Safety and Efficacy Study of Adjunctive Antiplatelet Therapy Prior to Primary PCI in Patients With STEMI: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy Study of Adjunctive Antiplatelet Therapy Prior to Primary PCI in Patients With STEMI (NCT00546260), a randomized phase 2 study. The primary outcome is Number of Patients With Thrombolysis in Myocardial Infarction (TIMI) Major/Minor Bleeding, Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) Severe/Moderate Bleeding Through Hospital Discharge, and Intracranial Hemorrhage Through 30 Days.

2. Clinical Question

3. Trial Design

The registry describes a randomized, triple-masked, parallel-group Phase 2 study of adjunctive antiplatelet therapy before primary PCI in patients with STEMI. Its title identifies intravenous PRT060128 as the experimental treatment. Placebo was used as a comparator, and the arm descriptions identify placebo and experimental-drug cohorts at 10, 20, 40, and 60 mg. The record does not state how participants were distributed among the dose cohorts, how randomization was implemented, or which roles were masked.

Enrollment is recorded as 70. The listed start date is 2007-11 and the primary completion date is 2008-07. The study status is terminated. The reason for termination is not reported in the registry record, and the status alone does not establish why the trial ended or what its termination means for interpretation of results.

The primary outcome concerns bleeding events over different periods: specified TIMI and GUSTO bleeding categories through hospital discharge, and intracranial hemorrhage through 30 days. The secondary outcomes are corrected TIMI Frame Count in the infarct artery on the initial diagnostic angiogram before primary PCI and percentage ST-segment resolution prior to PCI. Although the record lists three outcome measures, it does not provide results for the secondary outcomes in the information available for this analysis.

The primary-outcome population is described as an as-treated population comprising subjects who received some component of study drug. The record does not report a corresponding intention-to-treat analysis or describe how participants with incomplete outcome data were handled. It lists 0 analyses. This means no analysis results are listed in the registry record; it does not, by itself, show what analyses may have been performed outside the record.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All subjects receiving some component of study drug (the "as-treated" population)

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 Patients With Thrombolysis in Myocardial Infarction (TIMI) Major/Minor Bleeding, Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) Severe/Moderate Bleeding Through Hospital Discharge, and Intracranial Hemorrhage Through 30 Days, measured over 30 days.

The primary endpoint counts participants with specified bleeding events: TIMI major or minor bleeding, GUSTO severe or moderate bleeding through hospital discharge, and intracranial hemorrhage through 30 days. The registry’s definitions distinguish event severity using clinical consequences and laboratory changes. TIMI major bleeding includes intracranial bleeding, a decrease in hemoglobin concentration of 5g/dL or more, or a decrease in hematocrit of 15% or greater. TIMI minor bleeding is defined by a hemoglobin decrease of 3g/dL but <5g/dL, or a hematocrit decrease of 10-15%. GUSTO severe or life-threatening bleeding includes intracranial hemorrhage or bleeding causing hemodynamic compromise that requires intervention. GUSTO moderate bleeding requires blood transfusion without hemodynamic compromise requiring intervention.

In general, a safety endpoint of this kind is used to monitor clinically important bleeding while evaluating an antiplatelet treatment. Combining named event categories can capture more than one form or severity of bleeding, but the interpretation depends on knowing how events were counted and whether participants could meet more than one criterion. The registry record does not explain whether overlapping categories were counted once or separately. Its description also defines stroke as a new focal neurologic deficit that does not resolve within 24 hours, but does not clarify how that definition relates to the endpoint title.

The endpoint spans different observation periods, with the TIMI and GUSTO categories specified through hospital discharge and intracranial hemorrhage through 30 days. No participant counts or treatment comparison for the primary endpoint are reported, so the frequency of the endpoint and the precision of any treatment contrast cannot be assessed from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Randomization is a design method that assigns participants to treatment groups by chance. In general, random allocation helps make groups comparable with respect to both measured and unmeasured characteristics, though it does not guarantee identical groups, especially in a small study. The registry identifies this trial as randomized but does not describe the sequence-generation method, allocation concealment, or the number assigned to each arm or dose cohort. Those details are not reported in the registry record.

Triple masking means the registry classifies the study as masked at three levels, but it does not specify which people or roles those levels represent. Masking is intended in general to reduce the influence of treatment knowledge on care, outcome assessment, and analysis. The record does not describe how masking was maintained or whether it was broken for any participant.

What does the primary outcome count?

The primary outcome is a count of participants meeting named bleeding criteria, rather than a continuous measurement such as a laboratory value. The title combines TIMI major and minor bleeding, GUSTO severe and moderate bleeding through hospital discharge, and intracranial hemorrhage through 30 days. The individual definitions give clinical and laboratory thresholds. A count-based outcome can be summarized as the number of participants with an event, but interpretation also requires clarity about the event rules, observation period, and handling of participants who meet more than one criterion. The registry does not explain whether those categories are mutually exclusive or how repeated events were treated.

Outcome definitions matter because different severity criteria capture different clinical experiences. For example, the listed TIMI definitions use hemoglobin and hematocrit changes as well as intracranial bleeding; the GUSTO definitions refer to hemodynamic compromise and transfusion. The record’s endpoint description also defines stroke, but does not explain its relationship to the endpoint title. Without a reported endpoint count and explicit counting rules, the exact construction of a single composite result cannot be reconstructed from the registry description.

What do estimates and confidence intervals tell readers?

In general, an effect estimate expresses the observed contrast between groups on a defined outcome. A confidence interval gives information about the precision of that estimate and the range of values reasonably compatible with the data under the statistical model. A narrow interval indicates greater precision than a wide interval, while neither an estimate nor its interval establishes causation independently of the design and analysis. No primary-outcome estimate or interval is reported in the registry record, so neither the size nor the precision of a primary comparison can be assessed.

A p-value, when reported, describes how compatible observed data are with a specified null hypothesis under the assumptions of a statistical test. It does not measure the probability that a treatment is effective, nor does it describe the magnitude of an effect. No primary-outcome p-value is listed. The absence of an analysis result means there is no reported inferential statistic to interpret for that endpoint.

How should the planning assumptions be understood?

The record’s sample-size assumptions describe a planning illustration based on the observed effect, not the trial’s own design. They specify a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For non-time-to-event outcomes, the stated planning convention is participants per arm for 80% power or another listed power target. Such calculations are conditional illustrations: they depend on the effect and assumptions used and do not report the trial’s observed power. No sample-size justification for the original trial is reported in the registry record, and no numerical planning result is stated in the information available for this analysis.

In general, over-dispersion matters when outcome variability is greater than a model assumes. If ignored, standard errors can be too small and confidence intervals too narrow. The registry record does not report a model-based primary-outcome analysis or an over-dispersion assessment, so there is no basis to say whether either was relevant to the reported analysis. The primary endpoint is a participant count, and its analysis would require a clear definition of the event and comparison, but the record does not specify the statistical model.

What analysis details are missing?

The registry lists 0 analyses and does not report a test, model, adjustment strategy, or treatment-effect estimate for the primary outcome. It also does not report whether the trial used interim analyses, how any interim findings were handled, or whether a statistical plan specified in advance how the multiple dose cohorts and outcomes would be evaluated. Those design and analysis details are not reported in the registry record. As a result, readers cannot verify the analysis population, model assumptions, or inferential procedures from the posted record.

10. Multiplicity, Missing Data and Analysis Populations

The study includes experimental and placebo cohorts at 10, 20, 40, and 60 mg, as well as a primary safety outcome and secondary outcomes involving corrected TIMI Frame Count and ST-segment resolution. Considering multiple doses, outcomes, event categories, or time points can create multiplicity: the more comparisons examined, the greater the chance that some results appear notable by chance. In general, prespecified comparisons and suitable multiplicity procedures can help control this issue. The registry record does not report a multiplicity strategy, a hierarchy among outcomes, or which dose comparisons were planned for formal testing.

The primary outcome itself combines several bleeding categories and time windows. The record notes that it is not reduced to one comparison, and it does not report separate results for the listed categories. It is therefore not possible to determine whether any particular component drove an overall result or how repeated or overlapping events were counted.

The primary-outcome population is the as-treated population, defined as all subjects receiving some component of study drug. An intention-to-treat analysis, which generally compares participants according to randomized assignment, is not reported. The registry also does not describe missing outcome data, withdrawals, exclusions, or methods used to address missingness. These details are not reported in the registry record, so the potential influence of missing data and departures from assigned treatment cannot be evaluated.

The record lists 0 analyses. It does not report an interim-analysis plan, stopping criteria, or a statistical analysis plan. The terminated status does not establish whether an interim review occurred or why the trial ended. These omissions limit assessment of multiplicity, analysis choices, and the completeness of outcome reporting.

11. 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: cardiogenic shock (5.6%), chest pain (5.6%), thrombosis in device (2.9%), ischaemic stroke (2.9%), angina unstable (2.8%).

The adverse-event listings separate serious adverse events from other adverse events. In the placebo group, 8 of 36 at-risk participants are listed as affected by serious events, and 15 of 36 are listed as affected by other events. In the experimental group, 2 of 34 at-risk participants are listed as affected by serious events, and 21 of 34 are listed as affected by other events. These are descriptive counts from the registry record, not adjusted estimates or formal comparisons.

The record lists cardiogenic shock and chest pain at 5.6% each among the top serious terms, thrombosis in device and ischaemic stroke at 2.9% each, and angina unstable and vessel puncture site haemorrhage at 2.8% each. The registry does not provide the event-level counts, group-specific breakdowns, or additional denominators for these terms in the information available for this analysis. The percentages should therefore be read as reported, without inferring a group-specific risk or treatment effect.

These adverse-event listings are not equivalent to the primary bleeding endpoint. The primary endpoint uses specified TIMI and GUSTO bleeding definitions and a separate intracranial-hemorrhage time window; the adverse-event list does not identify which listed events met those criteria. In general, safety counts are easier to interpret when event definitions, exposure, follow-up, and handling of multiple events are clear. Those details are not fully reported in the registry record, and the counts alone do not establish whether treatment caused an event or changed its risk.

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

The record establishes that this was a randomized, triple-masked, parallel-group Phase 2 study of intravenous PRT060128 before primary PCI in patients with STEMI, with placebo comparison and dose cohorts of 10, 20, 40, and 60 mg. It also identifies a primary bleeding-safety outcome and two secondary outcomes. These design details help define the clinical and statistical questions that the trial was intended to address.

The posted information does not report a primary-outcome result or a treatment-effect estimate. It therefore does not show the magnitude or precision of a treatment-placebo contrast for the specified bleeding outcome. The descriptive adverse-event counts are not a substitute for that missing analysis and do not establish a causal effect. No result for corrected TIMI Frame Count or percentage ST-segment resolution is reported in the information available for this analysis.

In general, a randomized design can support a causal comparison when the analysis follows the design, outcome definitions are clear, and missingness and protocol deviations are appropriately handled. Here, the primary population is described as as-treated, while an intention-to-treat result and details of treatment receipt are not reported. The registry also does not describe a statistical plan, multiplicity handling, or the reason for termination. These omissions make it difficult to assess how the intended comparison was analyzed.

The terminated status should be interpreted as a registry status, not as an explanation of the evidence. The reason for termination is not reported in the registry record. Similarly, enrollment of 70 describes the recorded enrollment, but does not by itself establish whether the planned enrollment was reached or whether the study had adequate precision for its intended questions. The original sample-size justification is not reported.

Overall, the registry record supports a description of the trial design, its endpoints, and listed adverse-event counts. It does not support a quantitative conclusion about the primary endpoint, and it does not establish that the experimental treatment did or did not alter bleeding or other outcomes.

13. Why This Trial Matters Statistically

This trial raises several useful statistical issues in a compact clinical setting. First, the primary outcome combines named bleeding categories and more than one observation period. A clear endpoint definition is essential because different criteria can capture different events, and a composite count may be difficult to interpret if overlap and counting rules are unspecified. The registry identifies the components but does not provide one primary comparison or separate component results.

Second, the dose-cohort structure creates multiple potential comparisons. The record describes placebo and experimental cohorts at 10, 20, 40, and 60 mg, alongside secondary measures of coronary flow and ST-segment resolution. In general, evaluating several doses and outcomes raises questions about prespecification and multiplicity. The registry record does not report how these comparisons were prioritized or adjusted.

Third, the stated primary analysis population is as-treated. That choice is relevant because a comparison based on treatment received may not preserve all the advantages of randomization. The record does not provide an intention-to-treat result or enough detail to evaluate the consequences of treatment deviations or missing outcome data.

Finally, the record lists adverse-event counts but no primary treatment-effect estimate, confidence interval, or test result. This illustrates why raw counts and safety listings cannot stand in for a defined inferential analysis. The trial’s terminated status and absence of analysis results also emphasize the distinction between a registered design and an interpretable estimate of effect. For readers, the central statistical lesson is to separate what the registry documents about design and event counts from what can be concluded about comparative outcomes.

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 primary-outcome result is not reported as a single comparison, and the record supplies no event counts, effect estimate, confidence interval, or test result for that endpoint. The outcome spans TIMI and GUSTO bleeding categories through hospital discharge and intracranial hemorrhage through 30 days. The registry does not explain how overlapping criteria, recurrent events, or the stroke definition in the description relate to the primary endpoint.

The record describes an as-treated primary-outcome population but does not report the number assigned to each arm, treatment receipt by randomized group, or an intention-to-treat analysis. Missing outcomes, withdrawals, exclusions, and their handling are not reported. These gaps prevent assessment of whether the analyzed groups correspond to randomized assignment and whether incomplete follow-up could affect the findings.

Although the study is identified as randomized and triple-masked, allocation procedures and the roles covered by masking are not reported. The registry does not provide a statistical analysis plan, model, multiplicity procedure, interim-analysis information, or original sample-size justification. It lists 0 analyses. The reason for the terminated status is not reported, so the status cannot be connected to a particular outcome or decision.

The adverse-event counts are descriptive and do not identify which events satisfy the primary bleeding definitions. Group-specific details for the listed serious terms are not reported in the information available for this analysis. The recorded enrollment of 70 does not by itself indicate the precision of any comparison, particularly because no primary estimate or interval is available. Together, these limitations restrict interpretation to the trial’s documented design and descriptive event listings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety and Efficacy Study of Adjunctive Antiplatelet Therapy Prior to Primary PCI in Patients With STEMI — NCT00546260.
• Registry record last updated 2026-06-24; status last verified 2026-06.
• Results first posted 2011-01-25.
• 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.

18. Record Summary

The registry describes a randomized, triple-masked, parallel-group Phase 2 trial of intravenous PRT060128 before primary PCI in patients with STEMI. Placebo and experimental-drug cohorts are listed at 10, 20, 40, and 60 mg. Enrollment is recorded as 70; the listed start and primary completion dates are 2007-11 and 2008-07, and the study status is terminated.

The primary outcome concerns TIMI major or minor bleeding, GUSTO severe or moderate bleeding through hospital discharge, and intracranial hemorrhage through 30 days. The primary population is described as as-treated. Secondary outcomes are corrected TIMI Frame Count in the infarct artery before PCI and percentage ST-segment resolution prior to PCI.

The record lists serious and other adverse-event counts by group, but does not report a single primary-outcome comparison or analysis result. The reason for termination, missing-data handling, statistical analysis plan, and original sample-size justification are not reported in the registry record.