Amyloid-β

Pericyte loss in cognitive-impairment-prone hippocampal regions precedes blood-brain barrier breakdown and is detectable before clinical Alzheimer disease symptom onset; this provides a timing-window for biomarker-driven intervention.

Gantenerumab subcutaneous dosing reduces brain amyloid in prodromal AD in a dose-dependent manner; a Phase II extension study demonstrated near-complete amyloid clearance at higher doses, informing the dose selection for the Phase III trials.

Verubecestat (BACE1 inhibitor) Phase III EPOCH trial in mild-moderate AD halted for futility; cognitive worsening signal observed. Production-side amyloid intervention failed alongside MAb clearance approaches, narrowing therapeutic-window viability of the amyloid hypothesis.

ATV:TREM2 agonist antibody brain shuttle construct (ATV fused to anti-TREM2 agonist) achieves 50-fold higher brain exposure than unmodified antibody and shows superior microglial activation and plaque reduction in 5xFAD mice compared with anti-TREM2 alone, providing in vivo validation of the ATV platform for TREM2...

Covers mAb158, the murine precursor to lecanemab (BAN2401), a protofibril-selective anti-Aβ IgG1 antibody with 200–1000-fold selectivity for protofibrils over monomers; basis for Leqembi FDA approval.

Population-based longitudinal study shows amyloid accumulation begins ~15–20 years before estimated AD onset; accumulation rate decelerates near symptom onset once a plateau is reached, suggesting a narrow therapeutic window for anti-amyloid interventions.

Covers Genentech's low-affinity anti-TfR antibodies that facilitate BBB transcytosis without inhibiting transferrin or HFE binding; foundational patent on affinity-tuning TfR antibodies to escape lysosomal trapping and achieve CNS delivery.

Granted US patent on specific sequence-defined bispecific antibodies that bivalently bind Aβ plaques and monovalently bind TfR1; covers the structural format used in trontinemab for enhanced CNS delivery.

Solanezumab (anti-Aβ monoclonal) failed primary cognitive endpoints in EXPEDITION1 and EXPEDITION2 Phase III trials in mild-moderate Alzheimer's. Class-leading early test of the anti-Aβ MAb hypothesis in symptomatic AD; outcome reduces confidence in amyloid-cascade-as-drug-target in mild-moderate AD.

Anti-Amyloid Monoclonal Antibodies for the Treatment of Alzheimer's Disease. — Two monoclonal antibodies (mAbs), aducanumab and lecanemab, have received accelerated approval from the US FDA for initiation of treatment in early Alzheimer's disease patients who have proven β-amyloid pathology (Aβ). One of these,...

In DIAN-TU, gantenerumab and solanezumab did not significantly slow cognitive decline in autosomal-dominant AD mutation carriers despite reducing biomarker targets; negative results suggest treatment initiation may need to begin earlier in the disease cascade.

Re-engineering of the anti-transferrin receptor antibody 8D3 to monovalent binding increases BBB transcytosis efficiency 10-fold over bivalent format; monovalent TfR engagement avoids receptor downregulation and enables superior brain uptake of antibody-drug conjugates.

Core platform patent for Roche Brain Shuttle (BrainShuttle): monovalent single-chain Fab against TfR1 fused to therapeutic IgG; monovalent format prevents lysosomal sorting, enabling 55-fold increase in brain Aβ engagement versus parent antibody.

BAN2401 (lecanemab precursor, anti-protofibril Aβ antibody) in a Phase IIb dose-finding study showed dose-dependent amyloid lowering; Bayesian adaptive design provided early evidence of clinical slowing on ADCOMS in the highest-dose arm.

Subcutaneous lecanemab maintenance dosing in CLARITY-AD open-label extension maintains amyloid clearance achieved during IV dosing phase; participants who cleared amyloid remain Aβ-negative at 18-month follow-up, suggesting potential for extended dosing intervals once clearance is achieved.

Foundational composition patent for gantenerumab, a fully human IgG1 anti-Aβ antibody generated via MorphoSys HuCAL technology; binds dual N-terminal (AEFRHDSGY) and central (VHHQKLVFFAEDVG) Aβ epitopes on aggregated fibrillar forms.

Donanemab in TRAILBLAZER-ALZ 4 demonstrates that early tau burden (low/medium tau PET) selects for greater clinical benefit; donanemab-treated participants with low/medium tau showed 35% slower iADRS decline vs. placebo at 18 months, underscoring importance of biomarker-based patient selection.

Donanemab (anti-pyroglutamate-Aβ MAb) shows positive primary endpoint in early symptomatic AD with low/medium tau PET burden. Tau PET stratification meaningfully modifies treatment effect — high-tau subgroup shows attenuated benefit. ARIA-E rate ~24%; APOE4-dose-dependent.

Lecanemab (anti-Aβ protofibril antibody) in the AHEAD 3-45 substudy demonstrates that cognitively unimpaired adults with intermediate amyloid burden achieve greater amyloid lowering than those with elevated amyloid, suggesting preclinical treatment may require prolonged dosing to achieve clearance.

Donanemab (anti-N3pG Aβ antibody) in Phase II TRAILBLAZER-ALZ reduced amyloid plaque load to near-zero in a majority of participants and slowed clinical decline on the iADRS by 32% versus placebo at 76 weeks in early symptomatic AD.

Anti-amyloid immunotherapy ARIA (amyloid-related imaging abnormalities) — edema (ARIA-E) and microhemorrhage (ARIA-H) — occurs in 15-40% of APOE4 carriers receiving high-dose anti-Aβ antibodies; radiological characterization and risk stratification framework published to guide clinical management.

APOE4 carrier status increases the importance of ARIA risk stratification for anti-amyloid antibody treatment.

Lecanemab slowed decline on CDR-SB in early Alzheimer's disease in CLARITY AD, with a modest absolute effect that requires patient-level risk stratification.

Donanemab slowed clinical decline in early symptomatic Alzheimer's disease in TRAILBLAZER-ALZ 2, with efficacy interpreted against amyloid and tau-selection criteria.

Donanemab treatment increases ARIA risk, making benefit interpretation inseparable from imaging surveillance and patient selection.

Amyloid-Related Imaging Abnormalities With Donanemab in Early Symptomatic Alzheimer Disease: Secondary Analysis of the TRAILBLAZER-ALZ and ALZ 2 Randomized Clinical Trials. — ImportanceAmyloid-related imaging abnormalities (ARIA) are the major adverse event associated with amyloid-targeting immunotherapy....

Reducing anti-TfR antibody affinity for transferrin receptor enhances receptor-mediated transcytosis and brain uptake; bispecific anti-TfR/BACE1 antibody lowers brain Aβ in mice after single systemic dose. Mechanistic foundation of the Brain Shuttle delivery class.

Anti-TfR/BACE1 bispecific antibodies cross BBB in cynomolgus monkeys; reduce CSF and brain-tissue Aβ in dose-dependent fashion correlated with brain antibody concentration. Translates Yu 2011 mouse PK/PD into NHP, supporting clinical Brain Shuttle development.

Gantenerumab GRADUATE I and II failed to meet primary clinical endpoints despite amyloid-lowering rationale, reinforcing that target engagement alone does not guarantee clinical translation.

Verubecestat failed to improve cognition or function in mild-to-moderate Alzheimer's disease despite BACE1 target engagement.

Covers Roche Elecsys electrochemiluminescence immunoassay (ECLIA) for quantifying Aβ1-42 and Aβ1-40 in CSF using sandwich principle with biotinylated 21F12 and ruthenium-labeled 3D6 antibodies; FDA 510(k)-cleared 2022.

P-glycoprotein expression at the blood-brain barrier declines with age and is further reduced in Alzheimer's disease, contributing to amyloid-beta accumulation by impaired cerebral efflux; this is the same transporter that excludes most oncology drugs from glioblastoma at the infiltrative margin.

Merck patent on iminothiadiazine dioxide scaffold BACE inhibitors encompassing the verubecestat (MK-8931) compound class; covers C2-ring-substituted variants of the thiadiazinane core used in the EPOCH and APECS Phase 3 trials.

TRAILBLAZER-ALZ 3 (NCT05026866): Tau PET and amyloid PET dual-enrichment; donanemab dosing until amyloid clearance confirmed.

AHEAD A3 (NCT04468659) is a Phase III preclinical-AD lecanemab trial in cognitively-unimpaired adults with intermediate amyloid; eligibility uses APOE genotype stratification, with the 2022 SAP amendment refining APOE4-positive arm allocation in line with APOE4-specific BBB/pericyte evidence.

TRAILBLAZER-ALZ Phase II (NCT03367403): Significant slowing of iADRS decline (−6.86 vs −10.06); rapid and near-complete amyloid clearance confirmed.

TRAILBLAZER-ALZ 6 (NCT05738486): Monthly SC dosing design; co-primary ARIA safety and amyloid clearance endpoints.

Solanezumab did not slow cognitive decline in the A4 preclinical Alzheimer's disease trial, weakening soluble amyloid-beta targeting as prevention monotherapy.

Lecanemab reduced amyloid burden and shifted downstream biomarkers in CLARITY AD, but biomarker movement remained larger than the observed clinical effect.

Anticoagulant use and hemorrhage risk modify the eligible population for anti-amyloid antibody treatment.

Critical assessment of anti-amyloid-β monoclonal antibodies effects in Alzheimer's disease: a systematic review and meta-analysis highlighting target engagement and clinical meaningfulness. — Despite most monoclonal antibodies against Aβ in Alzheimer's failed to demonstrate efficacy, the newest antibodies showed...

Amyloid-Related Imaging Abnormalities (ARIA) in Clinical Trials of Gantenerumab in Early Alzheimer Disease. — ImportanceData from 2 phase 3 studies of gantenerumab, GRADUATE I/II, and their open-label extensions represent a resource to further characterize amyloid-related imaging abnormalities (ARIA), including...

Amyloid-related imaging abnormalities (ARIA): diagnosis, management, and care in the setting of amyloid-modifying therapy. — Amyloid-related imaging abnormalities, were originally described by dementia care experts. The wider use of aducanumab and now lecanemab warrant broader understanding by the health care...

Lecanemab Treatment in a Specialty Memory Clinic. — ImportanceTwo monoclonal antibodies targeting amyloid plaques, lecanemab and donanemab, have received traditional US Food and Drug Administration (FDA) approval for the treatment of early symptomatic Alzheimer disease (AD). The most significant adverse events...

Disease-modifying therapies for Alzheimer's disease: Clinical trial progress and opportunity. — The U.S. Food and Drug Administration (FDA) recently approved lecanemab and donanemab for the treatment of early symptomatic Alzheimer's disease (AD) after their phase III trials reached endpoints. These two anti-amyloid...

Systematic in silico analysis of clinically tested drugs for reducing amyloid-beta plaque accumulation in Alzheimer's disease.

Lecanemab preferentially binds to smaller aggregates present at early Alzheimer's disease.

Maximizing the benefit and managing the risk of anti-amyloid monoclonal antibody therapy for Alzheimer's disease: Strategies and research directions. — Anti-amyloid monoclonal antibodies (MABs) have introduced a new era of Alzheimer's disease (AD) therapeutics with disease-targeted drugs. Three agents ---...

Immunotherapies Targeting Amyloid and Tau Protein in Alzheimer's Disease: Should We Move Away from Diseases and Focus on Biological Targets? A Systematic Review and Expert Opinion.

Anti-amyloid programs can produce large amyloid biomarker changes while producing modest, absent, or discordant cognitive effects.

Aducanumab approval did not establish a stable clinical translation pathway for anti-amyloid therapy because the program was discontinued after contested evidence and restricted uptake.

A4 Study (NCT02008357) preclinical solanezumab arm halted 2020 after EXPEDITION3 + multi-cohort futility analysis; preclinical AD as solanezumab indication ruled out alongside mild-AD.

DIAN-TU solanezumab arm (dominantly inherited AD prevention) terminated for futility 2020; soluble-Aβ-targeting MAb framework not viable in preclinical AD even in fully penetrant genetic risk.

Reimbursement decisions: CMS National Coverage Determination (April 2022) restricted aducanumab Medicare coverage to clinical trial enrollment only — a near-zero coverage outcome in practice — citing insufficient evidence of clinical benefit despite FDA approval. Biogen withdrew aducanumab from market Jan 2024.

Roche-Denali Brain Shuttle gantenerumab (Trontinemab / RG6102, NCT04374253) program scope reflects BBB-transcytosis-as-delivery-target architecture; following Montagne 2020 APOE4-stratified BBB evidence, program decision-making prioritizes APOE4-stratified PK/PD readouts and BBB-permeability biomarker integration.

AHEAD A3 (NCT04468659) lecanemab preclinical-AD trial protocol mandates APOE genotyping and stratified arm allocation; eligibility design directly references prior anti-Aβ MAb ARIA-E APOE4-dose-dependence including bapineuzumab 302.

Field consensus 2018-2022 shifted from soluble-Aβ targeting (solanezumab class) to aggregated-Aβ + protofibril targeting (lecanemab, donanemab, aducanumab); EXPEDITION3 read as definitive evidence that soluble Aβ is downstream marker not therapeutic substrate.

Amyloid PET <i>Z</i> Score Quantification and Correlation with Visual Semiquantitative Grading.

Brain Amyloid Plaque Levels Affect Clinical Progression in Alzheimer Disease: Assessment of Amyloid PET and Change in CDR-SB Utilizing Semi-Mechanistic Model. — Lecanemab is a humanized IgG1 monoclonal antibody binding with high affinity to protofibrils of amyloid-beta (Aβ) protein. In clinical studies, lecanemab...

Evaluation of 18F-flutemetamol amyloid PET image analysis parameters on the effect of verubecestat on brain amlyoid load in Alzheimer's disease. — PurposeThe BACE inhibitor verubecestat was previously found to reduce amyloid load as assessed by 18F-flutemetamol positron emission tomography (PET) composite cortical...

Posttreatment Amyloid Levels and Clinical Outcomes Following Donanemab for Early Symptomatic Alzheimer Disease: A Secondary Analysis of the TRAILBLAZER-ALZ 2 Randomized Clinical Trial. — ImportanceAccumulation of amyloid plaque drives pathogenesis of Alzheimer disease (AD). Reduction of amyloid via...

Monoclonal antibodies against beta-amyloid protein (lecanemab and donanemab) should not be used in the treatment of Alzheimer's disease. — Two antiamyloid monoclonal antibodies (mAbs), lecanemab and donanemab, were recently launched for treatment of Alzheimer's disease (AD). These mAbs remove amyloid protein from...

Balancing Speed and Sensitivity: Echo-Planar Accelerated MRI for ARIA-H Screening in Anti-Aβ Therapeutics. — The recent advent of anti-amyloid-β monoclonal antibodies has introduced new demands for MRI-based screening of amyloid-related imaging abnormalities, particularly the hemorrhage subtype (ARIA-H). In this...

How will the emergence of lecanemab change dementia treatment? — The introduction of lecanemab has dramatically changed the field of dementia medicine. Lecanemab, defined as an anti-amyloid-β (Aβ) drug, comprises an antibody against Aβ, a protein structure believed to cause Alzheimer's disease. This drug represents...

Incidence of Amyloid-Related Imaging Abnormalities in Phase III Clinical Trials of Anti-Amyloid-β Immunotherapy: An Updated Meta-Analysis.

Concordance between Centiloid Quantification and Visual Interpretation of Amyloid PET Scans across the Alzheimer Disease Continuum.

The effect of modified donanemab titration on amyloid-related imaging abnormalities with edema/effusions and amyloid reduction: 18-month results from TRAILBLAZER-ALZ 6. — The TRAILBLAZER-ALZ 6 study (NCT05738486) evaluated the effect of different donanemab dosing regimens on amyloid-related imaging abnormalities...

Influence of patient characteristics on efficacy and safety of anti-amyloid monoclonal antibodies in Alzheimer's disease: A systematic review and meta-analysis.

Safety of switching from lecanemab to donanemab in 20 consecutive patients with Alzheimer's disease. — We retrospectively reviewed 20 consecutive patients with Alzheimer's disease who switched from lecanemab to donanemab. No new amyloid-related imaging abnormalities (ARIA) or significant adverse events were...

CHIT1 and DDAH1 levels relate to amyloid-related imaging abnormalities risk profile in Alzheimer's disease patients.

Lecanemab appropriate use recommendations for clinical practice in the UK. — Lecanemab is an anti-amyloid monoclonal antibody, recently approved in the UK as a treatment for mild cognitive impairment (MCI) and mild dementia due to Alzheimer's disease (AD) in adults who are apolipoprotein E ε4 gene (APOE4)...

Anti-amyloid immunotherapies for Alzheimer's disease: Administration, side effects, and overall framework. — Recently, the Food and Drug Administration (FDA) approved the use of aducanumab (Aduhelm), lecanemab (Leqembi), and donanemab (Kisunla) in patients with mild cognitive impairment (MCI) and early-stage...

Anti-amyloid β Antibody Therapies for Alzheimer's Disease: Association between the Target of Amyloid β Aggregates and the Clinical Efficacy of Anti-amyloid β Antibody. — Phase 3 clinical trials have validated the clinical efficacy of some anti-amyloid β (Aβ) antibody therapies, such as lecanemab and donanemab. To...

Anti-Amyloid Therapies for Alzheimer's Disease: Progress, Pitfalls, and the Path Ahead. — Anti-amyloid monoclonal antibodies have finally achieved their translational breakthrough after many years of unmet expectations. The FDA granted traditional approval to lecanemab in July 2023, and the European Medicines...

Add-on combination therapy with monoclonal antibodies: Implications for drug development. — Three anti-amyloid monoclonal antibodies (MABs) including aducanumab, lecanemab, and donanemab have been approved by the FDA and lecanemab and donanemab are available in the US market and a variety of other national markets....

Recent Advances in Antibody Therapy for Alzheimer's Disease: Focus on Bispecific Antibodies. — Alzheimer's disease (AD) impacts more than half a million people worldwide, with no cure available. The regulatory approval of three anti-amyloid monoclonal antibodies (mAbs), including aducanumab, lecanemab, and...

Anti-Amyloid Monoclonal Antibodies for Alzheimer's Disease: Evidence, ARIA Risk, and Precision Patient Selection. — Alzheimer's disease (AD) is the most common cause of dementia, pathologically defined by extracellular amyloid-β (Aβ) plaques and intracellular tau neurofibrillary tangles. Recent U.S. Food and Drug...

Preparing for the implementation of anti-amyloid therapies in Europe: Assessing real-world eligibility for lecanemab and donanemab in a Swedish memory clinic. — Lecanemab and donanemab are the first anti-Aβ treatments to receive approval in Europe. Eligibility criteria are strict, eg., APOE ε4/4 carriers are...

The structural foundations of anti-amyloid-β immunotherapies: Unravelling antibody-antigen interactions in Alzheimer's disease treatment.

Radionuclide Selection Influences Imaging Outcomes in Immuno-PET with a Brain-Penetrating Anti-Amyloid-β Antibody. — Bispecific antibodies exploiting receptor-mediated transcytosis offer a promising strategy to overcome limited blood-brain barrier permeability in Alzheimer disease immunotherapy and imaging....

AI-enhanced Centiloid quantification of amyloid PET images.

FDA-Approved Passive Immunization Treatments Against Aβ in Alzheimer's Disease: Where Are We Now? — Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by decreased amyloid-beta (Aβ) clearance, enhanced Aβ aggregation, an increased risk of amyloid-related imaging abnormalities (ARIA), and...

Quantitative Amyloid Brain Imaging: A Literature Review of the Centiloid Scale in Alzheimer Disease Evaluation. — Amyloid PET has become a pivotal imaging biomarker for Alzheimer disease (AD), enabling in vivo detection and quantification of β-amyloid deposition. However, variability in quantitative measurements...

Review of Donanemab and Lecanemab in Mild Dementia Stage of Alzheimer's Disease: Progress and Challenges. — Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline and functional impairment, primarily driven by the accumulation of amyloid-beta (Aβ) plaques and tau tangles....

Safety profiles of lecanemab: A systematic review and meta-analysis of randomized controlled trials and real-world evidence.

CRISPR editing of miR-33 restores ApoE lipidation and amyloid-β metabolism in ApoE4 sporadic Alzheimer's disease. — Sporadic Alzheimer's disease (sAD) is marked by dysregulated lipid metabolism, prominently involving apolipoprotein E (ApoE). MicroRNA-33 (miR-33) has emerged as a key regulator of lipid homeostasis,...

Anti-amyloid antibody equilibrium binding to Aβ aggregates from human Alzheimer's disease brain.

Use of Model-Based Meta-Analysis to Inform the Design of Early Clinical Trials of Anti-Amyloid Beta Therapies in Alzheimer's Disease. — To inform an efficient development of new investigational anti-amyloid beta (anti-Aβ) monoclonal antibodies (mAbs), a modeling-and-simulation-based strategy was proposed. A general...

[Precautions for Neurosurgeons in Administering Anti-Amyloid β Antibody Therapy]. — In Japan, anti-amyloid β (Aβ) monoclonal antibodies, including lecanemab and donanemab, have recently been approved as disease-modifying therapies for early-stage Alzheimer's disease (AD). These drugs, developed based on the amyloid...

MRI protocols and sequences for amyloid-related imaging abnormalities monitoring in Alzheimer's disease patients treated with monoclonal antibodies. — Purpose of reviewThis review provides an updated overview of amyloid-related imaging abnormalities (ARIA) associated with antiamyloid monoclonal antibodies (mAbs) in...

Sex differences in efficacy/safety of anti-amyloid-beta monoclonal antibodies for the treatment of Alzheimer's disease. — Alzheimer's disease (AD) is the most common cause of dementia. AD exhibits notable sex-related disparities in prevalence, progression, and treatment response. With the recent approval of...

Relationship between <i>APOE</i> Genotype Status and Imaging Features in Patients with Alzheimer Disease Being Considered for Antiamyloid β Therapy.

Serious doubts about amyloid-β (Aβ) biomarkers and anti-Aβ immunotherapy. — Reports highlight new Alzheimer's disease treatments using anti-amyloid-β immunotherapy, but we see major concerns. The trials supporting lecanemab and donanemab approvals have methodological flaws, and the benefits may be smaller than the...

The minimum clinically important difference for CDR-SB in early Alzheimer's disease remains a decision-critical threshold for interpreting anti-amyloid trial effects.

A ScienceClaw-shaped runtime proposes that the anti-amyloid interpretation should remain scoped to early symptomatic disease with biomarker confirmation and MRI-capable ARIA monitoring.

A ScienceClaw-shaped artifact synthesis suggests anti-amyloid translation should be represented as a bounded benefit-risk state update, not as an unscoped efficacy claim.

Transferrin-receptor shuttle designs can increase brain exposure of anti-BACE or anti-amyloid antibodies in preclinical systems, but clinical translation remains unresolved.

Aducanumab's EMERGE and ENGAGE phase 3 trials produced discordant efficacy results, making aducanumab a contested anti-amyloid translation precedent.

What public dataset can link individual amyloid clearance, tau progression, ARIA events, and cognitive trajectories across antibody programs?

Can delivery-enhanced antibodies improve central target engagement without increasing vascular amyloid-related safety risks?

Does earlier intervention before tau spread materially change the clinical effect size of anti-amyloid therapy?

Can APOE4-specific risk models prospectively identify patients whose ARIA risk outweighs expected anti-amyloid benefit?

Which non-APP BACE1 substrates explain cognitive worsening or toxicity in failed BACE inhibitor trials?

How should anti-amyloid trial results be interpreted when amyloid PET changes substantially but CDR-SB or iADRS changes remain near clinical meaningfulness thresholds?

What trial design can distinguish amyloid lowering that is causally upstream of cognitive benefit from amyloid lowering that is an insufficient biomarker response?

Which subgroup has a benefit-risk profile large enough to justify anti-amyloid antibody treatment once ARIA, monitoring burden, and absolute cognitive effect are modeled together?

Focused ultrasound blood-brain barrier opening may increase regional amyloid removal during aducanumab treatment, but current human evidence is very small and not sufficient for clinical translation.

Which public patient-level dataset can jointly inspect amyloid clearance, tau movement, ARIA events, APOE4 status, and cognitive trajectory after anti-amyloid treatment?

Anti-TfR/BACE1 bispecific antibodies cross the blood-brain barrier and reduce brain amyloid-beta levels in human TfR knock-in mice.

If amyloid containment rather than production is the operative variable, why have anti-amyloid antibodies (e.g., lecanemab) shown any clinical benefit at all?

Failed BACE1 inhibitor trials produce a measurable, directional confidence drift in the evidence graph for the amyloid cascade hypothesis. Predictions: Confidence weights on amyloid-cascade-supporting edges will decrease following the publication dates of the failed trials.; Targets downstream of BACE1 will show...

Under which specific patient subgroups or disease stages does amyloid-targeting with lecanemab produce measurable clinical benefit?

If tau is the stronger correlate of decline, why have anti-amyloid therapies (lecanemab, donanemab) shown clinical benefit while anti-tau therapies have largely failed?

Bapineuzumab (anti-Aβ monoclonal) failed primary endpoints in two Phase III trials in mild-moderate Alzheimer's. ARIA-E vasogenic edema rate was elevated in APOE4 carriers, foreshadowing the BBB-permeability / APOE4 axis later articulated by Montagne 2020.

The reduction of brain amyloid-beta by anti-TfR/BACE1 antibodies in human TfR knock-in mice is dependent on the antibody's affinity for the transferrin receptor.

Lecanemab (anti-protofibril Aβ MAb) shows modest but statistically significant slowing of cognitive decline (CDR-SB ~0.45 point benefit at 18 months) in early symptomatic AD with PET-confirmed amyloid. First clearly positive Phase III for amyloid-cascade-as-drug-target — confidence updates upward in early-stage AD...

The Brain Shuttle version of an anti-Aβ antibody, utilizing a monovalent binding mode to the transferrin receptor (TfR), increases β-Amyloid target engagement in an Alzheimer's disease mouse model by 55-fold compared to the parent antibody.

Aducanumab (anti-Aβ monoclonal) reduces brain amyloid plaque burden dose- and time-dependently in mild-AD patients (Phase Ib PRIME trial); pilot signal of cognitive benefit at higher doses, with ARIA-E rate APOE4-dose-dependent. The Phase Ib that motivated ENGAGE/EMERGE.