At least partial hematological response after first cycle of treatment predicts organ response and long-term survival for patients with AL amyloidosis receiving bortezomib-based treatment

AL amyloidosis is a rare plasma cell dyscrasia characterized by multi-organ involvement and poor prognosis. We retrospectively evaluated the organ response (OR) and long-term survival of newly diagnosed AL amyloidosis patients who received first-line bortezomib-containing induction therapy, aiming to identify the clinical indication of a 50% reduction in the difference between involved and uninvolved free light chains (dFLC) after first cycle of treatment. Among the 89 patients included, 78.7% had cardiac involvement and 42.7% were diagnosed with 2004 Mayo stage III disease, while 75.3% of patients achieved a hematological response, including 37.1% with complete response and a median response time of 1 month. Cardiac and renal responses were observed in 44.3 and 53.1% of patients, respectively. Sixty-one (68.5%) patients achieved at least 50% reduction in dFLC after the first cycle of therapy. After a median follow-up duration of 12 months, the estimated 3-year progression-free survival (PFS) and overall survival (OS) rates were 61.3 and 61.7% respectively. At least 50% reduction in dFLC after the first cycle of therapy was predictive of achieving an OR ( p = 0.002), as well as superior PFS (HR = 0.119; 95% CI = 0.045–0.313; p