Chen, GuiZhen

Abstract Rapid and profound reduction of free light chains (FLCs) improves outcomes in AL amyloidosis; however, early FLC kinetics with daratumumab‐based frontline therapy remain undefined. We retrospectively analyzed 315 patients treated with daratumumab–bortezomib–cyclophosphamide–dexamethasone (Dara–VCd) or Dara–Vd at eight centers. Involved FLC (iFLC), the difference between iFLC and uninvolved FLC (dFLC), and hematologic response (≥very good partial response [VGPR]) were assessed at baseline and at 1, 3, and 6 months, and correlated with light chain isotype, disease burden (bone‐marrow plasma‐cell percentage [%BMPC], baseline dFLC), and cytogenetics. Hematological ≥VGPR increased from 49.8% at 1 month to 66.0% at 3 months. The kappa isotype showed slower responses, with higher iFLC/dFLC and lower ≥VGPR at each time point compared to lambda. Higher %BMPC or baseline dFLC predicted persistently elevated iFLC/dFLC and reduced ≥VGPR. The t(11;14) translocation was associated with lower baseline FLC but similar subsequent kinetics. BMPC < 10% and dFLC < 18 mg/dL independently predicted early ≥VGPR (in ≤1 month). Early ≥VGPR conferred superior hematologic event‐free survival (heme‐EFS) and overall survival (OS) versus later responders (P < 0.001). At a 3‐month landmark, achieving dFLC < 1 mg/dL further stratified prognosis, conferring longer heme‐EFS and OS (P < 0.01). Frontline Dara‐based therapy elicits rapid, deep responses in AL amyloidosis; early ≥VGPR (within 1 month) and dFLC < 1 mg/dL by 3 months predict durable EFS and OS, whereas higher baseline disease burden delays hematologic response.

Abstract We performed an international retrospective study on 283 patients with light chain (AL) amyloidosis to investigate the prognostic impact of cytogenetic abnormalities by fluorescence in situ hybridization, when treated with frontline daratumumab–based therapy. The cytogenetic subgroups of interest were t(11;14), gain/amp(1q) (hereafter, +1q), hyperdiploidy, deletion(13q), del(17p), and myeloma high-risk (HR) translocations (t[4;14], t[14;16], or t[14;20]). The end points of interest were rate of hematologic complete response (heme-CR), very good partial response (VGPR) or better, and hematologic event-free survival (heme-EFS). The incidence of abnormalities was as follows: t(11;14), 53.4%; deletion (13q), 28.9%; +1q, 22.3%; hyperdiploidy, 19.4%; HR translocations, 6.6%; and deletion(17p), 4.5%. The heme-CR rate by cytogenetic subgroups were as follows: t(11;14) vs no t(11;14), 45.2% vs 41.8% (P=0.597); del(13q) vs no del(13q), 46.8% vs 42.8% (P=0.594); +1q vs no +1q, 30.2% vs 47.9% (P=0.022); hyperdiploidy vs no hyperdiploidy, 39.5% vs 44.9% (P=0.541); HR translocations vs none, 45.5% vs 43.1% (P=0.877); and del(17p) vs no del(17p), 50.0% vs 42.9% (P=0.658), respectively. Similarly, +1q was the only subgroup with a significantly lower VGPR or better rate (64.2% vs 79.0%; P=0.033). At a median follow-up of 19.8 months, the median heme-EFS was 49.6 months (95% CI, 24.7-not reached [NR]), and the 2-year overall survival (OS) was 80.98% (95% CI, 75.6-85.4). The presence of +1q was significantly associated with worse heme-EFS on multivariate analysis (HR 2.06, 95% CI, 1.14-3.71; P=0.017). Notably, there was no adverse prognostic impact of t(11;14) on heme-EFS or OS. In conclusion, +1q is associated with worse outcome in the daratumumab-era. Clinical trials testing novel frontline immunotherapies should be enriched in +1q to further improve outcomes in this subgroup.