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March 1989

Systemic Interferon Alfa in Multiple Sclerosis

Author Affiliations

Department of Clinical Neurological Sciences Division of Neurology University Hospital PO Box 5339 Postal Station A London, Ontario, Canada N6A 5A5

Arch Neurol. 1989;46(3):251-252. doi:10.1001/archneur.1989.00520390017007

To the Editor.  —We wish to comment on the conclusions reached by Panitch1 in his follow-up study of patients treated with subcutaneous interferon alfa. Panitch notes that patients treated with interferon alfa experienced a reduction in attack frequency from 1.33 per year to 0.47 per year over a mean follow-up of four years. He concludes that interferon treatment was associated with "a prolonged beneficial effect." We do not agree. We find nothing surprising in the decrease in the relapse rate that was observed. The author cites McAlpine and coworkers' studies2,3 that, like other retrospective studies, inadequately estimate attack frequency. The literature4 would support the notion that the observations by Panitch are entirely consistent with the natural history of multiple sclerosis (MS). Our studies on 197 patients seen from onset of MS show that the frequency of attacks in relapsing and remitting patients declined from 1.80 per year