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 Renal Impairment Study of PF-07321332 Boosted With Ritonavir in Adult Participants With Renal Impairment and in Healthy Participants With Normal Renal Function. (NCT04909853), a non-randomized phase 1 study. The primary outcome is Maximum Observed Plasma Concentration (Cmax) of PF-07321332.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04909853 |
| Phase | Phase 1 |
| Condition | Renal Impairment |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 35 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Adults categorized by estimated glomerular filtration rate as having normal renal function or stable mild, moderate or severe renal impairment. The primary pharmacokinetic analysis population included dosed participants with at least one primary pharmacokinetic parameter.
Intervention
A single oral dose of PF-07321332 in combination with ritonavir. Ritonavir is described in the study summary as the pharmacokinetic boosting agent.
Comparator
The study included renal-function groups, including a normal-function control group. Participants were not randomized, so these groups are not a randomized, like-for-like treatment comparison.
Primary question
How does maximum observed plasma concentration of PF-07321332 differ across the renal-function groups after dosing with ritonavir? The registry record names this pharmacokinetic endpoint but does not report its group values or comparisons.
The clinical question is about whether renal function is associated with differences in PF-07321332 exposure, as represented by maximum observed plasma concentration. The study also assessed safety and tolerability, with adverse events and clinical findings among its secondary outcomes. Its design was not intended to compare randomized treatment assignments: all study groups received the same drug combination, while renal-function status defined the groups.
The study summary describes two parts. Part 1 included participants with normal renal function and stable mild or moderate renal impairment. Part 2 included participants with stable severe renal impairment. This grouping permits descriptive pharmacokinetic comparisons across levels of renal function, but it does not establish that renal impairment alone caused any difference. Other features that differ between participants could also contribute, and the registry record does not report an adjusted causal analysis.
The stated primary endpoint is a concentration measure rather than a clinical outcome. It describes the highest observed plasma concentration during the specified sampling period. The registry record does not report the resulting group estimates, their uncertainty, or a statistical test of group differences. Therefore, the research question can be identified from the registration, but the magnitude and precision of any observed pharmacokinetic differences cannot be determined from this record.
3. Trial Design
This was a Phase 1, non-randomized, open-label, parallel study of PF-07321332 boosted with ritonavir. The registry lists enrollment of 35 and describes the study as completed. The study began on 2021-06-15, and primary completion was 2021-10-07. These registry entries describe the study record; they do not by themselves establish how many participants contributed data to each endpoint analysis.
The study had two parts. Part 1 was planned for approximately 24 participants: approximately 8 per group across normal renal function, mild renal impairment and moderate renal impairment. Part 2 was planned for approximately 8 participants with stable severe renal impairment. The registry describes participants as categorized according to estimated glomerular filtration rate. The exact categorization thresholds are not reported in the registry record.
Open-label means the study was not masked. Non-randomized means that assignment to renal-function groups was not randomized. The normal-function group is described as a control group, but it is not a randomized treatment control: renal-function status, rather than assigned treatment, distinguishes the groups. Accordingly, comparisons should be read as pharmacokinetic contrasts between participant groups, not as randomized estimates of treatment effects.
Participants received a single oral dose of PF-07321332 with ritonavir. The primary pharmacokinetic endpoint was maximum observed plasma concentration. Its stated sampling schedule ran from pre-dose through 48 hours post-dose on Day 1, with measurements at 0, 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 24, 36 and 48 hours. The registry also lists safety outcomes and additional pharmacokinetic measures, including concentrations at 12 and 24 hours and time to maximum observed concentration.
The registry record does not report the rationale for the planned group sizes, a formal sample-size justification, or further operational detail about recruitment and group allocation. The planned approximate group sizes should not be treated as the numbers analyzed for each outcome.
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: Participants were grouped on the basis of severity of renal impairment. Severity was evaluated using estimated glomerular filtration rate (eGFR) in milliliter per minute (mL/min) based on chronic kidney disease-epidemiology collaboration (CKD-EPI) formula. Following were the classifications, a) Normal: eGFR greater than or equal to (\>=) 90 mL/min, b) Mild: eGFR 60 to less than (\<) 90 mL/min, c) Moderate: eGFR \>= 30 to \<60 mL/min and d) Severe: eGFR \<30 mL/min and not requiring dialysis.
Part 1
| Stage | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|
| STARTED | 10 | 8 | 9 | 0 |
| Treated | 10 | 8 | 8 | 0 |
| COMPLETED | 10 | 8 | 8 | 0 |
| NOT COMPLETED | 0 | 0 | 1 | 0 |
Reasons for not completing this period:
| Reason | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|
| Assigned but not treated | 0 | 0 | 1 | 0 |
Part 2
| Stage | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 8 |
| COMPLETED | 0 | 0 | 0 | 7 |
| NOT COMPLETED | 0 | 0 | 0 | 1 |
Reasons for not completing this period:
| Reason | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|
| Adverse Event | 0 | 0 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: The pharmacokinetic (PK) parameter analysis population included all participants dosed who had at least 1 of the PK parameters of primary interest
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 analysis set included all participants randomly assigned to study intervention and who took at least 1 dose of study intervention.
| Characteristic | Unit | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 10 | 8 | 8 | 8 | 34 | |
| Age, Continuous | Years | 61.1 (SD 3.03) | 63.8 (SD 9.07) | 62.0 (SD 8.57) | 62.1 (SD 9.46) | 62.2 (SD 7.45) |
| Sex: Female, Male: Female | Participants | 3 | 3 | 3 | 2 | 11 |
| Sex: Female, Male: Male | Participants | 7 | 5 | 5 | 6 | 23 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 4 | 1 | 0 | 4 | 9 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 6 | 7 | 8 | 4 | 25 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 3 | 1 | 6 | 2 | 12 |
| Race (NIH/OMB): White | Participants | 7 | 6 | 2 | 6 | 21 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 0 | 0 | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Maximum Observed Plasma Concentration (Cmax) of PF-07321332, measured over Part 1 and Part 2: 0 (pre-dose), 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 24, 36 and 48 hours post-dose on Day 1.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Geometric Coefficient of Variation |
| Unit | Nanogram per milliliter |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is maximum observed plasma concentration of PF-07321332, expressed in nanograms per milliliter. It is a pharmacokinetic measure: it describes the highest measured concentration in plasma over the stated sampling schedule after dosing. The endpoint is summarized using a geometric mean and geometric coefficient of variation.
In general, maximum concentration is used to characterize peak exposure after a dose. Comparing this measure across renal-function groups can help describe whether observed drug concentrations vary with renal status. It is one part of a pharmacokinetic profile, not a direct measure of a clinical benefit or a complete description of exposure over time. The registry record also names concentrations at 12 and 24 hours and time to maximum concentration as secondary pharmacokinetic outcomes.
In general, a geometric mean is suited to positive measurements that vary multiplicatively and may be right-skewed. It is calculated on a logarithmic scale and then expressed on the original scale. A geometric coefficient of variation describes relative dispersion around that geometric mean; it is not the same as a standard deviation in the original measurement units.
The record specifies the endpoint, units, summary measures, analysis population and sampling times, but does not report the geometric mean, geometric coefficient of variation, or group contrast results. The estimated size and precision of any renal-function-related difference in maximum concentration are therefore not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registration identifies the study question and the intended pharmacokinetic endpoint, but it does not include the numerical primary endpoint results. No group estimates for maximum observed plasma concentration, uncertainty intervals, or inferential test results are reported in the registry record. Consequently, the size, direction and precision of any differences between renal-function groups cannot be interpreted from this record.
The design supports a descriptive comparison of groups defined by renal function after the same single-dose combination. It does not support treating the normal-function group as a randomized control, because the study was non-randomized. In general, non-randomized group differences can reflect both the characteristic used to define the groups and other participant differences. The registry record does not report an adjustment strategy that would separate these potential influences.
The primary endpoint is a peak concentration measure. In general, a difference in peak concentration does not by itself describe every aspect of drug exposure. The registry lists other pharmacokinetic measures, but their numerical results are also not reported in the registry record. Thus the registration alone cannot show whether groups differed in those measures, nor whether any peak-concentration pattern was accompanied by a similar pattern elsewhere in the concentration profile.
Safety information is reported as participant counts by renal-function group. The serious adverse event figures list zero affected participants in the normal, mild and moderate groups and one affected participant in the severe group. The registry also lists other adverse event counts by group. These are descriptive observations in a small, non-randomized study; they do not establish comparative risk or determine whether an event was caused by treatment. No deaths are listed in any group.
Planning illustrations associated with a posted effect should be distinguished from trial results. In general, such illustrations describe the sample size that might be required under specified assumptions to detect a chosen fraction of an observed effect. They are not observed power, do not replace the trial’s own design rationale, and are not evidence that the effect is clinically important. The registry record does not report a trial-specific sample-size justification. Any planning values should therefore be understood as hypothetical illustrations rather than as a feature of the original protocol.
Overall, the registry supports a description of the design, endpoint and recorded safety counts, but not a conclusion about the magnitude or precision of pharmacokinetic differences. It also does not provide enough information to assess whether a difference, if present in a separate results display, was adjusted for other characteristics or tested under a prespecified analysis plan.
9. Statistical Methods Explained
The primary endpoint is continuous: each participant’s maximum observed plasma concentration is a measured quantity. The registry specifies that the result is summarized as a geometric mean with a geometric coefficient of variation. It does not report the participant-level observations, group summaries, uncertainty intervals or inferential tests in the record.
Why use a geometric mean?
General explanation: concentration measures are positive and often have multiplicative rather than additive variation. A geometric mean is obtained by working with logarithms of the observations, averaging on that scale, and transforming back. This gives a central summary that is less dominated by a small number of high values than an arithmetic mean can be when data are right-skewed. The registry’s choice of a geometric mean is consistent with describing a positive pharmacokinetic measure, but no distributional details are reported in the registry record.
General explanation: a geometric coefficient of variation describes the relative spread of values around a geometric mean. It has no concentration units. It should not be interpreted as a confidence interval or as the range containing all participants’ observations. The registry record names this dispersion measure but does not report its values.
What does the sampling schedule contribute?
Maximum observed concentration depends on when samples are collected. The registry specifies measurements at pre-dose and at 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 24, 36 and 48 hours post-dose on Day 1. The maximum observed value is the highest among the recorded samples; it is not necessarily an exact measurement of the true peak between sampling times. In general, more frequent sampling around a concentration peak can better characterize its timing and height, but the registry record does not report a rationale for the selected schedule or the observed timing of individual peaks.
The registry also names time to maximum observed concentration and concentrations at 12 and 24 hours as secondary pharmacokinetic outcomes. In general, these measures provide different views of a concentration-time profile: timing of the peak and concentrations at specified times. The numerical results for those measures are not reported in the registry record.
How should group contrasts be read?
The groups were defined by renal function, not randomized assignment. In general, a group contrast in a non-randomized study is an observed association. It can describe how measurements differed between groups, but differences in other participant characteristics may also matter. Randomization is a method for balancing such characteristics on average; it was not used. The registry record does not report adjusted estimates or enough detail to establish whether potential confounders were addressed.
General explanation: an uncertainty interval around an estimate represents the range of values reasonably compatible with the data and the assumptions of the statistical method. Its width communicates precision; a wider interval indicates less precision. It is not a guarantee that the true value lies within the interval. Since the registry record does not report primary endpoint estimates or intervals, precision cannot be evaluated from the registration details alone.
What do the planning illustrations mean?
The planning assumptions describe an illustrative calculation based on an observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. The stated effect to detect is a fraction of the observed effect. In general, such calculations ask how much information might be needed to detect an effect under those assumptions. They do not establish the original study’s sample-size rationale, and the registry record does not report that rationale.
The planning illustrations are not observed power. In general, observed power calculated from an observed effect does not add a separate measure of evidence beyond the estimate and its uncertainty. A planning calculation is more useful as a hypothetical design exercise: it can show how assumptions about effect size and allocation relate to a potential future study. The record describes the calculations as planning illustrations, not as the basis for the trial’s enrollment.
In general, a normal approximation is a mathematical method that can be used to approximate sampling distributions under specified conditions. Equal allocation means the illustrative calculation assumes the same number of participants in each comparison group. These are assumptions for that calculation, not evidence that the enrolled groups were equal or that the trial followed a randomized allocation plan. Because this was non-randomized, equal allocation in an illustration should not be mistaken for a feature of the clinical study.
The registry identifies the trial as not reduced to one comparison. That fits a study with multiple renal-function groups and several pharmacokinetic and safety outcomes. The record does not report a single common treatment contrast or a complete statistical analysis plan. Any numerical comparisons should therefore be interpreted with attention to which groups and outcomes they represent, and whether they are exploratory or prespecified; those details are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary endpoint and multiple secondary safety and pharmacokinetic outcomes. When several outcomes or group contrasts are examined, the chance of at least one apparently unusual result can increase. General explanation: multiplicity refers to this issue and can be addressed through prespecified testing hierarchies, adjustment procedures, or cautious interpretation of exploratory comparisons. The statistical plan for handling multiplicity is not reported in the registry record.
The study includes normal, mild, moderate and severe renal-function groups across two parts. Multiple possible contrasts can arise among groups, but the registry record does not state which contrasts were prespecified, whether all were tested, or whether any adjustment for multiple comparisons was planned. The record also does not report whether the secondary measures were treated as confirmatory or descriptive.
The primary pharmacokinetic analysis population is described as dosed participants who had at least one primary pharmacokinetic parameter. This definition explains an eligibility condition for that analysis, but the number included in each group and the handling of missing endpoint measurements are not reported in the registry record. It is also not reported how missing values, incomplete sampling, or observations below a quantification limit were handled.
The registry record does not report an interim analysis plan, missing-data assumptions, sensitivity analyses, or a detailed statistical analysis plan. These omissions limit assessment of how the reported analyses, if considered alongside other posted results, were selected and how robust they are to incomplete data. They do not establish that a particular method was or was not used; those details are simply not reported in the registry record.
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 |
|---|---|---|---|
| Part 1: Normal Renal Function | 0 | 10 | 0.0% |
| Part 1: Mild Renal Impairment | 0 | 8 | 0.0% |
| Part 1: Moderate Renal Impairment | 0 | 8 | 0.0% |
| Part 2: Severe Renal Impairment | 1 | 8 | 12.5% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Part 1: Normal Renal Function | 0 of 10 |
| Part 1: Mild Renal Impairment | 0 of 8 |
| Part 1: Moderate Renal Impairment | 0 of 8 |
| Part 2: Severe Renal Impairment | 0 of 8 |
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 |
|---|---|
| Part 1: Normal Renal Function | 2 of 10 |
| Part 1: Mild Renal Impairment | 1 of 8 |
| Part 1: Moderate Renal Impairment | 1 of 8 |
| Part 2: Severe Renal Impairment | 5 of 8 |
Most frequent serious adverse event terms
| Event term | Organ system | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|---|
| Pneumonia | Infections and infestations | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Acute kidney injury | Renal and urinary disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Pulmonary oedema | Respiratory, thoracic and mediastinal disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Part 1: Normal Renal Function | Part 1: Mild Renal Impairment | Part 1: Moderate Renal Impairment | Part 2: Severe Renal Impairment |
|---|---|---|---|---|---|
| Headache | Nervous system disorders | 2 of 10 | 0 of 8 | 1 of 8 | 0 of 8 |
| Dry mouth | Gastrointestinal disorders | 0 of 10 | 0 of 8 | 0 of 8 | 2 of 8 |
| Asthenia | General disorders | 0 of 10 | 0 of 8 | 0 of 8 | 2 of 8 |
| Dysgeusia | Nervous system disorders | 0 of 10 | 0 of 8 | 0 of 8 | 2 of 8 |
| Anaemia | Blood and lymphatic system disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Thrombocytopenia | Blood and lymphatic system disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Bradycardia | Cardiac disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Nausea | Gastrointestinal disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Hyperkalaemia | Metabolism and nutrition disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
| Hyponatraemia | Metabolism and nutrition disorders | 0 of 10 | 0 of 8 | 0 of 8 | 1 of 8 |
Serious events with the highest arm-level rate: pneumonia (12.5%), acute kidney injury (12.5%), pulmonary oedema (12.5%).
The registry reports serious adverse event counts by renal-function group. The figures are zero affected participants among 10 at risk in the normal-function group, zero among 8 in the mild-impairment group, zero among 8 in the moderate-impairment group, and one among 8 in the severe-impairment group. No deaths are listed in any group. These counts describe what is recorded for this study; they are not estimates of comparative risk.
The registry also reports other adverse event counts: 2 among 10 at risk in the normal-function group, 1 among 8 in the mild group, 1 among 8 in the moderate group, and 5 among 8 in the severe group. The registry lists pneumonia, acute kidney injury and pulmonary oedema among the top serious event terms, each at 12.5%. These figures should be read as reported, without inferring that the events were caused by the study drug.
In general, adverse event counts in a small non-randomized study are descriptive. Differences between groups may be influenced by group size, participant characteristics and chance, and the study does not create randomized groups for a like-for-like safety comparison. The registry record does not report further details needed to assess event timing, duration, clinical course or attribution beyond the listed categories.
12. What the Result Does, and Does Not, Mean
This study is designed to characterize pharmacokinetics, safety and tolerability of a single oral dose of PF-07321332 with ritonavir in adults across renal-function groups. The primary question concerns maximum observed plasma concentration. The registry record defines the endpoint and identifies the analysis population, but does not report the primary endpoint results. It therefore cannot establish the direction, magnitude or precision of any group difference.
The design is non-randomized and open-label. In general, the observed group contrasts describe measurements among people categorized by renal function; they do not isolate the causal effect of renal impairment from other differences between participants. The normal-function group provides a descriptive reference, not a randomized treatment control. The registry record does not report an adjusted analysis that would address this limitation.
The posted safety counts describe recorded events, including one participant with a serious adverse event in the severe-impairment group and none in the other listed groups. Such counts do not establish comparative safety, and they do not show that an event was caused by treatment. No deaths are listed. The record does not report the additional details needed for a fuller evaluation of event characteristics or causality.
In general, pharmacokinetic measurements and clinical outcomes answer different questions. A concentration measure describes drug exposure; it does not by itself demonstrate a clinical benefit, harm, or treatment effect. The registry lists safety outcomes and additional pharmacokinetic measures, but their full numerical results are not reported in the registry record.
Planning illustrations based on observed effects are hypothetical design exercises, not results from a future or current trial and not observed power. They should not be confused with the original design justification, which is not reported in the registry record. Overall, the record establishes what the study set out to measure and reports selected safety counts, but leaves the numerical primary pharmacokinetic findings and important analysis details unreported.
13. Why This Trial Matters Statistically
Renal function can be relevant to pharmacokinetic characterization, so a study that compares drug concentrations across renal-function categories addresses an important design question: whether exposure measurements vary across those groups. This trial is specifically structured around that question and includes normal renal function alongside mild, moderate and severe impairment categories. Its primary endpoint, maximum observed plasma concentration, is a clearly defined measure of peak exposure.
The study also illustrates how design determines the strength of interpretation. Because participants were not randomized and groups were formed by renal-function status, the comparisons are descriptive rather than randomized causal contrasts. That distinction matters when interpreting any difference: observed group variation cannot automatically be attributed to renal function alone.
Statistically, the endpoint is summarized with a geometric mean and geometric coefficient of variation, which are useful descriptors for positive concentration measurements that may vary multiplicatively. The stated sampling schedule also makes clear that the maximum is the greatest measured value at specified times, not necessarily the exact peak at every instant.
The record has limits as an evidence source. It does not report numerical primary pharmacokinetic results, uncertainty intervals, the detailed statistical plan, or the rationale for the planned group sizes. Safety counts are available but remain descriptive. Recognizing these boundaries is important: a registration can explain the intended measurements and structure of an investigation without supplying enough results to judge the size or precision of its findings.
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 main interpretive limitation is that numerical results for the primary pharmacokinetic endpoint are not reported in the registry record. Without group estimates and measures of uncertainty, the magnitude, direction and precision of differences in maximum observed concentration cannot be assessed. The numerical results for the listed secondary pharmacokinetic measures are also not reported.
The non-randomized design means that renal-function groups may differ in other ways as well. The registry record does not report an adjusted comparison or the variables that might have been considered in one. Open-label conduct also means the study was not masked, although the extent to which this could affect measurement or assessment is not reported.
The primary analysis population is defined, but the numbers analyzed by group, the completeness of sampling and the handling of missing measurements are not reported in the registry record. The thresholds used to categorize renal function, further details on participant characteristics, and the rationale for the group sizes are also not reported. Planned approximate group sizes should not be substituted for outcome-specific analysis counts.
The safety data are counts from a non-randomized study. They cannot alone establish comparative risk or causation, and the record does not provide detailed event timing, duration or course. The statistical analysis plan, treatment of multiple comparisons, interim analyses and sensitivity analyses are not reported in the registry record. These gaps limit assessment of both the precision of estimates and the robustness of any results presented elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Renal Impairment Study of PF-07321332 Boosted With Ritonavir in Adult Participants With Renal Impairment and in Healthy Participants With Normal Renal Function. — NCT04909853.
- Registry record last updated 2023-08-02; status last verified 2022-09.
- Results first posted 2023-08-02.
- 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.
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18. Record Summary
NCT04909853 is a completed Phase 1, non-randomized, open-label, parallel study sponsored by Pfizer. It examined a single oral dose of PF-07321332 with ritonavir in adults categorized by renal function. The registry lists enrollment of 35 and describes two parts: normal, mild and moderate renal-function groups in Part 1, and a severe-impairment group in Part 2.
The primary endpoint was maximum observed plasma concentration, summarized as a geometric mean and geometric coefficient of variation. Its sampling schedule ran from pre-dose through 48 hours post-dose on Day 1. The primary pharmacokinetic analysis population included dosed participants with at least one primary parameter. Numerical primary endpoint results and the detailed statistical plan are not reported in the registry record.
Safety counts are listed by group, including one serious adverse event in the severe-impairment group and no deaths. Because the study was non-randomized, group contrasts are descriptive rather than randomized comparisons.