Low-dose post-transplant cyclophosphamide (PTCy) in conjunction with anti-thymocyte globulin (ATG) appears as a potentially effective graft-versus-host disease (GVHD) prevention strategy in haploidentical hematopoietic cell transplant (haplo-HCT). Our study aims to assess the efficacy of this regimen. We extended our prospective study in patients treated with low-dose PTCy (14.5 mg/kg on days 3 and 4) in ATG/granulocyte colony-stimulating factor (G-CSF)-based regimen and compared the results to the contemporary cohort of patients without low-dose PTCy (ATG cohort). Both study cohort and control are transplanted from maternal donor or collateral relatives. We identified 239 consecutive patients (ATG-PTCy cohort = 114; ATG cohort = 125). All patients but one in ATG cohort achieved myeloid engraftment by day 30 post-HCT. We found that both the cumulative incidence of 100-day grade III–IV aGvHD and non-relapse-mortality (NRM) in the ATG-PTCy cohort was significantly reduced than that in the ATG group (5% vs 18%; P = 0.003; and 6% vs 15%; P= 0.045); the 2-year cumulative incidences of relapse and overall survival were comparable between the two cohorts (13% vs 14%; P = 0.62; and 83% vs 77%; P = 0.18, respectively). Furthermore, GVHD-free, relapse-free survival (GRFS) was significantly improved in the ATG-PTCy arm (63% vs 48%; P = 0.039). In multivariate analysis, the joint treatment resulted in lower grade II–IV acute GVHD (HR 0.58; P = 0.036), grade III–IV aGvHD (HR 0.28; P = 0.006), chronic GVHD (HR 0.60; P = 0.047), NRM (HR 0.26; P = 0.014), and higher GRFS (HR 0.59; P = 0.021) but slower myeloid and platelet recovery (HR 0.29 and 0.30; both P < 0.001). These results suggested that ATG/PTCy (low-dose) can reduce both acute and chronic GVHD as compared with standard ATG-based prophylaxis using maternal donor or collateral relatives at particular high GVHD risk.

中文翻译：

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移植后低剂量环磷酰胺和抗胸腺细胞球蛋白是单倍体相合患者预防​​ GVHD 的有效策略。

低剂量移植后环磷酰胺 (PTCy) 联合抗胸腺细胞球蛋白 (ATG) 似乎是半相合造血细胞移植 (haplo-HCT) 中潜在有效的移植物抗宿主病 (GVHD) 预防策略。我们的研究旨在评估该方案的疗效。我们在基于 ATG/粒细胞集落刺激因子 (G-CSF) 的方案中对接受低剂量 PTCy（第 3 天和第 4 天 14.5 mg/kg）治疗的患者扩展了前瞻性研究，并将结果与​​当代患者队列进行了比较没有低剂量 PTCy（ATG 队列）。研究队列和对照都是从母体捐赠者或旁系亲属移植的。我们确定了 239 名连续患者（ATG-PTCy 队列 = 114；ATG 队列 = 125）。除 ATG 队列中的一名患者外，所有患者在 HCT 后第 30 天均实现了骨髓移植。我们发现，ATG-PTCy 队列中 100 天 III-IV 级 aGvHD 的累积发生率和非复发死亡率 (NRM) 均显着低于 ATG 组（5% vs 18%；P = 0.003） ；以及 6% 与 15%；P= 0.045)；两个队列的 2 年累积复发率和总生存率相当（分别为 13% vs 14%；P = 0.62；83% vs 77%；P = 0.18）。此外，ATG-PTCy 组的无 GVHD、无复发生存率 (GRFS) 显着改善（63% vs 48%；P = 0.039）。在多变量分析中，联合治疗导致较低的 II-IV 级急性 GVHD（HR 0.58；P = 0.036）、III-IV 级 aGvHD（HR 0.28；P = 0.006）、慢性 GVHD（HR 0.60；P = 0.047）、 NRM（HR 0.26；P = 0.014）和较高的 GRFS（HR 0.59；P = 0.021），但骨髓和血小板恢复较慢（HR 0.29 和 0.30；均 P < 0.001）。这些结果表明，与使用具有特别高 GVHD 风险的母体供体或旁系亲属的标准 ATG 预防相比，ATG/PTCy（低剂量）可以减少急性和慢性 GVHD。