Weisel, K

e19503 Background: The anti-B-cell maturation antigen (BCMA) antibody-drug conjugate (ADC) belantamab mafodotin is approved in the USA and EU for relapsed/refractory multiple myeloma (RRMM). Understanding treatment options and patient outcomes following ADC failure is clinically important. This study describes post-ADC treatment patterns and clinical outcomes in real-world patients with RRMM. Methods: Adult patients with MM who received an ADC and initiated ≥1 subsequent line of therapy (LOT) were included. The index date was the start of the first post-ADC LOT. Data were obtained from chart reviews at International Myeloma Foundation International Myeloma Working Group (IMF IMWG) academic sites, and US electronic health records from largely community sites (COTA and Guardian Research Network [GRN]). Patient characteristics and index regimens were summarized descriptively. Time to next treatment (TTNT) and overall survival (OS) were estimated with the Kaplan-Meier estimator. Results: The IMF IMWG cohort (n=40) had a mean age of 70.8 years, median of 7 prior LOTs and 82.5% were triple-class refractory (TCR). Overall, 85% received ADC monotherapy (70% belantamab mafodotin) and 15% combination therapy. Pre-ADC and not considering corticosteroids, patients were commonly exposed to lenalidomide (R; 100%), bortezomib (V; 92.5%), daratumumab (D) and pomalidomide (P; 90% each). Over a median follow-up of 26 months after index date, 29 unique index post-ADC regimens were reported, frequently selinexor (27.5%) and bispecific antibodies (15%). CAR T-cell therapy was administered to 5%, with 60% re-treated with a pre-ADC drug class (PI/IMiD/anti-CD38) after ADC. Median (95% CI) TTNT and OS were 10.8 (7.0–20.6) and 19.0 (13.4–25.1) months, respectively. The COTA-GRN cohort (n=39) had a mean age of 67.5 years, median of 8 prior LOTs, and 51.3% were TCR. Overall, 56% received ADC monotherapy (belantamab mafodotin) and 44% combination therapy. Pre-ADC and not considering corticosteroids, patients were commonly exposed to D and R (97.4% each), and carfilzomib, V and P (94.9% each). Over a median follow-up of 9.2 months, 32 unique index post-ADC regimens were reported, frequently selinexor (23.1%) and venetoclax (17.9%) based; 0% received CAR Ts and 54% were re-treated with a pre-ADC drug class (PI/IMiD/anti-CD38) after ADC. Median (95% CI) TTNT and OS were 4.9 (2.8–non-estimable [NE]) and 12.0 (4.9–NE) months, respectively. Conclusions: Findings highlight that most patients with heavily pretreated BCMA-ADC exposed MM were re-treated with similar classes. Academic centers used novel therapies (ie, CAR T, bispecific antibodies) more often and their patients had longer survival than those treated at community sites. However, clinical outcomes remained sub-optimal, emphasizing the unmet need for effective, accessible post-ADC treatments.

Abstract Both the phase 3 MAIA and ALCYONE studies demonstrated significant survival benefit with the addition of daratumumab to standard-of-care Rd (Revlimid [lenalidomide] and dexamethasone; D-Rd) or to VMP (Velcade [bortezomib], melphalan, and prednisone; D-VMP), respectively, vs Rd or VMP alone in transplant-ineligible newly diagnosed multiple myeloma (NDMM). Patients with NDMM are highly susceptible to infection; therefore, gaining a greater understanding of infection incidence may help to mitigate future risk. We conducted a pooled analysis of infection incidence, timing, and management strategies from MAIA and ALCYONE. The median (range) age of the pooled population was 72 (40-93) years. Incidence was higher with D-Rd/D-VMP vs Rd/VMP for grade 3/4 (36.9% vs 22.4%) and grade 5 (3.0% vs 1.5%) infections; however, exposure-adjusted incidence rates were generally comparable between groups. Any-grade infections led to the discontinuation of study treatment in ∼2% of patients across treatment groups. Of the timing intervals explored, the highest incidence of grade 3/4 infection occurred within the first 6-month interval of study treatment initiation in both groups. Median time to the first onset of grade 3/4 infections (per Kaplan-Meier estimates) was 83.3 months and not estimable in the D-Rd/D-VMP and Rd/VMP groups, respectively. Although the rates of D-Rd/D-VMP treatment discontinuation due to infection remained low in MAIA and ALCYONE, clinicians should remain vigilant about infections throughout treatment and follow local guidelines and International Myeloma Working Group recommendations to minimize the risk of infection. These trials were registered at www.ClinicalTrials.gov as NCT02252172 (MAIA) and NCT02195479 (ALCYONE).