Mallinckrodt plc said it plans to acquire Infacare Pharmaceutical Corp., the developer of a late-stage severe jaundice treatment, for $80 million up front plus up to $345 million in potential milestone payments. If approved, the FDA fast-tracked candidate, stannsoporfin, could potentially be used to reduce or prevent the need for phototherapy, risky exchange transfusions and the incidence of pricey hospital readmissions.