089 R-CP chemoimmunotherapy in IgM paraproteinaemic neuropathy produces improvements in serological, neurological and neurophysiological outcomes

There is ongoing debate as to the optimum treatment for IgM paraproteinaemic neuropathy, although there is accumulating evidence that rituximab benefits a proportion of patients. We present a case series of 18 patients with IgM paraproteinaemic neuropathy treated with standard R-CP (rituximab, cyclophos- phamide, prednisolone) chemoimmunotherapy. 13 patients were positive for anti-MAG (myelin associ- ated glycoprotein) antibody. The remaining five had a clinical phenotype suggesting that their IgM paraprotein was causative in their neuropathy. Detailed neurological, neurophysiological and serological outcome data were recorded 1 and 2 years post treatment. The treatment was well tolerated. At 2 years, compared to baseline, a statistically significant improvement was seen in paraprotein concentration, anti-MAG titre, MRC sum score and (from the electrophysiology) the distal motor latency. Percentage of patients improving at 2 years was as follows: Overall neuropathy limitation score 56%, MRC sum score 69%, sensory sum score 61%, anti-MAG titre 100%. These responses compare favourably to those seen with rituximab monotherapy, reported in the literature at 30–50%. On long-term follow-up, 3 cases of glio- blastoma were seen, the aetiology of which is unclear. We suggest there is need for further study of the mechanisms both of the clear neurological benefit but also of the potential risk. ncolchester@yahoo.com