Management of multiple myeloma presenting as malignant spinal cord compression during pregnancy: a case report.

not included as this is letter to the editor.

Outcomes of melphalan 140 mg/m2 followed by autologous stem cell transplantation in multiple myeloma patients with co-morbidities: Single-centre experience.

High-dose melphalan followed by stem cell rescue is the standard consolidative therapy for transplant-eligible patients with multiple myeloma (MM) in the United Kingdom. A melphalan dose of 200 mg/m2 (Mel200) is considered the "gold standard" for autologous stem cell transplant (ASCT) conditioning for fit patients ≤70 years old; however, with a peak diagnosis incidence at 80-89 years old in the UK dose adjustments will be inevitable to limit toxicities. In this single-centre UK-based retrospective analysis, data was collected from patients with plasma cell dyscrasias who underwent a first reduced-intensity, Mel140, ASCT from 2006 to 2019, a total of 81 patients. We found that the procedure was overall safe with seven (9%) of patients requiring ITU admission and a single transplant-related death within the initial autograft admission. The progression-free survival (PFS) and overall survival were comparable with those previously reported in the literature with median PFS for our cohort of 31 months. Univariate analysis of our data showed an inferior PFS for patients aged ≥70 years. In conclusion, although this is a retrospective analysis, it demonstrates that dose-reduced melphalan conditioning is safe and effective in patients deemed unfit for standard-intensity conditioning.

The impact of continuous lenalidomide maintenance treatment on people living with multiple myeloma-a single-centre, qualitative service evaluation study.

PURPOSE: Continuous lenalidomide maintenance treatment after autologous stem cell transplantation delivers improvement in progression free and overall survival among newly diagnosed multiple myeloma patients and has been the standard of care in the UK since March 2021. However, there is scant information about its impact on patients' day-to-day lives. This service evaluation aimed to qualitatively assess patients receiving lenalidomide treatment at a cancer centre in London, in order that the service might better align with needs and expectations of patients. METHODS: We conducted 20 semi-structured interviews among myeloma patients who were on continuous lenalidomide maintenance treatment at a specialist cancer centre in London. Members of the clinical team identified potentially eligible participants to take part, and convenience sampling was used to select 10 male and 10 female patients, median age of 58 (range, 45-71). The median treatment duration was 11 months (range, 1-60 months). Participants were qualitatively interviewed following the same semi-structured interview guide, which was designed to explore patient experience and insights of lenalidomide. Reflexive thematic analysis was used for data analysis. RESULTS: Four overarching themes were as follows: (i) lenalidomide: understanding its role and rationale; (ii) reframing the loss of a treatment-free period to a return to normal life; (iii) the reality of being on lenalidomide: balancing hopes with hurdles; (iv) gratitude and grievances: exploring mixed perceptions of care and communication. Results will be used to enhance clinical services by tailoring communication to better meet patients' preferences when making treatment decisions. CONCLUSION: This study highlights that most patients feel gratitude for being offered continuous lenalidomide and perceive it as alleviating some fears concerning relapse. It reveals variations in side effects in different age groups; younger patients reported no/negligible side effects, whilst several older patients with comorbidities described significant symptom burden, occasionally leading to treatment discontinuation which caused distress at the perceived loss of prolonged remission. Future research should prioritise understanding the unique needs of younger patients living with multiple myeloma.

Clinical Management of Patients With Relapsed/Refractory Multiple Myeloma Treated With Talquetamab.

BACKGROUND: Talquetamab is a bispecific antibody targeting the multiple myeloma-associated antigen G protein-coupled receptor family C group 5 member D (GPRC5D). In the phase 1/2 MonumenTAL-1 trial (NCT03399799/NCT04634552), overall responses rates were > 71% in patients with triple-class exposed relapsed/refractory multiple myeloma (RRMM). Due to the distribution of the target antigen, a unique pattern of GPRC5D-associated adverse events (AEs) was observed, together with T-cell redirection-associated AEs. Management strategies for talquetamab-associated AEs are described. DISCUSSION: GPRC5D-associated AEs included dermatologic (rash, nonrash, and nail toxicities) and oral AEs (dysgeusia, dysphagia, and dry mouth). The incidence of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were consistent with other T-cell redirection therapies. The incidence of high-grade infections was lower than observed with B-cell maturation antigen-targeting bispecific antibodies, with less frequent use of intravenous immunoglobulin required. GPRC5D-associated AEs were mostly low grade and led to few discontinuations. Skin toxicities were managed with emollients, topical corticosteroids, and oral corticosteroids (for high-grade, persistent, or AEs that progress). Nail toxicities were commonly managed with emollients. Based on investigator experience, dose modification may be effective for controlling oral events. Observation for potential weight changes is required. Infections were managed per standard of care. CRS and ICANS were effectively managed, consistent with other trials of T-cell redirection therapies. CONCLUSION: Although talquetamab had a distinct safety profile, AEs were considered clinically manageable and mostly low grade. With appropriate education and support, health care practitioners can ensure patients with RRMM maintain quality of life and treatment adherence. VIDEO ABSTRACT.

International Myeloma Working Group immunotherapy committee consensus guidelines and recommendations for optimal use of T-cell-engaging bispecific antibodies in multiple myeloma.

Multiple myeloma remains an incurable disease, despite the development of numerous drug classes and combinations that have contributed to improved overall survival. Immunotherapies directed against cancer cell-surface antigens, such as chimeric antigen receptor (CAR) T-cell therapy and T-cell-redirecting bispecific antibodies, have recently received regulatory approvals and shown unprecedented efficacy. However, these immunotherapies have unique mechanisms of action and toxicities that are different to previous treatments for myeloma, so experiences from clinical trials and early access programmes are essential for providing specific recommendations for management of patients, especially as these agents become available across many parts of the world. Here, we provide expert consensus clinical practice guidelines for the use of bispecific antibodies for the treatment of myeloma. The International Myeloma Working Group is also involved in the collection of prospective real-time data of patients treated with such immunotherapies, with the aim of learning continuously and adapting clinical practices to optimise the management of patients receiving immunotherapies.

Teclistamab Improves Patient-Reported Symptoms and Health-Related Quality of Life in Relapsed or Refractory Multiple Myeloma: Results From the Phase II MajesTEC-1 Study.

INTRODUCTION: Patients with relapsed or refractory multiple myeloma (RRMM) report significantly lower HRQoL compared with patients with newly diagnosed MM and experience further deterioration in HRQoL with each relapse and subsequent treatment. Therefore, consideration of the impact of treatment on HRQoL in addition to clinical outcomes is vital. PATIENTS AND METHODS: In the phase I/II MajesTEC-1 (NCT03145181, NCT04557098) study, patients with RRMM who received teclistamab, an off-the-shelf, T-cell redirecting BCMA × CD3 bispecific antibody, had deep and durable responses with manageable safety. HRQoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire core 30-item and the EuroQol 5 Dimension 5 Level descriptive questionnaire. Changes over time from baseline were measured with a repeated measures mixed-effects model. Proportions of patients with clinically meaningful improvement after starting treatment and time to clinically meaningful worsening were assessed. RESULTS: Compliance was maintained throughout the study. Compared with baseline, positive changes were observed for pain, global health status, and emotional functioning with treatment; other assessments were largely unchanged from baseline. Post hoc analysis showed patients with deeper clinical response generally reported improved HRQoL outcomes. Following an initial decline in HRQoL in some scales, the proportion of patients reporting clinically meaningful improvements increased, while the proportion reporting clinically meaningful worsening decreased over time. Clinically meaningful improvements in pain were reported in ≥40% of patients at most assessment time points. CONCLUSIONS: These results complement previously reported clinical benefits and support teclistamab as a promising therapeutic option for patients with RRMM.

Treatment preferences of patients with relapsed or refractory multiple myeloma in the United States, United Kingdom, Italy, Germany, France, and Spain: results from a discrete choice experiment.

Introduction: Newer treatment options for relapsed/refractory multiple myeloma (RRMM) with efficacy and safety profiles that differ from traditional therapies have facilitated personalized management strategies to optimize patient outcomes. In the context of such personalized management, understanding how treatment characteristics influence patients' preferences is essential. This study assessed patients' preferences for RRMM treatment attributes and determined trade-offs between potential benefits, administration procedures, and adverse effects. Methods: Patients' preferences were evaluated using a discrete choice experiment (DCE). Patients with RRMM who reported failing two lines of anti-myeloma treatment (immunomodulatory agent and a proteasome inhibitor [PI]) or ≥ 3 lines (including ≥1 PI, immunomodulatory agent, or anti-CD38 monoclonal antibody), were recruited across the US, UK, Italy, Germany, France, and Spain. DCE attributes and levels were identified using a targeted literature review, a review of clinical data for relevant RRMM treatments, qualitative patient interviews, and input from clinical and myeloma patient experts. The DCE was administered within an online survey from February-June 2022. Preference data were analyzed using an error-component logit model and willingness to make trade-offs for potential benefits, and relative attribute importance scores were calculated. Results: Overall, 296 patients from the US (n = 100), UK (n = 49), Italy (n = 45), Germany (n = 43), France (n = 39), and Spain (n = 20) participated in the DCE. Mean (standard deviation) age was 63.8 (8.0) years, 84% had a caregiver, and patients had a median of 3 (range: 2-8) prior lines of therapy. Efficacy attributes most influenced patients' preferences, with increasing overall response rate (25-85%) and overall survival (6 months to 2 years) contributing to ~50% of treatment decision-making. Administration procedures were also considered important to patients. Avoiding individual side effects was considered relatively less important, with patients willing to tolerate increases in side effects for gains in efficacy. Patient characteristics such as rate of disease progression, sociodemographics, or clinical characteristics also influenced treatment preferences. Conclusion: Patients with RRMM were willing to tolerate increased risk of side effects for higher efficacy. Preferences and risk tolerance varied between patients, with preference patterns differing by certain patient characteristics. This highlights the importance of shared decision-making for optimal treatment selection and patient outcomes.

Patient-reported experiences during and following treatment with belantamab mafodotin for relapsed/refractory multiple myeloma in the DREAMM-2 study.

Introduction: Patients with relapsed or refractory multiple myeloma (RRMM) are likely to be living with persistent symptoms, especially bone pain and fatigue, and experiencing restrictions in their physical and social functioning, which reduce health-related quality of life. Methods: This qualitative interview study evaluated patients' perspectives about living with RRMM and their treatment with belantamab mafodotin, using interviews embedded in the Phase II DREAMM-2 trial (NCT03525678) with belantamab mafodotin. Patients consented to participate in up to 2 recorded telephone interviews (at treatment cycle 4 [C4] and at end of treatment [EOT]) comprising open-ended questions. Results: A total of 142 interviews were conducted with 111 unique patients. At C4, common symptoms included neuropathy, fatigue, and bone or joint pain. Improvements in symptom severity were reported by patients who responded to belantamab mafodotin. Symptoms associated with visual impairment, eye irritation, and eye pain reported during the trial were reported to be at- or near-resolution by the EOT interview. Regarding impacts of underlying MM, patients most commonly expressed concerns about changes in daily performance and lifestyle for both responders (67.5% of all impact expressions) and non-responders (63.2%). Overall, interview participants reported being satisfied with belantamab mafodotin treatment. Discussion: This qualitative patient interview study provides valuable insight into patients' symptomatic experience with belantamab mafodotin for their RRMM treatment and may help healthcare providers better anticipate their patients' real-world experience and needs when prescribing this novel agent in the clinic.

Patient-Reported Outcomes With Belantamab Mafodotin Treatment in Patients With Triple-Class Refractory Multiple Myeloma.

In the randomized phase II DREAMM-2 study, single-agent belantamab mafodotin demonstrated deep and durable responses and a manageable safety profile in triple-class refractory relapsed/refractory multiple myeloma (RRMM). We present patient-reported outcomes (PROs) from this study for patients treated with the approved dose of belantamab mafodotin (2.5 mg/kg q3w). Disease and treatment-related symptoms, health-related quality of life (HRQOL), functioning, and patient-reported ocular changes were assessed using questionnaires (European Organisation for Research and Treatment of Cancer Quality of Life questionnaires EORTC-QLQ-C30 and EORTC-QLQ-MY20, Ocular Surface Disease Index [OSDI], and the National Eye Institute Visual Functioning Questionnaire 25 [NEI VFQ-25]) at baseline, during treatment (every 3 or 6 weeks), and at the end of treatment (EOT). Eye examinations were conducted at baseline, prior to each treatment cycle, and at EOT. Patients reported ocular symptoms in the OSDI and NEI VFQ-25 questionnaires, with the median time to worst severity of 45 to 64 days depending on symptoms considered. Some limitations in driving and reading were reported. Ocular symptoms were improved and median time to recovery was 23.5 to 44.0 days. EORTC-QLQ-C30 data suggest core MM symptoms (including fatigue and pain), overall HRQOL, and patient functioning were maintained while patients continued belantamab mafodotin treatment, even if meaningful worsening of vision-related symptoms occurred. These PRO results, together with the clinical efficacy of belantamab mafodotin, support its use in patients with RRMM and further evaluation of its use at earlier lines of therapy.

Single-agent belantamab mafodotin in patients with relapsed/refractory multiple myeloma: Final analysis of the DREAMM-2 trial.

BACKGROUND: Patients with relapsed/refractory multiple myeloma (RRMM) have a high unmet treatment need. Belantamab mafodotin (belamaf), a first-in-class, B-cell maturation antigen-binding antibody-drug conjugate, eliminates myeloma cells through direct cell killing and an anti-myeloma immune response. METHODS: DREAMM-2 (NCT03525678) was a phase 2, two-arm, open-label trial in patients with heavily pretreated RRMM who had three or more prior therapies, were refractory to an immunomodulatory agent and a proteasome inhibitor, and refractory or intolerant to an anti-CD38 monoclonal antibody. Belamaf was given at 2.5 or 3.4 mg/kg every 3 weeks. The primary end point was overall response rate (ORR); secondary end points included progression-free survival (PFS), overall survival (OS), safety, ocular symptoms, and health-related quality of life (HRQOL). RESULTS: This final analysis (cutoff date, March 31, 2022), N = 223, with median follow-up of 12.5 and 13.8 months, demonstrated an ORR of 32% and 35%, median PFS of 2.8 and 3.9 months, and median OS of 15.3 and 14.0 months in the 2.5 mg/kg and 3.4 mg/kg cohorts, respectively. Median duration of response was 12.5 and 6.2 months. No new safety signals were observed; the most common Grade 3 and 4 adverse events were keratopathy (29% vs. 25%), thrombocytopenia (22% vs. 29%), and anemia (21% vs. 28%). HRQOL outcomes suggest that overall global health status/quality of life, physical and role functioning, and overall disease symptoms were maintained or improved during treatment. CONCLUSIONS: This final analysis of DREAMM-2 confirms that in patients with triple-class refractory RRMM, single-agent belamaf results in durable and clinically meaningful responses with a manageable safety profile.

Mezigdomide plus Dexamethasone in Relapsed and Refractory Multiple Myeloma.

BACKGROUND: Despite recent progress, multiple myeloma remains incurable. Mezigdomide is a novel cereblon E3 ubiquitin ligase modulator with potent antiproliferative and tumoricidal activity in preclinical models of multiple myeloma, including those resistant to lenalidomide and pomalidomide. METHODS: In this phase 1-2 study, we administered oral mezigdomide in combination with dexamethasone to patients with relapsed and refractory myeloma. The primary objectives of phase 1 (dose-escalation cohort) were to assess safety and pharmacokinetics and to identify the dose and schedule for phase 2. In phase 2 (dose-expansion cohort), objectives included the assessment of the overall response (partial response or better), safety, and efficacy of mezigdomide plus dexamethasone at the dose and schedule determined in phase 1. RESULTS: In phase 1, a total of 77 patients were enrolled in the study. The most common dose-limiting toxic effects were neutropenia and febrile neutropenia. On the basis of the phase 1 findings, investigators determined the recommended phase 2 dose of mezigdomide to be 1.0 mg, given once daily in combination with dexamethasone for 21 days, followed by 7 days off, in each 28-day cycle. In phase 2, a total of 101 patients received the dose identified in phase 1 in the same schedule. All patients in the dose-expansion cohort had triple-class-refractory multiple myeloma, 30 patients (30%) had received previous anti-B-cell maturation antigen (anti-BCMA) therapy, and 40 (40%) had plasmacytomas. The most common adverse events, almost all of which proved to be reversible, included neutropenia (in 77% of the patients) and infection (in 65%; grade 3, 29%; grade 4, 6%). No unexpected toxic effects were encountered. An overall response occurred in 41% of the patients (95% confidence interval [CI], 31 to 51), the median duration of response was 7.6 months (95% CI, 5.4 to 9.5; data not mature), and the median progression-free survival was 4.4 months (95% CI, 3.0 to 5.5), with a median follow-up of 7.5 months (range, 0.5 to 21.9). CONCLUSIONS: The all-oral combination of mezigdomide plus dexamethasone showed promising efficacy in patients with heavily pretreated multiple myeloma, with treatment-related adverse events consisting mainly of myelotoxic effects. (Funded by Celgene, a Bristol-Myers Squibb Company; CC-92480-MM-001 ClinicalTrials.gov number, NCT03374085; EudraCT number, 2017-001236-19.).

Infections following bispecific antibodies in myeloma: a systematic review and meta-analysis.

Bispecific antibodies, a novel immunotherapy with promising efficacy against multiple myeloma, form immune synapses between T-cell surface marker CD3 and malignant cell markers, including B-cell maturation antigen (BCMA), FcRH5, and G protein-coupled receptor GPRC5D. These bispecific antibodies so effectively deplete plasma cells (and to some extent T-cells) that patients are at increased risk of developing infections. A systematic review and meta-analysis of infections in published studies of patients with myeloma treated with bispecific antibodies was conducted to better characterize the infection risks. A literature search used MEDLINE, EMBASE, and Cochrane to identify relevant studies between inception and February 10, 2023, including major conference presentations. Phase 1b-3 clinical trials and observational studies were included. Sixteen clinical trials comprising 1666 patients were included. Median follow-up was 7.6 months and 38% of the cohort had penta-drug refractory disease. Pooled prevalence of all-grade infections was 56%, whereas the prevalence of grade ≥3 infections was 24%. Patients who were treated with BCMA-targeted bispecifics had significantly higher rates of grade ≥3 infections than non-BCMA bispecifics (25% vs 20%). Similarly, patients treated with bispecifics in combination with other agents had significantly higher rate of all-grade infection than those receiving monotherapy (71% vs 52%). In observational studies (n = 293), excluded from the primary analysis to ensure no overlap with patients in clinical trials, several infections classically associated with T-cell depletion were identified. This systematic review identifies BCMA-targeted bispecifics and bispecific combination therapy as having higher infection risk, requiring vigilant infection screening and prophylaxis strategies.

Limited efficacy of APRIL CAR in patients with multiple myeloma indicate challenges in the use of natural ligands for CAR T-cell therapy.

BACKGROUND: We used a proliferating ligand (APRIL) to construct a ligand-based third generation chimeric antigen receptor (CAR) able to target two myeloma antigens, B-cell maturation antigen (BCMA) and transmembrane activator and CAML interactor. METHODS: The APRIL CAR was evaluated in a Phase 1 clinical trial (NCT03287804, AUTO2) in patients with relapsed, refractory multiple myeloma. Eleven patients received 13 doses, the first 15×106 CARs, and subsequent patients received 75,225,600 and 900×106 CARs in a 3+3 escalation design. RESULTS: The APRIL CAR was well tolerated. Five (45.5%) patients developed Grade 1 cytokine release syndrome and there was no neurotoxicity. However, responses were only observed in 45.5% patients (1×very good partial response, 3×partial response, 1×minimal response). Exploring the mechanistic basis for poor responses, we then compared the APRIL CAR to two other BCMA CARs in a series of in vitro assays, observing reduced interleukin-2 secretion and lack of sustained tumor control by APRIL CAR regardless of transduction method or co-stimulatory domain. There was also impaired interferon signaling of APRIL CAR and no evidence of autoactivation. Thus focusing on APRIL itself, we confirmed similar affinity to BCMA and protein stability in comparison to BCMA CAR binders but reduced binding by cell-expressed APRIL to soluble BCMA and reduced avidity to tumor cells. This indicated either suboptimal folding or stability of membrane-bound APRIL attenuating CAR activation. CONCLUSIONS: The APRIL CAR was well tolerated, but the clinical responses observed in AUTO2 were disappointing. Subsequently, when comparing the APRIL CAR to other BCMA CARs, we observed in vitro functional deficiencies due to reduced target binding by cell-expressed ligand.

Impact of timing of stem cell return following high dose melphalan in multiple myeloma patients with renal impairment: a single center experience.

High dose melphalan (HDM) followed by autologous stem cell transplantation (ASCT) remains the standard consolidation in transplant eligible multiple myeloma (MM) patients. The timing between HDM administration and hematopoietic stem cell return (HSCR) varies among institutions, with a 'rest period' of 48 hours (h) employed by some for patients with renal impairment (RI). We investigated the differences in hematopoietic recovery and HDM toxicity between MM patients with RI who had HSCR after 24 vs 48 h from HDM. Fifty MM patients with RI (48 h group; n = 31 and 24 h group; n = 19) were included. No statistically significant differences were noted in surrogates for hematopoietic recovery and HDM toxicity between both groups. Only one death occurred in the 24 h group. No patients required renal replacement therapy. Therefore, a 24 h period between HDM and AHSC infusion appears safe for MM patients with RI.

Cilta-cel or Standard Care in Lenalidomide-Refractory Multiple Myeloma.

BACKGROUND: Ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen (BCMA)-directed CAR T-cell therapy, is effective in heavily pretreated patients with relapsed or refractory multiple myeloma. We investigated cilta-cel in earlier treatment lines in patients with lenalidomide-refractory disease. METHODS: In this phase 3, randomized, open-label trial, we assigned patients with lenalidomide-refractory multiple myeloma to receive cilta-cel or the physician's choice of effective standard care. All the patients had received one to three previous lines of treatment. The primary outcome was progression-free survival. RESULTS: A total of 419 patients underwent randomization (208 to receive cilta-cel and 211 to receive standard care). At a median follow-up of 15.9 months (range, 0.1 to 27.3), the median progression-free survival was not reached in the cilta-cel group and was 11.8 months in the standard-care group (hazard ratio, 0.26; 95% confidence interval [CI], 0.18 to 0.38; P<0.001). Progression-free survival at 12 months was 75.9% (95% CI, 69.4 to 81.1) in the cilta-cel group and 48.6% (95% CI, 41.5 to 55.3) in the standard-care group. More patients in the cilta-cel group than in the standard-care group had an overall response (84.6% vs. 67.3%), a complete response or better (73.1% vs. 21.8%), and an absence of minimal residual disease (60.6% vs. 15.6%). Death from any cause was reported in 39 patients and 46 patients, respectively (hazard ratio, 0.78; 95% CI, 0.5 to 1.2). Most patients reported grade 3 or 4 adverse events during treatment. Among the 176 patients who received cilta-cel in the as-treated population, 134 (76.1%) had cytokine release syndrome (grade 3 or 4, 1.1%; no grade 5), 8 (4.5%) had immune effector cell-associated neurotoxicity syndrome (all grade 1 or 2), 1 had movement and neurocognitive symptoms (grade 1), 16 (9.1%) had cranial nerve palsy (grade 2, 8.0%; grade 3, 1.1%), and 5 (2.8%) had CAR-T-related peripheral neuropathy (grade 1 or 2, 2.3%; grade 3, 0.6%). CONCLUSIONS: A single cilta-cel infusion resulted in a lower risk of disease progression or death than standard care in lenalidomide-refractory patients with multiple myeloma who had received one to three previous therapies. (Funded by Janssen and Legend Biotech; CARTITUDE-4 ClinicalTrials.gov number, NCT04181827.).

Plain language summary of the MajesTEC-1 study of teclistamab for the treatment of people with relapsed or refractory multiple myeloma.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of a phase 1-2 clinical trial called MajesTEC-1. This trial tested the cancer drug teclistamab in people with relapsed or refractory multiple myeloma, a cancer that forms in a certain type of white blood cells known as plasma cells. Most participants who took part in the study had at least 3 prior treatments for multiple myeloma before their cancer came back. HOW WAS THE STUDY IN THIS SUMMARY CONDUCTED?: A total of 165 participants from 9 countries were included in this study. All participants were given teclistamab once per week and monitored for side effects. Once participants started taking teclistamab, they were checked regularly to monitor if their cancer had no change, improved (responded to treatment), or worsened or spread (known as disease progression). WHAT WERE THE RESULTS OF THE STUDY?: After approximately 14.1 months of follow-up (from 2020 to 2021), 63% of participants who were given teclistamab had a decrease in myeloma burden, meaning that they responded to treatment with teclistamab. Participants who responded to teclistamab lived without their myeloma coming back for approximately 18.4 months. The most common side effects were infections, cytokine release syndrome, abnormally low white and red blood cell counts (neutropenia, lymphopenia, and anemia), and low platelet cell counts (thrombocytopenia). Approximately 65% of participants experienced serious side effects. WHAT DO THE RESULTS OF THIS STUDY MEAN?: Overall, more than half of the participants (63%) in the MajesTEC-1 study responded to treatment with teclistamab despite previous myeloma treatment failures. Clinical Trial Registration: NCT03145181, NCT04557098 (ClinicalTrials.gov).