Failure of other Tx. Apls (antiphospholipid antibody syndrome) if necessary can be treated first with steroids like prednisone. Sometimes just being on a blood thinner is enough to avoid blood clots that it can cause or miscarriages. Other treatments like Rituxan (rituximab) (antibody) have been used especially if low platelet counts are seen. If these initial tx fail, doctors may resort to chemo drugs like cyclophosphamide.
When it causes bad blood clots. The antiphospholipid syndrome is one of several types of hypercoagulability. It can cause dvts, pulmonary emboli, and strokes. When it is bad like this, it is often treated with anticoagulants like coumadin (warfarin).