A Study Evaluating Desvenlafaxine Sustained Release (DVS SR) in Adult Female Outpatients With Fibromyalgia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study Evaluating Desvenlafaxine Sustained Release (DVS SR) in Adult Female Outpatients With Fibromyalgia (NCT00696787), a randomized phase 2 study. The primary outcome is Change From Baseline on the Numeric Rating Scale (NRS).

2. Clinical Question

3. Trial Design

This was a phase 2, randomized, double-blind, parallel-group study described in its official title as multicenter, placebo-controlled, pregabalin-referenced, and adaptive. It enrolled 125 participants. The registry lists fibromyalgia as the condition and records the study status as terminated. The study started in 2008-06, and primary completion is recorded as 2009-01.

The arm descriptions specify that participants were assigned in the first stage to placebo, DVS SR 200 mg/day, or pregabalin 450 mg/day. Each description states that the sponsor stopped the study after stage 1. The registry record does not report why the sponsor stopped it, or the details of how the adaptive design was intended to operate. The title alone does not establish what design changes or decision rules were planned.

For the primary endpoint, the recorded analysis population was the Modified Intent to Treat population. It required randomization, at least one dose of double-blind study treatment, a baseline primary efficacy evaluation, and at least one primary efficacy evaluation during double-blind treatment. The primary outcome was mean change in the pain score from baseline to the average score during the last data-analysis interval of week 8. The arm-level analysis sizes were 40 for placebo, 42 for DVS SR, and 43 for pregabalin.

The registry lists one secondary outcome, also based on change in the Numeric Rating Scale, and reports two outcome measures and four analyses overall. The original sample-size target, allocation ratio, planned analysis details, and the protocol’s stopping or adaptation rules 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.

Before assignment: After a 7 to 30 day screening period, eligible subjects entered a 7 day single blind placebo run-in period during which placebo responses were assessed.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The Modified Intent to Treat (MITT) population included all randomized subjects who had taken at least one dose of double-blind test article, who had a baseline primary efficacy evaluation, and who had at least one primary efficacy evaluation on double-blind therapy.

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 Change From Baseline on the Numeric Rating Scale (NRS), measured over Baseline and 8 weeks.

The primary endpoint was change from baseline in pain severity measured with an 11-point Numeric Rating Scale. The scale runs from 0, meaning no pain, to 10, meaning the worst possible pain. For the primary outcome, baseline was the average of the scores over the last 7 days of the screening period, just before the placebo run-in. The endpoint value was the average pain score during the last data-analysis interval of week 8.

Change scores put each participant’s follow-up score in relation to their baseline score. A negative mean change indicates that the measured score was lower at the endpoint than at baseline, on average. This makes the outcome a measure of change in reported pain severity rather than a comparison of endpoint scores alone. The registry reports arm means and their standard errors, as well as adjusted comparisons between arms.

Using a defined instrument and assessment period gives the treatment groups a common outcome for comparison. The measure records pain severity, but the registry does not state a threshold for a clinically important difference. Statistical estimates therefore describe the size and uncertainty of observed score differences; they do not, by themselves, determine whether a difference would be meaningful to participants.

7. Results Posted in the Registry

• DVS SR: mean -1.60 versus -1.98 on control; difference 0.38 (95% CI -0.65 to 1.41), standardized effect d = 0.16; z-test p = 0.468.
• Pregabalin: mean -1.70 versus -1.98 on control; difference 0.28 (95% CI -0.76 to 1.32), standardized effect d = 0.12; z-test p = 0.598.

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.

Change From Baseline on the Numeric Rating Scale (NRS) in the Treatment of Pain Associated With Fibromyalgia in Adult Female Outpatients

• 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 errors.
• Result:
  • DVS SR: mean -1.64 versus -2.00 on control; difference 0.36 (95% CI -0.69 to 1.41), standardized effect d = 0.17; z-test p = 0.503.
  • Pregabalin: mean -1.45 versus -2.00 on control; difference 0.55 (95% CI -0.52 to 1.62), standardized effect d = 0.26; z-test p = 0.313.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between DVS SR and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Pregabalin and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists one secondary outcome, another analysis of change in Numeric Rating Scale pain scores, and reports comparisons of each active-treatment group with placebo. Across those comparisons, the estimates are imprecise and the reported confidence intervals include zero. This gives the secondary findings the same broad pattern as the primary endpoint: the posted analyses do not demonstrate a clear separation between either active-treatment group and placebo.

The secondary outcome is related to the primary result because both concern change in pain scores measured on the same scale over the same general baseline-to-week-8 period. It offers another reported analysis of pain change, rather than an independent clinical domain or a separate type of outcome. The record does not explain how the secondary outcome differs substantively from the primary measure beyond its title, or why the secondary analysis has a different analysis population.

Secondary results generally carry less confirmatory weight when they are not part of a clearly reported testing hierarchy or when multiple analyses are considered without a reported adjustment for multiplicity. Repeated testing can make isolated low p-values less persuasive as confirmatory evidence. In this record, the multiplicity strategy is not reported, so the secondary comparisons are best treated as additional descriptive evidence rather than independent confirmation.

The registry describes the overall study as adaptive, but does not provide the planned decision rules, timing of any planned adaptations, or analysis strategy for the stages. It is therefore not possible to determine from the record how the secondary analyses fit into the intended design or whether they were affected by a prespecified selection process. Their interpretation should remain tied to the posted summaries and the limitations of the reporting.

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

• Change From Baseline on the Numeric Rating Scale (NRS) in the Treatment of Pain Associated With Fibromyalgia in Adult Female Outpatients

9. Statistical Interpretation

10. Statistical Methods Explained

What does a mean change represent?

The outcome is continuous: each participant’s rating can take values along the Numeric Rating Scale, and the arm summaries report mean change from baseline. A mean condenses the group’s scores into a single average. It is useful for comparing groups, but it does not show the full distribution of individual responses. The registry record does not report the distribution of scores or the proportion of participants with particular levels of change.

Because the endpoint is a change score, negative values indicate a lower follow-up pain rating than the baseline rating on average. A difference between arm means is a contrast between group averages, not a statement about every participant. Individual outcomes may vary around the group mean.

What does the standard error describe?

The arm summaries report standard errors. A standard error describes the sampling uncertainty around an estimated mean: it reflects how much the estimate would tend to vary across comparable samples under the statistical model. It is not the same as a standard deviation, which describes variation among participant-level measurements. The registry does not report arm-level standard deviations for this endpoint. The unadjusted recalculations use pooled standard deviations derived for those calculations, but those values are not substitutes for the reported standard errors or for individual-level data.

Standard errors help quantify precision of a mean estimate, but they do not capture every source of uncertainty. In particular, a standard error does not resolve questions about missing outcomes, selection into the analysis population, or whether the endpoint and analysis were prespecified. Those details are not fully reported in the registry record.

Why are adjusted and unadjusted comparisons different?

The sponsor reports ANCOVA comparisons as adjusted means. Analysis of covariance compares groups while accounting for one or more covariates in a statistical model. The registry identifies the method as ANCOVA but does not report the covariates, model specification, handling of missing observations, or other implementation details. It is therefore possible to describe the method named in the record, but not to reconstruct its full model from the posted summary.

The recalculated comparisons are simple, unadjusted contrasts based on posted group summaries. They do not reproduce the sponsor’s ANCOVA model. The unadjusted estimates are reported as active treatment minus placebo; the sponsor’s displayed estimates have the opposite sign for the corresponding comparisons. Differences in adjustment and contrast orientation mean that the estimates should be read according to their own definitions. The sponsor’s reported analysis is the direct account of the sponsor’s method, while the recalculation provides a transparent descriptive comparison from the summary statistics.

How should a p-value be read?

A p-value describes how compatible the observed data are with a specified null model, under the assumptions of the analysis. It is not the probability that the null hypothesis is true, and it does not measure the probability that a result occurred “by chance.” The reported primary p-values are 0.471 and 0.604 for the ANCOVA comparisons. The unadjusted recalculations give 0.468 and 0.598. These values do not indicate a statistically clear difference under commonly used testing conventions, but a p-value alone does not convey the range of effect sizes compatible with the data. Confidence intervals are important for that reason.

The registry record does not report a multiplicity adjustment or a complete testing hierarchy. When several outcomes, arms, or analyses are examined, the chance of at least one apparently notable result can increase if each is tested separately without adjustment. This is a general statistical concern, not evidence that a particular adjustment was or was not performed beyond what is stated in the record.

What does the analysis population mean?

The primary population was not simply every person counted in enrollment. The Modified Intent to Treat definition required a participant to have been randomized, to have taken at least one dose, to have a baseline efficacy evaluation, and to have at least one efficacy evaluation on double-blind treatment. This definition excludes randomized participants who did not meet those measurement and treatment conditions. Such restrictions can affect how representative the analyzed group is of all randomized participants.

The registry does not report how many randomized participants were excluded from this population, why any participants lacked endpoint measurements, or the method used to handle missing data. It also does not report whether other analysis populations were used. These omissions limit assessment of possible bias from missing outcomes or post-randomization exclusions.

Finally, a statistically non-significant result is not proof of no effect, and it is not evidence of equivalence. The estimates and their intervals describe what the observed sample can support. Wider uncertainty leaves a broader range of possible underlying effects unresolved. The record does not state a clinically important difference against which to judge the magnitude of the contrasts.

11. Confidence Intervals and Precision

The sponsor’s 95% confidence interval for the adjusted placebo-versus-DVS SR contrast is -1.42 to 0.66, around an adjusted estimate of -0.38. For placebo versus pregabalin, the adjusted estimate is -0.28 and the 95% confidence interval is -1.33 to 0.77. Each interval includes zero, the value corresponding to no difference under the contrast definition. Each also spans values on both sides of zero, so the direction of the underlying contrast is uncertain.

A confidence interval gives a range of estimates compatible with the data and the statistical model at the stated confidence level. It is not a guarantee that the true effect lies within that particular interval, nor does it assign probabilities to individual values within it. The interval’s width conveys precision: a wider range leaves more possible effect sizes unresolved. The sponsor intervals permit both a contrast favoring one group and a contrast favoring the other, depending on the direction used to define the comparison.

The estimates are not precise enough to identify a narrow range of plausible differences. The absence of a statistically significant result should therefore not be read as proof that the arms have identical effects. Conversely, the intervals do not establish a clinically important benefit in either direction. The registry record does not report a threshold for clinical importance, and statistical compatibility with a range of values is not a judgment about whether those values matter to patients.

Precision is affected by the amount of information available and by outcome variability. This study’s primary analysis included 40 participants in the placebo arm, 42 in the DVS SR arm, and 43 in the pregabalin arm. The study stopped after stage 1. The record does not report the original target sample size or its rationale, so the intended precision cannot be compared with the achieved precision from the registry record alone.

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 planning figures are illustrations based on the observed effect, not the trial’s original design. They assume a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The assumed effect to detect is the stated fraction of the observed effect. These figures are participants per arm, not total participants or total events. The outcome is continuous, so the event-count convention used for time-to-event outcomes does not apply.

The 80% power column gives the number of participants per arm estimated to yield an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column gives the corresponding per-arm planning number for a 90% chance. For example, planning for 100% of the observed DVS SR effect gives 611 participants per arm for 80% power and 818 participants per arm for 90% power. Planning for 75% of the observed effect gives 1,086 and 1,454 participants per arm, respectively; planning for 50% gives 2,443 and 3,270.

The same pattern applies to the pregabalin comparison: the listed per-arm numbers increase as the assumed effect becomes smaller. A smaller difference is harder to distinguish from random variation, so more participants are needed to achieve the same target power, under the stated assumptions. The planning numbers are not observed power and do not show the probability that the trial’s result is correct. They are hypothetical design illustrations based on the observed effect; the original sample-size assumptions are not reported in the registry record.

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, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.380; pooled standard deviation σ = 2.370.
2. n = 2 × (1.96 + 0.842)² × 2.370² / 0.380² = 610.6, rounded up to 611 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
delta <- 0.38                      # observed difference in means
sigma <- 2.36987816142518                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(696787)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 611 (80% power), 818 (90% power)
 75% of observed effect: n per arm = 1,086 (80% power), 1,454 (90% power)
 50% of observed effect: n per arm = 2,443 (80% power), 3,270 (90% power)
power.t.test: 611.5 
Simulated power at n = 611 per arm: 0.803 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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. Analyses Reported by the Sponsor

The sponsor’s own primary analyses are ANCOVA comparisons of adjusted means. They report a placebo-versus-DVS SR estimate of -0.38, with a 95% confidence interval from -1.42 to 0.66 and p = 0.471, and a placebo-versus-pregabalin estimate of -0.28, with a 95% confidence interval from -1.33 to 0.77 and p = 0.604.

The simple recalculations use unadjusted group summaries and express each contrast as active treatment minus placebo. They produce estimates of 0.38 for DVS SR and 0.28 for pregabalin, with p-values of 0.468 and 0.598. The signs differ because the displayed contrasts are oriented in opposite directions; the sponsor results are adjusted, while the recalculations are unadjusted. Their estimates should not be treated as identical model results.

The general inference is similar: neither set of comparisons shows a clear separation from placebo, and the sponsor confidence intervals include zero. The registry does not flag a discrepancy between the reported and recalculated analyses. The sponsor’s ANCOVA results remain the direct reported analysis; the recalculations are descriptive checks based on summary statistics, not replacements for the sponsor’s analysis or its underlying model.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several statistical questions are tested, such as comparisons involving multiple treatment arms, outcomes, time points, or analysis choices. If each test is considered on its own without accounting for the others, the overall chance of a false-positive finding can be higher than the nominal error rate for a single test. This is a general statistical principle.

The registry reports a primary endpoint and one secondary outcome, as well as four analyses overall. It identifies ANCOVA for the sponsor’s reported group comparisons. However, the multiplicity adjustment, if any, and the hierarchy or gatekeeping rules for interpreting the tests are not reported in the registry record. The record also does not say whether the primary comparison was the only confirmatory test or how the pregabalin-referenced comparison and secondary analyses were intended to affect conclusions.

The primary population is defined as Modified Intent to Treat: randomized participants who took at least one dose, had a baseline primary efficacy assessment, and had at least one primary efficacy assessment on double-blind treatment. The registry does not report the number of randomized participants excluded from that population, the reasons for exclusion, or whether the sponsor also performed an analysis of all randomized participants.

Missing-data handling is not reported in the registry record. In particular, the record does not specify how participants without an endpoint score were handled, whether any imputation was used, or whether sensitivity analyses assessed alternative assumptions about missing outcomes. Without those details, it is difficult to judge how robust the estimates are to missing observations.

The trial title describes an adaptive design, and the arm descriptions state that the sponsor stopped the study after stage 1. The adaptation rules, interim analysis plans, stopping criteria, and any adjustments made to statistical testing because of the design are not reported. The reason for termination is also not reported in the registry record. These gaps limit evaluation of the intended analysis strategy and the relationship between the reported results and the original design.

16. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pregnancy and spontaneous abortion (2.3%).

The serious adverse event counts were 0 among 40 participants in the placebo group, 0 among 42 participants in the DVS SR group, and 1 among 43 participants in the pregabalin group. These are counts of participants reported as affected, with the corresponding numbers at risk shown for each arm. The registry also lists “Pregnancy and spontaneous abortion” among the serious adverse event terms, at 2.3%.

These counts describe what the record reports for the study; they do not establish that a study treatment caused an event. Nor do small group counts provide a precise estimate of comparative risk. The registry does not report deaths as a numeric count, so deaths are not reported in the registry record. The broader counts of participants affected by other adverse events are not the same as serious adverse event counts and should not be conflated with them.

The study stopped after stage 1, and the registry does not state the reason for termination. The safety summaries alone do not show whether safety contributed to that decision. They should be interpreted as descriptive counts in a small, terminated study, not as a comprehensive assessment of safety.

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

The posted results show decreases from baseline in mean pain scores in all three arms and no statistically clear difference between either active-treatment arm and placebo in the sponsor’s adjusted analyses. The estimates are accompanied by confidence intervals that include zero and extend in both directions. The data therefore leave uncertainty about the direction and size of any between-group difference.

That pattern does not mean that the groups are proven identical. Failure to distinguish groups statistically is not the same as demonstrating equivalence, and the registry does not report an equivalence or non-inferiority objective. The results also do not establish that the within-group decreases were caused by treatment. Changes from baseline can reflect multiple influences; the randomized between-group contrast is the relevant basis for estimating a treatment difference.

The record does not define a clinically important difference on the Numeric Rating Scale. As a result, the statistical estimates cannot be translated from the registry information alone into a judgment about clinical importance. A confidence interval describes statistical uncertainty under its model, not the value participants would place on a difference.

Interpretation is limited by termination after stage 1, incomplete reporting of missing-data methods and analysis details, and the absence of the original sample-size rationale and adaptive-design rules. The registry does not report why the study was stopped. The findings should be understood as a record of the analyses and participants reported for this trial, rather than a definitive determination about treatment effects or safety.

18. Why This Trial Matters Statistically

This trial illustrates why within-group changes and between-group comparisons answer different questions. Each arm had a negative mean change in pain score, but the treatment question depends on whether the changes differ between randomized groups. The adjusted comparisons, not the direction of the arm means considered separately, are the relevant evidence for those contrasts.

It also demonstrates the importance of reading estimates together with uncertainty. The sponsor’s confidence intervals include zero and span values in both directions. The p-values alone would conceal how much uncertainty remains about the possible contrast. Neither a non-significant test nor a confidence interval containing zero establishes that the treatments are equivalent.

The record is also a useful example of the difference between a reported model-based analysis and a summary-statistic recalculation. ANCOVA adjusts the comparison according to a model whose full details are not available in the registry. A simple unadjusted recalculation can check the broad pattern, but it cannot reproduce all features of the sponsor’s analysis. Contrast direction must also be kept consistent when comparing signs.

Finally, the adaptive-design title and the recorded decision to stop after stage 1 make design transparency especially relevant. Without the decision rules, interim analysis plan, multiplicity strategy, missing-data methods, and reason for stopping, readers cannot fully assess how the observed results relate to the intended trial process. Those reporting limitations are part of the statistical interpretation, not merely administrative details.

19. 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 trial was terminated after stage 1, according to each arm description, but the reason for stopping is not reported in the registry record. The results therefore reflect the first stage only, and the record does not establish whether the stopping decision was related to efficacy, safety, operations, or another consideration. The adaptive design’s planned stages and decision rules are also not reported.

The primary analysis population was restricted to randomized participants who took at least one dose and had both baseline and on-treatment efficacy assessments. The record does not report how many participants were excluded from that population or why. Missing-data methods, the amount and pattern of missing endpoint data, and sensitivity analyses are not reported. These omissions make it difficult to assess the potential influence of missing outcomes and analysis-population selection.

The registry identifies ANCOVA but does not report the covariates or full model specification. It does not state the multiplicity strategy for the primary and secondary outcomes or the treatment comparisons. The original sample-size target, its justification, and the assumptions underlying the planned design are not reported. Planning illustrations based on observed effects cannot fill those gaps.

The study enrolled 125 participants, with modest arm-level analysis sizes. The confidence intervals are broad enough to include differences in both directions, limiting precision. The record also does not provide a threshold for clinical importance on the pain scale. Finally, serious adverse event counts are descriptive and few in number; deaths are not reported in the registry record. These limits constrain both efficacy and safety interpretation.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: A Study Evaluating Desvenlafaxine Sustained Release (DVS SR) in Adult Female Outpatients With Fibromyalgia — NCT00696787.
• Registry record last updated 2013-02-25; status last verified 2013-02.
• Results first posted 2010-02-23.
• 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.

23. Record Summary

The registry describes a randomized, double-blind, phase 2, parallel-group study of DVS SR in adult female outpatients with fibromyalgia. Participants in the first stage were assigned to placebo, DVS SR 200 mg/day, or pregabalin 450 mg/day. The study enrolled 125 participants and was terminated after stage 1.

The primary endpoint was change from baseline in Numeric Rating Scale pain score, with the primary time point at week 8. The sponsor’s adjusted comparisons of DVS SR and pregabalin with placebo had confidence intervals that included zero and p-values of 0.471 and 0.604. Simple unadjusted recalculations show a similar broad pattern, but use different adjustment and contrast conventions.

The registry does not report the reason for termination, the original sample-size rationale, adaptive-design rules, multiplicity strategy, or missing-data methods. These reporting gaps, together with the uncertainty in the estimates, limit the conclusions that can be drawn from the posted results.