C2N 8E12 (ABBV-8E12) is a monoclonal IgG4 antibody derived from a mouse antibody (HJ8.5), that blocked tau propagation in vitro, with an epitope mapped to N-terminal amino acids 25-30. It was developed by C2N Diagnostics and AbbVie and moved into clinical trials based on preclinical data in P301S transgenic mouse models showing reduction in tau aggregation and rescue of cognitive deficits. [105-107] A Phase 1 study in 32 PSP patients showed C2N 8E12 was well-tolerated without development of ADA [108], prompting a follow-up Phase 2 efficacy study (NCT02985879) treating 378 PSP patients for 12 months, but in July 2019, AbbVie terminated the trial after it tailed an interim futility analysis. In a separate trial, 453 early AD patients are being treated for 96 weeks with safety and CDR as primary endpoints, and several clinical biomarkers as secondary endpoints, was planned to end summer 2021.
