A trial of cyclophosphamide in ankylosing spondylitis with involvement of peripheral joints and high disease activity.

In 12 patients with ankylosing spondylitis with involvement of the peripheral joints and high activity of the disease process, cyclophosphamide was given in intravenous doses of 200 mg every second day for 3 weeks, followed by oral doses of 100 mg once weekly for 3 months to a total dose of 3 300 mg. Before this treatment and after 18-24 months the following clinical parameters were determined: spinal mobility, degree of intensity of spinal and articular pains, and the number of involved joints. After the treatment an evident clinical improvement was observed, with decreased values of the laboratory indices of the disease activity. Apart moderate erythrocyturia in one case and transient leukopenia in another case, no other side effects were observed. The improvement in cases with coexistent amyloidosis was relatively small.