Delivery of the Brainshuttle™ amyloid-beta antibody fusion trontinemab to non-human primate brain and projected efficacious dose regimens in humans

An AAV capsid reprogrammed to bind human transferrin receptor mediates brain-wide gene delivery

Developing vehicles that efficiently deliver genes throughout the human central nervous system (CNS) will broaden the range of treatable genetic diseases. We engineered an adeno-associated virus (AAV) capsid, BI-hTFR1, that binds human transferrin receptor (TfR1), a protein expressed on the blood-brain barrier. BI-hTFR1 was actively transported across human brain endothelial cells and, relative to AAV9, provided 40 to 50 times greater reporter expression in the CNS of human TFRC knockin mice. The enhanced tropism was CNS-specific and absent in wild-type mice. When used to deliver GBA1, mutations of which cause Gaucher disease and are linked to Parkinson's disease, BI-hTFR1 substantially increased brain and cerebrospinal fluid glucocerebrosidase activity compared with AAV9. These findings establish BI-hTFR1 as a potential vector for human CNS gene therapy.

Passive Anti-Amyloid Beta Immunotherapies in Alzheimer's Disease: From Mechanisms to Therapeutic Impact

Alzheimer's disease, the most common type of dementia worldwide, lacks effective disease-modifying therapies despite significant research efforts. Passive anti-amyloid immunotherapies represent a promising avenue for Alzheimer's disease treatment by targeting the amyloid-beta peptide, a key pathological hallmark of the disease. This approach utilizes monoclonal antibodies designed to specifically bind amyloid beta, facilitating its clearance from the brain. This review offers an original and critical analysis of anti-amyloid immunotherapies by exploring several aspects. Firstly, the mechanisms of action of these therapies are reviewed, focusing on their ability to promote Aβ degradation and enhance its efflux from the central nervous system. Subsequently, the extensive history of clinical trials involving anti-amyloid antibodies is presented, from initial efforts using first-generation molecules leading to mixed results to recent clinically approved drugs. Along with undeniable progress, the authors also highlight the pitfalls of this approach to offer a balanced perspective on this topic. Finally, based on its potential and limitations, the future directions of this promising therapeutic strategy for Alzheimer's disease are emphasized.

Alzheimer's disease drug development pipeline: 2024

INTRODUCTION

New therapies to prevent or delay the onset of symptoms, slow progression, or improve cognitive and behavioral symptoms of Alzheimer's disease (AD) are needed.

METHODS

We interrogated clinicaltrials.gov including all clinical trials assessing pharmaceutical therapies for AD active in on January 1, 2024. We used the Common Alzheimer's Disease Research Ontology (CADRO) to classify the targets of therapies in the pipeline.

RESULTS

There are 164 trials assessing 127 drugs across the 2024 AD pipeline. There were 48 trials in Phase 3 testing 32 drugs, 90 trials in Phase 2 assessing 81 drugs, and 26 trials in Phase 1 testing 25 agents. Of the 164 trials, 34% (N = 56) assess disease-modifying biological agents, 41% (N = 68) test disease-modifying small molecule drugs, 10% (N = 17) evaluate cognitive enhancing agents, and 14% (N = 23) test drugs for the treatment of neuropsychiatric symptoms.

DISCUSSION

Compared to the 2023 pipeline, there are fewer trials (164 vs. 187), fewer drugs (127 vs. 141), fewer new chemical entities (88 vs. 101), and a similar number of repurposed agents (39 vs. 40).

Highlights

In the 2024 Alzheimer's disease drug development pipeline, there are 164 clinical trials assessing 127 drugs.The 2024 Alzheimer's disease drug development pipeline has contracted compared to the 2023 Alzheimer pipeline with fewer trials, fewer drugs, and fewer new chemical entities.Drugs in the Alzheimer's disease drug development pipeline target a wide array of targets; the most common processes targeted include neurotransmitter receptors, inflammation, amyloid, and synaptic plasticity.The total development time for a potential Alzheimer's disease therapy to progress from nonclinical studies to FDA review is approximately 13 years.

Monoclonal antibody therapy for Alzheimer's disease focusing on intracerebral targets

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Due to the complexity of the disorder and the presence of the blood-brain barrier (BBB), its drug discovery and development are facing enormous challenges, especially after several failures of monoclonal antibody (mAb) trials. Nevertheless, the Food and Drug Administration's approval of the mAb aducanumab has ushered in a new day. As we better understand the disease's pathogenesis and identify novel intracerebral therapeutic targets, antibody-based therapies have advanced over the past few years. The mAb drugs targeting β-amyloid or hyperphosphorylated tau protein are the focus of the current research. Massive neuronal loss and glial cell-mediated inflammation are also the vital pathological hallmarks of AD, signaling a new direction for research on mAb drugs. We have elucidated the mechanisms by which AD-specific mAbs cross the BBB to bind to targets. In order to investigate therapeutic approaches to treat AD, this review focuses on the promising mAbs targeting intracerebral dysfunction and related strategies to cross the BBB.

A pivotal decade for bispecific antibodies?

Bispecific antibodies (bsAbs) are a class of antibodies that can mediate novel mechanisms of action compared to monospecific monoclonal antibodies (mAbs). Since the discovery of mAbs and their adoption as therapeutic agents in the 1980s and 1990s, the development of bsAbs has held substantial appeal. Nevertheless, only three bsAbs (catumaxomab, blinatumomab, emicizumab) were approved through the end of 2020. However, since then, 11 bsAbs received regulatory agency approvals, of which nine (amivantamab, tebentafusp, mosunetuzumab, cadonilimab, teclistamab, glofitamab, epcoritamab, talquetamab, elranatamab) were approved for the treatment of cancer and two (faricimab, ozoralizumab) in non-oncology indications. Notably, of the 13 currently approved bsAbs, two, emicizumab and faricimab, have achieved blockbuster status, showing the promise of this novel class of therapeutics. In the 2020s, the approval of additional bsAbs can be expected in hematological malignancies, solid tumors and non-oncology indications, establishing bsAbs as essential part of the therapeutic armamentarium.

Current Anti-Amyloid-β Therapy for Alzheimer's Disease Treatment: From Clinical Research to Nanomedicine

Recent successive approval of anti-amyloid-β (Aβ) monoclonal antibodies as disease-modifying therapies against Alzheimer's disease (AD) has raised great confidence in the development of anti-AD therapies; however, the current therapies still face the dilemma of significant adverse reactions and limited effects. In this review, we summarized the therapeutic characteristics of the approved anti-Aβ immunotherapies and dialectically analyzed the gains and losses from clinical trials. The review further proposed the reasonable selection of animal models in preclinical studies from the perspective of different animal models of Aβ deposition and deals in-depth with the recent advances of exploring preclinical nanomedical application in Aβ targeted therapy, aiming to provide a reliable systematic summary for the development of novel anti-Aβ therapies. Collectively, this review comprehensively dissects the pioneering work of Aβ-targeted therapies and proposed perspective insight into AD-modified therapies.