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Placebo effect in chronic inflammatory demyelinating polyneuropathy: The PATH study and a systematic review
Author(s) -
Lewis Richard A.,
Cornblath David R.,
Hartung HansPeter,
Sobue Gens,
Lawo JohnPhilip,
Mielke Orell,
Durn Billie L.,
Bril Vera,
Merkies Ingemar S. J.,
Bassett Paul,
Cleasby Alexa,
Schaik Ivo N.
Publication year - 2020
Publication title -
journal of the peripheral nervous system
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 67
eISSN - 1529-8027
pISSN - 1085-9489
DOI - 10.1111/jns.12402
Subject(s) - placebo , chronic inflammatory demyelinating polyneuropathy , medicine , clinical endpoint , clinical trial , randomized controlled trial , post hoc analysis , antibody , physical therapy , immunology , pathology , alternative medicine
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.