Faculty Bibliography

To obtain a comprehensive genomic profile of presenting multiple myeloma cases we performed high-resolution single nucleotide polymorphism mapping array analysis in 114 samples alongside 258 samples analyzed by U133 Plus 2.0 expression array (Affymetrix). We examined DNA copy number alterations and loss of heterozygosity (LOH) to define the spectrum of minimally deleted regions in which relevant genes of interest can be found. The most frequent deletions are located at 1p (30%), 6q (33%), 8p (25%), 12p (15%), 13q (59%), 14q (39%), 16q (35%), 17p (7%), 20 (12%), and 22 (18%). In addition, copy number-neutral LOH, or uniparental disomy, was also prevalent on 1q (8%), 16q (9%), and X (20%), and was associated with regions of gain and loss. Based on fluorescence in situ hybridization and expression quartile analysis, genes of prognostic importance were found to be located at 1p (FAF1, CDKN2C), 1q (ANP32E), and 17p (TP53). In addition, we identified common homozygously deleted genes that have functions relevant to myeloma biology. Taken together, these analyses indicate that the crucial pathways in myeloma pathogenesis include the nuclear factor-κB pathway, apoptosis, cell-cycle regulation, Wnt signaling, and histone modifications. This study was registered at http://isrctn.org as ISRCTN68454111.

PURPOSE/OBJECTIVE:To identify the maximum-tolerated dose (MTD) and to evaluate the antileukemic activity of tosedostat (formerly CHR-2797), an orally bioavailable aminopeptidase inhibitor. PATIENTS AND METHODS/METHODS:In phase I, the MTD of once daily oral doses of tosedostat in hematologic malignancies was defined. In phase II, the therapeutic activity of the maximum-acceptable dose (MAD) of tosedostat was evaluated in elderly and/or relapsing patients with acute myeloid leukemia (AML) or myelodysplastic syndrome. RESULTS:In phase I, 16 patients were treated in four cohorts with tosedostat (60 mg to 180 mg) for 28 days. Three patients reported dose-limiting toxicities: two with reversible thrombocytopenia (> 75% reduction in platelet count) at 180 mg (MTD) and one with a Common Toxicity Criteria (CTC) grade 3 ALT elevation at 130 mg (MAD). In phase II, 41 patients were treated with 130 mg tosedostat. In phases I and II, the most common severe (CTC grades 3 to 5) adverse event was a reduction in the platelet count. Of the 51 AML patients in this study, seven reached complete marrow response (< 5% marrow blasts), with three achieving complete remission, and a further seven patients reaching a partial marrow response (between 5% and 15% marrow blasts). The overall response rate was therefore 27%. All responders were age > 60 years, and 79% had either relapsed or refractory AML. CONCLUSION/CONCLUSIONS:This phase I/II study demonstrates that oral once daily dosing with 130 mg tosedostat is well tolerated and has significant antileukemic activity. The favorable risk-benefit profile suggests that further clinical trials are warranted.

Bisphosphonates are firmly entrenched in the treatment of metastatic bone disease secondary to several tumor types, including breast cancer, prostate cancer, and myeloma. More recently, an emerging body of preclinical and clinical evidence indicates that bisphosphonates might also exhibit antitumor activity. This expanded role for bisphosphonates in the adjuvant setting might have profound clinical implications in many cancer types, particularly in the context of prevention of bone metastasis. Increased understanding of the mechanistic basis of the antitumor effects indicates that these might occur via direct mechanisms such as induction of apoptosis and inhibition of tumor cell adhesion and invasion, as well as indirect mechanisms such as inhibition of angiogenesis. There is also considerable evidence to suggest that nitrogen-containing bisphosphonates might exert additive or synergistic interactions with standard cytotoxic agents. However, mature clinical data with bisphosphonates are limited and, thus far, provide conflicting evidence regarding the antitumor role of bisphosphonates, but have mostly been conducted with first-generation bisphosphonates such as clodronate that are not as effective as next-generation bisphosphonates. Several large randomized clinical trials are ongoing with the next-generation bisphosphonate zoledronic acid to prospectively confirm an antitumor role for bisphosphonates in various tumor types. This review assesses the current body of preclinical and clinical evidence in favor of an antitumor effect of bisphosphonates in different cancer types.

We report the results of a Phase I/II dose escalation study to determine the maximum tolerated dose (MTD) of cyclophosphamide when combined with lenalidomide and dexamethasone in relapsed/refractory myeloma. Thirty-one patients were enrolled in cohorts of 3, at five dose levels of cyclophosphamide to a maximum of 700 mg on days 1 and 8 of a 28-d cycle. Patients received lenalidomide 25 mg days 1-21 and dexamethasone 20 mg orally days 1-4 and 8-11. The MTD was 600 mg cyclophosphamide, days 1 and 8. Grade 3/4 haematological complications occurred in 26% of patients, grade 3/4 infection in 3% (both at 700 mg cyclophosphamide), with thromboembolic complications in 6% of patients. Overall complete response (CR) rate was 29%, very good partial response rate 7% and partial response rate 45% giving an overall response rate of 81%. After 21 months median follow-up, projected 2-year progression-free survival was 56%, with 80% overall survival at 30 months. Ten further patients were treated at MTD with a 40% CR rate. No dose reductions for any study drugs or deaths occurred during cycles 1-9. Lenalidomide, cyclophosphamide and dexamethasone is a safe, effective combination in relapsed myeloma inducing a high response rate, warranting further investigation in phase III trials.

Thalidomide has received approval from the European Agency for the Evaluation of Medicinal Products for the treatment of newly diagnosed multiple myeloma (MM) patients older than 65 years or ineligible for transplant. The results of five phase III trials assessing thalidomide in combination with melphalan and prednisone (MPT) have demonstrated significantly improved response rates compared with melphalan and prednisone (MP) alone. Additionally, two of these studies showed that survival was extended by approximately 18 months in patients treated with MPT compared with MP alone. Thalidomide, in combination with MP, is associated with adverse events (AEs) including peripheral neuropathy and venous thromboembolism. In order to optimize the efficacy of MPT, a good awareness of these AEs is imperative. This manuscript outlines both evidence- and consensus-based recommendations discussed by a panel of experts, to provide a practical guide for physicians addressing the effective management of newly diagnosed, transplant-ineligible MM patients receiving thalidomide therapy.

Immunoglobulin production by myeloma plasma cells depends on the unfolded protein response for protein production and folding. Recent studies have highlighted the importance of IRE1alpha and X box binding protein 1 (XBP1), key members of this pathway, in normal B-plasma cell development. We have determined the gene expression levels of IRE1alpha, XBP1, XBP1UNSPLICED (XBP1u), and XBP1SPLICED (XBP1s) in a series of patients with myeloma and correlated findings with clinical outcome. We show that IRE1alpha and XBP1 are highly expressed and that patients with low XBP1s/u ratios have a significantly better overall survival. XBP1s is an independent prognostic marker and can be used with beta2 microglobulin and t(4;14) to identify a group of patients with a poor outcome. Furthermore, we show the beneficial therapeutic effects of thalidomide in patients with low XBP1s/u ratios. This study highlights the importance of XBP1 in myeloma and its significance as an independent prognostic marker and as a predictor of thalidomide response.

A large series of plasma cell dyscrasias (n=2207) was examined for translocations which deregulate the MAF genes, t(14;20)(q32;q12) and t(14;16)(q32;q23), and their disease behavior was compared to a group characterized by the t(4;14)(p16;q32) where CCND2 is also up-regulated. The t(14;20) showed low prevalence in myeloma (27/1830, 1.5%) and smoldering myeloma (1/148, <1%) with a higher incidence in MGUS (9/193, 5% P=0.005). Strong associations with del(13) (76%), non-hyperdiploidy (83%) and gain of 1q (58%) were seen but no association with an IgA M-protein or absence of bone disease was noted. All three translocations were associated with poor outcome in myeloma, but strikingly all t(14;20) MGUS/smoldering myeloma cases (n=10) had stable, low level disease. In contrast, the 10 t(14;16) and 25 t(4;14) MGUS/smoldering myeloma cases were associated with both evolving and non-evolving disease. None of the associated genetic abnormalities helped to predict for progression from MGUS or smoldering myeloma.