Lonial, Sagar

Background: Dex is a key component of induction regimens for NDMM despite common toxicities including insomnia and anxiety. The E4A03 randomized trial (Rajkumar, Lancet Oncol 2010) demonstrated that dex dosed at 40 mg weekly outperformed higher-intensity dex and established this regimen as the standard of care for NDMM. In standard practice as well as clinical trials, however, dex doses are often reduced to 20 mg weekly or lower (if not stopped entirely) among older patients or among patients experiencing toxicities. As a first step toward establishing the equipoise of planned dex dose reductions in NDMM, we investigated outcomes with patients from two previous SWOG trials to understand the impact of dex dose reductions on post-induction outcomes. Methods: This was a secondary analysis of data from two completed NDMM studies, S0777 (comparing VRd vs Rd) and S1211 (comparing Elo-VRd vs VRd). For this secondary analysis, we analyzed the subset of patients who completed all eight 3-week cycles of induction (or six 4-week cycles in the S0777 Rd arm). As shown in Figure 1A, we defined DEX fullDose as patients for whom the starting dex dose (either 40 mg once per week or 20 mg on Days 1, 2, 4, 5, 8, 9, 11, and 12 of 21-day cycles) did not change during induction. In contrast, DEX lowered was defined as patients for whom the end-of-induction dex dose and/or frequency were lower than their starting values. As an exploratory analysis, we also compared PFS and OS between the DEX fullDose (no changes to dex strength during induction) and DEX veryLow (dex dosing reduced ≥50% during induction) subgroups. All analyses were landmarked from the end of induction, defined as 24 weeks from registration, to account for the time-dependent nature of dex treatment received. Survival curves were based on the Kaplan-Meier method and comparisons were made using the log-rank test. Results: Of 541 evaluable patients ( n = 441 from S0777, n = 100 from S1211), dex was reduced during induction in 76% ( n = 410). Compared to DEX fullDose patients, DEX lowered patients were more likely to be anemic (37% vs 26%, p = 0.02) but had similar distributions of age ≥70 (24% of DEX lowered vs 26% of DEX fullDose), Performance Status > 1 (15% vs 12%), ISS stage 3 disease (33% vs 27%), ≥ 60% bone marrow plasma cell burden (37% vs 31%), M-spike > 3 g/dL (48% vs 48%) platelets < 150,000 cells/mm 3 (18% vs 14%), baseline LDH ≥ 190 U/L (36% vs 41%), and baseline CRP ≥ 8 mg/L (27% vs 30%). PFS (Figure 1B) was comparable between DEX lowered (median 36 months, 95% CI 29 to 39 months) and DEX fullDose (median 33 months, 95% CI 24 to 48 months) with p = 0.90. Similarly, OS (Figure 1C) was comparable between DEX lowered [median 77 months, 95% CI 68 months to not reached (NR)] and DEX fullDose (median 92 months, 95% CI 65 months to NR) with p = 0.93. In the DEX veryLow subgroup with ≥50% reduction in dex dosing during induction, median PFS was 39 months (95% CI 34 to 50 months) and median OS was NR (95% CI NR to NR). As shown in Figure 1D and Figure 1E, PFS and OS were comparable between these patients and DEX fullDose patients. Discussion: To our knowledge, this is the first analysis of dex dosing strength in NDMM since E4A03. In two separate randomized trials, over half of patients required dex reductions below a starting dose of ~40 mg weekly. Dex dose reductions during induction had no impact on post-induction PFS and OS, even in the subset of patients who required significant dose reductions. Limitations of our post hoc analysis include heterogeneity between dex dosing schedules and lack of cytogenetic data for all patients. We could not discern specifically why dex was lowered, and it is possible that dex might have been lowered disproportionately commonly in patients who had achieved early responses and thus independently did better. Regardless, these results strongly suggest that maintaining dex 40 mg weekly for the entirety of NDMM induction may be unnecessary in the modern era. Cooperative efforts to study a planned dex de-escalation protocol (i.e., once no longer needed for symptom management or as a pre-medication) alongside patient-reported outcome assessments of symptom burden are being planned. Funding: NIH/NCI/NCTN grants U10CA180888, U10CA180819, U10CA180821, U10CA180820; and in part by Millennium Pharmaceuticals, Inc. (now part of Takeda Pharmaceutical Company), and by Celgene.

Abstract Immunomodulatory drugs (IMiD) are a backbone therapy for multiple myeloma (MM). Despite their efficacy, most patients develop resistance, and the mechanisms are not fully defined. Here, we show that IMiD responses are directed by IMiD-dependent degradation of IKZF1 and IKZF3 that bind to enhancers necessary to sustain the expression of MYC and other myeloma oncogenes. IMiD treatment universally depleted chromatin-bound IKZF1, but eviction of P300 and BRD4 coactivators only occurred in IMiD-sensitive cells. IKZF1-bound enhancers overlapped other transcription factor binding motifs, including ETV4. Chromatin immunoprecipitation sequencing showed that ETV4 bound to the same enhancers as IKZF1, and ETV4 CRISPR/Cas9-mediated ablation resulted in sensitization of IMiD-resistant MM. ETV4 expression is associated with IMiD resistance in cell lines, poor prognosis in patients, and is upregulated at relapse. These data indicate that ETV4 alleviates IKZF1 and IKZF3 dependency in MM by maintaining oncogenic enhancer activity and identify transcriptional plasticity as a previously unrecognized mechanism of IMiD resistance. Significance: We show that IKZF1-bound enhancers are critical for IMiD efficacy and that the factor ETV4 can bind the same enhancers and substitute for IKZF1 and mediate IMiD resistance by maintaining MYC and other oncogenes. These data implicate transcription factor redundancy as a previously unrecognized mode of IMiD resistance in MM. See related article by Welsh, Barwick, et al., p. 34. See related commentary by Yun and Cleveland, p. 5. This article is featured in Selected Articles from This Issue, p. 4

Abstract Multiple myeloma (MM) is a malignancy that is often driven by MYC and that is sustained by IRF4, which are upregulated by super-enhancers. IKZF1 and IKZF3 bind to super-enhancers and can be degraded using immunomodulatory imide drugs (IMiD). Successful IMiD responses downregulate MYC and IRF4; however, this fails in IMiD-resistant cells. MYC and IRF4 downregulation can also be achieved in IMiD-resistant tumors using inhibitors of BET and EP300 transcriptional coactivator proteins; however, in vivo these drugs have a narrow therapeutic window. By combining IMiDs with EP300 inhibition, we demonstrate greater downregulation of MYC and IRF4, synergistic killing of myeloma in vitro and in vivo, and an increased therapeutic window. Interestingly, this potent combination failed where MYC and IRF4 expression was maintained by high levels of the AP-1 factor BATF. Our results identify an effective drug combination and a previously unrecognized mechanism of IMiD resistance. Significance: These results highlight the dependence of MM on IKZF1-bound super-enhancers, which can be effectively targeted by a potent therapeutic combination pairing IMiD-mediated degradation of IKZF1 and IKZF3 with EP300 inhibition. They also identify AP-1 factors as an unrecognized mechanism of IMiD resistance in MM. See related article by Neri, Barwick, et al., p. 56. See related commentary by Yun and Cleveland, p. 5. This article is featured in Selected Articles from This Issue, p. 4

AbstractDeeper responses are associated with longer survival in multiple myeloma (MM); however, limited data exist on the impact of response kinetics on outcomes. We investigated progression‐free survival (PFS) and duration of response (DOR) by response depth and in early (best confirmed response 0–4 months; n = 424) versus late responders (best confirmed response >4 months; n = 281). Newly diagnosed patients enrolled in TOURMALINE‐MM2 receiving ixazomib‐lenalidomide‐dexamethasone (IRd) (n = 351) or placebo‐Rd (n = 354) were evaluated post hoc. Deeper responses were associated with longer PFS (complete response [CR] not reached [NR], very good partial response [VGPR] 37.2 months, partial response [PR] 16.4 months) and DOR (CR NR, VGPR 42.6 months, PR 15.4 months). Among patients with a PFS (n = 511) or DOR (n = 484) of ≥6 months who achieved ≥PR, median PFS was prolonged among late versus early responders receiving IRd (59.7 vs. 17.9 months) or placebo‐Rd (56.6 vs. 12.4 months), as was median DOR (IRd, NR vs. 20.9 months; placebo‐Rd, 58.2 vs. 11.7 months). While the treatment paradigm for newly diagnosed MM is treatment to progression, our findings suggest slowness of response to a proteasome inhibitor‐immunomodulatory drug‐steroid combination is not a negative predictor of outcome.

Abstract The role of measurable residual disease (MRD) in multiple myeloma patients treated with chimeric antigen receptor (CAR) T cells is uncertain. We analyzed MRD kinetics during the first year after idecabtagene vicleucel (ide-cel) infusion in 125 relapsed/refractory multiple myeloma patients enrolled in KarMMa. At month 1 after ide-cel, there were no differences in progression-free survival (PFS) between patients in less than complete response (CR) versus those in CR; only MRD status was predictive of significantly different PFS at this landmark. In patients with undetectable MRD at 3 months and beyond, PFS was longer in those achieving CR versus <CR. Persistent MRD in the 10−6 logarithmic range and reappearance of normal plasma cells in MRD-negative patients were associated with inferior PFS. This study unveils different prognostic implications of serological and MRD response dynamics after ide-cel and suggests the potential value of studying the reappearance of normal plasma cells as a surrogate of loss of CAR T-cell functionality. Significance: This is one of the first studies evaluating the impact of CR and MRD dynamics after CAR T therapy in relapsed/refractory multiple myeloma. These data help interpret the prognostic significance of serological and MRD responses at early and late time points after CAR T-cell infusion. See related commentary by Landgren and Kazandjian, p. 346 . This article is featured in Selected Articles from This Issue, p. 337

Abstract Introduction: CFT7455 is a highly potent and novel Ikaros Family Zinc Finger Protein 1/3 (IKZF1/3) degrader. In xenograft models, CFT7455 has more potent IKZF1/3 degradation compared to other degraders. Early observations from the FIH clinical trial (NCT04756726) along with supporting translational studies are presented here. Methods: Pre-clinical studies comparing CFT7455 and CC-92480 in both in vitro and xenograft models were performed. The pre-clinical studies’ results coincided with observations from the on-going clinical trial. The clinical trial is an open-label, Phase 1/2, multi-center, FIH study in heavily pretreated relapsed/refractory (R/R) MM and non-Hodgkin’s lymphoma (NHL) patients evaluating safety, tolerability, and PK of CFT7455. Eligible MM patients are R/R to therapy and are not candidates for regimens known to provide clinical benefit. A starting dose of 50 μg QD 21 days on/7 days off (21/7) in 28-day cycles was administered. Results: CFT7455 and CC-92480 showed similar cereblon binding profiles and in vitro IKZF1/3 degradation kinetics, translating into sub-nanomolar GI50 values in proliferation assays across a panel of MM cell lines. In the NCI-H929 xenograft model, 100 μg/kg/day of CFT7455 resulted in durable tumor regressions, while 1000 μg/kg/day of CC-92480 gave tumor stasis. Similar results were seen in a systemic model of MM, MM1.S. Both compounds achieved >95% IKZF3 degradation in tumors 4h post dose. At 48h post dose, CFT7455 was more effective than CC-92480 in maintaining IKZF3 degradation (65% vs. 6% respectively). When levels of CFT7455 and CC-92480 in plasma and tumor were compared, CFT7455 concentrations were > DC80 in tumor 48h post dose, while CC-92480 levels were undetectable in tumor and plasma, demonstrating CFT7455 has longer exposure resulting in sustained IKZF1/3 degradation in pre-clinical models. In cohort A, 5 heavily pre-treated MM patients (pts) received single agent CFT7455. 4 pts have received at least 3 cycles, with 2 pts receiving 5 cycles. Neutropenia (grade 4) was observed in 3/5 pts without coincident fever or infection. Additionally, a 2-4 fold accumulation in plasma CFT7455 exposure at steady state was observed. Early pharmacodynamic (PD) data demonstrates deep persistent degradation of IKZF3 (~100%) and serum free light chain reduction (up to 72%) in response to treatment. Stable disease has been observed in 34 pts, suggesting clinical benefit. Conclusions: While CFT7455 showed clinical benefit at 50 ug with deep target degradation, neutropenia was dose limiting. PK/PD modeling suggests alternative dosing regimens may result in increased tolerability with preserved efficacy, and evaluation of them is underway. Updated results will be presented at the meeting. Citation Format: Sagar Lonial, Shambavi Richard, Jeffrey V Matous, Andrew J. Yee, Urvi Shah, Neha Mehta-Shah, Thomas Martin, Eli Muchtar, Sikander Ailawadhi, Paul G. Richardson, Manisha Bhutani, Samantha Perino, Jason Kirby, Roman V. Agafonov, Prasoon Chaturvedi, Bradley Class, Matthew Schnaderbeck, Michael R. Palmer, Cathleen Gorman, Oliver Schoenborn-Kellenberger, Amanda Hoerres, Stewart L. Fisher, Roy M. Pollock, Adam Crystal, Michelle Mahler, Jesus Bardeja. Pharmacokinetic (PK) profile of a novel IKZF1/3 degrader, CFT7455, enables significant potency advantage over other IKZF1/3 degraders in models of multiple myeloma (MM) and the results of the initial treatment cohort from a first-in-human (FIH) phase 1/2 study of CFT7455 in MM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT186.

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.