#Pfizer Inc. ( $PFE ) Global Multiple Sclerosis Drugs Market Study, 2020 - Leading Players are #Biogen, #Novartis, #Roche, #Bayer HealthCare, Pfizer, #Merck &amp; Co, #Sanofi, #Teva Pharma, #GlaxoSmithKline and #Acorda Therapeutics