Pediatric chronic myeloid leukemia (pCML) is a rare childhood malignancy, representing 2%–3% of all childhood leukemia. Tyrosine kinase inhibitors (TKIs) have greatly improved survival but pose challenges due to their long‐term effects on growth and bone health in children. We prospectively studied treatment‐free remission (TFR) in 45 children with pCML in chronic phase on imatinib. Eligibility criteria were as per current NCCN guidelines, with a less stringent qPCR monitoring scheduled every 3 months. TFR was successful in 71.1% (32 out of 45) of patients after a median follow‐up of 25 (range: 6–42) months. The TFR rates at 12 and 24 months were 70% and 66%, respectively. Children under 5 years had a TFR rate of 88.9%, compared to 61.8% in those over 5 years (p = 0.18). Eleven of the 13 patients who lost MMR did so within 6 months of discontinuation. The cumulative incidence of loss in MMR at 6, 12, and 24 months was 26.4%, 27%, and 33%, respectively. Ten out of 13 (76.9%) patients with discontinuation failure (DF) regained MMR within 3 (2–20) months of restarting imatinib. A significant correlation was found between higher T‐regulatory cell levels at baseline and DF (p = 0.005). More than half patients showed improved bone mineral density after 2 years of TFR. Our findings suggest that high TFR rates can be attained in pCML, with added benefits for bone health. Less frequent molecular monitoring was not associated with adverse outcomes and there seems to be a role of the immune system in sustaining TFR. The study is registered in the Clinical Trials Registry‐India (CTRI/2020/11/029199).

中文翻译：

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慢性粒细胞白血病 （CML） 儿童的无治疗缓解：来自塔塔纪念医院 （TMH） 儿科 CML （pCML） 队列的前瞻性研究


小儿慢性粒细胞白血病 （pCML） 是一种罕见的儿童恶性肿瘤，占所有儿童白血病的 2%-3%。酪氨酸激酶抑制剂 （TKI） 大大提高了生存率，但由于其对儿童生长和骨骼健康的长期影响，因此带来了挑战。我们前瞻性研究了 45 例服用伊马替尼的慢性期 pCML 儿童的无治疗缓解 （TFR）。资格标准符合当前的 NCCN 指南，每 3 个月安排一次不太严格的 qPCR 监测。中位随访 25 个月 （范围： 6-42） 个月后，71.1% （45 例中的 32 例） 患者的 TFR 成功。12 个月和 24 个月的 TFR 率分别为 70% 和 66%。5 岁以下儿童的 TFR 率为 88.9%，而 5 岁以上儿童的 TFR 率为 61.8% （p = 0.18）。13 例丢失 MMR 的患者中有 11 例是在停药后 6 个月内丢失的。6 、 12 和 24 个月时 MMR 的累积丢失发生率分别为 26.4% 、 27% 和 33%。13 名停药失败 （DF） 患者中有 10 名 （76.9%） 在重新启动伊马替尼后 3 （2-20） 个月内恢复了 MMR。发现基线时较高的 T 调节细胞水平与 DF 之间存在显著相关性 （p = 0.005）。超过一半的患者在 TFR 2 年后表现出骨密度改善。我们的研究结果表明，pCML 可以获得高 TFR 率，对骨骼健康有更多好处。不太频繁的分子监测与不良结局无关，并且免疫系统似乎在维持 TFR 方面发挥作用。该研究已在印度临床试验注册库 （CTRI/2020/11/029199） 注册。