ARO-MAPT is an experimental RNA interference (RNAi) drug from Arrowhead Pharmaceuticals, given as an injection under the skin, that is designed to silence the MAPT gene in the brain and so reduce production of tau, a protein that clumps into tangles in Alzheimer’s disease and related disorders called tauopathies.
In interim Phase 1/2a results announced on 14 October 2026, healthy volunteers who received the highest dose (12.8 mg/kg on days 1 and 15) had a mean 73% drop in total tau in their cerebrospinal fluid at day 105, 90 days after the last dose, with a maximum individual reduction of 85%; lower doses gave mean reductions of 40% and 69%. The drug was generally well tolerated, with mostly mild side effects and no serious treatment-related events reported. These are biomarker results in healthy people only; whether the drug slows memory loss or disease progression is still being tested in people with early Alzheimer’s disease, with data expected in 2027.
Source: Arrowhead Pharmaceuticals — ARO-MAPT interim Phase 1/2a clinical data (14 Oct 2026)
Image: Illustration of healthy and diseased neurons showing tau proteins detaching from microtubules and forming tangles. Credit: National Institute on Aging (ADEAR), public domain, via Wikimedia Commons.