Phase 1 Studies of the Anti-Tau Monoclonal Antibody JNJ-63733657 in Healthy Participants and Participants with Alzheimer's Disease.

Background: JNJ-63733657 (posdinemab) is a humanized IgG1/kappa monoclonal anti-phospho tau antibody that binds with high affinity to phosphorylated amino acid 217 (pT217) in the proline-rich domain. The parent molecule, PT3, was raised against Alzheimer's disease brain purified paired helical filament, and preclinical studies with the humanized version, JNJ-63733657, have demonstrated reductions in tau seeding. The results of the first-in-human clinical trial of JNJ-63733657 and a separate single ascending dose study in Japanese participants are presented.

Targeting Endogenous Tau in Seeded Tauopathy Models Inhibits Tau Spread.

The transmission of tau pathology has been proposed as one of the major mechanisms for the spatiotemporal spreading of tau pathology in neurodegenerative diseases. Over the last decade, studies have demonstrated that targeting total or pathological tau using tau antibodies can mitigate the development of tau pathology in tauopathy or Alzheimer's disease (AD) mouse models, and multiple tau immunotherapy agents have progressed to clinical trials. Tau antibodies are believed to inhibit the internalization of pathologic seeds and/or block seed elongation after seed internalization.

Anti-tau intrabodies: From anti-tau immunoglobulins to the development of functional scFv intrabodies.

Over the last decade, there has been a growing interest in intrabodies and their therapeutic potential. Intrabodies are antibody fragments that are expressed inside a cell to target intracellular antigens. In the context of intracellular protein misfolding and aggregation, such as tau pathology in Alzheimer's disease, intrabodies have become an interesting approach as there is the possibility to target early stages of aggregation.

Development and Characterization of Mouse-Specific Anti-Tau Monoclonal Antibodies: Relevance for Analysis of Murine Tau in Cerebrospinal Fluid.

Background: Clearance of tau seeds by immunization with tau antibodies is currently evaluated as therapeutic strategy to block the spreading of tau pathology in Alzheimer's disease and other tauopathies. Preclinical evaluation of passive immunotherapy is performed in different cellular culture systems and in wild-type and human tau transgenic mouse models. Depending on the preclinical model used, tau seeds or induced aggregates can either be of mouse, human or mixed origin.

Development of immunoprecipitation - two-dimensional liquid chromatography - mass spectrometry methodology as biomarker read-out to quantify phosphorylated tau in cerebrospinal fluid from Alzheimer disease patients.

In Alzheimer's disease (AD) brain, one of the histopathological hallmarks is the neurofibrillary tangles consisting of aggregated and hyperphosphorylated tau. Currently many tau binding antibodies are under development to target the extracellular species responsible for the spreading of the disease in the brain. As such, an in-house developed antibody JNJ-63733657 with picomolar affinity towards tau phosphorylated at both T212 and T217 (further named p217+tau) was recently tested in phase I clinical trial NCT03375697.

Development and validation of a high-sensitivity assay for measuring p217+tau in plasma.

Introduction: Diagnosis of Alzheimer's disease (AD) based on amyloid beta (A), pathologic tau (T), and neurodegeneration (N) biomarkers in peripheral fluids promises to accelerate clinical trials and intercept disease earlier.

Methods: Qualification of a Simoa plasma p217+tau assay was performed, followed by clinical utility evaluation in a cohort of 227 subjects with broad A and T spectrum.

Results: The p217+tau plasma assay was accurate, precise, dilution linear, and highly sensitive.

Passive immunotherapy with a novel antibody against 3pE-modified Aβ demonstrates potential for enhanced efficacy and favorable safety in combination with BACE inhibitor treatment in plaque-depositing mice.

The imbalance between production and clearance of amyloid β (Aβ) peptides and their resulting accumulation in the brain is an early and crucial step in the pathogenesis of Alzheimer's disease (AD). Therefore, Aβ is strongly positioned as a promising and extensively validated therapeutic target for AD. Investigational disease-modifying approaches aiming at reducing cerebral Aβ concentrations include prevention of de novo production of Aβ through inhibition of β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and clearance of Aβ deposits via passive Aβ immunotherapy.

Comparison of size distribution and (Pro249-Ser258) epitope exposure in in vitro and in vivo derived Tau fibrils.

Background: Although several studies demonstrate prion-like properties of Tau fibrils, the effect of size in the seeding capacity of these aggregates is not fully understood. The aim of this study is to characterize Tau seeds by their size and seeding capacity.

Methods: Tau aggregates were isolated from postmortem AD brain tissue and separated from low molecular weight species by sucrose gradient ultracentrifugation.

Discovery and Functional Characterization of hPT3, a Humanized Anti-Phospho Tau Selective Monoclonal Antibody.

Background: As a consequence of the discovery of an extracellular component responsible for the progression of tau pathology, tau immunotherapy is being extensively explored in both preclinical and clinical studies as a disease modifying strategy for the treatment of Alzheimer's disease.

Objective: Describe the characteristics of the anti-phospho (T212/T217) tau selective antibody PT3 and its humanized variant hPT3.

Methods: By performing different immunization campaigns, a large collection of antibodies has been generated and prioritized.

Decreased Deposition of Beta-Amyloid 1-38 and Increased Deposition of Beta-Amyloid 1-42 in Brain Tissue of Presenilin-1 E280A Familial Alzheimer's Disease Patients.

Familial Alzheimer's Disease (FAD) caused by Presenilin-1 (PS1) mutations is characterized by early onset, cognitive impairment, and dementia. Impaired gamma secretase function favors production of longer beta-amyloid species in PS1 FAD. The PS1 E280A mutation is the largest FAD kindred under study.

Development and Validation of a High Sensitivity Assay for Measuring p217 + tau in Cerebrospinal Fluid.

Background: Early and accurate detection and staging is critical to managing Alzheimer's disease (AD) and supporting clinical trials. Cerebrospinal fluid (CSF) biomarkers for amyloid-β peptides, tau species, and various neurodegenerative and inflammatory analytes are leading the way in this regard, yet there is room for improved sensitivity and specificity. In particular tau is known to be present in many different fragments, conformations, and post-translationally modified forms.

Central sensitization of nociceptive pathways demonstrated by robot-controlled pinprick-evoked brain potentials.

Objective: The aim of this study was to assess the effect of central sensitization, induced by high frequency electrical stimulation of the skin (HFS), on pinprick-evoked brain potentials (PEPs) using robot-controlled mechanical pinprick stimulation and a stimulus evaluation task.

Methods: In 16 healthy volunteers HFS was applied to the right volar forearm. Robot- controlled pinprick stimuli (64 mN) were applied before and 20 minutes after HFS to the skin surrounding the area onto which HFS was applied.

Cerebrospinal fluid p-tau217 performs better than p-tau181 as a biomarker of Alzheimer's disease.

Cerebrospinal fluid (CSF) p-tau181 (tau phosphorylated at threonine 181) is an established biomarker of Alzheimer's disease (AD), reflecting abnormal tau metabolism in the brain. Here we investigate the performance of CSF p-tau217 as a biomarker of AD in comparison to p-tau181. In the Swedish BioFINDER cohort (n = 194), p-tau217 shows stronger correlations with the tau positron emission tomography (PET) tracer [F]flortaucipir, and more accurately identifies individuals with abnormally increased [F]flortaucipir retention.

Design and synthesis of a novel series of cyanoindole derivatives as potent γ-secretase modulators.

The discovery, design and synthesis of a new series of GSMs is described. The classical imidazole heterocycle has been replaced by a cyano group attached to an indole nucleus. The exploration of this series has led to compound 26-S which combined high in vitro and in vivo potency with an acceptable drug-like profile.

Extracellular interface between APP and Nicastrin regulates Aβ length and response to γ-secretase modulators.

γ-Secretase complexes (GSECs) are multimeric membrane proteases involved in a variety of physiological processes and linked to Alzheimer's disease (AD). Presenilin (PSEN, catalytic subunit), Nicastrin (NCT), Presenilin Enhancer 2 (PEN-2), and Anterior Pharynx Defective 1 (APH1) are the essential subunits of GSECs. Mutations in PSEN and the Amyloid Precursor Protein (APP) cause early-onset AD GSECs successively cut APP to generate amyloid-β (Aβ) peptides of various lengths.

Anti-Tau Monoclonal Antibodies Derived from Soluble and Filamentous Tau Show Diverse Functional Properties in vitro and in vivo.

The tau spreading hypothesis provides rationale for passive immunization with an anti-tau monoclonal antibody to block seeding by extracellular tau aggregates as a disease-modifying strategy for the treatment of Alzheimer's disease (AD) and potentially other tauopathies. As the biochemical and biophysical properties of the tau species responsible for the spatio-temporal sequences of seeding events are poorly defined, it is not yet clear which epitope is preferred for obtaining optimal therapeutic efficacy. Our internal tau antibody collection has been generated by immunizations with different tau species: aggregated- and non-aggregated tau and human postmortem AD brain-derived tau fibrils.

Enhancement of therapeutic potential of a naturally occurring human antibody targeting a phosphorylated Ser containing epitope on pathological tau.

Aggregation of tau protein and spreading of tau aggregates are pivotal pathological processes in a range of neurological disorders. Accumulating evidence suggests that immunotherapy targeting tau may be a viable therapeutic strategy. We have previously described the isolation of antibody CBTAU-22.

Mass spectrometric characterization of intact desferal-conjugated monoclonal antibodies for immuno-PET imaging.

Rationale: Immuno-PET imaging may prove to be a diagnostic and progression/intervention biomarker for Alzheimer's disease (AD) with improved sensitivity and specificity. Immuno-PET imaging is based on the coupling of an antibody with a chelator that captures a radioisotope thus serving as an in-vivo PET ligand. A robust and quality controlled process for linking the chelator to the-antibody is fundamental for the success of this approach.

A common antigenic motif recognized by naturally occurring human V5-51/V4-1 anti-tau antibodies with distinct functionalities.

Misfolding and aggregation of tau protein are closely associated with the onset and progression of Alzheimer's Disease (AD). By interrogating IgG memory B cells from asymptomatic donors with tau peptides, we have identified two somatically mutated V5-51/V4-1 antibodies. One of these, CBTAU-27.

Alzheimer's-Causing Mutations Shift Aβ Length by Destabilizing γ-Secretase-Aβn Interactions.

Alzheimer's disease (AD)-linked mutations in Presenilins (PSEN) and the amyloid precursor protein (APP) lead to production of longer amyloidogenic Aβ peptides. The shift in Aβ length is fundamental to the disease; however, the underlying mechanism remains elusive. Here, we show that substrate shortening progressively destabilizes the consecutive enzyme-substrate (E-S) complexes that characterize the sequential γ-secretase processing of APP.

BACE1 Dynamics Upon Inhibition with a BACE Inhibitor and Correlation to Downstream Alzheimer's Disease Markers in Elderly Healthy Participants.

The β-site amyloid-β protein precursor (AβPP) cleaving enzyme-1 (BACE1) is the rate limiting enzyme in the generation of amyloid-β peptide (Aβ) from AβPP, one of the major pathways in Alzheimer's disease (AD) pathology. Increased BACE1 levels and activity have been reported in the brain of patients with sporadic AD. Therefore, changes of BACE1 levels in the cerebrospinal fluid (CSF) have also been investigated as a possible biomarker of the disease.

Profiling the dynamics of CSF and plasma Aβ reduction after treatment with JNJ-54861911, a potent oral BACE inhibitor.

Objectives: Safety, tolerability, pharmacokinetics, and pharmacodynamics of a novel β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor, JNJ-54861911, were assessed after single and multiple dosing in healthy participants.

Methods: Two randomized, placebo-controlled, double-blind studies were performed using single and multiple ascending JNJ-54861911 doses (up to 14 days) in young and elderly healthy participants. Regular blood samples and frequent CSF samples, up to 36 hours after last dose, were collected to assess the pharmacokinetic and pharmacodynamic (Aβ, sAPPα,β,total levels) profiles of JNJ-54861911.

Restricted Location of PSEN2/γ-Secretase Determines Substrate Specificity and Generates an Intracellular Aβ Pool.

γ-Secretases are a family of intramembrane-cleaving proteases involved in various signaling pathways and diseases, including Alzheimer's disease (AD). Cells co-express differing γ-secretase complexes, including two homologous presenilins (PSENs). We examined the significance of this heterogeneity and identified a unique motif in PSEN2 that directs this γ-secretase to late endosomes/lysosomes via a phosphorylation-dependent interaction with the AP-1 adaptor complex.