A Phase 3, Randomized, Double-blind, Placebo-controlled Study to Assess the Efficacy and Safety of Sutimlimab in Patients With Primary Cold Agglutinin Disease Without a Recent History of Blood Transfusion

Experimental: BIVV009/BIVV009

Participants with primary CAD and without a recent history of blood transfusion during the last 6 months prior to enrollment in this study, received an intravenous (IV) infusion of BIVV009 6.5 g (for participants less than \[\<\]75 kilograms \[kg\]) or 7.5 g dose (for participants greater than or equal to \[\>=\]75 kg) on Day 0 and Day 7 and every 14 days thereafter in Part A up to Week 25. Participants who completed Part A per protocol through the end of treatment visit (Week 26), received placebo on Week 26 and continued to receive BIVV009 6.5 or 7.5 g in Part B, every 2 weeks starting at Week 27 for up to an additional 149 weeks (for 6.5 g) or 121 weeks (for 7.5 g). All participants who completed Part A elected to continue in Part B.

Experimental: Placebo/BIVV009

Participants with primary CAD and without a recent history of blood transfusion during the last 6 months prior to enrollment in this study, received an IV infusion of placebo matched to BIVV009 on Day 0 and Day 7 and every 14 days thereafter in Part A up to Week 25. Participants who completed Part A per protocol through the end of treatment visit (Week 26) received BIVV009 6.5 (if \<75 kg) or 7.5 g (if \>=75 kg) in Part B, on Week 26 and Week 27 and every 2 weeks thereafter for up to an additional 123 weeks (for 6.5 g) or 137 weeks (for 7.5 g). All participants who completed Part A elected to continue in Part B.