RecruitingPhase 2Drug trialA Study of Nasal Foralumab in Non-Active Secondary Progressive Multiple Sclerosis PatientsForalumab is a human anti-CD3 monoclonal antibody being developed for the treatment of autoimmune and inflammatory diseases. The goal of this Phase 2a, randomized, double-blind placebo-controlled, multicenter dose-ranging study is to evaluate the use of nasal foralumab in patients with non-active secondary progressive multiple sclerosis (SPMS). The primary objectives that this study aims to answer are: 1. To determine the safety and tolerability of 50 μg/dose and 100 μg/dose of foralumab nasal compared to placebo 2. To investigate the effect of foralumab relative to placebo on the change from baseline \[18F\]PBR06-positron emission tomography (PET) scans for microglial activation, after 12 weeks (3) months of study treatment.