Patients with Philadelphia-positive leukemia with Y253H or F359V mutation have a high risk of developing new mutations in the setting of dasatinib resistance

[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。

[Dasatinib treatment based on BCR- ABL mutation detection in imatinib- resistant patients with chronic myeloid leukemia]

OBJECTIVE

To evaluate the efficiency of dasatinib as the second- or third-line tyrosine kinase inhibitor (TKI)in imatinib-resistant patients with chronic myeloid leukemia (CML)based on BCR-ABL mutation detection.

METHODS

122 CML patients received dasatinib treatment, including 83 with imatinib-resistance and 39 with both imatinib- and nilotinib-resistance, 55 in the chronic-phase (CP), 21 in the accelerated- phase (AP)and 46 in the blast- phase (BP). Those harboring dasatinib highly- resistant mutations (T315I/A, F317L/V/C and V299L)were excluded based on BCR-ABL kinase domain mutation screening by Sanger sequencing at baseline. Hematologic, cytogenetic and molecular responses were evaluated regularly, and rates of progression-free-survival (PFS)and overall survival (OS)were analyzed. BCR- ABL mutation detection was performed once the patients failed on dasatinib.

RESULTS

In the CP patients, the rates of complete hematological response (CHR), complete cytogenetic response (CCyR), major molecular response (MMR)and molecular response 4.5 (MR4.5)were 92.7%, 53.7%, 29.6% and 14.8%, respectively. 4-year PFS and OS rates were 84.4% and 89.5%, respectively. In the AP patients, HR and CCyR rates were 81.0% and 35.0%; and 3-year PFS and OS rates were 56.1% and 59.3%, respectively. In the BP patients, HR and CCyR rates were 63.0% and 21.4%; and 1-year PFS and OS rates were 43.6% and 61.8%, respectively. Outcomes were similar when dasatinib was used as the second- line TKI or the third-line TKI. Of the 75 patients who were resistant to dasatinib, 37 (48.7%)developed new mutation(s), and T315I (59.5%)was the most common mutation type. The patients who already harbored mutation(s)before dasatinib therapy achieved similar responses and outcomes to those with no mutation at baseline. However, they had higher likelihood of developing additional mutations associated with resistance to dasatinib (65.7%vs 34.1%,P=0.006).

CONCLUSIONS

Dasatinib was proved to be effective in the treatment of imatinib- or/and nilotinib-resistant CML patients, especially in both CP and AP cohorts. The significance of BCR-ABL mutation screening and monitoring should be highlighted before and during dasatinib therapy.