Callander, Natalie S.

Background/Objectives: Patients with relapsed/refractory multiple myeloma (RRMM) have poor survival outcomes and limited treatment options. The increasing utilization of multiagent therapies for earlier lines of treatment and novel drug classes including BCMA-targeting agents in subsequent lines of therapy has created a need for innovative treatment platforms in patients who have relapsed after or are refractory to these current standard-of-care approaches. Iopofosine I 131 is a 131iodide (131I)–phospholipid conjugate that exploits the selective uptake and retention of phospholipid ethers through lipid rafts to facilitate tumor delivery of 131I. Methods: The objective of this phase 1 dose-escalation study was to assess the safety and tolerability of single and fractionated dose schedules of iopofosine I 131 + low-dose dexamethasone in heavily pretreated patients with RRMM. Results: The most common AEs overall were cytopenias, notably thrombocytopenia (93.5%), lymphopenia (74.2%), anemia (71%), leukopenia (61.3%), and neutropenia (58.1%). All patients experiencing hematologic adverse events recovered from those events with median time of recovery 21 days post-nadir. Nonhematologic adverse events were mostly limited to Grade 1 and 2. Dose-limiting toxicities included four Grade 4 thrombocytopenia events lasting longer than 7 days, one Grade 4 neutropenia, and one Grade 3 insomnia. The DMC determined 31.25 mCi/m2 was the maximum tolerated dose in the single-dose group, and 20 mCi/m2 × 2 doses was the maximum tolerated dose in the fractionated-dose group. For patients monitored through 85 days following the first infusion, 22 of 26 (84.6%) achieved stable disease after treatment, and 4 of 26 (15.4%) achieved a partial response. Conclusions: A favorable safety and tolerability profile and preliminary clinical activity support further development of iopofosine I 131 in RRMM.

Extramedullary presentations of multiple myeloma (MM) involving the central nervous system (CNS) carry a dismal prognosis. Although historically rare, management of extramedullary disease—including CNS manifestations—has become increasingly clinically relevant as advances in systemic therapies have prolonged control of medullary disease. CNS manifestations may occur across a variety of clinical settings and at different time points throughout the disease course. Common symptoms include visual changes, headaches, loss of sensation, confusion, and seizures. MRI identifies leptomeningeal enhancement and/or parenchymal lesions in approximately 90% of cases, and lumbar puncture with cerebrospinal fluid testing for clonal plasma cell populations is confirmatory. Encouragingly, the incorporation of novel therapeutic agents has improved historically poor outcomes in CNS MM. Novel immunotherapeutic approaches using CAR T-cell therapy and bispecific T-cell–engaging antibodies have recently demonstrated significant efficacy in consolidating responses. Multimodality treatment strategies incorporating intrathecal chemotherapy, systemic novel agents, radiation therapy, and immunotherapy hold promise for achieving more durable responses in this devastating manifestation of MM.

The treatment landscape for multiple myeloma (MM) is evolving rapidly and includes several new options. The management must be tailored to the individual. The NCCN Guidelines for MM provide a framework to base decisions regarding diagnosis, workup, treatment, and follow-up of both newly diagnosed and previously treated relapsed/refractory MM. This manuscript outlines the recommendations from NCCN Guidelines for MM specific to newly diagnosed MM (NDMM).

7540 Background: The combination of a proteasome inhibitor (PI) with lenalidomide (R) and dex (d) has been a common initial therapy for newly diagnosed myeloma (NDMM). We designed a randomized phase 3 trial to examine if carfilzomib (K), a next generation PI, improved progression free survival (PFS) compared with bortezomib (V) when either is combined with Rd for initial treatment of NDMM. Initial analysis at a median follow up of 15.3 months (mos) showed comparable PFS for both triplets. We present the long-term results of the trial with ~70 months median follow up. Methods: Patients (Pts) with NDMM, were randomized 1:1 to receive VRd or KRd for 36 weeks followed by a 2 nd randomization (1:1) to indefinite versus 2 yrs of R maintenance. Pts without del17p, t(14;16), t(14;20), plasma cell leukemia or high-risk GEP70 profile, were enrolled. VRd arm included V 1.3 mg/m 2 on days(d) 1, 4, 8, and 11 (d1, 8 for cycles 9-12), R 25 mg d1-14, and d 20 mg d1, 2, 4, 5, 8, 9, 11, 12 of a 3-week (wk) cycle for 12 cycles, while pts in the KRd arm received K 36 mg/m 2 d1, 2, 8, 9, 15, 16 with R 25 mg daily on d1-21 and d 40 mg wkly, in 4 wk cycles for 9 cycles. Maintenance used 15 mg R d1-21 q4 wks. Results: The study accrued 1087 pts (VRd=542, KRd=545). Median age was 65y; baseline characteristics including intent to transplant were similar across the arms. Median induction duration (mos; IQR) was 7.2 (3.4-8.9) and 8.4 (5.1-9.1) for VRd and KRd, respectively; 59.8% in VRd and 45.3% in KRd did not proceed to Step 2. Median PFS (mos) was VRd=41.9 and KRd=44.6; HR = 0.89 (0.76-1.04). Toxicity data, PFS sensitivity analyses and OS probabilities are as in the table. Conclusions: In this randomized trial, with median follow up of nearly 6 years, KRd and VRd had comparable PFS and OS in an intent to treat analysis. While similar numbers proceeded to SCT in the 2 arms, more did so during induction in the VRd arm while more patients in the KRd arm went to SCT later. VRd remains a standard triplet induction regimen in standard and intermediate risk NDMM, and a suitable backbone for 4 drug combinations. Clinical trial information: NCT01863550 . N (%) VRd(n=527) KRd(n=526) SCT anytime 186 (34.3) 183 (33.6) SCT without Step 2 registration 146 112 Median Time to SCT (mos; range) 7.7 (3.5-83.9) 10.6 (3.7-70.6) Grade 3-4 Treatment-Related Toxicity 315 (59.8) 344 (65.4) Grade 5 Treatment-Related Toxicity 2 (0.4) 9 (1.7) Grade 5 All Events 11 (2.1) 20 (3.8) Survival outcomes HR Median (95% CI) Median (95% CI) PFS Primary: PD or death within 3 months of last evaluation as events 0.89(0.76-1.04) 41.9(35.7, 50.3) 44.6(38.2, 51.9) PFS Sensitivity: All deaths as events, 0.87(0.75-1.02) 39.5(34.9, 46.0) 42.8(37.4, 49.7) PFS Sensitivity: Censor at alternate Rx 0.83(0.69-0.99) 35.0(31.3, 42.6) 38.7(34.7, 49.0) PFS Sensitivity: Event at alternate Rx 0.84(0.73-0.97) 18.0(14.2, 23.0) 24.4(20.9, 27.9) Overall survival 0.92(0.75-1.12) 119(100, NE) 118(103-NE)

The NCCN Guidelines for Multiple Myeloma (MM) provide recommendations for diagnosis, initial workup, treatment, follow-up, and supportive care for patients with MM. These NCCN Guidelines Insights highlight the important updates and changes specific to systemic therapy for patients with newly diagnosed as well as previously treated MM included in Version 1.2025 of the NCCN Guidelines for MM.

Background The International Myeloma Working Group (IMWG) defines progression of disease (PD) in multiple myeloma by the increase in serum or urine paraprotein beyond a certain threshold. With more common use of serial bone marrow-based measurable residual disease (MRD) assessment, some patients will evolve with increase in MRD burden without meeting IMWG criteria for PD and no consensus exist on the best approach for this circumstance. Understanding the implication of increasing MRD burden is particularly relevant in patients with NDMM treated with quadruplet therapy (QUAD, consisting of a PI, an IMiD, an anti-CD38 mAb and dexamethasone) and autologous stem cell transplantation (ASCT), since most will reach MRD negativity. Methods We analyzed a large dataset of patients with NDMM patients treated with QUADs + ASCT +/- QUAD consolidation +/- single or dual-agent maintenance and monitored with serial MRD assessment by next-generation sequencing (clonoSEQ®) at end of induction, post ASCT, post consolidation and at least yearly thereafter. The dataset was built from clinical trial participants and from patients receiving standard care under an institutional guideline. MRD progression (MRD-P) was arbitrarily defined as quantitative increase in MRD burden by at least 1 log10 above the nadir. Treatment modification in the event of MRD-P without IMWG-defined PD was at discretion of treating physician. For patients with MRD-P without concomitant PD we describe cumulative incidence of PD after MRD-P. To contextualize the clinical implications of MRD-P, we describe survival free of failure of second line therapy (SFF2T), defined as time from progression event (MRD-P or PD not preceded by MRD-P) until occurrence of IMWG-defined PD or death on second line therapy, regardless of whether second line was initiated due to MRD-P or subsequent IMWG-defined PD. Results Among the 216 patients, 113 (52%) were clinical trial participants, median age was 61 years (IQR 56-68), 21% age 70 or older, 32% were non-White, 57% male, 38% had MM with 1 high risk chromosome abnormality [HRCA, gain/amp 1q, t(4;14), t(14:16), del(17p)], 15% had 2+HRCA. Median duration of follow up is 39.5 months, and 966 MRD datapoints were assessed. Overall, 83% of patients achieved sCR, 78% achieved MRD negativity at 10-5, 68% at the 10-6 threshold, and 56% ceased therapy after confirmed MRD negativity. Forty-nine patients had MRD-P(N=19) or PD not preceded by MRD-P (N=30). Patients with MRD-P or PD not preceded by MRD-P often had 1 or more HRCA (73.7% and 82.8%), International staging system III (36.8% and 30.0%), and high LDH at diagnosis (31.6% and 23.3%). Median time from onset of therapy to MRD-P was 24.4 mo (IQR 12.6-35.8) and to PD not preceded by MRD-P was 23.2 mo (IQR 18.4-29.4). Among the 19 patients with MRD-P, 12 (63%) were on observation at time of MRD-P, 2 were receiving single agent lenalidomide, 5 were receiving a QUAD, 17 (89%) had previously obtained MRD negativity at <10-5 including 10 (53%) who had also achieved MRD negativity at 10-6. Upon detection of MRD-P, 12 (63%) pts changed therapy, all to a monoclonal antibody-containing triplet or quadruplet regimen. Yet, median time from MRD-P to PD was 10.1 months. Patients with MRD-P had 1-year SFF2T of 55.6%, in contrast to 35.0% for patients with PD not preceded by MRD-P. OS 2-year from progression event was 78.0% for MRD-P and 53.9% for PD not preceded by MRD-P. Conclusions In the context of NDMM treated with QUAD + ASCT, MRD-P indicates imminent IMWG-defined PD, and is driven by a thriving plasma cell population unlikely to be controlled by reinstitution of anti-CD38 mAb-based combinations. Outcomes of patients with MRD-P are similar to those of patients with IMWG-defined PD. These findings challenge the paradigm of IMWG-defined PD and paraprotein measurability as minimal parameters for change in therapy and introduction of agents with new mechanisms of action.

Introduction QUADs with an anti-CD38 mAb, an IMiD, a proteasome inhibitor and dexamethasone followed by autologous stem cell transplantation (ASCT) in the treatment of newly diagnosed multiple myeloma (NDMM) led to substantial improvements in depth of response, including minimal residual disease (MRD) negativity, and progression-free survival. The therapeutic success of QUAD + ASCT has reinvigorated an interest in fixed-duration therapy, yet optimal short term efficacy endpoint for treatment cessation is unknown. We used a large dataset of patients (pts) treated with QUAD + ASCT, monitored with serial MRD assessment and managed with MRD-adapted treatment duration to determine the best short term efficacy endpoint to identify pts at low risk of treatment failure. Methods We analyzed 221 pts with NDMM treated with QUAD + ASCT and monitored with serial marrow-based MRD by next-generation sequencing. Based on trial design (N=116) and institutional practice (N=105) most pts received post ASCT QUAD consolidation followed by treatment cessation if MRD<10-5 in two consecutive datapoints. Pts were monitored with MRD post induction, ASCT and consolidation, and at least yearly thereafter. We utilized Cox regression to build parallel models of predictors of disease progression or MRD resurgence utilizing the same patient and disease features and one distinct short term efficacy endpoint per model, inputted as time-varying covariate. Efficacy endpoints tested were IMWG-defined stringent complete response (sCR), MRD<10-5 (single datapoint), MRD<10-6, sustained MRD (S-MRD, two consecutive assessments at least 1 year apart) <10-5and S-MRD<10-6. Best fitting models were determined using Akaike's information criterion (AIC, lower value indicates better fitting model), an information theory approach, and Heagerty & Zheng C index. Results Median age of the 221 pts. was 61 years (IQR 55-68), 21% age 70 or older, 37% had MM with 1 high risk chromosome abnormality [HRCA, gain/amp 1q, t(4;14), t(14:16), del(17p)], 16% had 2+HRCA, 30% were non-White and 58% male. We followed pts for a median of 40.6 mo. and performed 979 MRD assessments. One hundred and eighty-three pts (83%) achieved sCR, 170(77%) MRD<10-5, 146 (66%) MRD<10-6 , 110 (50%) S-MRD<10-5 and 90 (41%) S-MRD<10-6. Average time to achieve the endpoint was 7.8 mo for sCR, 7.1 mo. for MRD <10-5, 9.4 mo. for MRD<10-6, 19.3 mo. for S-MRD<10-5 and 20.5 mo. for S-MRD<10-6. We first tested models to predict PFS among all 221 pts. Predictive models included same covariates (ISS, high LDH and number of HRCA) other than the efficacy endpoint. The best fitting model (AIC 417.2, C-stat 0.757) was based on S-MRD<10-5 (HR=0.23, 95% C.I. 0.11-0.47) and included presence of 1 HRCA (HR=2.93, 95% C.I. 1.31-6.52), 2+ HRCA (HR=7.60, 95% C.I. 3.31-17.43), high LDH (HR=1.64, 95% C.I. 0.81-3.33), ISS2 (HR 1.31, 95% C.I. 0.62-2.77) and ISS3 (HR 1.96, 95% C.I. 0.90-4.28). The model with S-MRD<10-6 had similar, but not better performance (AIC 419.4, C-stats 0.752). We subsequently analyzed the 121 (55%) pts who reached MRD-guided treatment cessation for the best fitting model to predict progression or MRD resurgence in absence of continuous therapy. Among these pts, 117(97%) achieved sCR, all (by definition) MRD<10-5, 116 (96%) MRD<10-6 , 95 (79%) S-MRD<10-5 and 81 (67%) S-MRD<10-6. The best fitting model (AIC 197.2, C-stat 0.766) was based on S-MRD<10-5 (HR 0.01, 95% C.I. 0.002-0.05) and included presence of 1 HRCA (HR=1.41, 95% C.I. 0.49-4.07), 2+ HRCA (HR=5.43, 95% C.I. 1.75-16.84), high LDH (HR=3.19, 95% C.I. 0.98-10.40), ISS2 (HR 1.25, 95% C.I. 0.53-2.96) and ISS3 (HR 0.73, 95% C.I. 0.23-2.37). The model with S-MRD<10-6 did not perform better (AIC 232.4, C-stat 0.727). Among the 94 pts who achieved S-MRD<10-5 and were monitored off therapy, the risk of MRD resurgence or progression 2.5 years after cessation of therapy was 6.1%, 15.0% and 22.2% and risk of progression was 3.0 %, 12.0% and 11.1% for patients with 0, 1 and 2+ HRCA, respectively Conclusion In the setting of QUAD therapy + ASCT, no short term conventional or MRD-based efficacy parameter negates the cumulative impact of HRCA on prognosis. S-MRD<10-5 is the best predictor of PFS and yields the best predictive models for risk of MRD resurgence or progression in the setting of fixed duration therapy. This analysis validates S-MRD<10-5 as efficacy parameter for treatment cessation in trials exploring fixed duration therapy in NDMM.

Abstract Outcomes are poor in triple-class–exposed (TCE) relapsed and refractory multiple myeloma (R/RMM). In the phase 3 KarMMa-3 trial, patients with TCE R/RMM and 2 to 4 prior regimens were randomized 2:1 to idecabtagene vicleucel (ide-cel) or standard regimens (SRs). An interim analysis (IA) demonstrated significantly longer median progression-free survival (PFS; primary end point; 13.3 vs 4.4 months; P < .0001) and higher overall response rate (ORR) with ide-cel vs SRs. At final PFS analysis (median follow-up, 30.9 months), ide-cel further improved median PFS vs SRs (13.8 vs 4.4 months; hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.38-0.63). PFS benefit with ide-cel vs SRs was observed regardless of number of prior lines of therapy, with greatest benefit after 2 prior lines (16.2 vs 4.8 months, respectively). ORR benefit was maintained with ide-cel vs SRs (71% vs 42%; complete response, 44% vs 5%). Patient-centric design allowed crossover from SRs (56%) to ide-cel upon progressive disease, confounding overall survival (OS) interpretation. At IA of OS, median was 41.4 (95% CI, 30.9 to not reached [NR]) vs 37.9 (95% CI, 23.4 to NR) months with ide-cel and SRs, respectively (HR, 1.01; 95% CI, 0.73-1.40); median OS in both arms was longer than historical data (9-22 months). Two prespecified analyses adjusting for crossover showed OS favoring ide-cel. This trial highlighted the importance of individualized bridging therapy to ensure adequate disease control during ide-cel manufacturing. Ide-cel improved patient-reported outcomes vs SRs. No new safety signals were reported. These results demonstrate the continued favorable benefit-risk profile of ide-cel in early-line and TCE R/RMM. This trial was registered at www.ClinicalTrials.gov as #NCT03651128.