An Abuse Potential Study of Orally Administered HORIZANT in Healthy, Non-dependent, Recreational Drug Users: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for An Abuse Potential Study of Orally Administered HORIZANT in Healthy, Non-dependent, Recreational Drug Users (NCT06097676), a randomized phase 4 study. The primary outcome is Drug Liking "at This Moment" Visual Analog Scale (VAS).

2. Clinical Question

3. Trial Design

The registry describes a Phase 4, randomized, quadruple-masked, active- and placebo-controlled crossover study. Its official title calls it a five-way crossover study, and the listed conditions were placebo, alprazolam 2 mg, and GE-IR at 200 mg, 450 mg, and 700 mg. Each condition is described as a single oral dose. In a crossover design, treatment conditions are evaluated across treatment periods rather than assigning each participant to only one condition. The record does not report the treatment sequence, period structure, washout arrangements, or how possible period or carryover effects were handled.

The stated purpose was to assess the abuse potential of gabapentin enacarbil in healthy adult, non-dependent recreational drug users. The study started on 2021-09-28, reached primary completion on 2022-06-30, and is marked completed. Registry enrollment was 86. The primary outcome results list 47 participants in each condition, but the record does not explain the analysis population, participant flow, or why the outcome count differs from overall enrollment. Those counts should not be treated as evidence that every enrolled participant completed every treatment period.

Randomization and masking are design features intended to reduce systematic differences in treatment assignment and assessment. The registry labels masking as quadruple but does not identify which roles were masked or describe how masking was maintained. It also does not report the trial’s original sample-size justification or detailed statistical analysis plan. The posted record includes outcome summaries and comparisons, but no reported analyses are listed.

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.

Only the first 6 of 10 groups are shown.

Overall Study

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: Subjects in the treatment phase (randomized population)

6. Primary Endpoint

The registry lists the primary outcome as Drug Liking "at This Moment" Visual Analog Scale (VAS), measured over approximately 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 10, and 24 hours postdose in the treatment phase and per period of the treatment phase.

The primary endpoint is the mean difference in Drug Liking Emax over 24 hours. Participants rated the statement “At this moment, my liking for this drug is” on a bipolar visual analog scale. The scale runs from 0, strong disliking, through 50, neither like nor dislike, to 100, strong liking. Emax refers to the maximum response during the defined assessment period; the endpoint therefore concerns the peak reported liking rather than an average of all moment-by-moment ratings. Measurements were scheduled at approximately 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 10, and 24 hours postdose in the treatment phase and per period of the treatment phase.

This type of subjective rating is used in abuse-potential studies to quantify participants’ immediate drug-liking response under the study conditions. A score closer to the strong-liking end indicates a greater reported liking response on this scale; it does not by itself establish whether a person would use a drug outside the study or develop dependence. The endpoint is also not a clinical benefit measure. Its interpretation is limited to the selected participants, the study setting, and the reported treatment conditions.

The registry reports group means and standard errors for the endpoint. It does not provide the individual response distributions or the sponsor’s detailed model for estimating Emax, so the summaries do not show how much participants’ responses varied beyond the reported uncertainty around the means.

7. Results Posted in the Registry

• Alprazolam 2 mg: mean 83.80 versus 54.10 on control; difference 29.70 (95% CI 24.94 to 34.46), standardized effect d = 2.53; z-test p = <0.001.
• GE-IR 200 mg: mean 58.90 versus 54.10 on control; difference 4.80 (95% CI 0.04 to 9.56), standardized effect d = 0.41; z-test p = 0.048.
• GE-IR 450 mg: mean 58.40 versus 54.10 on control; difference 4.30 (95% CI 0.18 to 8.42), standardized effect d = 0.42; z-test p = 0.041.
• GE-IR 700 mg: mean 68.50 versus 54.10 on control; difference 14.40 (95% CI 8.51 to 20.29), standardized effect d = 0.99; z-test p = <0.001.

8. Secondary Efficacy Endpoints

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

Overall Drug Liking VAS

• 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:
  • Alprazolam 2 mg: mean 86.60 versus 54.20 on control; difference 32.40 (95% CI 27.06 to 37.74), standardized effect d = 2.45; z-test p = <0.001.
  • GE-IR 200 mg: mean 62.80 versus 54.20 on control; difference 8.60 (95% CI 2.57 to 14.63), standardized effect d = 0.58; z-test p = 0.005.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Alprazolam 2 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for GE-IR 200 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Take Drug Again VAS

• 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:
  • Alprazolam 2 mg: mean 87.40 versus 55.20 on control; difference 32.20 (95% CI 25.68 to 38.72), standardized effect d = 2.00; z-test p = <0.001.
  • GE-IR 200 mg: mean 64.60 versus 55.20 on control; difference 9.40 (95% CI 1.95 to 16.85), standardized effect d = 0.51; z-test p = 0.013.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Alprazolam 2 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for GE-IR 200 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

High VAS

• 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:
  • Alprazolam 2 mg: mean 65.50 versus 5.20 on control; difference 60.30 (95% CI 50.86 to 69.74), standardized effect d = 2.58; z-test p = <0.001.
  • GE-IR 200 mg: mean 11.70 versus 5.20 on control; difference 6.50 (95% CI -0.99 to 13.99), standardized effect d = 0.35; z-test p = 0.089.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Alprazolam 2 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between GE-IR 200 mg and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover overall drug liking, willingness to take the drug again, and feeling high. Their posted group means show a broadly similar ordering to the primary outcome: alprazolam has the highest reported means, and GE-IR 700 mg is generally above the lower GE-IR doses and placebo. These measures capture related but distinct subjective responses. They provide context for the primary drug-liking endpoint, but they do not measure the same response or establish a single overall abuse-potential result.

The record includes unadjusted comparisons for some secondary contrasts, while other listed conditions have group summaries without a corresponding comparison in the posted secondary results. Those descriptive means should not be mistaken for formal evidence of a difference. Across the endpoints, the direction and magnitude of scores are useful for understanding the observed pattern, but the registry does not report sponsor analyses for these secondary outcomes.

Unadjusted secondary results carry less weight because several outcomes and comparisons are examined, and the record does not report a multiplicity strategy. General explanation: when many hypotheses are tested, the chance of observing an apparently notable result by chance can increase unless the analysis plan accounts for the number of tests. The secondary p-values therefore should be interpreted as exploratory signals rather than stand-alone confirmatory findings. Their relationship to the primary result is descriptive: they appear to measure connected aspects of subjective response, but no combined endpoint or confirmatory hierarchy is reported in the registry record.

The record does not report whether secondary analyses were prespecified, how missing secondary ratings were handled, or which population was used for each outcome. These omissions make it difficult to judge whether differences in the secondary pattern reflect the measured responses, analysis choices, or incomplete data. The secondary outcomes can complement the primary endpoint, but they cannot replace a documented, multiplicity-aware analysis.

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

• Overall Drug Liking VAS
• Take Drug Again VAS
• High VAS

9. Statistical Interpretation

10. Statistical Methods Explained

The posted outcome is continuous: it is a score on a visual analog scale. The record reports a mean and standard error for each treatment condition. A mean describes the average score in the analyzed group; a standard error describes the precision of that estimated mean, rather than the spread of individual participants’ scores. General statistical explanation: the standard error tends to be smaller when a group mean is estimated more precisely, while individual scores can still vary substantially around that mean.

What does the mean difference represent?

The primary comparisons are expressed as mean differences from placebo. The positive estimates indicate that the reported GE-IR group means were higher than the placebo mean on this scale. For example, the posted difference for GE-IR 700 mg is 14.4 points. This is a contrast between group means, not the score of a typical individual and not a percentage change. The registry reports the treatment means, the placebo mean, and the recalculated contrasts with confidence intervals.

The comparison figures are simple, unadjusted recalculations from the posted summary statistics. They are not identified as sponsor analyses, and the registry reports no analyses in its analysis listing. The registry record does not describe whether the sponsor used a model that accounted for the crossover structure, nor does it provide an original analysis plan. For a crossover study, treatment responses from the same participant may be related; a model that accounts for that relationship can differ from a calculation that treats groups as independent. The posted recalculations should therefore be read as descriptive, unadjusted comparisons, not a substitute for a documented sponsor analysis.

What do the confidence intervals and p-values say?

A confidence interval gives a range of values compatible with the estimate under the assumptions used for its calculation. General explanation: a narrower interval conveys greater precision than a wider interval, while neither guarantees that the true effect lies within the reported range. The primary comparisons include intervals for the difference from placebo. The record also gives unadjusted p-values. A p-value describes how compatible the observed data are with a specified no-difference model under the calculation’s assumptions; it is not the probability that the treatment has no effect. These p-values do not account for multiplicity.

The registry lists p < 0.001 for alprazolam 2 mg and GE-IR 700 mg, p = 0.048 for GE-IR 200 mg, and p = 0.041 for GE-IR 450 mg. The p-values for the two lower GE-IR doses are close to the conventional 0.05 threshold, but a threshold-based reading does not resolve the multiple-comparison issue or the limitations of unadjusted calculations. The confidence intervals and estimates are more informative when read together than a binary distinction between a result that crosses a threshold and one that does not.

Why does the crossover design matter?

General explanation: crossover designs can use within-participant information because participants receive more than one condition, which may reduce the influence of stable differences between people. Their interpretation also depends on features such as treatment sequence, period effects, and carryover. The registry identifies the design as crossover but does not report the sequence, washout, model terms, or handling of these features. It is therefore not possible from the registry record to determine how these design considerations were incorporated into the posted results.

The primary endpoint is a maximum score over a defined postdose period. Measurements were scheduled repeatedly, but the endpoint is not the mean of all scheduled scores. The record does not report the exact procedure used to derive each participant’s Emax when measurements were missing or how incomplete measurement schedules were handled. This matters because a maximum can depend on the amount and timing of observed data. No assumptions about the derivation or missing-data procedure should be inferred from the summary alone.

What can be inferred from the reported analysis information?

The record supplies group summaries and recalculated unadjusted comparisons, but it lists no reported analyses. The original statistical analysis plan, model specification, handling of missing observations, analysis populations, and multiplicity adjustment are not reported in the registry record. General explanation: model and analysis choices can affect estimated uncertainty, particularly when the design includes repeated treatment periods or several comparisons. The reported summaries remain useful for describing the observed pattern, but they cannot establish that the recalculations reproduce the trial’s intended inferential analysis.

There is no discrepancy flag for these recalculations. That does not turn them into sponsor-reported results; it means the record does not identify a discrepancy between the recalculated values and another sponsor analysis. Since no sponsor analysis is listed, interpretation should retain the distinction between the posted arm summaries and the unadjusted recalculated contrasts.

11. Confidence Intervals and Precision

The primary confidence intervals show the estimated precision of the unadjusted mean differences from placebo. For GE-IR 200 mg, the estimate is 4.8, with an interval from 0.045 to 9.555. For GE-IR 450 mg, the estimate is 4.3, with an interval from 0.184 to 8.416. For GE-IR 700 mg, the estimate is 14.4, with an interval from 8.512 to 20.29. The alprazolam 2 mg estimate is 29.7, with an interval from 24.94 to 34.46. Each interval describes uncertainty around a mean difference, not the range of individual participant responses.

General explanation: a confidence interval combines the estimated effect with its uncertainty under the calculation’s assumptions. A wider range indicates less precise estimation than a narrower range. Precision should be considered alongside the size and context of the estimate; an interval alone does not say whether an effect is important. The registry does not report a threshold for an important difference on the drug-liking scale.

These intervals accompany simple unadjusted recalculations from posted summary statistics, rather than reported sponsor analyses. The registry does not report whether its intended analysis incorporated within-participant correlation, treatment period, or other crossover features. The posted intervals therefore do not document the precision from the trial’s original statistical model. In addition, the record does not report a multiplicity adjustment, and the stated intervals should not be read as resolving uncertainty from examining several treatment comparisons.

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 participants per arm for 80% power and participants per arm for 90% power. They are not total event counts. The registry’s 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 fraction of the observed effect. For example, the displayed rows for 75% of the observed effect use a smaller target effect than the rows for 100% of the observed effect. The registry’s own original design assumptions and sample-size justification are not reported in the registry record.

In plain terms, the 80% power column gives the estimated number of participants per arm under those planning assumptions for a design with an 80% chance of detecting the specified effect if that effect were present. The 90% column uses a higher probability of detection under the same stated framework. These are planning illustrations, not a report of the study’s achieved probability of detecting an effect. They are not observed power.

Smaller target effects require more participants under the stated assumptions. Thus the planning figures increase when the target is reduced from the observed effect to a fraction of it. The estimates are tied to the observed effect and the assumptions listed, and they should not be treated as the enrollment target for this crossover trial. The record does not report that the trial was designed using these illustrations or that its original design used equal allocation between independent arms.

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 = 29.700; pooled standard deviation σ = 11.761.
2. n = 2 × (1.96 + 0.842)² × 11.761² / 29.700² = 2.5, rounded up to 3 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 <- 29.7                      # observed difference in means
sigma <- 11.7607950411526                     # 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(6097676)
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 = 3 (80% power), 4 (90% power)
 75% of observed effect: n per arm = 5 (80% power), 6 (90% power)
 50% of observed effect: n per arm = 10 (80% power), 14 (90% power)
power.t.test: 3.7 
Simulated power at n = 3 per arm: 0.640 (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. Multiplicity, Missing Data and Analysis Populations

The record lists one primary outcome and three secondary outcomes, with several treatment conditions and comparator contrasts. The posted p-values are explicitly unadjusted. The registry record does not report a multiplicity procedure, such as a prespecified testing hierarchy or an adjustment across outcomes and comparisons. Without that information, the family of tests and the intended confirmatory comparisons are unclear. General explanation: multiplicity matters because considering multiple results can increase the chance of at least one apparently unusual finding under a no-effect scenario.

The trial is described as a randomized crossover study, but the registry record does not report the statistical model, the analysis population, or whether the reported calculations account for repeated observations within participants. It also does not report treatment sequence, period effects, carryover assessment, or a method for handling missing observations. Those details are relevant to how uncertainty and treatment contrasts should be estimated in a crossover design. No particular model or data-handling approach can be inferred from the registry description alone.

Outcome counts are listed as 47 for each primary treatment condition, while total enrollment is 86. The record does not provide participant flow or explain this difference. It also does not state whether the same participants contributed data to each condition or identify an intention-to-treat, per-protocol, or other analysis population. The crossover label makes repeated participation across conditions part of the stated design, but the available record does not specify how complete or incomplete treatment periods were handled.

The registry lists no reported analyses. As a result, the primary and secondary comparisons available for interpretation are the posted summaries and unadjusted recalculations, not a documented sponsor analysis. The original analysis plan, missing-data strategy, multiplicity handling, and analysis populations are not reported in the registry record. These gaps limit assessment of whether the posted estimates answer the trial’s planned statistical questions and how robust the inferential conclusions would be under alternative analysis choices.

15. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The serious adverse event figures show zero affected participants in each listed condition: placebo, alprazolam 2 mg, and GE-IR at 200 mg, 450 mg, and 700 mg. The listed numbers at risk range from 49 to 51 across those conditions. The record also lists zero deaths in every condition. No serious adverse event terms are listed.

Other adverse events were reported for 2 participants in the placebo condition, 40 in the alprazolam 2 mg condition, 6 in the GE-IR 200 mg condition, 5 in the GE-IR 450 mg condition, and 17 in the GE-IR 700 mg condition. These are counts of participants affected in the registry’s safety summary, not a measure of severity or a comparison adjusted for the study design. The record does not provide event-level detail or explain how participants contributing to multiple treatment periods are represented in these figures.

Zero reported serious events does not establish that serious events cannot occur, and these counts alone do not support a causal safety comparison. The trial’s selected population and the reported study conditions constrain what can be learned from the safety summary. Further details about adverse-event definitions and collection are not reported in the registry record.

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

The posted results describe subjective drug-liking ratings after single oral doses in healthy, non-dependent recreational drug users with sedative experience. The GE-IR group means were higher than the placebo mean for the primary outcome, with the largest reported GE-IR mean at 700 mg. Alprazolam 2 mg had a higher mean than the GE-IR conditions. These summaries describe responses recorded during the study’s assessment period; they are not evidence about behavior outside the study.

The primary endpoint is a self-reported score on a bipolar scale. It provides information about immediate liking in the participants and conditions studied, not direct evidence of misuse, repeated use, dependence, or long-term consequences. The registry record does not report a threshold that would translate a difference in points into a meaningful change in real-world risk. Nor does it report results for populations other than the selected recreational drug users described in the eligibility context.

The unadjusted recalculated comparisons and confidence intervals help describe differences and their precision, but no sponsor analyses are listed. The registry record also does not report the crossover model, analysis populations, missing-data approach, or multiplicity strategy. Those limitations make the recalculated p-values insufficient as a complete basis for confirmatory interpretation. The secondary endpoints are related subjective measures, but their unadjusted comparisons also need cautious interpretation.

The safety summary lists no serious adverse events or deaths in the displayed conditions, while other adverse events are reported in each condition. Such counts are descriptive and do not establish comparative safety. Overall, the registry supports a description of the observed ratings and adverse-event counts in this study; it does not warrant medical advice or conclusions about treatment for an individual, nor does it establish outcomes beyond the trial setting.

17. Why This Trial Matters Statistically

This trial illustrates how a continuous subjective endpoint can be used to compare several treatment conditions with placebo. The scale has an interpretable midpoint and endpoints, and the registry reports means, standard errors, differences, confidence intervals, and unadjusted p-values. Reading these together is more informative than focusing on a single significance threshold: the estimates convey direction and size, while intervals convey precision under the calculation’s assumptions.

The crossover design is statistically important because the same participant may contribute responses under multiple conditions. This can make within-participant comparisons informative, but correct inference depends on an analysis that reflects the repeated-treatment structure. The registry identifies the design but does not report the model or key design details needed to evaluate how that structure was handled. This contrast between a clearly stated design label and absent analysis details is a useful reminder to distinguish descriptive summaries from documented inferential results.

The record also illustrates the role of active and placebo comparators. The posted alprazolam results provide a reference point for interpreting the scale’s observed range, while placebo serves as the reference for the listed mean differences. The registry does not state formal validation criteria, so the active comparator’s role should not be extended beyond the comparisons that are reported.

Finally, multiple outcomes and treatment contrasts make multiplicity relevant. Unadjusted results can help describe patterns, but without a reported analysis plan and multiplicity approach, the strength of confirmatory claims is difficult to assess. Transparent reporting of the model, analysis populations, missing-data methods, and planned testing strategy would help readers determine how the posted estimates relate to the trial’s intended questions.

18. Limitations

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

Several limitations are specific to the available record. Although the study is labeled crossover, the registry does not report treatment sequence, period structure, washout arrangements, or how carryover and period effects were handled. It also does not give the model used for the primary analysis. These omissions matter because a crossover design involves repeated treatment conditions, and unadjusted contrasts may not reflect the analysis intended for that structure.

The overall enrollment is 86, whereas the primary outcome summaries list 47 participants per condition. Participant flow, the analysis population, and the reason for the outcome counts are not reported in the registry record. It is also unclear how incomplete treatment periods or missing ratings were handled. Because the primary endpoint is an Emax over a series of postdose assessments, the record’s lack of detail on deriving the maximum from incomplete observations is a further limitation.

The comparisons and p-values are unadjusted recalculations from posted summary statistics, and no sponsor-reported analyses are listed. The record does not report the original sample-size justification, statistical plan, or multiplicity procedure. The listed planning figures are illustrations based on observed effects and stated assumptions, not evidence about the study’s original design. Secondary comparisons are incomplete across listed conditions, and no adjustment strategy is reported.

The study population is restricted to healthy, non-dependent recreational drug users with sedative experience. The record does not establish how these results apply to other populations or settings. Safety figures are summary counts without event-level detail, and the registry does not explain how repeated treatment periods affect their interpretation. These limitations constrain both statistical and broader interpretation.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: An Abuse Potential Study of Orally Administered HORIZANT in Healthy, Non-dependent, Recreational Drug Users — NCT06097676.
• Registry record last updated 2024-08-12; status last verified 2024-08.
• Results first posted 2024-01-03.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

The completed Phase 4 study was randomized, quadruple-masked, and crossover, with placebo, alprazolam 2 mg, and GE-IR 200 mg, 450 mg, and 700 mg conditions. It enrolled 86 participants and focused on healthy, non-dependent recreational drug users with sedative experience. The primary outcome was mean Drug Liking Emax over 24 hours, measured on a bipolar visual analog scale.

Posted primary outcome means were 54.1 for placebo, 83.8 for alprazolam 2 mg, and 58.9, 58.4, and 68.5 for the three GE-IR doses. The recalculated unadjusted comparisons show positive mean differences from placebo, with confidence intervals and p-values reported for each contrast. No sponsor analyses are listed. The record does not report the original statistical plan, analysis populations, missing-data methods, or multiplicity approach, so the results are best read as descriptive posted summaries and unadjusted comparisons.