Disease heterogeneity, prognostication and the role of targeted therapy in multiple myeloma

Epidemiology, Treatment Trends, and Outcomes of Multiple Myeloma in the Middle East and Africa: A Systematic Review

Background

Globally, multiple myeloma (MM) ranks 24th among the most common cancers. The Middle East and Africa are affected by an increasing trend in MM incidence, owing to several underlying factors. This systematic review aims to assess the epidemiology, patient characteristics, and treatment outcomes associated with MM in selected countries in the Middle East and Africa.

Methods

An electronic search was performed in the PubMed/MEDLINE database. Abstracts presented at the annual meetings of the American Society of Clinical Oncology, American Society of Hematology, and European Society for Medical Oncology and the GLOBOCAN registry were searched. Qualitative analysis was performed.

Results

A total of 412 articles were screened, and 14 were selected. The five-year prevalence per 100,000 gathered from country-wise GLOBOCAN data ranged between 155 in Kuwait and 5,625 in North Africa. The identified treatment options were proteasome inhibitors such as bortezomib, drugs such as thalidomide, lenalidomide, dexamethasone, melphalan, and cyclophosphamide, and newer drugs such as daratumumab.

Conclusion

Improved diagnostic capability has increased the incidence of MM in this region. However, advanced drugs and treatment regimens remain unaffordable in many countries of these regions. Therefore, understanding the trends of the disease and improving healthcare settings are imperative.

IGH::NSD2 Fusion Gene Transcript as Measurable Residual Disease Marker in Multiple Myeloma

Multiple myeloma (MM) is the second most common hematological malignancy. Approximately 15% of MM patients are affected by the t(4;14) translocation resulting in the IGH::NSD2 fusion transcript. Breakage occurs in three major breakpoint regions within the NSD2 gene (MB4-1, MB4-2, and MB4-3), where MB4-1 leads to the production of full-length protein, while truncated proteins are expressed in the other two cases. Measurable residual disease (MRD) has been conclusively established as a crucial prognostic factor in MM. The IGH::NSD2 fusion transcript can serve as a sensitive MRD marker. Using bone marrow (BM) and peripheral blood (PB) samples from 111 patients, we developed a highly sensitive quantitative real-time PCR (qPCR) and digital PCR (dPCR) system capable of detecting fusion mRNAs with a sensitivity of up to 1:100,000. PB samples exhibited sensitivity three orders of magnitude lower compared to BM samples. Patients with an MB4-2 breakpoint demonstrated significantly reduced overall survival (p = 0.003). Our novel method offers a simple and sensitive means for detecting MRD in a substantial proportion of MM patients. Monitoring may be carried out even from PB samples. The literature lacks consensus regarding survival outcomes among patients with different NSD2 breakpoints. Our data align with previous findings indicating that patients with the MB4-2 breakpoint type tend to exhibit unfavorable overall survival.

CTPS1 is a novel therapeutic target in multiple myeloma which synergizes with inhibition of CHEK1, ATR or WEE1

Targeting nucleotide biosynthesis is a proven strategy for the treatment of cancer but is limited by toxicity, reflecting the fundamental nucleotide requirement of dividing cells. The rate limiting step in de novo pyrimidine synthesis is of interest, being catalyzed by two homologous enzymes, CTP synthase 1 (CTPS1) and CTPS2, that could be differentially targeted. Herein, analyses of publicly available datasets identified an essential role for CTPS1 in multiple myeloma (MM), linking high expression of CTPS1 (but not CTPS2) with advanced disease and poor outcomes. In cellular experiments, CTPS1 knockout induced apoptosis of MM cell lines. Exposure of MM cells to STP-B, a novel and highly selective pharmacological inhibitor of CTPS1, inhibited proliferation, induced S phase arrest and led to cell death by apoptosis. Mechanistically, CTPS1 inhibition by STP-B activated DNA damage response (DDR) pathways and induced double-strand DNA breaks which accumulated in early S phase. Combination of STP-B with pharmacological inhibitors of key components of the DDR pathway (ATR, CHEK1 or WEE1) resulted in synergistic growth inhibition and early apoptosis. Taken together, these findings identify CTPS1 as a promising new target in MM, either alone or in combination with DDR pathway inhibition.

Low Barthel index score is a poor prognostic factor for newly diagnosed multiple myeloma patients

The basic activities of daily life may affect the prognosis of multiple myeloma (MM) patients and the Barthel index (BI) is currently the most widely used tool to evaluate basic activities of daily life, but few studies have evaluated its prognostic value in MM. We retrospectively enrolled patients with newly diagnosed MM and analyzed the association between the BI and the survival of newly diagnosed MM patients. We totally analyzed 538 patients and found that median overall survival (OS) and progression-free survival (PFS) were significantly shorter in the low BI (≤ 85) group compared with the high BI (> 85) group. Univariate Cox proportional hazards regression analysis showed that the low BI was associated with shorter OS and PFS. It was also confirmed that the low BI was poor prognostic factor for OS and PFS in multivariable analyses. In the propensity score matching analysis, patients with low BI also had shorter OS and PFS. Our study suggested that the low BI was a poor prognostic factor for patients with newly diagnosed MM.