Clinical effects of CD33 and MPC-1 on the prognosis of multiple myeloma treated with bortezomib

Assessment of algorithms for identifying patients with triple-class refractory multiple myeloma using real-world data

Objective: Patients with triple-class refractory (TCR) multiple myeloma (MM) have limited treatment options and poor prognoses. This high unmet need has prompted the development of new therapies allowing for improved outcomes for these patients. Recently, new targeted therapies for the treatment of patients with relapsed or refractory MM have been approved based on single-arm clinical trial results. Real-world (RW) data enable a better understanding of the effectiveness of new therapies in clinical practice and provide external controls for single-arm studies. However, using RW data to identify patients with TCR MM is challenging and subject to limitations. Methods: In this retrospective cohort study of an analysis of the COTA electronic health record (EHR) database, we used four algorithms to define refractory status and created four groups of patients with TCR MM initiating post-TCR therapy. Each algorithm relied on slightly different criteria to identify TCR patients, but all were based on the International Myeloma Working Group (IMWG)-derived and/or healthcare provider (HCP)-reported progressions within the database. Results: A total of 3815 patients with newly diagnosed MM met the eligibility criteria for this study. The choice of the algorithm did not impact the characteristics of identified patients with TCR MM (Algorithm 1 [n = 404], Algorithm 2 [n = 123], Algorithm 3 [n = 404], and Algorithm 4 [n = 375]), including their demographic and disease characteristics, MM treatment history, or treatment patterns received after becoming TCR. However, identifying TCR MM using a combination of IMWG-derived and HCP-reported progressions allowed up to a 70% increase in the size of the identified group of patients compared with using only IMWG-derived progressions. Conclusion: In RW settings, progressions from both IMWG-derived data and physician reports may be used to identify patients with TCR MM.

Mitochondrial pyruvate carrier 1: a novel prognostic biomarker that predicts favourable patient survival in cancer

Mitochondrial pyruvate carrier 1 (MPC1) is a key metabolic protein that regulates the transport of pyruvate into the mitochondrial inner membrane. MPC1 deficiency may cause metabolic reprogramming. However, whether and how MPC1 controls mitochondrial oxidative capacity in cancer are still relatively unknown. MPC1 deficiency was recently found to be strongly associated with various diseases and cancer hallmarks. We utilized online databases and uncovered that MPC1 expression is lower in many cancer tissues than in adjacent normal tissues. In addition, MPC1 expression was found to be substantially altered in five cancer types: breast-invasive carcinoma (BRCA), kidney renal clear cell carcinoma (KIRC), lung adenocarcinoma (LUAD), pancreatic adenocarcinoma (PAAD), and prostate adenocarcinoma (PRAD). However, in KIRC, LUAD, PAAD, and PRAD, high MPC1 expression is closely associated with favourable prognosis. Low MPC1 expression in BRCA is significantly associated with shorter overall survival time. MPC1 expression shows strong positive and negative correlations with immune cell infiltration in thymoma (THYM) and thyroid carcinoma (THCA). Furthermore, we have comprehensively summarized the current literature regarding the metabolic reprogramming effects of MPC1 in various cancers. As shown in the literature, MPC1 expression is significantly decreased in cancer tissue and associated with poor prognosis. We discuss the potential metabolism-altering effects of MPC1 in cancer, including decreased pyruvate transport ability; impaired pyruvate-driven oxidative phosphorylation (OXPHOS); and increased lactate production, glucose consumption, and glycolytic capacity, and the underlying mechanisms. These activities facilitate tumour progression, migration, and invasion. MPC1 is a novel cancer biomarker and potentially powerful therapeutic target for cancer diagnosis and treatment. Further studies aimed at slowing cancer progression are in progress.

The clinical significance of CD49e and CD56 for multiple myeloma in the novel agents era

Multiple myeloma (MM) is a hematological malignancy characterized by the proliferation of abnormal plasma cells in bone marrow. Flow cytometry distinguishes between normal and abnormal plasma cells by evaluating cluster of differentiation (CD) 56 and CD19 expression patterns. Moreover, immunophenotyping of mature plasma cell 1 (MPC-1) and very late antigen-5 (CD49e) identifies the maturity of MM as mature (MPC-1⁺, CD49e⁺), intermediate (MPC-1⁺, CD49e^-), or immature (MPC-1^-, CD49e^-). We retrospectively examined the effects of surface marker expression and maturity subtype on overall survival (OS) and time to next treatment (TNT) among 55 patients (25 males, 30 females) with symptomatic MM. All patients were treated with regimens containing bortezomib (BOR) (n = 39) or lenalidomide (LEN) (n = 16) as the initial treatment. Median age at diagnosis was 72 years (range: 36-88). The lack of CD56, an aberrant marker, was associated with significantly worse prognosis compared with CD56⁺ MM (median OS: 24 vs. 60 months, respectively; p = 0.0050). In CD49e⁺ MM, defined as mature type, no significant difference was seen in TNT of the initial treatment, regardless of whether it was a BOR-based regimen or LEN + dexamethasone (Ld) therapy. On the other hand, in CD49e^- MM, defined as immature/intermediate type, TNT of Ld therapy was significantly longer than that of BOR-based regimens (median TNT: undefined vs. 12 months, respectively; p = 0.0043). These results suggest that Ld therapy is more effective than BOR-based therapy for CD49e^- MM and thus may aid regimen-related decisions in the novel agents era.

Targeted Therapy With Immunoconjugates for Multiple Myeloma

The introduction of proteasome inhibitors (PI) and immunomodulatory drugs (IMiD) has markedly increased the survival of multiple myeloma (MM) patients. Also, the unconjugated monoclonal antibodies (mAb) daratumumab (anti-CD38) and elotuzumab (anti-SLAMF7) have revolutionized MM treatment given their clinical efficacy and safety, illustrating the potential of targeted immunotherapy as a powerful treatment strategy for MM. Nonetheless, most patients eventually develop PI-, IMiD-, and mAb-refractory disease because of the selection of resistant MM clones, which associates with a poor prognosis. Accordingly, these patients remain in urgent need of new therapies with novel mechanisms of action. In this respect, mAbs or mAb fragments can also be utilized as carriers of potent effector moieties to specifically target surface antigens on cells of interest. Such immunoconjugates have the potential to exert anti-MM activity in heavily pretreated patients due to their distinct and pleiotropic mechanisms of action. In addition, the fusion of highly cytotoxic compounds to mAbs decreases the off-target toxicity, thereby improving the therapeutic window. According to the effector moiety, immunoconjugates are classified into antibody-drug conjugates, immunotoxins, immunocytokines, or radioimmunoconjugates. This review will focus on the mechanisms of action, safety and efficacy of several promising immunoconjugates that are under investigation in preclinical and/or clinical MM studies. We will also include a discussion on combination therapy with immunoconjugates, resistance mechanisms, and future developments.