Spencer, Andrew

Abstract Multiple myeloma (MM) is a heterogenous cancer that remains mostly incurable. A unifying feature of MM cells is a highly interconnected network of transcription factors and co-factors that coordinate the activity of super-enhancers to enforce myeloma cell identity. Targeting this network offers a promising avenue for therapeutic intervention across genetically diverse myeloma sub-types. Using integrated molecular and functional genomic approaches we identified Menin as a key driver of oncogenic gene expression in MM cells. Menin and its co-factor KMT2A bind at super-enhancers and maintain expression of essential myeloma genes, including IRF4. We demonstrate that Menin inhibitors, which have recently been approved for treatment of acute myeloid leukaemia, are highly active in myeloma cell lines and in vivo models. Combining Menin inhibitors with other super-enhancer targeting therapies such EP300/CREBBP inhibitors or immunomodulatory drugs (IMiDs) overcomes epigenetic plasticity in cells resistant to single agent treatment.

7516 Background: With the growing use of anti-CD38 therapies in early multiple myeloma (MM) management, there is a need for data in patients previously exposed to anti-CD38 therapy to guide decision making. In the Phase 3 IRAKLIA trial (NCT05405166), patients with relapsed/refractory MM (RRMM) received the anti-CD38 monoclonal antibody isatuximab (Isa) subcutaneously (SC) delivered via an innovative on-body injector (OBI) or intravenously (IV), with pomalidomide and dexamethasone (Pd). In this post hoc analysis, we examined outcomes in IRAKLIA patients with vs without prior anti-CD38 exposure. Methods: RRMM patients ≥18 years with ≥1 prior line of therapy including lenalidomide and a proteasome inhibitor were randomized to receive Isa SC (n=263) or IV (n=268) weekly in Cycle 1, then every 2 weeks, with Pd. Patients with prior anti-CD38 exposure <9 months (mos) before randomization or intolerance to anti-CD38 were excluded. Refractory patients were defined as those who failed to achieve minimal response on treatment or had progression within 60 days after last dose. Patients receiving Isa SC or IV were pooled. Results: Overall, 67 patients (12.6%) had prior anti-CD38 exposure with a median washout period of 20.2 mos, of which 26 (38.8%) were anti-CD38 refractory. Baseline characteristics were largely consistent between patients with or without prior anti-CD38 exposure; the median follow-up for the overall population was 12 mos. Patients with prior anti-CD38 exposure had an overall response rate (ORR) of 52.2%, 12-mo progression-free survival (PFS) rate of 40.6%, and median PFS of 8.5 mos. In patients without prior exposure, an ORR of 73.5%, 12-mo PFS of 68.8%, and non-estimable (NE) median PFS were reported. Anti-CD38 non-refractory vs refractory patients had an ORR of 48.8% vs 57.7%, 12-mo PFS of 38.9% vs 42.2%, and median PFS of 9.0 vs 7.5 mos. Patients with a longer washout period (>median of 20.2 mos) had an ORR of 63.6%, 12-mo PFS of 61.8% and NE median PFS, whereas patients whose prior anti-CD38 therapy ended more recently (≤median of 20.2 mos) had an ORR of 41.2%, 12-mo PFS of 19.2%, and median PFS of 6.7 mos. The safety profile of Isa + Pd was similar in patients with vs without prior anti-CD38 exposure. Conclusions: Isa + Pd demonstrated clinical benefit across anti-CD38–naïve, anti-CD38–exposed, and anti-CD38–refractory patients. A washout period >median of 20.2 mos resulted in outcomes comparable to those in anti-CD38–naïve patients, and outcomes were consistent between anti-CD38–exposed and anti-CD38–refractory patients after a >9-mo washout period. Efficacy of Isa + Pd in patients with prior anti-CD38 exposure from the IRAKLIA trial presents an opportunity to address an unmet need in a difficult-to-treat patient population. Clinical trial information: NCT05405166 .

Abstract The B-cell maturation antigen (BCMA)–targeting bispecific T-cell engager pavurutamab (AMG 701) directs the cytotoxic T-cell response toward multiple myeloma (MM) cells. This phase 1/1b, open-label, dose-exploration and dose-expansion study evaluated the safety, tolerability, and efficacy of pavurutamab monotherapy in patients with triple-class relapsed/refractory MM (RRMM). Pavurutamab (5-18 000 μg) was administered IV weekly with step-up dosing in week 1. Overall, 172 patients received at least 1 dose of pavurutamab; 73 received the recommended phase 2 dose (RP2D; 18 000 μg), with 2 different step-up dosing regimens in phase 1b. Twelve patients had dose-limiting toxicities, which included cytokine release syndrome (CRS) and increased transaminases; none of which occurred at the RP2D. The most frequently reported treatment-emergent adverse events included CRS (74.4%), anemia (61.0%), neutropenia (47.1%), and hypophosphatemia (45.3%). Grade ≥3 infections were noted in 60 patients (34.9%). The overall response rate (ORR) was 46.5% among all patients and 65.8% (very good partial response [VGPR] or better, 60.3%) among 73 patients treated at the RP2D. At median follow-up of 17.2 months, median duration of response (DOR) was 36.6 months (95% confidence interval [CI], 22.3 to not estimable). Median progression-free survival (PFS) for all patients was 5.5 months (95% CI, 2.8-10.1) and 16.8 months (95% CI, 5.0 to not estimable) with the RP2D. Pavurutamab exposure generally increased in a dose-proportional manner, with high soluble BCMA levels correlating with lower exposure level. The acceptable safety profile, pharmacokinetics, and preliminary efficacy of pavurutamab supports anti-BCMA T-cell engager therapy in heavily pretreated patients with RRMM. This trial was registered at www.clinicaltrials.gov as NCT03287908.