Electrophysiological Testing in Patients with Chronic Inflammatory Demyelinating Polyneuropathy Treated with Subcutaneous Immunoglobulin: The PATH Study (P1.433)

Objective: To determine whether nerve conduction studies (NCS) remain stable in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) during study drug administration with either low or high dose subcutaneous immunoglobulin (SCIG) or placebo. Background: NCS form an essential part of the diagnostic criteria for CIDP and are objective measures of peripheral nerve function independent of confounders that may interfere with clinical scores. Design/Methods: This was a randomized, double-blind trial investigating 0.2 (low) and 0.4 g/kg (high) weekly doses of maintenance SCIG IgPro20 (CSL Behring) versus placebo in 172 subjects. After testing for dependency on Ig therapy, patients were randomized to SCIG or placebo, and NCS were performed at the start and end of the study drug administration period at 25 weeks or early termination. Electrophysiological data from each patient was averaged to give average proximal latency, conduction velocity, conduction block (30, 40 and 50%), compound muscle action potential amplitude, and mean change in averaged parameters of all motor nerves from baseline to completion visit. Results: The majority of NCS parameters did not change; however, averaged proximal latency increased in the placebo group (+1.1 ms) but remained stable in both IgPro20 groups (low dose: +0.1 ms; high dose: −0.1 ms). The averaged motor nerve conduction velocity (MNCV) decreased in the placebo group (−1.6 m/s) but increased in both IgPro20 groups (low dose: +0.2 m/s; high dose: +1.0 m/s). The clinical correlates of these changes will be further explored. Conclusions: Most NCS parameters did not change during the SCIG treatment phase of the PATH study aside from those reflecting speed of conduction (averaged proximal latency and MNCV) which went in a positive direction in SCIG treated patients compared with placebo patients. Study Supported by: CSL Behring Disclosure: Dr. Bril has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Octapharma, Grifols, CSL, UCB. Dr. Van Schaik has received personal compensation in an editorial capacity for Cochrane Neuromuscular Disease Group. Dr. Van Schaik has received research support from CSL Behring; Baxter. Dr. van Geloven has received research support from CSL Behring. Dr. Hartung has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Biogen Idec, GeNeuro, Sanofi Genzyme, Merck, Novartis Pharmaceuticals, Octapharma, Opexa Therapeutics, Teva Pharmaceuticals, MedImmune, Bayer HealthCare, Forward Pharma, and Roche. Dr. Lewis has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with CSL Behring; Axelacare; Pharnext; Biotest; Kedrion; Nufactor; Optioncare; Grifols. Dr. Lewis has received research support from Neutralis; Cytokinetics. Dr. Sobue has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Mitsubishi Tanabe Pharma Co; Shionogi Co Ltd; Bristol Myers Squibb; Sumitomo Dainippon Pharma Co Ltd; Novartis Pharma KK; Bayer Yakuhin Ltd; Pfizer Japan Inc; Boehringer Ingelheim Japan Inc; Kissei Pharmaceutical Co Ltd; Janssen Pharmaceutical KK; Teijin. Dr. Lawo has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with CSL Behring GmbH. Dr. Mielke has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with CSL Behring GmbH. Dr. Durn has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with CSL Behring. Dr. Cornblath has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Acetylon Pharmaceuticals Inc; Alcobra Pharma; Alnylam Pharmaceuticals; Annexon Biosciences; Akros Pharma; Biotest; Boehringer Ingelheim; Cigna Health Management Inc; CSL Behring; DP Clinical Inc; GLAXOSMITHKLINE Plc; Grifols S.A.; Hansa Medical Inc; Karos. Dr. Cornblath has received royalty, license fees, or contractual rights payments from Acetylon Pharmaceuticals Inc; AstraZeneca Pharmaceuticals LP; Calithera Biosciences; Genentech Inc; Neurocrine Biosciences; Merrimack Pharmaceuticals Inc; Seattle Genetics, Inc; Shire Development, LLC. Dr. Merkies has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Talecris. Dr. Merkies has received personal compensation in an editorial capacity for Journal of Peripheral Nervous System.