Ness, Brian G. Van

Abstract We have taken a genetic strategy to define the mechanisms underlying the increased risk of VTE in myeloma patient treated with thalidomide using clinical trial data derived from the MRC, ECOG, Little Rock and HOVON trial groups. Baseline VTE rates in the MRC IX study, (CTD vs CVAD; n=748 no prophylactic anticoagulation), were 14%. Rates in both arms were equal but in the thalidomide arm, thrombotic events were all DVT’s or PE’s, whereas in the CVAD arm they split equally between line related and VTE’s. In the other comparison (CTD vs MP; n=542), the VTE rate was 17%, all in the thalidomide arm. Rates were similar or higher (30%) in the other trials depending on the intensity of treatment used. We carried out a nested case control on DNA from MRC IX on 90 VTE (45 thalidomide, 45 non-thalidomide related), matched to 180 controls. SNPlex analysis for 60 SNPs in the coagulation cascade, DNA repair, thalidomide, metabolism and myeloma specific pathways, identified 7 genes which affected risk (NBS1, MTHFR, Ku80, Cyp3A5, LGAL52 and IL12B). This suggests three major pathways contribute to the risk of thalidomide related VTE, metabolism of thalidomide, tumour responsiveness and some pro-thrombotic factors. These factors differ from non-thalidomide related risk where a strong pro-inflammatory response is most relevant. We tested this hypothesis further using an expanded panel of 3,404 SNPs (BOAC panel), using the Megalle system. Statistical analysis of this data defined the top 20 thalidomide and non-thalidomide associated SNPs, which were consistent with the initial hypothesis, the results of which exclude variation in the coagulation cascade as being a significant risk factor. We explored this hypothesis further using pathway-based analysis focussing on the MTHFR, DNA repair and WNT pathways on data from the ECOG, HOVON and Little Rock data sets. The biological relevance of the SNPs and genes identified was validated by correlating the level of expression using the Affymetrix U133 CHIP with genetic variation at the DNA level. To verify the relevance of DNA repair variability to tumour response further, we correlated gene expression profiling with response and again Ku80 was identified as one of a cluster of genes defining increased risk. The data suggests that the risk of thalidomide related VTE relates to rapid tumour lysis combined with a prothrombotic tendency, whereas in line related thrombosis, risk is dependent upon a strong proinflammatory response. We are building this genetic data into a clinical risk model in order to allow us to develop a rationale for intervention strategies.

AbstractPreviously, it was reported that patients with multiple myeloma (MM) who have higher baseline levels of blood CD4+or CD19+ cells have longer survival. This article extends the analysis of immune cell levels and survival in a large cohort (N = 504) of patients with MM entered on Eastern Cooperative Oncology Group (ECOG) phase 3 trial (9486). Newly diagnosed patients with MM received 2 cycles of vincristine, bischloroethylnitrosourea, melphalan, cytoxan, prednisone (VBMCP) and were treated on one of 3 randomized arms: VBMCP with either interferon or high-dose cyclophosphamide, or VBMCP alone. Blood immune cell levels were studied at trial entry (baseline), after 2 cycles of chemotherapy, after 2 years of therapy, and at relapse. Baseline CD3+, CD4+, CD8+, CD19+, and CD4+ subset cell levels were all positively associated with survival (P = .0087 toP < .0001). A multivariate analysis incorporating CD4+ and CD19+ cell levels defined 3 separate groups of patients with MM to survival outcome. Higher CD19+ blood levels were positively associated with MM-patient survival at entry to the study, at year 2, and at relapse (P < .0001 at all 3 timepoints). Patients with MM had evidence of immune cell reconstitution after 2 years of therapy, but the rate and extent of recovery was greater for CD8+, which was greater than CD4+, which was greater than CD19+. This latter data affirms the positive relationship between the quantitative status of the blood immune system in MM and survival. In addition, the importance of the CD19+ blood cells to survival is evident throughout the course of MM. Therapeutic efforts to maintain an intact immune system may be crucial in maximizing chemotherapeutic and/or immunotherapy efforts in this disease.