This multicenter, randomized, double-blind, placebo-controlled, two-arm, parallel-group study will evaluate the efficacy and safety of RoActemra/Actemra (tocilizumab) in participants with systemic sclerosis. Participants will be randomized to receive either RoActemra/Actemra 162 mg subcutaneously weekly or placebo for 48 weeks. From Week 48 to Week 96, all participants will receive open-label RoActemra/Actemra 162 mg subcutaneously weekly. Anticipated time on study treatment is 96 weeks.