Objectives Rituximab use early in the course of refractory idiopathic inflammatory myopathy(IIM) is not well studied. This study sought to determine the short-term efficacy of RTX in a registry based cohort of refractory IIM. Methods Registry based observational data about IIM patients receiving rituximab(RTX) between 2018–2021 were included. Total improvement score(TIS) was calculated from the core set measures as per IMACS at baseline, 6 months and 12 months of follow-up. Results Forty two patients (F: M::29:13), with a mean(SD) age of 39.5(±11.5) years were studied. Majority of patients received rituximab for refractory myositis, after a median(IQR) duration of 8(4,18) months. Twenty-eight received RTX at a dosage of 1 gram *2 doses, while 14 received 500 mg * 2 doses with an interval of 15 days. At 6 months and 12 months post RTX, the improvement was recorded in manual muscle testing(MMT-8) scores, PGA(physician global assessment), PtGA(patient global assessment), median steroid dosage as compared with the baseline (p< 0.01 for all). A mean(SD) improvement of 44.5 ± 16 and 48.7 ± 19.2 in TIS was recorded at 6 months and 12 months respectively. The change in MMT-8, PGA and PtGA scores from baseline between the two dosage regimens of RTX were comparable at 6 months and 12 months. Severe lower respiratory tract infections requiring hospitalisation occurred in 3 patients of the cohort. Conclusion Rituximab improved IMACS core set measures and had steroid sparing efficacy at 6 and 12 months in patients with IIM in this registry-based study. Rituximab as an induction regimen of 2 doses of 500 mg can be as efficacious as 1 g at 6 months and 12 months of follow-up.

中文翻译：

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低剂量利妥昔单抗对难治性特发性炎症性肌病有效

目的 利妥昔单抗在难治性特发性炎症性肌病 (IIM) 病程早期的使用尚未得到充分研究。本研究旨在确定 RTX 在基于注册的难治性 IIM 队列中的短期疗效。方法 纳入了 2018-2021 年间接受利妥昔单抗 (RTX) 治疗的 IIM 患者的基于注册表的观察数据。在基线、6 个月和 12 个月的随访中，根据 IMACS 根据核心集测量计算总改善评分 (TIS)。结果 研究了 42 名患者 (F: M::29:13)，平均 (SD) 年龄为 39.5 (±11.5) 岁。大多数患者在中位 (IQR) 持续 8(4,18) 个月后接受利妥昔单抗治疗难治性肌炎。28 人接受了 1 克 * 2 剂剂量的 RTX，而 14 人接受了 500 毫克 * 2 剂，间隔为 15 天。在 RTX 后 6 个月和 12 个月时，改进记录在手动肌肉测试 (MMT-8) 分数、PGA（医生整体评估）、PtGA（患者整体评估）、与基线相比的类固醇剂量中位数（所有 p < 0.01）。在 6 个月和 12 个月时，TIS 的平均 (SD) 改善分别为 44.5 ± 16 和 48.7 ± 19.2。在 6 个月和 12 个月时，两种 RTX 给药方案之间 MMT-8、PGA 和 PtGA 评分相对于基线的变化具有可比性。该队列中有 3 名患者出现需要住院治疗的严重下呼吸道感染。结论 在这项基于注册的研究中，利妥昔单抗改善了 IMACS 核心组指标，并在 6 个月和 12 个月时对 IIM 患者具有类固醇节约疗效。利妥昔单抗作为 2 剂 500 mg 的诱导方案，在 6 个月和 12 个月的随访中与 1 g 一样有效。