Efficacy and Safety of Adalimumab in Adult Chinese Subjects With Active Ankylosing Spondylitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of Adalimumab in Adult Chinese Subjects With Active Ankylosing Spondylitis (NCT01114880), a randomized phase 3 study. The primary outcome is Number of Participants Meeting the Assessment of Spondyloarthritis International Society (ASAS) ASAS20 Response Criteria.

2. Clinical Question

The primary outcome is a count of participants meeting a multidomain response definition, rather than a change in one symptom alone. The registry record reports 154 responders among 229 participants assigned to adalimumab and 35 among 115 assigned to placebo. The posted comparison is an unadjusted risk difference, and the registry record also reports a chi-squared analysis with p < 0.001.

The clinical question is specifically about the blinded comparison through Week 12. Since both groups were assigned open-label adalimumab from Week 12 to Week 24, later outcomes address a different treatment context and are not a continued placebo-controlled comparison.

3. Trial Design

This was a Phase 3, randomized, triple-masked, parallel-group, placebo-controlled, multicenter study. The registry record describes the study as completed, with enrollment of 344 participants. The study concerned adult Chinese participants with active ankylosing spondylitis who had an inadequate response to or were intolerant to one or more nonsteroidal anti-inflammatory drugs.

During the blinded period, one group received adalimumab and the other received placebo from Week 0 to Week 10. Both groups then had open-label adalimumab from Week 12 to Week 24. The primary endpoint was assessed at Week 12, when the comparison reflects the assigned blinded treatments. The group names in the posted results retain both phases of the treatment sequence: Adalimumab/Adalimumab and Placebo/Adalimumab.

The primary analysis population was the intent-to-treat analysis set as defined in the registry record: randomized participants who received at least one dose of double-blind study drug. Missing primary responses were imputed as non-response. The record reports 229 participants in the Adalimumab/Adalimumab group and 115 in the Placebo/Adalimumab group for the primary outcome.

The registry record does not report the randomization procedure, masking details beyond the designation triple masked, or the original sample-size justification. It also does not report the study's full statistical analysis plan. The posted record names the primary and secondary outcomes and includes an analysis method for the primary comparison, but those details do not establish all planned analytical choices.

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.

Period 1 (Week 0 to Week 12)

Reasons for not completing this period:

Period 2 (Week 12 to Week 24)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was performed on the Intent-to-Treat (ITT) analysis set, which included all subjects who were randomized and received at least 1 dose of double-blind study drug. A non-responder (NRI) imputation was used in which a missing response was imputed as non-response.

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Meeting the Assessment of Spondyloarthritis International Society (ASAS) ASAS20 Response Criteria, measured over Week 12.

The primary endpoint counts participants meeting the Assessment of Spondyloarthritis International Society ASAS20 response criteria at Week 12. A responder had to show improvement of at least 20% and an absolute improvement of at least 10 units from baseline in at least three of four domains: the participant's global assessment of disease activity, total back pain, physical function measured by BASFI, and inflammation measured from morning-stiffness-related BASDAI scores. The remaining domain could not show the specified deterioration.

This endpoint combines several dimensions of ankylosing spondylitis rather than relying on a single symptom or examination measure. As a general statistical and clinical measurement principle, a composite response can represent improvement across different aspects of a condition, while its interpretation depends on the precise response rule. Here, the rule requires improvement in multiple domains and guards against worsening in the remaining domain.

The registry record reports a number of participants meeting the criterion, with 154 of 229 in the adalimumab group and 35 of 115 in the placebo group. Missing responses in the primary analysis were classified as non-responses. That imputation rule is part of the endpoint's reported analysis and means the presented counts reflect both observed response status and the specified handling of missing responses.

7. Results Posted in the Registry

• Adalimumab/Adalimumab: 67.2% (154/229) versus 30.4% (35/115) on control; risk difference 36.8 percentage points (95% CI 26.4 to 47.2), risk ratio 2.21 (1.65–2.96); unadjusted two-proportion 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.

Number of Participants Meeting the ASAS20 Response Criteria

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Adalimumab/Adalimumab: 80.4% (180/224) versus 75.2% (85/113) on control; risk difference 5.1 percentage points (95% CI -4.4 to 14.6), risk ratio 1.07 (0.94–1.21); unadjusted two-proportion z-test p = 0.278.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Adalimumab/Adalimumab and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants Meeting the ASAS40 Response Criteria

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Adalimumab/Adalimumab: 44.5% (102/229) versus 9.6% (11/115) on control; risk difference 35.0 percentage points (95% CI 26.6 to 43.4), risk ratio 4.66 (2.61–8.32); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Adalimumab/Adalimumab than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Participants Meeting the ASAS5/6 Response Criteria

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Adalimumab/Adalimumab: 55.9% (128/229) versus 12.2% (14/115) on control; risk difference 43.7 percentage points (95% CI 34.9 to 52.5), risk ratio 4.59 (2.77–7.60); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Adalimumab/Adalimumab than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The posted secondary results with comparative estimates include the Week 24 ASAS20 response and Week 12 ASAS40 and ASAS5/6 responses. The two Week 12 response outcomes point in the same direction as the primary Week 12 ASAS20 result, while the Week 24 ASAS20 comparison is less conclusive statistically. This overall pattern is compatible with the primary result, but the secondary endpoints measure different response thresholds or occur in a different treatment context.

Week 12 ASAS40 and ASAS5/6 are assessed during the blinded comparison, so they provide related evidence under the original randomized treatment assignments. ASAS40 applies a different response definition from ASAS20, and ASAS5/6 is another distinct criterion. Their findings should be understood as supportive context rather than replacements for the prespecified primary outcome.

At Week 24, both groups had received open-label adalimumab from Week 12. The comparison at that time therefore does not preserve the same placebo-controlled contrast as the primary endpoint. The Week 24 results describe outcomes by the earlier treatment sequence, not an ongoing blinded assignment to adalimumab versus placebo.

The registry lists 21 secondary outcomes as posted, while only a subset has comparative numerical results in the registry record described for this analysis. The record does not report an adjustment for multiple testing. As a general statistical point, repeated testing across outcomes can make nominal p-values less persuasive as confirmatory evidence unless the testing plan controls the overall error rate. The secondary findings should consequently carry less weight than the designated primary endpoint, especially when the full multiplicity strategy is not reported.

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

• Number of Participants Meeting the ASAS20 Response Criteria
• Number of Participants Meeting the ASAS40 Response Criteria
• Number of Participants Meeting the ASAS40 Response Criteria
• Number of Participants Meeting the ASAS5/6 Response Criteria
• Number of Participants Meeting the ASAS5/6 Response Criteria
• Number of Participants With ASAS Partial Remission
• Number of Participants With ASAS Partial Remission
• Change From Baseline in Patient Global Assessment of Disease Activity

9. Statistical Interpretation

10. Statistical Methods Explained

The primary comparison is binary: each participant either met the ASAS20 response criterion or did not. The results give a responder count and analysis denominator for each group. A risk difference compares the response proportions between groups by subtracting one group proportion from the other. In this case, the unadjusted risk-difference estimate and its confidence interval are calculated from the posted summary counts, not from an adjusted model.

What the risk difference means

As a general statistical explanation, a risk difference expresses the absolute separation between two event proportions on the proportion scale. A value of zero represents equal proportions. A positive value in this comparison indicates a greater observed response proportion in the adalimumab group than in the placebo group. This measure answers a different question from a relative measure, such as a risk ratio, which compares proportions by division. The registry record provides a risk-difference estimate and also reports relative measures, but the absolute contrast is useful for describing how far apart the group response proportions are.

What the confidence interval contributes

A confidence interval gives a range of estimates compatible with the data and the method used to calculate it. In repeated use of the same procedure under its assumptions, intervals constructed this way would cover the underlying quantity at the stated confidence level at the procedure's nominal frequency. It is not a range containing a fixed percentage of individual participant outcomes, and it is not a probability statement that the true effect lies in this particular interval. For the primary comparison, the posted interval does not include zero, consistent with the small reported p-value.

How to read the reported test

The registry record identifies a chi-squared test for the primary comparison and reports p < 0.001. As a general explanation, a chi-squared test evaluates whether the observed distribution of categorical outcomes is compatible with a null hypothesis of no association or group difference, according to the test's setup. A small p-value indicates that data at least this discrepant from the null would be unusual if the null and the test assumptions held. It does not measure the probability that treatment assignment had no effect, and it does not establish clinical importance.

The unadjusted calculations use the posted summary counts and do not incorporate covariates or any adjustment for the trial's design beyond the comparison represented by the groups. The sponsor's reported analysis and the recalculated summary-statistic comparison agree in their broad inference for the primary result; the registry record does not indicate a discrepancy. The sponsor's own analysis remains the source for the trial's reported test.

Missing responses and analysis population

The primary analysis population includes randomized participants who received at least one dose of double-blind study drug. This is the registry's definition of its intent-to-treat analysis set; it should not be assumed to mean every randomized participant regardless of treatment receipt. The specified non-responder imputation treats a missing response as a non-response. As a general explanation, such a rule can make the analysis sensitive to missingness because it assigns an outcome rather than estimating it from observed data. The registry record does not report the number of missing primary responses or alternative missing-data analyses.

Why binary outcomes can be informative

A response count is easy to interpret as the number meeting a prespecified threshold, but it compresses information. Participants just short of the threshold and those with little change may both be classified as non-responders, while degrees of improvement among responders are not conveyed by the count. The registry lists other outcomes, including change in patient global assessment, but the associated results are not all included in the registry record described for this analysis. Consequently, the primary count should be read as evidence about this defined response criterion, not as a complete description of every aspect of disease activity.

General statistical caution also applies to the secondary outcomes. If many outcomes are tested, the chance of at least one nominally unusual result can increase, depending on the testing structure. The registry record does not report a multiplicity adjustment or a hierarchical testing strategy. The posted secondary p-values therefore should not be interpreted as if they necessarily preserve the same overall error rate as a single prespecified test.

11. Confidence Intervals and Precision

The primary risk-difference confidence interval is reported at the 95% confidence level and lies above zero. That interval conveys uncertainty about the size of the unadjusted contrast: it is not limited to the point estimate, and the plausible values span a range. The interval's exclusion of zero agrees with the reported primary p-value of < 0.001, but the two summaries answer related rather than identical questions.

Precision depends on both the estimate and its uncertainty. As a general explanation, more information can narrow an interval, while sparse outcomes or substantial variation can leave a wider range of compatible effects. The primary results include 229 participants in the adalimumab group and 115 in the placebo group, with 154 and 35 responders, respectively. The comparison is therefore estimated from groups of unequal size, a feature relevant to its uncertainty.

The Week 24 ASAS20 comparison is less decisive statistically: its posted confidence interval includes zero, and its unadjusted p-value is 0.278. This does not establish equivalence or prove the absence of a difference. It indicates that the posted interval includes both no difference and values on either side of zero under the calculation. It also concerns a different treatment period, after both groups received open-label adalimumab.

Confidence intervals do not account automatically for every source of uncertainty. The registry record does not report whether secondary comparisons were adjusted for multiplicity, and the unadjusted calculations do not address unreported design details. Precision should therefore be considered alongside the outcome definition, analysis population, treatment sequence, and the limits of the registry record.

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, not total events. They are illustrations based on the observed effect, not the trial's original design calculations. The registry record does not report the original sample-size justification or its assumptions. The planning illustration assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; each planning scenario uses the stated fraction of the observed effect to be detected.

The 80% power column gives the illustrative number of participants per arm for a design with 80% power to detect the specified effect under those assumptions. The 90% power column gives the corresponding number per arm for a design with 90% power. Power is the chance of rejecting the null hypothesis under a specified alternative effect and the stated model assumptions, not a guarantee of a result.

For the primary outcome, the planning display gives 28 participants per arm for 80% power and 37 for 90% power at 100% of the observed effect; for 75% of the observed effect, the figures are 50 and 66; for 50% of the observed effect, they are 110 and 147. Smaller effects need more participants to detect under the same assumptions. These are planning illustrations and are not observed power.

The illustration is a simplified calculation from the observed summary data. It does not show that the completed trial was designed using these assumptions, and it should not be treated as a reconstruction of the protocol's justification.

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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.304; treatment proportion p₁ = 0.672; average p̄ = 0.488.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.7069 = 1.3855.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6572 = 0.5531.
4. n = (1.3855 + 0.5531)² / (0.3681)² = 27.7, rounded up to 28 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.304347826086957                          # control proportion
p1 <- 0.672489082969432                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1114880)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 28 (80% power), 37 (90% power)
 75% of observed effect: n per arm = 50 (80% power), 66 (90% power)
 50% of observed effect: n per arm = 110 (80% power), 147 (90% power)
power.prop.test: 27.7 
Simulated power at n = 28 per arm: 0.795 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry record reports a chi-squared analysis of the primary comparison, with p < 0.001 at the 95% confidence level. A separate unadjusted re-calculation from the posted summary counts gives the same broad statistical conclusion: the primary risk-difference interval excludes zero, and its unadjusted p-value is < 0.001. The record marks no discrepancy between the posted result and the re-calculation.

The recalculation is a simple comparison of the posted group counts. It does not replace the sponsor's analysis or reproduce any underlying participant-level model. Where the sponsor's own analysis is reported, it takes precedence as the trial's analysis. The registry record does not provide further detail about covariate adjustment, test implementation, or a fuller statistical analysis plan.

The numerical p-value is reported with slightly different spacing in the two presentations, but both state p < 0.001. The interpretation should remain anchored to the reported test and the size and uncertainty of the group contrast, rather than treating agreement in p-value notation as proof that every analytical choice was identical.

15. Multiplicity, Missing Data and Analysis Populations

The primary outcome has a defined analysis population and missing-response rule. The intent-to-treat analysis set included randomized participants who received at least one dose of double-blind study drug. The registry record states that a missing primary response was imputed as non-response. It does not report how many primary observations were missing, the reasons for missingness, or sensitivity analyses using other assumptions.

As a general explanation, missing-data handling matters because the observed outcome may differ systematically from the outcome that would have been recorded if follow-up were complete. Non-responder imputation is transparent as a classification rule, but its consequences depend on the amount and pattern of missing data. Without the missing counts and alternative analyses, the sensitivity of the primary result to that rule cannot be assessed from the registry record.

The record reports multiple secondary outcomes and lists 21 posted secondary outcomes. It does not report a multiplicity correction, a hierarchy among endpoints, or an adjustment strategy for the family of secondary tests. As a general statistical matter, conducting multiple tests can increase the chance of obtaining one or more small p-values by chance when all null hypotheses hold. A nominal p-value for a secondary outcome may therefore offer weaker confirmatory evidence than a single prespecified primary test.

The record does not report the original sample-size justification, an interim analysis plan, or the complete statistical analysis plan. Those details are not inferable from the posted endpoint counts or the reported chi-squared test. Accordingly, the analysis can describe the stated population, imputation rule, and available results, but it cannot establish whether other planned methods were applied or whether the outcome reporting follows a prespecified multiplicity strategy.

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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hepatitis viral (0.9%), fibroadenoma of breast (0.9%), intraductal papilloma of breast (0.9%), peritoneal tuberculosis (0.4%), pulmonary tuberculosis (0.4%).

For Period 1, the registry reports 1 serious adverse event among 229 participants in the adalimumab group and 1 among 115 participants in the placebo group. For Period 2, it reports 3 among 224 participants in the Adalimumab/Adalimumab group and 1 among 113 participants in the Placebo/Adalimumab group. These are counts of participants affected and participants at risk as presented in the registry record; they are not a basis for a randomized placebo comparison in Period 2, when both groups received open-label adalimumab.

The listed serious adverse-event terms include hepatitis viral, fibroadenoma of breast, and intraductal papilloma of breast at 0.9% each, and peritoneal tuberculosis, pulmonary tuberculosis, and tuberculosis pleurisy at 0.4% each. These are the terms and percentages named in the record, not a complete account of all clinical details or a basis for attributing causation.

Deaths are not reported in the registry record. The safety counts should be read alongside the treatment periods and exposure groups, and should not be treated as a complete assessment of comparative safety or individual risk.

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

The primary result shows a clear statistical separation in the observed Week 12 ASAS20 response counts between the randomized groups. The registry reports 154 responders among 229 participants assigned to adalimumab and 35 among 115 assigned to placebo, with a chi-squared p-value of < 0.001. The unadjusted confidence interval for the risk difference excludes zero. Together, these summaries describe a group-level difference for the defined response criterion during the blinded comparison.

That finding does not establish that every participant experienced improvement, nor does a binary response count capture the full range of individual outcomes. It also does not alone determine the clinical importance of the difference, since statistical evidence and clinical importance are distinct questions. The endpoint aggregates response across specified domains and classifies each participant according to a threshold rule.

The result applies to the study population and treatment sequence recorded: adult Chinese participants with active ankylosing spondylitis and the stated prior NSAID response or intolerance criteria, with a blinded comparison through Week 10 and assessment at Week 12. It should not automatically be generalized to people outside that population or to different treatment circumstances.

The Week 24 results should not be taken as a placebo-controlled follow-up, because both groups received open-label adalimumab from Week 12 to Week 24. Secondary endpoint findings add context but have less confirmatory weight because the registry record does not report a multiplicity strategy. The safety figures are counts within treatment periods, and they do not by themselves establish causation or comparative safety.

Overall, the posted data support a statistical difference in the primary outcome as analyzed. They do not answer every question about durability, mechanism, individual benefit, or long-term safety. Those conclusions would require evidence and analyses beyond the information reported in the registry record.

18. Why This Trial Matters Statistically

This trial illustrates several core principles of clinical-trial interpretation. First, a prespecified primary endpoint gives the main comparison a clear focus. Here, ASAS20 is a binary response based on improvement across multiple domains, making the result interpretable as a count of participants meeting a defined criterion rather than as a change in a single measure.

Second, analysis depends on the treatment timeline. The Week 12 primary assessment follows the blinded treatment period, while both groups receive open-label adalimumab from Week 12 onward. That distinction is essential: later comparisons cannot be described as continued randomized treatment against placebo when treatment assignment has converged.

Third, the primary result is stronger when expressed with both a point comparison and uncertainty. The reported p-value addresses compatibility with a null comparison under the test, while the confidence interval describes the range of unadjusted effects compatible with the data and method. These statistics complement rather than replace the responder counts and endpoint definition.

Finally, the record highlights how omissions shape interpretation. It reports a missing-response rule but not the number missing or sensitivity analyses. It lists numerous secondary outcomes without reporting a multiplicity strategy, and it does not report the original sample-size justification. A statistical reading must distinguish what is documented from what cannot be established. This disciplined approach keeps the primary finding in view without overstating the certainty or scope of conclusions.

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 registry record provides a defined primary analysis population and states that missing primary responses were imputed as non-responses, but it does not report the number of missing responses or sensitivity analyses. The influence of missing data on the primary estimate therefore cannot be assessed from the record alone.

The record does not report the original sample-size justification, the full statistical analysis plan, or an interim analysis plan. The available planning illustration is calculated from the observed effect and should not be mistaken for the trial's original design rationale. Randomization details and the identities of those included under the triple-masking designation are also not reported in the registry record.

Many secondary outcomes are listed, but comparative numerical results are available for only a subset in the registry record described for this analysis. The registry record does not report a multiplicity adjustment or hierarchy for those outcomes. Secondary p-values therefore should be interpreted cautiously and should not be treated as equivalent in evidential status to the designated primary test.

The study's treatment sequence also limits later comparisons. After Week 12, both groups received open-label adalimumab, so the Week 24 results do not preserve the original placebo contrast. Finally, the safety information presented consists of period-specific counts and selected serious-event terms. Deaths are not reported in the registry record, and the available information is not a complete account of safety outcomes or causal attribution.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Efficacy and Safety of Adalimumab in Adult Chinese Subjects With Active Ankylosing Spondylitis — NCT01114880.
• Registry record last updated 2011-12-01; status last verified 2011-11.
• Results first posted 2011-11-04.
• 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

NCT01114880 is a completed Phase 3 randomized, triple-masked, parallel-group, placebo-controlled, multicenter study of adalimumab in adult Chinese participants with active ankylosing spondylitis. The registry reports enrollment of 344 participants and a blinded treatment period from Week 0 to Week 10, followed by open-label adalimumab from Week 12 to Week 24 in both groups.

The primary Week 12 ASAS20 result was 154 of 229 participants in the Adalimumab/Adalimumab group and 35 of 115 in the Placebo/Adalimumab group. The registry reports a chi-squared p-value of < 0.001. Missing responses in the primary analysis were imputed as non-responses.

The posted secondary results include Week 12 ASAS40 and ASAS5/6 outcomes and Week 24 ASAS20. Because both groups received open-label adalimumab after Week 12, the later outcome is not a continued placebo-controlled comparison. The record does not report a multiplicity strategy, the original sample-size justification, or the full statistical analysis plan.