Safety and Efficacy of MP-214 in Patients With Schizophrenia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy of MP-214 in Patients With Schizophrenia (NCT01625000), a randomized phase 2, phase 3 study. The primary outcome is Change in the Positive and Negative Syndrome Scale (PANSS) Total Score at Week 6.

2. Clinical Question

The clinical question concerns both the size and precision of the observed score changes. A more negative change represents a larger reduction in PANSS total score over the period, but the comparison with placebo is central: within-group change alone cannot distinguish a treatment-group pattern from change also observed in the placebo group. The registry record gives arm-level least-squares means and standard errors, and recalculated unadjusted comparisons with placebo. It does not report sponsor analyses for these outcomes. The clinical question is therefore best read as a comparison of posted summaries, rather than as a complete account of a prespecified statistical testing strategy.

3. Trial Design

This completed study is identified as NCT01625000 and titled “Safety and Efficacy of MP-214 in Patients With Schizophrenia.” The official title describes a double-blind, placebo-controlled study. The registry lists randomized allocation, quadruple masking and a parallel model. It lists both Phase 2 and Phase 3.

The study objective was to evaluate the efficacy, safety and tolerability of MP-214 relative to placebo in patients with acute exacerbation of schizophrenia. The listed groups received MP-214 3mg, MP-214 6mg, MP-214 9mg, Risperidone 4mg or placebo. Although the registry identifies the study as randomized and parallel, the specific allocation procedure and allocation ratio are not reported in the registry record. Arm descriptions are blank, so additional details about the regimens are not reported in the registry record.

The record lists enrollment of 512, a study start of 2012-05 and primary completion of 2015-08, with status completed. The primary outcome is change in PANSS total score from baseline to Week 6. The listed secondary outcome is change in Clinical Global Impression-Severity score at Week 6. The endpoint summaries use observed cases and exclude missing values. The reasons for missing measurements, participant flow through follow-up and details of the analysis population are not reported in the registry record. The record also does not report the original sample-size justification or the trial’s planned statistical analysis methods.

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: Four subjects withdrew from the study before the start of the study medication after being assigned to the treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: For OC (Observed Case) analysis, the Missing Values were Not included.

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Change in the Positive and Negative Syndrome Scale (PANSS) Total Score at Week 6, measured over Baseline and Week 6.

The primary endpoint is change in the Positive and Negative Syndrome Scale (PANSS) total score at Week 6, measured from baseline. PANSS is a 30-item rating scale assessing positive and negative symptom syndromes in schizophrenia. Each item is rated on a 7-point scale from 1 (absent) to 7 (extreme). The total ranges from 30 to 210, and higher totals indicate greater symptom severity.

Because the outcome is a continuous score, its group summary describes the mean change rather than the number of participants meeting a threshold. A negative change indicates a decrease in total score; a larger negative value corresponds to a greater decrease in the measured score. The endpoint is useful for comparing the degree of symptom-score change between groups over the same follow-up period. It does not, by itself, describe every aspect of a participant’s clinical state or establish how meaningful a particular score change is to patients.

The registry reports least-squares means and standard errors for observed cases, excluding missing values. The reported endpoint summaries therefore describe the recorded Week 6 measurements in the analysis groups, not an analysis that includes missing measurements. The registry record does not report how missing observations were handled beyond their exclusion, whether other analysis populations were used, or how the least-squares means were estimated.

7. Results Posted in the Registry

• MP-214 3mg: mean -10.40 versus -9.50 on control; difference -0.90 (95% CI -6.58 to 4.78), standardized effect d = -0.05; z-test p = 0.756.
• MP-214 6mg: mean -13.80 versus -9.50 on control; difference -4.30 (95% CI -9.98 to 1.38), standardized effect d = -0.24; z-test p = 0.138.
• MP-214 9mg: mean -14.00 versus -9.50 on control; difference -4.50 (95% CI -11.52 to 2.52), standardized effect d = -0.26; z-test p = 0.209.
• Risperidone 4mg: mean -20.20 versus -9.50 on control; difference -10.70 (95% CI -17.88 to -3.52), standardized effect d = -0.60; z-test p = 0.003.

8. Secondary Efficacy Endpoints

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

Change in the Clinical Global Impression-Severity (CGI-S) Score at Week 6

• 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:
  • MP-214 3mg: mean -0.70 versus -0.60 on control; difference -0.10 (95% CI -0.38 to 0.18), standardized effect d = -0.12; z-test p = 0.480.
  • MP-214 6mg: mean -0.80 versus -0.60 on control; difference -0.20 (95% CI -0.48 to 0.08), standardized effect d = -0.23; z-test p = 0.157.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between MP-214 3mg and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between MP-214 6mg and the control. The interval gives the range of effects that remain compatible with the data.

The registry record lists one secondary endpoint: change in CGI-S score at Week 6. Its group summaries describe decreases across the posted groups, and the available recalculated comparisons point in the same broad direction as the primary outcome in that some active-group mean changes are more negative than placebo. This provides a complementary symptom-severity measure, but the secondary measure is not a substitute for the primary PANSS outcome.

The breadth of the secondary evidence is limited. The registry lists one secondary outcome, while reported sponsor analyses are absent. Recalculated comparisons are available for MP-214 3mg and 6mg; the registry record does not report recalculated comparisons for every listed group on this secondary endpoint. The estimates therefore do not form a complete confirmatory set across all treatment groups.

Unadjusted secondary results carry less inferential weight because multiple outcomes and treatment comparisons can create more opportunities for apparently notable findings by chance. The registry record does not report a multiplicity adjustment, a hierarchy of endpoints or a strategy for treating secondary outcomes as confirmatory. The CGI-S pattern is best considered alongside, rather than as independent proof reinforcing, the primary result. It can describe whether a separate rating measure has a broadly similar pattern, but it cannot resolve the uncertainty in the primary comparisons or establish a prespecified overall conclusion.

Interpretation is also bounded by the reported observed-case approach. Missing values were excluded, and the record does not describe their frequency or handling beyond that. Thus, the secondary summaries characterize the analyzed observations as posted. They do not establish whether missing measurements affected the apparent consistency between outcomes.

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

• Change in the Clinical Global Impression-Severity (CGI-S) Score at Week 6

9. Statistical Interpretation

10. Statistical Methods Explained

What does a least-squares mean describe?

A mean is a summary of a continuous outcome across the observations in a group. The registry identifies the primary and secondary summaries as least-squares means. In general, a least-squares mean is an estimated group mean from a statistical model, and its interpretation depends on the model and covariates used. The model details for these reported estimates are not reported in the registry record, so the term should not be taken to imply a particular adjustment scheme. The posted arm summaries are change scores at Week 6, with a standard error accompanying each mean.

How should the change and the comparison be read?

The primary endpoint is a change from baseline, so negative values represent a decrease in PANSS total score. A mean difference compares the change in one group with the change in placebo. It is calculated in the direction of the named treatment group minus placebo. A negative difference therefore indicates a more negative average change in that treatment group, while a positive difference would indicate a less negative or more positive change relative to placebo. The difference is expressed in PANSS score units, not in a standardized effect scale.

The comparison estimates and intervals presented with the posted results are recalculated, unadjusted comparisons from the arm summaries. The calculations use approximate standard deviations inferred from the reported standard errors, as marked in the calculation record. This is not the same as a reported sponsor model, and the registry record has no reported analyses for these outcomes. Because the recalculation relies on summary statistics and approximations, it should be treated as a useful descriptive comparison, not as a replacement for the trial’s own prespecified analysis. The discrepancy indicator is false, so the record does not flag a discrepancy between a sponsor analysis and these recalculations.

What does a standard error tell the reader?

A standard error describes the estimated sampling variability of a mean: in general, it indicates how much an estimate might vary across repeated samples under the statistical assumptions used. It is not the spread of individual participant scores. The standard errors reported for the primary arm means are 2.0, 2.0, 2.9, 3.0 and 2.1 for MP-214 3mg, MP-214 6mg, MP-214 9mg, Risperidone 4mg and placebo, respectively. A larger standard error generally means less precision for that mean, although precision also depends on the scale and analysis. The registry record does not provide individual-level data or model details that would allow an independent assessment of those standard errors.

What does an interval around a difference add?

An interval expresses a range of values that are reasonably compatible with an estimated difference under the calculation’s assumptions and chosen confidence procedure. It makes uncertainty visible in the same score units as the estimate. If an interval includes zero, it includes no difference as one plausible value; if it lies entirely on one side of zero, the range excludes no difference under that procedure. Neither situation establishes clinical importance. The interval widths also show why an estimate should not be read only by its point value: relatively broad ranges allow a variety of possible differences. The confidence level for the recalculated intervals is not reported in the registry record.

What do the p-values represent?

The reported comparison p-values are unadjusted. In general, a p-value measures how incompatible the observed data are with a specified null hypothesis under the statistical model; it is not the probability that the null hypothesis is true, nor a measure of treatment effect size. These values do not account for testing several dose groups, the active comparator and more than one endpoint. No multiplicity adjustment is reported. As a result, the p-values should be considered alongside effect estimates and uncertainty, not used alone to label a finding as definitive. The registry record does not report the complete hypothesis-testing plan.

What can be inferred from the analysis population?

The endpoint population is described as observed case, with missing values not included. This means the reported summaries use available observed measurements rather than treating missing values as observed outcomes. In general, excluding missing observations can affect interpretation if the availability of measurements is related to outcome or treatment group. The registry record does not report reasons for missingness, a method for imputing missing values, sensitivity analyses, or other analysis populations. It is therefore not possible to establish from the record whether missingness could have influenced the estimates.

The registry describes randomization, which in general is intended to support fair comparisons by allocating participants without basing assignment on their prognosis. That design feature does not remove the need to understand the analysis population, outcome collection and statistical plan. Details of the randomization method, concealment, covariate adjustment, handling of protocol deviations and any interim analyses are not reported in the registry record. The site’s recalculations are simple unadjusted comparisons based on posted summary statistics; they do not reconstruct unreported trial methods.

11. Confidence Intervals and Precision

Precision is conveyed by the range around each recalculated difference, not just by the point estimate. For MP-214 3mg versus placebo, the difference was -0.9, with an interval from -6.584 to 4.784. For MP-214 6mg, it was -4.3, with an interval from -9.984 to 1.384. For MP-214 9mg, it was -4.5, with an interval from -11.52 to 2.518. Each of these intervals includes zero, so the posted calculations leave no difference among the values compatible with the interval.

For Risperidone 4mg versus placebo, the recalculated difference was -10.7, with an interval from -17.88 to -3.523. This interval lies below zero, indicating a more negative change for that group within the range calculated. The interval is still a range of plausible values under the calculation, not a guarantee that the true difference falls within it or that the difference has a particular clinical importance.

The intervals are unadjusted recalculations using approximate standard deviations derived from standard errors. The registry record does not report the confidence level for these intervals or sponsor-run comparisons. Their precision should therefore be interpreted in light of the calculation method and the analysis counts, which vary by group. A narrow interval would indicate a more precise estimate than a wide one, but precision does not determine whether an effect matters clinically. The intervals also do not account for the uncertainty introduced by testing multiple groups and outcomes.

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 for participants per arm, not total events. The event-count convention for time-to-event outcomes does not apply to this continuous endpoint. The illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms and a normal approximation. It uses the observed effect as its reference and considers planning for 100%, 75% or 50% of that observed effect. These are illustrative assumptions, not the trial’s original design assumptions; the original sample-size justification is not reported in the registry record.

The 80% power column gives the per-arm sample size that the stated planning calculation associates with an 80% chance of detecting the selected effect under its assumptions. The 90% power column gives the corresponding per-arm number for a 90% chance. Power is a property of a proposed design under specified assumptions, not a measure of whether the completed trial’s result is true or important. The figures are planning illustrations based on an observed effect, not observed power.

Rows planning for a smaller fraction of the observed effect require more participants per arm. This follows because smaller differences are harder to distinguish from sampling variability when other assumptions are held fixed. The values should be read as hypothetical design requirements for the specified two-arm comparison, not as an assessment of the original five-group trial’s adequacy. The registry record does not report the original assumptions, target effect, planned power or allocation details that informed the actual enrollment.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.900; pooled standard deviation σ = 17.678.
2. n = 2 × (1.96 + 0.842)² × 17.678² / -0.900² = 6,056.8, rounded up to 6,057 participants per arm for 80% power.

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

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.9                      # observed difference in means
sigma <- 17.6784776332288                     # 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(1625000)
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 = 6,057 (80% power), 8,109 (90% power)
 75% of observed effect: n per arm = 10,768 (80% power), 14,415 (90% power)
 50% of observed effect: n per arm = 24,228 (80% power), 32,434 (90% power)
power.t.test: 6057.7 
Simulated power at n = 6,057 per arm: 0.800 (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 has several treatment groups and more than one outcome, creating the possibility of multiple statistical comparisons. The registry record does not report a multiplicity adjustment, a primary comparison hierarchy, or rules for interpreting results across doses and endpoints. The recalculated p-values are unadjusted and should not be treated as if they controlled the chance of false-positive findings across the full set of comparisons. A prespecified testing sequence or adjustment could change the interpretation, but such a plan is not reported in the registry record.

The primary endpoint summaries use observed cases, and the record explicitly states that missing values were not included. It does not report the amount or pattern of missing data by outcome, the reasons measurements were absent, or whether missingness differed by group. It also does not report imputation, sensitivity analyses or an alternative analysis population. These gaps matter because available-case results can be affected when the likelihood of having an observed measurement is related to treatment or outcome.

The registry record does not report the trial’s full statistical analysis plan, covariate adjustment, interim analyses, stopping rules, protocol-deviation handling or the original sample-size justification. Those details should not be inferred from the posted arm summaries or planning illustrations. Although the study is listed as randomized and quadruple masked, the record does not provide the operational details of allocation or masking. The stated study design is useful context, but it does not fill in missing analysis specifications.

The site’s recalculated comparisons are unadjusted estimates based on posted summary statistics, with approximate standard deviations inferred from standard errors. They are not sponsor-reported analyses. The registry reports no analyses, so there is no sponsor analysis in the record to compare against the recalculations. The calculations can make group contrasts easier to interpret, but they cannot supply missing prespecified methods or correct for unreported multiplicity and missing-data decisions.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: schizophrenia (10.5%), akathisia (1.8%), extrapyramidal disorder (1.8%), suicide attempt (1.8%), agitation (1.5%).

The registry reports serious adverse event counts and the number at risk for each group. Serious adverse events affected 12 of 126 participants in MP-214 3mg, 16 of 133 in MP-214 6mg, 4 of 67 in MP-214 9mg, 2 of 56 in Risperidone 4mg and 14 of 126 in placebo. These are group-specific counts; they should be read in relation to each group’s reported at-risk count, not treated as counts from equally sized groups.

The most frequently listed serious terms include Schizophrenia at 10.5%, followed by Akathisia, Extrapyramidal disorder and Suicide attempt at 1.8% each, then Agitation and Suicidal behaviour at 1.5% each. The registry record does not provide further details about event timing, severity beyond the serious-event classification, attribution or the number of events per affected participant. Death counts are not reported in the registry record.

These figures describe reported serious events in the listed groups. They do not, on their own, establish comparative safety or explain whether events were considered related to study treatment. The registry record also lists other adverse events, but the serious-event counts should not be combined with those figures.

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

The posted results describe changes in symptom-rating scores among observed cases through Week 6. The PANSS group means decreased from baseline in all listed groups, including placebo, and the estimated differences from placebo are not equally precise. Three MP-214 recalculated intervals include zero; the Risperidone 4mg interval does not. These are statements about the posted estimates and their unadjusted recalculations, not definitive claims about treatment effects.

A difference in average score does not mean every participant changed by that amount. Group means can conceal varied individual responses, and the registry record does not report individual-level outcomes or the distribution of participant changes. Nor does the numerical size alone establish whether a change is clinically important. The registry record does not supply a threshold for meaningful change or a patient-centered interpretation of the score differences.

The results do not show what would have happened to the same participants under another assignment. Randomization is a design feature intended to support group comparisons, but conclusions still depend on the analysis, follow-up, missing data and prespecified testing approach. Those details are incompletely reported. The comparisons presented are unadjusted recalculations from summary statistics, not reported sponsor analyses, and multiple comparisons are not addressed in the posted results.

The data also do not establish long-term outcomes: the primary endpoint is measured at Week 6, and longer-term endpoint results are not reported in the registry record. The safety counts describe reported events but do not establish causality or quantify every possible harm. The appropriate interpretation is limited to the posted short-term outcome summaries and safety counts, with uncertainty and reporting gaps kept in view.

17. Why This Trial Matters Statistically

This trial illustrates why a randomized, placebo-controlled design and clear between-group comparisons matter when interpreting change over time. The placebo group also had a negative mean PANSS change, so within-group decreases cannot be read as treatment-versus-placebo differences. The relevant comparison is the estimated change contrast, together with its uncertainty.

It also demonstrates the importance of separating point estimates from precision. The primary comparisons vary in magnitude, while their intervals show that the estimates do not all support the same degree of certainty. An unadjusted p-value alone cannot convey the range of compatible differences or clinical importance. Reporting estimates and intervals in the original score units helps readers understand what the comparisons represent.

The record highlights a second statistical issue: enrollment and endpoint analysis counts are not interchangeable. The study enrollment is reported as 512, whereas the endpoint summaries use observed cases and list different group counts. Without participant flow and details about missingness, readers cannot determine how the observed-case analysis relates to the randomized population.

Finally, the absence of reported sponsor analyses, multiplicity methods and the original sample-size justification limits the inferential story available from the record. Planning illustrations can clarify how design requirements depend on assumed effects, but they do not reveal how the trial was originally planned or whether its design matched those illustrations. Together, these features show why transparent reporting of the analysis plan, missing-data approach and full set of comparisons is essential to judging clinical trial evidence.

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 primary endpoint is observed-case only, with missing values excluded. The registry record does not report how many endpoint measurements were missing by group, why they were missing, or whether missingness was related to outcome. It also does not report imputation or sensitivity analyses. These omissions limit assessment of how well the reported means represent the randomized groups.

Arm counts for the posted primary outcome differ, and the record does not give participant flow or explain those analysis counts. Overall enrollment of 512 is not the same as the count contributing to each endpoint summary. The record does not report details about withdrawals, adherence or protocol deviations that might help explain the difference.

The comparison estimates are recalculated from posted summaries, with approximate standard deviations inferred from standard errors. The registry reports no sponsor analyses for these endpoints. The record does not specify the confidence level for the recalculated intervals, the full model used to generate the least-squares means, or whether covariates were included. Consequently, the recalculations should not be treated as a reconstruction of an unreported analysis plan.

Multiplicity is another limitation: no adjustment or comparison hierarchy is reported despite multiple groups and outcomes. The original sample-size assumptions and justification are also not reported; the planning figures are based on observed effects and stated illustrative assumptions, not on the trial’s original design. Finally, the primary outcome is at Week 6, and longer-term efficacy and safety outcomes are not reported in the registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Safety and Efficacy of MP-214 in Patients With Schizophrenia — NCT01625000.
• Registry record last updated 2026-01-05; status last verified 2025-12.
• Results first posted 2021-04-12.
• 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

NCT01625000 is a completed randomized, quadruple-masked, parallel, placebo-controlled study listed as Phase 2 and Phase 3. It evaluated MP-214 in patients with acute exacerbation of schizophrenia, with groups receiving MP-214 3mg, 6mg or 9mg, Risperidone 4mg or placebo. Enrollment was 512.

The primary outcome was change in PANSS total score from baseline to Week 6. The posted observed-case means decreased in all groups. Recalculated unadjusted comparisons with placebo show intervals that include zero for each MP-214 dose and an interval below zero for Risperidone 4mg. The registry record lists one secondary outcome, change in CGI-S at Week 6, and reports group-specific serious adverse event counts.

The registry record does not report sponsor analyses, a multiplicity strategy, the original sample-size justification or details of missing-data handling beyond exclusion of missing values. Interpretation should therefore remain focused on the posted summaries and their uncertainty.