Photopheresis for Rheumatoid Arthritisa

Abstract

For rheumatoid arthritis, an effective therapy with minimal toxicity would be welcome. In a six-month pilot study of seven patients with a variety of presentations and previous treatments, we tested a therapy involving the extracorporeal photoactivation of biologically inert methoxsalen (8-methoxypsoralen) by ultraviolet A energy to a form that covalently cross-links lymphocyte DNA; the injured cells are returned to the patient. Prior experimental studies had indicated that this regimen produces an immune reaction against antigens on treated T Cells, and a clinical trial in cutaneous T cell lymphoma had been successful. The current patients were treated on two successive days monthly (or, later on, biweekly). Between 12 and 16 weeks of therapy there appeared to be a breakpoint after which joint counts and joint scores of four patients began to improve. In three of them, these measures eventually diminished by mean values of 71% and 80%, respectively, of their baseline values, along with variable improvement in less direct indicators of clinical response. The joints of the fourth patient improved modestly (by 33% and 59%, respectively, of baselines) but he required alternative therapy, and those of the remaining three patients did not improve. Mean slopes for the joint counts were significantly different from zero after the apparent breakpoint (but not before), whether one examined the four apparent responders (p = 0.01) or the entire group of seven (p = 0.01). After completion of therapy, there was also a delay, of two to three months, in the clinical deterioration of those who had improved. There was only one mechanical adverse effect--a single episode of transient hypotension in 102 treatment sessions--and no toxic ones. This preliminary study suggests that extracorporeal photochemotherapy may be effective at least in the short term in certain patients with rheumatoid arthritis, with less apparent toxicity than that of any of the drugs currently used for this disorder. It deserves further evaluation.