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

Individualized dynamic risk assessment and treatment selection for multiple myeloma

BACKGROUND

Individualized treatment decisions for multiple myeloma (MM) patients require accurate risk stratification that accounts for patient-specific consequences of cytogenetic abnormalities on disease progression.

METHODS

Previously, SYstems Genetic Network AnaLysis (SYGNAL) of multi-omics tumor profiles from 881 MM patients generated a mmSYGNAL network of transcriptional programs underlying disease progression across MM subtypes. Here, through machine learning on activity profiles of mmSYGNAL programs we have generated a unified framework of cytogenetic subtype-specific models for individualized risk classifications and prediction of treatment response.

RESULTS

Testing on 1,367 patients across five independent cohorts demonstrated that the framework of mmSYGNAL risk models significantly outperformed cytogenetics, International Staging System, and multi-gene biomarker panels in predicting PFS at primary diagnosis, pre- and post-transplant and even after multiple relapses, making it useful for individualized risk assessment throughout the disease trajectory. Further, treatment response predictions were significantly concordant with efficacy of 67 drugs in killing myeloma cells from eight relapsed refractory patients. The model also provided new insights into matching MM patients to drugs used in standard of care, at relapse, and in clinical trials.

CONCLUSION

Activities of transcriptional programs offer significantly better prognostic and predictive assessments of treatments across different stages of MM in an individual patient.

A real-world experience of efficacy and safety of belantamab mafodotin in relapsed refractory multiple myeloma

While initial trials led to the accelerated approval of belantamab mafodotin, a BCMA-directed antibody-drug conjugate, confirmatory trials failed to establish benefit from this therapy for patients with relapsed refractory multiple myeloma (RRMM), eventually leading to its withdrawal from commercial use. With an imminent approval as an effective combination therapy, as seen in recent randomized trials, we report real-world clinical outcomes with belantamab mafodotin in 81 RRMM patients. With a median of 5 (range 2-15) prior lines of therapy, 92, 45, and 15% of the patients were triple-class refractory, penta-class refractory, and BCMA-refractory. More than half (57%) of the patients had high-risk cytogenetics, 37% had extramedullary disease (EMD), and 67% of the patients would have been considered ineligible for the DREAMM-2 trial. The best overall response (ORR) and complete response rates were 40.0 and 15.0%, respectively. ORRs were lower in patients with EMD, BCMA-refractory, and penta-refractory disease at 23, 17, and 24%, respectively. All-grade ocular toxicity was seen in 69% of patients, with grade 3+ events in 43%. Grade 3+ hematological toxicities included neutropenia (20%), anemia (28%), and thrombocytopenia (31%). With a median follow-up of 11.3 (0.3-44.6) months for the entire population, median PFS and OS were 5 (1-20) months and 12 (3-28) months, respectively. Presence of EMD was the only predictor of both PFS and OS on multivariable analysis. Compared to the pivotal trial and despite several high-risk disease features, belantamab mafodotin demonstrated comparable efficacy and safety in this real-world patient population.

Infections during novel myeloma therapies

New generation therapies such as bispecific antibodies (BsAb), chimeric antigen receptor T-cell therapy (CAR T) and antibody-drug conjugates (ADC) have revolutionized the treatment of relapsed/refractory multiple myeloma (RRMM). However, there is emerging evidence of increased infection risk associated with these treatments in clinical trials and observational settings. This infection risk may be mediated by on-target, off-tumor side effects such as cytokine release syndrome, hypogammaglobulinaemia and cytopenias, disease-related humoral impairment and the consequences of multiple previous lines of treatment. While bacterial and viral pathogens predominate, reactivation of latent infection and opportunistic infections also warrant attention. This review characterizes the epidemiology of infections associated with novel therapies for RRMM to guide prophylaxis and antimicrobial prescribing in this patient population and highlights future areas of focus to inform ongoing infection prevention strategies.

Belantamab mafodotin, lenalidomide and dexamethasone in transplant-ineligible patients with newly diagnosed multiple myeloma: part 1 results of a phase I/II study

Preclinical and clinical data demonstrate synergy between belantamab mafodotin (belamaf) and immunomodulatory drugs with limited overlapping toxicities. We investigated the safety and efficacy of belamaf with lenalidomide 25 mg on days 1-21 every 28 days and dexamethasone 40 mg weekly (belamaf-Rd) in transplant-ineligible patients with newly diagnosed multiple myeloma. Thirty-six patients (median age, 72.5 years) were randomized to receive belamaf at three different doses (2.5, 1.9, or 1.4 mg/kg) every 8 weeks. The dosing schedule was extended to every 12 weeks to mitigate ocular toxicity. Most common grade ≥3 adverse events were fatigue (n=21, 58.3%), rash (n=6, 16.7%), diarrhea (n=8, 22.2%) and COVID-19 (n=5, 13.9%). Grade 3-4 ocular adverse events, comprising visual acuity decline from baseline and/or keratopathy, were reported in 39/216 (18.1%), 33/244 (13.5%), and 26/207 (12.6%) ophthalmological assessments in the 2.5, 1.9, and 1.4 mg/kg cohorts, respectively. Importantly, grade 3-4 keratopathy was identified in 9/216 (4.2%), 1/244 (0.4%) and 1/207(0.5%) assessments. Most patients (32/36, 88.9%) were treated with the extended, every-12-week schedule, during which 40, 33 and 16 doses were withheld due to ocular adverse events in the 2.5, 1.9, and 1.4 mg/kg cohorts, respectively. Overall, the rates of very good partial response and better and complete response and better were 83.3% and 52.8%, respectively, without significant differences among cohorts. Over a median follow-up of 20.3 months no disease progression was reported; six patients discontinued treatment due to infection-related death (4 cases of COVID-19, 2 cases of pneumonia) and one patient withdrew consent. Based on the toxicity/efficacy balance, the recommended phase II dose was 1.9 mg/kg every 8 weeks, extended to every 12 weeks because of toxicity. In conclusion, Belamaf-Rd, with the extended schedule for belamaf, showed important clinical activity and a significant improvement of ocular adverse events with minimal impact on vision-related functioning in an elderly, non-transplant eligible population.

Belantamab mafodotin: an important treatment option for vulnerable patients with triple class exposed relapsed and/or refractory multiple myeloma

Not available.

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.

Characteristics of isatuximab-derived interference in serum protein electrophoresis and immunofixation, and an absence of sustained in vivo interference due to belantamab mafodotin and denosumab

OBJECTIVES

Some therapeutic monoclonal antibodies, like daratumumab and elotuzumab, produce interfering monoclonal bands on serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE). Whether other common therapeutic antibodies also produce interference has not been systematically evaluated.

DESIGN AND METHODS

SPEP/IFE from patients receiving isatuximab (48 patients), belantamab mafodotin (BM; 41), and denosumab (41) were retrospectively reviewed for therapeutic antibody interference. Cases exhibiting isatuximab interference were quantified and the maximum duration of isatuximab effect was evaluated. To characterize band position, neat human serum was spiked with BM or denosumab at supratherapeutic concentrations. Band migration patterns were compared on SPEP and IFE, with band position expressed relative to other constant protein fractions.

RESULTS

Isatuximab-induced IFE interference was common (81.3 % of evaluated patients) with a maximum observed duration of 8 weeks. 10.4 % of isatuximab patients had IgG kappa monoclonal gammopathies that co-migrated with the drug; this subset could benefit from HYDRASHIFT 2/4 isatuximab testing. 8.3 % of IFE cases were negative for an isatuximab band but showed large, endogenous M-spikes migrating elsewhere. All patients in this group expired within 1 year of this finding. We hypothesize that an inability to detect isatuximab in this setting corresponds to a large residual myeloma burden that reduces isatuximab serum concentration. This observation may serve as a negative prognostic factor. Spiking studies demonstrated that BM and denosumab produce interference in vitro, but sustained interference was not observed in >40 treated patients.

CONCLUSIONS

Therapeutic antibody interference in patients receiving isatuximab is common, and can persist for at least 8 weeks after administration. >10 % of patients receiving isatuximab may benefit from HYDRASHIFT testing post-therapy. In contrast, BM and denosumab fail to produce sustained interference in treated patients.

Treatment with low-dose, single-agent belantamab mafodotin is safe and provides long-term responses in heavily pretreated multiple myeloma patients

OBJECTIVES

To evaluate whether low-dose belantamab mafodotin (B-MAF) dosing results in lower toxicity and better overall outcome.

METHODS

We retrospectively evaluated nine consecutive patients treated with low-dose (1.9 mg/kg) B-MAF.

RESULTS

The median age was 70 years. Most patients were penta-refractory. Ocular toxicity was observed in 77.7%. Adverse events resulting in treatment delays were recorded in 9 out of 124 cycles being given. Overall response rate was 66% (6/9), and all responding patients achieved very good partial response or better. Within a median follow-up of 12 (range 0.5-13.8) months, median progression-free survival and overall survival were 14 (CI95% 6-22) and 20 (95%CI 0-41) months, respectively.

CONCLUSION

Low-dose B-MAF regimen showed high-efficacy and low-toxicity profile.