Weisel, Katja C

PURPOSE ABBV-383, a B-cell maturation antigen × CD3 T-cell engaging bispecific antibody, has demonstrated promising results in an ongoing first-in-human phase I study (ClinicalTrials.gov identifier: NCT03933735 ) in patients with relapsed/refractory multiple myeloma (RRMM). Herein, we report safety and efficacy outcomes of this phase I dose escalation/expansion study. METHODS Patients with RRMM (≥ three prior lines including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody) were eligible. ABBV-383 was administered intravenously over 1-2 hours once every 3 weeks, without any step dosing. A 3 + 3 design with backfilling for dose escalation was used (intrapatient escalation to highest safe dose permitted) followed by initiation of dose expansion. RESULTS As of January 8, 2022, 124 patients (dose escalation [0.025-120 mg], n = 73; dose expansion [60 mg], n = 51) have received ABBV-383; median age was 68 years (range, 35-92 years). The most common hematologic treatment-emergent adverse events (TEAEs) were neutropenia (all grades: 37%) and anemia (29%). The most common nonhematologic TEAEs were cytokine release syndrome (57%) and fatigue (30%). Seven deaths from TEAEs were reported with all considered unrelated to study drug by the investigator. For all efficacy-evaluable patients (n = 122; all doses), the objective response rate (ORR) was 57% and very good partial response (VGPR) or better (≥ VGPR) rate was 43%. In the 60 mg dose expansion cohort (n = 49), the ORR and ≥ VGPR rates were 59% and 39%, respectively; and in the ≥ 40 mg dose escalation plus dose expansion cohorts (n = 79) were 68% and 54%, respectively. CONCLUSION ABBV-383 in patients with RRMM was well tolerated with an ORR of 68% at doses ≥ 40 mg. This novel therapy's promising preliminary antitumor activity in heavily pretreated patients warrants further clinical evaluation.

8044 Background: In the phase 3 MAIA study, adding DARA to Rd improved progression-free survival (primary endpoint), overall survival, duration of response, and PROs in transplant-ineligible pts with NDMM. We report a MAIA subgroup analysis of time to response, duration of response, and PROs. Methods: Transplant-ineligible pts with NDMM received 28-day cycles of Rd (R 25 mg PO on Days 1-21; d 40 mg PO QW) ± DARA (16 mg/kg IV QW in Cycles 1-2, Q2W in Cycles 3-6, and Q4W thereafter) until disease progression or unacceptable toxicity. Secondary endpoints included time to response and duration of response. PROs were measured using the EORTC QLQ-C30, with treatment effects assessed via mixed-effects model with repeated measures. Results: In total, 368 pts were assigned to the D-Rd group and 369 pts to the Rd group; 162 (44%) D-Rd pts and 142 (38%) Rd pts had renal impairment (defined as baseline CrCl ≤60 mL/min). At a 56.2-mo median follow-up, median times to very good partial response or better (≥VGPR) and complete response or better (≥CR) were shorter with D-Rd vs Rd in the overall study population and in the subgroups of pts with and without renal impairment (Table). Among pts who achieved ≥CR or partial response or better (≥PR), higher proportions of D-Rd vs Rd pts had not experienced disease progression at 48 mo (Table). Among pts with renal impairment, greater improvements from baseline in pt-reported pain, fatigue, and nausea and vomiting symptom scores were observed with D-Rd vs Rd across most timepoints; a notably greater meaningful reduction in pain symptom score was seen with D-Rd vs Rd as early as Cycle 6 Day 1 (least squares mean change from baseline, −14.9 vs −7.0; P=0.0241). Analyses for additional pt subgroups will be presented. Conclusions: In transplant-ineligible pts with NDMM, D-Rd showed more rapid deep responses as well as more durable responses vs Rd, regardless of renal function. Improvements in pt-reported symptoms were generally greater with D-Rd vs Rd in pts with renal impairment. Our results support the use of D-Rd in transplant-ineligible pts with NDMM. Clinical trial information: NCT02252172. [Table: see text]

Summary: The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.