Randomized, Placebo Controlled Study Of The Efficacy And Safety Of PF-02545920 In Subjects With Huntington's Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Randomized, Placebo Controlled Study Of The Efficacy And Safety Of PF-02545920 In Subjects With Huntington's Disease (NCT02197130), a randomized phase 2 study. The primary outcome is Change From Baseline in the Total Motor Score (TMS) Assessment of the Unified Huntington Disease Rating Scale (UHDRS) After 26 Weeks of Treatment..

2. Clinical Question

3. Trial Design

This was a phase 2, randomized, placebo-controlled, parallel-group trial. The registry labels masking as quadruple, while the study summary describes the trial as double blind. The record does not explain the difference between those descriptions. It lists a planned study duration of 26 weeks and three groups: PF-02545920 20 mg BID, PF-02545920 5 mg BID, and matching placebo BID.

The registry lists enrollment as 272. Its study summary separately says that approximately 260 subjects were planned to be randomized. These are not interchangeable descriptions: the first is the listed enrollment figure, while the second is the approximate plan stated in the summary. The record does not explain the distinction.

The listed start was 2014-09, primary completion was 2016-09, and status is completed. The primary outcome was change from baseline in UHDRS Total Motor Score after 26 weeks. The registry also lists secondary outcomes covering clinical ratings and safety, including adverse events, serious adverse events, laboratory abnormalities, and vital-sign criteria. Detailed registry information about allocation procedures, concealment, and the full analysis protocol is not reported in the registry record.

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: A total of 272 subjects (133 males and 139 females) were randomized and assigned study treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants who have been randomized and have taken at least one dose of PF-02545920 or placebo. Participants without post-dose measurements did not contribute to the analysis, except in the description of the baseline values.

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 From Baseline in the Total Motor Score (TMS) Assessment of the Unified Huntington Disease Rating Scale (UHDRS) After 26 Weeks of Treatment., measured over Baseline, Week 26.

The primary endpoint was change from baseline in the Total Motor Score (TMS) of the Unified Huntington Disease Rating Scale (UHDRS) after 26 weeks of treatment. TMS is a continuous clinical rating of motor features of Huntington's disease. The registry describes standardized ratings of oculomotor function, dysarthria, chorea, dystonia, gait, and postural stability. Some motor features are rated separately across body areas, and eye movements receive horizontal and vertical grades.

The total is formed from the individual motor sub-items, each rated from 0 to 4. The stated scale range is 0-124, with higher scores indicating more severe motor impairment. A change from baseline expresses how the score moved over the treatment period rather than describing the score at a single visit. Comparing average changes between each dose and placebo is intended to assess whether the groups' observed trajectories differed on this motor measure.

TMS is used because the study's stated focus was motor impairment and the scale provides a standardized assessment of motor features. It does not, by itself, describe every aspect of Huntington's disease: the registry notes that the broader UHDRS includes motor, cognitive, behavioral, and functional components. The posted primary outcome concerns the motor component only.

7. Results Posted in the Registry

• PF-02545920 20 mg BID: mean 0.40 versus -1.40 on control; difference 1.80 (95% CI -0.84 to 4.44), standardized effect d = 0.24; z-test p = 0.182.
• PF-02545920 5 mg BID: mean -0.80 versus -1.40 on control; difference 0.60 (95% CI -1.55 to 2.75), standardized effect d = 0.09; z-test p = 0.584.

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.

Number of Participants With Laboratory Test Abnormalities (Without Regard to Baseline Abnormalities)

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • PF-02545920 20 mg BID: 54.7% (47/86) versus 54.5% (48/88) on control; risk difference 0.1 percentage points (95% CI -14.7 to 14.9), risk ratio 1.00 (0.76–1.31); unadjusted two-proportion z-test p = 0.989.
  • PF-02545920 5 mg BID: 48.4% (46/95) versus 54.5% (48/88) on control; risk difference -6.1 percentage points (95% CI -20.6 to 8.3), risk ratio 0.89 (0.67–1.18); unadjusted two-proportion z-test p = 0.408.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between PF-02545920 20 mg BID and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between PF-02545920 5 mg BID and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Laboratory Test Abnormalities (With Normal Baseline)

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • PF-02545920 20 mg BID: 46.5% (40/86) versus 46.6% (41/88) on control; risk difference -0.1 percentage points (95% CI -14.9 to 14.7), risk ratio 1.00 (0.73–1.37); unadjusted two-proportion z-test p = 0.992.
  • PF-02545920 5 mg BID: 37.9% (36/95) versus 46.6% (41/88) on control; risk difference -8.7 percentage points (95% CI -23.0 to 5.6), risk ratio 0.81 (0.58–1.14); unadjusted two-proportion z-test p = 0.234.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between PF-02545920 20 mg BID and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between PF-02545920 5 mg BID and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists secondary outcomes spanning clinical ratings, adverse events, serious adverse events, laboratory abnormalities, and vital-sign criteria. It reports 14 secondary outcomes, but the level of numerical detail available varies across them. Some outcomes describe counts of participants meeting criteria; others concern clinical assessments. The record does not provide a complete, comparable set of estimates and uncertainty measures across every listed secondary endpoint.

The available secondary results should be read as supplementary to the primary TMS comparison, not as a substitute for it. They address different questions and may have different denominators, timeframes, and outcome definitions. A finding on a laboratory or safety measure would not directly establish a difference on motor impairment, just as the primary motor result does not summarize all safety outcomes.

Unadjusted secondary results carry less weight when many endpoints are examined because the chance of at least one apparently unusual result can increase with the number of tests. Appropriate interpretation depends on whether a multiplicity strategy was planned and how it was applied. That strategy is not reported in the registry record. The record also does not report a complete statistical analysis plan for the secondary outcomes.

Consequently, the secondary outcomes can give context about what was monitored, but the registry record does not support a unified conclusion across all of them. Their role is descriptive unless the study's testing plan and complete analysis details are available. The primary endpoint remains the designated main question, while secondary findings should be interpreted with their scope and statistical limitations in view.

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

• Number of Participants That Met White Blood Count (WBC) and Absolute Neutrophil Count (ANC) Stopping Criteria
• Number of Participants With Adverse Events
• Number of Participants With Serious Adverse Events
• Number of Participants With Laboratory Test Abnormalities (Without Regard to Baseline Abnormalities)
• Number of Participants With Laboratory Test Abnormalities (With Normal Baseline)
• Number of Participants With Vital Sign Data That Met Criteria for Potential Clinical Concern (Absolute Values)
• Number of Participants With Vital Sign Data That Met Criteria for Potential Clinical Concern (Increase From Baseline)
• Number of Participants With Vital Sign Data That Met Criteria for Potential Clinical Concern (Decrease From Baseline)

9. Statistical Interpretation

10. Statistical Methods Explained

What is a mean difference?

The primary measure is continuous, so each arm's result is summarized by a mean change and a standard deviation. A mean difference compares average change in one arm with average change in another. In the recalculation, the placebo mean is the reference and the estimate is treatment minus placebo. A positive estimate therefore means the treatment arm's average change is numerically higher than the placebo arm's average change; it does not by itself mean better or worse. The scale's direction must also be considered: higher TMS scores indicate more severe motor impairment.

The posted recalculations use arm-level summary statistics and make no adjustment for other variables or repeated observations. They are simple, unadjusted re-calculations, not a replacement for the sponsor's analysis. The reported recalculated estimates are 1.8 for 20 mg BID and 0.6 for 5 mg BID compared with placebo.

What does a confidence interval express?

A confidence interval represents uncertainty around an estimate under the statistical method used. A narrower interval is more precise; a wider one allows a broader range of plausible values. When an interval includes zero for a mean difference, the data are compatible with no average difference under that analysis, as well as with values on either side of zero. This is not proof that the true difference is exactly zero. For the primary endpoint, the recalculated intervals extend across zero for both dose comparisons.

The registry's MMRM results report 90% confidence intervals, while the recalculation intervals are derived from posted summary statistics. The registry does not state the confidence level for the recalculated intervals, so it should not be inferred from the sponsor's 90% intervals. A confidence interval and a p-value convey related but different information: the interval indicates a range of estimates compatible with the data and method, while the p-value measures how inconsistent the data are with a specified null hypothesis under that method.

Why are the reported estimates not the same?

The registry reports MMRM analyses, giving net mean differences of 1.52 and -0.35 for the dose comparisons. A mixed model for repeated measures can use repeated outcome observations and model their relationship over time. In general, such a model can account for correlations among measurements from the same participant and can include specified covariates or time effects. The precise model specification, covariates, covariance structure, and handling of missing outcomes are not reported in the registry record. Those details should not be assumed.

The recalculation instead compares the posted summary means using an unadjusted method. It does not reproduce the MMRM. Differences in modeling and in the information used can yield different estimates and intervals. The registry record does not mark a discrepancy between the analyses, and the MMRM results remain the sponsor's reported analyses.

What do the p-values say?

The recalculated unadjusted p-values are 0.182 for 20 mg BID and 0.584 for 5 mg BID. The sponsor's reported values are 0.203 and 0.755, respectively. These values do not provide the probability that a treatment works or that the null hypothesis is true. They describe how unusual the data would be under a specified null model and analysis. Interpretation depends on the model, endpoint, and testing plan; the registry's multiplicity plan is not reported.

A non-small p-value does not establish that groups are equivalent, and it does not rule out effects that the data estimate imprecisely. The confidence intervals are useful alongside p-values because they show the range and direction of estimates compatible with each analysis.

Why can over-dispersion matter?

General statistical explanation: for count or binary outcomes, a model that assumes less variability than the data actually contain can produce overly narrow intervals and overly optimistic tests. Over-dispersion means that outcomes vary more than the assumed model allows. The primary endpoint is continuous and is reported as a mean with standard deviation, so over-dispersion is not the central feature of its mean-difference analysis. For binary secondary outcomes, the suitable method depends on outcome definitions and assumptions; the recalculated summaries should not be mistaken for the sponsor's full analysis.

Overall, the central distinction is between the sponsor's reported repeated-measures model and an unadjusted calculation from arm summaries. Each answers a related but not necessarily identical statistical question. Model details beyond the name MMRM are not reported in the registry record.

11. Confidence Intervals and Precision

Precision is reflected in the spread of plausible values around an estimate, not just in the estimate itself. The recalculated mean difference for 20 mg BID versus placebo is 1.8, with an interval from -0.843 to 4.443. For 5 mg BID versus placebo, the mean difference is 0.6, with an interval from -1.545 to 2.745. Each interval includes zero and extends to values on both sides of zero. The posted recalculations therefore leave uncertainty about the direction and magnitude of a group difference.

The sponsor's MMRM analysis reports 90% confidence intervals from -0.45 to 3.49 for the 20 mg comparison and from -2.20 to 1.50 for the 5 mg comparison. Those intervals also include zero. The recalculated and sponsor intervals differ because they come from different methods and estimates; their endpoints should not be combined or treated as though they were generated by the same analysis.

In general, an interval expresses uncertainty conditional on the statistical method and assumptions. It does not account automatically for every possible source of bias, nor does it make the range of values equally likely. The registry record does not report a clinically important difference threshold for TMS, so it is not possible to determine from these intervals alone which values would be clinically meaningful. The overall message is limited precision around both comparisons, rather than a precise estimate of no difference.

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.

For this continuous primary outcome, the planning figures are participants per arm. In general, a time-to-event planning display may instead give total events; that is not the quantity used for this primary endpoint. The planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers effects at the stated fraction of the observed effect: 100%, 75%, and 50%. Smaller effects require more participants to detect under the same planning assumptions.

The 80% power column represents the number of participants per arm that the illustration estimates would give an 80% chance of detecting the specified effect under its assumptions. The 90% power column uses a higher target chance of detection and therefore requires more participants per arm for the same effect. These are planning illustrations based on the observed effect, not the original trial's design calculations. The trial's own sample-size assumptions and justification are not reported in the registry record.

The planning figures are not observed power. They should not be read as evidence that the completed study had a particular probability of detecting an effect after the results were known. In addition, planning from an observed effect is sensitive to uncertainty in that effect: a noisy estimate can produce an unstable illustration. The values are best used to see how the assumed effect size and target power influence planning, not as a verdict on the trial's conduct or on whether the result is clinically important.

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 = 1.800; pooled standard deviation σ = 7.562.
2. n = 2 × (1.96 + 0.842)² × 7.562² / 1.800² = 277.1, rounded up to 278 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 <- 1.8                      # observed difference in means
sigma <- 7.56204665649694                     # 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(2197130)
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 = 278 (80% power), 371 (90% power)
 75% of observed effect: n per arm = 493 (80% power), 660 (90% power)
 50% of observed effect: n per arm = 1,109 (80% power), 1,484 (90% power)
power.t.test: 278 
Simulated power at n = 278 per arm: 0.798 (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 own primary analyses use MMRM and report net mean differences of 1.52 for 20 mg BID versus placebo and -0.35 for 5 mg BID versus placebo. The corresponding 90% confidence intervals are -0.45 to 3.49 and -2.20 to 1.50, with p-values of 0.203 and 0.755. Both intervals include zero.

The simple recalculations from the posted arm means and standard deviations give mean differences of 1.8 and 0.6, with unadjusted p-values of 0.182 and 0.584. They do not reproduce the sponsor's model-based estimates. The sponsor's analyses use MMRM, whereas the recalculation is an unadjusted comparison of summary statistics. Differences between the estimates are therefore not, on their own, evidence of a reporting error.

The registry record does not describe the MMRM specification in enough detail to reproduce it. Readers should distinguish the sponsor's prespecified or model-based result, as reported in the record, from the simple recalculation. The recalculation can help illustrate the scale and uncertainty of an unadjusted comparison, but it does not supersede the sponsor's analysis or establish which modeling choices were used. The record does not report further detail about the model's covariates, covariance structure, or missing-data assumptions.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when an analysis evaluates more than one hypothesis, such as several doses, endpoints, time points, or safety outcomes. Even if each test uses a conventional threshold, examining many tests can make at least one apparently notable result more likely by chance. Methods such as hierarchical testing or adjustment can address this, but the registry record does not report whether such a plan was used, what family of outcomes it covered, or whether any adjustment was applied. The reported p-values should therefore be read as the values attached to the analyses, not as proof that multiplicity has been controlled.

The study has a primary TMS outcome and a set of secondary outcomes. The registry summary also describes secondary clinical assessments at specified visits, while the listed safety outcomes cover several types of events and measurements. The record does not report a full testing hierarchy, interim-analysis plan, or a detailed statistical analysis plan. None should be inferred from the number or order of outcomes listed.

The primary analysis population is described as participants who were randomized and took at least one dose. Participants without post-dose measurements did not contribute to the primary analysis, except in the description of baseline values. This does not tell readers how missing post-dose observations were handled within the sponsor's MMRM analysis, or whether sensitivity analyses were conducted. Those details are not reported in the registry record.

In general, missing data can affect estimates when the reasons for missingness relate to outcomes or treatment. A repeated-measures model may use observed measurements under particular assumptions, but the model name alone does not establish that those assumptions are appropriate. The record does not report reasons for missing measurements, the amount of missing outcome data, or the results of analyses designed to test sensitivity to missingness. These omissions limit assessment of how robust the primary result is to incomplete follow-up.

The record identifies an analysis population that excludes participants without post-dose measurements from the primary endpoint analysis. It does not provide enough detail to characterize that analysis as a complete intention-to-treat analysis or to determine how all randomized participants were handled. Population definitions, missing-data assumptions, and multiplicity are important parts of interpreting the reported estimates, but remain incompletely documented in the registry record.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: general physical health deterioration (2.3%), major depression (2.3%), urinary tract infection (1.1%), weight decreased (1.1%), back pain (1.1%).

The serious adverse event figures are reported as participants affected among those at risk in each group. The registry lists 2 affected participants among 95 at risk in the PF-02545920 5 mg BID group, 7 among 88 at risk in the placebo group, and 8 among 87 at risk in the PF-02545920 20 mg BID group. These are descriptive group counts, not adjusted comparisons or proof that treatment caused or prevented an event.

The registry also lists serious-event terms with reported percentages, including general physical health deterioration and major depression at 2.3% each, and urinary tract infection, weight decreased, back pain, and pancreatic carcinoma at 1.1% each. The record does not give enough detail in these summaries to establish comparative risk for each event term. A list of terms should not be treated as a complete causal assessment.

Deaths are not reported in the registry record. The serious adverse event counts should be interpreted alongside the study's duration, population, and reporting definitions. They describe the posted safety data, not a complete evaluation of longer-term safety.

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

The primary result is a comparison of mean change in UHDRS Total Motor Score after 26 weeks. The recalculated mean differences are 1.8 for 20 mg BID versus placebo and 0.6 for 5 mg BID versus placebo. The sponsor's MMRM estimates are 1.52 and -0.35, respectively. The estimates differ by method, and the confidence intervals reported for both approaches include zero.

These results do not provide a precise separation from placebo on the primary motor measure. They also do not prove that the groups are equivalent or that no meaningful difference exists. The intervals allow values on either side of zero, and the registry record does not specify a threshold for a clinically important difference. The statistical results alone cannot resolve clinical importance.

The findings apply to the endpoint, analysis population, and follow-up described in the registry. They do not summarize all disease features, since TMS measures motor impairment rather than the full range of cognitive, behavioral, and functional domains included in the broader UHDRS. They also do not determine longer-term outcomes beyond the stated treatment period.

Safety counts are a separate part of the record. They describe reported participants with serious adverse events and should not be interpreted as causal treatment effects. The record does not provide detailed information about all potential confounding, missing observations, or the full analysis plan. Therefore, conclusions should remain bounded by the posted results and the limitations in reporting.

No medical advice follows from these statistical summaries. The results describe estimates and their uncertainty in this completed phase 2 trial; they do not, by themselves, establish what a treatment will do for an individual or settle broader questions about treatment.

18. Why This Trial Matters Statistically

This trial illustrates why a group mean and its uncertainty should be considered together. The reported arm means are close in scale, but the comparison intervals extend across zero and include estimates in either direction. Reading only the point estimates would hide that uncertainty; reading only a p-value would also leave out the range of compatible effects.

It also illustrates why the analysis method matters. The sponsor reports MMRM estimates, while a simple recalculation from arm summaries produces different mean differences. Neither should be substituted silently for the other. Model-based repeated-measures analyses and unadjusted summary comparisons can use different information and answer related but distinct questions. Transparent reporting of the model specification helps readers understand and reproduce the analysis.

The trial also raises familiar issues in clinical-trial interpretation: how missing post-dose outcomes were handled, which analysis population was used, and whether multiple endpoints were accounted for. These details influence how confidently results can be interpreted. Their absence from the registry record is a reporting limitation, not evidence that a particular method was or was not used.

Finally, planning illustrations based on observed effects show why assumptions about effect size matter. Smaller target effects require larger participant numbers under the stated planning approach. Such illustrations are not a substitute for the original design rationale and are not observed power. The registry record does not report the trial's own sample-size justification.

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 registry record gives a concise description of the primary outcome and analysis population, but important analytical details are not reported. The MMRM is named without its full specification, including covariates, covariance structure, and missing-data assumptions. That limits independent reproduction and makes it difficult to explain precisely why the sponsor's model-based estimates differ from simple recalculations.

The primary analysis excludes participants without post-dose measurements, apart from baseline descriptions. The record does not state how many primary outcome measurements were missing, why they were missing, or whether sensitivity analyses addressed missingness. The listed enrollment and the approximate randomization plan in the summary are both present, but their relationship is not explained.

The registry record also does not report a clinically important TMS threshold, a multiplicity plan, detailed allocation procedures, or the original sample-size justification. Those omissions constrain judgments about clinical importance, control of false-positive findings across endpoints, and the adequacy of the original design. The planning illustrations based on observed effects do not fill that gap.

Follow-up for the primary endpoint is described at 26 weeks. The record does not establish longer-term outcomes. The safety summaries provide serious adverse event counts and selected event terms, but do not offer a complete causal evaluation or a full account of all safety analyses. These limitations are specific to what is documented in the registry record and do not demonstrate that unreported procedures were absent.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Randomized, Placebo Controlled Study Of The Efficacy And Safety Of PF-02545920 In Subjects With Huntington's Disease — NCT02197130.
• Registry record last updated 2017-11-17; status last verified 2017-10.
• Results first posted 2017-11-17.
• 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

NCT02197130 is a completed phase 2 randomized, placebo-controlled, parallel-group study of PF-02545920 in participants with Huntington's disease. It compared 5 mg BID and 20 mg BID with matching placebo, with a 26-week primary endpoint of change from baseline in UHDRS Total Motor Score.

The sponsor's MMRM analyses report net mean differences of 1.52 and -0.35 versus placebo; both 90% confidence intervals include zero. Simple unadjusted recalculations also have intervals that include zero. The registry lists safety and laboratory outcomes, but multiplicity and several analysis details are not reported in the registry record.