Researchers assessed 15 patients with MS who underwent monthly MRIs and clinical examinations during a six-month pretreatment phase and 36-month treatment phase.
During treatment patients received injections of 250 micrograms of interferon beta under the skin every other day.
MRI scans every six months showed eight patients achieved a 60% reduction in the number brain lesions and were classified as responders.
Of the seven non-responders, three initially experienced a reduction in the total number of lesions but then did not experience further reductions, two never reached the 60% level of reduction and two failed to respond during the first six months but reached and maintained an optimal reduction in lesions of 60% or more or thereafter.
Three patients in the responder group and all seven patients in the non-responder group experienced at least on clinical exacerbation during the treatment phase.
Authors wrote: ‘To our knowledge, our descriptive study provides for the first time a detailed long-term analysis of MRI patterns of patients undergoing long-term interferon beta-1b therapy,” the authors conclude. “The results show that on close monthly MRI inspection, approximately half of the patients fail therapy from an MRI perspective.’
Archives of Neurology (2009) published online first.