Powerful stuff. Undertreat it and the patient dies. Today, most regimens are based around cyclophosphamide, and there are a host of other agents. I suspect that these work largely by lowering the neutrophil count, since these are the cells against which the immunity is actually directed. http://emedicine.medscape.com/article/332622-treatment is pretty good, the alternate name is because Wegener was German in WW2.
Several. It really depends on the areas involved and the severity of that involvement. Limited disease can often be treated with Methotrexate with or without low dose prednisone. For more significant disease Rituxan (rituximab) is very helpful. Major kidney or neurologic involvement may require initial treatment with Cytoxan or similar agents.