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Alzheimer's Association International Conference (AAIC) · 2024:Poster Tue-17 · Hendrix, Dickson et al.
Companies recently identified clinical study sites engaging in fraudulent practices, reducing success in Alzheimer's disease (AD) clinical trials. Successful trials are reliable…
When the sample size a conventional design demands is larger than the trial you can run, a Global Statistical Test lets the clinical-endpoint hypotheses be tested anyway. The paper sets out when GST applies, how it is pre-specified, and how it has been received in review.
12 publications
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2025 · CNS Drugs
Hendrix, Suzanne · Dickson, Samuel · Durrant, Abe
Amyloid-plaque reduction is currently the only recognized surrogate outcome for Alzheimer’s disease (AD) trials, allowing accelerated approval of plaque-clearing amyloid antibodies. However, plaque reduction does not facilitate the development of new non-plaque-clearing treatments. The hippocampus is among the first brain regions affected by AD pathology, exhibiting synaptic dysfunction and neurodegeneration that manifests as hippocampal atrophy and memory decline. We evaluated hippocampal volume (HV) as a potential surrogate outcome that can predict clinical benefit in disease-modification trials. Using published data from observational and interventional studies that examined both cognition and HV on volumetric magnetic resonance imaging (vMRI), we evaluated the cross-sectional correlations of HV to cognitive performance, the longitudinal correlations of HV atrophy to cognitive decline, HV sensitivity to drug effects, and the correlations between drug effects on HV atrophy and cognitive decline. We also examined the magnitude of HV protection that corresponds to meaningful clinical benefit. Analyses from 30 observational studies encompassing 13,187 individuals (2633 cognitively normal; 10,554 early AD) showed significant cross-sectional correlations between baseline HV and cognition, and longitudinal correlations between HV atrophy and cognitive decline over ≥ 1 year. The relationship of HV–cognitive drug effects was examined at the group level in nine placebo-controlled trials of five antiamyloid agents that evaluated HV in early AD trials of at least 18 months’ duration. These trials included four amyloid antibodies (aducanumab, lecanemab, donanemab, and gantenerumab) and one oral anti-oligomer agent (valiltramiprosate). Individual-level HV–cognition relationships were examined in two valiltramiprosate studies, one of which included diffusion tensor imaging (DTI) providing microstructural correlates of HV drug effects and helping distinguish neuroprotection from brain edema. Across these anti-amyloid drug trials (total N ~10,000), there was a linear relationship between drug effects on slowing of cognitive decline and slowing of HV atrophy. Two anti-oligomer trials (valiltramiprosate) reported significant subject-level correlations between drug effects on HV and cognition over 18–24 months (r = −0.40 to −0.44, p < 0.005, N = 50/69), with significant correlations of drug effects on brain microstructure (decreased mean diffusivity) with both HV and cognitive benefits, supporting reduced neurodegeneration. The minimal HV preservation at the mild cognitive impairment (MCI) stage that is associated with clinical benefit is estimated to be ≥ 40 mm3 or ≥ 10% of atrophy in the placebo arm over 18 months. Our findings demonstrate that hippocampal atrophy is an early indicator of cognitive decline in AD, linked to amyloid and tau-related neurodegeneration. HV on standardized vMRI is sensitive to anti-amyloid treatments, demonstrating strong correlations between slowed hippocampal atrophy and slowed cognitive decline. Data from over 23,000 subjects over three decades support HV as a surrogate marker for predicting clinical benefit in early symptomatic AD.
2025 · Alzheimer's & Dementia
Duncan, Garrett · Dickson, Samuel · Johnson, Sam · Dayley, Caleb · Hendrix, Suzanne · Mallinckrodt, Craig
INTRODUCTION: The importance of biomarkers as a primary outcome or as supportive evidence of clinical effect is rising as the field shifts toward disease-modifying treatments and earlier intervention, because they have lower variability and can indicate disease progression earlier than clinical outcomes. This study assessed the performance of plasma pTau 181 and 217 as a predictive biomarker and potential primary endpoint in early-phase Alzheimer’s disease (AD) trials. METHODS: Summary data from recent monoclonal antibody (mAb) trials including plasma pTau 181 and 217 were analyzed to evaluate associations between plasma pTau 181/217 and clinical outcomes. The suitability of plasma pTau 181/217 as a surrogate endpoint for internal decision making was assessed using Prentice criteria. Simulations were conducted to explore the statistical power of using plasma pTau 181/217 as a primary outcome in dose-escalation, proof-of-concept (POC) trial designs. Additional criteria for biomarker validation were applied to simulated data. RESULTS: A strong group-level correlation (r = 0.781) was observed between treatment effects on plasma pTau 181/217 and Clinical Dementia Rating scale – Sum of Boxes (CDR-SB). Mean change in plasma pTau 181/217 significantly predicted mean change in CDR-SB (p = 0.013). The treatment effect on pTau 181/217 was ∼2.6 times greater than on CDR-SB. Prentice Criteria 1, 2, and 4 were met or reasonably met; Criterion 3 is not applicable in the POC setting. CONCLUSION: Plasma pTau 181/217 at 6 months shows future promise to reasonably likely predict clinical benefit for drugs that reduce pTau 181/217 levels, supporting its use as a primary endpoint in early-phase trials. With effect sizes similar to those seen with donanemab, adequately powered trials may require as few as 100 participants. Such trials should include prespecified analyses to evaluate individual-level Prentice criteria, and pTau 181/217 results can be used to predict potential Phase 3 clinical outcomes.
2025 · Parkinsonism and Related Disorders
Dickson, Samuel · O'Keefe, Patrick · Hendrix, Suzanne
Background: The measures used to assess Parkinson’s disease (PD) in clinical trials were developed for a broad spectrum of disease severity, limiting their ability to detect meaningful changes in early PD over a feasible study period. Objective: To develop PD composite scales (PARCOMS) using clinical trials data with increased responsiveness to clinical decline in patients with early untreated disease. Methods: Subjects from the placebo arms of clinical trials (Critical Path for Parkinson’s [CPP] dataset), diagnosed with PD within the previous two years, with no current or prior use of dopaminergic therapies were included. Partial least squares (PLS) regression was used to develop two composite scales: PARCOMS-Function using items from the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part II and Parkinson’s Disease Questionnaire (PDQ-39) scales, and PARCOMS-Motor using items from MDS-UPDRS Parts II and III. Scale responsiveness was estimated using mean to standard deviation ratios (MSDRs) for change from baseline at 12-months. Results: The MSDR for PARCOMS-Function (n = 140) was 12.3 % higher vs MDS-UPDRS Part II alone and 339 % higher vs PDQ-39 alone. The MSDR for PARCOMS-Motor (n = 181) was 27.5 % higher vs the combined MDS- UPDRS Parts II and III. PARCOMS-Function retained 15-items (34.1 %) from Part II and PDQ-39. PARCOMS-motor retained 23-items (50.0 %) from Part II and III. Items that were not responsive to change or that were correlated with more responsive items were omitted. Conclusions: Clinical trial data were used to develop two PARCOMS scales which demonstrated greater sensitivity to disease progression in patients with early PD over 12-months compared to the original scales.
2025 · Journal of Alzheimer’s Disease
Haaland, Benjamin · Dickson, Samuel · Christensen, Joshua · Mallinckrodt, Craig · Hendrix, Suzanne
Background The AFF006 trial (NCT01117818) provided unexpected evidence of benefits of the vaccine adjuvant AD04 (aluminum oxyhydroxide) in patients with early Alzheimer's disease (AD), compared with AD02, a vaccine consisting of a peptide that mimics the N-terminal region of human amyloid-β (Aβ) conjugated with keyhole limpet hemocyanin. Objective The objective of this post hoc analysis was to assess whether this unexpected benefit of AD04 was an artifact of multiple testing (i.e., type I error inflation) or a robust result. Methods In this post hoc assessment, we used permutation testing to estimate type I error inflation due to the evaluation of multiple outcomes in AFF006. Efficacy was assessed using a patient-level global statistical test combining composite endpoints of cognition, function, and global AD. In addition, we examined the observed treatment benefits of AD04 in the context of effects observed in trials of aducanumab, donanemab, and lecanemab, monoclonal anti-Aβ antibodies that received regulatory approval for AD. Results The global statistical test suggested a treatment benefit of AD04 versus ineffective AD02 arms, even after accounting for multiplicity (primary methodology p-value, 0.03; permutation test p-value, 0.02). The observed effect estimates for AD04 compared favorably with approved monoclonal antibodies. Conclusions Post-hoc analyses are hypothesis generating rather than confirmatory. Adjusting for multiplicity using permutation testing can determine whether post-hoc effects are worth pursuing, or unlikely to be confirmed. These analyses have motivated a follow-up prospective randomized controlled trial, ADVANCE (EudraCT 2022-003532-73), in which optimized AD04 dosing will be compared to placebo in early AD.
2025 · Neurotherapeutics
Despite current medical therapy for Parkinson's Disease (PD), many experience persistent motor symptoms and significant unmanaged non-motor issues. Previous studies suggest that light therapy (LT) provides benefits for motor and non-motor features of PD. This study evaluated Circadian Effective LT (CELT) with a spectral band between 460 and 545 nm for the motor and non-motor features of PD. We conducted a multi-center, randomized, double-blind, controlled clinical trial of CELT in people with Parkinson's disease on standard-of-care therapy. Ninety-two participants (45 active, 47 control) were randomized 1:1 to active or control CELT for 1 h each evening for 6 months. Patients were evaluated in their ‘ON state’. The mean (SE) change on the primary endpoint of the MDS-UPDRS parts 1–3 was −17.7(2.8) active vs −9.7(3.5) control, for a LSM difference of −8.0 (4.4) (p = 0.074, 95% Confidence Interval: −16.7, 0.8), reflecting a trend toward improvement over control. Key secondary endpoints included PDQ-39 and CGI which favored active treatment (−5.7 ± 2.7; p = 0.038, and −0.4 ± 0.2; p = 0.066 respectively), while PDSS-2 Disturbed Sleep showed no difference between groups. Other secondary endpoints that supported the overall treatment effect of CELT included ESS (−1.52 ± 0.78; p = 0.054) and CGI-E (−0.3 ± 0.2; p = 0.088). Daily LT, with a circadian effective targeted spectrum of light, was well tolerated by PD patients, had no serious adverse effects and showed improvement in both motor and non-motor MDS-UPDRS and other scores. Larger double-blind studies are warranted to further assess the effectiveness of CELT in PD.
2025 · Neurol Ther
Dickson, Samuel · O'Keefe, Patrick · Hendrix, Suzanne
Introduction: Measures designed to comprehensively assess Parkinson's disease (PD) irrespective of disease stage and treatment status may be unable to capture nuances in disease progression, particularly in early-stage PD. The objective of this paper is to develop PARkinson's COMposite Scales (PARCOMS) with increased responsiveness to clinical decline using items of the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) for three discrete cohorts of patients. Methods: Patients with confirmed PD from the Parkinson's Progression Markers Initiative (PPMI) data were assigned to three cohorts based on use of dopaminergic treatment, stage of disease, and presence of motor complication. For each cohort, items from MDS-UPDRS Part I (PARCOMS-Non-Motor) and Parts II and III (PARCOMS-Motor) were selected based on responsiveness using partial least squares (PLS) regression. The responsiveness of the scales was estimated using mean-to-standard deviation ratios (MSDRs) of their change values. Results: Compared to the original MDS-UPDRS, MSDRs for PARCOMS-Motor increased 13.1% (untreated cohort, n = 430), 78.2% (treated-without-motor-complications cohort, n = 426), and 100.6% (treated-with-motor-complications cohort, n = 538). The MSDR increases observed for PARCOMS-Non-Motor were 13.9%, 6.8%, and 20.7%, respectively. Across cohorts, turning in bed and speech items were large contributors to the PARCOMS-Motor scales. Items for cognitive impairment and urinary problems were substantial contributors to PARCOMS-Non-Motor across cohorts. There was variability in the weighting of items representing different clinical concepts across cohorts for each composite, confirming heterogeneity in disease progression across disease stages. Conclusions: PD stage-specific composite measures were developed and demonstrated greater sensitivity to change than the original MDS-UPDRS, supporting the value of weighted composites tailored for disease stage.
2025 · Alzheimers Dement (N Y)
Haaland, Benjamin · Nicodemus-Johnson, Jessie · Dickson, Samuel · Christensen, Joshua · Mallinckrodt, Craig · Hendrix, Suzanne
Introduction: Gamma oscillations in the brain are necessary for normal cognitive function, sensory processing, and memory consolidation, and are reduced in Alzheimer's disease (AD). In a 6 month, randomized, feasibility trial in participants with mild-to-moderate AD (OVERTURE [NCT03556280], n = 76), a non-invasive method for sensory-evoked brain gamma oscillations outperformed sham on the secondary outcomes of slowing decline on the Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) functional scale, magnetic resonance imaging measures of whole brain volume and the Mini-Mental State Examination (MMSE) cognitive outcome, despite not showing statistical significance on the primary outcome (Mild and Moderate Alzheimer's Disease Composite [MADCOMS]), a composite cognitive-functional score. In this post hoc analysis of OVERTURE, we evaluated the effects of investigational sensory-evoked gamma oscillation treatment in terms of time saved, as an estimate of slowing in disease progression, on ADCS-ADL, MMSE, and whole-brain volume. Methods: Disease trajectories based on the ADCS-ADL, MMSE, and whole-brain volume changes from baseline within each treatment group were constructed using mixed-effects models. Horizontal projection from active to sham arm yielded time saved from baseline at each visit. Data from the open label extension (OLE) phase of the OVERTURE study have also been used to analyze the time-saving effect of active treatment in an extended period. Results: Compared to sham, time savings of 4.83, 4.59, and 4.09 months over 6 months of active treatment on ADCS-ADL, MMSE, and whole-brain atrophy were observed in the randomized controlled trial phase. When including the OLE phase, time savings of 8.66, 10.00, and 7.48 months over 14.64, 15.98, and 13.46 months of active treatment on ADCS-ADL, MMSE, and whole-brain atrophy were observed relative to the sham group. Discussion: These findings suggest that further exploration of the effect of evoked gamma oscillations in participants with mild-to-moderate AD, as well as the evaluation of treatment effects using time saved, is merited. Highlights: Evoked gamma oscillation slows functional loss and brain atrophy in Alzheimer's disease.Slowing of functional and cognitive decline and brain atrophy worsening can be expressed as time saved.Evoked gamma oscillation saves 4.83 months of progression in activities of daily living, 4.59 months of progression in Mini-Mental State Examination, and 4.09 months of decline in whole-brain volume over 6 months.
2025 · Neurotherapeutics
Johnson, Sam · Hendrix, Suzanne
Senescent cell accumulation contributes to the progression of age-related disorders including Alzheimer's disease (AD). Clinical trials focused on cellular senescence are in early stages and have yet to establish reliable outcome measures reflecting senescent cell burden or response to senolytics, therapeutics that clear senescent cells. Results from the first open-label trial of senolytics, dasatinib plus quercetin (D + Q), in older adults (N = 5) with early AD demonstrated central nervous system penetration of dasatinib and favorable safety and tolerability. Herein, we present exploratory analyses of senescence and AD-associated analytes in blood, cerebrospinal fluid (CSF) and urine from this study in effort to guide biomarker development for future senolytic trials. Immunoassays, mass spectrometry and transcriptomics were performed and changes in analyte levels were assessed from baseline to post-treatment using paired t-tests. Targeted cytokine and chemokine analyses revealed increases in plasma fractalkine and MMP-7 and CSF IL-6 from baseline to post-treatment. Mass spectrometry indicated stable levels of amyloid β and tau proteins in CSF, unchanged urinary metabolites, and modest treatment-associated lipid profile changes. Targeted transcriptomic analysis of peripheral blood mononuclear cells indicated downregulation of inflammatory genes including FOS, FOSB, IL1β, IL8, JUN, JUNB, PTGS2. The levels and treatment responses of the analytes identified here may help inform trial design and outcomes for senolytic studies. Independent validation will be necessary to develop standardized biomarker panels across senolytic trials for AD. ClinicalTrials.gov: NCT04063124.
2025 · NEJM Evid
Background: We tested the ability of a single intravitreal injection of foselutoclax (hereafter UBX1325), a novel senolytic small molecule inhibitor of antiapoptotic protein B-cell lymphoma-extra large, to mitigate the impact of diabetic macular edema. Methods: Patients with diabetic macular edema with prior suboptimal response to anti-vascular endothelial growth factor treatment were randomly assigned (1:1) to either a single intravitreal injection of 10 μg of UBX1325 or sham and were followed for up to 48 weeks. The primary trial objective was to evaluate the safety and side-effect profile of UBX1325 as assessed by ocular and systemic treatment-emergent adverse events (TEAEs). Our secondary objective was to probe efficacy, defined as mean changes from baseline for UBX1325 versus sham in best corrected visual acuity measured in Early Treatment of Diabetic Retinopathy Study (ETDRS) letters (range, 0-100 letters, higher scores indicate better vision) and retinal structure. Results: Between June 2021 and April 2022, 65 participants (32.3% women) were randomly assigned to either UBX1325 (n=32) or sham (n=33). There were four TEAEs of Grade 3 or greater in the sham group, of which three were considered serious, while there were five in the UBX1325 group of Grade 3 or greater and considered serious. There were no apparent between-group differences with respect to vital signs, electrocardiograms, or routine blood chemistries. For the secondary outcome of efficacy, the difference between UBX1325 and sham in mean change to week 48 in best corrected visual acuity was 5.6 more ETDRS letters (95% confidence interval, -1.5 to 12.7). Conclusions: In this sham-controlled trial there were no TEAEs that led to discontinuation of treatment with UBX1325 compared with sham. There were trends suggestive of potential efficacy; larger trials are needed to further evaluate these findings. (Funded by UNITY Biotechnology; ClinicalTrials.gov number, NCT04857996.).
2025 · J Prev Alzheimers Dis
Donanemab (Kisunla®), an IgG1 monoclonal antibody targeting N-terminal pyroglutamate-modified forms of amyloid-β, is approved in the United States for treatment of early symptomatic Alzheimer's disease (AD). Appropriate Use Recommendations (AUR) were developed to guide the implementation of donanemab in real-world practice, prioritizing safety considerations and opportunity for effectiveness. The AUR were developed by the AD and Related Disorders Therapeutic Workgroup by consensus, integrating available data and expert opinion. Appropriate candidates for donanemab treatment include persons with mild cognitive impairment or mild dementia due to AD (Clinical Stages 3-4, MMSE 20-30) who have biomarker confirmation of AD pathology by PET or CSF. Tau PET is not required for eligibility. Apolipoprotein E (APOE) genotyping should be performed prior to treatment to inform an individual's risk of developing Amyloid-Related Imaging Abnormalities (ARIA). Pre-treatment MRI should be obtained no more than 12 months prior to treatment. Patients with findings of >4 cerebral microbleeds, cortical superficial siderosis or a major vascular contribution to cognitive impairment should be excluded from treatment. The decision to initiate therapy should be grounded in a shared decision-making process that emphasizes the patient's values and goals of care. Donanemab is administered as a monthly intravenous infusion. Surveillance MRIs to evaluate for ARIA should be performed prior to the 2nd, 3rd, 4th and 7th infusions, prior to the 12th dose in higher risk individuals, and at any time ARIA is suspected clinically. Clinicians may consider discontinuing treatment if amyloid clearance is demonstrated by amyloid PET, typically obtained 12-18 months after initiating treatment.
2025 · Int Psychogeriatr
Background: Alzheimer's disease (AD) is often associated with agitation and aggression, which may impair function, impede care, and be a major source of stress for caregivers. The Cohen-Mansfield Agitation Inventory (CMAI) is often used to assess agitation and aggression. In its original, nursing-home version, it is a 29-item, caregiver-informed, clinician-administered 7-point scale that assesses the frequency of various agitation or aggressive behaviors. However, the instruction manual advises against the use of the total score in favor of a domain-based analysis. This recommendation has been followed in both clinical trials and practice. Because the CMAI is comprehensive and easy to administer, we sought to determine the validity of its total score as a single construct for assessing agitation and aggression in patients with AD. Methods: We used a previously conducted factor analysis of the CMAI scores from two risperidone trials in patients with dementia (N = 648), and a follow-up analysis of the subset of patients with psychosis of AD (N = 479), to examine, using vector analysis and an effect-size-versus-signal-to-noise ratio analysis, whether the total CMAI score could confidently be used as a global measure of agitation and aggression in AD. Results: Our findings suggest that the CMAI items from the dataset analyzed load into 4 clusters, which cover about 50 % of the total data variance. Surprisingly, items with the lowest signal-to-noise ratio (hitting, performing repetitious mannerisms, aimless pacing or wandering) had the strongest response to treatment (and vice versa), and belonged to different factors. The further observation that many items were spread among the factors, instead of primarily measuring a single factor or domain, suggests that there is a continuum of symptoms, and separating them into domains requires separating very similar items that measure two or more domains. Conclusions: These findings suggest that assessing agitation and aggression via CMAI domains instead of the total score is likely to miss important behavioral signals. Using total CMAI score in clinical trials and practice, along with the assessment of individual items, is warranted.
2025 · J Prev Alzheimers Dis
There is growing consensus in the Alzheimer's community that combination therapy will be needed to maximize therapeutic benefits through the course of the disease. However, combination therapy raises complex questions and decisions for study sponsors, from preclinical research through clinical trial design to regulatory, statistical, and operational considerations. In January 2024, the Alzheimer's Drug Discovery Foundation convened an expert advisory board to discuss the key considerations in each of these areas. Experts agreed on the need to prioritize a combination therapy approach that encompasses a wide range of targets associated with aging and the underlying biology of Alzheimer's disease. Progress in combination therapy could be accelerated by leveraging preclinical research and Phase 1 and 2A trials to identify the most promising combinations for further development, exploring repurposed agents with available preclinical and clinical data, building collaborations across sectors to support operational challenges, and planning for the likely impact of anti-amyloid beta-protein monoclonal antibody therapies on future clinical trial designs.
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