A Single-dose Phase 1 Study of DBPR108 in Healthy Male Subjects: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Single-dose Phase 1 Study of DBPR108 in Healthy Male Subjects (NCT01650324), a randomized phase 1 study. The primary outcome is Number of Participants With Adverse Events as a Measure of Safety and Tolerability.

2. Clinical Question

This question is narrower than the study’s overall aims. The registry also lists pharmacokinetic outcomes, including area under the plasma concentration-time curve from 0 to infinity, observed maximum plasma concentration, and time of maximum plasma concentration. A pharmacodynamic outcome concerns change in DPP4 activity between 48 Hrs post dose and 0 hr predose. Those outcomes address drug exposure and biological activity; the primary safety outcome instead records participants with adverse events.

The record describes the participants as healthy male subjects, while the listed condition is Diabetes Mellitus, Type 2. It does not report that the enrolled participants had that condition, so the condition listing should not be treated as a description of the study population. Findings from this participant group do not, by themselves, characterize safety or other outcomes in people with diabetes or in populations not represented in the record.

3. Trial Design

This was a randomized Phase 1 study of single oral doses of DBPR108 and matching placebo. The registry reports 32 enrolled participants. The posted arms are placebo, DBPR108 25 mg, DBPR108 100 mg, DBPR108 300 mg, and DBPR108 600 mg. The arm descriptions are blank, so further details about how participants were assigned, dose escalation, or the sequence of study procedures are not reported in the registry record.

The official title describes the study as double-blind, while the registry’s masking description is triple. These are different descriptions of masking, and the record does not explain the difference or identify which study roles were masked. The registry also labels the model as single-group despite listing randomized placebo and dose arms. This internal mismatch limits confidence in interpreting the design metadata; it does not change the fact that multiple arms and their participant counts are posted.

The study’s stated purpose was to assess safety, tolerability, pharmacokinetic properties, and pharmacodynamic properties after single oral doses in healthy male subjects. It is listed as completed. The recorded study start is 2012-07, and primary completion is 2012-12. The primary adverse-event collection period ran from Day -1 (baseline) through the end of the study, up to Day 7.

The record gives no additional account of the randomization process, allocation concealment, dose assignment procedures, or protocol deviations. Details about eligibility criteria beyond the description of healthy male subjects are not reported in the registry record. These gaps matter when considering whether the posted groups can be regarded as comparable and how broadly the results might apply. The available design description supports a basic account of the arms and study purpose, but not a reconstruction of the full conduct of the trial.

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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All enrolled participants.

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: All enrolled participants.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Adverse Events as a Measure of Safety and Tolerability, measured over Adverse events were collected from Day -1 (baseline) through the end of the study, up to Day 7..

The primary endpoint is the number of participants with adverse events, described as a measure of safety and tolerability. It is a count outcome: the record reports participant counts by arm, rather than a continuous measure such as a laboratory value. The stated collection window began at Day -1 (baseline) and continued through the end of the study, up to Day 7. The outcome population is all enrolled participants.

Counting participants with adverse events is one way to describe how many people experienced an event during observation. It can help distinguish a group with no recorded affected participants from a group in which events were recorded. The endpoint does not, by itself, describe event severity, duration, clinical importance, or whether an event was considered related to the study drug. Those details require separate reporting.

The registry describes four mild adverse events during the study. The posted primary outcome gives participant counts by arm, which should not automatically be read as the total number of events: one participant could experience more than one event. The record does not clarify how the four-event description corresponds to the arm-level counts. The endpoint is therefore best read as a descriptive safety count, not as a complete account of all event characteristics.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

For a binary safety outcome, each participant is classified according to whether an adverse event was recorded during the defined observation period. Arm-level results can then be expressed as counts of participants with an event. The posted primary outcome is explicitly a participant count, and the record gives the number of participants in each arm. These counts allow a direct descriptive reading of the observed safety experience, but they do not automatically provide an estimate of the difference between DBPR108 and placebo.

What does a count show?

A count reports how many observed participants met the outcome definition. It does not communicate the uncertainty around that count unless an interval or another uncertainty measure is also reported. For a treatment comparison, an analyst would typically define an effect measure and estimate how the event experience differs between groups. The registry record does not post such an estimate for this endpoint. It also does not post a confidence interval or a test result. General statistical interpretation therefore distinguishes the recorded counts from evidence about a population-level treatment effect.

A confidence interval, in general, describes a range of values compatible with the data under a specified statistical method. Its width conveys precision: a wide interval indicates greater uncertainty, while a narrower interval indicates greater precision. No confidence interval for the primary outcome is reported in the registry record, so the precision of a dose-versus-placebo effect cannot be read directly from the posted result. A count of zero in a small group is not proof that the underlying event probability is zero.

Why is a formal comparison unavailable?

The registry indicates that values are missing or not estimable for a two-arm comparison of this binary endpoint. That is consistent with the absence of a posted comparison estimate or inferential analysis. Without a reported effect estimate and its uncertainty, it would be inappropriate to describe the observed count pattern as a statistically established difference. The registry reports no analyses for the primary outcome. Any recalculation from summary counts would be an unadjusted analysis and would not replace a sponsor’s own analysis; however, no sponsor comparison is posted in the record to take precedence.

General methods for comparing binary outcomes include tests of proportions and regression models for binary responses. The choice depends on the design, estimand, data structure, and assumptions. With several arms, the analysis also needs to specify whether each dose is compared separately with placebo, whether dose is treated as an ordered exposure, or whether another contrast is of interest. The registry does not report which approach was planned or used. No particular test or model should therefore be attributed to this trial.

How should the planning illustrations be understood?

Sample-size calculations are prospective planning tools: they describe the number of participants that might be needed under stated assumptions to detect a target effect with a chosen error rate and power. They do not measure the power achieved by a completed trial. The record describes an illustration based on an observed effect and notes that the binary endpoint does not have values available or estimable for a two-arm comparison. No usable effect-based comparison or participant-per-arm planning value is reported for this endpoint. A sample-size justification for the actual study is not reported in the registry record.

General power calculations depend on assumptions about the effect to detect, event frequency, significance level, allocation, and analysis method. If the observed difference is absent or cannot be estimated, planning from that observed effect may not yield an informative illustration. Any planning figure should be read as conditional on its assumptions, never as observed power or as evidence that a completed study was adequately powered. The registry does not report a protocol-based sample-size rationale, so one cannot infer why the enrolled total or arm sizes were selected.

What does the endpoint definition leave open?

The outcome is the number of participants with adverse events, but the record does not specify how events were coded, whether repeated events in one person were counted once for this endpoint, or how missing observations were handled. In general, these choices affect the meaning of a binary participant-level outcome. The separate description of four mild events does not explain whether those events correspond one-to-one with participants. The registry also does not report an analysis population beyond identifying all enrolled participants for the primary outcome.

These limitations do not prevent a descriptive reading of the posted arm counts. They do limit conclusions about comparative effects, uncertainty, and analytic robustness. The most defensible interpretation stays close to the recorded counts and clearly separates them from unreported inferential methods.

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("Placebo", "DBPR108 25 mg", "DBPR108 100 mg", "DBPR108 300 mg", "DBPR108 600 mg")
n      <- c(8, 6, 6, 6, 6)
events <- c(0, 0, 0, 1, 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  Placebo  8  0  0.0  0.0  36.9  0.0  32.4  0.3  33.6
ARM  DBPR108 25 mg  6  0  0.0  0.0  45.9  0.0  39.0  0.4  41.0
ARM  DBPR108 100 mg  6  0  0.0  0.0  45.9  0.0  39.0  0.4  41.0
ARM  DBPR108 300 mg  6  1  16.7  0.4  64.1  3.0  56.4  3.7  57.9
ARM  DBPR108 600 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 lists four secondary outcomes: area under the plasma concentration-time curve from 0 to infinity, observed maximum plasma concentration, time of maximum plasma concentration, and change in DPP4 activity between 48 Hrs post dose and 0 hr predose. It reports five outcome measures in total. The record does not describe whether these outcomes were designated as confirmatory or exploratory, how multiple comparisons were handled, or whether any adjustment for multiplicity was planned. When several outcomes or dose comparisons are examined, general statistical practice recognizes that the chance of at least one apparently unusual result can increase; whether and how to address that depends on the prespecified analysis plan.

Missing-data methods are not reported in the registry record. The primary outcome population is described as all enrolled participants, but the record does not state whether all enrolled participants contributed data, how incomplete adverse-event follow-up was treated, or how missing outcome information would be classified. It also does not describe exclusions or analysis populations for the secondary outcomes.

The record reports zero posted analyses for the primary outcome and does not give a statistical analysis plan. It does not report interim analyses, stopping rules, or a hierarchy for testing outcomes. These omissions mean that readers cannot determine from the registry record whether the posted safety counts were part of a prespecified inferential framework or how unreported outcomes and missing observations were handled. The counts remain descriptive evidence for the recorded participants and observation period.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The serious-adverse-event fields report zero affected participants in the placebo arm and in each DBPR108 dose arm. The record lists no serious adverse-event terms. This means that the registry’s arm-level serious-event fields contain no recorded serious events; it should not be expanded into a claim about events outside the reported observation period or about outcomes not captured in the record.

The primary outcome is broader than serious adverse events. Its arm-level counts show no participants with adverse events in placebo, DBPR108 25 mg, or DBPR108 100 mg; one in DBPR108 300 mg; and two in DBPR108 600 mg. The study description also says that four mild adverse events were observed. Those mild events are not serious events, and the record does not provide event-level detail that would link each one to a participant or arm.

Death counts are not reported in the registry record. Zero serious events should therefore be interpreted only as the posted serious-event result, not as a complete summary of all safety outcomes. Small groups and limited follow-up also constrain what can be learned about uncommon events. The data describe the recorded experience; they do not establish the absence of risks.

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

The result provides a limited descriptive account of adverse events following single oral doses of DBPR108 or matching placebo in healthy male subjects. The posted participant counts are zero for placebo and for the 25 mg and 100 mg dose groups, one for 300 mg, and two for 600 mg. The registry’s narrative reports four mild adverse events. The serious-event fields report zero serious events in each arm.

These observations do not establish a causal effect of DBPR108 on adverse events. The record does not provide a formal dose-versus-placebo analysis, an estimate of comparative risk, a confidence interval, or a statistical test. The counts alone cannot determine whether the pattern reflects a dose-related effect, random variation, or other factors. The small arm sizes also mean that the observed pattern is imprecise as a basis for describing event frequencies beyond the participants studied.

Nor do the results establish that no safety concerns exist. Zero serious events in the posted fields is not evidence that serious events are impossible, particularly when the study has limited enrollment and follow-up through Day 7. Death counts are not reported in the registry record, and the record provides no detailed event descriptions beyond the statement that four mild events occurred.

The broader study aims included pharmacokinetic and pharmacodynamic assessment, but the listed numerical results for those outcomes are not available in the record details used for this interpretation. The safety counts therefore cannot be related to drug concentrations or changes in DPP4 activity. These findings should be understood as a report of the observed safety data in this particular Phase 1 study, rather than a general conclusion about clinical use or about populations beyond the healthy male subjects enrolled.

14. Why This Trial Matters Statistically

This trial illustrates how registry results can contain useful descriptive safety information without supporting a formal treatment comparison. The outcome is readily interpretable as a count of participants with adverse events, and the arms make the observed pattern visible across placebo and four DBPR108 dose levels. At the same time, the lack of a posted effect estimate, uncertainty interval, or analysis means that the counts should not be mistaken for a quantified difference between groups.

It also shows why endpoint terminology matters. The primary outcome counts participants with adverse events, whereas the narrative describes four mild adverse events. Events and affected participants are not necessarily the same unit: a participant may experience more than one event. Because the registry does not reconcile these descriptions, careful interpretation requires preserving that distinction rather than silently treating the figures as equivalent.

Several metadata inconsistencies further illustrate the need to read registry descriptions critically. The official title calls the study double-blind, the masking description says triple, and the model is labeled single-group despite the posted placebo and dose arms. These differences do not reveal what happened operationally, but they make the design less straightforward to reconstruct from the record alone.

Finally, the study’s small groups and short stated observation window matter for interpreting safety counts. They define what the record can describe and constrain conclusions about uncommon events or longer-term outcomes. Together, these features make this trial a useful example of the distinction between observed data, an inferential analysis, and the broader claims that an analysis might support.

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 registry record offers only limited detail about the conduct and analysis of this trial. It does not report the randomization procedure, allocation concealment, the roles included in masking, or an explanation for the difference between the double-blind official title and triple masking description. The single-group model label is also difficult to reconcile with the listed placebo and dose arms. These inconsistencies leave important design details unresolved.

The posted primary safety outcome is descriptive. There is no reported comparison estimate, confidence interval, or test result, and the record lists no analyses for this outcome. The sample-size rationale and statistical analysis plan are not reported in the registry record. Consequently, readers cannot assess a prespecified target effect, planned power, analysis choices, or the intended handling of multiple dose comparisons.

Outcome detail is limited. The record reports four mild adverse events, but does not state how those events relate to the participant counts by arm. It provides no serious-event terms and does not report death counts. Details such as event timing, duration, relatedness, and resolution are not reported in the registry record. Missing-data handling, protocol deviations, and analysis populations beyond the stated all-enrolled primary population are also not described.

Generalizability is constrained by the study description: it concerns healthy male subjects, uses single oral doses, and collects adverse events through Day 7. The record does not provide numerical results for the listed pharmacokinetic and pharmacodynamic outcomes in the information available for this interpretation. These limitations mean that the posted counts should be treated as a narrow account of recorded events in this study, not as a complete safety profile or as a basis for conclusions about other populations, dosing patterns, or longer follow-up.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Single-dose Phase 1 Study of DBPR108 in Healthy Male Subjects — NCT01650324.
• Registry record last updated 2014-08-28; status last verified 2014-02.
• Results first posted 2014-08-28.
• 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

The registry describes a completed randomized Phase 1 study of single oral doses of DBPR108 and matching placebo in healthy male subjects. It reports 32 participants enrolled, with placebo and DBPR108 dose arms at 25 mg, 100 mg, 300 mg, and 600 mg. Adverse events were collected from Day -1 (baseline) through the end of the study, up to Day 7.

The primary outcome counts participants with adverse events. The posted counts are zero in placebo and the 25 mg and 100 mg arms, one in the 300 mg arm, and two in the 600 mg arm. The narrative reports four mild adverse events. The arm-level serious-event fields report zero serious events; death counts are not reported in the registry record.

No primary-outcome analyses or formal treatment comparisons are posted. The registry also lists four secondary pharmacokinetic and pharmacodynamic outcomes, but their numerical results are not reported in the record details used. The design descriptions and statistical plan have unresolved gaps, so the results support a descriptive reading rather than a precise comparative conclusion.