Safety and efficacy of belantamab mafodotin with pembrolizumab in patients with relapsed or refractory multiple myeloma.

BACKGROUND: Belantamab mafodotin (belamaf) has shown promising antimyeloma activity in relapsed or refractory multiple myeloma (RRMM) as a single agent. It was hypothesized that its multimodal activity may be enhanced by programmed cell death protein 1 pathway inhibition and activation of T cell-mediated antitumor responses. This study investigated the efficacy and safety of belamaf with pembrolizumab in patients with RRMM. METHODS: DREAMM-4 (NCT03848845) was an open-label, single-arm, phase 1/2 study divided into dose-escalation (part 1) and dose-expansion (part 2) phases. Patients were ≥18 years old with ≥3 prior lines of therapy including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 agent. Patients received belamaf (2.5 or 3.4 mg/kg, part 1; 2.5 mg/kg, part 2) and 200 mg pembrolizumab for ≤35 cycles. RESULTS: Of 41 enrolled patients, 34 (n = 6 part 1, n = 28 part 2) who received 2.5 mg/kg belamaf plus pembrolizumab were included in this final analysis. Sixteen patients (47%) achieved an overall response. Minimal residual disease negativity was achieved in three of 10 patients who had very good partial response or better. Five of eight patients who had prior anti-B-cell maturation antigen therapy achieved partial response or better, including two who had B-cell maturation antigen-refractory disease. Common grade ≥3 adverse events were keratopathy (38%) and thrombocytopenia (29%). Despite belamaf-related ocular events, quality-of-life measures remained stable over time. No new safety signals were observed. CONCLUSIONS: The results of DREAMM-4 demonstrated clinical activity and a favorable safety profile of belamaf plus pembrolizumab in patients with RRMM. This trial is registered at www. CLINICALTRIALS: gov as NCT03848845.

Effectiveness and safety of belantamab mafodotin in patients with relapsed or refractory multiple myeloma in real-world setting: The ALFA study.

OBJECTIVES: The aim of this noninterventional, retrospective ALFA study was to describe belantamab mafodotin effectiveness and safety in patients with relapsed/refractory multiple myeloma in a real-world setting in France. METHODS: Response rate, progression-free survival (PFS), overall survival (OS), and safety were assessed. RESULTS: Among the 184 patients initiating belantamab mafodotin treatment, the overall response rate was 32.7% (≥very good partial response [VGPR] 20.4%, partial response [PR] 12.3%). The median PFS (mPFS) was 2.4 months (95% confidence interval [CI]: 1.9, 3.3), and median OS (mOS) was 8.8 months (95% CI: 6.3, 11.6). According to best response, mPFS was 20.6 months (95% CI: 12.1, not reached [NR]) in patients with ≥VGPR and 7.1 months (95% CI: 4.6, 9.4) in patients with PR; mOS was NR in patients with ≥VGPR and 17.5 months (95% CI: 7.7, NR) in patients with PR. For both OS and PFS, no differences were found in subgroups of interest. The adverse events (AEs) reported in 159 patients (86.4%) were mostly ocular AEs. CONCLUSIONS: ALFA, the largest real-world cohort conducted so far, confirms the results of belantamab mafodotin as reported in the DREAMM-2 clinical trial. The clinical benefit is significant as long as the patient is a responder.

Real-World Effectiveness and Safety of Belantamab Mafodotin Monotherapy in Triple-Class Refractory Multiple Myeloma.

B-cell maturation antigen (BCMA) is a promising therapeutic target for multiple myeloma (MM). The aim of this study was to assess the effectiveness and tolerability of monotherapy with the conjugated anti-BCMA monoclonal antibody belantamab mafodotin in triple-class refractory patients with MM in real-world practice. Patients refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 monoclonal antibody received belantamab mafodotin at 2.5 mg/kg intravenously every 3 weeks. Overall, 27 patients with a median age of 65 years (range 41-81) were included. Of these, 52% were male and the median number of prior lines of treatment was 5 (4-10). The overall response rate (partial response or better) was 52%, whereas the disease control rate (stable disease or better) was 70%. The median progression-free survival (PFS) was 2 months (95%CI: 0-7), whereas the median PFS among the responders was 12 months (95%CI: 6-18). Regarding the toxicity profile, the most common toxicity was eye toxicity, in 44% of the patients. Keratopathy grade 2-3 was reported in 33.3% of the patients. In conclusion, belantamab mafodotin showed a safety and efficacy profile consistent with the results of the registrational study. Importantly, heavily pretreated patients who responded to treatment derived a substantial survival benefit.

The Effect of Belantamab Mafodotin on Primary Myeloma-Stroma Co-Cultures: Asymmetrical Mitochondrial Transfer between Myeloma Cells and Autologous Bone Marrow Stromal Cells.

Belantamab mafodotin (belamaf) is an afucosylated monoclonal antibody conjugated to the microtubule disrupter monomethyl auristatin-F (MMAF) that targets B cell maturation antigen (BCMA) on the surface of malignant plasma cells. Belamaf can eliminate myeloma cells (MMs) through several mechanisms. On the one hand, in addition to inhibiting BCMA-receptor signaling and cell survival, intracellularly released MMAF disrupts tubulin polymerization and causes cell cycle arrest. On the other hand, belamaf induces effector cell-mediated tumor cell lysis via antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis. In our in vitro co-culture model, the consequences of the first mentioned mechanism can be investigated: belamaf binds to BCMA, reduces the proliferation and survival of MMs, and then enters the lysosomes of malignant cells, where MMAF is released. The MMAF payload causes a cell cycle arrest at the DNA damage checkpoint between the G2 and M phases, resulting in caspase-3-dependent apoptosis. Here, we show that primary MMs isolated from different patients can vary widely in terms of BCMA expression level, and inadequate expression is associated with extremely high resistance to belamaf according to our cytotoxicity assay. We also reveal that primary MMs respond to increasing concentrations of belamaf by enhancing the incorporation of mitochondria from autologous bone marrow stromal cells (BM-MSCs), and as a consequence, MMs become more resistant to belamaf in this way, which is similar to other medications we have analyzed previously in this regard, such as proteasome inhibitor carfilzomib or the BCL-2 inhibitor venetoclax. The remarkable resistance against belamaf observed in the case of certain primary myeloma cell cultures is a cause for concern and points towards the use of combination therapies to overcome the risk of antigen escape.

The emergence of b-cell maturation antigen (BCMA) targeting immunotherapy in multiple myeloma.

OBJECTIVE: Multiple myeloma, a plasma cell neoplasm is the second most common hematological malignancy in the United States. Despite significant advances in treatment armamentarium over the last decade, multiple myeloma remains an incurable malignancy. B-cell maturation antigen (BCMA) is an antigen expressed on the surface on plasma cells that can be targeted by novel mechanisms of action including antibody-drug conjugates (ADCs), bispecific T-cell engagers, and chimeric antigen receptor (CAR) T-cell therapy. This review summarizes the clinical application and development of approved and investigational immunotherapies targeting BCMA. DATA SOURCES: A search of the PubMed database was conducted using the following search terms: BCMA, CAR T, myeloma, belantamab mafodotin, and bispecific. Ongoing clinical trials, as well as abstracts from ASH and ASCO evaluating the efficacy and safety of novel agents targeting BCMA were evaluated. Prescribing information was also reviewed. DATA SUMMARY: Since the discovery of BCMA as a target for myeloma, researchers have developed antibody-drug conjugates, bispecific T-cell engagers, and CAR T-cell therapies as novel treatment modalities for myeloma patients. Belantamab mafodotin and idecabtagene vicleucel represent currently available therapies and ongoing trials have demonstrated the efficacy and safety of bispecifics and other BCMA targeting therapies. CONCLUSION: BCMA targeting antibody drug conjugates, bispecific T-cell engagers, and CAR T-cell therapies have demonstrated clinical activity in myeloma patients and represent novel therapies in multiple myeloma treatment paradigm.

Belantamab mafodotin for relapsed or refractory multiple myeloma.

Objective: Refractory multiple myeloma (MM) presents poor responses to therapies. New drugs for highly pretreated MM are a hope for this clinical context with limited treatment options. We developed a comparative commentary on the evidence about the use of belantamab mafodotin in heavily pretreated relapsed or refractory MM with respect to other therapies. Data sources: Regimen data were extracted from pivotal clinical trials. Data summary: Response rates were the main efficacy outcomes reported in trials. Overall response was achieved by approximately 30% of patients trated with belantamab mafodotin. Response rates of different regimens must be supported by more relevant data, such as overall survival or progression-free survival. Subgroups of patients with extramedullary disease and revised International Staging System III should be thoroughly evaluated in phase III comparative clinical trials with larger sample sizes. Belantamab mafodotin presented specific adverse events (visual disturbances and kerathopathies). Grade 3-4 adverse events involved high percentages of patients treated with the different schemes. The budgetary impact of different treatments for heavily pretreated refractory MM would be very high. Literature suggested increased efficiency of belantamab mafodotin versus chimeric antigen receptor T-cell therapies. Conclusions: Belantamab mafodotin and other regimens are promising drugs for MM, especially for triple-class refractory patients. Comparative studies are necessary to perform a reliable therapeutic positioning.

Focus on monoclonal antibodies targeting B-cell maturation antigen (BCMA) in multiple myeloma: update 2021.

Remarkable advances have been achieved in the treatment of multiple myeloma (MM) in the last decade, which saw targeted immunotherapy, represented by anti-CD38 monoclonal antibodies, successfully incorporated across indications. However, myeloma is still considered curable in only a small subset of patients, and the majority of them eventually relapse. B-cell maturation antigen (BCMA) is expressed exclusively in mature B lymphocytes and plasma cells, and represents an ideal new target for immunotherapy, presented by bispecific antibody (bsAb) constructs, antibody-drug conjugates (ADCs) and chimeric antigen receptor T (CAR-T) cells. Each of them has proved its efficacy with the potential for deep and long-lasting responses as a single agent therapy in heavily pretreated patients. As a result, belantamab mafodotin was approved by the United States Food and Drug Administration for the treatment of relapsed/refractory MM, as the first anti-BCMA agent. In the present review, we focus on monoclonal antibodies targeting BCMA - bsAbs and ADCs. The data from preclinical studies as well as first-in-human clinical trials will be reviewed, together with the coverage of their constructs and mechanisms of action. The present results have laid the groundwork for the ongoing or upcoming clinical trials with combinatory regimens, which have always been a cornerstone in the treatment of MM.

EMA Review of Belantamab Mafodotin (Blenrep) for the Treatment of Adult Patients with Relapsed/Refractory Multiple Myeloma.

On August 25, 2020, a marketing authorization valid through the European Union was issued for belantamab mafodotin monotherapy for the treatment of multiple myeloma (MM) in adult patients who have received at least four prior therapies, whose disease is refractory to at least one proteasome inhibitor (PI), one immunomodulatory agent (IMiD), and an anti-CD38 monoclonal antibody (mAb), and who have demonstrated disease progression on the last therapy. Belantamab mafodotin is an antibody-drug conjugate that combines a mAb, which binds specifically to B-cell maturation antigen, with maleimidocaproyl monomethyl auristatin F, which is a cytotoxic agent. It was evaluated in Study 205678 (DREAMM-2), an open-label, two arm, phase II, multicenter study in patients with MM who had relapsed following treatment with at least three prior therapies, who were refractory to an IMiD, a PI, and an anti-CD38 mAb alone or in combination. Patients were randomized to receive 2.5 mg/kg (n = 97) or 3.4 mg/kg (n = 99) belantamab mafodotin by intravenous infusion every 3 weeks until disease progression or unacceptable toxicity. Belantamab mafodotin achieved an overall response rate (ORR) of 32% (97.5% confidence interval [CI]: 22-44) with a median duration of response (DoR) of 11 months (95% CI: 4.2 to not reached). The most frequently (≥20%) reported adverse reactions grades 3-4 with belantamab mafodotin were keratopathy (31%), thrombocytopenia (22%), and anemia (21%). With regard to the corneal risks associated with belantamab mafodotin, patients would need to undergo specific ophthalmic examinations so that any findings can be promptly and adequately managed. The scientific review concluded that a 32% ORR and a median DoR of 11 months observed with belantamab mafodotin was considered clinically meaningful. Given the manageable toxicity profile and considering that belantamab mafodotin has a mechanism of action that is different from that of authorized treatments in this group of highly pretreated patients whose disease is refractory to three classes of agents, the benefit risk for belantamab mafodotin monotherapy was considered positive, although the efficacy and safety evidence were not as comprehensive as normally required. IMPLICATIONS FOR PRACTICE: Belantamab mafodotin (Blenrep, GlaxoSmithKline, St. Louis, MO, U.S.A) was approved in the European Union as monotherapy for the treatment of adult patients with refractory/relapsed multiple myeloma. Belantamab mafodotin resulted in durable response in highly pretreated patients whose disease is refractory to three classes of agents. Belantamab mafodotin is a monoclonal antibody against B-cell maturation antigen conjugated with the potent antimitotic agent maleimidocaproyl monomethyl auristatin. This is the first monoclonal antibody to target this antigen in multiple myeloma, which represents a true novelty from a pharmacological point of view.

Belantamab mafodotin in combination with novel agents in relapsed/refractory multiple myeloma: DREAMM-5 study design.

Belantamab mafodotin (belamaf) is a BCMA-targeted antibody-drug conjugate recently approved as monotherapy for adults with relapsed/refractory multiple myeloma who have received ≥4 prior therapies. Belamaf binds to BCMA and eliminates myeloma cells by multimodal mechanisms of action. The cytotoxic and potential immunomodulatory properties of belamaf have led to novel combination studies with other anticancer therapies. Here, we describe the rationale and design of DREAMM-5, an ongoing Phase I/II platform study evaluating the safety and efficacy of belamaf combined with novel agents, including GSK3174998 (OX40 agonist), feladilimab (an ICOS; GSK3359609), nirogacestat (a gamma-secretase inhibitor; PF-03084014) and dostarlimab (a PD-1 blocker) versus belamaf monotherapy for patients with relapsed/refractory multiple myeloma. Clinical trial registration: NCT04126200 (ClinicalTrials.gov).

Updates in the management of relapsed/refractory multiple myeloma.

Multiple myeloma, a malignant neoplasm of plasma cells that accumulate in bone marrow, accounts for approximately 18% of hematologic malignancies in the United States. Patients are often treated with triplet therapy and may undergo stem cell transplantation. Despite effective therapies, multiple myeloma remains incurable. Patients often require maintenance therapy, and many will progress or relapsed following upfront treatment. Selection of treatment in the relapse/refractory setting is complex due numerous active therapeutic agents and combinations. Treatment is often tailored to prior exposure and duration. In 2020, three novel pharmacological agents were approved in the relapsed setting. We highlight the clinical safety and efficacy of selinexor, isatuximab-irfc, and belantamab mafodotin for patients with multiple myeloma.