LAUSR

Patients with immunoglobulin light chain (AL) amyloidosis and stage IIIb cardiac involvement have a dismal outcome despite the introduction of novel treatments. However, a rapid hematologic response translates in better survival. We evaluated the impact of early cardiac response and its depth on outcome in 249 patients with newly-diagnosed stage IIIb cardiac AL amyloidosis. Hematologic and cardiac responses were evaluated by intent to treat. After a median follow-up of 52 months, 219 (84%) patients died, and median survival was 4.2 months. The 30- and 90-day hematologic response rates were 22% (at least very good partial response [VGPR] in 9%) and 24% (at last VGPR in 15%), respectively. Early hematologic response resulted in better survival. At 90 days, 21 (8%) patients achieved a cardiac response (cardiac very good partial response [cardiac VGPR] in 12 cases and cardiac partial response [cardiac PR] in 9). At 90-day landmark analysis, cardiac response resulted in longer survival (median 54 months), also in patients with at least VGPR (median 62 vs. 26 months, P=0.011). Patients with cardiac VGPR had a longer survival than those with cardiac PR (median 92 vs. 24 months; P=0.027), while patients without cardiac response had a poor survival (median 6 months). A baseline difference of involved/uninvolved free light chains (dFLC) >50 mg/L (OR 0.21, P=0.024) and a bone marrow plasma cell infiltrate >10% (OR 0.23, P=0.040) were negative predictors of 90-day cardiac response. Early cardiac responses are rare but possible in stage IIIb AL amyloidosis and translate in longer survival.