P132 | IS ANTI-THYMOCYTE GLOBULIN STILL A VIABLE TREATMENT OPTION FOR OLDER PATIENTS WITH APLASTIC ANEMIA? A SINGLE-CENTER EXPERIENCE

Patients over 60 years old affected by acquired aplastic anemia (AAA) face challenges related to comorbidities and reduced tolerance to intensive treatments. Standard therapy includes immunosuppressive treatment (IST) with anti-thymocyte globulin plus cyclosporine (ATG+CSA), with or without eltrombopag (ELT), or hematopoietic stem cell transplantation (HSCT) in selected cases. We retrospectively analyzed 20 patients >60 years diagnosed with AAA (Camitta criteria) and treated at our center between January 2014 and December 2024. This study evaluates the feasibility and safety of ATG+CSA in elderly AAA pts. Horse-ATG was administered at 40 mg/kg/day x4 days and CSA at 5 mg/kg. ELT (up to 150 mg/day) was introduced after 3 months in non-responders. Responses were assessed by EBMT criteria: complete response (CR, hemoglobin >10 g/dL, ANC >1.5×10⁹/L, platelets >100×10⁹/L); partial response (PR, transfusion independence); no response (NR, persistent transfusion dependence). Median age was 71y (range 60–82). Two patients (10%) had non-severe, transfusion-dependent AA; 9 (45%) had severe AA; and 9 (45%) had very severe AA. Eight patients (40%) had a small PNH clone. In patients >70 (30% of the cohort), ATG dose was reduced by 50%. At three months, the overall response rate (ORR, CR + PR) was 30% (6/20). Five patients (median age 76y; range 69-77) died due to complications (aspergillus pneumonia 2, cardiac arrest, cerebral hemorrhage, septic shock). Of 9 non-responders, 7 received ELT. After an additional four months, the ORR increased to 60% (12/20), with all initial responders maintaining their response and 6/7 ELT-treated patients responded (3 CRs, 9 PRs in total). Major complications within the first three months among survivors included fever of unknown origin (5/14, 35%), cardiac events (3/14, 21%)—two cases of atrial fibrillation and one of heart failure post-ATG—and one instance of grade 3 hepatic toxicity post-ELT (1/14, 7%). At 39 months median follow-up (range 0-154), the median survival has not been reached (Fig. 1). Despite hematologic responses, ATG treatment was associated with notable early mortality (25%) and morbidity in the elderly. The addition of eltrombopag improved response rates with manageable toxicity. Further studies are warranted to evaluate whether a combination of CSA and eltrombopag, excluding ATG, could represent a safer and effective first-line strategy in elderly AAA patients.