Loi, Matteo

7569 Background: MAIA and CEPHEUS trials demonstrated that daratumumab (Dara) with standard of care (SOC) VRd or Rd significantly improved clinical outcomes versus SOC in TIE NDMM. Here we describe efficacy and safety in TIE pts from both trials by age and baseline (BL) frailty using the latest data cuts. Methods: Pts were randomized 1:1 to DRd (n=368) or Rd (n=369) in MAIA and 1:1 to DVRd (n=144) or VRd (n=145) in CEPHEUS. Progression-free survival (PFS), complete response or better (≥CR), overall MRD negativity (neg) at 10 -5 with ≥CR, sustained MRD neg with ≥CR (confirmed MRD neg ≥12 ± 1 months [mo] apart without MRD positivity in between), and safety were assessed by age (<70, 70–<75, or ≥75 years [y]) and BL frailty (assessed by IFM simplified frailty score: 0–1, non-frail; ≥2, frail). Results: Median follow-up was 64.5 mo in MAIA and 76.0 mo in CEPHEUS. In MAIA, 155 (21%) pts were <70 y, 261 (35%) 70–<75 y, and 321 (44%) ≥75 y; 341 (46%) pts were frail, 88.0 % of whom were ≥70 y. In CEPHEUS TIE pts, 70 (24%) pts were <70 y, 133 (46%) 70–<75 y, and 86 (30%) ≥75 y; 83 (29%) pts were frail, 86% of whom were ≥70 y. DRd or DVRd improved PFS, MRD neg rates, sustained MRD neg rates, and ≥CR rates vs Rd or VRd arms across age and frailty subgroups in both trials (Table). Safety was consistent with established individual drug profiles, and adverse event rates were generally comparable across treatment arms and subgroups within both trials. Additional data on patient-specific factors relevant to these subgroups will be presented. Conclusions: Dara-based regimens improved efficacy outcomes across subgroups in MAIA and CEPHEUS trials, reinforcing Dara-based regimens as SOC in TIE NDMM regardless of age or frailty. These data offer clinically relevant insights to help guide treatment selection for TIE pts. Clinical trial information: NCT03652064 ; NCT02252172 . PFS, hazard ratio (95% CI) ≥CR rate, % MRD neg with ≥CR (10 -5 ) rate, % Sustained MRD neg with ≥CR (10 -5 ) rate, % Age/ Frailty status MAIA* CEPHEUS** MAIA* CEPHEUS ** MAIA* CEPHEUS** MAIA* CEPHEUS ** <70 y 0.35 (0.21–0.56) 0.60 (0.31–1.18) 56.4 vs 31.2 85.7 vs 68.6 35.9 vs 11.7 74.3 vs 42.9 25.6 vs 3.9 62.9 vs 28.6 70–<75 y 0.64 (0.45–0.89) 0.60 (0.37–0.99) 56.2 vs 31.3 77.9 vs 69.2 36.2 vs 12.2 55.9 vs 47.7 20.8 vs 5.3 45.6 vs 38.5 ≥75 y 0.59 (0.44–0.79) 0.46 (0.22–0.94) 44.4 vs 28.6 80.5 vs 44.4 26.9 vs 9.9 58.5 vs 26.7 13.8 vs 3.1 43.9 vs 15.6 Frail 0.64 (0.48–0.85) 0.62 (0.32–1.18) 44.8 vs 33.1 72.9 vs 54.3 25.6 vs 13.0 56.3 vs 34.3 15.7 vs 4.1 39.6 vs 17.1 Non-frail 0.48 (0.36–0.64) 0.51 (0.34–0.78) 56.6 vs 27.5 84.4 vs 63.6 37.8 vs 9.5 63.5 vs 41.8 21.4 vs 4.0 54.2 vs 32.7 *MAIA: DRd vs Rd; **CEPHEUS: DVRd vs VRd.

Abstract Introduction AL amyloidosis is a rare disorder caused by amyloid fibrils produced by clonal plasma cells, leading to serious organ dysfunction. Cardiac involvement is a major risk factor for poor survival. CD38-binding Daratumumab (D) targets plasma cells and, with bortezomib, cyclophosphamide and dexamethasone (VCd) is the only approved regimen for newly diagnosed AL amyloidosis. The ANDROMEDA phase 3 study showed significant improvements in hematologic responses, major organ deterioration progression free survival and overall survival, compared with VCd alone. The AQUARIUS study (NCT05250973) evaluated cardiac safety of different D-VCd schedules and potential cardiac toxicity mitigation strategies. Methods This multicenter, open-label, phase 2 study enrolled 151 newly diagnosed AL amyloidosis patients at 37 sites in 10 countries. Patients enrolled in either Cohort 1 (n=120, cardiac involvement [Mayo 2004 stage II/IIIA], randomized 2:1 to receive D + immediate VCd or D + deferred VCd) or Cohort 2 (n=31, racial or ethnic minorities with ≥1 any organ involvement, treated with D + immediate VCd). Immediate VCd began on Cycle 1, deferred VCd on Cycle 4. The primary safety endpoint was the incidence of cardiac treatment emergent adverse events (TEAEs). Cardiac assessments included HS TroponinT, NT-proBNP, echocardiogram (ECHO), ECG, NYHA, and the 6-minute walk test (6MWT). Clinical cardiac signs and symptoms (S&S) were assessed at baseline and monthly. Selected, clinically relevant grade ≥3 and/or serious cardiac TEAEs were defined as Major Cardiac TEAE and were assessed by an independent adjudication committee for causality. Patients were followed for 12 treatment cycles or 12 months from first dose (if treatment discontinued prior to 12 cycles). Results 142 patients from both cohorts had cardiac involvement and received at least one dose of D + immediate VCd (n=103) or D + deferred VCd (n=39). Baseline characteristics were balanced between the two groups, including Mayo 2004 stage (IIIa: immediate VCd, 35.0%; deferred VCd, 35.9%; II: immediate VCd, 62.1%; deferred VCd, 53.8%). Treatment duration (median: 10.4 months) and proportion completing ≥10 cycles (79% vs 85%) were similar. Serious cardiac TEAEs occurred at similar rates across groups (immediate VCd, 7.8%; deferred VCd, 7.7%). The most common serious cardiac TEAE (MedDRA term) was cardiac failure (immediate VCd, 5.8%; deferred VCd, 2.6%). Two deaths occurred within 60 days of first study treatment, both were in the immediate VCd group, cardiac-related and unrelated to treatment. The immediate VCd group had fewer cardiac TEAEs overall (48.5% vs 61.5%) but experienced them more frequently during Cycles 1-3 than deferred VCd (35.9% vs 28.2%). This trend reversed for Cycles 4-6 (immediate VCd, 17.7%; deferred VCd, 28.9%). Cardiac TEAEs were low for both groups for Cycles 7-9 (immediate VCd, 9.3%; deferred VCd, 12.1%) and Cycles 10-12 (immediate VCd, 7.4%; deferred VCd, 12.1%). Levels of NT-proBNP, HS troponin T, the 6MWT, and overall cardiac S&S improved similarly for both treatment groups. Rate of cardiac TEAEs of any grade was similar for Mayo stage III patients in the two groups (immediate VCd, 73.0%; deferred VCd, 68.8%) whereas for Mayo stage II patients the incidence was higher in the deferred group (35.9% vs 57.1%). Twenty patients (Immediate VCd, 13; deferred VCd, 7) experienced 30 Major Cardiac TEAEs (selected grade ≥3 and/or serious). Adjudicators attributed 28 events primarily to amyloid cardiomyopathy and 2 events primarily to treatment. These 20 patients had higher baseline Mayo stage (IIIa: 70% vs 29.5%) than the remaining patients (n=122), higher baseline median NT-proBNP (4862 ng/L vs 1723 ng/L) and overall S&S score (7.5 vs 4.0). Several ECHO measures were worse at baseline in these 20 patients (notably, median GLS: -8.8% vs -13.7% and E prime lateral: 4.4 cm/s vs 6.1 cm/s) as was 6MWT (median distance: 319 m vs 363 m). Complete Response (CR) rates were similar in both groups: immediate VCd, 62.1%; deferred VCd, 59.0%. Median time to CR was 64 days for the immediate VCd group and 113 days for the deferred VCd group. Conclusion The D-VCd regimen (immediate or deferred) had a manageable safety profile consistent with previous studies. Cardiac TEAEs were similar between regimens, and their emergence correlated with the start of VCd. Major cardiac events were associated with underlying disease and baseline risk factors that are quantifiable and monitorable.