Isatuximab-Based Quadruplet Therapy Significantly Improves MRD Negativity in Newly Diagnosed Multiple Myeloma
核心洞察
The EMN24 IsKia phase 3 trial demonstrated that isatuximab plus carfilzomib, lenalidomide, and dexamethasone (Isa-KRd) significantly improved minimal residual disease negativity rates compared to KRd alone in transplant-eligible patients with newly diagnosed multiple myeloma (搜索).
At the primary endpoint, 77% of patients achieved MRD negativity at 10⁻⁵ sensitivity with Isa-KRd versus 67% with KRd (OR 1.67, P=0.049), with even greater benefit at 10⁻⁶ sensitivity (68% vs 48%, OR 2.36, P=0.0004).
The quadruplet regimen showed consistent MRD negativity benefits across all patient subgroups, including high-risk and ultra-high-risk patients, with particularly notable improvements in ultra-high-risk patients with 2+ high-risk cytogenetic abnormalities.
The addition of isatuximab to a carfilzomib-based triplet regimen significantly enhanced minimal residual disease (MRD) negativity rates in transplant-eligible patients with newly diagnosed multiple myeloma (搜索), according to results from the randomized phase 3 EMN24 IsKia trial published in Nature Medicine.
The study enrolled 302 transplant-eligible patients with newly diagnosed multiple myeloma (搜索) who were randomly assigned to receive either isatuximab plus carfilzomib, lenalidomide, and dexamethasone (Isa-KRd, n=151) or the triplet regimen alone (KRd, n=151). The median follow-up was 48 months from randomization.
Primary Endpoint Achievement
The trial met its primary endpoint, demonstrating that Isa-KRd significantly improved MRD negativity rates after post-autologous stem cell transplant (ASCT) full-dose consolidation. At the prespecified 10⁻⁵ sensitivity threshold, 77% of patients in the Isa-KRd arm achieved MRD negativity compared to 67% in the KRd arm (odds ratio 1.67, 95% CI 1.00-2.80, P=0.049).
The benefit was even more pronounced at the exploratory 10⁻⁶ sensitivity analysis, where 68% of Isa-KRd patients versus 48% of KRd patients achieved MRD negativity (OR 2.36, 95% CI 1.47-3.79, P=0.0004). Lead study author Dr. Francesca Gay from the University of Torino (搜索) noted that "the 10⁻⁶ cut-off is more informative than the 10⁻⁵ cut-off" in the context of highly effective regimens.
Rapid and Sustained Responses
MRD responses emerged rapidly, with significant benefits observed after just four induction cycles. The post-induction 10⁻⁵ MRD negativity rate was 46% with Isa-KRd versus 27% with KRd (OR 2.32, 95% CI 1.43-3.78, P=0.0007). At the 10⁻⁶ sensitivity level, the rates were 28% versus 14% respectively (OR 2.44, 95% CI 1.36-4.40, P=0.0029).
The advantage in sustained MRD negativity was maintained over time. One-year sustained 10⁻⁶ MRD negativity rates were 52% with Isa-KRd versus 38% with KRd (OR 1.82, 95% CI 1.14-2.91, P=0.012).
High-Risk Patient Benefits
Subgroup analyses revealed consistent MRD negativity benefits across all patient populations, including those with high-risk disease features. In ultra-high-risk patients with two or more high-risk cytogenetic abnormalities, the rates of 1-year sustained MRD negativity at 10⁻⁶ sensitivity were 62% with Isa-KRd versus 20% with KRd (OR 6.30, 95% CI 1.11-35.66).
For patients with International Myeloma Society/International Myeloma Working Group high-risk features, sustained 10⁻⁶ MRD negativity rates were 50% with Isa-KRd versus 26% with KRd (OR 2.84, 95% CI 1.00-8.11). Notably, the rates of sustained MRD negativity in high-risk, ultra-high-risk, and standard-risk patients treated with Isa-KRd were similar, suggesting the quadruplet regimen's ability to overcome adverse prognostic factors.
Treatment Protocol and Dosing
The Isa-KRd regimen consisted of carfilzomib at 20 mg/m² intravenously on day 1 of cycle 1, followed by 56 mg/m² on days 8 and 15 of cycle 1, then 56 mg/m² on days 1, 8, and 15 of subsequent cycles; lenalidomide 25 mg orally on days 1-21; dexamethasone 40 mg on days 1, 8, 15, and 22; and isatuximab 10 mg/m² with varying schedules across treatment phases.
Treatment included four 28-day induction cycles, followed by stem cell mobilization, autologous stem cell transplantation with melphalan 200 mg/m², four cycles of full-dose consolidation, and 12 cycles of light-intensity consolidation.
Safety Profile
The quadruplet regimen demonstrated a manageable safety profile. During light consolidation, the most common grade 3-4 adverse events in the Isa-KRd versus KRd arms included neutropenia (17% vs 17%), infections (10% vs 7%), and gastrointestinal toxicities (4% vs 5%).
Treatment discontinuation rates due to adverse events were similar between arms (8% vs 7%). The addition of isatuximab did not increase rates of cardiac and vascular toxicities, with vascular events including thrombosis and hypertension occurring in 5% of Isa-KRd patients versus 10% of KRd patients during induction and consolidation.
Stem Cell Collection
Stem cell mobilization was successful in both arms, with similar proportions proceeding to ASCT (89% vs 91%). The median number of CD34+ stem cells collected was 5.0 × 10⁶ cells/kg in the Isa-KRd arm versus 5.5 × 10⁶ cells/kg in the KRd arm (P=0.14).
Clinical Implications
The authors emphasized that these results support the potential role of carfilzomib in the upfront setting and provide evidence for anti-CD38 (搜索) monoclonal antibody plus carfilzomib-based combinations. "In the rapidly evolving treatment landscape of multiple myeloma (搜索), novel regimens based on KRd plus an anti-CD38 monoclonal antibody backbone upfront may represent valuable alternatives," the researchers concluded.
The study represents the first randomized trial investigating Isa-KRd versus KRd for upfront treatment of transplant-eligible patients with newly diagnosed multiple myeloma (搜索). While progression-free survival data require longer follow-up, the profound MRD negativity benefits, particularly in high-risk patients, suggest significant clinical potential for this quadruplet approach.