Intravenous methylprednisolone as add-on induction therapy for chronic inflammatory demyelinating polyradiculoneuropathy: a randomised controlled trial

Background: Most patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) require maintenance treatment. We aimed to determine whether combined treatment with intravenous immunoglobulin (IVIg) and intravenous methylprednisolone (IVMP) increases remission rates compared with IVIg and placebo. Methods: We performed a randomised, double-blind, placebo-controlled study. Adults with CIDP who were treatment naive, relapsed after a remission or required continued treatment after a single IVIg dose were included. Participants were treated with IVMP (1000 mg) or placebo (sodium chloride) every 3 weeks for 18 weeks. All participants received IVIg treatment consisting of a loading dose (2 g/kg) and serial maintenance treatments (1 g/kg). The primary outcome was remission, defined as sustained improvement on disability scales at 52 weeks without need for further treatment. Results: Enrolment was halted after the inclusion of 77 of the 96 planned participants because of safety concerns: four thromboembolic events occurred in the IVIg/IVMP group compared with none in the IVIg/placebo group. 14 of 37 (38%) participants in the IVIg/IVMP group were in remission at 52 weeks compared with 11 out of 40 (28%) in the IVIg/placebo group, with a difference of 10% (95% CI −11 to 31; p=0.47). Several secondary outcomes showed a greater magnitude of improvement in disability and impairment at 18 and 52 weeks in the IVIg/IVMP group. Conclusions: The study was prematurely stopped due to safety concerns after four thromboembolic events in the IVIg plus IVMP group. Combined treatment did not lead to significantly more frequent remissions than IVIg alone in the doses used in this study. Trial registration number: ISRCTN15893334.