Acumen Pharmaceuticals Inc. has announced the dosing of the first participant in the open-label extension (OLE) phase of its Phase 2 ALTITUDE-AD clinical trial evaluating sabirnetug (ACU193) in individuals with early Alzheimer's disease. This extension allows participants who completed the initial 18-month placebo-controlled portion to receive sabirnetug at 35 mg/kg intravenously every four weeks for an additional 52 weeks. The study will continue to monitor clinical measures and safety. Sabirnetug is a humanized monoclonal antibody targeting soluble amyloid beta oligomers. Topline results from the ALTITUDE-AD trial are expected to be reported in late 2026.