Faculty Bibliography

BACKGROUND AND OBJECTIVE/OBJECTIVE:Methylating agents are effective chemotherapy agents for Hodgkin lymphoma, but are associated with the development of second primary cancers. Cytotoxicity of methylating agents is mediated primarily by the DNA mismatch repair (MMR) system. Loss of MLH1, a major component of DNA MMR, results in tolerance to the cytotoxic effects of methylating agents and persistence of mutagenised cells at high risk of malignant transformation. We hypothesised that a common substitution in the basal promoter of MLH1 (position -93, rs1800734) modifies the risk of cancer after methylating chemotherapy. METHODS:133 patients who developed cancer following chemotherapy and/or radiotherapy (n = 133), 420 patients diagnosed with de novo myeloid leukaemia, 242 patients diagnosed with primary Hodgkin lymphoma, and 1177 healthy controls were genotyped for the MLH1 -93 polymorphism by allelic discrimination polymerase chain reaction (PCR) and restriction fragment length polymorphism assay. Odds ratios and 95% confidence intervals for cancer risk by MLH1 -93 polymorphism status, and stratified by previous exposure to methylating chemotherapy, were calculated using unconditional logistic regression. RESULTS:Carrier frequency of the MLH1 -93 variant was higher in patients who developed therapy related acute myeloid leukaemia (t-AML) (75.0%, n = 12) or breast cancer (53.3%. n = 15) after methylating chemotherapy for Hodgkin lymphoma compared to patients without previous methylating exposure (t-AML, 30.4%, n = 69; breast cancer patients, 27.2%, n = 22). The MLH1 -93 variant allele was also over-represented in t-AML cases when compared to de novo AML cases (36.9%, n = 420) and healthy controls (36.3%, n = 952), and was associated with a significantly increased risk of developing t-AML (odds ratio 5.31, 95% confidence interval 1.40 to 20.15), but only in patients previously treated with a methylating agent. CONCLUSIONS:These data support the hypothesis that the common polymorphism at position -93 in the core promoter of MLH1 defines a risk allele for the development of cancer after methylating chemotherapy for Hodgkin lymphoma. However, replication of this finding in larger studies is suggested.

A total of 100 adults with ALL in first CR received melphalan (110 mg/m(2)) with TBI followed by autologous marrow (n=35) or single-agent melphalan (200 mg/m(2)) followed by autologous blood stem cells (n=65). After adequate hematologic recovery, maintenance chemotherapy with 6-mercaptopurine, methotrexate and vincristine-prednisone was administered for 2 years. Six patients, all TBI recipients (P=0.001), died of toxicity. In total 70 patients received 6-mercaptopurine, 53 received methotrexate and 40 received vincristine-prednisone. The cumulative incidence of relapse at 7 years was 45%. The 7-year probabilities of disease-free survival (DFS) and overall survival were 45 and 48%. Age 30 years, >4 weeks to attain remission, and karyotypes t(4;11) and t(9;22) were associated with adverse outcome. Patients with 0 (standard risk), 1 (intermediate risk), and 2-3 (high risk) adverse features had 7-year cumulative incidences of relapse of 19, 53 and 82% (P<0.0001), and 7-year DFS probabilities of 73, 36 and 7% (P<0.0001). The 7-year probabilities of DFS for patients receiving 0, 1, 2 and 3 maintenance chemotherapy agents were 15, 29, 58 and 61% (P<0.0001). Maintenance chemotherapy intensity was an independent determinant of outcome in Cox analysis. Maintenance chemotherapy after autotransplantation reduces relapse and improves outcome in adult patients with ALL.

One-hundred-twenty consecutive adult patients aged 15-69 years (median 40) with acute myeloid leukemia (AML) excluding t(15;17) received induction therapy comprising idarubicin, high-dose cytarabine and etoposide. Planned post-induction treatment included two courses of moderate-intensity consolidation therapy followed by stem cell transplantation. 11 patients (9%) died during induction therapy. The complete remission (CR) rate with a single cycle of induction therapy was 71%. The overall CR rate, after salvage chemotherapy but excluding allogeneic transplantation for primary refractory disease, was 82%. CR rates with one cycle of therapy for patients with good, intermediate and poor karyotype were 96, 72 and 41%, respectively (P<0.0001). The impact of karyotype on the overall CR rate was also significant (96 vs. 88 vs. 59%; P=0.001). Overall, 84 of 98 patients (86%) attaining CR underwent autologous (n=59), allogeneic (n=23) or syngeneic (n=2) hematopoietic stem cell transplantation in first CR. The 5-year overall survival (OS) of 43% (95% CI: 34-52%) was significantly influenced by the karyotype: good 73%, intermediate 41%, and poor 18% (P=0.0001). These data suggest that the sequence of therapy employed is active in AML, but additional steps are needed to improve the outcome of patients with intermediate- and high-risk cytogenetic abnormalities.

The last decade has seen rapid evolution in the management of multiple myeloma. Cytogenetic, molecular, and proteomic techniques have led to a better understanding of the pathophysiology and prognostic markers of this heterogeneous malignancy. New immunomodulatory drugs, such as lenalidomide, which interrupt myeloma growth and survival pathways have entered into clinical usage. Combined with dexamethasone, oral lenalidomide has proved to be highly effective in patients whose disease has become resistant to conventional therapy. Currently, several clinical trials are ongoing in order to define the optimal use of this new agent and its combinations across the spectrum of patients with myeloma. Whether the ultimate outcome of future research will be a single-treatment solution for all patients, or whether treatments will become better-tailored to the individual (based on prognostic markers and pre-existing co-morbidities) has yet to be determined.

The incidence of venous thromboembolism (VTE) is more than 1 per thousand annually in the general population and increases further in cancer patients. The risk of VTE is higher in multiple myeloma (MM) patients who receive thalidomide or lenalidomide, especially in combination with dexamethasone or chemotherapy. Various VTE prophylaxis strategies, such as low-molecular-weight heparin (LMWH), warfarin or aspirin, have been investigated in small, uncontrolled clinical studies. This manuscript summarizes the available evidence and recommends a prophylaxis strategy according to a risk-assessment model. Individual risk factors for thrombosis associated with thalidomide/lenalidomide-based therapy include age, history of VTE, central venous catheter, comorbidities (infections, diabetes, cardiac disease), immobilization, surgery and inherited thrombophilia. Myeloma-related risk factors include diagnosis and hyperviscosity. VTE is very high in patients who receive high-dose dexamethasone, doxorubicin or multiagent chemotherapy in combination with thalidomide or lenalidomide, but not with bortezomib. The panel recommends aspirin for patients with < or = 1 risk factor for VTE. LMWH (equivalent to enoxaparin 40 mg per day) is recommended for those with two or more individual/myeloma-related risk factors. LMWH is also recommended for all patients receiving concurrent high-dose dexamethasone or doxorubicin. Full-dose warfarin targeting a therapeutic INR of 2-3 is an alternative to LMWH, although there are limited data in the literature with this strategy. In the absence of clear data from randomized studies as a foundation for recommendations, many of the following proposed strategies are the results of common sense or derive from the extrapolation of data from many studies not specifically designed to answer these questions. Further investigation is needed to define the best VTE prophylaxis.

Bortezomib (Velcade) is a boron containing molecule which reversibly inhibits the proteasome, an intracellular organelle which is central to the breakdown of ubiquinated proteins and consequently crucial for normal cellular homeostasis. Phase II clinical trials demonstrate it is effective for the treatment of relapsed refractory myeloma, and a phase III trial comparing bortezomib to dexamethasone in second/third line treatment showed superiority in progression free and overall survival. It is administered intravenously in the outpatient setting on days 1, 4, 8 and 11 of a 21-day cycle and regular monitoring for side effects is essential. It is currently approved for the treatment of multiple myeloma patients who have received at least one prior therapy and who have already undergone or are unsuitable for transplantation. Given the strength of this data the UK Myeloma Forum and British Committee for Standards in Haematology believe that bortezomib should be available for prescription by UK haematologists according to its licensed indication in patients with relapsed myeloma.

BACKGROUND:We have engaged in an international program designated the Bank On A Cure, which has established DNA banks from multiple cooperative and institutional clinical trials, and a platform for examining the association of genetic variations with disease risk and outcomes in multiple myeloma. We describe the development and content of a novel custom SNP panel that contains 3404 SNPs in 983 genes, representing cellular functions and pathways that may influence disease severity at diagnosis, toxicity, progression or other treatment outcomes. A systematic search of national databases was used to identify non-synonymous coding SNPs and SNPs within transcriptional regulatory regions. To explore SNP associations with PFS we compared SNP profiles of short term (less than 1 year, n = 70) versus long term progression-free survivors (greater than 3 years, n = 73) in two phase III clinical trials. RESULTS:Quality controls were established, demonstrating an accurate and robust screening panel for genetic variations, and some initial racial comparisons of allelic variation were done. A variety of analytical approaches, including machine learning tools for data mining and recursive partitioning analyses, demonstrated predictive value of the SNP panel in survival. While the entire SNP panel showed genotype predictive association with PFS, some SNP subsets were identified within drug response, cellular signaling and cell cycle genes. CONCLUSION/CONCLUSIONS:A targeted gene approach was undertaken to develop an SNP panel that can test for associations with clinical outcomes in myeloma. The initial analysis provided some predictive power, demonstrating that genetic variations in the myeloma patient population may influence PFS.

Multiple myeloma is the second most common haematological malignancy. It is becoming increasingly manageable with conventional and high-dose chemotherapy but there remains a critical need to develop both new drugs and combinations to improve long-term outcomes. Novel biological therapies that specifically target myeloma cells and/or their microenvironmental interactions are being developed that are highly effective, both as single agents and as combinations. Chief among these new agents are the proteasome inhibitor, bortezomib, and the immunomodulatory agents, thalidomide and lenalidomide. These drugs show improved single agent activity that is enhanced in combination. However, many drugs that are being developed in this setting may only have limited single agent activity, but combination use with these and other agents represents a very exciting way of targeting important pathogenic pathways crucial in myeloma development. This represents a challenge for both drug development and clinical trial evaluation, which has the potential to revolutionise the clinical management of myeloma and a paradigm for drug development in other diseases.

Members of the cystatin superfamily are involved in an inherited form of cerebral amyloid angiopathy and readily form amyloid fibrils in vitro. We have determined the structured core of human stefin B (cystatin B) amyloid fibrils using quenched hydrogen exchange and NMR. The core contains residues from four of the five strands of the native beta-sheet, delimited by unprotected loop regions analogous to those of the native monomeric structure. However, non-native features are also apparent, the most striking of which is the exclusion of the native alpha-helix. Before forming amyloid in vitro, cystatins dimerise via 3D domain swapping, and assemble into tetramers with trans to cis isomerism of a conserved proline. In the fibril, the hinge loop that forms an extended beta-structure in the dimer remains protected, consistent with the domain-swapping interface being maintained. However, the fibril data are not compatible with a simple 3D domain-swapping model for amyloid formation, and the displacement of the helix points to alternative packing arrangements of native-like beta-structure, in which proline isomerism is important in preventing steric clashing.