Phase 1b trial of isatuximab, an anti-CD38 monoclonal antibody, in combination with carfilzomib as treatment of relapsed/refractory multiple myeloma

Proteasome inhibition in combination with immunotherapies: State-of-the-Art in multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell disorder accounting for around 1.8% of all neoplastic diseases. Nowadays, clinicians have a broad arsenal of drugs at their disposal for the treatment of MM, such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, bispecific antibodies, CAR T-cell therapies and antibody-drug conjugates. In this paper we briefly highlight essential clinical elements relating to proteasome inhibitors, such as bortezomib, carfilzomib and ixazomib. Studies suggest that the early use of immunotherapy may improve outcomes significantly. Therefore, in our review we specifically focus on the combination therapy of proteasome inhibitors with novel immunotherapies and/or transplant. A high number of patients develop PI resistance. Thus, we also review new generation PIs, such as marizomib, oprozomib (ONX0912) and delanzomib (CEP-18770) and their combinations with immunotherapies.

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.

Anti CD38 monoclonal antibodies for multiple myeloma treatment

CD38 is a transmembrane glycoprotein with ectoenzymatic activity and is highly and uniformly expressed on multiple myeloma (MM) cells. CD38 is expressed also at relatively low levels on normal lymphoid and myeloid cells, and in some tissues of non-hematopoietic origin. The specificity of this target has increased interest in new drugs and triggered the development of the CD38 monoclonal antibodies Daratumumab (fully human) and Isatuximab (chimeric). CD38 antibodies have pleiotropic mechanisms of action including Fc-dependent immune effector mechanisms, direct apoptotic activity, and immunomodulatory effects by the elimination of CD38+ immune-suppressor cells. Monoclonal antibody-based therapy has revolutionized MM therapy in the latest years increasing depth of response. This product review will focus on anti-CD38 monoclonal antibodies Daratumumab and Isatuximab efficacy, safety, pharmacokinetic and pharmacodynamic data from clinical trials.

Anti-CD38 antibody therapy for patients with relapsed/refractory multiple myeloma: differential mechanisms of action and recent clinical trial outcomes

CD38 is a transmembrane glycoprotein that functions both as a receptor and an ectoenzyme, playing key roles in the regulation of calcium signaling and migration of immune cells to tumor microenvironments. High expression on multiple myeloma (MM) cells and limited expression on normal cells makes CD38 an ideal target for the treatment of MM patients. Two monoclonal antibodies directed at CD38, isatuximab and daratumumab, are available for use in patients with relapsed and/or refractory MM (RRMM); daratumumab is also approved in newly diagnosed MM and light-chain amyloidosis. Clinical experience has shown that anti-CD38 antibody therapy is transforming treatment of MM owing to its anti-myeloma efficacy and manageable safety profile. Isatuximab and daratumumab possess similarities and differences in their mechanisms of action, likely imparted by their binding to distinct, non-overlapping epitopes on the CD38 molecule. In this review, we present the mechanistic properties of these two antibodies and outline available evidence on their abilities to induce adaptive immune responses and modulate the bone marrow niche in MM. Further, we discuss differences in regulatory labeling between these two agents and analyze recent key clinical trial results, including evidence in patients with underlying renal impairment and other poor prognostic factors. Finally, we describe the limited existing evidence for the use of isatuximab or daratumumab after disease progression on prior anti-CD38 mono- or combination therapy, highlighting the need for additional clinical evaluations to define optimal anti-CD38 antibody therapy selection and sequencing in RRMM.

Isatuximab in the Treatment of Multiple Myeloma: A Review and Comparison With Daratumumab

Multiple myeloma (MM) is a hematologic malignancy characterized by the proliferation of clonal plasma cells. Although advances in treatment have markedly improved survival outcomes for patients with MM, this disease is still considered incurable owing to its high incidence of relapse and refractoriness. Isatuximab is an anti-CD38 monoclonal antibody that can induce apoptosis in myeloma cells through a variety of mechanisms. Many clinical studies have demonstrated the efficacy and efficiency of isatuximab in both relapsed/refractory multiple myeloma (RRMM) and newly diagnosed multiple myeloma, leading to its approval for the treatment of adults with RRMM in combination therapies. In this review, the structure, mechanisms of action, pharmacokinetics, pharmacogenetics, and safety profile of isatuximab in MM are summarized. Additionally, isatuximab is compared with daratumumab in terms of mechanism and efficacy.

Serum hsa_circ_0087776 as a new oncologic marker for the joint diagnosis of multiple myeloma

Multiple myeloma (MM) is a hematologic malignancy caused by abnormal proliferation of bone marrow plasma cells, which lacks diagnostic markers and has a general prognosis. At present, the understanding of its pathogenesis provides the basis for the combined diagnosis and new targeted therapy of the disease. In this study, quantitative real-time PCR was used to detect 136 MM patients and 74 healthy controls, and the clinical application value of hsa_circ_0087776 as a new tumor marker and combined diagnosis was evaluated. The results showed that the expression of hsa_circ_0087776 was significantly lower in serum of MM patients (P-value < 0.0001), and the expression was consistent in MM cells. In the analysis of clinicopathological parameters, it was found that there were significant statistical differences with MM stage and renal injury. In addition, it significantly increased the sensitivity with ALB, β₂-MG joint diagnosis, to provide a basis for diagnosis, improve the prognosis of the disease, improve the survival of patients and quality of life. These studies suggest that hsa_circ_0087776 can be used as a new oncology marker for the combined diagnosis of MM.

Impact statement: Various evidences have shown that the role of circRNA in the occurrence and development of diseases is potentially unknown and untapped. Therefore, it has a broad prospect to find circRNA specifically expressed in MM patients for combined diagnosis and targeted therapy of MM. However, MM lacks such specific tumor markers. Therefore, the discovery of new specific tumor markers for combined diagnosis is an important milestone in the development of medical history. In the research, we founded hsa_circ_0087776 can be used as a new oncology marker for combined diagnosis of MM.

Isatuximab, carfilzomib and dexamethasone (Isa-Kd) for the management of relapsed multiple myeloma

The treatment of relapsed multiple myeloma remains challenging. Based on interim data from the randomized Phase III IKEMA study demonstrating a progression-free survival benefit with a combination of isatuximab (Isa, a CD38-targeted monoclonal antibody) and carfilzomib/dexamethasone (Kd) versus Kd alone, Isa-Kd recently received regulatory approval in the USA and Europe for patients with multiple myeloma who have received at least one prior line of therapy (in the USA, up to three prior lines). In this review we discuss the rationale and clinical trial experience to date with Isa-Kd. Although final IKEMA results are pending, Isa-Kd has emerged as an effective and tolerable therapy for patients with relapsed multiple myeloma. Given the growing number of antibody-containing triplet regimens in this setting, potential niches and limitations for Isa-Kd are also discussed.

Phase 1b trial of isatuximab, an anti-CD38 monoclonal antibody, in combination with carfilzomib as treatment of relapsed/refractory multiple myeloma

Background

Isatuximab (Isa), an anti‐CD38 monoclonal antibody, and carfilzomib (K), a next‐generation proteasome inhibitor (PI), both have potent single‐agent activity in relapsed and refractory multiple myeloma (RRMM).

Methods

This phase 1b study evaluated the combination of Isa and K in 33 patients with RRMM. Isa was administered by intravenous infusion in 3 dosing cohorts: dose level 1 (Isa at 10 mg/kg biweekly), dose level 2 (DL2; Isa at 10 mg/kg weekly for 4 doses and then biweekly), and dose level 3 (Isa at 20 mg/kg weekly for 4 doses and then biweekly) and all patients received K (20 mg/m² intravenously for cycle 1, days 1 and 2, and then 27 mg/m² for all subsequent doses). A standard 3+3 dose‐escalation design was used, no dose‐limiting toxicity was observed, and the maximum tolerated dose was not reached. An expansion cohort of 18 patients was enrolled at DL2 to further evaluate safety and efficacy. Responses were assessed with the International Myeloma Working Group response criteria, and patients continued treatment until disease progression or unacceptable toxicity.

Results

With a median follow‐up of 26.7 months, in this heavily pretreated population with a median of 3 prior lines (refractory to PIs and immunomodulatory drugs, 76%; refractory to K, 27%), the overall response rate was 70% (stringent complete response/complete response, 4; very good partial response, 8; partial response, 11). The median progression‐free survival was 10.1 months, and the 2‐year survival probability was 76%. The most common treatment‐related adverse events (grade 2 or higher) were anemia, leukopenia, neutropenia, thrombocytopenia, hypertension, and infection. Infusion reactions were common (55%) but did not limit dosing.

Conclusions

Treatment with Isa plus K was well tolerated with no unexpected toxicity. The combination was effective despite the enrollment of heavily pretreated patients with RRMM.

Lay Summary

This phase 1b study was designed to assess the safety, pharmacokinetics, and preliminary efficacy of isatuximab and carfilzomib in patients with relapsed and refractory multiple myeloma.

Thirty‐three patients were treated: 15 in dose escalation and 18 in dose expansion. Patients received an average of 10 cycles.

The treatment was safe and effective. No unexpected toxicity or drug‐drug interactions were noted. Seventy percent of the subjects responded to therapy, and the progression‐free survival was 10.1 months.

The combination of isatuximab and carfilzomib is safe with low levels of grade 3/4 hematologic and nonhematologic toxicities and no unexpected drug‐drug interactions. This treatment combination appears effective with an overall response rate of 70% and progression‐free survival of 10.1 months in patients with highly refractory multiple myeloma.