ELOQUENT-2 update: Phase III study of elotuzumab plus lenalidomide/dexamethasone (ELd) vs Ld in relapsed/refractory multiple myeloma (RRMM)—Identifying responders by subset analysis.

8037 Background: Extended follow-up of ELOQUENT-2 (NCT01239797) showed 27% reduction in risk of disease progression/death for ELd vs Ld and OS trend in favor of ELd (Dimopoulos M et al. ASH 2015; oral 28). We present subset analyses of extended 3-y follow-up. Methods: RRMM pts were randomized to ELd or Ld in 28-d cycles until disease progression/unacceptable toxicity (Lonial S et al. NEJM. 2015;373:621-31.). Coprimary endpoint: PFS. Key secondary endpoint: OS. Results: 646 pts randomized: 321 ELd, 325 Ld. Baseline demographics: median age 66 y; 32% of pts had del(17p), 9% t(4;14); median of 2 prior therapies; 35% refractory to last therapy. PFS and OS subset analyses shown in Table (data cut-off 13 Aug 2015). Median duration of response: ELd 20.3 vs Ld 16.6 mo. Conclusions: Subset analyses for ELd vs Ld were consistent with previous findings. PFS and OS benefit of ELd was seen across key subgroups, PFS benefit was durable over time. Clinical trial information: NCT01239797.PFS HR (95% CI) Median, mo (95% CI) ELd Ld Prior bortezomib Yes 0.68 (0.55–0.85) 18.5 (15.9–21.2) 12.9 (10.2–16.6) No 0.83 (0.58–1.21) 22.2 (16.6–30.3) 18.4 (13.9–22.9) Prior lenalidomide Yes 0.55 (0.24–1.25) 24.9 (12.0–NA) 7.4 (3.9–17.4) No 0.74 (0.61–0.91) 18.5 (16.5–22.2) 14.9 (12.3–17.5) del(17p)+ 0.70 (0.49–0.99); p = 0.042 21.2 (16.6–27.5) 14.9 (10.6–18.5) del(17p)- 0.73 (0.58–0.92); p = 0.007 18.5 (15.8–22.8) 14.8 (11.7–18.4) t(4;14)+ 0.52 (0.29–0.93); p = 0.027 15.8 (8.4–18.5) 5.6 (3.1–10.3) t(4;14)- 0.74 (0.60–0.91); p = 0.004 20.3 (17.3–23.3) 15.7 (13.0–18.5) Age < 65 y 0.74 (0.55–0.99); p = 0.043 19.4 (15.9–22.8) 16.6 (12.1–19.4) Age ≥ 65 y 0.72 (0.56–0.92); p = 0.009 18.5 (15.8–23.9) 13.9 (11.1–17.2) OS Risk High* 0.60 (0.37–0.97) 29.8 (22.2–NA) 24.8 (11.7–31.24) Low† 0.84 (0.28–2.52) NA (33.1–NA) 40.8 (35.2–NA) Standard 0.95 (0.72–1.26) 43.7 (40.1–NA) 47.6 (36.9–NA) del(17p)+‡ 0.66 (0.43–1.00) NA (35.8–NA) 36.4 (30.2–NA) del(17p)- 0.86 (0.66–1.14) 42.3 (36.7–NA) 40.8 (33.2–NA) Age < 65 y 0.77 (0.52–1.13) NA (42.9–NA) 40.9 (39.6–NA) Age ≥ 65 y 0.78 (0.58–1.03) 40.1 (30.5–NA) 32.2 (27.8–40.9) *ISS stage 2 or 3; t(4;14)+ or del(17p)+;†ISS stage 1 or 2; t(4;14)-, del(17p)- or 1q21-; age < 55 y; ‡≥ 1 cell del(17p)+