Galcanezumab for Vestibular Migraine: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Galcanezumab for Vestibular Migraine (NCT04417361), a randomized phase 2 study. The primary outcome is Change in VM-PATHI (Vestibular Migraine-Patient Assessment Tool and Handicap Inventory) Score From Baseline to Month 4.

2. Clinical Question

The clinical question is framed around a disease-specific patient-reported score rather than a laboratory measure or a clinician-rated diagnosis. VM-PATHI is described in the registry record as an outcome developed for vestibular migraine, with scores from 0 to 100 and higher scores indicating greater disease-related suffering. The primary comparison therefore concerns the difference in average change between the randomized groups over the treatment period.

This is a pilot trial, so the comparison is informative about the observed data and the uncertainty around them, but it does not by itself settle the size or reliability of any treatment effect. The registry record describes the study as randomized, quadruple-masked, and parallel-group. Those design features are relevant to how the outcome comparison should be interpreted, but the record does not report details such as the exact masking roles or the full eligibility criteria. Results should be read as evidence from this study population and period, not as a definitive estimate applicable to every person with vestibular migraine.

3. Trial Design

The registry record identifies NCT04417361 as a Phase 2 pilot trial titled “Galcanezumab for Vestibular Migraine.” The sponsor is the University of California, San Francisco. The study is listed as randomized, quadruple-masked, and parallel-group, with a planned enrollment of 40. Its recorded start date is 2020-09-18, its primary completion date is 2023-09-29, and its status is completed.

The trial compared galcanezumab with placebo. The treatment descriptions specify subcutaneous injections in both arms, beginning with a loading dose at month 1 and followed by doses at month 2 and month 3. The galcanezumab description states that the loading dose consists of two injections totaling 240 mg, followed by 120 mg at each later administration. The placebo description gives the corresponding schedule for placebo. The descriptions in the registry record end mid-sentence, so any administration details beyond the text recorded there are not reported in the registry record.

The primary outcome is the change in VM-PATHI score from baseline at month 1 to after treatment at month 4. The registry record also lists secondary measures involving definitive dizzy days, response rates based on reductions in dizzy days, Dizziness Handicap Inventory scores, and PROMIS Global Health scores. The posted outcome results include numerical comparisons for definitive dizzy days and Dizziness Handicap Inventory score. Numerical results for the other listed secondary outcomes are not reported in the registry record.

The arm-level primary outcome summaries include 17 participants in the galcanezumab arm and 21 in the placebo arm. These outcome counts differ from the safety denominators reported for adverse events. The registry record does not describe the analysis population or explain the handling of missing outcome data. It also does not report the trial's original sample-size justification or its planned statistical analysis in enough detail to establish whether the posted summaries follow a prespecified analysis plan.

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.

Overall Study

Reasons for not completing this period:

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 Change in VM-PATHI (Vestibular Migraine-Patient Assessment Tool and Handicap Inventory) Score From Baseline to Month 4, measured over Change between baseline (month 1) and after treatment (month 4).

The primary endpoint is change in VM-PATHI score from baseline at month 1 to after treatment at month 4. VM-PATHI is described as a patient-reported outcome developed and validated for vestibular migraine. The registry record says it is highly reliable and valid, responsive to treatment changes, and the only disease-specific outcome measure for vestibular migraine at the time of the record. Those features explain why it was selected to capture patients’ experience of disease-related burden.

Scores range from 0 to 100, with higher values indicating higher disease-related suffering. A negative change therefore represents a lower score at follow-up than at baseline. The primary summaries report mean changes and standard deviations for each randomized arm, followed by a mean difference comparing galcanezumab with placebo. This answers a group-level question: whether average change differed between the trial arms. It does not describe every participant’s experience, and a mean difference alone does not show how outcomes were distributed within either arm.

The endpoint is patient-reported, so its interpretation depends on the instrument and the way it was administered. The registry record characterizes the measure as reliable, valid, and responsive, but does not give a threshold for a change that patients would consider important. Consequently, the numerical size of the observed difference can be described, but its clinical importance cannot be established from the registry information alone.

7. Results Posted in the Registry

• Galcanezumab: mean -14.80 versus -5.10 on control; difference -9.70 (95% CI -20.35 to 0.95), standardized effect d = -0.58; z-test p = 0.074.

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.

Change in Number of Definitive Dizzy Days for Participants Measured Daily From Baseline to Month 4 Via Text Message

• 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:
  • Galcanezumab: mean -11.30 versus -5.60 on control; difference -5.70 (95% CI -10.51 to -0.89), standardized effect d = -0.75; z-test p = 0.020.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Galcanezumab than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change in Dizziness Handicap Inventory Score From Baseline to Month 4

• 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:
  • Galcanezumab: mean -22.00 versus -8.30 on control; difference -13.70 (95% CI -24.90 to -2.50), standardized effect d = -0.80; z-test p = 0.016.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Galcanezumab than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcome findings broadly align in direction with the primary arm means: the galcanezumab group had more negative average changes for the two secondary outcomes with numerical results. That directional consistency can be considered alongside the primary comparison, but it does not remove the uncertainty in the primary estimate or establish that all outcome domains changed in the same way.

The secondary measures cover different aspects of vestibular migraine experience. Definitive dizzy days capture symptom-day frequency, while the Dizziness Handicap Inventory addresses reported handicap. The registry also lists response rates based on reductions in definitive dizzy days and PROMIS Global Health scores. Numerical results for those other listed outcomes are not reported in the registry record. As a result, the secondary evidence is incomplete across the full set of registered measures.

Secondary results generally carry less weight than the primary comparison when their testing strategy is not fully reported. The record does not describe a multiplicity adjustment, nor does it identify which secondary tests were prespecified as confirmatory. Examining several outcomes can increase the chance that some results appear notable by chance, even when no individual outcome comparison is misleading. The unadjusted p-values therefore need to be interpreted as exploratory signals rather than as a complete confirmatory analysis.

The secondary outcomes may still help characterize the pattern of observations and inform future study design. They cannot substitute for a well-powered primary comparison, and they do not demonstrate that any particular change is important to participants. The registry record does not provide minimally important thresholds for these measures or enough detail about missingness and analysis populations to assess how robust the secondary findings are.

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

• Change in Number of Definitive Dizzy Days for Participants Measured Daily From Baseline to Month 4 Via Text Message
• Change in Response Rates as Defined by Percentage Reduction in Definitive Dizzy Days Via Text Message From Baseline to Month 4
• Change in Dizziness Handicap Inventory Score From Baseline to Month 4
• Change in Patient-Reported Outcomes Measurement Information System Short Form (PROMIS SF) v1.2- Global Health Scores

9. Statistical Interpretation

10. Statistical Methods Explained

The posted comparisons are based on continuous outcomes summarized by arm means and standard deviations. The arm summaries describe average change and the variability of individual changes around each arm’s mean. The comparison is a mean difference, expressed as the galcanezumab mean minus the placebo mean. A negative difference indicates a more negative average change in the galcanezumab arm. For VM-PATHI, negative change corresponds to a lower score, and the registry record defines higher scores as greater disease-related suffering.

What does an unadjusted mean difference show?

A mean difference reduces the two group averages to one contrast on the outcome’s original scale. It helps answer whether the average change differed between the randomized groups. It does not convey the full distribution of responses, the proportion of participants who improved, or whether a particular change matters to an individual. The reported recalculations use the posted arm-level means, standard deviations, and participant counts. They are simple unadjusted comparisons rather than estimates adjusted for baseline covariates or other factors.

The registry record lists the primary outcome as a mean with standard deviation and gives arm-level outcome counts of 17 and 21. The recalculated comparison uses those summaries. Since the record does not provide participant-level data, covariate-adjusted estimates, or details of the sponsor's analysis, the recalculation cannot reproduce an analysis that might have used other methods or data. No discrepancy is flagged between the posted summaries and the recalculated comparison.

What does the confidence interval contribute?

A confidence interval expresses the range of effect estimates that are reasonably compatible with the observed data under the method used to construct it. A narrow interval indicates greater precision than a wide interval, while an interval spanning zero leaves uncertainty about the direction of the underlying average difference. It is not a range containing every participant's response, and it does not assign a probability to a particular effect value. The posted primary interval crosses zero, while the secondary intervals for the outcomes with numerical comparisons do not.

Confidence intervals and p-values are related ways of describing uncertainty, but they are not interchangeable with clinical importance. A p-value reflects the compatibility of the data with a specified no-difference model, conditional on the analysis assumptions. It does not measure the magnitude or importance of a difference. The registry record does not provide a minimally important difference for VM-PATHI, so statistical evidence cannot be translated directly into a threshold for patient importance.

Why can over-dispersion matter?

In general, over-dispersion means that outcome variability is greater than a model assumes. When a method assumes less variability than the data contain, standard errors may be too small and intervals too narrow, making the evidence appear more precise than it is. The primary and posted secondary outcomes are continuous summaries with standard deviations, and the recalculated comparisons use the reported variability rather than a count-based model. The registry record does not report a separate over-dispersion assessment or a modeling strategy that would allow its handling to be evaluated. This general point is especially relevant when considering repeated measurements or outcome counts, but it should not be read as evidence that over-dispersion was present in this trial.

How should the p-values be read?

The primary p-value is unadjusted, as are the recalculated secondary p-values. An unadjusted p-value does not account for the possibility that examining multiple outcomes increases the chance of seeing at least one apparently unusual result. The registry lists several secondary outcomes, but the statistical plan and any multiplicity adjustment are not reported in the registry record. The p-values should therefore be understood as outcome-specific, unadjusted summaries rather than as results from a reported family-wide testing strategy.

The sample-size figures use a different purpose from the trial's outcome analysis. They are planning illustrations calculated from observed effects, under a two-sided significance level of 0.05, equal allocation, and a normal approximation. The effect to detect is set to a stated fraction of the observed effect. Such calculations can illustrate how precision and power depend on effect size and enrollment, but they do not establish what assumptions were used when the trial was designed. The original design assumptions are not reported in the registry record.

Finally, the registry record does not report the trial's analysis population, missing-data method, interim analyses, or full statistical analysis plan. It is therefore not possible to determine from the record whether all randomized participants were included in each outcome analysis, how incomplete follow-up was handled, or whether any analyses were prespecified. Those omissions limit how completely the posted summary statistics can be evaluated.

11. Confidence Intervals and Precision

The primary estimate is a mean difference of -9.7 VM-PATHI points for galcanezumab compared with placebo. Its interval extends from -20.35 to a small positive upper bound and crosses zero. Thus, the data are compatible with a larger negative difference, a difference near zero, or a small difference in the positive direction. The interval expresses uncertainty around the average comparison; it does not imply that individual participant changes lie within those limits.

The interval is wide enough to leave substantial uncertainty about the size and direction of the underlying difference. Its lower bound is considerably more negative than the point estimate, while the upper bound is on the positive side of zero. The primary p-value of 0.074 is consistent with the interval's inclusion of zero, but neither statistic identifies a single true effect. The record does not report a threshold for a clinically important VM-PATHI change, so the interval cannot be judged against such a threshold using the registry information.

Precision is influenced by the amount of outcome information and the variability in the observed changes. The primary arm standard deviations are 16.1 and 17.3, with outcome counts of 17 and 21. Those summaries indicate appreciable variation around the arm means in this pilot sample. The record does not report missing-data handling or the analysis population, so it is not possible to determine whether the available outcome counts represent all randomized participants or how incomplete observations may have affected precision.

The secondary comparisons have intervals that do not cross zero, but they remain subject to the same general limitations of small-sample estimation and unadjusted testing. Their apparent precision should not be treated as confirmation of the primary result, particularly because multiplicity handling is not reported. Confidence intervals are most useful when read alongside the outcome scale, the point estimate, the study design, and the limits of the record, rather than as a stand-alone verdict.

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 planning figures are expressed as participants per arm, not as total events. The sample-size assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set at 100%, 75%, or 50% of the observed effect. These are planning illustrations based on the observed comparison, not the trial's original design rationale; that original rationale is not reported in the registry record.

The 80% power column gives the estimated number of participants per arm for a design with an 80% chance of detecting the specified effect under the stated assumptions, if that effect is the true one and the model assumptions hold. The 90% power column makes the same kind of calculation for a higher chance of detection. These are prospective design quantities, not summaries of how likely the completed trial was to find a result.

For the primary comparison, the figures range from 47 participants per arm for planning around 100% of the observed effect at 80% power, to 188 participants per arm for planning around 50% of the observed effect at 80% power. At 90% power, the corresponding planning figures are 63 and 252 participants per arm. The figures for 75% of the observed effect fall between those entries. This pattern reflects a general relationship: smaller effects are harder to distinguish from random variation, so planning for smaller effects requires more participants. The power calculations are not observed power; they are illustrations for future planning under the listed assumptions.

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 = -9.700; pooled standard deviation σ = 16.777.
2. n = 2 × (1.96 + 0.842)² × 16.777² / -9.700² = 47.0, rounded up to 47 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 <- -9.7                      # observed difference in means
sigma <- 16.7772663645383                     # 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(4417361)
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 = 47 (80% power), 63 (90% power)
 75% of observed effect: n per arm = 84 (80% power), 112 (90% power)
 50% of observed effect: n per arm = 188 (80% power), 252 (90% power)
power.t.test: 47.9 
Simulated power at n = 47 per arm: 0.792 (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. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary outcome and several secondary outcomes, but it does not report how the statistical plan handled multiple comparisons. No multiplicity adjustment is described. This matters because evaluating multiple outcomes can increase the chance of finding one or more apparently unusual results even when the underlying effects are absent. The recalculated p-values are unadjusted and should be read as individual comparisons, not as evidence from a reported family-wise testing procedure.

The record also does not report an analysis population, such as whether the primary analysis included all randomized participants or only participants with available outcome data. The primary outcome summaries contain 17 participants in the galcanezumab arm and 21 in the placebo arm, while the adverse-event risk groups contain 18 and 22. These different counts are reported for different purposes; the record does not explain the difference or state how it arose.

Missing-data procedures are not reported in the registry record. It is not possible to tell whether outcomes were imputed, whether incomplete follow-up was handled through a particular model, or whether participants with missing measurements were excluded from an analysis. The record also does not give a sensitivity analysis showing how alternative missing-data assumptions might affect the estimated comparison.

The trial's full statistical analysis plan, interim analyses, and original sample-size justification are not reported in the registry record. Without those details, it is not possible to check whether the outcome choices, analysis methods, or stopping and monitoring decisions were prespecified. These omissions do not change the numerical summaries, but they constrain assessment of confirmatory intent and the potential influence of analytic choices. They also mean that the recalculated unadjusted comparisons should be treated as descriptive statistical evidence rather than as a complete account of the trial's planned inferential strategy.

15. 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 registry record reports serious adverse events for each arm using a safety group at risk of 18 for galcanezumab and 22 for placebo. It reports zero participants affected by serious adverse events in each group and zero deaths in each group. These are the posted counts; they do not establish that no serious events could occur with either treatment.

For other adverse events, the record reports 4 affected participants in the galcanezumab group and 8 in the placebo group, using the same respective risk groups. The record does not list individual serious adverse-event terms. These counts describe what was recorded in this trial and should not be converted into a broader safety conclusion without considering the study's size, follow-up, event definitions, and collection procedures.

The safety denominators differ from the primary outcome counts. The registry record does not explain the difference, and the groups should not be combined or treated as having identical analysis populations. Adverse-event counts are descriptive; the record does not provide a formal comparative safety analysis or enough detail to determine how events were assessed, attributed, or monitored.

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

The posted primary data show lower mean VM-PATHI scores at month 4 relative to baseline in both randomized arms, with a more negative average change in the galcanezumab arm. The recalculated mean difference is -9.7, and the interval crosses zero. This means the point estimate favors a larger score reduction in the galcanezumab arm, but the data leave uncertainty about the true between-arm difference. The primary result should not be described as definitive evidence for or against a treatment effect.

The direction of the change has a clear scale-based interpretation: higher VM-PATHI scores indicate greater disease-related suffering, so a negative change represents a lower score. However, the registry record does not identify a clinically important threshold for this measure. It is therefore not possible to infer from the numerical difference alone whether participants would regard the observed change as important.

The trial's randomized, masked design is a strength for comparing groups, but the study is described as a pilot and its outcome counts are limited. The registry record also does not report the full analysis plan, missing-data handling, or multiplicity strategy. Those gaps make it difficult to assess the degree to which the numerical comparisons reflect prespecified analyses and how sensitive they might be to incomplete follow-up or analytic choices.

The secondary outcomes with posted numbers show a similar direction in their arm means, but they are unadjusted and multiplicity handling is not reported. The other registered secondary outcomes do not have numerical results in the record. The secondary findings can contribute to the overall description of the trial, but they should not be treated as independent proof of the primary pattern.

These results apply to the participants and follow-up represented in this pilot trial. They do not establish how the findings would generalize to other populations, longer periods, or different clinical settings. The data describe an observed randomized comparison, with uncertainty; they do not support medical advice or a broad claim that the treatment does or does not work.

17. Why This Trial Matters Statistically

This trial is statistically useful because it evaluates a disease-specific patient-reported outcome in a randomized, masked comparison. VM-PATHI is described as a recently developed and validated measure for vestibular migraine and as responsive to treatment changes. Using such an outcome makes the central comparison directly relevant to the condition's reported burden, while also creating a need to understand the score's scale and the meaning of changes on it.

The primary result illustrates why an estimate should be read together with its uncertainty. The arm means favor a larger average decrease with galcanezumab, but the mean-difference interval crosses zero. A point estimate by itself could overstate certainty; a p-value alone could obscure the range of plausible differences. Considering the estimate, interval, outcome direction, and pilot context gives a more complete statistical interpretation.

The study also illustrates the distinction between a registered outcome and a fully reported analysis plan. The registry lists multiple secondary measures, but numerical results are available for only some of them, and multiplicity handling is not reported. That limits the weight that can be placed on apparently favorable unadjusted secondary comparisons. Clear reporting of analysis populations, missing-data methods, and prespecified testing strategies would make future evaluations easier to assess.

Finally, the planning illustrations show how future study size depends on the effect a study aims to detect. Planning for a smaller fraction of an observed effect requires more participants per arm under the stated assumptions. These figures are not evidence about the trial's original design choices, but they demonstrate why pilot estimates and their uncertainty matter when planning subsequent research.

18. 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 study is explicitly described as a pilot trial, and the primary outcome counts are limited. Estimates from a limited sample may be imprecise, as reflected by the primary interval crossing zero and spanning a range of possible differences. The sample-size illustrations are based on the observed effect, so they should not be treated as reliable proof that a particular future enrollment would reproduce that effect.

The registry record does not report full eligibility criteria, detailed participant characteristics, or the number and reasons for withdrawals. It is therefore difficult to assess how representative the analyzed participants were or whether departures from follow-up could have influenced the results. The posted outcome counts differ from the safety denominators, but the record does not explain why.

Methods for missing outcomes, the analysis population, and any imputation or sensitivity analyses are not reported in the registry record. The full statistical analysis plan, original sample-size justification, and interim-analysis procedures are also not reported. Without those details, readers cannot verify whether the posted analyses match prespecified methods or assess the robustness of results to alternative assumptions.

Multiplicity handling is not reported despite the listing of several secondary outcomes. The unadjusted secondary comparisons therefore warrant caution, and numerical results for some registered secondary measures are absent. The record also provides no threshold for a clinically important change in VM-PATHI or the other measures, limiting interpretation of the observed magnitude in patient-relevant terms.

Finally, the intervention descriptions in the registry end mid-sentence, leaving some administration details unreported in the registry record. The posted safety information is limited to counts, without detailed event terms or a formal comparative safety analysis. These reporting limitations constrain interpretation; they do not, by themselves, indicate that any specific bias or safety issue occurred.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Galcanezumab for Vestibular Migraine — NCT04417361.
• Registry record last updated 2024-12-10; status last verified 2024-11.
• Results first posted 2024-12-10.
• 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.

22. Record Summary

NCT04417361 is a completed Phase 2 randomized, quadruple-masked, parallel-group pilot trial sponsored by the University of California, San Francisco. It compared subcutaneous galcanezumab with placebo for vestibular migraine. The registry record gives an enrollment of 40, a start date of 2020-09-18, and a primary completion date of 2023-09-29.

The primary outcome was change in VM-PATHI score from baseline at month 1 to month 4. Mean change was -14.8 with galcanezumab and -5.1 with placebo; the recalculated unadjusted mean difference was -9.7, with an interval crossing zero and an unadjusted p-value of 0.074. The primary comparison is therefore uncertain rather than definitive. Some secondary numerical comparisons favor a more negative average change with galcanezumab, but they are unadjusted and multiplicity handling is not reported.

The record reports zero serious adverse events and zero deaths in both safety groups, with other adverse events affecting 4 participants in the galcanezumab group and 8 in the placebo group. Analysis populations, missing-data methods, the full statistical plan, and the original sample-size rationale are not reported in the registry record.