A Study Evaluating the Safety and Efficacy of Rituximab in Combination With Glucocorticoids in Participants With Wegener's Granulomatosis or Microscopic Polyangitis

Methyprednisolone will be administered 1 to 3 pulses at a dose of 1000 milligram (mg) IV at the discretion of the investigator.

Prednisone will be administered orally at tapered dose (start at 1 milligrams per kilogram per day \[mg/kg/day\]) at the discretion of investigator given daily until participants are off the drug.

Rituximab will be administered at 375 milligrams per meter square (mg/m\^2) of body surface area given by IV infusion once weekly from Week 1 to 4.