Have primary progressive multiple sclerosis (MS)

Have secondary progressive MS without superimposed relapses

Relevant cardiac, hepatic and renal diseases as specified in the protocol

Pretreatment with immunosuppressants and immunomodulating drugs as specified in the protocol

Clinical significant abnormalities in blood cell counts and immunoglobulin levels as specified in the protocol

A Phase 2 Study of Atacicept in Subjects With Relapsing Multiple Sclerosis (ATAMS)