Persistence Of BAN2401-Mediated Amyloid Reductions Post-treatment: A Preliminary Comparison of Amyloid Status Between the Core Phase of BAN2401-G000-201 and Baseline of the Open-Label Extension Phase in Subjects with Early Alzheimer’s Disease (1330)

Objective: To assess amyloid PET status from the first 111 subjects at baseline in the ongoing open-label extension (OLE) of BAN2401-G000-201. Background: BAN2401, a humanized IgG1 monoclonal antibody, selectively binds Aβ protofibrils over monomers (≥1000-fold) and fibrils (≥10-fold). BAN2401 treatment demonstrated brain amyloid reduction in the core phase2 study (BAN2401-G000-201), with up to 81% subjects returning on visual read from amyloid positive to negative at 18 months in the 10mg/kg-biweekly group. Design/Methods: Subjects who fulfilled OLE inclusion/exclusion criteria were eligible. All subjects were required to be amyloid positive at baseline in core study, based on PET visual read or CSF. Amyloid PET status was determined at OLE baseline. Due to timing of OLE implementation, there was no limitation on time off drug prior to entering OLE. Results: 111 subjects from the core study have undergone an amyloid PET at OLE baseline as of the cutoff for this analysis, including 84 BAN2401-treated subjects (mean duration time off study drug=23.7 months [min=9.2 months;max=52.5 months]. 80% (68/84) of all BAN2401-treated subjects from the core study were amyloid negative at OLE baseline by visual read. All amyloid-negative, BAN2401-treated subjects entering the OLE were also amyloid negative at OLE baseline (N=36;mean 32.1 months off drug). Mean core baseline PET standard uptake value ratio (SUVr) for the 10mg/kg-biweekly group in core was 1.36 (N=14). Mean PET SUVr change from core baseline to OLE Baseline (N=12; −0.29) was comparable to the mean change observed from core baseline to core 18 months treatment (N=13; −0.30), despite a mean time off study drug of 29.4 months. Conclusions: In this preliminary analysis, BAN2401-mediated returning to amyloid PET negativity by visual read persists from the end of core treatment to OLE baseline, which is consistent with PET SUVr data, despite subjects being off BAN2401 for 9 to 52 months. Disclosure: Dr. Swanson has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.Dr. Zhang has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.. Dr. Dhadda has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.Dr. Wang has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.. Dr. Kaplow has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.. Dr. Kaplow has received personal compensation in an editorial capacity for Eisai Inc.. Dr. Bradley has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.Dr. Rabe has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc.. Dr. Totsuka has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Co., Ltd.. Dr. Lai has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Ltd.. Dr. Gordon has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Ltd. Dr. Kramer has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai Inc..