Bergsagel, P. Leif

Key Points IMiDs inhibit TrxR-mediated intracellular decomposition of H2O2 and caused oxidative stress in MM cells. MM cells with lower antioxidative capacity were more vulnerable to lenalidomide-induced H2O2 accumulation and its associated cytotoxicity.

Key Points The combination of ixazomib and dexamethasone has clinical activity in patients with relapsed and or refractory multiple myeloma. Higher dose of ixazomib leads to improved response rates but with higher rates of treatment related adverse events.

Key Points The incidence of mutations within the MAPK pathway, the CRBN pathway, and TP53 is significantly increased in drug-refractory MM. Mutations in CRBN might contribute to IMiD resistance in drug-refractory MM.

Purpose The aim of the International Myeloma Working Group was to develop practical recommendations for the diagnosis and management of multiple myeloma–related renal impairment (RI). Methods Recommendations were based on published data through December 2015, and were developed using the system developed by the Grading of Recommendation, Assessment, Development, and Evaluation Working Group. Recommendations All patients with myeloma at diagnosis and at disease assessment should have serum creatinine, estimated glomerular filtration rate, and electrolytes measurements as well as free light chain, if available, and urine electrophoresis of a sample from a 24-hour urine collection (grade A). The Chronic Kidney Disease Epidemiology Collaboration, preferably, or the Modification of Diet in Renal Disease formula should be used for the evaluation of estimated glomerular filtration rate in patients with stabilized serum creatinine (grade A). International Myeloma Working Group criteria for renal reversibility should be used (grade B). For the management of RI in patients with multiple myeloma, high fluid intake is indicated along with antimyeloma therapy (grade B). The use of high-cutoff hemodialysis membranes in combination with antimyeloma therapy can be considered (grade B). Bortezomib-based regimens remain the cornerstone of the management of myeloma-related RI (grade A). High-dose dexamethasone should be administered at least for the first month of therapy (grade B). Thalidomide is effective in patients with myeloma with RI, and no dose modifications are needed (grade B). Lenalidomide is effective and safe, mainly in patients with mild to moderate RI (grade B); for patients with severe RI or on dialysis, lenalidomide should be given with close monitoring for hematologic toxicity (grade B) with dose reduction as needed. High-dose therapy with autologous stem cell transplantation (with melphalan 100 mg/m 2 to 140 mg/m 2 ) is feasible in patients with RI (grade C). Carfilzomib can be safely administered to patients with creatinine clearance > 15 mL/min, whereas ixazomib in combination with lenalidomide and dexamethasone can be safely administered to patients with creatinine clearance > 30 mL/min (grade A).

Abstract Angiogenesis has been postulated to be critical for the pathogenesis of multiple myeloma, a neoplastic disease characterized by abnormal proliferation of malignant plasma cells in the bone marrow (BM). Cleavage of the N- and C-terminal regions of circulating chromogranin A (CgA, CHGA), classically an antiangiogenic protein, can activate latent antiangiogenic and proangiogenic sites, respectively. In this study, we investigated the distribution of CgA-derived polypeptides in multiple myeloma patients and the subsequent implications for disease progression. We show that the ratio of pro/antiangiogenic forms of CgA is altered in multiple myeloma patients compared with healthy subjects and that this ratio is higher in BM plasma compared with peripheral plasma, suggesting enhanced local cleavage of the CgA C-terminal region. Enhanced cleavage correlated with increased VEGF and FGF2 BM plasma levels and BM microvascular density. Using the Vk*MYC mouse model of multiple myeloma, we further demonstrate that exogenously administered CgA was cleaved in favor of the proangiogenic form and was associated with increased microvessel density. Mechanistic studies revealed that multiple myeloma and proliferating endothelial cells can promote CgA C-terminal cleavage by activating the plasminogen activator/plasmin system. Moreover, cleaved and full-length forms could also counter balance the pro/antiangiogenic activity of each other in in vitro angiogenesis assays. These findings suggest that the CgA-angiogenic switch is activated in the BM of multiple myeloma patients and prompt further investigation of this CgA imbalance as a prognostic or therapeutic target. Cancer Res; 76(7); 1781–91. ©2016 AACR.