Survival analysis of multiple myeloma patients after autologous stem cell transplantation

GPC-100, a novel CXCR4 antagonist, improves in vivo hematopoietic cell mobilization when combined with propranolol

Autologous Stem Cell Transplant (ASCT) is increasingly used to treat hematological malignancies. A key requisite for ASCT is mobilization of hematopoietic stem cells into peripheral blood, where they are collected by apheresis and stored for later transplantation. However, success is often hindered by poor mobilization due to factors including prior treatments. The combination of G-CSF and GPC-100, a small molecule antagonist of CXCR4, showed potential in a multiple myeloma clinical trial for sufficient and rapid collection of CD34+ stem cells, compared to the historical results from the standards of care, G-CSF alone or G-CSF with plerixafor, also a CXCR4 antagonist. In the present study, we show that GPC-100 has high affinity towards the chemokine receptor CXCR4, and it potently inhibits β-arrestin recruitment, calcium flux and cell migration mediated by its ligand CXCL12. Proximity Ligation Assay revealed that in native cell systems with endogenous receptor expression, CXCR4 co-localizes with the beta-2 adrenergic receptor (β2AR). Co-treatment with CXCL12 and the β2AR agonist epinephrine synergistically increases β-arrestin recruitment to CXCR4 and calcium flux. This increase is blocked by the co-treatment with GPC-100 and propranolol, a non-selective beta-adrenergic blocker, indicating a functional synergy. In mice, GPC-100 mobilized more white blood cells into peripheral blood compared to plerixafor. GPC-100 induced mobilization was further amplified by propranolol pretreatment and was comparable to mobilization by G-CSF. Addition of propranolol to the G-CSF and GPC-100 combination resulted in greater stem cell mobilization than the G-CSF and plerixafor combination. Together, our studies suggest that the combination of GPC-100 and propranolol is a novel strategy for stem cell mobilization and support the current clinical trial in multiple myeloma registered as NCT05561751 at www.clinicaltrials.gov.

Role of Anti-B-Cell Maturation Antigen (BCMA) in the Management of Multiple Myeloma

Simple Summary

Multiple myeloma is the most prevalent hematological cancer, and further treatments for this disease are required. Despite progress in the development of treatment regimens, multiple myeloma is still an incurable disease because of its poor response to therapy and high rate of resistance to treatment. However, anti-BCMA (B-cell maturation antigen) has shown promise in the treatment of multiple myeloma, and it may have the potential to be a new first-line treatment for patients. Thus, in this review, we objectively discussed the treatment potential of anti-BCMA, its mechanisms, and its future clinical implications for multiple myeloma patients.

Abstract

Over the past few decades, treatment options have become more advanced for multiple myeloma (MM), one of the most prevalent hematological cancers; however, multiple myeloma remains an incurable disease due to its poor response to therapy and high rates of resistance, which cause relapsed/refractory or multiple myeloma. Researchers have described anti-BCMA (B-cell maturation antigen) as a promising treatment regimen that targets the BCMA biomarker in the affected plasma cells. BCMA is a protein that is specifically expressed in plasma-cell neoplasms by using several mechanisms, such as CAR T cells (Chimeric Antigen Receptor T cells), antibody-drug conjugates, and bispecific T-cell engagers, thus allowing for a rapid response in the treatment of resistant or relapsed/refractory multiple myeloma patients. Anti-BCMA treatment is novel and specific in its mechanisms of action, with noninferior complete responses, higher overall survival rates, and fewer reported adverse events compared to other currently available treatment of MM. In this review, we compared anti-BCMA mechanisms with those of previously available therapies, such as those using immunomodulators and proteasome inhibitors, and discussed the advantages of using anti-BCMA as a potential first-line treatment for multiple myeloma patients.