Study to Investigate the Analgesic Efficacy of a Single Dose of AZD1940: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Investigate the Analgesic Efficacy of a Single Dose of AZD1940 (NCT00659490), a randomized phase 2 study. The primary outcome is Pain Area Under the Curve 0-8h (AUC0-8h).

2. Clinical Question

3. Trial Design

This was a Phase 2, randomized, double-blind, placebo-controlled, parallel-group study. The masking field reports triple masking. The registry record reports an enrollment of 151 and lists three intervention groups: AZD1940, placebo, and naproxen. The number randomized to each group is reflected in the endpoint results: 61 for AZD1940, 59 for placebo, and 31 for naproxen. Those endpoint counts describe the per-protocol analysis population, rather than establishing how many participants were originally assigned to each arm.

AZD1940 was described as 800ug given predose. Naproxen was 500mg given pre-surgery, while placebo was also given pre-surgery. The clinical setting was surgical removal of an impacted lower wisdom tooth. The stated primary aim was to investigate pain relief after surgery by comparing AZD1940 with placebo; naproxen was included as a comparison. Acetaminophen was allowed as rescue medication if participants needed additional pain relief.

The registry record lists the study as completed and reports a start date of 2008-02 and a primary completion date of 2008-05. It does not report the allocation ratio, the method used to generate the random sequence, concealment procedures, or the specific roles included in triple masking. The protocol's original sample-size justification and planned statistical analysis are not reported in the registry record. The record also does not report whether there were interim analyses or how the analysis population was defined beyond stating that the primary analyses were per-protocol.

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: Screening for eligibility

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analyses based on a per-protocol population.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Pain Area Under the Curve 0-8h (AUC0-8h), measured over 0-8 h(from end of surgery to 8 hours post surgery).

The primary endpoint was the area under the Visual Analogue Scale (VAS) pain curve from the end of surgery to 8 h after surgery, reported in mm*h. The VAS was described as ranging from 0-100 mm. An area-under-the-curve measure combines pain ratings across the interval: it reflects both the reported pain level and how that level changes over time. A larger area indicates more accumulated pain ratings across the measurement period, while a smaller area indicates less.

This kind of endpoint is useful when pain is measured repeatedly, because it summarizes the time course in a single continuous value rather than treating each rating as a separate primary outcome. The measurement window was 0-8 h from the end of surgery. The registry record states that missing values in the pain-by-time curve were imputed using linear interpolation, last observation carried forward (LOCF), or first observation carried backwards (FOCB), as applicable. The primary analyses were based on a per-protocol population.

These choices define what the reported mean represents: an accumulated VAS measure over the stated interval, using the described approach to fill gaps in the curve. Details about how often ratings were scheduled, how the applicable imputation method was selected, and how participants with missing endpoint data were handled beyond these rules are not reported in the registry record.

7. Results Posted in the Registry

• AZD1940: mean 355.00 versus 356.00 on control; difference -1.00 (95% CI -63.29 to 61.29), standardized effect d = -0.01; z-test p = 0.975.
• Naproxen: mean 129.00 versus 356.00 on control; difference -227.00 (95% CI -283.25 to -170.75), standardized effect d = -1.53; 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.

Pain Area Under the VAS Versus Time Curve 0-4h (AUC0-4h)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AZD1940: mean 145.00 versus 143.00 on control; difference 2.00 (95% CI -29.39 to 33.39), standardized effect d = 0.02; z-test p = 0.901.
  • Naproxen: mean 54.00 versus 143.00 on control; difference -89.00 (95% CI -115.18 to -62.82), standardized effect d = -1.25; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AZD1940 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Naproxen than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Maximum Pain Based on VAS Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AZD1940: mean 66.00 versus 65.00 on control; difference 1.00 (95% CI -7.62 to 9.62), standardized effect d = 0.04; z-test p = 0.820.
  • Naproxen: mean 33.00 versus 65.00 on control; difference -32.00 (95% CI -41.47 to -22.53), standardized effect d = -1.41; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AZD1940 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Naproxen than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Mean Pain Based on a VAS Scale

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AZD1940: mean 31.00 versus 29.00 on control; difference 2.00 (95% CI -4.39 to 8.39), standardized effect d = 0.11; z-test p = 0.540.
  • Naproxen: mean 13.00 versus 29.00 on control; difference -16.00 (95% CI -21.66 to -10.34), standardized effect d = -1.07; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AZD1940 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Naproxen than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry record lists a range of secondary pain measures, including pain area over a shorter interval, maximum and mean VAS pain, and pain associated with jaw movement. The posted numerical secondary results show a recurring descriptive pattern: the AZD1940 and placebo group means are close on the reported measures, while the naproxen group means are lower. This overall pattern is broadly consistent with the primary endpoint's near-zero AZD1940-placebo point estimate and the larger naproxen-placebo contrasts.

That consistency should not be treated as several independent confirmations. The secondary measures are related pain outcomes, and several assess overlapping features of pain or different time windows. Correlation among outcomes means that repeated results may contain overlapping information. The secondary results also do not replace the primary comparison, which was defined as pain area over 0-8 h in the per-protocol population.

The registry record lists 21 secondary outcome measures, while the detailed secondary results available for interpretation include the posted summaries for pain area over 0-4h, maximum VAS pain, and mean VAS pain. Additional secondary outcome details are not reported in the registry record. The listed secondary comparisons are unadjusted recalculations from summary statistics; a sponsor-reported set of secondary analyses is not reported in the registry record.

When many outcomes and comparisons are examined, the chance of encountering apparently notable results by chance can increase. A multiplicity adjustment or prespecified hierarchy can help address that issue, but neither is reported in the registry record. Accordingly, secondary p-values should carry less weight than a prespecified primary result and should be interpreted as exploratory context rather than standalone evidence. The registry record also does not report whether all listed secondary outcomes were prespecified in the same form or whether any were selectively emphasized.

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

• Pain Area Under the VAS Versus Time Curve 0-4h (AUC0-4h)
• Maximum Pain Based on VAS Scale
• Mean Pain Based on a VAS Scale
• Pain at Jaw Movement AUC0-8h
• Pain at Jaw Movement AUC0-4h
• Maximum Pain at Jaw Movement
• Mean Pain at Jaw Movement
• Pain at Rescue Medication

9. Statistical Interpretation

10. Statistical Methods Explained

The principal outcome is continuous: each participant contributes a numerical pain-area value, and the registry record reports group means and standard deviations. A mean describes the center of a group’s values. A standard deviation describes how dispersed individual values are around that mean; it is not the uncertainty in the estimated group mean. The standard error, in contrast, describes the estimated sampling uncertainty of a mean or contrast under a statistical model.

What does the mean difference express?

The reported mean differences compare each active group with placebo. For AZD1940, the contrast is AZD1940 minus placebo; for naproxen, it is naproxen minus placebo. A negative value means the active-group mean is numerically lower than the placebo mean for these contrasts. On this pain-area measure, lower values correspond to less accumulated pain rating during the measured interval. These differences are unadjusted calculations from the posted group summaries and are not presented as the sponsor's full analysis.

The standard deviations reported for the primary endpoint were 182.3 for AZD1940, 165.7 for placebo, and 105.4 for naproxen. The group sizes for these endpoint results were 61, 59, and 31, respectively. The differences in group size and variability matter for precision: estimates based on fewer participants or more variable observations tend to be less precise, all else being equal.

What does a confidence interval tell the reader?

A confidence interval gives a range of values reasonably compatible with the observed data under the method used to calculate it. It is not a guarantee that the true effect lies in the interval, and it does not assign probabilities to individual values in the interval. For the primary AZD1940-placebo contrast, the interval extends on both sides of zero, so the posted summary is compatible with a range of possible differences rather than a precise estimate of no difference.

The primary comparison's p-value is unadjusted. In general, a p-value assesses how unusual data at least as discrepant as those observed would be if the null hypothesis and the statistical model were correct. It does not indicate the probability that the null hypothesis is true, nor does it measure the magnitude or importance of an effect. Interpretation should therefore consider the estimate and its confidence interval, not the p-value alone.

Why can variation matter?

General statistical explanation: when individual observations vary considerably within groups, a given group mean difference is harder to estimate precisely. In clinical outcomes, variation may reflect real differences among participants, measurement variability, or other factors. Over-dispersion is a related issue in outcomes where observed variability exceeds what a chosen model expects; accounting for it can affect standard errors and intervals. The registry record does not identify over-dispersion as a problem or report a model-based adjustment for it, and the primary endpoint is analyzed as a continuous measure.

The recorded primary endpoint was constructed from repeated VAS measurements. Missing curve values were imputed using linear interpolation, LOCF, or FOCB as applicable. General explanation: interpolation estimates a value between measured time points; carrying the last observation forward or first observation backward uses a neighboring recorded value to fill a missing point. These methods can make the summary curve calculable, but their suitability depends on the pattern and reasons for missingness. The missingness pattern and method-selection details are not reported in the registry record.

What does the per-protocol population imply?

The registry record states that the primary analyses used a per-protocol population. This means the stated analysis population was not described simply as everyone enrolled. The rules for entering or remaining in that population, and the number excluded from it, are not reported in the registry record. An intention-to-treat analysis is also not reported. Results for a per-protocol population should be understood as applying to the participants included under that analysis definition, not automatically to all randomized participants.

Finally, the planning figures are illustrations based on the observed effects and specified assumptions, rather than a description of the trial's original design calculations. The original sample-size rationale and statistical analysis plan are not reported in the registry record. That distinction matters because a calculation made after viewing observed summary effects answers a different question from a prospective design calculation based on a prespecified target difference.

11. Confidence Intervals and Precision

Precision is best judged from the confidence interval as well as the point estimate. For AZD1940 versus placebo on the primary 0-8 h pain-area endpoint, the estimated mean difference was -1.0 mm*h and the 95% confidence interval was -63.29 to 61.29. The interval includes zero and extends in both directions, indicating that the estimate is not precise enough to rule out a range of differences. The near-zero point estimate alone should not be read as proof that the groups had identical underlying means.

The interval's width reflects sampling uncertainty under the method used to calculate it. General explanation: uncertainty tends to be greater when the sample is small, measurements are variable, or the analysis has limited information. In this trial, the endpoint groups contained 61 AZD1940 participants and 59 placebo participants, and the reported standard deviations were 182.3 and 165.7. These descriptive details help contextualize why a small observed difference does not necessarily imply a tightly estimated effect.

The naproxen-placebo primary contrast was -227.0 mm*h, with an interval from -283.3 to -170.7. That interval is entirely below zero, but it remains an unadjusted recalculation from posted summary statistics rather than the complete sponsor analysis. Confidence intervals for the secondary contrasts also vary in width and should be considered alongside the multiplicity concerns described for the trial's many outcomes.

The registry record does not report a threshold for a clinically important difference. Consequently, the confidence interval cannot be judged against such a threshold using the registry information alone. Precision is about how tightly an effect is estimated; clinical importance is a separate question that requires an appropriate interpretive threshold and context.

12. Planning a Similar Trial: Sample Size

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

The sample-size figures are planning illustrations based on the observed effect, not the trial's original design justification. The registry record's own assumptions for its original sample-size calculation are not reported. For the illustrations, the assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set to the stated fraction of the observed effect. The figures are participants per arm, not total participants or total events, because these outcomes are continuous rather than time-to-event outcomes.

The 80% power column gives the illustrative number of participants per arm needed for an analysis to have an 80% chance of detecting the chosen effect under those assumptions, if that effect is the true one. The 90% column uses a higher chance of detection and therefore generally requires more participants. For example, planning for 100% of the observed AZD1940-placebo primary effect gives 477,116 participants per arm for 80% power and 638,722 participants per arm for 90% power. For the naproxen-placebo primary contrast, the corresponding figures are 7 and 9.

The rows that plan for 75% or 50% of the observed effect represent smaller target differences. Smaller effects are harder to distinguish from random variation, so they require more participants under the same assumptions. The extremely large AZD1940 planning figures reflect the very small observed AZD1940-placebo difference used as the target; they should not be interpreted as a recommendation for a future study.

The curve is a visual aid for understanding how the planning requirement changes with the target effect. These calculations describe prospective planning under stated assumptions. They are not observed power, and they do not tell whether the completed trial had an adequate sample size under its original design rationale.

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 = -1.000; pooled standard deviation σ = 174.338.
2. n = 2 × (1.96 + 0.842)² × 174.338² / -1.000² = 477,115.3, rounded up to 477,116 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 <- -1                      # observed difference in means
sigma <- 174.338308848639                     # 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(659490)
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 = 477,116 (80% power), 638,722 (90% power)
 75% of observed effect: n per arm = 848,205 (80% power), 1,135,506 (90% power)
 50% of observed effect: n per arm = 1,908,462 (80% power), 2,554,888 (90% power)
power.t.test: 477116.2 
Simulated power at n = 477,116 per arm: 0.801 (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 study includes a primary endpoint and many secondary pain outcomes. The registry record lists 22 outcome measures in total and identifies 21 as secondary. Multiple measures, time windows, and group contrasts create a multiplicity issue: the more statistical comparisons considered, the greater the opportunity for some results to appear notable by chance, even if there is no underlying effect for those comparisons.

The posted p-values for the recalculated comparisons are unadjusted. A family-wise adjustment, false-discovery approach, or prespecified testing hierarchy is not reported in the registry record. Nor is a complete statistical analysis plan reported. Without those details, the secondary results should not be interpreted as if each were an independently confirmed hypothesis test. The primary endpoint provides the clearest stated focus, while the secondary results offer descriptive context.

Missing-data handling for the primary pain curve is partly described: missing values were imputed using linear interpolation, LOCF, or FOCB as applicable. The record does not report how much data were missing, why values were missing, how the applicable method was selected, or whether sensitivity analyses assessed alternative assumptions. These details matter because imputation can affect the endpoint when missing observations differ systematically from the observed ones.

The primary analyses were based on a per-protocol population. The criteria used to define that population, exclusions from it, and the number of participants excluded are not reported in the registry record. An intention-to-treat analysis is not reported. The consequences of these omissions cannot be determined from the posted summaries alone. In particular, the available information does not establish how the results would differ under another analysis population or missing-data approach.

Interim analyses and stopping rules are not reported in the registry record. The sponsor's full statistical analyses, including any adjusted model, covariates, or multiplicity procedures, are also not reported. These gaps limit reconstruction of the full inferential strategy and call for a cautious reading of the summary comparisons.

15. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry record reports no serious adverse events among the 61 participants at risk in the AZD1940 group, the 59 at risk in the placebo group, or the 31 at risk in the naproxen group. These are counts for the reported groups during the period captured by the registry record. They do not establish that no serious events could occur outside the observed participants or the recorded follow-up.

For other adverse events, the record reports 3 affected participants in the AZD1940 group, 2 in the placebo group, and 0 in the naproxen group. These counts are separate from the serious adverse event figures. The record does not provide further detail about the specific non-serious events in the information summarized for this analysis. Death counts are not reported in the registry record.

Adverse-event counts should be read with the group sizes and the study's short postoperative context in mind. The registry record does not report enough detail to assess event severity beyond the serious/non-serious distinction, timing, relatedness, or comparative risk with precision. These figures are a description of recorded events, not a comprehensive assessment of safety.

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

The posted primary results describe a mean 0-8 h pain-area value of 355.0 mm*h with AZD1940 and 356.0 mm*h with placebo. The corresponding mean difference is -1.0 mm*h, with a 95% confidence interval from -63.29 to 61.29 and an unadjusted p-value of 0.975. The point estimate is close to zero, but the interval is broad and compatible with differences in either direction. The results therefore do not give a precise estimate of the AZD1940-placebo contrast.

The naproxen group had a lower mean pain-area value than placebo in the posted summary, and the unadjusted recalculated contrast is -227.0 mm*h. This is a comparison in the registry results, not a basis for making a treatment recommendation or a claim beyond this trial's design and recorded outcome. The sponsor's complete analysis and any adjustment procedures are not reported in the registry record.

These results concern a specific outcome, a defined postoperative interval, and the per-protocol analysis population. They do not establish what would happen in other procedures, populations, dosing regimens, follow-up periods, or clinical settings. The registry record does not report a clinically important difference threshold for the pain-area measure, so the clinical meaning of a given numerical difference cannot be determined from statistical significance alone.

Likewise, a non-significant p-value is not proof of equivalence or proof that two groups are identical. Equivalence would require a prespecified margin and an analysis designed to evaluate that question; such a margin is not reported in the registry record. The confidence interval, rather than the p-value alone, communicates the range of differences still compatible with the observed data under the calculation used.

The results are best understood as a record of observed group summaries and uncertain contrasts. They support neither a definitive conclusion that AZD1940 changed the primary outcome nor a definitive conclusion of no possible difference. More complete protocol and analysis information would be needed to assess the design rationale, missing-data sensitivity, and the full inferential approach.

17. Why This Trial Matters Statistically

This trial illustrates why the numerical estimate and its precision should be read together. The primary AZD1940-placebo mean difference is close to zero, but its confidence interval extends across a substantial range on either side. Looking only at the point estimate might suggest certainty where the data do not provide it; looking only at a p-value would also hide the range of plausible differences represented by the interval.

The inclusion of naproxen as a comparison group gives the study a second descriptive contrast, but that contrast does not change which comparison was identified as primary. Separating the main question from additional comparisons is important in trials with several outcomes, particularly when the secondary p-values are unadjusted and a multiplicity plan is not reported.

The record also highlights the importance of analysis population and endpoint construction. The primary analysis was per-protocol, and the pain-area endpoint used imputation for missing curve values. Those choices are part of what the reported mean difference means. Without the population rules, missingness details, and full analysis plan, readers cannot fully evaluate how alternative analytic choices might affect the result.

Finally, planning illustrations based on an observed effect are not a substitute for a prospective design rationale. The registry record does not report its original sample-size assumptions. Keeping the post hoc planning figures distinct from the trial's design helps prevent an illustrative calculation from being mistaken for evidence about the study's original planning or its observed power.

18. Limitations

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

The registry record provides arm-level means and standard deviations for the primary endpoint, but does not report the complete sponsor analysis output or an adjusted treatment estimate. The recalculated contrasts are unadjusted comparisons from summary statistics. Their intervals and p-values should not be mistaken for the trial's full prespecified analysis unless that is confirmed elsewhere; the full analysis plan is not reported in the registry record.

The primary endpoint analysis was per-protocol. The criteria for inclusion in that population and the number excluded from it are not reported in the registry record. As a result, the endpoint counts cannot be used to reconstruct all aspects of participant flow or to compare the per-protocol findings with an intention-to-treat analysis.

The outcome depends on a pain curve with missing values imputed by linear interpolation, LOCF, or FOCB as applicable. The amount and pattern of missingness, the circumstances prompting each approach, and sensitivity analyses are not reported. These omissions restrict assessment of how dependent the endpoint estimate may be on the imputation choices.

The record lists many secondary measures, but not a multiplicity adjustment or testing hierarchy. This limits the strength of inferences from unadjusted secondary comparisons. The registry record also does not report the original sample-size assumptions, allocation ratio, randomization implementation, or interim-analysis plan. These limitations are specific to what can be assessed from the posted registry information and do not establish that procedures were absent from the underlying trial.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Study to Investigate the Analgesic Efficacy of a Single Dose of AZD1940 — NCT00659490.
• Registry record last updated 2012-06-11; status last verified 2010-05.
• Results first posted 2012-03-26.
• 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

NCT00659490 is a completed Phase 2 randomized, triple-masked, parallel-group study of single-dose AZD1940 for pain after impacted mandibular third molar extraction. The trial included AZD1940, placebo, and naproxen groups, with acetaminophen permitted as rescue medication.

The primary endpoint was pain area under the VAS curve from the end of surgery to 8 h, analyzed in a per-protocol population. The AZD1940-placebo mean difference was -1.0 mm*h, with a 95% confidence interval from -63.29 to 61.29 and an unadjusted p-value of 0.975. The posted results do not precisely determine the size or direction of that contrast.

The registry record reports no serious adverse events in the three groups. Details of the original sample-size rationale, full analysis plan, multiplicity handling, and additional missing-data sensitivity analyses are not reported in the registry record.