This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Amyloid Imaging And Safety Study Of ACC-001 In Subjects With Early Alzheimer's Disease (NCT01227564), a randomized phase 2 study. The primary outcome is Change From Baseline in Brain Fibrillar Beta-Amyloid Protein (Aβ) at Week 104 as Measured by Standard Uptake Value Ratios (SUVRs) Over the Composite Regions of Interest (ROIs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01227564 |
| Phase | Phase 2 |
| Condition | Alzheimer's Disease |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 63 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
People with early Alzheimer's disease. The primary analysis population was the full analysis set: randomized participants who received at least one dose of investigational product. The registry record reports an enrollment of 63, but the arm descriptions do not give fuller eligibility or participant characteristics.
Intervention
ACC-001 with QS-21 adjuvant, studied at ACC-001 doses of 3 μg and 10 μg; QS-21 was 50 μg in both listed combinations.
Comparator
Placebo, identified as phosphate buffered saline (PBS). The trial is described as placebo-controlled and parallel-group.
Primary question
What change from baseline in brain fibrillar beta-amyloid, measured by florbetapir F18 PET and expressed as standard uptake value ratios across composite regions of interest, was observed at Week 104 in the dose groups and placebo group? Numerical estimates and confidence intervals for this endpoint are not reported in the registry record, so the size and precision of any between-group differences cannot be assessed from the record.
The study also set out to assess safety and tolerability. Its brief summary describes the amyloid imaging question as whether ACC-001 with QS-21 could reduce brain amyloid load. That statement describes the study aim, not a finding: the primary outcome is defined as change from baseline, and the registry record does not provide its numerical results. The listed endpoint description says a positive change indicates improvement from baseline. Interpretation should therefore begin with the actual direction and magnitude of each posted estimate, but those values are not reported in the registry record.
3. Trial Design
This was a Phase 2, randomized, placebo-controlled, parallel-group study of ACC-001 with QS-21 in people with early Alzheimer's disease. The registry record lists a total enrollment of 63. The two active regimens were ACC-001 3 μg with QS-21 50 μg and ACC-001 10 μg with QS-21 50 μg; the comparator was placebo identified as phosphate buffered saline. The arm descriptions contain no further details.
The official title calls the study a 24-month trial and identifies it as multicenter. The listed primary outcome timeframe is 104 weeks, with measurement at Week 104. The record gives a start date of 2011-02 and a primary completion date of 2014-02, and the study status is completed.
Randomization is recorded as the allocation method, and the masking field says quadruple. The official title also describes the trial as third-party unblinded. These labels indicate that masking and an unblinded party were part of the design description, but the roles of the masked and unblinded parties are not reported in the registry record. Details such as the randomization procedure and how treatment assignments were concealed are not reported in the registry record.
The primary analysis population is described as the full analysis set, defined as all randomized participants who received at least one dose of investigational product. The record does not give arm-specific analysis counts or explain how participants who did not meet that definition were handled. It lists 35 outcome measures and 205 analyses, but the primary outcome has several categories or time points and is not reduced to one comparison. The statistical plan, including the model used for the primary comparison, is not reported in the registry record. Consequently, the design can be described from the registration details, but a complete account of the analysis cannot be reconstructed from those details.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Participants, who were found eligible, were randomized to 1 of 3 groups in a 1:1:1 ratio between ACC-001 3 μg+QS-21, or ACC-001 10 μg+QS-21, or placebo (which was administrated as phosphate buffered saline \[PBS\]). The study randomization was stratified based on apolipoprotein E (Apo E) genotype (E4 carrier or non-carrier).
Overall Study
| Stage | ACC 3 μg+QS-21 | ACC 10 μg+QS-21 | Placebo |
|---|---|---|---|
| STARTED | 22 | 20 | 21 |
| Treated | 22 | 20 | 21 |
| Completed Treatment | 21 | 18 | 17 |
| COMPLETED | 18 | 18 | 15 |
| NOT COMPLETED | 4 | 2 | 6 |
Reasons for not completing this period:
| Reason | ACC 3 μg+QS-21 | ACC 10 μg+QS-21 | Placebo |
|---|---|---|---|
| No Longer Willing to Participate | 4 | 2 | 5 |
| Participant moved to another town | 0 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: The full analysis set (FAS) population included all randomized participants who had at least one dose of investigational product.
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.
| Characteristic | Unit | ACC 3 μg+QS-21 | ACC 10 μg+QS-21 | Placebo | Total |
|---|---|---|---|---|---|
| Participants analysed | 22 | 20 | 21 | 63 | |
| Age, Continuous | years | 66.8 (SD 7.31) | 68.5 (SD 7.02) | 69.6 (SD 6.82) | 68.3 (SD 7.04) |
| Sex: Female, Male: Female | Participants | 11 | 13 | 9 | 33 |
| Sex: Female, Male: Male | Participants | 11 | 7 | 12 | 30 |
| MMSE Score | score | 27.3 (SD 1.64) | 27.7 (SD 1.63) | 28.0 (SD 1.47) | 27.6 (SD 1.58) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Brain Fibrillar Beta-Amyloid Protein (Aβ) at Week 104 as Measured by Standard Uptake Value Ratios (SUVRs) Over the Composite Regions of Interest (ROIs), measured over 104 weeks.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | ratio |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in brain fibrillar beta-amyloid at Week 104. The measurement is based on retention of florbetapir F18, assessed with positron emission tomography (PET), and expressed as standard uptake value ratios (SUVRs) over composite regions of interest. The registry record states that a positive change indicates improvement from baseline.
As a continuous measure, SUVR represents a quantitative imaging outcome rather than a simple event count. A change score describes how the measurement at follow-up differs from the participant's baseline measurement. Comparing changes between randomized groups can help describe whether the measured amyloid signal followed different patterns across the assigned regimens and placebo. Composite regions of interest combine measurements across designated brain areas; the specific regions and the way the composite was constructed are not reported in the registry record.
Imaging is used in this trial because the stated biological question concerns brain amyloid load, and PET provides the specified means of measuring retention of the imaging agent. The endpoint is a biomarker measure. It should not be treated as a direct measure of every aspect of Alzheimer's disease or of a participant's day-to-day functioning. The registry record does not report numerical estimates, confidence limits, or a numerical comparison for the primary endpoint. It therefore does not allow readers to assess the observed change or its precision from the registration information alone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary endpoint is clearly specified: change from baseline in PET-measured brain fibrillar beta-amyloid at Week 104, reported as SUVR over composite regions of interest. However, the registry record does not report the numerical estimates for the dose groups or placebo, their 95% confidence intervals, or a single primary comparison. Without these values, neither the size nor the direction of the observed between-group differences can be evaluated from the registry record. The stated direction convention—positive change indicates improvement from baseline—does not by itself establish what change occurred.
The endpoint description identifies a least-squares mean and a 95% confidence interval as the summary and dispersion measures. In general, a least-squares mean is a model-based group mean. Its interpretation depends on the model and any included covariates; those details are not reported in the registry record. A confidence interval describes the uncertainty around an estimate under the assumptions of the analysis. It is not a guarantee that the true value lies within its limits, and its width is important when judging precision. Because the numerical intervals are unavailable in the registry record, precision cannot be judged for this endpoint.
The study is randomized and placebo-controlled, which supports a comparison of assigned groups in the trial. But randomization alone does not resolve questions about analysis choices, missing measurements, adherence, or the handling of participants outside the stated full analysis set. Those details are not reported in the registry record. The analysis population includes randomized participants who received at least one dose, so it is not described as all randomized participants regardless of treatment received.
The registry record lists 35 outcome measures and 205 analyses. It also flags that the primary outcome includes several categories or time points and is not reduced to one comparison. As a result, the record does not identify a unique numerical contrast that can be interpreted as the primary result. The analysis plan, selection of contrasts, and treatment of multiple comparisons are not reported in the registry record. A reader should not infer that all reported analyses were prespecified or that multiplicity was controlled.
The safety information is also descriptive. The record gives counts of participants with serious adverse events and other adverse events in each listed group, along with a list of serious-event terms and percentages. These counts provide context about events recorded during the study; without fuller definitions and exposure or follow-up details, they do not establish a causal comparison. Death counts are not reported in the registry record.
Overall, the registry record establishes the trial question, intervention groups, design labels, and endpoint definition, but not the primary numerical outcome. Any conclusion about the magnitude, direction, or precision of the primary endpoint would go beyond the results reported in the record.
9. Statistical Methods Explained
The endpoint is a continuous imaging measure summarized as a least-squares mean, with a 95% confidence interval. These terms describe how the result is expressed, not the full statistical procedure. The statistical model, its covariates, and the exact contrasts used are not reported in the registry record.
What does a least-squares mean represent?
In general, a least-squares mean is an estimate of a group mean from a statistical model. It may account for factors included in that model, unlike a simple arithmetic average calculated directly from the observed values. The adjusted interpretation depends on which factors the model includes and how the model is specified. Since those details are not reported in the registry record, it is not possible to determine what adjustment, if any, underlies the listed least-squares mean. It should not automatically be read as an unadjusted average or as an adjusted comparison between groups.
How should a confidence interval be read?
In general, a 95% confidence interval conveys uncertainty around an estimated quantity under the assumptions of the statistical method. A narrower interval indicates greater precision than a wider interval, considered on the same measurement scale. The interval does not show the range of individual participant values, and it does not remove uncertainty about model choices, missing data, or bias. The endpoint description specifies a 95% confidence interval, but its actual limits are not reported in the registry record. Therefore, readers cannot judge the precision of the primary estimates from the registration details.
What does the change-from-baseline measure capture?
The outcome compares the PET-derived SUVR at follow-up with baseline. This focuses on change over the specified period rather than the follow-up measurement alone. The record identifies florbetapir F18 retention as the imaging basis and composite regions of interest as the measurement area. The way the composite was formed, the handling of baseline values in the model, and the details of image processing are not reported in the registry record. Those choices can matter when interpreting a biomarker change, because measurement definitions determine what the estimate represents.
Why does randomization matter?
In general, random assignment aims to make treatment groups comparable at the start of a study with respect to measured and unmeasured characteristics. A placebo group offers a concurrent reference for interpreting change over time. These design features can strengthen a group comparison, but they do not alone determine how the analysis should be conducted or guarantee that all follow-up data are complete. The registry record identifies randomization, placebo control, and a parallel-group model. The randomization method, allocation concealment, and analysis details are not reported in the registry record.
What can be inferred from the masking description?
The masking field is recorded as quadruple, while the official title describes a third-party unblinded design. In general, masking can reduce the influence of treatment expectations on participant reports, clinical care, outcome assessment, or analysis, depending on who is masked. The record does not identify which roles were masked or explain the third-party unblinding arrangement. It is therefore not possible to specify how masking was implemented or how the unblinded party's role was separated from outcome assessment.
How should the analysis population be understood?
The full analysis set is defined as randomized participants who received at least one dose of investigational product. This definition makes treatment initiation part of inclusion in the primary analysis population. In general, analysis populations can affect which participants contribute to an estimate and what question that estimate answers. The registry record does not report how many participants in each group were included in the primary analysis, what happened to participants without a Week 104 scan, or whether additional populations were analyzed. Missing-data methods are not reported in the registry record.
What do the planning assumptions say?
The registry record describes sample-size calculations as planning illustrations based on the observed effect, not as the trial's own design. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. Such calculations are illustrative planning exercises; they are not observed power and do not establish the trial's original sample-size justification. That justification is not reported in the registry record. The numerical planning illustrations are not included in the registry record details described for this analysis, so no numerical planning requirement can be stated.
The record lists 35 outcome measures and 205 analyses, and notes that the primary outcome has several categories or time points rather than a single reduced comparison. The statistical plan for choosing among analyses, controlling multiplicity, and reporting primary contrasts is not reported in the registry record. The primary endpoint's numerical results are also not reported, leaving no estimate to interpret or recalculate. Any simple unadjusted recalculation would require posted summary statistics that are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 35 outcome measures and 205 analyses. It specifically notes that the primary outcome has several categories or time points and is not reduced to one comparison. This makes it important to know which comparisons were prespecified, how a primary contrast was selected, and whether the analysis accounted for multiple testing. The statistical plan for multiplicity is not reported in the registry record. There is no basis in the record for assuming that multiplicity was or was not controlled.
Missing data are also consequential for an endpoint requiring a Week 104 PET measurement. The primary analysis population is defined as randomized participants who received at least one dose of investigational product, but the record does not say how many participants contributed Week 104 measurements, why any scans might be missing, or how missing values were handled. Imputation methods, sensitivity analyses, and assumptions about missingness are not reported in the registry record. Without those details, readers cannot assess how incomplete follow-up might affect the estimates.
The named full analysis set is narrower than a population defined as all randomized participants, because it requires receipt of at least one dose. The record does not describe other analysis populations or explain whether analyses were conducted according to assigned treatment. The number included in each group for the primary endpoint is not reported in the registry record.
The registry record also does not report the model specification, covariates, analysis hierarchy, or an inferential decision rule for the primary outcome. These omissions do not establish that the trial lacked such methods; they mean that the methods are not reported in the registry record. Numerical primary estimates and confidence intervals are also not reported, so the analysis cannot be independently interpreted or checked against its stated endpoint definition.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| ACC 3 μg+QS-21 | 1 | 22 | 4.5% |
| ACC 10 μg+QS-21 | 6 | 20 | 30.0% |
| Placebo | 6 | 21 | 28.6% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| ACC 3 μg+QS-21 | 20 of 22 |
| ACC 10 μg+QS-21 | 19 of 20 |
| Placebo | 17 of 21 |
Most frequent serious adverse event terms
| Event term | Organ system | ACC 3 μg+QS-21 | ACC 10 μg+QS-21 | Placebo |
|---|---|---|---|---|
| Urinary tract infection | Infections and infestations | 0 of 22 | 1 of 20 | 1 of 21 |
| Basal cell carcinoma | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 1 of 20 | 0 of 21 |
| Lymphoproliferative disorder | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 1 of 20 | 0 of 21 |
| Neurilemmoma benign | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 1 of 20 | 0 of 21 |
| Parathyroid tumour benign | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 0 of 20 | 1 of 21 |
| Pleomorphic adenoma | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 0 of 20 | 1 of 21 |
| Diverticulitis | Infections and infestations | 0 of 22 | 1 of 20 | 0 of 21 |
| Pneumonia | Infections and infestations | 0 of 22 | 1 of 20 | 0 of 21 |
| Asthenia | General disorders | 0 of 22 | 0 of 20 | 1 of 21 |
| Chest discomfort | General disorders | 0 of 22 | 0 of 20 | 1 of 21 |
Most frequent non-serious adverse event terms
| Event term | Organ system | ACC 3 μg+QS-21 | ACC 10 μg+QS-21 | Placebo |
|---|---|---|---|---|
| Injection site reaction | General disorders | 15 of 22 | 16 of 20 | 5 of 21 |
| Upper respiratory tract infection | Infections and infestations | 5 of 22 | 5 of 20 | 3 of 21 |
| Headache | Nervous system disorders | 3 of 22 | 4 of 20 | 3 of 21 |
| Nasopharyngitis | Infections and infestations | 4 of 22 | 3 of 20 | 2 of 21 |
| Dizziness | Nervous system disorders | 3 of 22 | 3 of 20 | 2 of 21 |
| Diarrhoea | Gastrointestinal disorders | 4 of 22 | 3 of 20 | 1 of 21 |
| Anxiety | Psychiatric disorders | 3 of 22 | 2 of 20 | 3 of 21 |
| Nausea | Gastrointestinal disorders | 3 of 22 | 3 of 20 | 1 of 21 |
| Vomiting | Gastrointestinal disorders | 2 of 22 | 2 of 20 | 2 of 21 |
| Fatigue | General disorders | 2 of 22 | 2 of 20 | 1 of 21 |
Serious events with the highest arm-level rate: basal cell carcinoma (5.0%), lymphoproliferative disorder (5.0%), neurilemmoma benign (5.0%), urinary tract infection (5.0%), diverticulitis (5.0%).
The safety record lists serious adverse events for each study group: 1 of 22 participants in the ACC 3 μg+QS-21 group, 6 of 20 in the ACC 10 μg+QS-21 group, and 6 of 21 in the placebo group. It separately lists other adverse events: 20 of 22, 19 of 20, and 17 of 21, respectively. These are the recorded counts and denominators; no additional rates or comparisons are calculated.
The serious adverse event terms listed as top terms are basal cell carcinoma, lymphoproliferative disorder, neurilemmoma benign, urinary tract infection, diverticulitis, and pneumonia, each with a displayed value of 5.0%. The record does not specify a group for each listed term in the registry record for this analysis, so these percentages should not be assigned to a particular treatment group.
In general, adverse-event counts describe events recorded under the trial's reporting definitions; they do not by themselves establish that treatment caused an event. The registry record does not report detailed event definitions, exposure-adjusted rates, timing, duration, or event-level severity beyond the serious-event classification. Death counts are not reported in the registry record. The listed counts should therefore be read descriptively, not as a complete basis for comparing safety between regimens.
12. What the Result Does, and Does Not, Mean
The registry record defines a randomized, placebo-controlled study of two ACC-001 and QS-21 combinations in people with early Alzheimer's disease. Its primary endpoint is change from baseline in a PET-based measure of brain fibrillar beta-amyloid at Week 104. These details identify the question the trial was designed to examine and the way the primary biomarker was measured.
The record does not report the numerical primary endpoint estimates or their 95% confidence intervals. It therefore cannot establish, from the information recorded, how much the measure changed in any group, how the groups compared, or how precisely those estimates were measured. The endpoint description says a positive change indicates improvement from baseline, but that interpretation convention is not itself an observed result.
Even when numerical biomarker changes are available, a PET outcome is a measure of the imaging construct specified in the study. It is not automatically interchangeable with clinical symptoms, everyday function, or other outcomes. The registry record's brief summary also names safety and tolerability as study aims, but the available safety counts are descriptive and do not on their own establish causation or provide a complete assessment.
The design features—randomization, placebo control, parallel groups, and a quadruple-masking designation—are relevant to how a comparison could be conducted. They do not replace the need to examine the analysis population, missing data, endpoint estimates, uncertainty, and prespecified analysis plan. Several of those details are not reported in the registry record. The record also flags multiple categories or time points for the primary outcome without reducing them to a single comparison.
Accordingly, the registry information supports a description of the trial's design and intended measurement, but not a conclusion about the numerical primary result. It does not show from the reported details whether the groups differed, whether any difference was precise, or whether a biomarker finding corresponded to a clinical effect. Those questions require results and analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates why a clearly named endpoint and a numerical result are both needed for statistical interpretation. The registry record specifies a continuous imaging endpoint, the change-from-baseline framework, the Week 104 time point, and the measure used to quantify PET retention. That information clarifies what the trial intended to measure. But without the group estimates and confidence intervals, readers cannot evaluate the magnitude, direction, or precision of the primary result.
It also highlights the role of analysis populations. The stated full analysis set includes randomized participants who received at least one dose. That definition is part of the estimand's context: it helps indicate which participants the primary analysis represents. The number analyzed in each group and the handling of missing Week 104 scans are not reported in the registry record, limiting assessment of how fully the observed data represent the randomized groups.
The record lists many outcome measures and analyses and explicitly identifies multiple categories or time points for the primary outcome. In general, examining multiple outcomes or contrasts can complicate interpretation, because the analysis plan determines which result is primary and how uncertainty is handled across comparisons. That plan is not reported in the registry record. The record therefore cannot establish whether a particular contrast should be treated as definitive.
Finally, the safety counts show why event summaries require context. Counts need their denominators, reporting definitions, and follow-up context to support comparisons, and even then they describe observed events rather than proving causation. The trial's registration details are useful for understanding the study question and measurement strategy, while the absent outcome and analysis details constrain what can be concluded statistically.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpreting this trial from the registry record is that numerical primary endpoint results are not reported. Although the endpoint, summary measure, dispersion measure, and timeframe are identified, estimates and confidence intervals are unavailable. This prevents assessment of the observed changes and their precision, and it prevents a numerical comparison between the active regimens and placebo.
The record notes that the primary outcome involves several categories or time points and is not reduced to one comparison. It does not report which contrast is primary, how comparisons were selected, or how multiplicity was addressed. The analysis model and any covariate adjustment are also not reported in the registry record, limiting interpretation of the stated least-squares means.
Important follow-up details are absent. The record does not give group-specific numbers contributing to the Week 104 analysis, reasons for missing scans, or the method used to handle missing data. Although the primary population is defined as randomized participants who received at least one dose, additional analysis populations and the treatment of participants outside that definition are not described.
The registry record describes quadruple masking and a third-party unblinded design, but does not explain which parties were masked or how the unblinded role operated. It also does not report detailed eligibility criteria, baseline characteristics, arm-specific descriptions, or the specific regions and construction of the composite imaging measure. These omissions limit assessment of comparability, measurement details, and generalizability from the registry information alone.
Safety findings are presented as counts, with a list of serious-event terms and percentages, but detailed definitions, timing, duration, and exposure-adjusted summaries are not reported in the registry record. Death counts are not reported. These limitations mean that the available safety information is descriptive rather than a complete comparative safety analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Amyloid Imaging And Safety Study Of ACC-001 In Subjects With Early Alzheimer's Disease — NCT01227564.
- Registry record last updated 2016-02-25; status last verified 2016-01.
- Results first posted 2016-02-25.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01227564 is a completed Phase 2, randomized, placebo-controlled, parallel-group study of ACC-001 with QS-21 in people with early Alzheimer's disease. The registry record lists enrollment of 63, a start date of 2011-02, and primary completion at 2014-02. It describes two active regimens—ACC-001 3 μg with QS-21 50 μg and ACC-001 10 μg with QS-21 50 μg—and a placebo identified as phosphate buffered saline.
The primary endpoint was change from baseline in brain fibrillar beta-amyloid at Week 104, measured by florbetapir F18 PET as SUVR over composite regions of interest. It is summarized as a least-squares mean with a 95% confidence interval. Numerical primary results, the detailed statistical plan, multiplicity handling, and missing-data methods are not reported in the registry record. Safety counts are recorded for serious and other adverse events, but death counts are not reported in the registry record.