Two sides of the same coin: tyrosine kinase inhibition in cancer and neurodegeneration

Emerging drugs for dementia with Lewy Bodies: a review of Phase II & III trials

INTRODUCTION

Despite faster cognitive decline and greater negative impact on patients and family caregivers, drug development efforts in Dementia with Lewy Bodies (DLB) fall behind those for Alzheimer's Disease (AD). Current off-label drug DLB treatment options are limited to symptomatic agents developed to address cognitive deficits in AD, motor deficits in Parkinson's Disease, or behavioral symptoms in psychiatric disease. Aided by recent improvements in DLB diagnosis, a new focus on the development of disease-modifying agents (DMA) is emerging.

AREAS COVERED

Driven by evidence supporting different pathological mechanisms in DLB and PDD, this review assesses the evidence on symptomatic drug treatments and describes current efforts in DMA development in DLB. Specifically, our goals were to: (1) review evidence supporting the use of symptomatic drug treatments in DLB; (2) review the current DMA pipeline in DLB with a focus on Phase II and III clinical trials; and (3) identify potential issues with the development of DMA in DLB. Included in this review were completed and ongoing drug clinical trials in DLB registered on ClinicalTrials.gov (no time limits set for the search) or disseminated at the 2023 international conference on Clinical Trials in AD. Drug clinical trials registered in non-US clinical trial registries were not included.

EXPERT OPINION

Adoption of current symptomatic drug treatments used off-label in DLB relied on efficacy of benefits in other disorders rather than evidence from randomized controlled clinical trials. Symptoms remain difficult to manage. Several DMA drugs are currently being evaluated as either repurposing candidates or novel small molecules. Continued improvement in methodological aspects including development of DLB-specific outcome measures and biomarkers is needed to move the field of DMA drug development forward.

RENEWAL: REpurposing study to find NEW compounds with Activity for Lewy body dementia-an international Delphi consensus

Drug repositioning and repurposing has proved useful in identifying new treatments for many diseases, which can then rapidly be brought into clinical practice. Currently, there are few effective pharmacological treatments for Lewy body dementia (which includes both dementia with Lewy bodies and Parkinson's disease dementia) apart from cholinesterase inhibitors. We reviewed several promising compounds that might potentially be disease-modifying agents for Lewy body dementia and then undertook an International Delphi consensus study to prioritise compounds. We identified ambroxol as the top ranked agent for repurposing and identified a further six agents from the classes of tyrosine kinase inhibitors, GLP-1 receptor agonists, and angiotensin receptor blockers that were rated by the majority of our expert panel as justifying a clinical trial. It would now be timely to take forward all these compounds to Phase II or III clinical trials in Lewy body dementia.

Current Therapies and Drug Development Pipeline in Lewy Body Dementia: An Update

The term Lewy body dementia refers to either of two related diagnoses: dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Clinical management of Lewy body dementia is challenging. The current treatment options focus on relieving symptoms; no disease-modifying therapies are available. There are currently no US Food and Drug Administration (FDA) approved drugs for the treatment of DLB, and there are only a few for PDD. Cholinesterase inhibitors are shown to be beneficial in improving cognitive symptoms in Lewy body dementia. Rivastigmine was approved by the FDA to treat PDD. Donepezil was approved in Japan as a treatment for DLB. Levodopa may provide modest benefit in treating motor symptoms and zonisamide in adjunct to low-dose levodopa helps with parkinsonism. Treatment of autonomic symptoms are based on symptomatic treatment with off-label agents. Our main objective in this article is to present an overview of the current pharmacological options available to treat the clinical features of DLB and PDD. When evaluating the existing management options for Lewy body dementia, it is difficult to fully separate PDD from DLB. However, we have attempted to identify whether the cited studies include patients with PDD and/or DLB. Moreover, we have provided an overview of the current drug pipeline in Lewy body dementia. All currently active trials are in phase I or II and most are focused on disease modification rather than symptomatic treatment. Phase II trial results for neflamapimod show promising results. Due to heterogeneity of symptoms and underlying pathophysiology, there is a need for new biomarker strategies and improved definitions of outcome measures for Lewy body dementia drug trials.

Phosphotyrosine profiling of human cerebrospinal fluid

Background

Cerebrospinal fluid (CSF) is an important source of potential biomarkers that affect the brain. Biomarkers for neurodegenerative disorders are needed to assist in diagnosis, monitoring disease progression and evaluating efficacy of therapies. Recent studies have demonstrated the involvement of tyrosine kinases in neuronal cell death. Thus, neurodegeneration in the brain is related to altered tyrosine phosphorylation of proteins in the brain and identification of abnormally phosphorylated tyrosine peptides in CSF has the potential to ascertain candidate biomarkers for neurodegenerative disorders.

Methods

In this study, we used an antibody-based tyrosine phosphopeptide enrichment method coupled with high resolution Orbitrap Fusion Tribrid Lumos Fourier transform mass spectrometer to catalog tyrosine phosphorylated peptides from cerebrospinal fluid. The subset of identified tyrosine phosphorylated peptides was also validated using parallel reaction monitoring (PRM)-based targeted approach.

Results

To date, there are no published studies on global profiling of phosphotyrosine modifications of CSF proteins. We carried out phosphotyrosine profiling of CSF using an anti-phosphotyrosine antibody-based enrichment and analysis using high resolution Orbitrap Fusion Lumos mass spectrometer. We identified 111 phosphotyrosine peptides mapping to 66 proteins, which included 24 proteins which have not been identified in CSF previously. We then validated a set of 5 tyrosine phosphorylated peptides in an independent set of CSF samples from cognitively normal subjects, using a PRM-based targeted approach.

Conclusions

The findings from this deep phosphotyrosine profiling of CSF samples have the potential to identify novel disease-related phosphotyrosine-containing peptides in CSF.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9205-1) contains supplementary material, which is available to authorized users.

Interplay of autophagy, receptor tyrosine kinase signalling and endocytic trafficking

Vesicular trafficking events play key roles in the compartmentalization and proper sorting of cellular components. These events have crucial roles in sensing external signals, regulating protein activities and stimulating cell growth or death decisions. Although mutations in vesicle trafficking players are not direct drivers of cellular transformation, their activities are important in facilitating oncogenic pathways. One such pathway is the sensing of external stimuli and signalling through receptor tyrosine kinases (RTKs). The regulation of RTK activity by the endocytic pathway has been extensively studied. Compelling recent studies have begun to highlight the association between autophagy and RTK signalling. The influence of this interplay on cellular status and its relevance in disease settings will be discussed here.