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Introduction: Waldenström macroglobulinemia (WM)remains incurable with current therapies. Treatment options for patients beyond initial therapy are limited, underscoring the need for new agents with novel mechanisms of action. Iopofosine I 131 is a novel radiopharmaceutical composed of a lipid raft-targeting phospholipid ether covalently bound to 131I, a beta-emitting radioisotope. Herein, we report the results of the CLOVER-WaM study [NCT02952508] in patients with previously treated WM. Methods: Eligible WM patients had received >2 prior therapies and had symptomatic disease requiring therapy according to consensus recommendations for WM. Treatment consisted of 2 cycles of iopofosine I 131 administered at 15 mCi/m2 on days 1 and 15 of each 57-day cycle. Dose reduction to 10 mCi/m2 was allowed in the second cycle in patients with incomplete hematologic recovery or if the expected total dose exceeded 132 mCi. Supportive care with growth factors and transfusions was permitted per treating physician discretion. The primary endpoint was major response rate (MRR, defined as partial response or better) as determined by the modified VIth International Workshop on Waldenström Macroglobulinemia Response Criteria. Secondary endpoints included overall response rate (ORR), treatment-free survival (TFS), duration of response (DOR), and clinical benefit rate (CBR, defined as stable disease or better). Efficacy endpoints were assessed in the modified intent-to-treat (mITT) population, defined as all patients who received ≥60 mCi total administered dose of iopofosine I 131. MRR was analyzed with a 95% 2-sided confidence interval (CI) using the Clopper-Pearson interval method. In this population, MRR >20% was considered statistically significant. Time-dependent efficacy endpoints were analyzed using the Kaplan-Meier method. Safety was evaluated using CTCAE v4.03 in patients who received >1 dose of iopofosine I 131. The data cut-off for this analysis was May 31, 2024. Results: In 65 patients enrolled (safety population), the median age was 70 (range, 50-88) years; 48 (73.8%) were male, and 17 (26.2%) were female. Sixty-one (93.8%) were White, 1 (1.5%) was Black/African American, and 3 (4.6%) were other or unknown. Fifty-five patients met mITT criteria and were evaluable for efficacy. The median number of prior therapies was 4 (range, 2-15). Bruton's tyrosine kinase inhibitor (BTKi) exposure was noted in 39 (71%) patients, of whom 31 (56%) were BTKi-refractory. Sixteen (29%) patients had MYD88-wild type, and 5 (9%) had CXCR4-mutated disease. The MRR was 56.4% (95% CI, 42.3-69.7). ORR was 80%; among MYD88-wild type patients, ORR was 81%, and among post-BTKi patients, ORR was 72%. CBR was 98%. The median DOR and TFS were not reached at a median follow-up of 8.8 months, with an estimated 72% of responding patients remaining progression-free at 18 months. In the safety population, any-grade adverse events, regardless of causality, were reported in 57 (87%) patients. Grade 3 or higher treatment-emergent adverse events (TEAEs) occurring in >10% of patients included thrombocytopenia (80%), neutropenia (69.2%), anemia (44.6%), lymphopenia (13.8%), infections (12.3%), and febrile neutropenia (10.8%). Adverse event-related death occurred in 1 patient due to bacterial sepsis. Conclusion: Iopofosine I 131 demonstrated durable efficacy in previously treated WM patients, with no current standard of care therapy. The treatment was well-tolerated with a manageable toxicity profile across broad biologic and clinical subgroups, irrespective of risk stratification. Based on the results of this trial, iopofosine I 131 shows promise as a novel treatment for WM patients.

Abstract Despite the widespread use of carfilzomib (K) in relapsed/refractory multiple myeloma (RRMM), there is no consensus on optimal K dose in milligrams per square meter (mg/m2) or dosing schedule. We assessed three modern K prescribing patterns in RRMM using a large United States electronic health record-derived database. Our final cohort (n = 486) included 136 patients (28.0%) who received K 56 mg/m2 once weekly (K56-1x), 86 (17.7%) who received 56 mg/m2 twice weekly (K56-2x), and 264 (54.3%) who received 70 mg/m2 once weekly (K70-1x). Between 2016 and 2023, once-weekly dosing became more common: K70-1x proportions changed from 21.1% in 2016 to 50.6% in 2023, K56-1x from 15.8% to 37.0%, and K56-2x from 63.2% to 12.3%. Median real-world progression-free survival was 13.0 months [95% confidence interval (CI) 11.2-20.7] for K56-1x, 13.2 months (95% CI 9.0-28.1 months) for K56-2x, and 10.9 months (95% CI 9.9-15.3 months) for K70-1x; these differences were not statistically significant (log-rank p = 0.46). The prevalence of heart failure was comparable (<5% in all cohorts). In summary, our findings do not support improved outcomes with twice-weekly carfilzomib in RRMM. K56-1x may provide the best balance of efficacy, safety, and avoidance of time toxicity from frequent infusions.

The treatment of Waldenström macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) has evolved to include several new options. The NCCN Guidelines for WM/LPL provide a framework on which to base decisions regarding diagnosis, treatment, assessment of response to treatment, and follow-up of both newly diagnosed and previously treated WM/LPL.

AbstractThe presence of a serum immunoglobulin D (IgD) monoclonal protein (M‐protein) is seen in < 1% of patients with monoclonal gammopathies and is usually indicative of a malignant plasma cell disorder. Only a few cases of well‐documented benign monoclonal gammopathy of undetermined significance (MGUS) of IgD subtype have been reported, and only 2 of those had over 5 years of follow‐up at the time they were reported. Herein we describe longer‐term follow‐up of one of those 2 patients who has subsequently passed away from unrelated causes but never developed multiple myeloma or amyloidosis after 26 years of follow‐up. Although IgD MGUS is extremely rare, this case confirms that presence of an IgD M‐Protein is not always synonymous with a malignant plasma cell process.

The treatment of relapsed/refractory multiple myeloma (MM) has evolved to include several new options. These include new combinations with second generation proteasome inhibitors (PI); second generation immunomodulators, monoclonal antibodies, CAR T cells, bispecific antibodies, selinexor, venetoclax, and many others. Most patients with MM undergo several cycles of remissions and relapse, and therefore need multiple lines of combination therapies. Selecting treatment options for relapsed/refractory MM requires consideration of resistance status to specific classes, and patient-specific factors such as age and other comorbidities should be considered. The NCCN Guidelines for MM provide a framework on which to base decisions regarding workup, treatment, and follow-up of newly diagnosed and previously treated MM. This manuscript outlines the recommendations from NCCN Guidelines for MM specific to relapsed/refractory disease.

Introduction In the KarMMa-3 trial (NCT03651128), ide-cel, a BCMA-directed CAR T cell therapy (Tx), significantly improved median progression-free survival (13.3 vs 4.4 mo, HR 0.49, P &lt; 0.001) and overall response rate (71% vs 42%, P &lt; 0.001) vs std regimens in pts with RRMM who were TCE to immunomodulatory (IMiD ®) agents, proteasome inhibitors (PIs), and daratumumab (Rodríguez-Otero NEJM 2023). Early high-grade (gr) cytopenias and severe infections have been reported post-CAR T cell infusion (Logue Blood 2022, Thibaud Blood 2022), and persistent cytopenias and infections can pose clinical challenges in pt care. In this safety analysis of KarMMa-3, we report frequency, kinetics of occurrence, and management of cytopenias and infections post-Tx with ide-cel or std regimens. Methods This international, randomized, multicenter phase 3 trial enrolled pts with RRMM who received 2-4 prior Txs (an IMiD agent, a PI, and daratumumab) and were refractory to the last Tx. Pts were randomized 2:1 to ide-cel or a std regimen (DPd, DVd, IRd, Kd, or EPd) selected by investigator based on prior anti-MM Tx. In the ide-cel arm, pts could have ≤ 1 cycle of optional bridging Tx (BTx) for disease control. Treated population (pop; ide-cel: pts who received leukapheresis [LA], BTx, lymphodepleting chemotherapy, or ide-cel; std regimens: pts who received any dose of study Tx) was used to assess adverse events (AEs), gr 3/4 AEs, and serious AEs. Safety pop (pts who received ide-cel or any dose of std regimens) was used to assess treatment-emergent AEs, AEs of special interest, investigator-identified neurotoxicity/cytokine release syndrome and others. In pts who had documented disease progression on std regimens and then underwent LA to receive ide-cel, only AEs before LA were included. In this analysis, incidence of cytopenias and infections at various time intervals and management, types of infections, and incidence of hypogammaglobulinemia (HGG) were assessed. Results At data cutoff (Oct 3, 2022), median follow-up was 24.1 (range 5.9−41.0) mo in the 386 randomized pts. In the treated pop, 248/249 (99.6%) vs 124/126 (98.4%) pts had any-gr AEs, 234 (94.0%) vs 96 (76.2%) had gr 3/4, and 36 (14.5%) vs 9 (7.1%) had gr 5 in ide-cel vs std regimens arms, respectively. Of the gr 5 AEs, 18/36 and 3/9 had verbatim terms consistent with progressive disease. In the safety pop, incidence of gr 3/4 cytopenias with ide-cel were higher early after infusion but generally resolved over time (196 [87.1%] pts at &lt; 3 mo, 52 [24.1%] pts at 3−&lt; 6 mo, 30 [14.7%] pts at ≥ 6 mo; Table 1) vs std regimens, which showed lower rate of resolution over time. More pts in the ide-cel (16 [7.1%]) vs std regimens arms (3 [2.4%]) had any-gr febrile neutropenia. Cytopenias were mainly managed using colony-stimulating factor in both arms (55.5% and 58.7%, respectively); RBC (48%) and platelet transfusions (32%) were more common in the ide-cel arm. Overall, incidence of gr 3/4 infections was high at &lt; 3 mo and remained consistent over time in both arms (ide-cel: 17 [7.6%] pts at &lt; 3 mo, 18 [8.3%] pts at 3−&lt; 6 mo, 13 [6.4%] pts at ≥ 6 mo; Table 2). Any-gr bacterial infections were more common in the ide-cel vs std regimens arms with higher incidence at &lt; 3 mo (10% vs 6%) but lowered at later timepoints. Incidence of gr ≥ 3 viral infections remained low and consistent with time; fungal infections were uncommon. Deaths due to infections occurred in 3 (1.3%) vs 1 (0.8%) pts at &lt; 3 mo, 0 pts at 3−&lt; 6 mo, and 7 (3.4%) vs 2 (2.6%) pts at ≥ 6 mo in the ide-cel vs std regimens arms, respectively. Indence of any-gr new HGG was higher in the ide-cel vs std regimens arms but decreased over time: 15 (6.7%) vs 2 (1.6%) pts at &lt; 3 mo, 3 (1.4%) vs 1 (0.9%) at 3−&lt; 6 mo, and 5 (2.5%) vs 0 at ≥ 6 mo, respectively; of these, 13 (5.8%) vs 1 (0.8%), 2 (0.9%) vs 1 (0.9%), and 5 (2.5%) vs 0 pts received IV immunoglobulin replacement Tx at the respective time intervals. Incidence rate (% per 100 pt-years, 95% CI) of second primary malignancies remained low and similar between arms (ide-cel, 4.0 [2.4−6.7]; std regimens, 4.4 [1.9−10.7]). Conclusion In KarMMa-3, most severe cytopenias associated with ide-cel occurred early, with a low incidence of prolonged cytopenias; all were largely manageable. Any-gr bacterial infections decreased over time while viral infections remained the same. No new safety concerns were identified for ide-cel; safety profile was consistent with previous reports. Study support 2seventy bio and Celgene, a Bristol-Myers Squibb Company.

Introduction: Most induction regimens for multiple myeloma (MM) contain bortezomib. In most clinical trials, bortezomib has been prescribed either intravenously or subcutaneously twice per week in 21-day or 28-day cycles. However, several retrospective single-center studies have shown that once-weekly bortezomib has comparable efficacy and less peripheral neuropathy compared to twice-weekly bortezomib ( Sidana et al, PLoS One 2017; Cook et al, AJH 2021). These findings have also been confirmed by a secondary analysis of data from three prospective Phase 3 randomized studies ( Mateos et al, Haematologica 2014). As such, many clinicians have adopted once-weekly bortezomib regimens in routine care in the past decade. However, the real-world (RW) prevalence and efficacy of once-weekly vs twice-weekly bortezomib regimens in a larger population have not yet been characterized. Methods: This study used US nationwide longitudinal Flatiron Health electronic health record-derived de-identified data. We included patients aged 18-70 years with newly diagnosed MM between 2017-2022 with ≥ 6 months of follow-up and ≥ 2 clinical visits who were treated with a first-line (1L) bortezomib-containing regimen. Patients aged &gt;70 were excluded a priori given the likelihood of altered practice patterns and more frequent comorbidities. Twice-weekly bortezomib was defined as patients for whom the most frequent interval between two doses of 1L bortezomib within a cycle was 3.0-4.9 days, while once-weekly bortezomib was defined as a corresponding interval of 5.0-9.9 days. We used multivariable logistic regression to assess demographic and clinical factors associated with once-weekly vs twice-weekly (reference) bortezomib. RW progression free survival (rwPFS) and RW overall survival (rwOS) from 1L treatment initiation were estimated using the Kaplan-Meier method. Outcomes were compared using Cox proportional hazards model including transplant as a time-varying covariate and adjustment for other demographic and clinical factors. Results: Of 2,522 patients included, 927 (36.8%) received twice-weekly while 1,522 (63.2%) received once-weekly bortezomib. Approximately half of patients (50.3%) were non-Latinx White, 21.7% non-Latinx Black, and 8.0% Latinx. Most patients were treated in the community setting (78.8%). Rates of once-weekly bortezomib administration were 66.2% and 62.1% among patients treated at academic and community practices, respectively. The frequency of weekly bortezomib use increased over time, from 58.0% between 2017-2019 to 68.8% between 2020-2022. In multivariate analysis, ECOG PS ≥ 2 (odds ratio [OR] 1.50; [95% CI 1.14 to 1.99] vs ECOG PS 0), and more recent year of diagnosis (OR 1.14; [95% CI 1.08 to 1.20] per year) were associated with higher odds of receiving once-weekly bortezomib. Conversely, Latinx patients vs non-Latinx White (OR 0.60 [95% CI 0.44 to 0.82]) and patients with ≥ 2 high-risk cytogenetic abnormalities (HRCA) vs 0 HRCA (OR 0.66 [95% CI 0.48 to 0.91]) had lower odds of receiving once-weekly bortezomib administration. No significant associations were found between gender, ISS stage, practice setting, insurance category, or baseline creatinine. There was no statistically significant difference in rwPFS among patients receiving once-weekly (median 37.3 months, 95% CI 33.8 to 42.5) vs twice-weekly bortezomib (median 39.2 months, 95% CI 32.9 to 42.8) (HR 0.87 [95% CI 0.77 to 1.00]) (Figure 1A). Similarly, there was no statistically significant difference in rwOS with median 25.5 months follow-up (Figure 1B). Median rwOS was not reached in either group (hazard ratio 0.89 [95% CI 0.75 to 1.07]). Discussion: We evaluated US bortezomib prescribing patterns for the first time in the modern era using a large nationwide RW-study. Whereas prescribing patterns have shifted towards once-weekly bortezomib over time, over 30% of patients diagnosed in the last three years received twice-weekly bortezomib. Importantly, once-weekly and twice-weekly bortezomib performed comparably with regard to rwPFS and rwOS. While our study did not analyze neuropathy or patient quality of life, once-weekly bortezomib is known to be associated with less neuropathy and less time in clinic. These data further support the conclusion that once-weekly bortezomib should be considered the standard of care for newly diagnosed patients with MM.

Background: Bortezomib (Velcade), a mainstay of treatment regimens for newly diagnosed multiple myeloma (MM), is often dosed twice-weekly in trials (i.e., Days 1, 4, 8, 11 in 21-day cycles). However, several analyses have shown that once-weekly bortezomib performs comparably and is associated with less peripheral neuropathy (Sidana PLoS One 2017, Mateos L&L 2020, Cook AJH 2021). Many centers thus use once-weekly bortezomib in MM induction regimens regardless of transplant eligibility, e.g. modified VRd or Dara-VRd in 28-day cycles with once-weekly subcutaneous (SC) bortezomib 1.3 mg/m 2 (McCaughan BJH 2022). Physician attitudes and perceptions regarding how bortezomib should be dosed, an important step toward establishing a global standard of care in MM, have not been investigated. Methods: We conducted a global online survey of hematologists/oncologists who had treated ≥1 patient with MM in the past 12 months. The survey was distributed via social media platforms as well as targeted emails to MM physicians, IMWG members, and outreach through professional societies. The survey comprised 14 questions including usage of once- vs twice-weekly bortezomib, usage of SC vs IV bortezomib, attitudinal questions about potential benefits/disadvantages of each approach, and perceived barriers to using once-weekly bortezomib. Statistics were analyzed descriptively with Wilcoxon rank-sum and signed-rank tests. Results: Of 317 webpage visits, 205 responses were recorded (65% completion rate).Most respondents were from US academic practices (25%, n=52), US community practices (22%, n=46), or Australian academic practices (6%, n=13); however, responses were recorded from 38 countries including 22 low- or middle-income countries (LMICs: 29% of responses, n=60).Over a third of respondents (37%, n=76) practiced in community settings, and most respondents (58%, n=119) reported &gt;20 patients with MM under their personal care . 93 respondents (45%) had previously helped write institutional or societal guidelines, including 21 IMWG members.Respondents reported using once-weekly bortezomib most of the time (median 95% of patients, IQR 80%-100%) and almost always used SC bortezomib (IQR 100%-100%).There were no significant differences in bortezomib frequency or route based on academic vs community practice, experience with MM, US vs non-US, or LMIC vs non-LMIC. Large majorities of respondents (Table 1) felt that once-weekly bortezomib is preferred by patients (94%), associated with comparable durations of response (79%), and associated with less peripheral neuropathy (89%). Conversely, 61% of respondents felt that twice-weekly bortezomib in superior in newly diagnosed MM with acute cast nephropathy.Physician estimates of the incidence of any-grade peripheral neuropathy were significantly lower with once-weekly bortezomib (median 30%, IQR 20-43%) vs twice-weekly bortezomib (median 50%, IQR 40-73%). Similarly, Grade 3+ neuropathy estimates were significantly lower with once-weekly (median 10%, IQR 5-17%) vs twice-weekly bortezomib (median 25%, IQR 15-38%), with p&lt;0.001 in all cases . The most common cited barriers to ordering once-weekly bortezomib (Table 2) were perceived lack of prospective data (31%), difficulty modifying treatment orders (24%), and resistance from pharmacist colleagues who prefer adhering to trial-studied regimens (13%). Discussion: In our survey of over 200 MM-treating physicians from 38 countries (including 22 LMICs), once-weekly subcutaneous bortezomib was overwhelmingly preferred regardless of practice setting or country. The only exception was acute cast nephropathy, where twice-weekly bortezomib may expedite renal recovery and is reasonable to use initially. Neuropathy estimates were similar to published incidences (32% with once-weekly bortezomib vs 47% with twice-weekly bortezomib) from prospective data collected from the ALCYONE, GIMEMA-QW, and VISTA randomized trials (Mateos L&L 2020). Our findings highlight the widening mismatch between what physicians routinely prescribe to patients versus what registrational trials typically require. Given that &gt;90% of physicians personally prefer once-weekly bortezomib and that &gt;90% report that their patients feel similarly, once-weekly bortezomib appears to have become the global standard of care. This consensus should be taken into consideration for clinical trial design in the future.

Abstract Idecabtagene vicleucel (ide-cel) was the first chimeric antigen receptor T-cell therapy to gain US Food and Drug Administration approval for patients with relapsed/refractory multiple myeloma (RRMM). The clinical outcomes of standard of care (SOC) ide-cel in racially and ethnically diverse populations have been understudied. This study pooled data from 207 patients with RRMM (28% patients of racial and ethnic minority groups) treated with SOC ide-cel across 11 institutions to examine racial and ethnic differences in the incidence of toxicities and adverse events, response to ide-cel, and survival. This study included 22 (11%) Hispanic, 36 (17%) non-Hispanic Black, and 149 (72%) non-Hispanic White patients with RRMM. Compared with Hispanic and non-Hispanic White patients, non-Hispanic Black patients had higher median levels of C-reactive protein (1.0, 0.8, and 3.5 mg/dL, respectively; P = .02) and baseline ferritin (362.0 vs 307.0 vs 680.5, respectively; P = .08) and were more likely to develop cytokine release syndrome (77%, 85%, and 97%, respectively; P = .04). Although best overall response rate was lower among Hispanic patients (59%) than among non-Hispanic Black (86%) and White patients (86%; P = .01), there were no racial and ethnic differences in progression-free or overall survival. We provide, to our knowledge, the first and largest investigation of clinical outcomes of SOC ide-cel by race and ethnicity. Despite differences in safety and response to ide-cel, our findings encourage the use of ide-cel in all patients with RRMM. These findings should be confirmed in larger samples of diverse patients with RRMM, with longer follow-up time.

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 &lt;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