A review discussing elotuzumab and its use in the second-line plus treatment of multiple myeloma

An update on novel multiple myeloma targets

Introduction: despite therapeutic progress, leading to a significant improvement of outcome, multiple myeloma (MM) remains a difficult to treat hematologic disease due to its biological heterogeneity and clinical complexity.

Areas covered: Treatment of patients refractory and resistant to all classes of agents used in newly diagnosed MM, is becoming a relevant problem for every hematologist. New generation immunotherapies, such as conjugated mAb, bispecific mAbs and CAR-T cells, targeting novel molecules as BCMA, have showed relevant results in very advanced MM. In the same setting, small molecules, such as selinexor and melflufen, also proved to be effective. We are currently waiting for the results of under evaluation personalized therapy, directed against specific gene mutations or signaling pathways, responsible for disease progression.

Expert Opinion: In the near future, many therapeutic strategies will become available for MM and the challenge will be to position each approach in order to cure, maintaining a good quality of life in these patients.

Belantamab Mafodotin for the Treatment of Multiple Myeloma: An Overview of the Clinical Efficacy and Safety

Despite the introduction of immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and, more recently, monoclonal antibodies (mAbs), in the chemotherapy regimens for newly diagnosed (NDMM) and relapsed/refractory MM (RRMM), the occurrence of drug resistance remains a challenge in MM patients. This is mainly in the advanced stage of the disease when treatments are limited, and the prognosis is abysmal. Nevertheless, novel molecules and therapeutic approaches are rapidly moving through the several phases of drug development and could address the need for new treatment options. The recent innovative B-cell maturation antigen (BCMA) targeted immunotherapies, such as belantamab mafodotin, the first-in-class monoclonal antibody-drug conjugate (ADC), induce an effective and durable response in triple-class refractory disease and to be approved in MM. In contrast with the other BCMA-targeted therapies as CAR T cells with a complex manufacturing process, and bispecific antibodies, both requiring inpatient hospitalization to monitor the occurrence of severe adverse events, belantamab mafodotin is an “off-the-shelf” drug that can be administered in an outpatient setting. Many belantamab mafodotin-based combinations are under evaluation in Phase I, II, and III clinical trials either late or in early RRMM patients. Ocular toxicity represents a peculiar side effect of belantamab mafodotin. This toxicity is generally manageable with adequate dose reductions or delays since most patients who developed keratopathy recovered on treatment and discontinued ADC are rare. Here, we described the most recent clinical data of belantamab mafodotin and discussed the possible leading role of this intriguing agent in the near future of MM treatment.

Novel Experimental Drugs for Treatment of Multiple Myeloma

Multiple myeloma (MM) is the second most frequent hematological malignancy characterized by bone marrow aberrant plasma cells proliferation leading to a genetic complex and heterogeneous disease, with a median survival ranging from two to more than 10 years. By using new drugs such as proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), monoclonal antibodies (mAbs) in different combinations and high-dose therapy followed by auto-transplantation, there has been an amazing improvement in the outcome of this disease in recent years. Despite this, MM is still considered an incurable disease, characterized by remission periods alternated with relapse/progression episodes finally leading to resistant disease. In particular, patients who become refractory to PIs, IMiDs and mAbs have a very poor outcome. Moreover, to overcome resistant residual disease, a large combination of drugs will be increasingly used in early lines of therapy; this further reduces the therapeutic options at each relapse. This natural history means that MM always needs new drugs/strategies to overcome the incoming resistance. New combinations of naked mAbs are becoming the therapy of choice for patients refractory to lenalidomide and/or PI; conjugated mAbs will be useful in triple- and more-refractory patients; CAR-T cells and bispecific mAbs have shown relevant results in very advanced stages of disease. In this review, we reported the results of these new therapies and explored their potential applications. Personalized and precision medicine seem to be the new frontier of cancer treatment. Although no single or few factors have been identified as disease drivers in MM, recurrent gene mutations were recognized and specific compounds targeting these alterations were developed and studied. Therefore, we reviewed these targeted drugs to try to understand what the best therapeutic strategy in MM is.

A novel BCMA PBD-ADC with ATM/ATR/WEE1 inhibitors or bortezomib induce synergistic lethality in multiple myeloma

To target mechanisms critical for multiple myeloma (MM) plasma cell adaptations to genomic instabilities and further sustain MM cell killing, we here specifically trigger DNA damage response (DDR) in MM cells by a novel BCMA antibody-drug conjugate (ADC) delivering the DNA cross-linking PBD dimer tesirine, MEDI2228. MEDI2228, more effectively than its anti-tubulin MMAF-ADC homolog, induces cytotoxicity against MM cells regardless of drug resistance, BCMA levels, p53 status, and the protection conferred by bone marrow stromal cells and IL-6. Distinctly, prior to apoptosis, MEDI2228 activates DDRs in MM cells via phosphorylation of ATM/ATR kinases, CHK1/2, CDK1/2, and H2AX, associated with expression of DDR-related genes. Significantly, MEDI2228 synergizes with DDR inhibitors (DDRi s) targeting ATM/ATR/WEE1 checkpoints to induce MM cell lethality. Moreover, suboptimal doses of MEDI2228 and bortezomib (btz) synergistically trigger apoptosis of even drug-resistant MM cells partly via modulation of RAD51 and accumulation of impaired DNA. Such combination further induces superior in vivo efficacy than monotherapy via increased nuclear γH2AX-expressing foci, irreversible DNA damages,  and tumor cell death, leading to significantly prolonged host survival. These results indicate leveraging MEDI2228 with DDRi s or btz as novel combination strategies, further supporting ongoing clinical development of MEDI2228 in patients with relapsed and refractory MM.