One key aspect of allogeneic hematopoietic cell transplantation (HCT) is pretransplant conditioning, balancing risk for relapse versus non-relapse mortality. Conditioning regimens with different alkylators at different doses can influence outcome, but data are missing for myelofibrosis, a challenging cohort of patients usually presenting at older age and with comorbidities. We evaluated in a multicenter retrospective study the comparative efficacy and safety of busulfan versus treosulfan in combination with fludarabine for myelofibrosis patients undergoing HCT. This study included 1115 patients (busulfan, n = 902; treosulfan, n = 213) receiving first HCT between 2005 and 2021. Patients were generally balanced for key patient characteristics. Overall survival at 4 years was 62% for the busulfan group versus 58% for the treosulfan group (p = .22). Impact on outcome was dose-dependent. Overall survival was 65% (95% CI, 61%–69%) for reduced intensity busulfan versus 69% (95% CI, 54%–84%) for reduced intensity treosulfan, 53% (95% CI, 44%–63%) for higher intensity busulfan, and 55% (95% CI, 46%–63%) for higher intensity treosulfan. Incidence of relapse was similar across intensity groups. In multivariable analysis, the hazard for death (with reduced intensity busulfan as reference) was 0.88 (95% CI, 0.39–2.01) for reduced intensity treosulfan (p = .77), 1.42 (95% CI, 0.96–2.10) for higher intensity busulfan (0.08), and 1.61 (95% CI, 1.14–2.26) for higher intensity treosulfan (p = .006). In terms of non-relapse mortality, comparison was not significantly different, while the hazard ratio for higher intensity treosulfan was 1.48 (95% CI, 0.98–2.23; p = .06). Here, we showed comparable outcomes and improved survival in myelofibrosis undergoing HCT with reduced intensity busulfan or treosulfan.

中文翻译：

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白消安与三硫丹剂量强度对造血细胞移植骨髓纤维化的影响

同种异体造血细胞移植（HCT）的一个关键方面是移植前调理，平衡复发风险与非复发死亡率。使用不同剂量的不同烷化剂进行调理方案可能会影响结果，但骨髓纤维化的数据缺失，这是一个具有挑战性的患者群体，通常出现在老年并伴有合并症。我们在一项多中心回顾性研究中评估了白消安与三硫丹联合氟达拉滨对接受 HCT 的骨髓纤维化患者的疗效和安全性比较。该研究纳入了 2005 年至 2021 年间接受首次 HCT 的 1115 名患者（白消安，n  = 902；三硫丹，n  = 213）。患者的关键患者特征总体上是平衡的。白消安组 4 年总生存率为 62%，而三硫丹组为 58% ( p  = .22)。对结果的影响是剂量依赖性的。降低强度白消安的总生存率为 65% (95% CI, 61%–69%)，而降低强度三硫丹的总生存率为 69% (95% CI, 54%–84%)，53% (95% CI, 44%–63) %) 对于较高强度白消安，55% (95% CI, 46%–63%) 对于较高强度三硫丹。不同强度组的复发率相似。在多变量分析中，降低强度白消安的死亡风险（以降低强度白消安为参考）为 0.88 (95% CI, 0.39–2.01)，降低强度三硫丹 ( p  = .77)，较高剂量为 1.42 (95% CI, 0.96–2.10)。强度白消安 (0.08)，更高强度三硫丹为 1.61 (95% CI，1.14–2.26) ( p  = .006)。就非复发死亡率而言，比较没有显着差异，而较高强度三硫丹的风险比为 1.48（95% CI，0.98–2.23；p  = .06）。在这里，我们在接受强度降低的白消安或三消安 HCT 的骨髓纤维化中显示出可比的结果并提高了生存率。