CAR-T-Cell Therapy in Multiple Myeloma: B-Cell Maturation Antigen (BCMA) and Beyond

Significant progress has been achieved in the realm of therapeutic interventions for multiple myeloma (MM), leading to transformative shifts in its clinical management. While conventional modalities such as surgery, radiotherapy, and chemotherapy have improved the clinical outcomes, the overarching challenge of effecting a comprehensive cure for patients afflicted with relapsed and refractory MM (RRMM) endures. Notably, adoptive cellular therapy, especially chimeric antigen receptor T-cell (CAR-T) therapy, has exhibited efficacy in patients with refractory or resistant B-cell malignancies and is now also being tested in patients with MM. Within this context, the B-cell maturation antigen (BCMA) has emerged as a promising candidate for CAR-T-cell antigen targeting in MM. Alternative targets include SLAMF7, CD38, CD19, the signaling lymphocyte activation molecule CS1, NKG2D, and CD138. Numerous clinical studies have demonstrated the clinical efficacy of these CAR-T-cell therapies, although longitudinal follow-up reveals some degree of antigenic escape. The widespread implementation of CAR-T-cell therapy is encumbered by several barriers, including antigenic evasion, uneven intratumoral infiltration in solid cancers, cytokine release syndrome, neurotoxicity, logistical implementation, and financial burden. This article provides an overview of CAR-T-cell therapy in MM and the utilization of BCMA as the target antigen, as well as an overview of other potential target moieties.

Bevacizumab beyond progression: Impact of subsequent bevacizumab retreatment in patients with ovarian, fallopian tube, and peritoneal cancer after progression

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Background: The Food and Drug Administration approved the use of bevacizumab for treatment of recurrent epithelial ovarian, fallopian tube, and primary peritoneal carcinoma (OC) in combination with chemotherapy. This study evaluates whether patients immediately retreated with bevacizumab derive benefit after progressing on a bevacizumab-containing regimen. Methods: This multi-institutional, retrospective study compared patients with high grade non-mucinous epithelial OC who received bevacizumab followed directly by another bevacizumab-containing treatment regimen to patients who received bevacizumab followed by a regimen that did not contain bevacizumab (or received no further treatment). All patient retreated with bevacizumab had stable or progressive disease on prior bevacizumab containing regimen. Progression free survival (PFS) and overall survival (OS) were estimated using Kaplan and Meier product-limit estimator and modeled via Cox proportional hazards regression. PFS was measured from the date of first bevacizumab treatment to the date of first progression, date of death or date of last clinic visit. OS was measured from the date of first bevacizumab treatment after progression to the date of death or date of last contact/clinic visit. Statistical significance was defined at the 0.05 level. Results: 275 patients received bevacizumab, of which 226 were evaluable; 102 received sequential treatment with bevacizumab and 124 received a bevacizumab containing regimen followed by a non-bevacizumab containing regimen at the time of progression. There was no significant difference between tumor grade, stage, or BRCA mutation. Median follow-up for all subjects was 17 months (range: 1.2-138.2 months). Median PFS was 10.21 months (95%CI: 8.05 - 11.79) and median OS was 22.14 months (95%CI: 17.1 – 27.4). Median PFS for patients who received bevacizumab without retreatment was 5.1 months (95%CI: 4.3 – 6.3) and 17.6 months (95%CI: 14.3 – 21.3) for patients who received sequential bevacizumab retreatment (p < 0.001). Median OS for patients who received bevacizumab without retreatment was 12.9 months (95%CI: 9.3 – 16.7) and 30.1 months (95%CI: 26.1 – 35.4) for patients who received sequential bevacizumab retreatment (p < 0.001). Conclusions: Our study shows OC patients treated with bevacizumab-containing regimens sequentially at the time of progression have significantly prolonged survival outcomes compared to those patients who received no re-treatment with bevacizumab.

Ovarian Cancer: Clinical Trial Breakthroughs and Impact on Management

Ovarian cancer treatment continues to evolve. Despite aggressive surgery and chemotherapy, most women will ultimately die from disease. Improvement in disease control are due to the incorporation of molecular targeted agents and the adoption of maintenance therapy. Maintenance therapy has been shown to enhance progression-free survival. Recent surgical trials have evaluated the role of neoadjuvant chemotherapy versus primary debulking at the time of diagnosis in advanced stage ovarian cancer. The role of lymph node dissection and secondary cytoreductive surgeries have also been evaluated. This article reviews contemporary trials of maintenance therapy and novel drug development.

Hypoxia-upregulated microRNA-630 targets Dicer, leading to increased tumor progression

MicroRNAs (miRNAs) are small RNA molecules that affect cellular processes by controlling gene expression. Recent studies have shown that hypoxia downregulates Drosha and Dicer, key enzymes in miRNA biogenesis, causing a decreased pool of miRNAs in cancer and resulting in increased tumor growth and metastasis. Here we demonstrate a previously unrecognized mechanism by which hypoxia downregulates Dicer. We found that miR-630, which is upregulated under hypoxic conditions, targets and downregulates Dicer expression. In an orthotopic mouse model of ovarian cancer, delivery of miR-630 using 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) nanoliposomes resulted in increased tumor growth and metastasis, and decreased Dicer expression. Treatment with the combination of anti-miR-630 and anti-vascular endothelial growth factor antibody in mice resulted in rescue of Dicer expression and significantly decreased tumor growth and metastasis. These results indicate that targeting miR-630 is a promising approach to overcome Dicer deregulation in cancer. As demonstrated in the study, use of DOPC nanoliposomes for anti-miR delivery serves as a better alternative approach to cell line-based overexpression of sense or antisense miRNAs, while avoiding potential in vitro selection effects. Findings from this study provide a new understanding of miRNA biogenesis downregulation observed under hypoxia and suggest therapeutic avenues to target this dysregulation in cancer.

A prognostic nomogram to predict overall survival in women with recurrent ovarian cancer treated with bevacizumab and chemotherapy

OBJECTIVE

To develop a nomogram to predict overall survival (OS) in women with recurrent ovarian cancer treated with bevacizumab and chemotherapy.

METHODS

A multicenter retrospective study was conducted. Potential prognostic variables included age; stage; grade; histology; performance status; residual disease; presence of ascites and/or pleural effusions; number of chemotherapy regimens, treatment-free interval (TFI) prior to bevacizumab administration, and platinum sensitivity. Multivariate analysis was performed using Cox proportional hazards regression. The predictive model was developed into a nomogram to predict five-year OS.

RESULTS

312 women with recurrent ovarian cancer treated with bevacizumab and chemotherapy were identified; median age was 59 (range: 19-85); 86% women had advanced stage (III-IV) disease. The majority had serous histology (74%), high grade cancers (93.5%), and optimal cytoreductions (69.5%). Fifty-one percent of women received greater than two prior chemotherapeutic regimens. TFI (AHR=0.98, 95% CI 0.97-1.00, p=0.022) was the only statistically significant predictor in a multivariate progression-free survival (PFS) analysis. In a multivariate OS analysis, prior number of chemotherapy regimens, TFI, platinum sensitivity, and presence of ascites were significant. A nomogram to predict five-year OS was constructed and internally validated (bootstrap-corrected concordance index=0.737).

CONCLUSION

Our multivariate model identified prior number of chemotherapy regimens, TFI, platinum sensitivity, and the presence of ascites as prognostic variables for OS in women with recurrent ovarian cancer treated with bevacizumab combined with chemotherapy. Our nomogram to predict five-year OS may be used to identify women who may benefit from bevacizumab and chemotherapy, but further validation is needed.