Bioequivalence Study of Favipiravir 200 mg Film Tablet (Novelfarma, Turkey) Under Fasting Conditions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Bioequivalence Study of Favipiravir 200 mg Film Tablet (Novelfarma, Turkey) Under Fasting Conditions (NCT04400682), a randomized phase 1 study. The primary outcome is AUC0-tlast.

2. Clinical Question

The study was randomized, open-label, and used a two-period crossover design. Each sequence received both products, but in a different order. This makes the comparison a within-participant comparison in the intended design: each participant can contribute observations under both products. The registry record reports outcome summaries and a sponsor analysis, but does not provide participant-level measurements or a full account of the analysis population. The posted results therefore support a description of the recorded pharmacokinetic comparison, not conclusions beyond the measured endpoint and the population enrolled.

3. Trial Design

This completed Phase 1 trial was a randomized, open-label, single-dose, two-period crossover study under fasting conditions. The registry lists enrollment of 30 healthy male subjects. Participants were assigned to one of two sequences: Favira followed by Avigan, or Avigan followed by Favira. The arm descriptions state that a 48-hour washout separated the periods. Both products were 200 mg favipiravir film tablets, and the brief summary describes administration with 240 mL of water at room temperature. The registry also mentions current pandemic precautions, without giving further details.

Because participants received both products in sequence, the central comparison is not simply between separate groups that each received only one product. The crossover structure can allow each participant to serve as a reference for their own response, which can reduce the influence of stable differences between participants. This benefit depends on analysis that respects the pairing and period and sequence structure. The registry lists ANOVA for the sponsor’s reported mean-ratio analyses, but the full model specification, handling of period and sequence, and analysis population are not reported in the registry record.

The primary outcome was AUC0-tlast of favipiravir, specified over 0 to 24 hours post dose. Two secondary outcomes are listed: AUC0-inf and Tmax. The registry reports outcome group summaries for 25 participants under each product. It does not explain how those outcome counts relate to the enrollment figure, whether any participants were excluded from particular analyses, or how missing measurements were handled. The start date is 2020-05-28, primary completion is dated 2020-06-05, and the study status is completed. The record does not describe masking, which is listed as none, or report a detailed protocol rationale for the design or its original sample-size assumptions.

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: 46 subjects screened

Period 1

Reasons for not completing this period:

Period 2

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 AUC0-tlast, measured over 0 to 24 hours post dose.

The primary endpoint, AUC0-tlast, measures the total area under the curve formed by plasma favipiravir concentrations over time, from dosing through the last measured concentration. The registry specifies a timeframe of 0 to 24 hours post dose and gives the unit as ng*hr/mL. A larger area generally reflects greater measured drug exposure across that observation interval; the endpoint is a pharmacokinetic measure, not a direct measure of a clinical health outcome.

AUC is used in bioequivalence comparisons because it captures overall exposure over the measured interval rather than relying on a single concentration reading. In a crossover study, the two products’ exposure can be compared after each participant receives both, subject to appropriate handling of the repeated measurements and the sequence of administration. The registry identifies the primary summary parameter as a least-squares mean with standard deviation, and the sponsor reports an ANOVA mean ratio with a 90% confidence interval.

AUC0-tlast is distinct from AUC0-inf, a secondary endpoint that extends the exposure estimate toward infinity, and from Tmax, which records the time at which the observed concentration reaches its maximum. These endpoints address related but not identical pharmacokinetic features. The registry record does not report the equivalence margin or a detailed rationale for selecting this primary endpoint. Thus, the endpoint’s role can be explained statistically, while the formal basis for declaring equivalence cannot be reconstructed from the posted information alone.

7. Results Posted in the Registry

• AVIGAN (Toyama-Japan): mean 9,908 versus 10,400 on control; difference -492.09 (95% CI -1,961 to 977.14), standardized effect d = -0.19; z-test p = 0.512.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

AUC0-inf of Favipiravir

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AVIGAN (Toyama-Japan): mean 10,186 versus 10,400 on control; difference -213.65 (95% CI -1,694 to 1,266), standardized effect d = -0.08; z-test p = 0.777.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AVIGAN (Toyama-Japan) and the control. The interval gives the range of effects that remain compatible with the data.

Tmax of Favipiravir

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • AVIGAN (Toyama-Japan): mean 0.77 versus 0.77 on control; difference 0.00 (95% CI -0.23 to 0.24), standardized effect d = 0.01; z-test p = 0.973.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between AVIGAN (Toyama-Japan) and the control. The interval gives the range of effects that remain compatible with the data.

The secondary endpoints extend the pharmacokinetic description beyond the primary measure of exposure through the last observed time. AUC0-inf addresses an exposure estimate extended toward infinity, while Tmax describes timing of the observed peak concentration. Across these different measures, the registry’s reported comparisons are broadly consistent with estimates close to little contrast between the products, while the amount of uncertainty depends on the endpoint and its scale. The endpoints are related to the primary result, but they do not replace it or answer precisely the same question.

Secondary results are generally interpreted with less weight than a prespecified primary result. One reason is that examining several outcomes creates more opportunities for apparently notable findings to arise by chance. If many hypotheses are tested, the chance of at least one misleading result can increase unless the analysis plan addresses multiplicity. The registry record lists four outcome measures and three analyses, but does not report a multiplicity adjustment or a hierarchy specifying how the outcomes should be interpreted together.

The secondary estimates should therefore be treated as supportive descriptive evidence, not as independent confirmation of the primary result. Their interpretation also depends on the methods used for each endpoint. The registry provides a sponsor ANOVA analysis for AUC0-inf, but no reported sponsor analysis for Tmax. Recalculated unadjusted comparisons are not a substitute for a prespecified inferential plan, particularly when the crossover pairing and any multiplicity strategy are not fully documented.

In practical statistical terms, concordance across related measures can add context, but does not cure missing information about the formal decision rule, analysis populations, missing data, or adjustment for multiple outcomes. The record supports describing the overall pattern as generally close estimates, while retaining caution about the inferential strength of secondary results.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• AUC0-inf of Favipiravir
• Tmax of Favipiravir

9. Statistical Interpretation

10. Statistical Methods Explained

What does a mean difference describe?

A mean difference expresses the distance between the group means in the original units of the endpoint. For the primary comparison, the recalculated estimate is -492.1 ng*hr/mL for Avigan relative to Favira. The negative sign indicates that the posted Avigan mean is lower on this subtraction scale. The estimate should be read together with its confidence interval, not as a precise value known without uncertainty. A difference on the original scale is intuitive, but it is not the same estimand as a ratio, which compares relative exposure.

Why report a ratio for bioequivalence?

A ratio expresses one product’s estimated exposure relative to the other product’s estimated exposure. A ratio of 1 represents equal values on that scale; values on either side indicate relative differences. The sponsor’s primary result is a mean ratio of 1.015. Bioequivalence assessments commonly rely on a ratio and a confidence interval evaluated against prespecified acceptable limits. This is a general explanation of the statistical idea. The registry record labels the sponsor analysis as EQUIVALENCE, but does not report the limits used, so the criterion cannot be verified from the posted record.

What does ANOVA contribute?

ANOVA is a statistical modeling approach for comparing means while representing sources of variation specified in the model. In a crossover trial, an appropriately specified analysis can account for the repeated observations and other design features. The registry names ANOVA and reports a mean ratio, but it does not provide the complete model formula, variables included, or details of the analysis population. It would therefore be inappropriate to infer which terms were included or how each was handled.

What is the unadjusted recalculation?

The recalculated contrasts use posted group summary statistics rather than individual participant data. They provide a straightforward comparison of the listed means, with uncertainty estimated from the available summaries. For the primary endpoint, the calculation uses an approximate pooled standard deviation, as indicated in the registry data. Since the study is a crossover trial, a calculation based on separate group summaries does not capture the participant-level pairing. It is useful as a descriptive cross-check, but it is not equivalent to a model that uses the crossover structure.

The recalculated p-value is unadjusted and addresses a difference-style comparison under its calculation assumptions. A p-value describes how compatible the observed data are with a specified null model; it is not the probability that the null hypothesis is true and does not measure the size or importance of an effect. The recalculated p-value of 0.512 should not be used as a substitute for the sponsor’s equivalence analysis. A difference test and an equivalence test pose different questions: failure to detect a difference is not itself evidence that two products fall within acceptable equivalence limits.

What does a confidence interval represent?

A confidence interval gives a range of estimates compatible with the observed data under the method’s assumptions. In repeated use of the same method under its assumptions, intervals at a stated confidence level would cover the target parameter at that rate. For an individual trial, the interval is not a guarantee that the true value lies within its endpoints, nor does it describe the range of individual participant responses. The primary recalculation gives a 95% interval for a mean difference; the sponsor’s ANOVA gives a 90% interval for a mean ratio. They refer to different scales and methods, so their widths should not be compared as if they were intervals for the same quantity.

For an equivalence assessment, the interval is considered relative to acceptable limits defined before analysis. If the relevant interval is within those limits, that can support the decision under the chosen procedure. The limits are not reported in the registry record. Consequently, the ratio and interval can be described, but the formal criterion cannot be independently applied. The sponsor’s listed p-value of < 0.001 is displayed to four decimal places; that display should not be read as an exact probability of zero. The record does not explain the test associated with this value.

Why can crossover analysis differ from a simple group comparison?

In a crossover design, each participant receives both products at different periods. Measurements from the same participant are often correlated, because some characteristics remain similar across periods. A paired analysis can use that relationship when estimating the product contrast. Treating the product summaries as if they came from independent groups can fail to represent this correlation and may yield different uncertainty. Period effects, sequence effects, and carryover considerations are also design-specific topics; the registry record does not describe how they were modeled or assessed. The reported 48-hour washout is a design fact, but it does not by itself establish that carryover was absent.

The sponsor’s ANOVA result and the recalculated unadjusted difference therefore should not be expected to match exactly. The sponsor analysis is the result reported for the formal equivalence analysis, while the recalculation is a separate summary-based estimate. Because the discrepancy flag is false, no discrepancy between those outputs is flagged, but the methods and estimands remain different. Interpretation should prioritize the stated analysis while recognizing that the registry record lacks details needed for a full technical audit.

11. Confidence Intervals and Precision

Precision concerns how narrowly an estimate is located by its uncertainty interval. For the primary endpoint, the unadjusted mean-difference estimate is -492.1 ng*hr/mL, with a 95% confidence interval from -1961.0 to 977.1. The range crosses zero and extends to values on both sides of the point estimate. This indicates uncertainty about the direction and size of the unadjusted difference; it does not show that the products are identical.

The sponsor’s ANOVA estimate is a mean ratio of 1.015, with a 90% confidence interval from 0.990 to 1.041. This ratio interval describes uncertainty on a relative scale, whereas the recalculated interval describes uncertainty in the original concentration-time area units. Confidence levels and estimands differ, so the endpoints should not be compared directly as measures of which analysis is more precise. The sponsor’s interval is the one reported with the registry’s equivalence analysis, but the equivalence limits are not reported in the registry record.

Confidence intervals express uncertainty in the estimated population quantity under the analysis assumptions. They do not give the range of values expected for individual participants, nor do they ensure that a future study will produce an estimate inside the interval. Precision is influenced by the amount and variability of information and, in a crossover study, by the within-participant pattern. The registry reports outcome summaries for 25 participants under each product, but does not give the participant-level paired data or enough detail to assess the sponsor model’s uncertainty calculation.

The appropriate conclusion is therefore specific: the posted estimates are close to no relative difference on the ratio scale, while the recalculated difference interval remains broad and includes both negative and positive values. The ratio interval alone cannot establish formal equivalence without the prespecified limits. Missing reporting on exclusions, missing measurements, and the analysis population further constrains evaluation of the precision.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effect, not a report of the trial’s original design calculation. For these continuous outcomes, the figures mean participants per arm, not total events. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect targeted is a stated fraction of the observed effect: 100%, 75%, or 50%. The original sample-size assumptions for this trial are not reported in the registry record.

The 80% power column gives the planning number of participants per arm under which the calculation would have an 80% chance of detecting the specified effect, assuming the stated model and planning inputs. The 90% power column gives the corresponding planning number for a higher chance of detecting that effect. These are design quantities, not evidence about what happened in this completed trial. The listed figures should be read as illustrations for future planning using the posted effect estimate and its variability.

Smaller targeted effects require more participants because a subtler contrast is harder to distinguish from random variation. That is why the planning illustrations increase as the chosen fraction of the observed effect becomes smaller. The values may also be very large when the observed effect is small relative to variability, as is the case for the posted Tmax contrast. Such results are especially sensitive to uncertainty in the estimated effect; the observed effect is not guaranteed to represent the effect in a future study.

This is not observed power. It is a planning calculation conditional on the listed assumptions and observed summary effect, and it does not recover the rationale for the original enrollment target. It also does not establish that the trial was adequately powered for an equivalence objective, since the registry does not report the original planning assumptions or the equivalence margin.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -492.090; pooled standard deviation σ = 2650.305.
2. n = 2 × (1.96 + 0.842)² × 2650.305² / -492.090² = 455.3, rounded up to 456 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -492.09                      # observed difference in means
sigma <- 2650.30537564881                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4400682)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 456 (80% power), 610 (90% power)
 75% of observed effect: n per arm = 810 (80% power), 1,084 (90% power)
 50% of observed effect: n per arm = 1,822 (80% power), 2,439 (90% power)
power.t.test: 456.3 
Simulated power at n = 456 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor’s primary analysis is reported as an ANOVA mean ratio of 1.015, with a 90% confidence interval from 0.990 to 1.041, and is labeled EQUIVALENCE. This is the registry’s own reported analysis for the primary endpoint. The sponsor also reports the displayed p-value of < 0.001. The record does not state the equivalence limits or explain the p-value’s precise role, so those details cannot be independently assessed.

The unadjusted recalculation gives a mean difference of -492.1 ng*hr/mL, with a 95% confidence interval from -1961.0 to 977.1 and p=0.512. It is calculated from posted summary statistics, uses an approximate standard deviation, and does not represent a participant-level crossover model. It also estimates a difference in original units rather than a ratio. The two analyses therefore should not be treated as competing versions of an identical calculation.

The discrepancy flag is false. The sponsor’s analysis remains the relevant reported result for the registry’s equivalence assessment, while the unadjusted calculation serves as a descriptive check on the group summaries. Neither the unadjusted p-value nor the fact that the sponsor’s ratio is near 1 settles the formal equivalence question without the margin and model details. Those are not reported in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when statistical conclusions are drawn from several outcomes, comparisons, or analyses. With repeated testing, a result can appear notable by chance even if none of the underlying effects is meaningful. A prespecified strategy may control that risk, for example by identifying a primary endpoint and defining how secondary results will be tested or interpreted. This is a general statistical consideration; the registry record does not report a multiplicity adjustment, a testing hierarchy, or a detailed plan governing the secondary analyses.

The record identifies AUC0-tlast as the primary endpoint and lists AUC0-inf and Tmax as secondary outcomes. It also reports four outcome measures and three analyses. These listings establish that more than one result was considered, but do not reveal whether all were part of one inferential family or whether some were descriptive. The secondary p-values are unadjusted recalculations, so they should not be treated as multiplicity-controlled evidence. The sponsor’s reported analyses are labeled for equivalence, but the record does not explain how the primary and secondary tests related to each other.

Missing-data handling is also not reported in the registry record. The record gives enrollment of 30 and outcome summaries with 25 participants for each product, but does not explain the difference, report reasons for missing observations, or state whether the same participants contributed to each endpoint. It does not describe imputation, exclusions, or sensitivity analyses. These omissions prevent assessment of whether missingness could have influenced the reported results.

The primary population field is blank, and the registry does not specify an analysis population such as all randomized participants or a subset meeting particular criteria. In a bioequivalence study, analysis populations can matter because inclusion rules and deviations may affect the estimate and its uncertainty. The record also does not report interim analyses, and no such procedure should be inferred. Without a protocol-level statistical plan, the posted results can be described, but the handling of multiplicity, missing measurements, and analysis-set selection cannot be fully evaluated.

16. 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 0% reporting threshold.

The registry reports zero serious adverse events for Favira and zero for Avigan among the listed at-risk groups of 25 for each product. It also reports zero other adverse events and zero deaths for each group. These figures describe what was recorded for the study’s adverse-event summaries; they are not proof that no adverse events occurred outside the reported categories or observation and reporting process.

The trial involved single doses in healthy male subjects, with each product given in a crossover sequence. The registry does not provide further detail on adverse-event definitions, surveillance duration, severity categories beyond serious versus other, or how events were attributed across treatment periods. No serious adverse-event terms are listed. Because the outcome counts are zero in the posted record, there is no event pattern to compare across products in these summaries.

Zero recorded events should be interpreted in the context of the study’s scope and the limited information reported. The figures do not quantify the frequency of uncommon events in broader populations, and the registry does not provide enough information to assess safety beyond these posted counts. This is a statistical description of the adverse-event record, not a treatment recommendation.

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

The results describe pharmacokinetic measurements after single doses of two 200 mg favipiravir film tablets in healthy male subjects under fasting conditions. For AUC0-tlast, the sponsor reports a mean ratio close to 1 and labels the ANOVA result an equivalence analysis. The unadjusted recalculation of the posted summaries reports a difference with a confidence interval that includes zero. These findings are compatible with a limited estimated contrast, but the evidence must be interpreted according to the method and decision rule used.

The result does not, by itself, establish a formal equivalence conclusion that can be independently verified. Such a conclusion depends on a prespecified equivalence margin and an appropriate analysis; the margin is not reported in the registry record. Nor does a nonsignificant difference-style test prove that products are equivalent. The sponsor’s reported result is the relevant registry analysis, but its decision criterion and model details are incomplete in the posted record.

The findings also do not establish clinical benefit, long-term safety, or effects in populations beyond the healthy male subjects studied. The primary endpoint measures plasma exposure over a specified post-dose interval, not a patient-centered clinical outcome. The registry reports zero adverse events in the posted categories, but these counts do not establish the absence of risk in other settings or over longer use.

Interpretation is further limited by the lack of detail on participant flow, missing measurements, analysis populations, and multiplicity. Enrollment is listed as 30, while outcome group summaries list 25 participants for each product, and the record does not explain that difference. The appropriate scope of inference is therefore the recorded pharmacokinetic comparison and safety counts in this particular completed study, with uncertainty and reporting limitations kept explicit.

18. Why This Trial Matters Statistically

This trial offers a useful statistical example because its randomized crossover design and its reported outcome summaries invite different kinds of comparison. A crossover design can make within-participant information important: the analysis should represent how measurements from the same person relate across treatment periods. A simple comparison reconstructed from separate product summaries does not retain that pairing, making it a descriptive check rather than a full reproduction of the sponsor’s model.

The record also illustrates why bioequivalence is not established merely by failing to detect a difference. The recalculated difference estimate and its interval answer a difference-style question, while the sponsor reports a ratio and labels the result an equivalence analysis. A formal equivalence interpretation depends on prespecified limits. Without those limits in the registry record, readers can examine the reported estimate and interval but cannot independently verify the decision rule.

Precision is central to this distinction. Estimates near no contrast can still be uncertain, and a confidence interval must be interpreted against the target question and scale. The primary ratio interval and the unadjusted difference interval are not interchangeable. Their different methods, confidence levels, and estimands make it important to avoid drawing a single conclusion from one statistic in isolation.

Finally, secondary outcomes, missing-data reporting, and sample-size planning all affect how much confidence readers can place in a result. The registry includes several pharmacokinetic measures but does not report a multiplicity strategy or the original sample-size assumptions. Its planning illustrations are not observed power and cannot recover the study’s design rationale. These distinctions matter whenever a statistical record is used to understand what a trial can and cannot establish.

19. 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 record gives limited information for auditing the primary analysis. Although it names ANOVA and reports a mean ratio, it does not provide the complete model specification, the variables included, or the sponsor’s analysis population. The equivalence margin is not reported, so the formal criterion behind the EQUIVALENCE label cannot be independently checked. The displayed p-value is included without an explanation of the test it represents.

The participant counts are also not fully explained. The registry lists enrollment of 30, while the primary outcome summaries report 25 participants for each product. The record does not state why these figures differ, whether the same participants contributed to both product summaries, or whether any observations were excluded. It does not describe missing-data handling or provide participant-level paired results.

The recalculated primary comparison is based on group summaries, uses an approximate standard deviation, and does not retain the crossover pairing. It is therefore less tailored to the design than the sponsor’s ANOVA result. The secondary analyses raise further uncertainty because multiplicity handling is not reported, and a sponsor analysis is absent for Tmax. The record also does not provide the original sample-size assumptions, so the planning illustrations cannot be treated as the rationale for enrollment.

Finally, the study is described as involving healthy male subjects under fasting conditions and single doses. That context limits what the results describe; the registry does not report outcomes in other populations or under other administration conditions. Safety reporting is limited to the posted adverse-event counts, without detailed surveillance or event definitions. These are limitations of the available record and the scope of the study, not evidence that a particular result is invalid.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Bioequivalence Study of Favipiravir 200 mg Film Tablet (Novelfarma, Turkey) Under Fasting Conditions — NCT04400682.
• Registry record last updated 2020-08-11; status last verified 2020-08.
• Results first posted 2020-08-11.
• 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.

23. Record Summary

The registry record describes a completed, randomized, open-label, two-period crossover Phase 1 trial of Favira 200 mg and Avigan 200 mg film tablets in healthy male subjects under fasting conditions. The sequence descriptions state that each participant received both products, separated by a 48-hour washout. Enrollment is listed as 30; outcome summaries report 25 participants for each product.

The primary endpoint was AUC0-tlast over 0 to 24 hours post dose. The sponsor reports an ANOVA mean ratio of 1.015 with a 90% confidence interval from 0.990 to 1.041 and labels the result EQUIVALENCE. The equivalence margin and full analysis details are not reported in the registry record. An unadjusted summary-based recalculation gives a mean difference of -492.1 ng*hr/mL with a 95% confidence interval from -1961.0 to 977.1.

The registry lists AUC0-inf and Tmax as secondary outcomes and reports zero serious adverse events, zero other adverse events, and zero deaths in the posted groups. Missing-data handling, analysis populations, multiplicity procedures, and the trial’s original sample-size assumptions are not reported.