Impact of extramedullary multiple myeloma on outcomes with idecabtagene vicleucel.

Idecabtagene vicleucel (Ide-cel) has demonstrated excellent efficacy and durable responses in patients with relapsed/refractory multiple myeloma (RRMM). However, the outcomes with ide-cel in patients with extramedullary disease (EMD) remain incompletely characterized. We included patients with RRMM treated with ide-cel between May 2021 and April 2023 across 11 US academic institutions. Visceral or soft tissue lesions non-contiguous from bone was classified as EMD. Time-to-event analyses were performed from date of ide-cel infusion. Among 351 patients, 84 (24%) had EMD prior to infusion. The median follow-up from ide-cel infusion was 18.2 months (95% CI: 17-19.3). The day 90 overall response rates (ORR) were 52% vs. 82% for the EMD and non-EMD cohorts, respectively (p < 0.001). The median progression-free survival (PFS) was 5.3 months (95% CI: 4.1-6.9) for the EMD cohort vs. 11.1 months (95% CI: 9.2-12.6; p < 0.0001) for the non-EMD cohort. In a multivariable analysis, EMD was an independent predictor of inferior PFS [hazard ratio 1.5 (1.1-2.2), p = 0.02]. The median overall survival was 14.8 months [95% CI: 9-Not reached (NR)] vs. 26.9 months (26.3 vs. NR, p = 0.006) for the EMD and non-EMD cohorts, respectively. Extramedullary disease represents an independent predictor of inferior day 90 ORR and PFS among patients treated with ide-cel.

Absolute Lymphocyte Count after BCMA CAR-T Therapy is a Predictor of Response and Outcomes in Relapsed Multiple Myeloma.

BCMA-targeting CAR-T cells used in multiple myeloma (MM) are rapidly becoming a mainstay in the treatment of relapsed/refractory (RR) disease, and CAR-T cell expansion post-infusion has been shown to inform depth and duration of response, but measuring this process remains investigational. This multicenter study describes the kinetics and prognostic impact of absolute lymphocyte count (ALC) in the first 15 days after CAR-T infusion in 156 relapsed MM patients treated with the BCMA-targeting agents cilta-cel and ide-cel. Patients with higher maximum ALC (ALCmax) had better depth of response, progression-free survival (PFS), and duration of response (DoR). Patients with ALCmax >1.0 x103/uL had a superior PFS (30.5 versus 6 months, p <0.001) compared to those ≤1.0x103/uL, while patients with ALCmax ≤0.5 x103/uL represent a high-risk group with early disease progression and short PFS (HR 3.4, 95 CI: 2 -5.8, P <0.001). In multivariate analysis, ALCmax >1.0 x103/uL and non-paraskeletal extramedullary disease were the only independent predictors of PFS and DoR after accounting for ISS staging, age, CAR-T product, high-risk cytogenetics and number of previous lines. Moreover, our flow cytometry data suggests that ALC is a surrogate for BCMA CAR-T expansion and can be used as an accessible prognostic marker. We report for the first time the association of ALC after BCMA CAR-T infusion with clinical outcomes and its utility in predicting response in RRMM patients.

Prevalence and impact of diabetes on survival of patients with multiple myeloma in different racial groups.

ABSTRACT: Multiple myeloma (MM) is twice as common in Black individuals compared with in White individuals, and diabetes mellitus (DM) disproportionately affects Black patients. Although numerous studies have shown a correlation between DM and MM, this has not been studied in the context of race and in vivo mechanisms. We conducted a retrospective clinical study of 5383 patients with MM of which 15% had DM (White, 12% and Black, 25%). Multivariable Cox models showed reduced overall survival (OS) for patients with DM (hazard ratio, 1.27; 95% confidence interval, 1.11-1.47; P < .001). This appeared to be driven by a marked difference in OS between White patients with and without DM but not in Black patients. In contrast, obesity was associated with better OS in Black patients but not in White patients. To complement this analysis, we assessed MM growth in a genetically engineered immunocompromised nonobese diabetic (Rag1-/-/muscle creatinine kinase promoter expression of a human IGF1R [M] with a lysine [K] to arginine [R] point mutation) mouse model to evaluate the mechanisms linking DM and MM. MM.1S xenografts grew in more Rag1-/-/MKR mice and grew more rapidly in the Rag1-/-/MKR mice compared with in controls. Western blot analysis found that MM1.S xenografts from Rag1-/-/MKR mice had higher phosphorylated S6 ribosomal protein (Ser235/236) levels, indicating greater activation of the mammalian target of rapamycin pathway. Our study is, to our knowledge, the first to evaluate racial differences in DM prevalence and survival in MM, as well as the effect of DM on tumor growth in mouse models. Our results suggest that DM may contribute to the higher incidence of MM in Black patients; and to improve survival in MM, DM management cannot be ignored.

IVIg Use Associated with Ten-Fold Reduction of Serious Infections in Multiple Myeloma Patients Treated with Anti-BCMA Bispecific Antibodies.

BCMA-targeted bispecific antibodies (BiAb) are efficacious in relapsed/refractory multiple myeloma; however, serious infections have emerged as important toxicities. In this retrospective study, we characterized all infections and their risk factors, and evaluated the impact of infection prophylaxis in patients treated with BCMA-targeted BiAbs. Among 37 patients, 15 (41%) experienced a grade 3-5 infection, with two infection-related deaths during deep remissions. Most (84%) infections occurred during disease remissions. The cumulative probability of grade 3-5 infection increased over time with no plateau. Among responders (n = 26), profound hypogammaglobulinemia occurred in 100% and continued throughout the entire duration of treatment. During periods when patients were receiving intravenous immunoglobulin (IVIg), the rate of grade 3-5 infections was 90% lower than during observation (incidence rate ratio, 0.10; 95% confidence interval, 0.01-0.80; P = 0.0307). No other risk factors for infection were identified. This study demonstrates that profound hypogammaglobulinemia is universal with BCMA-targeted BiAbs, with intravenous immunoglobulin potentially abrogating most of the infection risk. SIGNIFICANCE: To the best of our knowledge, this is the first study to comprehensively analyze risk factors and mitigation strategies to prevent infections in myeloma patients receiving anti-BCMA bispecific antibodies. Profound and prolonged hypogammaglobulinemia was universal among responders, while immunoglobulin replacement was associated with 90% lower rates of grade 3-5 infections. See related commentary by Garfall and Stadtmauer, p. 427 . This article is featured in Selected Articles from This Issue, p. 419.

Trial designs and endpoints for immune therapies in multiple myeloma.

Immune therapies, including CAR-T cells, bispecific antibodies, and antibody-drug conjugates, are revolutionizing the treatment of multiple myeloma. In this review, we discuss clinical trial design considerations relevant to immune therapies. We first examine issues pertinent to specific populations, including elderly, patients with renal impairment, high-risk/extramedullary disease, and prior immune therapies. We then highlight trial designs to optimize the selection of dose and schedule, explore rational combination therapies based on preclinical data, and evaluate the nuances of commonly used endpoints. By exploiting their pharmacokinetic/pharmacodynamic profiles and utilizing novel translational insights, we can optimize the use of immune therapies in multiple myeloma.

Bridging advanced myeloma patients to subsequent treatments and clinical trials with classical chemotherapy and stem cell support.

Rapidly progressing relapsed/refractory multiple myeloma (RRMM) patients with compromised marrow have limited treatment options. Thus, non-myeloablative chemotherapy with a stem cell boost (SCB) may provide disease control and hematopoietic improvement as bridge to subsequent therapies. We identified 96 patients who received a SCB between January 2011 and December 2019 at the Mount Sinai Hospital. Patients had a median age of 64 years, received a median of 7 prior lines of therapy and 68 and 42% were triple-class and penta-drug refractory, respectively. Chemotherapy included melphalan (MEL) (n = 16), melphalan + carmustine (BCNU/MEL) (n = 52) or a variant of DCEP (dexamethasone, cyclophosphamide, etoposide, cisplatin) (n = 28). Median time to neutrophil recovery was 10 days and was significantly lower with DCEP (8 days) compared to MEL and BCNU/MEL (10-11 days) (p = 0.0047). Time to progression, progression-free survival and overall survival were 3.19, 2.7 and 8.38 months, respectively. The BCNU/MEL group had the highest response rate of 85% (p = 0.05), clinical benefit rate of 94% (p = 0.0014), progression-free survival of 3.3 months (p = 0.4) and overall survival of 8.7 months (p = 0.5). Sixty-six patients (69%) were bridged to new lines of therapy, including clinical trials. Non-myeloablative chemotherapy with SCB provides rapid disease control and marrow recovery with potential to receive further therapy.

Sequencing T-cell redirection therapies leads to deep and durable responses in patients with relapsed/refractory myeloma.

T-cell redirection therapy using chimeric antigen receptor (CAR) T cells and bispecific antibodies (BiAbs) has shown promising efficacy in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM), leading to the approval of 2 CAR T-cell products and numerous BiAb trials. Data on the outcomes after relapse following BiAbs are urgently required to develop strategies for sequencing salvage therapies. We identified 58 patients progressing after a BiAb trial at Mount Sinai Hospital. Progression-free survival (PFS) to the first salvage (PFS1), second salvage therapy (PFS2), and overall survival (OS) were estimated using the Kaplan-Meier method. The median age of the patients was 67 years, and 78% had high-risk cytogenetics. They had a median of 6 prior therapy lines, 89% were triple-class refractory, and 44% were penta-drug refractory. After the BiAb trial, patients were followed for a median of 30.5 months and received a median of 2 additional salvage therapies (range, 1-9). The most common first salvage was T-cell redirection in 19 patients (10 BiAb and 9 CAR T cells). Ten patients underwent T-cell redirection as a second salvage treatment. T-cell redirection therapy as first or second salvage was feasible and associated with a median PFS1 of 28.9 months, PFS2 of 30.9 months, and an OS of 62% at 2 years. The sequential use of different T-cell redirection therapies is possible and may lead to deep and durable responses following the relapse after BiAb therapy in RRMM.

Interventions and outcomes of patients with multiple myeloma receiving salvage therapy after BCMA-directed CAR T therapy.

B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T-cell (CAR T) therapy has demonstrated remarkable efficacy in patients with relapsed/refractory multiple myeloma, and now there are two US Food and Drug Administration-approved BCMA-directed CAR T products. However, despite high initial response rates, most patients eventually relapse. The outcomes of patients with disease recurrence after BCMA-directed CAR T have not been comprehensively studied, and such an analysis would help define optimal treatment strategies. We analyzed the salvage treatments and outcomes of 79 patients with multiple myeloma from two academic institutions, who had progression of disease after treatment with BCMA-directed CAR T. A total of 237 post-CAR T salvage treatment lines were used, and patients received a median of 2 (range, 1-10) treatment lines. The median overall survival from the date of relapse post-CAR T therapy was 17.9 months (95% confidence interval [CI], 14.0 non-estimable). The overall response rate to the first salvage regimen was 43.4%, with a median progression-free survival of 3.5 months (CI, 2.5-4.6). Thirty-five patients (44.3%) received a T-cell-engaging therapy (bispecific antibody or subsequent CAR T) as salvage treatment. The overall survival in patients who received subsequent T-cell-engaging therapy was not reached after a median follow up of 21.3 months. Patients with multiple myeloma who relapse after BCMA-directed CAR T have a limited prognosis but can be potentially treated with multiple lines of salvage therapy. T-cell-engaging therapies appear to maintain pronounced clinical activity in this setting.

A Three-Gene Signature Predicts Response to Selinexor in Multiple Myeloma.

PURPOSE: Selinexor is the first selective inhibitor of nuclear export to be approved for the treatment of relapsed or refractory multiple myeloma (MM). Currently, there are no known genomic biomarkers or assays to help select MM patients at higher likelihood of response to selinexor. Here, we aimed to characterize the transcriptomic correlates of response to selinexor-based therapy. METHODS: We performed RNA sequencing on CD138+ cells from the bone marrow of 100 patients with MM who participated in the BOSTON study, followed by differential gene expression and pathway analysis. Using the differentially expressed genes, we used cox proportional hazard models to identify a gene signature predictive of response to selinexor, followed by validation in external cohorts. RESULTS: The three-gene signature predicts response to selinexor-based therapy in patients with MM in the BOSTON cohort. Then, we validated this gene signature in 64 patients from the STORM cohort of triple-class refractory MM and additionally in an external cohort of 35 patients treated in a real-world setting outside of clinical trials. We found that the signature tracks with both depth and duration of response, and it also validates in a different tumor type using a cohort of pretreatment tumors from patients with recurrent glioblastoma. Furthermore, the genes involved in the signature, WNT10A, DUSP1, and ETV7, reveal a potential mechanism through upregulated interferon-mediated apoptotic signaling that may prime tumors to respond to selinexor-based therapy. CONCLUSION: In this study, we present a present a novel, three-gene expression signature that predicts selinexor response in MM. This signature has important clinical relevance as it could identify patients with cancer who are most likely to benefit from treatment with selinexor-based therapy.

Targeting Nuclear Export Proteins in Multiple Myeloma Therapy.

Nuclear export proteins such as exportin-1 (XPO1) transport tumor-suppressor proteins and other growth-regulatory proteins from the nucleus to the cytoplasm. Overexpression of XPO1 has been observed in several cancers and correlates with shorter event-free and overall survival in multiple myeloma. Selinexor was developed as an oral first-in-class selective inhibitor of nuclear export (SINE) that inhibits XPO1. Preclinical studies in tumor cell lines and mouse models have demonstrated the efficacy of selinexor both as a single agent and in various combinations with known active antimyeloma agents. Results from the pivotal phase II STORM trial led to the US FDA approval of selinexor with dexamethasone in penta-refractory myeloma. Because of the feasibility of combining selinexor with other active antimyeloma agents, the multiarm STOMP trial was initiated and is ongoing, with impressive response rates reported in some of the combination arms thus far. The registrational phase III BOSTON trial demonstrated the superiority of selinexor in combination with bortezomib and dexamethasone as compared with bortezomib and dexamethasone in patients with relapsed refractory multiple myeloma (RRMM) who have received one to three prior anti-MM regimens. The toxicity profile of selinexor is well established and predictable and may be significant unless managed aggressively and preemptively. The most common side effects are thrombocytopenia, anemia, neutropenia, fatigue, nausea, anorexia, and weight loss. Hyponatremia and cataracts seem to be class effects. Other SINE compounds are now being studied in efforts to discover agents that will potentially be better tolerated. Eltanexor is an investigational SINE compound that has shown a more positive toxicity profile in preclinical studies, with reduced central nervous system penetration and gastrointestinal side effects, and is now undergoing clinical investigation. These and other trials will further clarify the role of these innovative agents in the therapeutic advancement of RRMM.

The Safety and Efficacy of Radiation Therapy with Concurrent Dexamethasone, Cyclophosphamide, Etoposide, and Cisplatin-Based Systemic Therapy for Multiple Myeloma.

INTRODUCTION: The concurrent delivery of radiation therapy (RT) with salvage chemotherapies in the management of relapsed and refractory multiple myeloma (MM) is an area of ongoing investigation. This study examined the safety and efficacy of palliative RT given in the setting of concurrent dexamethasone, cyclophosphamide, etoposide, and cisplatin (DCEP). PATIENTS AND METHODS: Fifty-five patients with MM received RT to 64 different sites within three weeks of receiving DCEP from 2010 to 2020. A median dose of 20 Gray (range 8-32.5 Gy) was delivered in a median of 5 fractions (range 1-15). Patients received a median of 1 cycle (range 1-5) of DCEP. Rates of hematologic and RT toxicity were recorded along with pain, radiographic, and laboratory responses to treatment. RESULTS: RT was completed in 98% of patients. 21% of patients experienced RTOG grade 3+ hematologic toxicity before RT, which increased to 35% one-month post-RT (P = .13) before decreasing to 12% at 3 to 6 months (P = .02). The most common toxicity experienced was thrombocytopenia. Grade 1 to 2 non-hematologic RT-related toxicity was reported in 15% of patients while on treatment and fell to 6% one-month after completing RT. Pain resolved in 94% of patients with symptomatic lesions at baseline. Stable disease or better was observed in 34/39 (87%) of the targeted lesions on surveillance imaging. CONCLUSION: RT administered concurrently with DCEP was well-tolerated by most of the patients in this series, with low rates of hematologic and RT-related toxicity. RT was also very effective, with the vast majority of patients demonstrating resolution of their pain and a significant response on follow-up imaging.

Patient similarity network of newly diagnosed multiple myeloma identifies patient subgroups with distinct genetic features and clinical implications.

The remarkable genetic heterogeneity of multiple myeloma poses a substantial challenge for proper prognostication and clinical management of patients. Here, we introduce MM-PSN, the first multiomics patient similarity network of myeloma. MM-PSN enabled accurate dissection of the genetic and molecular landscape of the disease and determined 12 distinct subgroups defined by five data types generated from genomic and transcriptomic profiling of 655 patients. MM-PSN identified patient subgroups not previously described defined by specific patterns of alterations, enriched for specific gene vulnerabilities, and associated with potential therapeutic options. Our analysis revealed that co-occurrence of t(4;14) and 1q gain identified patients at significantly higher risk of relapse and shorter survival as compared to t(4;14) as a single lesion. Furthermore, our results show that 1q gain is the most important single lesion conferring high risk of relapse and that it can improve on the current International Staging Systems (ISS and R-ISS).

Bispecific Antibodies in Multiple Myeloma: Present and Future.

Despite many recent advances in therapy, there is still no plateau in overall survival curves in multiple myeloma. Bispecific antibodies are a novel immunotherapeutic approach designed to bind antigens on malignant plasma cells and cytotoxic immune effector cells. Early-phase clinical trials targeting B-cell maturation antigen (BCMA), GPRC5D, and FcRH5 have demonstrated a favorable safety profile, with mainly low-grade cytokine release syndrome, cytopenias, and infections. Although dose escalation is ongoing in several studies, early efficacy data show response rates in the most active dose cohorts between 61% and 83% with many deep responses; however, durability remains to be established. Further clinical trial data are eagerly anticipated. SIGNIFICANCE: Overall survival of triple-class refractory multiple myeloma remains poor. Bispecific antibodies are a novel immunotherapeutic modality with a favorable safety profile and impressive preliminary efficacy in heavily treated patients. Although more data are needed, bispecifics will likely become an integral part of the multiple myeloma treatment paradigm in the near future. Studies in earlier lines of therapy and in combination with other active anti-multiple myeloma agents will help further define the role of bispecifics in multiple myeloma.

A combination of carfilzomib, dexamethasone, and daratumumab for treatment of adult patients with relapsed/refractory multiple myeloma in two dosing regimens: once-weekly and twice-weekly.

INTRODUCTION: Despite the development of new therapeutic agents, relapsed/refractory multiple myeloma (RRMM) is associated with poor survival outcomes. Furthermore, many patients develop resistance to immunomodulatory drugs (IMiD), creating a need for IMiD-free regimens. Areas covered: This review focuses on the combination of carfilzomib, dexamethasone, and daratumumab (KdD or DKd) which has shown promising results in patients with RRMM who have tried multiple lines of therapy, and has been approved in the U.S., EU, and Japan. The KdD triplet has two recommended dosage regimens, carfilzomib once-weekly (KdD70 QW) and carfilzomib twice-weekly (KdD56 BIW), with comparable efficacy and safety profiles. Expert opinion: These options provide flexibility to patients and healthcare providers, especially in the era of COVID-19. Carfilzomib-based regimens remain a standard of care based on multiple randomized phase 3 studies. Additional studies are currently underway investigating carfilzomib-based regimens such as KdD combined with novel agents. Nevertheless, KdD is one of the most efficacious options for patients with RRMM.

Selinexor, bortezomib, and dexamethasone versus bortezomib and dexamethasone in previously treated multiple myeloma: Outcomes by cytogenetic risk.

In the phase 3 BOSTON study, patients with multiple myeloma (MM) after 1-3 prior regimens were randomized to once-weekly selinexor (an oral inhibitor of exportin 1 [XPO1]) plus bortezomib-dexamethasone (XVd) or twice-weekly bortezomib-dexamethasone (Vd). Compared with Vd, XVd was associated with significant improvements in median progression-free survival (PFS), overall response rate (ORR), and lower rates of peripheral neuropathy, with trends in overall survival (OS) favoring XVd. In BOSTON, 141 (35.1%) patients had MM with high-risk (presence of del[17p], t[4;14], t[14;16], or ≥4 copies of amp1q21) cytogenetics (XVd, n = 70; Vd, n = 71), and 261 (64.9%) exhibited standard-risk cytogenetics (XVd, n = 125; Vd, n = 136). Among patients with high-risk MM, median PFS was 12.91 months for XVd and 8.61 months for Vd (HR, 0.73 [95% CI, (0.4673, 1.1406)], p = 0.082), and ORRs were 78.6% and 57.7%, respectively (OR 2.68; p = 0.004). In the standard-risk subgroup, median PFS was 16.62 months for XVd and 9.46 months for Vd (HR 0.61; p = 0.004), and ORRs were 75.2% and 64.7%, respectively (OR 1.65; p = 0.033). The safety profiles of XVd and Vd in both subgroups were consistent with the overall population. These data suggest that selinexor can confer benefits to patients with MM regardless of cytogenetic risk. ClinicalTrials.gov identifier: NCT03110562.

B-cell maturation antigen (BCMA) in multiple myeloma: the new frontier of targeted therapies.

Outcomes of patients with multiple myeloma (MM) who become refractory to standard therapies are particularly poor and novel agents are greatly needed to improve outcomes in such patients. B-cell maturation antigen (BCMA) has become an important therapeutic target in MM with three modalities of treatment in development including antibody-drug conjugates (ADCs), bispecific T-cell engagers (BITEs), and chimeric antigen receptor (CAR) T-cell therapies. Early clinical trials of anti-BCMA immunotherapeutics have demonstrated extremely promising results in heavily pretreated patients with relapsed/refractory MM (RRMM). Recently, belantamab mafodotin was the first anti-BCMA therapy to obtain approval in relapsed/refractory MM. This review summarizes the most updated efficacy and safety data from clinical studies of BCMA-targeted therapies with a focus on ADCs and BITEs. Additionally, important differences among the BCMA-targeted treatment modalities and their clinical implications are discussed.

Efficacy of Intravenous Immunoglobulin for Preventing Infections in Patients with Multiple Myeloma.

INTRODUCTION: Despite many recent advances in the treatment of multiple myeloma (MM), infection remains a major cause of morbidity and mortality. Prior studies have shown mixed results using intravenous immunoglobulin (IVIG) to prevent infections in MM and were conducted prior to most modern MM therapies. PATIENTS AND METHODS: We retrospectively reviewed all patients with MM treated with IVIG at our institution from 2010 to 2017. The primary endpoint was the incidence rate ratio (IRR) of infectious events (IEs) per patient-year during IVIG versus observation. RESULTS: A total of 68 patients were included; 151 IEs occurred during 918 months of IVIG treatment, whereas 446 IEs occurred during 2484 months of observation. Although the annual rate of IEs was substantially higher during periods of progressive disease (PD) compared with non-PD (4.9 vs. 1.8; P < .001), most IEs occurred during periods of non-PD (75% vs. 25% during PD). There was no overall difference in the annual rate of IEs per patient between IVIG and observation (1.97 vs. 2.16; IRR, 0.92; 95% confidence interval [CI], 0.76-1.10; P = .376). The subgroup of patients with hypogammaglobulinemia and whose myeloma was in a non-PD phase had a significant reduction in all-grade IEs (1.20 vs. 1.92; IRR, 0.63; 95% CI, 0.45-0.88; P = .009) and ≥ grade 3 IEs (0.25 vs. 0.56; IRR, 0.45; 95% CI, 0.22-0.94; P = .041) with IVIG compared with observation. CONCLUSION: Although treatment with IVIG did not show benefit in the overall population, there may be subgroups of patients that derive significant benefit. Additional observational studies are needed to confirm these findings and further refine patient selection.

Phase 1b trial of isatuximab, an anti-CD38 monoclonal antibody, in combination with carfilzomib as treatment of relapsed/refractory multiple myeloma.

BACKGROUND: Isatuximab (Isa), an anti-CD38 monoclonal antibody, and carfilzomib (K), a next-generation proteasome inhibitor (PI), both have potent single-agent activity in relapsed and refractory multiple myeloma (RRMM). METHODS: This phase 1b study evaluated the combination of Isa and K in 33 patients with RRMM. Isa was administered by intravenous infusion in 3 dosing cohorts: dose level 1 (Isa at 10 mg/kg biweekly), dose level 2 (DL2; Isa at 10 mg/kg weekly for 4 doses and then biweekly), and dose level 3 (Isa at 20 mg/kg weekly for 4 doses and then biweekly) and all patients received K (20 mg/m2 intravenously for cycle 1, days 1 and 2, and then 27 mg/m2 for all subsequent doses). A standard 3+3 dose-escalation design was used, no dose-limiting toxicity was observed, and the maximum tolerated dose was not reached. An expansion cohort of 18 patients was enrolled at DL2 to further evaluate safety and efficacy. Responses were assessed with the International Myeloma Working Group response criteria, and patients continued treatment until disease progression or unacceptable toxicity. RESULTS: With a median follow-up of 26.7 months, in this heavily pretreated population with a median of 3 prior lines (refractory to PIs and immunomodulatory drugs, 76%; refractory to K, 27%), the overall response rate was 70% (stringent complete response/complete response, 4; very good partial response, 8; partial response, 11). The median progression-free survival was 10.1 months, and the 2-year survival probability was 76%. The most common treatment-related adverse events (grade 2 or higher) were anemia, leukopenia, neutropenia, thrombocytopenia, hypertension, and infection. Infusion reactions were common (55%) but did not limit dosing. CONCLUSIONS: Treatment with Isa plus K was well tolerated with no unexpected toxicity. The combination was effective despite the enrollment of heavily pretreated patients with RRMM. LAY SUMMARY: This phase 1b study was designed to assess the safety, pharmacokinetics, and preliminary efficacy of isatuximab and carfilzomib in patients with relapsed and refractory multiple myeloma. Thirty-three patients were treated: 15 in dose escalation and 18 in dose expansion. Patients received an average of 10 cycles. The treatment was safe and effective. No unexpected toxicity or drug-drug interactions were noted. Seventy percent of the subjects responded to therapy, and the progression-free survival was 10.1 months.

Subcutaneous daratumumab and hyaluronidase-fihj in newly diagnosed or relapsed/refractory multiple myeloma.

Daratumumab, a human immunoglobulin G1 kappa monoclonal antibody that targets CD38, is currently approved as monotherapy and in varying combinations with approved anti-myeloma regimens in both newly diagnosed multiple myeloma and relapsed refractory multiple myeloma. Originally developed for intravenous administration, the subcutaneous formulation of daratumumab (daratumumab and hyaluronidase-fihj) was recently approved by the US Federal Drug Administration and European Commission in 2020. In clinical trials, compared with the intravenous formulation, subcutaneous daratumumab (Dara-SC) has significantly shorter administration time (median first dose 7 h versus 3-5 min, respectively), lower rates of infusion-related reactions (median first dose 50% versus less than 10%, respectively), and lower volume of infusion (median 500-1000 ml versus 15 ml, respectively). Otherwise, the pharmacokinetics, safety profile, and efficacy are comparable. This review summarizes the pivotal trials that led to the approval of Dara-SC, highlights important clinical considerations for the use of Dara-SC, and provides practical guidelines for the administration of Dara-SC in the clinic.