Placebo effect in chronic inflammatory demyelinating polyneuropathy: The PATH study and a systematic review.

Abstract

The Polyneuropathy And Treatment with Hizentra (PATH) study required subjects with chronic inflammatory demyelinating polyneuropathy (CIDP) to show dependency on immunoglobulin G (IgG) and then be restabilized on IgG before being randomized to placebo or one of two doses of subcutaneous immunoglobulin (SCIG). Nineteen of the 51 subjects (37%) randomized to placebo did not relapse over the next 24 weeks. This article explores the reasons for this effect. A post-hoc analysis of the PATH placebo group was undertaken. A literature search identified other placebo-controlled CIDP trials for review and comparison. In PATH, subjects randomized to placebo who did not relapse were significantly older, had more severe disease, and took longer to deteriorate in the IgG dependency period compared with those who relapsed. Published trials in CIDP, whose primary endpoint was stability or deterioration, had a mean non-deterioration (placebo effect) of 43%, while trials with a primary endpoint of improvement had a placebo response of only 11%. Placebo is an important variable in the design of CIDP trials. Trials designed to show clinical improvement will have a significantly lower effect of this phenomenon than those designed to show stability or deterioration.

• Authors: Richard A Lewis, David R Cornblath, Hans-Peter Hartung, Gens Sobue, John-Philip Lawo, Orell Mielke, Billie L Durn, Vera Bril, Ingemar S J Merkies, Paul Bassett, Alexa Cleasby, Ivo N van Schaik, PATH study group
• Journal: Journal of the peripheral nervous system : JPNS (J Peripher Nerv Syst) Vol. 25 Issue 3 Pg. 230-237 (09 2020) ISSN: 1529-8027 [Electronic] United States
• PMID: 32627277 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Systematic Review)
• Copyright: © 2020 CSL Behring. Journal of the Peripheral Nervous System published by Wiley Periodicals LLC on behalf of Peripheral Nerve Society.

Chemical References

• Immunologic Factors

Topics

• Humans
• Immunologic Factors
• Outcome Assessment, Health Care
• Placebo Effect
• Polyradiculoneuropathy, Chronic Inflammatory Demyelinating (drug therapy)
• Randomized Controlled Trials as Topic
• Research Design