Long-Term Outcomes and Health-Related Quality of Life (HRQoL) By Response Status for Bortezomib, Melphalan, and Prednisone (VMP) ± Daratumumab (DARA) in Alcyone

Introduction: DARA is a human IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action. In the phase 3 ALCYONE study (median follow-up of 40.1 months), DARA in combination with VMP (D-VMP) reduced the risk of disease progression or death by 58% versus VMP alone (median 36.4 vs 19.3 months; HR, 0.42; 95% CI, 0.34-0.51; P<0.0001) and demonstrated a significant overall survival (OS) benefit (median not reached in either group; HR, 0.60; 95% CI, 0.46-0.80; P=0.0003) for patients (pts) with transplant-ineligible newly diagnosed multiple myeloma (TIE NDMM). Here, we report the results of a subgroup analysis examining long-term efficacy outcomes and HRQoL based on response status for D-VMP versus VMP, at a median follow-up of 40.1 months.

Methods: Pts with TIE NDMM were randomized 1:1 to receive up to nine 6-week cycles of VMP (V 1.3 mg/m² SC on Days 1, 4, 8, 11, 22, 25, 29, and 32 of Cycle 1 and Days 1, 8, 22, and 29 of Cycles 2-9; M 9 mg/m² PO on Days 1-4 of Cycles 1-9; and P 60 mg/m² PO on Days 1-4 of Cycles 1-9) ± DARA (16 mg/kg intravenously once weekly (QW) for Cycle 1 and Q3W for Cycles 2-9). Pts in the D-VMP group received DARA as maintenance therapy Q4W for Cycles 10+ until disease progression or unacceptable toxicity. The primary endpoint was PFS. Secondary endpoints included overall response rate (ORR), rate of ≥CR, rate of ≥very good partial response (VGPR), MRD-negativity rate (10^–5), OS, and HRQoL. Outcomes were also examined at the time of best response at the beginning of DARA monotherapy (Cycle 10+) and 1 and 2 years after beginning DARA monotherapy.

Results: A total of 706 (D-VMP, n=350; VMP, n=356) pts were randomized. Baseline characteristics were well balanced between groups. After a median follow-up of 40.1 months, D-VMP increased the ORR (90.9% vs 73.9%) and the rates of ≥CR (46% vs 25%), ≥VGPR (73% vs 50%), MRD-negativity (28% vs 7%; all P<0.0001), and ≥CR with MRD-negativity (27% vs 7%) vs VMP. PFS, OS, and time to subsequent therapy were prolonged for pts with deeper responses in both groups. A PFS benefit with D-VMP vs VMP was observed in pts with a best response of PR, VGPR, and ≥CR; all patients who achieved ≥CR with MRD-negativity demonstrated prolonged PFS, regardless of treatment (Figure). Time to subsequent therapy was improved in pts treated with D-VMP vs VMP across response categories, particularly among patients with a best response of VGPR (median 43.8 vs 27.5 months), ≥CR (median NR vs 44.4 months), and ≥CR with MRD-negativity (median NR vs 44.4 months). A trend toward improved OS was observed with D-VMP vs VMP across response categories. For pts achieving the deepest response (≥CR with MRD-negativity; D-VMP n=94 [26.9%], VMP n=25 [7.0%]) 36-month OS rates were high (89.3% D-VMP vs 96.0% VMP). Clinically meaningful improvements in HRQoL were observed with both D-VMP and VMP during the study across response categories. In the pooled study population, global health status (GHS) improved with deepening responses at month 12 (mean change from baseline ≥PR, 11.11; ≥VGPR, 13.19; ≥CR, 14.48; ≥CR with MRD-negativity, 15.81). In addition to the large improvements from baseline during treatment for GHS, there was a general trend towards a greater percentage of D-VMP patients achieving a meaningful improvement in pain (≥PR, 48.7%; ≥VGPR, 55.7%; ≥CR, 68.9%; ≥CR with MRD-negativity, 71.2%) and fatigue (≥PR, 56.4%; ≥VGPR, 54.1%; ≥CR, 59.7%; ≥CR with MRD-negativity, 63.0%) as clinical response deepened.

For patients in the D-VMP group who received DARA monotherapy in Cycle 10+, responses continued to deepen: rates of ≥CR improved from 44% at the beginning of maintenance to 64% and 68% at 1 and 2 years, respectively, after the start of DARA maintenance therapy. As in the full study population, improved PFS and OS were observed with deepening responses.

Conclusions: D-VMP induced deep responses in TIE NDMM pts and improved PFS, regardless of response status. Depth of response improved PFS, OS, and time to subsequent therapy and responses continued to deepen for patients receiving DARA maintenance therapy. HRQoL was improved in both treatment groups over the course of the study as clinical response deepened. These findings suggest that the addition of DARA to VMP achieves and maintains deep responses for TIE NDMM pts, leading to better outcomes and HRQoL.