Background
Phase 3, open-label, randomized controlled trial (ELOQUENT-2). N=646 patients with relapsed or refractory multiple myeloma after 1–3 prior lines of therapy, including ≥1 prior line with lenalidomide. Randomized 1:1. Key eligibility: ECOG PS ≤2, no prior elotuzumab.
Interventions and follow up
Arm A (ERd): Elotuzumab 10 mg/kg IV (weekly cycles 1–2, then biweekly) + lenalidomide 25 mg PO (days 1–21) + dexamethasone 28–40 mg, 28-day cycles until progression.
Arm B (Rd): Lenalidomide 25 mg PO (days 1–21) + dexamethasone 40 mg PO, 28-day cycles until progression.
Primary endpoint: Progression-free survival
Median follow-up: 24.5 months
Arm B (Rd): Lenalidomide 25 mg PO (days 1–21) + dexamethasone 40 mg PO, 28-day cycles until progression.
Primary endpoint: Progression-free survival
Median follow-up: 24.5 months
Results
mPFS: 19.4 vs 14.9 months, HR 0.70 (95% CI 0.57–0.85), P<.001
1-yr PFS rate: 68% vs 57%
2-yr PFS rate: 41% vs 27%
ORR: 79% vs 66%
OS (4-year update): 50% vs 39% alive at 4 years, HR 0.78, P=.0408
1-yr PFS rate: 68% vs 57%
2-yr PFS rate: 41% vs 27%
ORR: 79% vs 66%
OS (4-year update): 50% vs 39% alive at 4 years, HR 0.78, P=.0408
Adverse events
Hematologic (ERd vs Rd): Grade ≥3 lymphocytopenia 77% vs 49%; grade ≥3 neutropenia 34% vs 44%.
Administration / constitutional: Infusion reactions any grade 10% (grade ≥3 1%); fatigue grade ≥3 8% vs 7%.
Discontinuation: Treatment discontinuation 20% vs 22%.
Administration / constitutional: Infusion reactions any grade 10% (grade ≥3 1%); fatigue grade ≥3 8% vs 7%.
Discontinuation: Treatment discontinuation 20% vs 22%.
Conclusions
Elotuzumab added to Rd (ERd) significantly improved PFS (HR 0.70) and demonstrated a 4-year OS benefit (HR 0.78) in relapsed myeloma, establishing elotuzumab as the first immunostimulatory antibody (anti-SLAMF7) approved for myeloma when combined with an IMiD.
Key Limitations
The PFS benefit was modest in absolute terms (4.5-month median improvement). Elotuzumab monotherapy showed no activity — all benefit requires IMiD combination. In the current era with widespread prior lenalidomide and anti-CD38 exposure, the population eligible for ERd is shrinking. The mechanism (SLAMF7-directed NK and T-cell activation) does not directly kill myeloma cells but requires an intact immune system, potentially limiting efficacy in heavily pretreated or immunocompromised patients.
Clinical Context
FDA approved elotuzumab + Rd in 2015 for RRMM. Subsequent phase 3 data showed elotuzumab + pomalidomide + dex (EPd) benefit in 2–3 prior lines (ELOQUENT-3). ASCO and ESMO guidelines list elotuzumab-based combinations among relapse options. ERd is now largely reserved for lenalidomide-naïve RRMM or used when anti-CD38 access is limited; the modest PFS benefit (HR 0.70) makes it less compelling than anti-CD38 combinations (daratumumab, isatuximab) in this setting.