Hasford Score Is Correlated with 18 Month Molecular Response for Chronic Myeloid Leukemia Patients Treated with Second Generation Tyrosine Kinase Inhibitors and It May be Useful to Differentiate Low and Intermediate Risk Patients: A Single Institution Experience
Authors: Dybko Jaroslaw , Haus Olga , Jazwiec Bozena , Lonc Tomasz , Sawicki Mateusz , Kuliczkowski Kazimierz 
Published: October 2019

Abstract
BACKGROUND: Chronic myeloid leukemia (CML) has been a model disease for a variety of studies concerning scoring systems, graft versus leukemia effect or tyrosine kinase inhibitors (TKI) treatment for many years. Scoring systems playing an important role in modern medicine to establish risk-adjusted optimal therapy [1] have been always essential for CML changing treatment modalities [1-3]. The three principal risk scores : Sokal [2], Hasford [1] and European Treatment and Outcome Study (EUTOS) [3] were established in different eras of CML therapy with implications for prognosis and disease outcome [4]. Hasford metric was designed based on data of patients treated with interpheron alpha [1] and it failed to differentiate patients who achieved low and intermediate risk scores according to CCyR, MMR, and 5 years EFS [5]. However in our previous study we found Hasford score to be correlated with the long-term molecular response in patients treated with imatinib [6]. This study presents the analysis of patients treated with second generation tyrosine kinase inhibitors (2G-TKI) due to their loss of MMR on imatinib. Hasford score still distinguish patients with low and intermediate risk and correlates with 18 month molecular response. PATIENTS AND RESULTS: The original group of 88 CML patients (F/M:42/46, median age 51 (21-83), 57 low risk and 31 intermediate risk assessed by Hasford risk score) in first chronic phase without any additional chromosomal abnormalities receiving standard dose imatinib was described in our previous study [6]. Of these, 42 patients lost MMR in a median time of 47 months. Within this group we identified 20 low risk (LR) and 22 intermediate risk (IR) patients. All 42 patients were switched to 2G-TKI. The observation after 3 months of 2G-TKI treatment was also previously described. After 18 months of 2G-TKI treatment median bcr-abl transcript levels in the LR group were 0.002 (0.000-0.02) but in the IR group bcr-abl levels were 0.03 (0.000-21.1) (p=0.03, Figure 1). All 20 low risk patients achieved major molecular response (MMR). In the intermediate risk group the response rate (MMR) was approximately 73% (16/22) and there is a significant difference in a probability of achieving MMR in both groups (Fig.2, p=0.0002). CONCLUSIONS: We are aware of Hasford score limited usefulness in predicting MMR in large studies. However in our study it is still a tool to distinguish low and intermediate risk patients by their molecular response on 2G-TKI after imatinib failure. We find our results relevant to the discussion on optimizing scoring systems and first line treatment of CML patients.
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Figure 1. Figure 1. Figure 2. Figure 2.

Disclosures
No relevant conflicts of interest to declare.