This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Research Study To Assess The Effectiveness And Safety Of Different Doses Of Oral PF-00489791 In The Treatment Of Adult Patients With Pulmonary Arterial Hypertension (NCT00853112), a randomized phase 2 study. The primary outcome is Mean Change From Baseline in Pulmonary Vascular Resistance Index (PVRI) Over 4 Hours Post Dose.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00853112 |
| Phase | Phase 2 |
| Condition | Hypertension, Pulmonary |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 48 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Adults with pulmonary arterial hypertension were the intended population. The official title specifies idiopathic and familial pulmonary arterial hypertension. The registry record does not report detailed eligibility criteria or participant characteristics by arm.
Intervention
Oral PF-00489791 was studied at 1 mg, 2 mg, 4 mg, 10 mg, and 20 mg. The registry record describes the study as investigating dose response and acute hemodynamics.
Comparator
Placebo is identified as a comparator. Sildenafil was also included as an observational comparator arm; its role differs from the placebo comparison, and the registry record does not describe further details of that arm.
Primary question
The primary endpoint was mean change from baseline in pulmonary vascular resistance index (PVRI) over 4 hours post dose on Day 1. The registry record does not report the numerical results needed to describe the size or precision of the observed changes or comparisons.
The clinical question is therefore about short-term changes in a hemodynamic measure after dosing, rather than a long-term clinical outcome. The study also listed multiple secondary hemodynamic outcomes, including measures of systemic vascular resistance, cardiac index, and pulmonary artery pressures. Those outcomes provide context about what investigators planned to assess, but their inclusion does not establish that results were reported or that any particular change occurred.
The registry record lists an enrollment of 48. That is the recorded study enrollment, not a statement about how many participants contributed data to every outcome. The primary-outcome description specifies that the overall analyzed number was the number evaluable for the measure, while the number analyzed at individual time points could vary. Counts contributing to each primary comparison are not reported in the registry record.
3. Trial Design
This was a phase 2a randomized, triple-masked, parallel-group study. Its official title describes a double-blind, placebo-controlled study of dose response in acute hemodynamics; the registry fields separately identify triple masking. The record does not specify which people or roles were masked, how masking was maintained, or how the randomization sequence was generated or concealed.
The planned PF-00489791 dose groups were 1 mg, 2 mg, 4 mg, 10 mg, and 20 mg, alongside placebo. Sildenafil was included as an observational comparator arm. Although the study is described as randomized overall, the record specifically labels sildenafil observational; the allocation process and purpose for that arm are not reported in the registry record. There are no arm-specific descriptions for the PF-00489791 doses or placebo.
The recorded enrollment was 48. The study started in 2009-04, and primary completion was recorded as 2010-07. Its status is terminated. The reason for termination is not reported in the registry record, so termination alone does not establish whether it was related to safety, efficacy, recruitment, or another consideration.
The primary endpoint concerned mean change in PVRI over the 4-hour post-dose period on Day 1. The registry lists 14 outcome measures and 100 analyses. The outcomes include additional acute hemodynamic measures at specific post-dose times and over the post-dose interval. The record does not provide the full protocol or statistical analysis plan, so details such as planned contrasts, adjustment methods, or rules for selecting analyses cannot be established from the registry information.
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.
Only the first 6 of 7 groups are shown.
Overall Study
| Stage | Placebo | PF-00489791 1 mg | PF-00489791 2 mg | PF-00489791 4 mg | PF-00489791 10 mg | PF-00489791 20 mg |
|---|---|---|---|---|---|---|
| STARTED | 6 | 7 | 7 | 8 | 6 | 7 |
| Treated | 6 | 6 | 7 | 6 | 6 | 7 |
| COMPLETED | 6 | 6 | 7 | 6 | 6 | 7 |
| NOT COMPLETED | 0 | 1 | 0 | 2 | 0 | 0 |
Reasons for not completing this period:
| Reason | Placebo | PF-00489791 1 mg | PF-00489791 2 mg | PF-00489791 4 mg | PF-00489791 10 mg | PF-00489791 20 mg |
|---|---|---|---|---|---|---|
| Randomized but not treated | 0 | 1 | 0 | 2 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Full analysis set (FAS) included all randomized participants who received study medication. Here, N (overall number of participants analyzed) = participants evaluable for this measure and 'Number Analyzed' = participants who were evaluable at given time points for each group.
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: Safety population included all randomized participants who received study medication.
Only the first 6 of 8 groups are shown.
| Characteristic | Unit | Placebo | PF-00489791 1 mg | PF-00489791 2 mg | PF-00489791 4 mg | PF-00489791 10 mg | PF-00489791 20 mg |
|---|---|---|---|---|---|---|---|
| Participants analysed | 6 | 6 | 7 | 6 | 6 | 7 | |
| Age, Customized: Between 18 and 44 Years | participants | 3 | 2 | 4 | 5 | 2 | 2 |
| Age, Customized: Between 45 and 64 Years | participants | 2 | 1 | 3 | 0 | 2 | 3 |
| Age, Customized: Greater than or equal to (>=) 65 Years | participants | 1 | 3 | 0 | 1 | 2 | 2 |
| Sex: Female, Male: Female | Participants | 5 | 5 | 4 | 4 | 3 | 5 |
| Sex: Female, Male: Male | Participants | 1 | 1 | 3 | 2 | 3 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Mean Change From Baseline in Pulmonary Vascular Resistance Index (PVRI) Over 4 Hours Post Dose, measured over Baseline, up to 4 hours post-dose on Day 1.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | (dyne*s*m^2)/cm^5 |
| Endpoint classification | Continuous Endpoint |
PVRI is an indexed measure of pulmonary vascular resistance. The registry defines it as pulmonary vascular resistance multiplied by body surface area. Pulmonary vascular resistance is calculated from mean pulmonary artery pressure minus pulmonary capillary wedge pressure, divided by cardiac output; cardiac output is taken as the average of triplicate measurements. Body surface area is calculated using height and weight. PVRI values are converted from Wood units to the stated unit, (dyne*s*m^2)/cm^5.
The endpoint is the average of the change from baseline at 1, 2, 3, and 4 hours post dose on Day 1. Averaging these measurements gives one summary of the short-term hemodynamic trajectory over the specified interval, rather than focusing on a single post-dose time point. Baseline provides the reference for expressing change.
As a continuous measure, PVRI can describe the magnitude and direction of hemodynamic change. It is a physiological endpoint, not a direct measure of how participants felt, functioned, or experienced longer-term outcomes. The registry record does not report the numerical endpoint results, so the direction, size, and uncertainty of observed changes cannot be described from the record information available.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary endpoint and describes how it was calculated, but it does not report numerical results for that endpoint. Consequently, no conclusion about the observed mean change, differences between study groups, or precision of those estimates can be drawn from the recorded information. A study objective or endpoint definition describes what was assessed, not what the data showed.
The endpoint averages baseline changes at 1, 2, 3, and 4 hours after dosing on Day 1. Such a summary targets an acute response over a defined interval. It does not by itself establish how measurements changed after that interval or whether any acute change corresponded to later outcomes. The record also lists time-specific hemodynamic outcomes, but their numerical findings are not reported in the registry record.
The recorded enrollment of 48 describes the study as a whole. It should not be treated as the analyzed sample size for the primary endpoint or for any particular arm. The primary-outcome population description says participants had to be randomized and receive study medication to be included in the full analysis set, and the number analyzed could vary by time point. Arm-specific and time-specific analysis counts are not reported in the registry record.
There is also no basis in the record for ranking the dose groups by observed response or describing a dose-response pattern. Five PF-00489791 doses were listed, but the outcome estimates and relevant comparisons are absent. The presence of placebo and an observational sildenafil arm does not substitute for results or establish that all arms were compared in the same way.
In general, a confidence interval expresses uncertainty around an estimate, with narrower intervals indicating greater precision under the method used. No confidence intervals or equivalent uncertainty estimates for the primary endpoint are reported in the registry record. Likewise, no primary-outcome test statistics or p-values are reported. The evidence available for interpretation is therefore about study design, endpoint definition, and recorded safety counts, not comparative efficacy estimates.
The registry status is terminated, but the reason is not reported in the registry record. It would be inappropriate to infer a reason from the status alone. The record also does not describe whether study conduct or analysis departed from the original plan. These gaps limit interpretation independently of the absence of numerical primary results.
9. Statistical Methods Explained
What does a mean change represent?
For a continuous outcome such as PVRI, a mean summarizes the average value in a group. A change from baseline expresses each participant's follow-up value relative to that participant's baseline, and a group mean summarizes those changes. The registry specifies that the primary measure averages changes at 1, 2, 3, and 4 hours after dosing on Day 1. A group mean alone does not show how individual participants varied around that average. The endpoint description names standard deviation as the measure of dispersion, but the numerical means and standard deviations are not reported in the registry record.
Comparative interpretation requires more than knowing that changes were calculated. It depends on the estimated contrast between relevant groups, its uncertainty, and the analysis population. Those numerical results are not reported in the registry record. No treatment comparison or uncertainty interval can be reconstructed from the endpoint definition or enrollment alone.
Why does the endpoint calculation matter?
The endpoint combines pressure measurements, cardiac output, and body surface area according to the registry's stated formulas. Averaging triplicate cardiac output measurements is part of the definition, as is averaging changes across the post-dose time points. These choices define the measure being analyzed; they do not establish that the measure was complete for every participant or that the same number contributed at every time point.
When a derived outcome depends on multiple measurements, its interpretation depends on the underlying measurements and the procedures used to obtain them. The record provides the PVRI formula but does not report further measurement-quality procedures, handling of incomplete component measurements, or the statistical method used to estimate the primary comparisons.
How should a mean difference be interpreted?
In general, a difference between group means describes how far apart the group averages are on the outcome scale. A confidence interval gives a range of values compatible with the data and the assumptions of the method; it communicates precision, not certainty that a particular value is true. A p-value, when reported, summarizes how unusual the data would be under a specified null model. It does not measure the size or clinical importance of an effect. These are general statistical explanations, not descriptions of numerical findings from this study.
For this study, numerical group means, contrasts, confidence intervals, and p-values for the primary endpoint are not reported in the registry record. The record therefore does not support a statement about the magnitude, direction, or statistical uncertainty of a primary comparison. Nor does it establish that a particular dose differed from placebo.
What do the planning assumptions mean?
The sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not the study's observed results. The registry record does not report the trial's own sample-size justification. Because the numerical effect and planning outputs are not included in the record information, no participant requirement can be stated for a particular comparison.
In general, a sample-size calculation depends on the effect targeted, outcome variability, significance level, allocation, and analysis assumptions. Planning around a smaller target effect will generally require more information than planning around a larger target effect, all else equal. This is a general principle, not a numerical calculation for this trial. The enrolled total of 48 should not be presented as proof that the study had a particular level of power.
Why can variability and over-dispersion matter?
Standard deviation describes spread around a mean. Greater variability makes a group mean less precise for a given amount of data. Over-dispersion is a general concern when variability exceeds what a statistical model assumes; it can make uncertainty estimates too small if the model does not accommodate the extra variability. The primary outcome is continuous and its stated dispersion is standard deviation, but the registry record does not report the numerical variability or model diagnostics needed to assess this concern for the trial.
Repeated measurements across post-dose times can also raise questions about how within-participant correlation is handled. Measurements from the same participant are generally related, and analysis choices can affect uncertainty. The registry record defines the endpoint as an average of the changes at the specified times, but it does not report further details about the analysis model or covariance assumptions. No specific method should be attributed to the investigators without that information.
What does the analysis population description tell us?
The full analysis set is described as all randomized participants who received study medication. For the primary measure, the overall analyzed number is participants evaluable for that measure; the number analyzed can differ at particular time points. This definition clarifies that enrollment and analysis counts are not necessarily interchangeable. It does not reveal how many participants were evaluable, why any measurements were unavailable, or what methods were used to address missing observations.
The record lists 100 analyses across 14 outcome measures. In general, assessing many outcomes or contrasts can create multiplicity: the chance of at least one nominally unusual result can rise when many tests are considered. Methods such as prespecifying a primary comparison or adjusting for multiple testing can address that issue, but the registry record does not report the statistical plan or the multiplicity procedure. The count of analyses alone does not establish which tests were confirmatory, whether adjustment occurred, or how results should be prioritized.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 14 outcome measures and 100 analyses, including a primary measure and multiple secondary hemodynamic outcomes. The primary outcome is described as mean change in PVRI over the post-dose period, but the available record information does not identify a single reported comparison or provide numerical results. The analysis listing includes multiple categories or time points, and the primary outcome was not reduced to one comparison. Therefore, there is no single estimate to interpret as the definitive primary contrast.
In general, multiplicity arises when several outcomes, time points, doses, or comparisons are tested. Without an analysis plan, it is not possible to determine which tests were prespecified as primary, whether any adjustment was planned or performed, or how the many analyses were intended to support conclusions. The statistical plan and any interim analyses are not reported in the registry record. No assumptions about their presence or absence should be made.
The full analysis set is defined as randomized participants who received study medication. The number evaluable for the primary measure and the number analyzed at each time point may differ. The registry record does not report those counts, the extent or pattern of missing data, reasons for missingness, or methods used to handle missing observations. It also does not report whether any sensitivity analyses assessed the influence of missing data.
These omissions affect both multiplicity and missing-data interpretation. Even if a numerical estimate were available, the analysis population, missingness, and multiplicity approach would be needed to understand how robustly it answers the stated question. Here, the numerical primary-outcome findings are not reported in the registry record, so those interpretive checks cannot be performed.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Placebo | 2 | 6 | 33.3% |
| PF-00489791 1 mg | 0 | 6 | 0.0% |
| PF-00489791 2 mg | 0 | 7 | 0.0% |
| PF-00489791 4 mg | 0 | 6 | 0.0% |
| PF-00489791 10 mg | 0 | 6 | 0.0% |
| PF-00489791 20 mg | 1 | 7 | 14.3% |
| Sildenafil | 0 | 6 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Placebo | 2 of 6 |
| PF-00489791 1 mg | 4 of 6 |
| PF-00489791 2 mg | 2 of 7 |
| PF-00489791 4 mg | 5 of 6 |
| PF-00489791 10 mg | 4 of 6 |
| PF-00489791 20 mg | 2 of 7 |
Most frequent serious adverse event terms
| Event term | Organ system | Placebo | PF-00489791 1 mg | PF-00489791 2 mg | PF-00489791 4 mg | PF-00489791 10 mg | PF-00489791 20 mg |
|---|---|---|---|---|---|---|---|
| Cardiac failure congestive | Cardiac disorders | 0 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 1 of 7 |
| Haemorrhoids | Gastrointestinal disorders | 1 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 0 of 7 |
| Chest pain | General disorders | 1 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 0 of 7 |
| Oedema peripheral | General disorders | 1 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 0 of 7 |
| Vulval cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 5 | 0 of 5 | 0 of 4 | 0 of 4 | 0 of 3 | 1 of 5 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Placebo | PF-00489791 1 mg | PF-00489791 2 mg | PF-00489791 4 mg | PF-00489791 10 mg | PF-00489791 20 mg |
|---|---|---|---|---|---|---|---|
| Nausea | Gastrointestinal disorders | 1 of 6 | 2 of 6 | 0 of 7 | 1 of 6 | 0 of 6 | 0 of 7 |
| Haematoma | Vascular disorders | 0 of 6 | 0 of 6 | 0 of 7 | 2 of 6 | 0 of 6 | 1 of 7 |
| Vomiting | Gastrointestinal disorders | 0 of 6 | 1 of 6 | 0 of 7 | 1 of 6 | 0 of 6 | 0 of 7 |
| Asthenia | General disorders | 0 of 6 | 0 of 6 | 0 of 7 | 1 of 6 | 1 of 6 | 0 of 7 |
| Headache | Nervous system disorders | 0 of 6 | 0 of 6 | 0 of 7 | 2 of 6 | 0 of 6 | 0 of 7 |
| Proteinuria | Renal and urinary disorders | 0 of 6 | 0 of 6 | 1 of 7 | 0 of 6 | 1 of 6 | 0 of 7 |
| Hypotension | Vascular disorders | 0 of 6 | 1 of 6 | 0 of 7 | 0 of 6 | 1 of 6 | 0 of 7 |
| Eosinophilia | Blood and lymphatic system disorders | 1 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 0 of 7 |
| Tachycardia | Cardiac disorders | 0 of 6 | 0 of 6 | 0 of 7 | 0 of 6 | 1 of 6 | 0 of 7 |
| Ventricular extrasystoles | Cardiac disorders | 0 of 6 | 1 of 6 | 0 of 7 | 0 of 6 | 0 of 6 | 0 of 7 |
Serious events with the highest arm-level rate: vulval cancer (20.0%), haemorrhoids (16.7%), chest pain (16.7%), oedema peripheral (16.7%), cardiac failure congestive (14.3%).
The registry reports participants affected by serious adverse events and by other adverse events for each group. For serious adverse events, the recorded figures are 2 of 6 for placebo, 0 of 6 for PF-00489791 1 mg, 0 of 7 for PF-00489791 2 mg, 0 of 6 for PF-00489791 4 mg, 0 of 6 for PF-00489791 10 mg, 1 of 7 for PF-00489791 20 mg, and 0 of 6 for sildenafil. These are participant counts, not a measure of event severity or duration.
The corresponding counts for other adverse events are 2 of 6 for placebo, 4 of 6 for PF-00489791 1 mg, 2 of 7 for PF-00489791 2 mg, 5 of 6 for PF-00489791 4 mg, 4 of 6 for PF-00489791 10 mg, 2 of 7 for PF-00489791 20 mg, and 3 of 6 for sildenafil. The small group counts mean that these figures describe the recorded participants in this study and should not be treated as precise estimates of event frequency in a broader population.
The listed top serious-event terms are Vulval cancer, 20.0%; Haemorrhoids, 16.7%; Chest pain, 16.7%; Oedema peripheral, 16.7%; and Cardiac failure congestive, 14.3%. The record information does not specify the denominators or arm attribution for these term percentages. Death counts are not reported in the registry record; a missing death count should not be read as zero deaths.
12. What the Result Does, and Does Not, Mean
The record establishes that this was a randomized, masked, parallel-group phase 2a study of several PF-00489791 doses, with placebo and an observational sildenafil arm. It also defines an acute primary hemodynamic endpoint and records safety counts. These registry entries describe the study question and parts of its conduct; they do not establish the direction or size of a treatment effect.
The primary outcome results are not reported in the registry record. It is therefore not possible to say what mean changes were observed, whether groups differed, how precise any estimate was, or whether the data followed a dose-response pattern. The endpoint definition does not substitute for outcome results, and the sample-size assumptions do not establish observed power.
The recorded adverse-event counts are descriptive. They do not, by themselves, establish that an event was caused by a study intervention or that apparent differences between groups are reliable. The recorded groups are small, and the serious-event term percentages lack reported denominator and arm details in the available record information. Deaths are not reported, which is distinct from a recorded count of zero.
In general, a short-term physiological measure can inform understanding of acute changes, but it does not automatically answer questions about long-term outcomes or participant experience. The primary endpoint covers up to 4 hours post dose on Day 1. The record does not report longer-term primary results or establish how these measurements relate to later outcomes.
The appropriate reading is consequently limited: the registry describes the planned acute hemodynamic question, study design, endpoint calculation, and selected safety counts. It does not provide the numerical primary efficacy results needed to characterize comparative findings. The trial's terminated status also has no stated explanation in the registry record and cannot be used to infer a favorable or unfavorable result.
13. Why This Trial Matters Statistically
This trial is statistically notable for the structure of its question: several doses of one intervention were studied against placebo, with an additional sildenafil arm explicitly described as observational. A dose-response question can involve several related contrasts, making it important to distinguish the main planned comparison from exploratory or secondary analyses. The registry lists many outcome analyses, but does not report the statistical plan needed to establish that hierarchy.
The endpoint is a derived continuous measure built from hemodynamic components and averaged over several post-dose measurements. That definition illustrates how decisions about measurement, time points, and summary statistics shape the question an analysis answers. A mean over the interval represents a different target from a single-time-point change or a maximum change, even when all use the same underlying measurements.
There is also a distinction between the total enrolled and the participants evaluable for an outcome. The primary-outcome description anticipates that analysis counts can vary by time point. Without those counts and missing-data methods, readers cannot assess how much information supports each estimate or whether availability of measurements could affect interpretation.
Finally, the record illustrates the importance of separating a registered objective from reported evidence. It provides detailed endpoint definitions and records safety counts, yet the numerical primary outcome results are not reported in the registry record. Statistical interpretation requires estimates and uncertainty, not just a design or a list of analyses. The stated planning assumptions are not observed power and cannot fill that evidentiary gap.
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.
A central limitation is that numerical primary-outcome results are not reported in the registry record. This prevents assessment of the observed change, group contrasts, variability, and precision. The registry information also does not give numerical findings for the listed secondary hemodynamic outcomes, so those measures cannot provide a results-based context for the primary endpoint.
The reason the study was terminated is not reported in the registry record. The record does not describe recruitment or conduct issues, protocol deviations, or whether the trial stopped for a planned or unplanned reason. None of these possibilities can be inferred from the status label.
The record lists an enrollment of 48 but does not report arm-specific enrollment or the number analyzed for each outcome and time point. The full analysis set definition requires randomization and receipt of study medication, and the measure-specific population is evaluable participants. Missing-data amounts, reasons, and handling methods are not reported.
Although 14 outcome measures and 100 analyses are listed, the statistical analysis plan, multiplicity strategy, interim analyses, and planned primary contrasts are not reported in the registry record. The record also does not provide the trial's own sample-size justification. The planning assumptions do not replace such a justification and are not observed power.
Safety interpretation is limited by the recorded group counts and the lack of denominator and arm details for the serious-event term percentages. Death counts are not reported. These limitations are specific to the information available for this study and constrain both comparative efficacy interpretation and a full appraisal of safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Research Study To Assess The Effectiveness And Safety Of Different Doses Of Oral PF-00489791 In The Treatment Of Adult Patients With Pulmonary Arterial Hypertension — NCT00853112.
- Registry record last updated 2017-10-24; status last verified 2017-09.
- Results first posted 2017-10-24.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00853112 is a phase 2a randomized, triple-masked, parallel-group study of oral PF-00489791 for pulmonary arterial hypertension. The official title describes idiopathic and familial disease and a placebo-controlled investigation of dose response in acute hemodynamics. Five PF-00489791 doses, placebo, and an observational sildenafil arm are listed. Enrollment was 48; the study started in 2009-04, primary completion was recorded in 2010-07, and its status is terminated.
The primary endpoint was mean change from baseline in PVRI over 4 hours post dose on Day 1. The registry defines its calculation but does not report numerical primary-outcome results. It lists 14 outcome measures and 100 analyses. Serious and other adverse-event participant counts are recorded by group, while death counts and the reason for termination are not reported in the registry record.