STUDY OF PF-07321332 IN HEALTHY PARTICIPANTS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for STUDY OF PF-07321332 IN HEALTHY PARTICIPANTS (NCT04756531), a randomized phase 1 study. The primary outcome is Number of Participants With Treatment Emergent Adverse Events (TEAEs) in PART-1: SAD.

2. Clinical Question

3. Trial Design

This was a Phase 1, randomized, double-blind, sponsor-open, placebo-controlled study in healthy participants. Its stated aims were to evaluate the safety, tolerability and pharmacokinetics of PF-07321332. The design included single- and multiple-dose escalation. The registry record lists a crossover model, but does not report enough detail to explain the sequence, periods, washout conditions or the role of crossover in each treatment part.

The recorded enrollment was 70, and the trial status is completed. The registry record gives a start date of 2021-02-11 and a primary completion date of 2021-09-01. These dates describe the trial record; they do not establish when each participant received each regimen or how long each participant was followed.

The listed interventions span PF-07321332 dose levels and formulations, with some regimens involving RTV or fed conditions. Placebo regimens are also listed. Arm descriptions identify dose levels, and one description specifies administration with a high fat meal. Detailed allocation across these regimens, treatment sequences and group-specific enrollment are not reported in the registry record.

For the primary safety outcome, the analysis population was defined as participants who received at least 1 dose of study intervention. That definition identifies who could contribute to the outcome, but the analysis counts for each treatment group are not reported as a single comparison. The registry record does not state the randomization ratio or provide the full statistical plan, including how the different regimens were intended to be compared.

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: This was a 5-part study combining PART-1: single ascending dose (SAD), PART-2: multiple ascending dose (MAD), PART-3: relative bioavailability/food effect (rBA/FE), PART-4: metabolism and excretion (M\&E) and PART-5: supratherapeutic exposure (SE).

Only the first 6 of 18 groups are shown.

Overall Study

Reasons for not completing this period:

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

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: The baseline analysis population included all participants enrolled in the study.

Only the first 6 of 19 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment Emergent Adverse Events (TEAEs) in PART-1: SAD, measured over Post the single dose of study intervention till up to 36 days.

The primary endpoint is the number of participants with treatment-emergent adverse events (TEAEs) in PART-1: SAD. It is a count of participants who experienced an event, rather than a measure of the number of events or their severity. The endpoint definition describes an adverse event as an untoward medical occurrence temporally associated with study intervention, whether or not considered related to the intervention.

A TEAE was defined as an event with initial onset or increased severity between the first dose and up to 36 days after the last dose. The listed timeframe also describes follow-up after the single dose as extending up to 36 days. The registry record does not resolve how those descriptions apply across the different parts or dosing schedules.

Counting participants with TEAEs is a way to describe the frequency of observed safety events during a specified follow-up period. It can distinguish whether participants experienced an event, without implying that the intervention caused it. The endpoint definition explicitly includes events whether or not they were considered related to study intervention; treatment-related determinations were made by the investigator.

The registry record does not present a single aggregate result or a single treatment comparison for this endpoint. It notes that the primary outcome has several categories or time points and was not reduced to one comparison. Accordingly, the endpoint definition can be described, but an overall comparative estimate cannot be drawn from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: a participant either met the definition of having a TEAE during the specified period or did not. The registry record describes the endpoint as a number of participants, so it is a count rather than a continuous measurement. A count can describe the observed burden of events in a group, but a comparative assessment ordinarily also needs a clearly defined contrast between groups and information about the uncertainty around that contrast.

What does a confidence interval communicate?

General explanation: A confidence interval expresses the statistical uncertainty around an estimated quantity. It gives a range of values that are reasonably compatible with the observed data under the assumptions of the analysis. A narrower interval indicates greater precision; a wider interval indicates less precision. The registry record does not report a confidence interval for the primary endpoint, so precision for a treatment comparison cannot be evaluated from this record.

Why do the group counts not make a treatment comparison?

General explanation: A comparison requires a defined measure, such as a difference or ratio in event frequency, and a method for estimating its uncertainty. Counts are useful descriptive information, but they do not, by themselves, account for the group sizes, the way participants were assigned, or the analysis population. The posted record lists groups and counts but does not provide one consolidated primary-outcome contrast. No recalculated comparison is presented in the registry record.

The trial is described as randomized, double-blind and crossover. Randomization is intended to support fair allocation across treatments, while blinding can limit some forms of influence on care and outcome assessment. In a crossover design, participants may receive more than one regimen in a sequence; analysis can need to account for within-participant dependence and possible period or sequence effects. General explanation: repeated observations from the same participant are not necessarily independent. The registry record does not describe the sequence structure or report an analysis accounting for it, so those design details cannot be evaluated from the posted information.

What does the event definition contribute?

The endpoint definition sets boundaries for what counts as an event and when it counts. It includes untoward medical occurrences whether or not they were considered related to the study intervention. TEAEs are identified by onset or worsening after first dose and through the stated period after the last dose. This temporal definition is important for consistent classification, but it does not establish that the intervention caused an event. The record says treatment-related events were determined by the investigator.

General explanation: In a binary outcome analysis, a participant contributes an event classification rather than an event-rate trajectory. Such an analysis does not preserve all information about how many separate events occurred, how long they lasted or how severe they were unless those features are analyzed separately. The registry record describes serious and other event counts separately in the safety listing, but it does not present a detailed primary-outcome analysis covering these distinctions.

What is over-dispersion, and is it relevant?

General explanation: Over-dispersion refers to greater variability in count data than a statistical model expects. It can matter when analyzing event counts, particularly if a model assumes a particular count distribution. The primary endpoint is specified as the number of participants with TEAEs, not the total number of separate events. The registry record does not report an over-dispersion assessment or a count-model analysis; there is no basis to claim that over-dispersion was present or affected the results.

The record includes a description of planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. It says that the effect to detect is a stated fraction of the observed effect, and distinguishes participant-per-arm illustrations from total-event illustrations for time-to-event outcomes. These are planning assumptions, not observed trial findings. No numerical sample-size illustrations or observed comparative effect for this primary endpoint are reported in the registry record. Such illustrations must not be interpreted as observed power or as the trial’s own design justification.

The record does not report the statistical model, covariate adjustment, handling of repeated measurements, missing-data procedure or multiplicity strategy for the primary endpoint. Those omissions constrain methodological interpretation: it is not possible to determine which analysis assumptions were used or how estimates would change under alternative approaches.

10. Multiplicity, Missing Data and Analysis Populations

The study includes multiple dose levels, formulations, food conditions, treatment parts and pharmacokinetic outcomes. When many outcomes or comparisons are tested, the chance of finding an apparently unusual result can increase. General explanation: Multiplicity procedures can control this risk by adjusting how evidence is assessed across a set of planned tests. The registry record does not report whether multiplicity was addressed, which comparisons were considered primary within each part, or whether any testing hierarchy was used.

The record identifies the primary analysis population as participants who received at least 1 dose of study intervention. It does not report the number analyzed for the primary endpoint by treatment group, nor does it describe how participants with incomplete follow-up were handled. Missing-data methods, reasons for missing observations and sensitivity analyses are not reported in the registry record.

The primary outcome is described as having several categories or time points and is not reduced to one comparison. Consequently, the posted record does not identify one estimate to which a confidence interval or hypothesis test can be attached. There is no reported primary-outcome p-value or multiplicity-adjusted result. The lack of a single comparison should not be interpreted as evidence that no analysis was conducted; it means the analysis details and consolidated result are not reported in the registry record.

The crossover design can also make the analysis population and dependence structure important. The record does not state whether all participants contributed data to each treatment period or how incomplete sequences were addressed. These details matter for understanding the analysis, but they cannot be inferred from the design label alone.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety listing separates serious adverse events, other adverse events and deaths for each listed treatment group. In every group shown, the serious adverse-event count is 0, and the death count is 0. These are group-level descriptive counts as recorded. They do not provide a comparative estimate, establish the absence of unreported events, or rule out events outside the recorded follow-up.

The count for other adverse events is not the same as the serious-event count. The listed groups include both groups with no participants affected by other events and groups with participants affected. For example, the listing records 2 participants affected by other events among 6 at risk in the fasted placebo suspension group, and 4 affected among 8 at risk in the fasted placebo/RTV BID group. These examples describe the listed counts only; they are not evidence that one regimen caused more events than another.

Seriousness and treatment relatedness are distinct classifications. The registry record defines serious events by specified outcomes or investigator judgment, while relatedness was determined by the investigator. The posted safety counts should therefore be interpreted as descriptive reporting, not as a causal assessment or as a substitute for the primary TEAE analysis.

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

This trial’s registry record documents a Phase 1 evaluation of PF-07321332 in healthy participants, designed to examine safety, tolerability and pharmacokinetics across single- and multiple-dose regimens. It provides an operational definition for treatment-emergent adverse events and identifies the population eligible for the primary safety analysis. The safety listing also reports descriptive counts by treatment group.

The record does not provide a single aggregate comparison for the primary endpoint, confidence intervals, p-values or adjusted estimates. It therefore does not establish the size or precision of a difference in TEAEs between PF-07321332 and placebo. The absence of a consolidated estimate is not evidence of equivalence, and the descriptive counts should not be treated as proof of a causal treatment effect.

The listing records no serious adverse events and no deaths in each group shown. This does not mean that the record establishes absence of all safety concerns: event counts are limited to the listed groups and recorded definitions and follow-up. The other-event counts also do not indicate whether events were judged related to treatment unless that classification is specifically reported.

The study concerns healthy participants and its design includes multiple regimens. Its findings, as described in the registry record, should not be extended to other populations or interpreted as a treatment recommendation. The listed pharmacokinetic outcomes indicate what the study planned to assess, but their numerical results are not reported in the record used for this analysis.

13. Why This Trial Matters Statistically

Early-phase studies have a different statistical role from trials designed to estimate clinical benefit in a broad patient population. This study was designed to evaluate safety, tolerability and pharmacokinetics in healthy participants while examining single- and multiple-dose regimens. Its randomized, double-blind and placebo-controlled features are important elements of the design, and the crossover model can affect how repeated treatment observations need to be analyzed.

The record also illustrates why an endpoint definition and a numerical comparison are both needed for interpretation. It carefully defines TEAEs, including the event window and the analysis population. But without a consolidated treatment contrast and a measure of uncertainty, the frequency of the primary outcome cannot be compared statistically across regimens using the registry record alone.

Several intervention conditions are listed, including dose, formulation, food condition and RTV combinations. That range makes transparent reporting of planned comparisons, analysis populations and multiplicity especially useful. The registry record does not report those details in sufficient form to reconstruct the primary analysis. A reader can distinguish the descriptive safety counts from a formal inference, rather than treating each listed count as a standalone comparison.

The record’s value is therefore partly methodological: it exposes the limits of what can be concluded from outcome definitions and group-level counts without an accompanying analysis. The descriptive findings can be read accurately, while avoiding stronger claims about comparative safety or pharmacokinetics than the registry record supports.

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 record does not provide a single aggregate result or a treatment comparison. It also does not report confidence intervals, p-values, adjusted estimates or the statistical model. This prevents assessment of the magnitude and precision of a comparative effect.

Although the design is described as crossover, the record does not give treatment sequences, period details, washout conditions or an analysis of within-participant dependence. The intervention listing includes several doses and conditions, but allocation across groups and group-specific analysis populations are not reported as a consolidated account. The enrollment of 70 should not be read as the number analyzed for every outcome.

The primary endpoint definition includes events whether or not related to intervention, and investigator assessment determined relatedness. The record does not report a primary analysis separating related from unrelated events, or provide event severity and duration details for the endpoint. The listed safety counts are descriptive and cannot substitute for a planned comparison.

Missing-data handling, loss to follow-up, multiplicity procedures, interim analyses and the statistical plan are not reported in the registry record. The record also lists pharmacokinetic secondary outcomes without numerical results in the information used for this analysis. These reporting gaps limit what can be inferred about both the safety analysis and the pharmacokinetic findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: STUDY OF PF-07321332 IN HEALTHY PARTICIPANTS — NCT04756531.
• Registry record last updated 2024-10-15; status last verified 2024-07.
• Results first posted 2024-10-15.
• 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

NCT04756531 is a completed Phase 1 randomized, double-blind, sponsor-open, placebo-controlled crossover study in healthy participants. The registry record describes single- and multiple-dose escalation and an enrollment of 70. The recorded start date is 2021-02-11, and the primary completion date is 2021-09-01.

The primary endpoint is the number of participants with treatment-emergent adverse events in PART-1: SAD. The eligible analysis population included participants who received at least 1 dose. The record defines the event window and lists group-level safety counts, with 0 serious events and 0 deaths in each listed group. It does not report a single aggregate primary-outcome comparison or its statistical uncertainty.

Pharmacokinetic outcomes are listed, but their numerical findings are not reported in the registry record. Analysis details concerning the primary comparison, missing data and multiplicity are also not reported.