FX-322 in Sensorineural Hearing Loss: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for FX-322 in Sensorineural Hearing Loss (NCT03616223), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Treatment-emergent Adverse Event(s) (TEAEs).

2. Clinical Question

This is a safety-focused question, not a direct test of whether hearing changed or whether FX-322 improved hearing. The posted primary outcome counts participants with treatment-emergent adverse events. It does not describe the number of separate events experienced by each participant, their duration, severity, or relationship to study treatment. The record also notes that audiometric and otoscopic treatment-emergent adverse events were recorded according to American Speech-Language-Hearing Association guidelines.

The study compared two FX-322 dose cohorts with placebo cohorts. Because the registry lists no inferential analyses for the primary outcome, the posted counts support a descriptive account of participants with reported events, not a statistically tested treatment contrast. The question should therefore be read as asking what was recorded during the specified safety follow-up, rather than as establishing a causal effect or a difference in risk.

3. Trial Design

The registry describes a phase 1/2, randomized, double-blind, placebo-controlled, parallel-group study. It evaluated a single dose of FX-322 administered by intratympanic injection at two dose levels in adults with stable sensorineural hearing loss. The study included male and female adults otherwise healthy with this condition. The enrollment was 23, and the study status is completed.

The listed treatment groups were FX-322 Low Dose, FX-322 High Dose, Placebo-Low Dose, and Placebo-High Dose. Each was described as a cohort receiving a single intratympanic injection. In the posted primary-outcome results, the low-dose FX-322 group included 7 participants, the high-dose FX-322 group included 8, and each separate placebo group included 4. The record also reports a pooled placebo group of 8 for this outcome. These are the numbers represented in the posted safety results; they should not be confused with the enrollment total or treated as a description of every analysis population.

Randomization and blinding are design features intended to reduce bias, but the registry record does not report how randomization was generated, whether allocation was concealed, or which roles were masked. It identifies masking as quadruple, without describing the masking procedures. Details such as dose amounts, eligibility criteria beyond the general population description, or the timing of assessments other than the outcome timeframe are not reported in the registry record.

The primary safety outcome was assessed from baseline through Day 90. The record also lists pharmacokinetic secondary outcomes: Cmax, Tmax, AUClast, t1/2, and CL/F. Values for these secondary measures are not reported in the registry record. The sponsor is Frequency Therapeutics. The study started on 2018-07-03, reached primary completion on 2018-12-18, and is recorded as completed.

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: 23 participants were randomized into one of four treatment groups using a 1:1 allocation ratio for dose cohort (approximately 12 in each cohort) and a 2:1 allocation ratio for study drug (approximately 8 FX-322:4 placebo) within each cohort. Subjects received a single dose of FX-322L (0.05mL), FX-322H (0.2mL), or matching placebo.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Safety Analysis Set = All subjects exposed to study drug and analyzed according to the actual treatment received regardless of the randomized treatment

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment-emergent Adverse Event(s) (TEAEs), measured over Baseline through Day 90.

The primary outcome is the number of participants with one or more treatment-emergent adverse events, abbreviated TEAEs in the registry. A TEAE is defined as any untoward medical occurrence in a participant administered study drug; the definition does not require a causal relationship with treatment. Events were collected from first dose through the end of study, stated as Day 90. Audiometric and otoscopic TEAEs were recorded according to American Speech-Language-Hearing Association guidelines.

This endpoint is used to summarize safety observations during and after exposure. Counting participants with an event answers how many people were affected, rather than how many event episodes occurred. A participant with multiple events is still counted as a participant with an event for this outcome. The endpoint therefore does not, by itself, communicate event frequency per person, severity, duration, clinical importance, or whether events were judged related to treatment.

The endpoint is reported separately for the FX-322 low-dose and high-dose groups and for placebo groups, including pooled placebo. The Safety Analysis Set includes all participants exposed to study drug and classifies them according to the treatment actually received, regardless of randomized treatment. That definition is relevant when interpreting the group counts: the reported population is exposure-based, rather than simply a count of everyone randomized under their assigned group.

The outcome is suitable for a descriptive safety summary, but its count alone cannot distinguish background events from events caused by treatment. The registry record does not report an inferential comparison or an adjusted effect estimate for this endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design and endpoint determine what the posted numbers can answer. A randomized parallel-group study assigns participants to separate treatment groups and follows those groups concurrently. Randomization is generally intended to make groups comparable with respect to factors that could affect outcomes, while blinding is generally intended to limit the influence of expectations on care, reporting, and assessment. Those are general purposes of these design features; the registry record does not describe the allocation procedure or the practical details of masking, so those procedures cannot be evaluated from the record.

What does a participant count represent?

This is a binary outcome at the participant level: for each person, the question is whether at least one TEAE was recorded during the outcome timeframe. The arm result then counts the participants for whom the answer was yes. It does not count every separate event and does not weight events by severity or duration. This kind of count is useful for a straightforward safety summary, but it compresses potentially different experiences into the same outcome category. A person with one event and a person with multiple events both contribute one participant to the count.

The record defines the primary analysis population as all participants exposed to study drug, classified by the treatment actually received regardless of randomized treatment. This is an exposure-based safety population. It differs conceptually from an analysis that classifies everyone only by randomized assignment, because the actual treatment received determines the group label for this safety summary. The record does not report how many participants, if any, received a treatment different from the one randomized.

Why do denominators and uncertainty matter?

A count is most informative when read alongside the number of participants contributing to it. The posted groups are small cohorts, and the reported counts are accompanied by group sizes. In small groups, each participant contributes substantially to the descriptive total, and the observed count can be sensitive to the experience of individual participants. General statistical reasoning therefore cautions against treating the count as a highly precise estimate of the event pattern that would occur in a broader population.

A confidence interval is a general statistical tool for expressing uncertainty around an estimate. It describes a range of values compatible with the data under a specified method, rather than guaranteeing that the true value lies in that range. No confidence interval for the primary outcome is reported in the registry record. A p-value, in general, assesses how compatible data are with a specified null hypothesis under a statistical model; it does not measure the size or importance of an effect. The registry record reports no p-value or formal test for the primary outcome.

Why is a two-group comparison not available?

The outcome is binary, so a comparison between two groups would ordinarily require a defined contrast and a statistical method appropriate for event counts or proportions. The registry record states that values are missing or not estimable for a two-arm comparison of this endpoint, and it lists zero analyses. It does not identify a tested contrast, an estimate, a standard error, a confidence interval, or a significance test. Descriptive counts can still be reported, but they are not a substitute for a formal comparison. In particular, comparing counts without a defined analysis does not account for group size or uncertainty.

The record includes a sample-size planning description based on a normal approximation, a two-sided significance level, equal allocation, and fractions of an observed effect. That description characterizes planning illustrations, not the trial's original design rationale and not observed power. The numerical planning results and the trial's own sample-size justification are not reported in the registry record. Sample-size illustrations, when reported, are prospective planning aids and should not be read as evidence that a study had a particular probability of detecting an effect after the data were observed.

What can the safety summaries establish?

Adverse-event counts describe what was recorded under the study's collection process and follow-up timeframe. They do not automatically establish causation. The TEAE definition includes medical occurrences without requiring a treatment relationship, and the available aggregate counts do not provide event-level descriptions, severity distributions, durations, or investigator attribution. The serious-event summary separately reports serious events and deaths; those categories should not be conflated with the broader count of participants with any TEAE.

Multiplicity is a general concern when several outcomes, groups, timepoints, or comparisons are tested, because repeated testing can increase the chance of a nominally positive result. The registry lists one primary safety outcome and five secondary pharmacokinetic outcomes, but it does not report an analysis plan or a multiplicity procedure. Without the planned hypotheses and analyses, it is not possible to assess how multiplicity was addressed. Likewise, the registry record does not report a missing-data approach, an interim-analysis plan, or a model for estimating treatment effects. None should be inferred from the design label or the outcome list.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Placebo-Low Dose", "Placebo-High Dose", "Pooled Placebo", "FX-322 Low Dose", "FX-322 High Dose")
n      <- c(4, 4, 8, 7, 8)
events <- c(2, 3, 5, 6, 7)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Placebo-Low Dose  4  2  50.0  6.8  93.2  15.0  85.0  14.7  85.3
ARM  Placebo-High Dose  4  3  75.0  19.4  99.4  30.1  95.4  28.4  94.7
ARM  Pooled Placebo  8  5  62.5  24.5  91.5  30.6  86.3  29.9  86.3
ARM  FX-322 Low Dose  7  6  85.7  42.1  99.6  48.7  97.4  47.3  96.8
ARM  FX-322 High Dose  8  7  87.5  47.3  99.7  52.9  97.8  51.8  97.2

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies the number of participants with TEAEs as the primary outcome and lists five secondary outcomes: Cmax, Tmax, AUClast, t1/2, and CL/F. It reports no analyses. A statistical analysis plan, including any planned contrasts, model choices, or multiplicity adjustment, is not reported in the registry record. Because the secondary outcomes are listed without posted results, their contribution to the study's conclusions cannot be assessed from this record.

Multiplicity refers, in general, to the interpretive problem created when many outcomes or hypotheses are examined. Repeated testing can increase the chance of a result that appears notable under a single-test threshold even when no corresponding effect exists. Adjustments or prespecified outcome hierarchies can address aspects of that issue, but the registry record does not state whether either approach was planned or used. It would be inappropriate to assume a correction, or to assume that no correction was used, beyond noting that the plan is not reported.

The Safety Analysis Set is defined as all participants exposed to study drug, analyzed according to actual treatment received regardless of randomized treatment. This describes the population for the primary safety outcome. The record does not report a missing-data method, the amount or pattern of missing outcome data, or whether participants with incomplete follow-up were handled in a particular way. It also does not report an intention-to-treat analysis population for this endpoint or explain how the analysis population related to randomization.

Interim analyses, stopping rules, and procedures for handling protocol deviations are not reported in the registry record. These omissions limit assessment of how the analysis was planned and how fully the reported groups represent the randomized study population. They do not establish that such procedures were absent; they mean that the registry record does not describe them.

12. 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.

Most frequent non-serious adverse event terms

The serious adverse-event summary reports zero affected participants in each listed group: Placebo-Low Dose, Placebo-High Dose, pooled placebo, FX-322 Low Dose, and FX-322 High Dose. It also reports zero deaths in each group. The number at risk for serious adverse events is listed as 4, 4, 8, 7, and 8 for those groups, respectively. The pooled placebo entry summarizes the placebo cohorts and should not be counted as an additional independent group.

These serious-event figures are separate from the broader TEAE outcome. The registry reports participants with TEAEs in every group, while reporting no serious adverse events or deaths. A TEAE does not have to be serious and does not have to be judged related to treatment. Thus, the two summaries address different categories of safety observations.

Zero reported serious events in these groups means none were recorded in the registry results for this study; it does not prove that the risk is zero. The group sizes and study follow-up limit how much can be inferred about uncommon events or safety in populations beyond the participants studied. The registry does not provide event-level descriptions for serious adverse events, and it lists no serious-event terms. These counts should be interpreted as a record of observed safety events, not as a causal comparison between FX-322 and placebo.

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

The primary result describes the number of participants with at least one TEAE in each posted safety group. It is a direct summary of recorded events during the stated period from baseline through Day 90. The counts show that TEAEs were recorded in both placebo cohorts and both FX-322 dose cohorts. The registry also reports no serious adverse events and no deaths in the listed groups.

These observations do not, by themselves, answer whether FX-322 caused the events, whether event risk differed between treatment groups, or whether one dose had a different safety profile from the other. The TEAE definition does not require a causal relationship, and the registry reports no inferential analysis of the primary outcome. Without a reported treatment contrast and uncertainty estimate, apparent differences among group counts cannot be interpreted as statistically established differences. They also cannot be used to determine whether an observed pattern is larger than would be expected from chance variation.

The results do not establish efficacy or a change in hearing. The primary outcome is a safety count, and the registry record does not provide results for its listed pharmacokinetic secondary outcomes. No conclusion about those measures or about hearing outcomes can be drawn from the safety counts presented.

The trial offers observations from a randomized, double-blind, placebo-controlled phase 1/2 study of a single intratympanic dose in adults with stable sensorineural hearing loss. Those design features describe the study; they do not remove the limitations of small groups, incomplete reporting of analysis procedures, or the absence of comparative statistical results. The findings are therefore best understood as descriptive safety data from the participants included in the recorded safety analysis, rather than as definitive evidence about treatment effects or risks in other settings.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a randomized design and a reported randomized comparison. Randomization is a design strategy for supporting fair group comparisons, but the registry's primary outcome results are counts by safety cohort, with no listed analysis. Without an estimated contrast and a measure of uncertainty, the record supports description of the observed counts but not a formal conclusion about differences between treatments.

The endpoint also illustrates why the meaning of a count must be kept precise. The primary measure counts participants with any TEAE, rather than total events or event severity. That choice can provide a concise summary of how many participants experienced at least one event, while concealing differences in the number and nature of events within that count. The broader TEAE definition includes events without an established causal relationship, making it important not to translate event occurrence directly into treatment attribution.

The registry identifies a Safety Analysis Set based on exposure and actual treatment received. This is a relevant population definition for safety, and it differs from simply assuming that every participant is analyzed according to randomized assignment. Reporting the population explicitly helps readers understand what the counts represent, while the absence of a reported missing-data approach or analysis plan leaves important aspects of the analysis process unclear.

Finally, the study lists several secondary pharmacokinetic measures but does not report their results in the registry record. This underscores the value of distinguishing an outcome's presence in a registry from the availability of analyzable results. A complete statistical interpretation depends not only on the study design and observed counts, but also on transparent reporting of planned analyses, estimates, uncertainty, and the handling of missing information.

15. 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 limitation for interpreting the primary outcome is that the registry record reports descriptive counts but no inferential comparison. It supplies no treatment-effect estimate, confidence interval, or p-value for a two-arm comparison, and it lists zero analyses. As a result, the data cannot establish whether the observed counts reflect a difference between treatment groups or chance variation.

The safety groups are small, with reported group sizes of 4, 4, 8, 7, and 8, including pooled placebo. Counts from small groups can be imprecise, and the registry does not report uncertainty intervals to show that imprecision. The pooled placebo result is a summary of the two placebo cohorts; its inclusion alongside the separate cohorts should not be mistaken for an independent additional comparison group.

The primary endpoint records whether a participant had at least one TEAE, not the total number of events, their severity, duration, or relationship to treatment. The registry definition includes occurrences that need not be caused by study drug. The record does not provide event-level details that would allow those dimensions to be examined.

The study evaluated a single intratympanic dose at two dose levels in adults with stable sensorineural hearing loss. The available description does not support extrapolation to other populations, dosing schedules, or follow-up periods. The outcome timeframe is baseline through Day 90. Results for the listed secondary pharmacokinetic outcomes, a missing-data strategy, the analysis plan, sample-size justification, and interim procedures are not reported in the registry record. These reporting gaps restrict assessment of the broader statistical evidence.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: FX-322 in Sensorineural Hearing Loss — NCT03616223.
• Registry record last updated 2022-11-14; status last verified 2022-10.
• Results first posted 2022-11-14.
• 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.

19. Record Summary

The registry record describes NCT03616223, titled FX-322 in Sensorineural Hearing Loss. It is a completed phase 1/2 randomized, double-blind, placebo-controlled, parallel-group study of single-dose FX-322 at two dose levels, administered by intratympanic injection to adults with stable sensorineural hearing loss. The enrollment was 23, and the sponsor was Frequency Therapeutics.

The primary outcome was the number of participants with TEAEs from baseline through Day 90. The posted safety results report 2 participants in Placebo-Low Dose, 3 in Placebo-High Dose, 5 in pooled placebo, 6 in FX-322 Low Dose, and 7 in FX-322 High Dose. The record reports zero serious adverse events and zero deaths in each listed group.

The record lists Cmax, Tmax, AUClast, t1/2, and CL/F as secondary outcomes but does not report their results. It also reports no analyses for the primary outcome. The study started on 2018-07-03 and reached primary completion on 2018-12-18.