[Severe hematologic toxicity and its impact on treatment response in newly diagnosed patients with chronic myeloid leukemia receiving tyrosine kinase-inhibitor therapy]

[To compare the efficacy and incidence of severe hematological adverse events of flumatinib and imatinib in patients newly diagnosed with chronic phase chronic myeloid leukemia]

Objective: To analyze and compare therapy responses, outcomes, and incidence of severe hematologic adverse events of flumatinib and imatinib in patients newly diagnosed with chronic phase chronic myeloid leukemia (CML) . Methods: Data of patients with chronic phase CML diagnosed between January 2006 and November 2022 from 76 centers, aged ≥18 years, and received initial flumatinib or imatinib therapy within 6 months after diagnosis in China were retrospectively interrogated. Propensity score matching (PSM) analysis was performed to reduce the bias of the initial TKI selection, and the therapy responses and outcomes of patients receiving initial flumatinib or imatinib therapy were compared. Results: A total of 4 833 adult patients with CML receiving initial imatinib (n=4 380) or flumatinib (n=453) therapy were included in the study. In the imatinib cohort, the median follow-up time was 54 [interquartile range (IQR), 31-85] months, and the 7-year cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) were 95.2%, 88.4%, 78.3%, and 63.0%, respectively. The 7-year FFS, PFS, and OS rates were 71.8%, 93.0%, and 96.9%, respectively. With the median follow-up of 18 (IQR, 13-25) months in the flumatinib cohort, the 2-year cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) were 95.4%, 86.5%, 58.4%, and 46.6%, respectively. The 2-year FFS, PFS, and OS rates were 80.1%, 95.0%, and 99.5%, respectively. The PSM analysis indicated that patients receiving initial flumatinib therapy had significantly higher cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) and higher probabilities of FFS than those receiving the initial imatinib therapy (all P<0.001), whereas the PFS (P=0.230) and OS (P=0.268) were comparable between the two cohorts. The incidence of severe hematologic adverse events (grade≥Ⅲ) was comparable in the two cohorts. Conclusion: Patients receiving initial flumatinib therapy had higher cumulative incidences of therapy responses and higher probability of FFS than those receiving initial imatinib therapy, whereas the incidence of severe hematologic adverse events was comparable between the two cohorts.

Integrative Genomic Analysis Reveals Cancer-Associated Gene Mutations in Chronic Myeloid Leukemia Patients with Resistance or Intolerance to Tyrosine Kinase Inhibitor

Introduction

While the acquisition of mutations in the ABL1 kinase domain (KD) has been identified as a common mechanism behind tyrosine kinase inhibitor (TKI) resistance, recent genetic studies have revealed that patients with TKI resistance or intolerance frequently harbor one or more genetic alterations implicated in myeloid malignancies. This suggests that additional mutations other than ABL1 KD mutations might contribute to disease progression.

Methods

We performed targeted-capture sequencing of 127 known and putative cancer-related genes of 63 patients with CML using next-generation sequencing (NGS), including 42 patients with TKI resistance and 21 with TKI intolerance.

Results

The differences in the number of mutations between groups had no statistical significance. This could be explained in part by not all of the patients having achieved major molecular remission in the early period as expected. Overall, 66 mutations were identified in 96.8% of the patients, most frequently in the KTM2C (31.82%), ABL1 (31.82%), FAT1 (25.76%), and ASXL1 (22.73%) genes. CUX1, KIT, and GATA2 were associated with TKI intolerance, and two of them (CUX1, GATA2) are transcription factors in which mutations were identified in 82.61% of patients with TKI intolerance. ASXL1 mutations were found more frequently in patients with ABL1 KD mutations (38.1% vs 15.21%, P=0.041). Although the number of mutations was low, pairwise interaction between mutated genes showed that ABL1 KD mutations cooccurred with SH2B3 mutations (P<0.05). In Kaplan-Meier analyses, only TET2 mutations were associated with shorter progression-free survival (P=0.026).

Conclusion

Our data suggested that the CUX1, KIT, and GATA2 genes may play important roles in TKI intolerance. ASXL1 and TET2 mutations may be associated with poor patient prognosis. NGS helps improving the clinical risk stratification, which enables the identification of patients with TKI resistance or intolerance in the era of TKI therapy.

[Analysis of the efficacy and influencing factors of nilotinib or dasatinib as second- or third-line treatment in patients with chronic myeloid leukemia in the chronic phase and accelerated phase]

目的

分析二代酪氨酸激酶抑制剂（TKI）尼洛替尼和达沙替尼作为二三线药物治疗慢性髓性白血病（CML）慢性期（CP）和加速期（AP）患者的治疗反应和预后，以及相关影响因素。

方法

回顾性分析2008年1月至2018年11月北京大学人民医院收治的一二线TKI治疗失败并接受尼洛替尼或达沙替尼作为二三线治疗的CML-CP和AP患者资料。

结果

共收集183例尼洛替尼和达沙替尼作为二线治疗和43例尼洛替尼和达沙替尼作为三线治疗的CML-CP或AP患者。二线TKI治疗患者中，中位随访21（1~135）个月，完全血液学反应（CHR）率为80.4%，完全细胞遗传学反应（CCyR）率为56.3%，主要分子学反应（MMR）率为38.3%，3年疾病无进展生存（PFS）和总生存(OS)率分别为78.7%和93.1%。二线TKI治疗中，Sokal积分为高危、女性、一线TKI治疗期间获得最佳反应<CHR、诊断CML距转换二线TKI治疗时间≥18个月、二线TKI治疗前为AP/血液学耐药、二线TKI治疗前未检测出BCR-ABL特殊突变、二线治疗中发生≥3级血液学不良反应是获得细胞遗传学或分子学反应或PFS的不利影响因素。三线TKI治疗患者中，中位随访6（3~129）个月，CHR率为95.7%，CCyR率为29.3%，MMR率为18.6%，2年PFS和OS率分别为66.8%和93.8%。三线TKI治疗中，诊断距一线TKI治疗时间≥6个月、二线TKI治疗期间未获得细胞遗传学反应、诊断距三线TKI治疗时间≥60个月或转换治疗前疾病分期为AP患者获得治疗反应的比例显著降低或预后不良。

结论

尼洛替尼和达沙替尼作为二三线药物可以有效治疗TKI耐药的CML-CP和AP患者，前次TKI治疗期间获得的最佳反应、换药前疾病分期和本次TKI治疗中是否发生≥3级血液学不良反应等因素影响治疗结果。

[Comparison of nilotinib vs imatinib as frontline therapy in newly diagnosed patients with chronic myeloid leukemia in chronic phase]

Objective: To compare the cytogenetic and molecular responses, outcomes and severe hematologic toxicity of nilotinib and imatinib as frontline therapy in newly diagnosed patients with chronic myeloid leukemia in chronic phase (CML-CP) . Methods: Newly diagnosed CML-CP patients were consecutively recruited from January 2006 to December 2018 who received nilotinib and imatinib as first-line treatment. Clinical data were retrospectively analyzed. Results: A total of 524 patients were classified into 439 (83.8%) receiving imatinib and 85 (16.2%) receiving nilotinib. Comparing with imatinib group, patients in nilotinib group were much younger (P=0.019) and more with intermediate and high Sokal risks (P<0.001) , WBC ≥100×10(9)/L (P<0.001) , HGB<120 g/L (P<0.001) , blast cells in bone marrow (P=0.026) , splenomegaly (P<0.001) by physical examination at diagnosis, and longer interval from diagnosis to TKI treatment (P=0.003) . With a median TKI duration of 57 (range 3-153) months, the probabilities of complete cytogenetic response (CCyR) (P=0.011) , major molecular response (MMR) (P=0.001) and MR(4.5) (P=0.046) were much higher in nilotinib group than those in imatnib according to each risk group. There is no statistical significance on probabilities of failure free survival (FFS) , progression free survival (PFS) and overall survival (OS) at 6 years between the two groups. Multivariate analyses showed that imatinib was an adverse factor associated with achieving CCyR (OR=0.6, 95% CI 0.5-0.8, P=0.001) , MMR (OR=0.6, 95% CI 0.5-0.9, P=0.032) and MR(4.5) (OR=0.6, 95%CI 0.5-0.9, P=0.032) and poor FFS (OR=1.9, 95%CI 1.0-3.4, P=0.041) . In addition, Sokal score was an independent factor affecting cytogenetic and molecular responses, treatment failure, disease progression and survival. Male, WBC ≥100×10(9)/L or HGB<120 g/L at diagnosis were significantly associated with lower cytogenetic and molecular response rates and/or poor FFS. The severe hematologic adverse events were not associated with different TKIs. Conclusions: Nilotinib reaches to the faster and deeper cytogenetic and molecular responses and significantly improves FFS than imatinib in newly diagnosed patients with CML-CP.