Split and simplify the following sentence while retaining its full meaning: Patients received two 1000 mg intravenous infusions of MabThera , each following an intravenous infusion of 100 mg methylprednisone and separated by an interval of 15 days .
 Simplified version:
The patients received two 1000 mg intravenous infusions of MabThera , 15 days apart . These infusions were each preceded by an intravenous infusion of 100 mg of methylprednisolone .