The aging of the global population anticipated the current marked increase in people with Alzheimer's disease (AD). The 2019 Alzheimer Europe Yearbook reported that the number of people with dementia in Europe will almost double by 2050. Recent progress has been made in the development and approval of disease-modifying therapies (DMTs) and symptomatic treatments for neuropsychiatric syndromes of AD. Two DMTs, aducanumab and lecanemab, have recently been approved by the US Food and Drug Administration (FDA) and another, donanemab, is currently under review. In Europe, the European Medicine Agency (EMA) is currently reviewing lecanemab and donanemab. On 24 April, the annual pipeline report, led by Dr. Jeffrey Cummings, was published in Alzheimer’s & Dementia: Translational Research and Clinical Interventions, a journal of the Alzheimer’s Association.
The goal of this report was to spot trends in clinical trial design and outcome measures and also to investigate the types of agents and biological targets that are being pursued. Researchers used data from clinicaltrials.gov, including all current phase 1, 2 and 3 clinical drug trials for AD and Mild Cognitive Impairment, as of 1 January 2024. In this report, authors did not include trials of non-pharmacologic therapeutic approaches such as exercise trials and lifestyle interventions. In total, there were 164 trials assessing 127 drugs, 48 trials in Phase 3, 90 trials in Phase 2 and 26 trials in Phase 1. 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.
Most of the drugs in the AD drug development pipeline are DMTs. In total there are 96 DMTs representing 76% of drugs in clinical trials. Considered together all current trials require 51,398 participants. DMTs account of 79% of all participants required for current trials. On average, it takes 2.1 years to recruit the populations for a Phase 1 trial, 2.5 years to recruit enough participants for a Phase 2 trial, and 3.2 years for recruitment of participants for a Phase 3 trial. Authors noted that the approval of DMTs may affect recruitment if patients choose approved over experimental therapies. 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).