Faculty Bibliography

Most patients with newly diagnosed multiple myeloma (MM) are aged > 65 years with 30% aged > 75 years. Many elderly patients are also vulnerable because of comorbidities that complicate the management of MM. The prevalence of MM is expected to rise over time because of an aging population. Most elderly patients with MM are ineligible for autologous transplantation, and the standard treatment has, until recently, been melphalan plus prednisone. The introduction of novel agents, such as thalidomide, bortezomib, and lenalidomide, has improved outcomes; however, elderly patients with MM are more susceptible to side effects and are often unable to tolerate full drug doses. For these patients, lower-dose-intensity regimens improve the safety profile and thus optimize treatment outcome. Further research into the best treatment strategies for vulnerable elderly patients is urgently needed. Appropriate screening for vulnerability and an assessment of cardiac, pulmonary, renal, hepatic, and neurologic functions, as well as age > 75 years, at the start of therapy allows treatment strategies to be individualized and drug doses to be tailored to improve tolerability and optimize efficacy. Similarly, occurrence of serious nonhematologic adverse events during treatment should be carefully taken into account to adjust doses and optimize outcomes.

An expert panel convened to reach a consensus regarding the optimal use of lenalidomide in combination with dexamethasone (Len/Dex) in patients with relapsed or refractory multiple myeloma (RRMM). On the basis of the available evidence, the panel agreed that Len/Dex is a valid and effective treatment option for most patients with RRMM. As with other therapies, using Len/Dex at first relapse is more effective regarding response rate and durability than using it after multiple salvage therapies. Len/Dex may be beneficial regardless of patient age, disease stage and renal function, although the starting dose of lenalidomide should be adjusted for renal impairment and cytopenias. Long-term treatment until there is evidence of disease progression may be recommended at the best-tolerated doses of both lenalidomide and dexamethasone. Recommendations regarding the prevention and management of adverse events, particularly venous thromboembolism and myelosuppression, were provided on the basis of the available evidence and practical experience of panel members. Ongoing trials will provide more insight into the effects of continuous lenalidomide-based therapy in myeloma.

We used genome-wide methylation microarrays to analyze differences in CpG methylation patterns in cells relevant to the pathogenesis of myeloma plasma cells (B cells, normal plasma cells, monoclonal gammopathy of undetermined significance [MGUS], presentation myeloma, and plasma cell leukemia). We show that methylation patterns in these cell types are capable of distinguishing nonmalignant from malignant cells and the main reason for this difference is hypomethylation of the genome at the transition from MGUS to presentation myeloma. In addition, gene-specific hypermethylation was evident at the myeloma stage. Differential methylation was also evident at the transition from myeloma to plasma cell leukemia with remethylation of the genome, particularly of genes involved in cell-cell signaling and cell adhesion, which may contribute to independence from the bone marrow microenvironment. There was a high degree of methylation variability within presentation myeloma samples, which was associated with cytogenetic differences between samples. More specifically, we found methylation subgroups were defined by translocations and hyperdiploidy, with t(4;14) myeloma having the greatest impact on DNA methylation. Two groups of hyperdiploid samples were identified, on the basis of unsupervised clustering, which had an impact on overall survival. Overall, DNA methylation changes significantly during disease progression and between cytogenetic subgroups.

PURPOSE/OBJECTIVE:To indentify genetic variation that can modulate and predict the risk of developing thalidomide-related peripheral neuropathy (TrPN). PATIENTS AND METHODS/METHODS:We analyzed DNA from 1,495 patients with multiple myeloma. Using a custom-built single nucleotide polymorphism (SNP) array, we tested the association of TrPN with 3,404 SNPs. The SNPs were selected in predicted functional regions within 964 genes spanning 67 molecular pathways thought to be involved in the pathogenesis, treatment response, and adverse effects associated with myeloma and its therapy. Patient cases and controls were derived from two large clinical trials that compared thalidomide with conventional-based treatment in myeloma patients (Medical Research Council Myeloma-IX and HOVON-50/GMMG-HD3). RESULTS:We report TrPN associations with SNPs-ABCA1 (rs363717), ICAM1 (rs1799969), PPARD (rs2076169), SERPINB2 (rs6103), and SLC12A6 (rs7164902)-where we show cross validation of the associations in both trials. To investigate whether TrPN SNP associations were related to exposure to thalidomide only or general drug-related peripheral neuropathy, we performed a second analysis on patients treated with vincristine. We report SNPs associated with vincristine neuropathy, with a seemingly distinct underlying genetic mechanism. CONCLUSION/CONCLUSIONS:Our results are consistent with the hypothesis that an individual's risk of developing a peripheral neuropathy after thalidomide treatment can be mediated by polymorphisms in genes governing repair mechanisms and inflammation in the peripheral nervous system. These findings will contribute to the development of future neuroprotective strategies with thalidomide therapy and the better use of this important compound.

Ire1 (Ern1) is an unusual transmembrane protein kinase essential for the endoplasmic reticulum (ER) unfolded protein response (UPR). Activation of Ire1 by association of its N-terminal ER luminal domains promotes autophosphorylation by its cytoplasmic kinase domain, leading to activation of the C-terminal ribonuclease domain, which splices Xbp1 mRNA generating an active Xbp1s transcriptional activator. We have determined the crystal structure of the cytoplasmic portion of dephosphorylated human Ire1α bound to ADP, revealing the 'phosphoryl-transfer' competent dimeric face-to-face complex, which precedes and is distinct from the back-to-back RNase 'active' conformation described for yeast Ire1. We show that the Xbp1-specific ribonuclease activity depends on autophosphorylation, and that ATP-competitive inhibitors staurosporin and sunitinib, which inhibit autophosphorylation in vitro, also inhibit Xbp1 splicing in vivo. Furthermore, we demonstrate that activated Ire1α is a competent protein kinase, able to phosphorylate a heterologous peptide substrate. These studies identify human Ire1α as a target for development of ATP-competitive inhibitors that will modulate the UPR in human cells, which has particular relevance for myeloma and other secretory malignancies.