Background

More than one-third of patients with acute myeloid leukemia (AML) will relapse after allogenic hematopoietic cell transplant (allo-HCT). The main challenge is to overcome disease resistance to achieve a new complete remission while avoiding excessive toxicity. Gemtuzumab ozogamicin (GO), a conjugate of calicheamicin linked to the humanized monoclonal anti-CD33 antibody, has been used for refractory or relapsed AML with promising response rates, but liver toxicity of GO has long been considered a limiting factor.

Patients and Methods

We included 18 consecutive patients with AML relapsing after a first allo-HCT and treated with fractioned GO (fGO) and intensive chemotherapy. The median age was 40 years (range, 18-65).

Results

The overall response rate was 72% (13/18), including 7 complete remissions. No death was attributed to treatment toxicity. The main liver toxicity was transient and consisted of transaminase level elevation and hyperbilirubinemia. No cases of veno-occlusive disease were observed after the GO treatment. From the time of salvage treatment initiation, 1- and 2-year OS rates were 54% (95% confidence interval, 28%-74%) and 42% (95% confidence interval, 19%-63%), respectively.

Conclusions

Our study suggests the feasibility, efficacy, and safety of an fGO-based salvage regimen combined with intensive chemotherapy in patients with CD33+ AML in the case of early relapse after an allo-HCT.

中文翻译：

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Gemtuzumab Ozogamicin联合强化化疗治疗同种异体干细胞移植后急性髓系白血病复发患者。

背景

超过三分之一的急性髓系白血病 (AML) 患者在同种异体造血细胞移植 (allo-HCT) 后会复发。主要挑战是克服疾病抵抗力以实现新的完全缓解，同时避免过度毒性。Gemtuzumab ozogamicin (GO) 是一种与人源化单克隆抗 CD33 抗体相连的加利车霉素偶联物，已用于治疗难治性或复发性 AML，并具有良好的反应率，但长期以来，GO 的肝毒性一直被认为是一个限制因素。

患者和方法

我们纳入了 18 名在第一次 allo-HCT 后复发并接受分段 GO (fGO) 和强化化疗的连续 AML 患者。中位年龄为 40 岁（范围，18-65 岁）。

结果

总缓解率为 72% (13/18)，包括 7 次完全缓解。没有死亡归因于治疗毒性。主要的肝毒性是短暂的，包括转氨酶水平升高和高胆红素血症。GO治疗后未观察到静脉闭塞性疾病病例。从挽救治疗开始，1 年和 2 年 OS 率分别为 54%（95% 置信区间，28%-74%）和 42%（95% 置信区间，19%-63%）。

结论

我们的研究表明，在同种异体 HCT 后早期复发的情况下，基于 fGO 的补救方案联合强化化疗在 CD33+ AML 患者中的可行性、有效性和安全性。