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.

中文翻译：

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慢性炎症性脱髓鞘性多发性神经病的安慰剂效应：PATH 研究和系统评价。

多发性神经病和 Hizentra 治疗 (PATH) 研究要求患有慢性炎症性脱髓鞘性多发性神经病 (CIDP) 的受试者表现出对免疫球蛋白 G (IgG) 的依赖性，然后在随机分配至安慰剂或两种皮下免疫球蛋白 (SCIG) 剂量之一之前，先用 IgG 重新稳定）。随机分配到安慰剂组的 51 名受试者中有 19 名 (37%) 在接下来的 24 周内没有复发。本文探讨了这种影响的原因。对 PATH 安慰剂组进行了事后分析。一项文献检索确定了其他安慰剂对照 CIDP 试验以供审查和比较。在 PATH 中，随机分配到安慰剂组的受试者与复发的受试者相比，年龄显着更大，病情更严重，并且在 IgG 依赖期恶化所需的时间更长。在 CIDP 中发表的试验，其主要终点是稳定性或恶化，平均未恶化（安慰剂效应）为 43%，而主要终点改善的试验的安慰剂反应仅为 11%。安慰剂是 CIDP 试验设计中的一个重要变量。与旨在显示稳定性或恶化的试验相比，旨在显示临床改善的试验对这种现象的影响将显着降低。