During the Screening Phase, eligible ALS subjects will sign an informed consent form and the following screening assessments will be performed: review of inclusion/exclusion criteria: El Escorial ALS Diagnostic criteria, medical history and demographics, ALS diagnosis history, physical and neurological examination, U. Penn upper motor Neuron Burden (UMNB), pulmonary function tests, vital signs including height and weight, blood for safety labs including TSPO affinity test, ECG and review and documentation of concomitant medications and therapies.