P091 | LUSPATERCEPT IN LOW-RISK MYELODYSPLASTIC SYNDROME WITH RING SIDEROBLASTS: A LONG-TERM REAL-LIFE EXPERIENCE

Luspatercept (Luspa) is a first-in-class erythroid maturation agent approved for transfusion dependent anemia refractory or ineligible to ESAs in patients with low risk MDS-RS. Despite evidence of Luspa efficacy in both clinical trials and real-world studies, long-term follow-up data are still scarce. Moreover, in MEDALIST Trial, Luspa seems to induce haematological improvement also on granulocytic and platelets lines. Thus, we analysed in a real-life setting Luspa long-term efficacy on erythroid response, as well as Luspa’s impact on others cell lines. We retrospectively collected data of 44 patients treated with Luspa from January 2021 to date. Patients were diagnosed with MDS with low blast count and SF3B1 mutation and/or ring sideroblasts (WHO 2022). Both Revised International Prognostic Score (IPSS-R) and the Molecular International Prognostic Score (IPSS-M) were calculated at diagnosis. All patients had ESA-refractory transfusion anaemia. Treatment response was evaluated at 24 weeks, 1 year and 2 year after the start of Luspatercept using haematological response criteria proposed by the IWG 2018. At baseline, 18 (41%) and 26 (59%) patients had Low transfusion burden and High transfusion burden, respectively. Among the 36 patients evaluable at 24 weeks, 19 (53%) patients reached a response and 17 (47%) patients were not responsers (NR). At 1 year, 13 (46%) patients showed a response, including 12 patients who had already responded at 24 weeks, while 1 patient showed a de novo response. At long-term evaluation at 2 years, out of 14 evaluable patients, 8 (57%) maintained the response and 1 (7%) patient were a de novo responder. All NR patients reached the maximum Luspa dose and continued the treatment in presence of a reduction of transfusion burden, although they did not meet 2018 IWG HI criteria. In our cohort, no patients had remarkable side effects, 18 patients discontinued the treatment due to lack of response or patient’s choice and 18 patients are still in treatment. Platelets count at 24 weeks, 1 year and 2 years did not change compared to baseline levels; while neutrophil count at 1 year is significantly increased (p=0.03) compared to pre-Luspa levels. In our real-life experience, Luspa demonstrates to be able to maintain erythroid response in long-term follow-up. The potential capability of Luspa to induce haematological improvement on granulocytic cell line needs further investigations.