Background: Organ response (OR) in AL is often delayed and difficult to predict early. Methods: We retrospectively analyzed 1308 patients (pts) with newly diagnosed AL from 2006 – 2015 to determine factors which could predict for OR. Results: Median age was 64 years (yr) and Mayo Stage was: 1 (22%); 2 (23%); 3 (25%); 4 (31%). Organ involvement was: cardiac (74%, n=932); renal (59%, n=738), liver (16%, n=205); gut (24%, n=310) and autonomic (12%, n=152). 59% (n=765) had > 1 organ involved, including 43% (n=567) with > 1 critical organ (heart, kidney, liver) involved. Treatment was: ASCT based (28%, n=330, N=1186), bortezomib based (24%, n=281), alkylator based (33%, n=392), others (5%, n=54) and none (10%). In evaluable pts, VGPR or better rates were: 53% at 6 months (m) (N=625), 72% at 12 m (N=465) and 57% overall (N=688). Table 1 lists OR at various time points. Complete OR in all involved critical organs was seen in: 51% (n=308, N=600), partial response (at least 1 OR when >1 organ involved) in 12% (n=73) and none in 37% (n=219). Complete OR was associated with better overall survival (OS) than partial or no OR (median OS: not reached vs 42 m vs 29 m; P <0.0001). In multivariate model the following variables at baseline or 1 yr mark were predictive of complete OR: lower Mayo Stage (p=0.01), fewer critical organs involved (p=0.007), higher baseline GFR (p=0.03), female sex (Complete OR 60% vs 47%; p=0.04) and VGPR at 1 yr (Complete OR 70% vs. 36%; p <0.0001). Other factors included in the model were age (p=0.9), bilirubin (p=0.1) and transplant (p=0.2). All aforementioned factors were significant in univariate analysis. Conclusions: Achievement of response in all involved critical organs is associated with better survival in AL pts than partial or no OR. Various baseline factors and VGPR at 1 yr can predict for achieving complete OR, with 70% pts who achieve VGPR at 1 yr having a complete OR.

*Including pts who died at landmark time-point ^#Excluding pts on dialysis at diagnosis