Efficacy and safety of belantamab-mafodotin in triple-refractory multiple myeloma patients: A multicentric real-life experience

Belantamab Mafodotin Monotherapy for Multiply-Relapsed Myeloma: A Retrospective Study From the United Kingdom and the Republic of Ireland

Introduction

Belantamab mafodotin (belamaf) was the first BCMA-targeting immunotherapy licensed in myeloma and was available as monotherapy for a fifth or greater line of treatment. Outcomes for patients in the United Kingdom and the Republic of Ireland potentially differ from those of other regions and may illuminate factors predicting response to therapy.

Methods and Results

We performed a retrospective study of patients treated with belamaf monotherapy in the United Kingdom and the Republic of Ireland. In our cohort of 88 patients, we saw an overall response rate (ORR) of 60%, a median progression-free survival (PFS) of 8.7 months and a median duration of response (DoR) of 15.8 months. The spectrum of adverse events was as expected, with 84% (71/85) of patients experiencing toxicity. Eye-related adverse events were the most common, affecting 66% (56/85), leading to dose reduction or delay in 41% (35/85) and discontinuation in 6% (5/85). We specifically assessed physician decision-making in the context of ocular side effects and found a relatively high frequency of the drug being administered despite moderate levels of toxicity.

Conclusion

Our cohort's ORR is significantly different from those of the DREAMM-2 and -3 trials and other real-world studies, though a long-duration response has been reported in other cohorts. Comparative analysis with other real-world studies did not reveal any significant factors predictive of ORR. The frequent administration of belamaf to patients with eye disease may well reflect a more pragmatic approach than was originally prescribed in the landmark trials.

Trial Registration

The authors have confirmed clinical trial registration is not needed for this submission.

Treatment Patterns, Efficacy, and Tolerability of Belantamab Mafodotin in Patients With Relapsed and/or Refractory Multiple Myeloma: A Real-World Analysis

PURPOSE

Belantamab mafodotin is an anti-B cell maturation antigen (BCMA) immunoconjugate for patients with relapsed/refractory multiple myeloma (RRMM). Additional data on its treatment patterns, efficacy, and tolerability in real-world settings are needed.

PATIENTS AND METHODS

This single-site, retrospective study examined 30 adults with multiple myeloma receiving care at Duke Cancer Institute who began belantamab mafodotin monotherapy between 8/5/2020 and 11/22/2022. We described baseline clinical characteristics, disease response (per International Myeloma Working Group [IMWG] criteria, as possible given available bone marrow biopsy data), belantamab mafodotin treatment patterns, and ocular adverse events (per the Keratopathy Visual Acuity [KVA] scale).

RESULTS

Across 30 patients, the median number of lines of therapy was 4, 20 patients (87%) were triple-/quad-/penta-refractory, and 7 (23%) had high-risk cytogenetics (per IMWG criteria). Overall response rate was 67%. Progression occurred in 22 patients (73%); median progression-free survival was 9.5 months (95% CI 6.6-15.6). Median overall survival was not reached as of 3-year follow-up. Dose reduction occurred in 19 patients (63%); 65% were due to ocular adverse events, 30% hematologic adverse events. Cycle delay occurred in 28 (93%); 85% were due to ocular adverse events. Keratopathy (any grade) occurred in 28 (93%); 2% of events were grade ≥3. Visual acuity change (any grade) occurred in 27 (90%); 3.3% of events were grade ≥3. Treatment discontinuation from ocular toxicity occurred in 4 (13%).

CONCLUSION

Despite a high incidence of manageable keratopathy, these data demonstrate benefit in belantamab mafodotin in patients with RRMM over an extended time amid dose/cycle modifications.

REGISTRATION

CLINICALTRIALS.GOV: NCT05986682.

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.

Belantamab mafodotin in triple-refractory multiple myeloma patients: A retro-prospective observational study in Italy

Belantamab mafodotin is the first-in-class antibody-drug conjugates targeting B-cell maturation antigen to have demonstrated effectiveness in triple-class refractory multiple myeloma (TCR-MM) patients. We performed a retrospective study including 78 TCR patients, with at least four prior lines of therapy (LOTs), who received belantamab mafodotin within named patient program and expanded access program in Italy between 2020 and 2022. Median age was 65 years (range 42-86 years), ECOG performance status was ≥1 in 45% of patients. Overall, a clinical benefit was obtained in 36 out of 74 evaluable patients (49%), with 43%, 28%, and 13.5% achieving at least partial response, very good partial response, and complete response, respectively. After a median follow-up of 12 months (range 6-21 months), median duration of response, progression-free survival (PFS), and overall survival (OS) were 14, 5.5, and 12 months, respectively. Age >70 years, good performance status and response were associated with longer PFS and OS. Keratopathy occurred in 58% of patients (G3 2.5%), corneal symptoms in 32% (G3 1.2%) and a reduction in visual acuity in 14%. Grade 3 thrombocytopenia occurred in 9% of patients. Only 3% of patients discontinued belantamab mafodotin because of side effects. This real-life study demonstrated significant and durable responses of belantamab in TCR-MM patients with four prior LOTs, otherwise ineligible for novel immunotherapies.

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.

Plasma levels of BCMA-positive extracellular vesicles correlate to response and side effects in myeloma patients treated with belantamab-mafodotin

In myeloma patients, high levels of soluble BCMA (sBCMA) can limit the efficacy of BCMA-directed therapies. Belantamab-mafodotin is a BCMA antibody-drug conjugate and shows good overall response rates in heavily pretreated patients but progression-free survival data are poor. As the drug induces apoptosis, we hypothesized that sBCMA includes extracellular vesicles (EV) and thus evaluated numbers of BCMA-EV before and during belantamab therapy in 10 myeloma patients. BCMA-EV were significantly higher in patients prior to Belantamab (median: 3227/μl; p = .013) than in other myeloma patients before therapy (n = 10; 1082/μl) or healthy volunteers (n = 10; 980/μl). During therapy, BCMA-EV showed a significant increase to a maximum of 8292/μl (p = .028). Maximal changes in BCMA-EV (Δmax = BCMA-EV at C1/maximal BCMA-EV) showed a strong inverse, logarithmic correlation (r = -.950; p < .001) with FLC ratio changes (Δmax = FLC ratio at C1/minimal FLC ratio) and BCMA-EV peaks often preceded FLC progression. Correlating increase of LDH and BCMA-EV levels, together with clinical symptoms, point to a mafodotin-induced eryptosis. In summary, BCMA-EV are a part of sBCMA, peak levels precede progression, and their measurement might be helpful in identifying resistance mechanisms and side effects of BCMA targeted therapies.

Safety of Subcutaneous Daratumumab in Anti-CD38 Monoclonal Antibody-Naïve Patients with Plasma Cell Disorders: A Multicenter Real-Life Experience

BACKGROUND

Daratumumab, an anti-CD38 monoclonal antibody, is used for treatment of multiple myeloma (MM) and light chain amyloidosis at an intravenous dosage of 16 mg/kg or at a subcutaneous fixed dose of 1800 mg. However, the subcutaneous formulation has only recently been approved in Europe, and real-life data on its safety are still few.

OBJECTIVE

In this multicenter retrospective real-life experience, we provided evidence for the safety of subcutaneous daratumumab in plasma cell disorders.

PATIENTS AND METHODS

A total of 189 patients diagnosed with MM or light chain amyloidosis were included in this retrospective study, and all subjects were daratumumab-naïve. Primary endpoint was safety of subcutaneous daratumumab, especially for infusion-related reaction (IRR) incidence and severity. All patients received premedication with dexamethasone, paracetamol, and antihistamine, with montelukast usage in 85% of cases.

RESULTS

Eight patients (4%) experienced IRRs, mainly of grade I-II, and other frequent toxicities were: hematological (thrombocytopenia, 4%; neutropenia, 5%; lymphopenia, 6%) and non-hematological (pneumonia, 4%; diarrhea, 2%; and cytomegalovirus reactivation, 0.5%). In our multicenter retrospective real-life experience, subcutaneous daratumumab was well-tolerated with an excellent safety profile with a very low (4%) IRR incidence, even in frailer MM patients with severe renal impairment or increased body weight.

CONCLUSIONS

Subcutaneous daratumumab was safe in a real-life setting including patients with severe renal failure and advanced disease. However, further studies on larger and prospective cohorts are required to confirm our real-life observations.

Recommendations for Management of Secondary Antibody Deficiency in Multiple Myeloma

Secondary antibody deficiency (SAD) is a subtype of secondary immunodeficiency characterized by low serum antibody concentrations (hypogammaglobulinemia) or poor antibody function. SAD is common in patients with multiple myeloma (MM) due to underlying disease pathophysiology and treatment-related immune system effects. Patients with SAD are more susceptible to infections and infection-related morbidity and mortality. With therapeutic advancements improving MM disease control and survival, it is increasingly important to recognize and treat the often-overlooked concurrent immunodeficiency present in patients with MM. The aims of this review are to define SAD and its consequences in MM, increase SAD awareness, and provide recommendations for SAD management. Based on expert panel discussions at a standalone meeting and supportive literature, several recommendations were made. Firstly, all patients with MM should be suspected to have SAD regardless of serum antibody concentrations. Patients should be evaluated for immunodeficiency at MM diagnosis and stratified into management categories based on their individualized risk of SAD and infection. Infection-prevention strategy education, early infection reporting, and anti-infective prophylaxis are key. We recommend prophylactic antibiotics or immunoglobulin replacement therapy (IgRT) should be considered in patients with severe hypogammaglobulinemia associated with a recurrent or persistent infection. To ensure an individualized and efficient treatment approach is utilized, patient's immunoglobin G concentration and infection burden should be closely monitored throughout treatment. Patient choice regarding route and IgRT treatment is also key in reducing treatment burden. Together, these recommendations and proposed management algorithms can be used to aid physician decision-making to improve patient outcomes.

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.

A safety review of recently approved and emerging drugs for patients with relapsed or refractory multiple myeloma

INTRODUCTION

Multiple new drugs have been approved over the past 5 years for the treatment of relapsed/refractory multiple myeloma (RRMM), and these are being increasingly widely used. Clinicians need to familiarize themselves with common toxicities associated with these drugs and with novel toxicities requiring specific management and supportive care.

AREAS COVERED

We review common toxicities associated with agents approved for RRMM in the past 5 years, including the anti-CD38 monoclonal antibody isatuximab, the antibody-drug conjugate belantamab mafodotin, the bispecific antibody teclistamab, the chimeric antigen receptor (CAR) T cell products idecabtagene vicleucel and ciltacabtagene autoleucel, the selective inhibitor of nuclear export compound selinexor, and the drug-peptide conjugate melflufen, as well as toxicities associated with emerging agents for RRMM including additional bispecific antibodies, the BCL-2 inhibitor venetoclax, and the cereblon E3 ligase modulators iberdomide and mezigdomide. We searched the published literature using PubMed, plus congress abstracts, for the above list of drug names or classes and 'myeloma.'

EXPERT OPINION

Optimal management of toxicities associated with these recently approved and emerging therapies will be critical in maximizing clinical benefit and aiding widespread adoption in routine clinical practice. We summarize current recommendations and guidelines and provide expert insights into supportive care requirements.

Belantamab Mafodotin in Patients with Relapsed/Refractory Multiple Myeloma: Results of the Compassionate Use or the Expanded Access Program in Spain

Belantamab-mafodotin (belamaf) is a novel antibody-drug conjugate targeting B-cell maturation antigen that showed anti-myeloma activity in patients with relapsed and refractory multiple myeloma (RRMM). We performed an observational, retrospective, and multicenter study aimed to assess the efficacy and safety of single-agent belamaf in 156 Spanish patients with RRMM. The median number of prior therapy lines was 5 (range, 1-10), and 88% of patients were triple-class refractory. Median follow-up was 10.9 months (range, 1-28.6). The overall response rate was 41.8% (≥CR 13.5%, VGPR 9%, PR 17.3%, MR 2%). The median progression-free survival was 3.61 months (95% CI, 2.1-5.1) and 14.47 months (95% CI, 7.91-21.04) in patients achieving at least MR (p < 0.001). Median overall survival in the entire cohort and in patients with MR or better was 11.05 months (95% CI, 8.7-13.3) and 23.35 (NA-NA) months, respectively (p < 0.001). Corneal events (87.9%; grade ≥ 3, 33.7%) were the most commonly adverse events, while thrombocytopenia and infections occurred in 15.4% and 15% of patients, respectively. Two (1.3%) patients discontinued treatment permanently due to ocular toxicity. Belamaf showed a noticeably anti-myeloma activity in this real-life series of patients, particularly among those achieving MR or better. The safety profile was manageable and consistent with prior studies.

Belantamab Mafodotin: From Clinical Trials Data to Real-Life Experiences

Despite the recent approval of novel immunotherapies, such as immunomodulatory drugs, proteasome inhibitors and anti-CD38 monoclonal antibodies, Multiple Myeloma (MM) remains incurable, and the acquisition of triple-refractoriness leads to really dismal outcomes in even earlier lines of therapy. More recently, innovative therapeutic strategies targeting B cell maturation antigen (BCMA), highly expressed on the plasma cell surface, are drawing different future landscapes in terms of effectiveness and outcomes. Belantamab Mafodotin, a first-in-class anti-BCMA antibody-drug conjugate, demonstrated good efficacy and safety profile in triple-refractory patients in the phase 2 DREAMM-2 trial, and it was approved for the treatment of MM triple-exposed patients with >4 prior lines of therapy. Here, starting from Belantamab Mafodotin clinical trials and also exploring combination studies and different schedules in order to improve its efficacy and toxicity, we focused on real-life experiences all over the world, which have confirmed clinical trial data and encourage further Belantamab Mafodotin investigations.

Outcomes of Penta-Refractory Multiple Myeloma Patients Treated with or without BCMA-Directed Therapy

Despite advances in treatment, outcomes remain poor for patients with penta-relapsed refractory multiple myeloma (RRMM). In this retrospective analysis, we evaluated the survival outcomes of penta-RRMM patients treated with (BCMA)- directed therapy (BDT). We identified 78 patients with penta-RRMM. Median age was 65 years, 29 (37%) had R-ISS stage III disease, 63 (81%) had high-risk cytogenetics, and 45 (58%) had extra-medullary disease. Median LOT prior to penta-refractory state was 5 (3-12). Amongst penta-RRMM, 43 (55%) were treated with BDT, 35 (45%) were not treated with BDT. Type of BDT received included belantamab mafadotin 15 (35%), Chimeric Antigen Receptor T-cell therapy 9 (21%), BCMA monoclonal antibody 6 (14%), and Bispecific T-cell engager 2 (5%). Eleven (25%) patients received more than one BDT. No significant differences were identified between baseline characteristics for the two groups. Patients treated with a BDT had better median overall survival, 17 vs. 6 months, HR 0.3 p-value < 0.001. Poor performance status, white race, and high-risk cytogenetics were associated with worse outcomes, whereas using a BDT was associated with better outcomes. Patients with penta-refractory MM have poor outcomes. Our retrospective analysis showed a significant survival benefit using BDT when compared to non-BDT for patients with penta-RRMM.

Real-World Outcomes of Belantamab Mafodotin for Relapsed/Refractory Multiple Myeloma (RRMM): Preliminary Results of a Spanish Expanded Access Program (EAP)

INTRODUCTION

Belantamab mafodotin (BM) is a new anti-BCMA antibody-drug conjugate, recently approved for triple-class relapsed and refractory multiple myeloma (RRMM). We assessed real-world outcomes with BM in patients under the Spanish Expanded Access Program (EAP).

METHODS

We conducted an observational, retrospective, multicenter study including RRMM patients who received ≥ 1 dose of BM (Nov 2019 to Jun 2021). The primary endpoint was overall response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and incidence of treatment-emergent adverse events (TEAEs).

RESULTS

Thirty-three patients were included with a median of 70 years of age (range, 46-79 years). Median time from diagnosis was 71 months (range, 10-858 months). Median prior lines was 5 (range, 3-8 lines); 90% of patients were triple-/quad-/penta-refractory; 48% showed high-risk cytogenetics. Median BM doses was 3 (range 1-16 doses), with a median follow-up of 11 months (6-15 months). ORR was 42.2% (≥ VGPR, 18.2%). Median PFS was 3 months (95% CI 0.92-5.08) in the overall population, and 11 months (HR 0.26; 95% CI 0.10-0.68) for patients who achieved ≥ PR. PFS was not significantly different according to age, cytogenetic risk, and prior therapy lines. OS was 424 days (95% CI 107-740). Non-hematological TEAEs (57.6% of patients; 30.3% ≥ G3) included keratopathy (51.5%; 21.2% ≥ G3) and patient-reported vision-related symptoms (45.5%). Keratopathy was resolved in 70.6% of patients. G3 hematological TEAEs was 18.2%, thrombocytopenia (21.2%). Dose reductions due to TEAEs: 30.3%; delays: 36.4%. Treatment discontinuation causes: progression (54.5%), toxicity (non-ocular; 6%/ocular; 6% /ocular + non-ocular toxicity; 3%), death (6%), and patient's decision (3%).

CONCLUSIONS

BM showed relevant anti-myeloma activity in RRMM with a manageable safety profile. These results corroborate those observed in the BM pivotal trial.