P901: POMALIDOMIDE, BORTEZOMIB, AND DEXAMETHASONE IN LENALIDOMIDE–PRETREATED MULTIPLE MYELOMA: A SUBANALYSIS OF OPTIMISMM BY FRAILTY

Background: Patients (pts) with multiple myeloma (MM) are likely to be older adults, and advanced age is associated with lower survival rates, in part due to comorbidities and frailty. Results from the phase 3 OPTIMISMM trial (NCT01734928) demonstrated that pomalidomide (P) in combination with bortezomib + dexamethasone (Vd) significantly improved progression-free survival (PFS) in lenalidomide (LEN)–pretreated pts with relapsed/refractory MM (RRMM) vs Vd, irrespective of age and Eastern Cooperative Oncology Group performance status (ECOG PS). Aims: Here, we report results from a post hoc analysis assessing outcomes of PVd vs Vd in pts with RRMM by frailty status. Methods: Pts with MM and 1–3 prior lines of therapy (including a LEN-containing regimen) who had been randomized 1:1 to PVd or Vd were assessed for frailty. Frailty scores were calculated using age (≤ 75 yr = 0; 76–80 yr = 1; > 80 yr = 2), the Charlson Comorbidity Index (≤ 1 = 0; > 1 = 1), and ECOG PS (0 = 0; 1 = 1; ≥ 2 = 2). Pts were classified as non-frail (NF; combined score: 0 or 1) or frail (F; combined score: ≥ 2). PFS, overall response rate (ORR), and safety outcomes were assessed by treatment group and frailty status. Results: In the intent-to-treat population (N = 559) (data cut-off Oct 26, 2017), 93/281 (33.1%) pts who received PVd and 93/278 (33.5%) who received Vd were frail. Baseline characteristics were similar between treatment groups within each frailty subgroup. Median PFS was longer with PVd vs Vd in NF (P = 0.001) and F (P = 0.006) subgroups (Table). ORR was higher with PVd vs Vd in NF (P < 0.001) and F (P < 0.001) subgroups. Incidence of grade ≥ 3 (G3) treatment-emergent adverse events (TEAEs) was higher with PVd vs Vd in NF (88.1 vs 61.3%) and F (96.8 vs 87.9%) subgroups; peripheral neuropathy, acute renal failure, and hypertension were the most common. Treatment discontinuation due to G3 TEAEs was greater with PVd vs Vd in NF (19.2 vs 18.5%) and F (30.1 vs 20.9%) subgroups. PVd had a longer median treatment duration vs Vd in NF (8.8 vs 5.7 mo) and F (8.9 vs 4.3 mo) subgroups. Image:Summary/Conclusion: Frail pts with RRMM who received PVd had longer PFS and higher ORR than pts who received Vd, consistent with the overall OPTIMISMM results. Frail pts experienced more G3 TEAEs and treatment discontinuations with PVd vs Vd, but treatment duration was longer with PVd vs Vd.