DP050 | ASSESSING THE IMPACT OF COMORBIDITIES IN HAIRY CELL LEUKEMIA: VALIDATION OF THE CLL-CI/TRES SCORE IN PATIENTS TREATED WITH PURINE ANALOGUES

Introduction Hairy cell leukemia (HCL) is an indolent disease that enjoys excellent response and durable remissions after therapy with the purine analogues (PAs) cladribine (2CDA) and pentostatin (DCF). Yet, the impact of different comorbidities on HCL outcomes is still unknown, and no standardized method for the evaluation of comorbidities exists in HCL. Aim The CLL-CI/TRES score is an easy-to-use clinical tool that was initially developed to evaluate comorbidities in CLL and then validated in patients with non-Hodgkin lymphomas, but never in HCL. In this study, we aimed to validate this score in a cohort of patients with HCL treated with PAs. Methods We extracted relevant clinical information from the medical records of 98 patients with HCL treated with PAs from 1992 until 2024. The TRES score was calculated as previously reported by assigning 1 point to each involved system: vascular, upper GI and endocrine. Patients were then classified as follows based on the total score: 0 low-, 1 intermediate- and 2-3 high-risk. Results The median age was 59 years (range 33-82), 18 (18%) patients were female. Sixty-nine (70%) were treated with 2CDA and 29 (30%) with DCF, 83 (85%) for newly diagnosed (ND) and 15 (15%) for relapsed (R/R) disease. Forty-seven (48%) patients were classified as TRES low-risk, 38 (39%) as intermediate and 13 (13%) as high-risk. Vascular comorbidities were the most common (n=44, 45%), followed by endocrine (n=12, 12%) and upper GI (n=9, 9%). The 10-year PFS was 75%, 35% and 55% for the low, intermediate and high-risk categories respectively (figure), and the 10-year OS 100%, 71% and 90%. A significant difference in PFS and OS was observed between low and intermediate-risk patients (both p <0.0001), but not between intermediate and high ones (p=0.3 and 0.5). In a multivariate analysis adjusting for age, sex, type of therapy and disease status (ND vs. R/R), intermediate-risk TRES was independently associated with worse PFS (HR 4.22; p=0.002). Conclusion The TRES score was associated with both PFS and OS reflecting the impact of comorbidities on HCL outcomes. The inability to demonstrate different outcomes between intermediate and high-risk patients was likely due to the low number of patients and events in the latter group. Overall, the TRES score could be a viable tool to assess comorbidities and aid in selecting/developing more tolerable therapeutic strategies for higher risk patients, thus deserving further validation in a larger cohort.