Cognitive outcomes of anti‐amyloid‐β monoclonal antibodies in patients with Alzheimer's disease: A systematic review and meta‐analysis of randomized controlled trials

Abstract

AbstractBackgroundFor the last 20 years, the amyloid‐beta (Aβ) cascade hypothesis has been dominant in the research of disease‐modifying therapeutics, with spent of financial and clinical resources in potential drugs targeting Aβ peptide production or clearance. (1) In this context, monoclonal antibodies targeting beta‐amyloid (Aβ‐mAbs) are being tested to reduce the amyloid burden in patients with Alzheimer’s Disease (AD). (2) However, the cognitive impact of Aβ‐mAbs remains controversial. (3) We aim to evaluate the conflicting results of previous studies using a meta‐analysis.MethodWe searched PubMed, Embase, and Cochrane databases, following until April 2021, using the search terms: ''Alzheimer's disease'' OR ''dementia'' cross‐referenced with ''monoclonal antibodies'', considering the synonyms. Eligible articles were randomized clinical trials with Aβ‐mAbs that reported cognitive outcomes. The cognitive function was assessed by Alzheimer’s Disease Assessment Scale (ADAS‐cog) and Mini‐Mental State‐Exam (MMSE). We performed a meta‐analysis comparing mAbs and placebo, considering a minimal significant clinical change of 3 points in ADAS‐Cog and 2 points in MMSE.ResultWe found 12 eligible studies in 443 identified records, involving 6736 patients, mean age 71.4 ± 2. We found a small benefit in cognitive outcomes in patients treated with Aβ‐mAbs: ADAS‐Cog: mean difference (MD) = ‐ 0.65; 95% CI (‐1.05 to ‐ 0.26); I² = 12%; (p = 0.001) and MMSE: MD = 0.40; 95% CI (0.18 to 0.63); I² = 10%; (p = 0.0004). The Funnel plot and Egger’s test did not show publication bias. MD was below the minimal clinically relevant change in both scales.ConclusionAβ‐mAbs may have a positive cognitive benefit in AD patients. However, the impact magnitude is small, not reaching minimal clinically relevant change for these scales.