Study to Evaluate Safety, Tolerability, Pharmacokinetics & Pharmacodynamics of JTT-662 in Subjects With Type 2 Diabetes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Evaluate Safety, Tolerability, Pharmacokinetics & Pharmacodynamics of JTT-662 in Subjects With Type 2 Diabetes (NCT04465877), a randomized phase 1 study. The primary outcome is Number of Subjects With Treatment-emergent Adverse Events.

2. Clinical Question

This is a safety-focused Phase 1 study, not a registry record that establishes a clinical benefit question. The listed primary endpoint counts participants with treatment-emergent adverse events. Its definition starts at or after the placebo dosing on Day -1, so the window includes the placebo run-in period as well as the subsequent treatment and follow-up period. The study title and summary describe JTT-662 administration for 28 days in participants with type 2 diabetes who were receiving metformin monotherapy.

The registry lists four outcome measures and nine analyses, but the registry entries identify only the primary safety endpoint and the adverse-event counts. The other outcome definitions and their results are not reported in the registry record. The endpoint therefore frames a question about observed safety events over the stated period; it does not, on its own, answer questions about efficacy, long-term safety, or how the drug compares across all clinically relevant outcomes.

3. Trial Design

The registry describes a randomized, single-blind, parallel-group, placebo-controlled Phase 1 study. The official title identifies multiple dosing over 28 days, and the brief summary says JTT-662 was administered once daily to participants with type 2 diabetes mellitus receiving metformin monotherapy. Enrollment was 37. The study status is completed; the registry lists a start date of 2020-06-15 and a primary completion date of 2021-02-17.

There were three JTT-662 dose groups and a placebo group. Participants in the 5 mg, 10 mg, and 20 mg groups took the assigned dose orally once daily from Day 1 through Day 28, after a single placebo dose on Day -1. The placebo group took placebo orally once daily from Day -1 through Day 28. The adverse-event table lists 9 participants at risk in each of the 5 mg, 10 mg, and placebo groups, and 10 in the 20 mg group. These are the group sizes in that table; the registry entries do not provide further detail about allocation procedures.

The primary endpoint’s timeframe is six weeks, from Day -1 to the follow-up visit on Day 42. The safety population consists of participants who were randomly assigned and received at least one dose of study drug. “Single-blind” is the masking description in the record, but which study participants or personnel were masked is not reported in the registry record. Details such as the randomization sequence, allocation concealment, site structure, and the reasons for the planned dose groups are also not reported in the registry record. These gaps limit how fully the design can be assessed from the record alone.

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: Following informed consent signing, screening procedures to confirm eligibility were performed. All subjects received a single dose of placebo on Day -1 (Placebo Run-in Period) followed by JTT-662 or placebo once-daily (QD) for 28 consecutive days (Day 1 through Day 28).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety Population consists of subjects who were randomly assigned to treatment and who received at least one 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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Subjects With Treatment-emergent Adverse Events, measured over 6 Weeks (from Day -1 to the follow-up visit on Day 42).

The primary endpoint is the number of participants with treatment-emergent adverse events. An event is defined as any untoward medical experience, whether or not it is related to study drug, with an onset date or time at or after the placebo dose on Day -1. The stated observation window runs from Day -1 to the follow-up visit on Day 42.

This endpoint is used to describe the occurrence of adverse events during a defined period of exposure and follow-up. Counting participants with at least one event gives a participant-level summary: it indicates how many people had an event, rather than how many separate event episodes occurred. The definition’s inclusion of events regardless of a judged relationship to study drug also means that this is a broad safety measure, not a count limited to events considered drug-related.

The timing matters for interpretation. Because the endpoint begins with placebo dosing on Day -1, it covers a period before the JTT-662 dosing described for the active groups, as well as the following treatment and follow-up. The registry reports the adverse-event assessment timeframe, but the registry entries do not specify the analysis method used to derive the primary endpoint or how the run-in period was handled in the primary analysis. The endpoint is a useful descriptive safety measure, but it does not establish causation. A count alone also does not describe event severity, duration, recurrence, or clinical importance; those details are not reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The posted results include adverse-event counts by group, and the surrounding calculated tables and plots should be read as displays of those recorded data. The registry entries identify a participant-count endpoint and its observation period, but do not identify a statistical model or a formal comparison for the primary outcome. The methods discussion below separates what the registry says from general statistical context.

What does a participant count represent?

The endpoint is the number of participants with at least one treatment-emergent adverse event. This is different from counting every event episode. If one person experienced multiple events, a participant-level count would still count that person once for this endpoint. The table separately reports participants affected by serious events and by other events. In the posted breakdown, serious-event counts are zero across the listed groups; the other-event counts are 4, 7, 10, and 6 for the 5 mg, 10 mg, 20 mg, and placebo groups, respectively. The corresponding at-risk counts are 9, 9, 10, and 9.

As general statistical context, a count of participants with an event is often interpreted alongside the number of participants observed in the group. The count alone does not convey the precision of an estimate or account for possible differences in follow-up. The registry entries do not report a confidence interval or a formal inferential analysis for this endpoint. Therefore, comparisons of the listed counts should remain descriptive.

What does a confidence interval add?

As general statistical context, a confidence interval represents uncertainty around an estimate under the assumptions of the method used to construct it. A narrow interval indicates greater precision than a wide interval, while an interval that covers a broad range of possible values leaves substantial uncertainty. No confidence interval for the primary adverse-event comparison is reported in the registry record details. A reader should not infer precision from the point counts alone, and no interval should be reconstructed without the specified analysis and its assumptions.

What does the registry say about the analysis plan?

The record defines the safety population as participants randomly assigned to treatment who received at least one dose. It also identifies the primary endpoint’s timeframe and event definition. The statistical analysis plan, including any model, adjustment, treatment contrast, handling of repeated events, and missing-data procedure, is not reported in the registry record. The method used to decide whether an event was treatment-emergent beyond the timing definition is also not described in the registry record.

As general statistical context, analysis populations matter because a result applies to the people included under the stated rules. A safety population restricted to participants who received at least one dose is not necessarily identical to all participants enrolled or assigned. The registry entries do not provide a flow of participants through assignment, dosing, and follow-up, so any exclusions or missing observations cannot be evaluated.

How should the sample-size illustration be understood?

The registry entries describe a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration’s effect to detect is defined as a stated fraction of the observed effect. Any sample sizes shown in the sample-size section are planning illustrations, not observed trial findings and not evidence of the study’s power. The sample-size assumptions are explicitly not the trial’s own design. No actual illustration values are included in the registry record, so this explanation does not state a participant requirement.

As general statistical context, an illustration based on an observed effect is conditional on that effect and the selected assumptions. It is not a retrospective measure of whether a study was adequately powered, and it cannot substitute for a prespecified design rationale. The study’s sample-size justification and any power calculation are not reported in the registry record. The registry entries also do not report whether interim analyses were planned or performed.

Why can over-dispersion matter?

As general statistical context, over-dispersion describes variability greater than a statistical model expects. If a count model assumes less variability than the data contain, standard errors can be too small and uncertainty can appear understated. This concept is relevant to some analyses of event counts, but the registry entries do not state that an over-dispersion model was used or that over-dispersion was assessed in this trial. The endpoint is framed as a count of participants with an event, and the analysis method is not reported in the registry record.

Overall, the posted information supports a clear descriptive account of the listed safety counts and the endpoint’s time window. It does not support reconstructing a formal treatment-effect estimate, its precision, or the analysis choices behind it. Those questions require statistical details that are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry entries list four outcome measures and nine analyses, but identify only the primary endpoint by name and provide the adverse-event counts. The other outcome definitions and results are not reported in the registry record. The registry entries do not describe whether statistical testing was planned across multiple outcomes, dose groups, or time points, or whether any adjustment for multiple comparisons was used. The number of listed analyses alone does not establish that formal hypothesis tests were conducted.

Multiplicity matters as general statistical context because repeated testing across outcomes or comparisons can increase the chance of a nominally unusual result. Adjustments and prespecified testing strategies can address that issue, but neither the strategy nor any formal testing details are reported in the registry record. The posted event counts should therefore not be presented as results from a documented multiplicity-controlled comparison.

The defined safety population includes participants who were randomly assigned and received at least one dose of study drug. The adverse-event table gives participants at risk for each listed group, but the registry entries do not provide participant-level follow-up completeness, reasons for missing data, or a missing-data handling rule. It is not reported in the registry record whether anyone had an incomplete observation period or how such cases would have been treated in the primary analysis.

The registry entries also do not specify an intention-to-treat analysis population, a per-protocol population, or how deviations from treatment were handled. Details about interim analyses and a formal statistical analysis plan are not reported in the registry record. These omissions do not change the descriptive counts, but they limit assessment of how the results were selected, analyzed, and compared.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse-event rows report zero affected participants in the JTT-662 5 mg, 10 mg, and 20 mg groups and in the placebo group. The at-risk counts are 9, 9, 10, and 9, respectively. The table also lists zero serious events for the placebo run-in group, which had 37 participants at risk. These are the posted counts; the registry entries do not provide details about individual events or their clinical course.

Serious adverse events are distinct from the table’s other adverse-event category. The other-event counts were 4, 7, 10, and 6 in the 5 mg, 10 mg, 20 mg, and placebo groups, and 3 in the placebo run-in group. A zero count for serious events does not mean that no adverse events occurred: other events were recorded in each listed group.

As general statistical context, a zero observed count is not proof that an event cannot occur. Interpretation depends on the number observed, the duration of observation, and the event definition. Here, the primary endpoint timeframe is from Day -1 through Day 42. The registry entries do not provide confidence intervals, event descriptions, or a formal between-group analysis for serious events. The counts should therefore be read as descriptive results within this study, not as a guarantee about risk beyond the observed participants and period.

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

The registry record describes a Phase 1 study of JTT-662 in participants with type 2 diabetes who were receiving metformin monotherapy. It reports a treatment-emergent adverse-event endpoint covering the period from the placebo dose on Day -1 through the follow-up visit on Day 42. The adverse-event breakdown records zero serious adverse events in the active-treatment and placebo groups, while other adverse events affected participants in every group. Those observations summarize what was recorded during the study’s stated window.

They do not show that JTT-662 caused or prevented any particular event. The endpoint definition includes events whether or not they were considered related to study drug. The record details do not provide event names, severity details for the other-event category, formal comparative estimates, or confidence intervals. Without those details, the counts cannot establish the size or precision of a treatment difference, or distinguish drug effects from other explanations for events.

The small group counts also call for restraint in drawing broad conclusions. The table’s 9 or 10 participants at risk in each randomized group describe the data available for this safety summary, not a large body of evidence about uncommon or delayed outcomes. The study’s follow-up period is specified through Day 42; the registry entries do not establish what might happen outside that interval. No result should be extended to populations, treatment settings, or periods that the registry record does not describe.

These results also do not answer an efficacy question. The focus is the posted safety endpoint, and the registry entries do not include results for the other listed outcomes. The appropriate reading is bounded: these are descriptive adverse-event counts from this trial, with important limits on causal, comparative, and longer-term interpretation.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of how a safety endpoint must be read in the context of its definition, observation period, and analysis population. The primary measure counts participants with events rather than event episodes, and includes untoward medical experiences regardless of whether they were considered related to study drug. Its window begins with placebo dosing on Day -1 and continues through the follow-up visit on Day 42. These details shape what the endpoint represents.

The parallel randomized design places three JTT-662 dose groups alongside a placebo group, but the posted group counts remain modest: 9 participants at risk in the 5 mg group, 9 in the 10 mg group, 10 in the 20 mg group, and 9 in the placebo group. As general statistical context, limited group sizes can make event-count comparisons imprecise, particularly when the endpoint is based on whether a participant experienced an event. The registry entries do not report precision estimates or a formal comparison, so descriptive counts should not be mistaken for a definitive ranking of groups.

The record also illustrates the difference between trial results and planning illustrations. The sample-size section may show planning calculations based on the observed effect and stated assumptions, but such calculations are not observed power and are not the study’s own design justification. The sample-size rationale is not reported in the registry record.

Finally, the separate placebo run-in category makes clear why group labels and timing deserve attention. Its counts are not interchangeable with the randomized placebo group. A careful statistical reading preserves those distinctions and states what the record does and does not support, rather than extending the findings beyond the endpoint and period reported.

14. 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 entries offer a limited view of the study’s safety results. They identify the primary endpoint, timeframe, safety population definition, and counts by group, but do not include participant-level data or event descriptions. The table does not show when individual events occurred, how long they lasted, whether they recurred, or how the events in the other category were graded. These details would be needed for a fuller characterization of the safety profile.

The registry entries do not report a confidence interval, p-value, effect estimate, or formal statistical comparison for the primary endpoint. The sample-size assumptions describe an illustration rather than the study’s own design, and no illustration results are included. The sample-size justification and statistical analysis plan are not reported in the registry record. Therefore, readers cannot assess the planned precision, the prespecification of comparisons, or how any analysis decisions were made.

The relationship between the placebo run-in category and the primary endpoint’s full observation window is not explained in the registry record. The run-in row lists 37 participants at risk, while the randomized placebo group lists 9. The counts should be kept separate; the record does not provide enough detail to determine how the run-in information was incorporated into the endpoint analysis.

The registry entries do not report missing-data handling, participant disposition by group, protocol deviations, or the identities of those masked under the single-blind design. They also do not include detailed results for the other listed outcome measures. These limits mean the available data support a description of recorded counts, but not a complete evaluation of analysis conduct, comparative precision, or outcomes beyond the reported safety information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study to Evaluate Safety, Tolerability, Pharmacokinetics & Pharmacodynamics of JTT-662 in Subjects With Type 2 Diabetes — NCT04465877.
• Registry record last updated 2023-01-27; status last verified 2022-04.
• Results first posted 2023-01-27.
• 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.

18. Record Summary

This completed Phase 1 study evaluated JTT-662 in participants with type 2 diabetes mellitus receiving metformin monotherapy. The registry describes it as randomized, single-blind, parallel-group, and placebo-controlled, with enrollment of 37. Participants in the active groups received 5 mg, 10 mg, or 20 mg orally once daily from Day 1 to Day 28 after a placebo dose on Day -1; the placebo group received placebo once daily from Day -1 to Day 28.

The primary endpoint was the number of participants with treatment-emergent adverse events over six weeks, from Day -1 through the follow-up visit on Day 42. The posted breakdown lists zero serious adverse events in the randomized groups. Other adverse events affected 4 of 9 participants in the 5 mg group, 7 of 9 in the 10 mg group, 10 of 10 in the 20 mg group, and 6 of 9 in the placebo group. A separate placebo run-in row lists 3 of 37 participants with other adverse events and zero with serious events.

The counts are descriptive. Formal comparative estimates, precision measures, missing-data methods, and the statistical analysis plan are not reported in the registry record details.