Prospective urinary albumin/creatinine ratio for diagnosis, staging, and organ response assessment in renal AL amyloidosis: results from a large cohort of patients.

OBJECTIVES: Quantification of 24 h-proteinuria is the gold standard for diagnosing, staging, and monitoring of patients with renal AL amyloidosis. However, 24 h-urine collection is cumbersome and may result in preanalytical error. In this prospective study, we investigated the role of urinary albumin/creatinine ratio (UACR) (cut-off: 300 mg/g) identifying renal involvement, evaluated a UACR-based staging system (UACR cut-off: 3,600 mg/g) and assessed whether UACR response (UACR decrease >30% without worsening in eGFR >25%) predicts renal outcome in 531 patients with newly-diagnosed AL amyloidosis. METHODS: From October 2013 paired 24 h-proteinuria and UACR (on first morning void) were measured in all newly-diagnosed patients with AL amyloidosis. Correlation between 24 h-proteinuria and UACR at baseline was assessed by Pearson's r test. Impact of UACR response on renal outcome was assessed in randomly created testing (n=354) and validation (n=177) cohorts. RESULTS: A strong linear correlation was found between 24 h-proteinuria and UACR at baseline (r=0.90; p<0.001). After a median follow-up of 31 months, 57 (11%) patients required dialysis. A UACR-based renal staging system identified three stages with significantly higher dialysis rate at 36 months comparing stage I with stage II and stage II with stage III. Achieving a renal response, according to a UACR-based criterion, resulted in lower dialysis rate in both testing and validation cohorts. CONCLUSIONS: UACR is a reliable marker for diagnosis, prognosis, and organ response assessment in renal AL amyloidosis and can reliably replace 24 h-proteinuria in clinical trials and individual patients' management.

Indicators of profound hematologic response in AL amyloidosis: complete response remains the goal of therapy.

In AL amyloidosis complete response (aCR) is defined as negative serum and urine immunofixation with normalized free light chain ratio (FLCR). However, achievement of low levels of involved FLC (iFLC) or difference between iFLC and uninvolved FLC (dFLC) are also relevant endpoints for treatment. We divided 434 consecutive patients with AL amyloidosis into five groups according to response 6 months after treatment initiation: aCR, iFLC <20 mg/L, normalized-iFLC, dFLC <10 mg/L, and normalized FLC ratio. Overall survival (OS) was similar (median not reached) in patients in aCR and in those who reached iFLC <20 mg/L, while it was inferior in all other groups (medians ranging from 79 to 91 months). Time to next therapy or death (TNTD) was longer in subjects attaining aCR (median 69 months) than in subjects reaching any FLC endpoint (medians ranging from 18 to 39 months). The ability of discriminating patients who survived more than 2 years among all responders was greater for current definition of aCR compared to combination of negative serum and urine immunofixation with any low-FLC endpoint. Complete response predicts best outcomes in AL amyloidosis and should be the goal of therapy if tolerability allows.

Sequential response-driven bortezomib-based therapy followed by autologous stem cell transplant in AL amyloidosis.

Autologous stem cell transplant (ASCT) is highly effective in selected patients with light chain (AL) amyloidosis. Bortezomib, preceding or following ASCT, improves responses. Satisfactory responses, including at least a partial response, very good partial response (VGPR) with organ response, or complete response, can be observed after induction therapy alone. We report 139 patients treated upfront with cyclophosphamide/bortezomib/dexamethasone (CyBorD), followed by ASCT only if response was unsatisfactory. Only 1 treatment-related death was observed. After CyBorD, hematologic response (HR) rate was 68% (VGPR or better, 51%), with 45% satisfactory responses. Transplant was performed in 55 (40%) subjects and resulted in an 80% HR rate (65% ≥ VGPR). Five-year survival was 86% and 84% in patients treated with ASCT or CyBorD alone, respectively (P = .438). Also, 6- and 12- month landmark analyses did not show differences in survival. Duration of response was not different in the 2 groups (60 vs 49 months; P = .670). Twenty-one (15%) patients with an unsatisfactory response to CyBorD could not undergo ASCT because of ineligibility or refusal; instead, they received rescue chemotherapy, with HR in 38% of cases and 51% 5-year survival. This sequential response-driven approach, offering ASCT to patients who do not attain satisfactory response to upfront CyBorD, is very safe and effective in AL amyloidosis.

High rate of profound clonal and renal responses with daratumumab treatment in heavily pre-treated patients with light chain (AL) amyloidosis and high bone marrow plasma cell infiltrate.

Daratumumab demonstrated activity in the treatment of AL amyloidosis in two recently concluded phase II clinical trials in relapsed and refractory patients. Its role in upfront therapy is under evaluation in a phase III study. In this report we evaluated the safety and efficacy of 28-day cycles of daratumumab (single agent or combined with bortezomib or lenalidomide) in 72 previously treated patients with multiple myeloma and AL amyloidosis. Fifty (69%) were refractory to the last line of therapy. After eight infusions of daratumumab, 59 patients (82%) achieved a hematologic response, with 12 (16%) complete responses (CRs) and 30 (42%) very good partial responses (VGPRs). After 16 infusions, the quality of response improved with 22 patients (30%) achieving CR and 21 (29%) attaining VGPR. Cardiac response was observed in 11 of 37 evaluable patients (29%) and renal response in 23 of 38 patients (60%). Daratumumab is highly effective in heavily pretreated patients with relapsed/refractory AL amyloidosis and high bone marrow plasma cell burden. Renal responses, which are usually rare in this setting, were frequently observed.