on fewer participants are often less precise, all else being equal. Here, the Group A comparison has 16 treated participants and a wider risk-difference interval than the Group B comparison, which has 124 treated participants. The control denominator is 63 in both comparison summaries. This pattern is consistent with the smaller treatment group contributing more uncertainty, though the interval width also depends on the outcome proportions and calculation method.

How should the p-values be read?

The posted unadjusted p-values are p < 0.001 for both treatment-versus-control comparisons. In general, a p-value measures how incompatible the observed data are with a specified null hypothesis, given the statistical model. It is not the probability that the null hypothesis is true, and it does not measure the size of an effect. The risk differences and their intervals provide information about magnitude and precision that the p-values do not convey on their own.

The record does not report the original statistical analysis plan or the exact method used for the registry’s posted interval estimates. It also does not report whether baseline adjustment, stratification, or other modeling was used for the trial’s own analysis. The comparison values are unadjusted recalculations from the posted summary statistics, rather than evidence of a more elaborate model.

Why might over-dispersion matter?

General explanation: over-dispersion occurs when the observed variability in data exceeds what a statistical model assumes. If a model underestimates variability, standard errors can be too small and confidence intervals too narrow. This issue is especially relevant to some count-data models. The primary endpoint is a binary percentage, and the registry record does not report an over-dispersion assessment or a model that would permit one to be evaluated. It should not be assumed that such a correction was or was not used in the trial’s original analysis.

The scale itself is ordinal: its grades have a natural order from fuller midface to greater loss of fullness, but the distance between adjacent grades is not necessarily equal. The primary endpoint avoids treating the entire scale as a continuous measure by defining success as a one-grade decrease. That makes the criterion interpretable, while also discarding information about changes that do not meet the threshold or changes beyond one grade.

Randomization is intended, in general, to make treatment groups comparable on average and to reduce systematic allocation bias. The registry identifies the study as randomized, but the detailed randomization sequence, concealment procedures, and any stratification are not reported in the registry record. Evaluator blinding is stated in the official title, which is relevant because the primary outcome depends on a visual severity rating. The record lists masking as single but does not provide further detail about who was masked.

10. Confidence Intervals and Precision

Precision is reflected by the width of the confidence interval: narrower intervals indicate less statistical uncertainty under the method used. For the primary arm-level percentages, the 95% confidence intervals are 41.3% to 89.0% for Group A: Sculptra, 60.4% to 77.3% for Group B: Sculptra, and 0.0% to 8.5% for Group B: Control. The Group A interval is visibly broad, consistent with the relatively small treatment denominator of 16. The Group B treatment estimate is more precise, with 124 participants in the comparison summary.

For Group A versus control, the risk difference is 0.672 and its 95% confidence interval is 0.442 to 0.901. For Group B versus control, the risk difference is 0.678 and its interval is 0.591 to 0.764. Both intervals indicate uncertainty around the estimated absolute difference, and the Group A interval covers a wider range of possible values. Confidence intervals do not resolve uncertainty about bias, generalizability, or whether the analysis method matches the trial’s original plan.

As a general statistical principle, precision depends on the number of observations, the observed event proportion, and the method used to construct the interval. A larger sample often improves precision, but it does not remove all sources of uncertainty. The registry record does not report the interval construction method, missing-data handling, or an adjusted estimate that could be compared with the unadjusted results. The intervals should therefore be interpreted as uncertainty summaries for the posted results, not as proof that all relevant uncertainty has been captured.

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 sample-size planning figures are participants per arm for 80% power and participants per arm for 90% power. They are planning illustrations based on the observed risk difference, not the trial’s original design assumptions. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the stated share of the observed effect. These figures are participants per arm, not totals across arms; the time-to-event convention of total number of events does not apply to this binary outcome.

For each treatment-versus-control comparison, the planning display considers 100%, 75%, and 50% of the observed effect. At 100% of the observed effect, the estimate is 7 participants per arm for 80% power and 9 for 90% power for both comparisons. At 75%, the Group A comparison gives 11 participants per arm for 80% power and 15 for 90% power; the Group B comparison gives 11 and 14, respectively. At 50%, both comparisons give 20 participants per arm for 80% power and 26 for 90% power.

In plain language, the 80% column represents the planned chance of detecting the stated effect if the assumptions hold, while the 90% column represents a higher planned chance of detection under those assumptions. Smaller effects need more participants, which is why the figures rise as the planning effect moves from the full observed effect to a smaller share. These calculations are not observed power. They are not evidence that the original study was designed using these assumptions, and the trial’s own sample-size justification is not reported in the registry record.

The curve should be read as a planning illustration of how the required group size changes as the effect to detect changes, not as an additional observed trial result. Its values depend on the stated assumptions and the particular outcome proportions used in the recalculation. A planning estimate is not a guarantee that a future study will attain a given precision or detect an effect.

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 = 0.016; treatment proportion p₁ = 0.688; average p̄ = 0.352.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6753 = 1.3235.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.4801 = 0.4040.
4. n = (1.3235 + 0.4040)² / (0.6716)² = 6.6, rounded up to 7 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 <- 0.0158730158730159                          # control proportion
p1 <- 0.6875                          # 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(4132518)
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 = 7 (80% power), 9 (90% power)
 75% of observed effect: n per arm = 11 (80% power), 15 (90% power)
 50% of observed effect: n per arm = 20 (80% power), 26 (90% power)
power.prop.test: 6.6 
Simulated power at n = 7 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.

13. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and multiple secondary outcomes. These include MMVS improvement rated by the treating investigator, total volume change over time, global aesthetic improvement assessed by the treating investigator and participant, and participant agreement about improvement, natural appearance, and whether expectations were met or surpassed. The record lists 16 outcome measures and 15 posted secondary outcomes.

When a study evaluates several outcomes, time points, or comparisons, the chance of at least one apparently unusual result can increase if each is tested separately without an adjustment strategy. General statistical methods for addressing multiplicity include defining a primary outcome in advance, controlling an overall error rate, or treating secondary analyses as exploratory. The registry record does not report the trial’s multiplicity plan or whether any adjustment was used. The displayed p-values are unadjusted, so they should not be interpreted as multiplicity-adjusted evidence.

The record identifies the primary analysis population as the FAS and describes which participants it includes: Group B participants treated with Sculptra or randomized to no treatment, and Group A participants treated with Sculptra. It does not provide a fuller definition of how participants were handled if they did not receive assigned treatment, missed visits, or had incomplete measurements. The handling of missing data, withdrawals, and deviations from assigned treatment is not reported in the registry record.

It is also not reported whether the primary analysis followed intention-to-treat principles, how many participants contributed outcome data at Month 12, or whether sensitivity analyses were performed. The endpoint summaries list denominators of 16, 124, and 63 in the comparison data, but the record does not explain whether these are the full randomized groups or the participants with available Month 12 assessments. This distinction matters because exclusions or missing assessments can affect the comparability created by randomization.

The original statistical analysis plan, prespecified covariate adjustments, interim analyses, and stopping rules are not reported in the registry record. These omissions limit assessment of how closely the posted outcome results match the original planned analysis and how the many outcomes were handled.

14. 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: lumbar vertebral fracture (6.2%), meningioma (6.2%), thrombocytosis (0.8%), abortion spontaneous (0.8%), ovarian cyst (0.8%).

The serious adverse event figures report 2 affected participants among 16 at risk in Group A: Sculptra, 7 among 124 in Group B: Sculptra, and 0 among 63 in Group B: Control. The record reports 0 deaths in each group. These counts describe the listed safety groups; they do not, by themselves, establish that an event was caused by study treatment.

For other adverse events, the record reports 10 affected participants among 16 in Group A: Sculptra, 15 among 124 in Group B: Sculptra, and 4 among 63 in Group B: Control. These are separate figures from the serious adverse event counts. The registry also lists serious-event terms with percentages: lumbar vertebral fracture, 6.2%; meningioma, 6.2%; thrombocytosis, 0.8%; abortion spontaneous, 0.8%; ovarian cyst, 0.8%; and removal of internal fixation, 0.8%.

The listed terms do not identify group attribution in the information, and the percentages should not be treated as a comparison between groups. The registry record does not provide further detail on event timing, relatedness assessments, or how events were categorized beyond the listed serious and other adverse event counts. Safety counts are descriptive and should be interpreted with the denominators and reporting limitations in mind.

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

The primary result describes a higher percentage meeting the one-point MMVS improvement criterion in each Sculptra group than in the no-treatment control group at Month 12. The posted percentages are 68.8% in Group A: Sculptra, 69.4% in Group B: Sculptra, and 1.6% in Group B: Control. The unadjusted recalculated risk differences are 0.672 and 0.678 for the Group A and Group B comparisons with control, respectively, and both have p < 0.001.

These statistics describe the observed participants and the defined endpoint. They do not, by themselves, establish that every participant experienced improvement, describe the degree of change among those who improved, or represent all outcomes assessed in the study. The endpoint counts a one-point decrease as improvement; it does not distinguish that change from a larger decrease. Other secondary measures address different aspects of ratings, volume, and participant perceptions.

The confidence intervals express statistical uncertainty in the estimates. The wider interval for Group A reflects less precision than the Group B estimate, while neither interval captures possible bias from missing data, outcome measurement, or choices in analysis. The record does not report enough information to evaluate missing-data methods or the original analysis plan. The reported p-values are unadjusted, and the registry record does not report how multiplicity across outcomes was handled.

The no-treatment comparator provides a reference for the primary comparison, but the record does not report the detailed masking arrangements beyond single masking and the evaluator-blinded description. Whether participants were masked is not reported in the registry record. This may be relevant when interpreting participant-reported secondary outcomes, which can be sensitive to expectations. It does not change the definition of the blinded evaluator-rated primary endpoint, but it is part of the wider context for reading the results.

These results are not medical advice and should not be read as a recommendation for an individual. They are a statistical description of the posted trial outcome, its uncertainty, and the limits of the registry detail.

16. Why This Trial Matters Statistically

This study illustrates how a clinically defined rating scale can be converted into a binary endpoint. The MMVS has ordered severity grades, and the primary definition classifies a one-grade decrease as improvement. That definition is easy to state and produces an interpretable percentage, but it necessarily simplifies the range of possible changes. Statistical interpretation should remain tied to that precise endpoint rather than treating it as a complete account of facial volume or participant experience.

The results also show why effect estimates and confidence intervals are useful alongside p-values. Both unadjusted comparisons have p < 0.001, but the risk differences and their intervals communicate the size and precision of the observed group separation. The smaller Group A comparison has a wider interval than the Group B comparison, highlighting how group size affects the stability of an estimate.

Another important statistical feature is the presence of multiple outcome measures and assessors. The registry lists both evaluator and treating-investigator ratings, measures of volume change, and participant-reported assessments. Those outcomes are related but not interchangeable. The missing report of a multiplicity plan and detailed missing-data procedures limits a full assessment of how the complete set of findings should be interpreted.

Finally, the sample-size illustrations show how planning depends on the effect one wishes to detect. They use the observed result as a basis for hypothetical planning, with smaller effects requiring more participants. They should not be confused with the trial’s original design justification. The distinction between retrospective planning illustrations and prospective design assumptions is important whenever sample-size figures accompany completed-trial results.

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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

The registry record does not report the original sample-size justification, the detailed randomization procedure, or the trial’s statistical analysis plan. It also does not specify whether the reported primary comparisons were adjusted for baseline characteristics or other variables. As a result, the posted unadjusted recalculations cannot be compared with an independently described primary analysis protocol.

The primary outcome has a dichotomous threshold: a one-point decrease is counted as improvement. The summary does not show the distribution of MMVS score changes beyond that classification. The Month 12 endpoint also does not capture the full follow-up duration described for the treatment groups. Although treatment participants were followed for 24 months, the primary outcome is at Month 12; the record does not provide a comparable longer-term control outcome in these results.

The control group was followed for 12 months, while the Sculptra group descriptions state 24 months of follow-up. The registry record does not explain the rationale for this difference or the distinction between Group A and Group B treatment groups. The comparison denominators are 16, 124, and 63, but the record does not state how missing Month 12 data, withdrawals, or protocol deviations were handled.

Masking is listed as single, and the study is described as evaluator-blinded. The identity of other masked parties is not reported in the registry record. The study includes multiple secondary outcomes, but the multiplicity strategy is not reported. The record also does not provide detailed adverse-event timing, relatedness, or group attribution for the listed serious-event terms. These limits constrain interpretation of both outcome and safety summaries.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Sculptra for Correction of Midface Volume Deficit and/or Midface Contour Deficiency — NCT04132518.
• Registry record last updated 2025-01-07; status last verified 2024-01.
• Results first posted 2024-12-19.
• 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

The registry describes a completed randomized, parallel-group, single-masked, evaluator-blinded, no-treatment controlled study of Sculptra for midface volume deficit and/or midface contour deficiency. Enrollment is listed as 205. The study started on 2019-11-12, with primary completion on 2021-07-18, and phase is listed as NA.

The primary outcome was the percentage with a one-point improvement from baseline on the MMVS at Month 12, rated by a blinded evaluator. The posted percentages were 68.8% for Group A: Sculptra, 69.4% for Group B: Sculptra, and 1.6% for Group B: Control. The unadjusted recalculated risk differences versus control were 0.672 and 0.678, with p < 0.001 for both comparisons.

The record lists additional aesthetic, volume, and participant-reported outcomes, alongside serious and other adverse event counts. The original sample-size justification, detailed analysis plan, multiplicity approach, and missing-data procedures are not reported in the registry record.