Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of MLN3126 in Healthy Japanese and Non-Japanese Participants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of MLN3126 in Healthy Japanese and Non-Japanese Participants (NCT02209506), a randomized phase 1 study. The primary outcome is Number of Participants Reporting One or More Treatment-emergent Adverse Events (TEAEs).

2. Clinical Question

The design was intended to assess safety and drug handling following single and multiple oral doses in healthy participants. Its ascending-dose cohorts and placebo groups make the safety counts interpretable within the particular arms recorded. However, the available primary outcome is a count of participants with at least one treatment-emergent adverse event, not a full description of the type, severity, timing, or duration of every event. The registry record does not report a formal treatment-effect estimate or uncertainty interval for a comparison between dose and placebo.

3. Trial Design

This was a randomized, quadruple-masked, parallel-group phase 1 study. It is described as double-blind and placebo-controlled in its official title, and as having sequential cohorts with ascending multiple oral doses. Takeda is listed as the sponsor. The recorded enrollment was 23 participants, and the study status is terminated. The study start is recorded as 2014-07 and primary completion as 2014-09.

The study’s stated purpose was to evaluate the safety and tolerability of single and multiple oral dosing of MLN3126 in ascending doses in healthy non-Japanese and Japanese participants. The cohort descriptions include MLN3126 doses of 100 mg, 300 mg, and 800 mg, as well as later cohorts whose dose was to be determined based on data from an earlier cohort. Each described active-treatment schedule begins with a dose on Day 1, followed by a 7 day washout period and once daily dosing for 7 days on Days 9 through 15. Matched placebo tablets are described for the corresponding cohorts.

The primary outcome was the number of participants with one or more treatment-emergent adverse events. The registry defines a treatment-emergent adverse event as an adverse event with onset after receiving study drug, with the assessment timeframe extending from baseline through 7 days after the last dose, identified as Day 22. Secondary outcomes include pharmacokinetic measures for MLN3126 and its metabolite, including maximum plasma concentration, time to maximum concentration, area under the plasma concentration-time curve, apparent oral clearance, and terminal elimination half-life.

The registry record does not report why the study was terminated, the sequence or timing of cohort decisions, or a detailed statistical analysis plan. The actual dose administered in the later cohorts is not reported in the record presented in the outcome results.

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: Part A was performed on non-Japanese participants and Part B was performed on Japanese participants. Planned doses of MLN3126 800 mg to be decided (TBD) dose for Part A, and MLN3126 300 mg, 800 mg, and TBD dose for Part 2 were not administered due to early termination of the study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety analysis set included all participants who received at least 1 dose of study drug.

5. Baseline Characteristics

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

Population: Baseline analysis set included all participants who were randomized.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Reporting One or More Treatment-emergent Adverse Events (TEAEs), measured over Baseline up to 7 days after last dose of study drug (Day 22).

The primary endpoint counts participants who experienced one or more treatment-emergent adverse events. An event qualifies as treatment-emergent when its onset occurs after the participant receives study drug. The stated assessment period begins at baseline and continues through 7 days after the last dose, identified as Day 22. The safety analysis set includes all participants who received at least 1 dose.

This endpoint is used in safety studies to describe how many participants experienced an adverse event during the specified observation period. Counting each participant once for this measure gives a participant-level summary: someone with one or more events contributes to the count, while the measure does not itself indicate how many total events that participant experienced. It also does not convey event severity, duration, seriousness, or whether an event was judged related to treatment. Those details require separate outcome reporting.

The registry reports one participant with an event among 3 participants in Part A placebo, one among 6 in Part A MLN3126 100 mg, and one among 6 in Part A MLN3126 300 mg. In Part B, it reports no participants with an event among 2 receiving placebo and 2 among 6 receiving MLN3126 100 mg. These are descriptive counts for the listed arms. No inferential comparison or confidence interval for the endpoint is reported in the registry record.

For a small early-phase study, this endpoint can provide a concise account of observed adverse events during a defined period. It cannot, by itself, establish how frequently uncommon events occur in a broader population or whether a difference between groups is more than chance variation.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is binary at the participant level: each participant either did or did not report one or more treatment-emergent adverse events during the specified timeframe. The results are presented as counts alongside the number of participants in each arm. This format preserves the observed number of affected participants and the denominator used for each listed group. The registry does not report percentages, confidence intervals, or a model-based estimate for this endpoint.

What does a count of participants with an event represent?

General statistical explanation: a participant-level event count summarizes whether each person experienced at least one qualifying event. It is different from a count of all events, because a participant who experiences multiple events still contributes only once to the “one or more” participant count. It is also different from a severity scale or an assessment of treatment attribution. The registry defines a treatment-emergent event by its onset after study drug is received, but the primary endpoint does not state that every counted event was caused by study treatment.

The arm results give the observed counts and denominators: Part A placebo, 1 of 3; Part A MLN3126 100 mg, 1 of 6; Part A MLN3126 300 mg, 1 of 6; Part B placebo, 0 of 2; and Part B MLN3126 100 mg, 2 of 6. These are separate arm summaries. The record does not report a pooled estimate across arms or a formal comparison between any active dose and placebo.

Why is uncertainty important?

General statistical explanation: an observed count is subject to sampling variation. A different set of participants from the same underlying population could produce different counts, particularly when groups are small. A confidence interval is a statistical range intended to describe uncertainty around an estimate under a specified method and assumptions. No confidence interval for the primary endpoint is reported in the registry record. Without such an interval or a reported model-based analysis, the degree of uncertainty cannot be expressed from the posted results as a comparative estimate.

General statistical explanation: sparse binary data can make some conventional model-based estimates unstable or impossible to estimate. When one or more groups have no observed events, the data may not support a finite estimate under some methods without additional assumptions or specialized procedures. That issue does not authorize choosing a method after the fact; the registry record does not report which comparative method, if any, was planned.

What can be inferred from the absence of an analysis?

The registry lists zero posted analyses. It also indicates that values are missing or not estimable for a two-arm comparison of the binary endpoint. Accordingly, the primary results are descriptive arm counts rather than an inferential comparison. No p-value, effect estimate, or confidence interval for a treatment-placebo contrast is reported. A reader should not treat the numerical pattern across arms as evidence of a statistically established difference.

The study description includes ascending dose cohorts and matched placebo, but the registry record does not report the decision rules used to advance cohorts, any interim analyses, or an analysis plan. It does not report a sample-size justification or a target number of participants for a particular power or precision goal. A separate planning illustration, if consulted, is not the study’s own design justification and is not observed power. The stated illustration framework uses a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect set as a fraction of the observed effect; the record does not report the trial’s own use of these assumptions.

The secondary outcomes are pharmacokinetic measures for MLN3126 and its metabolite. They include maximum plasma concentration, time to maximum concentration, several area-under-the-curve measures, apparent oral clearance after multiple dosing at steady state, and terminal phase elimination half-life. These outcomes can characterize drug exposure and elimination. General statistical explanation: pharmacokinetic measures are often continuous or time-based quantities, and their analysis can require summaries suited to their distributions. The registry record does not report the numerical results or analysis methods for these secondary outcomes.

The registry lists 20 outcome measures and 16 posted secondary outcomes, but the values for the secondary outcomes are not reported in the registry record. It is therefore not possible to evaluate their distributions, estimate their precision, or compare them across arms from the posted results. No additional quantitative interpretation should be inferred from their titles alone.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Part A: Placebo", "Part A: MLN3126 100 mg", "Part A: MLN3126 300 mg", "Part B: Placebo", "Part B: MLN3126 100 mg")
n      <- c(3, 6, 6, 2, 6)
events <- c(1, 1, 1, 0, 2)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Part A: Placebo  3  1  33.3  0.8  90.6  6.1  79.2  6.8  80.6
ARM  Part A: MLN3126 100 mg  6  1  16.7  0.4  64.1  3.0  56.4  3.7  57.9
ARM  Part A: MLN3126 300 mg  6  1  16.7  0.4  64.1  3.0  56.4  3.7  57.9
ARM  Part B: Placebo  2  0  0.0  0.0  84.2  0.0  65.8  0.8  70.8
ARM  Part B: MLN3126 100 mg  6  2  33.3  4.3  77.7  9.7  70.0  9.9  71.0

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists the primary safety endpoint and multiple secondary outcomes. The secondary outcomes cover pharmacokinetic measures for MLN3126 and its metabolite, including concentration, time-to-peak, exposure over specified intervals, clearance, and terminal half-life. It lists 20 outcome measures overall and 16 posted secondary outcomes. Numerical results for those secondary outcomes are not reported in the registry record.

Multiplicity concerns arise generally when many outcomes or comparisons are assessed: repeated testing can increase the chance of finding an apparently notable result by chance. Whether and how to address this depends on the prespecified analysis plan and the role of each outcome. The registry record does not report a multiplicity adjustment, a hierarchy among secondary outcomes, or a detailed statistical analysis plan. No multiplicity-adjusted result can therefore be described.

The record does not report how missing outcome data were handled, whether any participants were excluded from particular analyses, or how incomplete follow-up was addressed. It does define the primary safety analysis set as participants who received at least 1 dose of study drug. That definition identifies the intended population for the safety endpoint, but does not describe analysis populations for pharmacokinetic, pharmacodynamic, or other outcomes. Those populations are not reported in the registry record.

General statistical context: missing observations can affect an estimate if participants with missing data differ in relevant ways from those whose outcomes are observed. The extent and handling of missing data should therefore be described when interpreting results. The registry outcome results do not give this information. The reported counts are best read as the posted observations for the listed arms, without assuming any unreported imputation or adjustment procedure.

12. 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 non-serious adverse event terms

The serious adverse event results report zero affected participants in every listed arm. The denominators at risk are 3 for Part A placebo, 6 for Part A MLN3126 100 mg, 6 for Part A MLN3126 300 mg, 2 for Part B placebo, and 6 for Part B MLN3126 100 mg. No serious adverse event terms are listed. The registry record does not report death counts in these arm summaries.

These serious-event figures are distinct from the primary endpoint. The primary endpoint counts participants with one or more treatment-emergent adverse events, whether or not those events were serious. The posted primary results include participants with events in four of the five arms, while the serious-event summary reports no serious events in the listed arms. Thus, “no serious adverse events reported” should not be read as “no adverse events.”

General statistical context: zero observed serious events during a study does not demonstrate that the underlying risk is zero. The number of participants and the observation period affect how much can be learned about uncommon events. These figures describe what was recorded for the listed groups during this study; they do not establish the absence of serious events in larger or different populations. The registry record does not report an analysis that quantifies uncertainty around the serious-event counts.

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

The posted primary outcome results describe how many participants in each listed arm reported at least one treatment-emergent adverse event. They show one affected participant in each of the three Part A arms, no affected participants in Part B placebo, and two affected participants in Part B MLN3126 100 mg. The serious adverse event summary reports zero affected participants in each listed arm. These observations apply to the arms and follow-up period recorded in the registry.

They do not establish a causal difference between MLN3126 and placebo. The registry record reports no formal two-arm analysis, no confidence interval, and no p-value for the primary endpoint. The arm counts are descriptive, and the small denominators mean that the observed values provide limited precision. General statistical context: absence of a reported difference test is not evidence that the groups are equivalent, just as a numerical difference in counts is not proof that treatment caused a difference.

The results also do not characterize all doses described in the protocol. The cohort descriptions include an 800 mg dose, but the posted primary outcome arm results list MLN3126 100 mg and 300 mg in Part A and 100 mg in Part B, alongside placebo arms. The registry record does not provide a primary endpoint result for an 800 mg arm. The listed arm results also do not identify a direct Japanese-versus-non-Japanese comparison.

The study’s purpose extended beyond safety to tolerability, pharmacokinetics, and pharmacodynamics. Although several secondary pharmacokinetic outcomes are named, their numerical results are not reported in the registry record. No conclusion about those outcomes can be drawn from their titles or from the adverse event counts. The meaning of the posted data is therefore limited to the recorded descriptive safety observations, rather than a complete assessment of every stated study objective.

The study was terminated, but the reason is not reported in the registry record. Termination status alone does not explain why enrollment stopped or establish that any particular safety or efficacy finding prompted the decision. The posted results should be interpreted without assigning a cause to that status.

14. Why This Trial Matters Statistically

This trial illustrates an important distinction in early-phase clinical research: a study can collect safety observations across dose cohorts without producing a precise comparative estimate. The registry gives participant-level event counts for the listed active-treatment and placebo arms, but no two-arm analysis is reported. Those counts are useful as a descriptive record of what occurred among the participants followed in the study; they do not by themselves resolve whether observed differences reflect treatment, chance variation, or other factors.

The endpoint also shows why the definition and unit of an outcome matter. “One or more” treatment-emergent adverse events counts participants, not the total number of events. It does not report severity or duration, and it is not identical to the serious adverse event measure. Reading the primary outcome and serious-event figures together prevents the zero serious-event counts from being mistaken for an absence of all adverse events.

General statistical context: small groups are particularly sensitive to individual outcomes, and sparse event counts can limit the usefulness of standard comparative methods. This study’s listed arm sizes range from 2 to 6 participants, making it important to distinguish observed counts from precise estimates that generalize beyond the enrolled participants. The registry does not provide confidence intervals to quantify that uncertainty.

The record also makes clear that design labels and outcome availability are different things. The study is described as randomized, masked, placebo-controlled, and sequential-cohort, while the posted results include only a subset of the dose arms described and no numerical secondary outcome results. For clinical researchers, this underscores the importance of checking which outcomes and groups actually have results recorded, rather than assuming that every planned objective has a corresponding posted analysis.

15. 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 outcome results cover only the listed arms: Part A placebo, Part A MLN3126 100 mg, Part A MLN3126 300 mg, Part B placebo, and Part B MLN3126 100 mg. Although the study description includes 800 mg cohorts and later cohorts with doses to be determined, a corresponding primary outcome result for an 800 mg arm is not reported in the registry record. The recorded outcome groups therefore do not represent every cohort described in the study design.

The results use Part A and Part B labels, but the outcome data do not explicitly identify those arms by participant nationality. The study is intended to include healthy Japanese and non-Japanese participants, yet the posted counts do not permit a direct comparison between those populations. The registry also does not report participant-level characteristics that would support further assessment of how representative the enrolled groups were.

The primary outcome is a participant count over a defined period. The registry does not report event severity, event duration, individual event terms for this endpoint, or an assessment of treatment relatedness for the counted events. The separate serious adverse event summary lists no serious-event terms and does not report death counts. These omissions limit the clinical detail available from the safety results.

No inferential comparison, confidence interval, or statistical analysis plan is reported for the primary endpoint. The registry does not describe missing-data handling, interim analyses, the sample-size justification, or the reason for termination. Numerical results for the named pharmacokinetic and other secondary outcomes are also not reported. These limitations prevent a full evaluation of comparative safety, dose response, and the study’s stated pharmacokinetic and pharmacodynamic objectives using the registry record alone.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of MLN3126 in Healthy Japanese and Non-Japanese Participants — NCT02209506.
• Registry record last updated 2016-07-25; status last verified 2016-07.
• Results first posted 2016-07-25.
• 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.

19. Record Summary

NCT02209506 is a randomized, quadruple-masked, parallel-group phase 1 study sponsored by Takeda. It evaluated single and multiple oral doses of MLN3126 and matched placebo in healthy Japanese and non-Japanese participants. The registry lists enrollment of 23, a study start of 2014-07, primary completion of 2014-09, and status as terminated. The reason for termination is not reported in the registry record.

The primary endpoint was the number of participants reporting one or more treatment-emergent adverse events from baseline through 7 days after the last dose, identified as Day 22. The posted results provide counts for three Part A arms and two Part B arms. The registry reports no serious adverse events in those listed arms, but does not report a two-arm analysis or confidence intervals. Numerical results for the listed secondary outcomes are not reported in the registry record.