P181 | MULTIPLE MYELOMA SYMPTOMATIC ONLY FOR AL AMYLOIDOSIS: A MONOCENTRIC CLINICAL EXPERIENCE

Background. Multiple Myeloma with light-chain amyloidosis (AL-MM) is associated with worse prognosis and higher mortality rates: however, there is currently a gap in information on the management of such patients. We report a retrospective monocentric experience including patients diagnosed with Multiple Myeloma with amyloidosis as the organ damage. Methods. We collected patients with newly diagnosed AL-MM between January 2023 and March 2025. AL-amyloidosis was diagnosed by organ biopsy or cardiovascular MRI: patients meeting CRAB criteria were excluded. Results. Between January 2023 and March 2025, we collected 17 MM-AL patients without CRAB criteria: baseline characteristics are reported in Table 1. The median age at diagnosis was 62 years (range 47-72). The organ most involved was the heart (64.7%). FISH was evaluable in 7 patients with evidence of t(11;14) in 5 cases (29.4%). An ECOG ≥2 was found in 47% of patients at the diagnosis. As for treatment, all of patients received first-line induction therapy including Daratumumab and Bortezomib and obtained at least a partial haematological response. Dosage modifications or temporary interruptions of the treatment were required in half of the patients due to infections (29.4%), haemorrages (5.9%), thrombosis (11.7%) and toxicity (41.1%). Fourteen patients were eligible for autologous stem cell transplant (ASCT) due to age < 70 years (82.3%): 3 patients died during induction therapy, 2 was excluded for comorbidities and 4 patients are still undergoing induction therapy, therefore 5 patients completed the transplant program. Mobilization of peripheral blood cells was induced with Cyclophosphamide (CTX), granulocyte colony stimulating factor (G-CSF) and Plerixafor in 1 patient, while in 4 patients we used only G-CSF and Plerixafor: we observed no stem cells yield failures, with a median collection of 4.55 x 10^6/Kg (range 2.68-25). After a median follow up of 7 months, 76.5% of patients were alive: the four deaths all occurred within the first 3 months following diagnosis and the cause of death was amyloidosis in 75% of patients (1 patients died for infection). Conclusions. The early mortality rate related to amyloidosis was 23.5%: however, patients who have survived the first three months of treatment have shown a response rate of and have tolerated the treatment. All transplant-eligible patients who completed the induction treatment underwent ASCT except for two who were excluded for comorbidities.