Progression-free survival as a surrogate endpoint in myeloma clinical trials: an evolving paradigm.

Measurement of overall survival (OS) remains the gold standard for interpreting the impact of new therapies for multiple myeloma in phase 3 trials. However, as outcomes have improved, it is increasingly challenging to use OS as the primary endpoint if timely approval of novel agents is to be ensured to enable maximum benefit for patients. Surrogate endpoints of OS, such as progression-free survival (PFS) and response to treatment, have contributed to approval decisions by the Food and Drug Administration (FDA) and European Medicines Agency as endpoints demonstrating clinical benefit, and the FDA has recently supported the use of minimal residual disease (MRD) as an accelerated approval endpoint in multiple myeloma. This review aims to address situations in which the use of PFS as a surrogate endpoint warrants careful interpretation especially for specific subgroups of patients and considers ways to ensure that studies can be designed to account for possible discordance between PFS and OS. The utility of subgroup analyses, including the potential for those not pre-specified, to identify target populations for new agents is also discussed.

An open-label, first-in-human, single agent, dose escalation study for the evaluation of safety and efficacy of SAR442085 in patients with relapsed or refractory multiple myeloma.

OBJECTIVES: Cluster of differentiation 38 (CD38) is a key target on multiple myeloma (MM) cells. This multi-centre, Phase 1, single-agent study (NCT04000282) investigated SAR442085, a novel fragment crystallisable (Fc)-modified anti-CD38 monoclonal antibody (mAb), with enhanced affinity towards Fc-gamma receptor on effector cells in patients with relapsed and/or refractory (RR) MM. METHODS: This study comprised two parts: Part-A (dose-escalation involving anti-CD38 mAb pre-treated and naïve patients) and Part-B (dose expansion). Primary endpoints were maximum tolerated dose and recommended Phase 2 dose (RP2D). RESULTS: Thirty-seven heavily pre-treated patients were treated in Part A. Part-B (dose-expansion) was not studied. Seven dose-limiting toxicities were reported at DL3, DL5, DL6, and DL7. RP2D was determined to be 5-7·5 mg/kg. Most common treatment-emergent adverse events were infusion-related reactions in 70·3% (26/37) patients. Grade ≥3 thrombocytopenia was reported in 48·6% (18/37). Overall response rate was 70% in anti-CD38 mAb naïve and 4% in anti-CD38 pre-treated patients, with a median progression-free survival of 7·62 (95%CI: 2·858; not calculable) months and 2·79 (95%CI: 1·150; 4·172) months and, respectively. CONCLUSIONS: The efficacy of SAR442085 was promising in anti-CD38 mAb naïve patients but did not extend to the larger cohort of anti-CD38 mAb pre-treated patients. This observation, along with transient high-grade thrombocytopenia, could potentially limit its clinical use.

Daratumumab in transplant-eligible patients with newly diagnosed multiple myeloma: final analysis of clinically relevant subgroups in GRIFFIN.

The randomized, phase 2 GRIFFIN study (NCT02874742) evaluated daratumumab plus lenalidomide/bortezomib/dexamethasone (D-RVd) in transplant-eligible newly diagnosed multiple myeloma (NDMM). We present final post hoc analyses (median follow-up, 49.6 months) of clinically relevant subgroups, including patients with high-risk cytogenetic abnormalities (HRCAs) per revised definition (del[17p], t[4;14], t[14;16], t[14;20], and/or gain/amp[1q21]). Patients received 4 induction cycles (D-RVd/RVd), high-dose therapy/transplant, 2 consolidation cycles (D-RVd/RVd), and lenalidomide±daratumumab maintenance (≤ 2 years). Minimal residual disease-negativity (10-5) rates were higher for D-RVd versus RVd in patients ≥ 65 years (67.9% vs 17.9%), with HRCAs (54.8% vs 32.4%), and with gain/amp(1q21) (61.8% vs 28.6%). D-RVd showed a trend toward improved progression-free survival versus RVd (hazard ratio [95% confidence interval]) in patients ≥ 65 years (0.29 [0.06-1.48]), with HRCAs (0.38 [0.14-1.01]), and with gain/amp(1q21) (0.42 [0.14-1.27]). In the functional high-risk subgroup (not MRD negative at the end of consolidation), the hazard ratio was 0.82 (0.35-1.89). Among patients ≥ 65 years, grade 3/4 treatment-emergent adverse event (TEAE) rates were higher for D-RVd versus RVd (88.9% vs 77.8%), as were TEAEs leading to discontinuation of ≥ 1 treatment component (37.0% vs 25.9%). One D-RVd patient died due to an unrelated TEAE. These results support the addition of daratumumab to RVd in transplant-eligible patients with high-risk NDMM. Video Abstract.

Multiple myeloma refractory to lenalidomide: A systematic literature review of trials and real-world evidence.

The growing use of frontline lenalidomide treatment in multiple myeloma (MM) is increasing the proportion of lenalidomide-refractory patients, which may limit the efficacy of subsequent lines of treatment (LOT). This systematic literature review (January 2008-October 2023) of clinical trials (CT) and real-world studies (RW) assessed treatment outcomes in adults with relapsed/refractory MM (RRMM) who were previously treated with ≥1 LOT, progressed and were lenalidomide-refractory. Medline, EMBASE and additional electronic databases were searched for articles published in English. Primary outcomes included progression-free survival (PFS), overall survival (OS) and overall/objective response rate (ORR); 24 CT and 19 RW were included. For CT, the population-weighted mean of median PFS (CT = 14) and OS (CT = 6) were shorter in the lenalidomide-refractory cohort (months: 8.8 [n = 2699] and 21.7 [n = 1066], respectively) than the intent-to-treat population (months: 13.8 [n = 5380] and 35.9 [n = 2264], respectively); the population-weighted (N = 2142) mean ORR for lenalidomide-refractory patients (CT = 18) was 56.0%. RW reported considerable variation in PFS (RW = 7), OS (RW = 8) and ORR (RW = 8); and median PFS (RW = 2; months) was lower in lenalidomide/bortezomib-refractory (5.5/5.5; n = 81/n = 25) versus lenalidomide-refractory (7.3/8.0; n = 81/n = 61) patients. These data provide evidence that clinical trials and real-world outcomes are suboptimal in lenalidomide-refractory patients with RRMM, highlighting the need to improve treatment options for this population.

Alliance A061202: Ixazomib, pomalidomide and dexamethasone for lenalidomide-refractory multiple myeloma in first relapse.

Optimal therapy for the growing number of patients with lenalidomide (LEN)-refractory multiple myeloma (MM) in first relapse remains poorly defined. We therefore undertook a randomized phase II study evaluating the efficacy and safety of combining the oral proteasome inhibitor ixazomib (IXA) with pomalidomide (POM) and dexamethasone (DEX) for this patient population. The overall response rate (ORR) for POM-DEX was 43.6% and 63.2% for IXA-POM-DEX. Depth of response, as measured by attainment of a very good partial response or better favored the triplet over the doublet, 28.9% vs 5.1%, respectively (p = 0.0063). A pre-planned interim analysis after 75% of the progression events had occurred demonstrated a progression-free survival (PFS) advantage favoring IXA-POM-DEX that crossed the predefined boundary of superiority, leading to release of the study results. With additional follow-up, the median PFS for POM-DEX was 7.5 months (95% confidence interval [CI] 4.8 - 13.6 months) vs 20.3 months for IXA-POM-DEX (95% CI 7.7 - 26.0 months, hazard ratio 0.437 [upper 90% bound = 0.657]). ORR and median PFS for the 26 of 30 eligible patients who crossed over from the doublet to the triplet at progression was 23.1% and 5.6 months, respectively. Overall survival was similar between the two groups. More hematologic toxicities were seen with the triplet, but non-hematologic adverse events were similar between the two arms. Our data support further testing of this all-oral triplet vs current standard triplet therapy in the context of phase III studies for patients with LEN-refractory disease in first relapse. This trial is registered at www.clinicaltrials.gov as NCT02004275.

Targeting Ikaros and Aiolos: reviewing novel protein degraders for the treatment of multiple myeloma, with a focus on iberdomide and mezigdomide.

INTRODUCTION: The treatment of multiple myeloma (MM) is evolving rapidly. Quadruplet regimens incorporating proteasome inhibitors, immunomodulatory drugs (IMiDs), and CD38 monoclonal antibodies have emerged as standard-of-care options for newly diagnosed MM, and numerous novel therapies have been approved for relapsed/refractory MM. However, there remains a need for novel options in multiple settings, including refractoriness to frontline standards of care. AREAS COVERED: Targeting degradation of IKZF1 and IKZF3 - Ikaros and Aiolos - through modulation of cereblon, an E3 ligase substrate recruiter/receptor, is a key mechanism of action of the IMiDs and the CELMoD agents. Two CELMoD agents, iberdomide and mezigdomide, have demonstrated substantial preclinical and clinical activity in MM and have entered phase 3 investigation. Using a literature search methodology comprising searches of PubMed (unlimited time-frame) and international hematology/oncology conference abstracts (2019-2023), this paper reviews the importance of Ikaros and Aiolos in MM, the mechanism of action of the IMiDs and CELMoD agents and their relative potency for targeting Ikaros and Aiolos, and preclinical and clinical data on iberdomide and mezigdomide. EXPERT OPINION: Emerging data suggest that iberdomide and mezigdomide have promising activity, including in IMiD-resistant settings and, pending phase 3 findings, may provide additional treatment options for patients with MM.

Endothelial injury and dysfunction with emerging immunotherapies in multiple myeloma, the impact of COVID-19, and endothelial protection with a focus on the evolving role of defibrotide.

Patients with multiple myeloma (MM) were among the groups impacted more severely by the COVID-19 pandemic, with higher rates of severe disease and COVID-19-related mortality. MM and COVID-19, plus post-acute sequelae of SARS-CoV-2 infection, are associated with endothelial dysfunction and injury, with overlapping inflammatory pathways and coagulopathies. Existing treatment options for MM, notably high-dose therapy with autologous stem cell transplantation and novel chimeric antigen receptor (CAR) T-cell therapies and bispecific T-cell engaging antibodies, are also associated with endothelial cell injury and mechanism-related toxicities. These pathologies include cytokine release syndrome (CRS) and neurotoxicity that may be exacerbated by underlying endotheliopathies. In the context of these overlapping risks, prophylaxis and treatment approaches mitigating the inflammatory and pro-coagulant effects of endothelial injury are important considerations for patient management, including cytokine receptor antagonists, thromboprophylaxis with low-molecular-weight heparin and direct oral anticoagulants, and direct endothelial protection with defibrotide in the appropriate clinical settings.

Use of defibrotide in COVID-19 pneumonia: comparison of a phase II study and a matched real-world cohort control.

The coronavirus disease 2019 (COVID-19) pandemic led to an unprecedented burden on healthcare systems around the world and a severe global socioeconomic crisis, with more than 750 million confirmed cases and at least 7 million deaths reported by 31st December 2023. The DEFI-VID19 study (ClinicalTrials.gov NCT04335201), a phase II, single-arm, multicenter, open-label trial was designed in mid-2020 to assess the safety and efficacy of defibrotide in treating patients with COVID-19 pneumonia. Defibrotide was administered at a dose of 25 mg/kg/d intravenously, divided into four daily doses over a planned 14-day period for patients with COVID-19 pneumonia receiving non-invasive ventilation. The primary endpoint was Respiratory Failure Free Survival (RFFS); Overall Survival (OS), the number of post-recovery days, and adverse events were the secondary endpoints. For comparison, a contemporaneous control cohort receiving standard of care only was retrospectively selected by applying the eligibility criteria of the DEFI-VID19 trial. To adjust for the imbalance between the two cohorts in terms of baseline variable distributions, an outcome regression analysis was conducted. In adjusted analysis, patients receiving defibrotide reported a trend towards higher RFFS (HR=0.71[0.95CI: 0.34 to 1.29, P= .138]) and OS (HR=0.78[0.95CI: 0.33 to 1.53, P= .248]) and showed a significantly increased number of post-recovery days (difference in means: 3.61[ 0.95CI: 0.97 to 6.26, P= .0037]). Despite concomitant thromboprophylaxis with low molecular weight heparin, the safety profile of defibrotide proved to be favorable. Taken together, our findings suggest that defibrotide may represent a valuable addition to the COVID-19 therapeutic options.

Long-Term Follow-Up Defines the Population That Benefits from Early Interception in a High-Risk Smoldering Multiple Myeloma Clinical Trial Using the Combination of Ixazomib, Lenalidomide, and Dexamethasone.

Background: Early therapeutic intervention in high-risk SMM (HR-SMM) has demonstrated benefit in previous studies of lenalidomide with or without dexamethasone. Triplets and quadruplet studies have been examined in this same population. However, to date, none of these studies examined the impact of depth of response on long-term outcomes of participants treated with lenalidomide-based therapy, and whether the use of the 20/2/20 model or the addition of genomic alterations can further define the population that would benefit the most from early therapeutic intervention. Here, we present the results of the phase II study of the combination of ixazomib, lenalidomide, and dexamethasone in patients with HR-SMM with long-term follow-up and baseline single-cell tumor and immune sequencing that help refine the population to be treated for early intervention studies. Methods: This is a phase II trial of ixazomib, lenalidomide, and dexamethasone (IRD) in HR-SMM. Patients received 9 cycles of induction therapy with ixazomib 4mg on days 1, 8, and 15; lenalidomide 25mg on days 1-21; and dexamethasone 40mg on days 1, 8, 15, and 22. The induction phase was followed by maintenance with ixazomib 4mg on days 1, 8, and 15; and lenalidomide 15mg d1-21 for 15 cycles for 24 months of treatment. The primary endpoint was progression-free survival after 2 years of therapy. Secondary endpoints included depth of response, biochemical progression, and correlative studies included single-cell RNA sequencing and/or whole-genome sequencing of the tumor and single-cell sequencing of immune cells at baseline. Results: Fifty-five patients, with a median age of 64, were enrolled in the study. The overall response rate was 93%, with 31% of patients achieving a complete response and 45% achieving a very good partial response or better. The most common grade 3 or greater treatment-related hematologic toxicities were neutropenia (16 patients; 29%), leukopenia (10 patients; 18%), lymphocytopenia (8 patients; 15%), and thrombocytopenia (4 patients; 7%). Non-hematologic grade 3 or greater toxicities included hypophosphatemia (7 patients; 13%), rash (5 patients; 9%), and hypokalemia (4 patients; 7%). After a median follow-up of 50 months, the median progression-free survival (PFS) was 48.6 months (95% CI: 39.9 - not reached; NR) and median overall survival has not been reached. Patients achieving VGPR or better had a significantly better progression-free survival (p<0.001) compared to those who did not achieve VGPR (median PFS 58.2 months vs. 31.3 months). Biochemical progression preceded or was concurrent with the development of SLiM-CRAB criteria in eight patients during follow-up, indicating that biochemical progression is a meaningful endpoint that correlates with the development of end-organ damage. High-risk 20/2/20 participants had the worst PFS compared to low- and intermediate-risk participants. The use of whole genome or single-cell sequencing of tumor cells identified high-risk aberrations that were not identified by FISH alone and aided in the identification of participants at risk of progression. scRNA-seq analysis revealed a positive correlation between MHC class I expression and response to proteasome inhibition and at the same time a decreased proportion of GZMB+ T cells within the clonally expanded CD8+ T cell population correlated with suboptimal response. Conclusions: Ixazomib, lenalidomide and dexamethasone in HR-SMM demonstrates significant clinical activity with an overall favorable safety profile. Achievement of VGPR or greater led to significant improvement in time to progression, suggesting that achieving deep response is beneficial in HR-SMM. Biochemical progression correlates with end-organ damage. Patients with high-risk FISH and lack of deep response had poor outcomes. ClinicalTrials.gov identifier: (NCT02916771).

Impact of prior treatment on selinexor, bortezomib, dexamethasone outcomes in patients with relapsed/refractory multiple myeloma: Extended follow-up subgroup analysis of the BOSTON trial.

OBJECTIVES: To analyze the impact of prior therapies on outcomes with selinexor, bortezomib, and dexamethasone (SVd) versus bortezomib and dexamethasone (Vd) in 402 patients with relapsed/refractory multiple myeloma (RRMM) in the phase 3 BOSTON trial. METHODS: Post hoc analysis of progression-free survival (PFS), overall survival (OS), and safety for lenalidomide-refractory, proteasome inhibitor (PI)-naïve, bortezomib-naïve, and one prior line of therapy (1LOT) patient subgroups. RESULTS: At a median follow-up of over 28 months, clinically meaningful improvements in PFS were noted across all groups with SVd. The median SVd PFS was longer in all subgroups (lenalidomide-refractory: 10.2 vs. 7.1 months, PI-naïve: 29.5 vs. 9.7; bortezomib-naïve: 29.5 vs. 9.7; 1LOT: 21.0 vs. 10.7; p < .05). The lenalidomide-refractory subgroup had longer OS with SVd (26.7 vs. 18.6 months; HR 0.53; p = .015). In all subgroups, overall response and ≥very good partial response rates were higher with SVd. The manageable safety profile of SVd was similar to the overall patient population. CONCLUSIONS: With over 2 years of follow-up, these clinically meaningful outcomes further support the use of SVd in patients who are lenalidomide-refractory, PI-naïve, bortezomib-naïve, or who received 1LOT (including a monoclonal antibody) and underscore the observed synergy between selinexor and bortezomib.

Daratumumab-based quadruplet therapy for transplant-eligible newly diagnosed multiple myeloma with high cytogenetic risk.

In the MASTER study (NCT03224507), daratumumab+carfilzomib/lenalidomide/dexamethasone (D-KRd) demonstrated promising efficacy in transplant-eligible newly diagnosed multiple myeloma (NDMM). In GRIFFIN (NCT02874742), daratumumab+lenalidomide/bortezomib/dexamethasone (D-RVd) improved outcomes for transplant-eligible NDMM. Here, we present a post hoc analysis of patients with high-risk cytogenetic abnormalities (HRCAs; del[17p], t[4;14], t[14;16], t[14;20], or gain/amp[1q21]). Among 123 D-KRd patients, 43.1%, 37.4%, and 19.5% had 0, 1, or ≥2 HRCAs. Among 120 D-RVd patients, 55.8%, 28.3%, and 10.8% had 0, 1, or ≥2 HRCAs. Rates of complete response or better (best on study) for 0, 1, or ≥2 HRCAs were 90.6%, 89.1%, and 70.8% for D-KRd, and 90.9%, 78.8%, and 61.5% for D-RVd. At median follow-up (MASTER, 31.1 months; GRIFFIN, 49.6 months for randomized patients/59.5 months for safety run-in patients), MRD-negativity rates as assessed by next-generation sequencing (10-5) were 80.0%, 86.4%, and 83.3% for 0, 1, or ≥2 HRCAs for D-KRd, and 76.1%, 55.9%, and 61.5% for D-RVd. PFS was similar between studies and superior for 0 or 1 versus ≥2 HRCAs: 36-month PFS rates for D-KRd were 89.9%, 86.2%, and 52.4%, and 96.7%, 90.5%, and 53.5% for D-RVd. These data support the use of daratumumab-containing regimens for transplant-eligible NDMM with HCRAs; however, additional strategies are needed for ultra-high-risk disease (≥2 HRCAs). Video Abstract.

Health-related quality of life in transplant-eligible patients with newly diagnosed multiple myeloma treated with daratumumab, lenalidomide, bortezomib, and dexamethasone: Patient-reported outcomes from GRIFFIN.

In the phase 2 GRIFFIN trial (ClinicalTrials.gov identifier: NCT02874742), daratumumab added to lenalidomide, bortezomib, and dexamethasone (D-RVd) improved depth of response and progression-free survival (PFS) versus lenalidomide, bortezomib, and dexamethasone (RVd) alone in transplant-eligible (TE) patients with newly diagnosed multiple myeloma (NDMM). Here, we present patient-reported outcomes (PROs) collected using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30-item (QLQ-C30), EORTC Quality of Life Questionnaire Multiple Myeloma Module 20-item (QLQ-MY20), and EuroQol 5-Dimension 5-Level (EQ-5D-5L) tools on day 1 of cycles 1, 2, and 3; on day 21 of cycle 4 (end of induction therapy); on day 1 of cycle 5; on day 21 of cycle 6 (end of posttransplant consolidation therapy); and at months 6, 12, 18, and 24 of maintenance therapy. Meaningful improvements from baseline were seen in most of the PRO scales with both treatments after consolidation and were sustained for at least 2 years of maintenance treatment. Large reductions from baseline (~20 points) were especially observed in pain symptoms for both treatment groups, although these were numerically higher for patients receiving D-RVd during the majority of the time points. In addition, improvements in key scales, such as global health status, fatigue symptoms, and physical functioning, were also seen with both D-RVd and RVd. These improvements in health-related quality of life contribute to the totality of evidence supporting the improvement in clinical outcomes such as response rates and PFS with D-RVd in induction, consolidation, and maintenance therapy in TE patients with NDMM.

Isatuximab, carfilzomib, lenalidomide, and dexamethasone in patients with newly diagnosed, transplantation-eligible multiple myeloma (SKylaRk): a single-arm, phase 2 trial.

BACKGROUND: Isatuximab is a CD38 monoclonal antibody approved for relapsed or refractory multiple myeloma. We aimed to evaluate the addition of isatuximab to weekly carfilzomib (K), lenalidomide (R), and dexamethasone (d; Isa-KRd) in transplant-eligible patients with newly diagnosed multiple myeloma and stratified maintenance by cytogenetic risk. METHODS: This single-arm phase 2 trial was done at three cancer centres (two hospitals and a cancer institute) in Boston (MA, USA). Eligible patients were aged at least 18 years and had transplant-eligible newly diagnosed multiple myeloma and an ECOG performance status of 2 or less. Patients received four 28-day cycles of Isa-KRd, including isatuximab 10 mg/kg intravenously weekly for 8 weeks, then every other week for 16 weeks, and every 4 weeks thereafter; carfilzomib 56 mg/m2 intravenously on days 1, 8, and 15 (20 mg/m2 for cycle 1 day 1); lenalidomide 25 mg orally on days 1-21; and dexamethasone 20 mg orally the day of and day after all doses of carfilzomib and isatuximab. Consolidation involved either upfront haematopoietic stem-cell transplantation (HSCT) with two additional cycles or deferred HSCT with four additional cycles of treatment. The primary endpoint was complete response after four cycles of treatment. Analyses were by intention-to-treat. All patients who received one dose of study drug were included in the safety analyses. This study was registered at ClinicalTrials.gov, NCT04430894, and has completed enrolment. FINDINGS: Between July 31, 2020 and Jan 31, 2022, 50 patients were enrolled. Median age was 59 years (range 40-70), 54% (27 of 50 patients) were male, and 44 (88%) were White. 46% (23 of 50) of patients had high-risk cytogenetics. Median follow-up was 26 months (IQR 20·7-30·1). 32% (16 of 50 patients) achieved a complete response after four cycles. The overall response rate (ORR) was 90% (45 patients) and 78% (39 patients) achieved a very good partial response (VGPR) or better. After completion of consolidation, 58% (29 patients) achieved a complete response; the ORR was 90% (45 patients) and 86% (43 patients) achieved a VGPR or better. The most common grade 3 or 4 side-effects (≥two patients) included neutropenia (13 [26%] of 50 patients), elevated alanine aminotransferase (six [12%] patients), fatigue (three [6%] patients), thrombocytopenia (three [6%] patients), acute kidney injury (two [4%] patients), anaemia (two [4%] patients), and febrile neutropenia (two [4%] patients). Grade 1-2 infusion-related reactions were seen in 20% (ten patients), with none grade 3. Grade 1-2 hypertension was seen in 14% (seven patients) with one grade 3 (one [2%] patient). There were two deaths assessed as unrelated to treatment. INTERPRETATION: Although the study did not achieve the prespecified complete response threshold, Isa-KRd induced deep and durable responses in transplant-eligible patients with newly diagnosed multiple myeloma. The treatment proved safe and consistent with similar regimens in this setting. FUNDING: Amgen, Sanofi, and Adaptive.

Mezigdomide-A Novel Cereblon E3 Ligase Modulator under Investigation in Relapsed/Refractory Multiple Myeloma.

Mezigomide is an oral cereblon E3 ligase modulator (CELMoD) that is under clinical investigation in patients with relapsed/refractory (RR) multiple myeloma (MM). Like other CELMoD compounds, mezigdomide acts by altering the conformation of cereblon within the cullin 4A ring ligase-cereblon (CRL4CRBN) E3 ubiquitin ligase complex, thereby recruiting novel protein substrates for selective proteasomal degradation. These include two critical lymphoid transcription factors, Ikaros family zinc finger proteins 1 and 3 (IKZF1 and IKZF3), also known as Ikaros and Aiolos, which have important roles in the development and differentiation of hematopoietic cells, in MM pathobiology, and in suppressing the expression of interferon-stimulating genes and T-cell stimulation. Among the CELMoDs, mezigdomide has the greatest cereblon-binding potency, plus the greatest potency for the degradation of Ikaros and Aiolos and subsequent downstream antimyeloma effects. Preclinical studies of mezigdomide have demonstrated its anti-proliferative and apoptotic effects in MM, along with its immune-stimulatory effects and its synergistic activity with other antimyeloma agents, including in lenalidomide-/pomalidomide-resistant MM cell lines and mouse xenograft models. Early-phase clinical trial data indicate notable activity in heavily pretreated patients with RRMM, including those with triple-class-refractory disease, together with a tolerable and manageable safety profile. This review summarizes current preclinical and clinical findings with mezigdomide and its potential future roles in the treatment of MM.

Loss of GABARAP mediates resistance to immunogenic chemotherapy in multiple myeloma.

ABSTRACT: Immunogenic cell death (ICD) is a form of cell death by which cancer treatments can induce a clinically relevant antitumor immune response in a broad range of cancers. In multiple myeloma (MM), the proteasome inhibitor bortezomib is an ICD inducer and creates durable therapeutic responses in patients. However, eventual relapse and resistance to bortezomib appear inevitable. Here, by integrating patient transcriptomic data with an analysis of calreticulin (CRT) protein interactors, we found that GABA type A receptor-associated protein (GABARAP) is a key player whose loss prevented tumor cell death from being perceived as immunogenic after bortezomib treatment. GABARAP is located on chromosome 17p, which is commonly deleted in patients with high risk MM. GABARAP deletion impaired the exposure of the eat-me signal CRT on the surface of dying MM cells in vitro and in vivo, thus reducing tumor cell phagocytosis by dendritic cells and the subsequent antitumor T-cell response. Low GABARAP was independently associated with shorter survival in patients with MM and reduced tumor immune infiltration. Mechanistically, we found that GABARAP deletion blocked ICD signaling by decreasing autophagy and altering Golgi apparatus morphology, with consequent defects in the downstream vesicular transport of CRT. Conversely, upregulating autophagy using rapamycin restored Golgi morphology, CRT exposure, and ICD signaling in GABARAPKO cells undergoing bortezomib treatment. Therefore, coupling an ICD inducer, such as bortezomib, with an autophagy inducer, such as rapamycin, may improve patient outcomes in MM, in which low GABARAP in the form of del(17p) is common and leads to worse outcomes.

Post hoc analysis of daratumumab plus lenalidomide, bortezomib and dexamethasone in Black patients from final data of the GRIFFIN study.

Due in part to racial disparities and underrepresentation in clinical studies, optimal therapies for Black patients with multiple myeloma remain undefined. This final analysis of GRIFFIN by race showed that the addition of daratumumab (D) to lenalidomide/bortezomib/dexamethasone (RVd) provides clinical benefit among both Black and White transplant-eligible newly diagnosed patients compared with RVd alone. However, Black patients were more likely to discontinue ≥1 drug due to treatment-emergent adverse events. In summary, these findings suggest a benefit of D-RVd front-line therapy among Black and White patients and underscore the importance of equitable treatment access for all patients.

Adjusting for subsequent therapies in the TOURMALINE-MM1 study shows clinically meaningful improvement in overall survival with addition of ixazomib to lenalidomide and dexamethasone.

TOURMALINE-MM1, the only blinded randomized study in patients with relapsed and/or refractory multiple myeloma (RRMM; ≥1 prior therapy) in the last 10 years, investigated ixazomib + lenalidomide + dexamethasone (IRd) versus lenalidomide + dexamethasone (Rd). Final overall survival (OS) data were based on a median follow-up of 85 months. In RRMM trials where patients have had 1-3 relapses after initial treatment, a high proportion receive subsequent therapy. Application of salvage therapies in blinded trials and newer modes of therapy can increasingly complicate the interpretation of OS. This analysis explores the impact of subsequent therapies on OS outcomes in TOURMALINE-MM1. The inverse probability of censoring weights (IPCW) method, marginal structural model (MSM), and rank-preserving structural failure time model (RPSFTM) were utilized to adjust for confounding on OS, introduced by subsequent therapies. Analyses were conducted for the intent-totreat (ITT) population and ≥2 prior lines subgroup. Unadjusted hazard ratio (HR) for IRd versus Rd was 0.94 (95% confidence interval [CI]: 0.78-1.13) in the ITT population. After adjusting for the impact of subsequent therapies by the RPSFTM method, estimated HR for IRd versus Rd in the ITT population was 0.89 (95% CI: 0.74-1.07). Adjusting with IPCW and MSM methods also showed an improvement in HR, favoring IRd. IRd may be particularly beneficial in patients with ≥2 prior lines of therapy (IPCW and MSM HR=0.52, 95% CI: 0.30-0.88; RPSFTM HR=0.68, 95% CI: 0.51-0.91). These analyses highlight the growing challenge of demonstrating OS benefit in MM patients and the importance of assessing confounding introduced by subsequent therapies when interpreting OS.