Roadmap to implementation of a fully automated blood‐based biomarker test to facilitate diagnosis and treatment in early Alzheimer’s disease

Abstract

AbstractBackgroundRoutine implementation of a fully automated blood based biomarker (BBBM) will expand access to diagnosis and initiation of disease modifying therapies (DMTs) in Alzheimer’s disease (AD). This analysis explores current obstacles in the AD diagnostic pathway, the unmet need for a BBBM test to facilitate referral decisions, and barriers to BBBM testing.MethodData are from quantitative (n=1,694 physicians) and qualitative (n=186 healthcare professionals/payers) surveys in US/China/UK/Germany/Spain and two Advisory Boards (US/Europe). Primary care physicians (PCPs) and specialists (neurologists/geriatricians/psychiatrists) were represented.ResultFrom the quantitative survey, between 17.8% (China) and 83.5% (France) patients with cognitive impairment present first to primary care, with the rest presenting directly to secondary care. 73% PCPs use cognitive assessment alone for referral, with 35% using laboratory results. Confirmatory testing with positron‐emission tomography (PET) or cerebrospinal fluid (CSF) analysis is rare in the primary care setting. PCPs request PET and CSF for 8% and 12% patients, respectively, compared with 40% and 36% for specialist neurologists. Most centers use local guidelines to decide CSF/PET referral. 31% of patients diagnosed with AD underwent CSF/PET. Time to clinical diagnosis varies between countries and pathways, from 14 weeks in primary care to 29 weeks for patients referred to a specialist.The Advisory Board considered a minimally‐invasive, patient‐friendly BBBM with high negative predictive value (NPV > 90%) and moderate positive predictive value for Ab positivity could act as triage, excluding patients not needing confirmatory testing, while freeing capacity and allowing timely intervention for all others. The BBBM test would be useful in primary and secondary care, although payer coverage in primary care may limit its immediate use. In secondary care, the BBBM test could reduce unnecessary/invasive amyloid testing, and streamline the diagnostic pathway.ConclusionAn easy‐to‐use, minimally invasive BBBM test that detects amyloid pathology could be used with other tests/assessments to guide further diagnostic procedures or onward referral, reducing time to diagnosis and allowing timely access to potential DMTs. BBBMs have potential to be a first biomarker test, providing early‐stage information on underlying pathophysiology.