Faculty Bibliography

New effective strategies are required that specifically address the challenges of multiple myeloma (MM) treatment, namely, disease recurrence, immunosuppression, and treatment-related toxicities. Recent preclinical and clinical findings suggest that the IMiDs® immunomodulatory compound lenalidomide has a dual mechanism of action, involving both a direct tumoricidal activity and immunomodulation, which may result in rapid and sustained control of MM, respectively. The tumoricidal effect of lenalidomide occurs through several mechanisms, including disruption of stromal support, induction of tumor suppressor genes, and activation of caspases. The immunomodulatory effects of lenalidomide, including T-cell and natural killer (NK)-cell activation, and increased expression of death effector molecules, lead to enhanced immune cell function and may explain the beneficial effects of this agent in the maintenance setting. Lenalidomide appears to be effective regardless of prior thalidomide treatment, which may reflect mechanistic differences - lenalidomide has greater immunomodulatory properties than thalidomide, whereas thalidomide has greater antiangiogenic activity. Recent studies also suggest that the concomitant use of dexamethasone may influence lenalidomide's direct and immunomodulatory effects. Lenalidomide in combination with dexamethasone synergistically inhibits proliferation and induces apoptosis; however, dexamethasone appears to antagonize the immune-enhancing effect of lenalidomide. A study has demonstrated that a regimen of lenalidomide in combination with an optimal dose and schedule of dexamethasone may increase survival by allowing synergistic antiproliferative effects, without affecting immunomodulatory activity. As preclinical and clinical research continue, additional insights into the dual mechanism of action of lenalidomide will help to further optimize the use of lenalidomide in MM.

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.

Lytic bone disease is a frequent complication of multiple myeloma (MM). Lytic lesions rarely heal and X-rays are of limited value in monitoring bone destruction during anti-myeloma or anti-resorptive treatment. Biochemical markers of bone resorption (amino- and carboxy-terminal cross-linking telopeptide of type I collagen (NTX and CTX, respectively) or CTX generated by matrix metalloproteinases (ICTP)) and bone formation provide information on bone dynamics and reflect disease activity in bone. These markers have been investigated as tools for evaluating the extent of bone disease, risk of skeletal morbidity and response to anti-resorptive treatment in MM. Urinary NTX, serum CTX and serum ICTP are elevated in myeloma patients with osteolytic lesions and correlate with advanced disease stage. Furthermore, urinary NTX and serum ICTP correlate with risk for skeletal complications, disease progression and overall survival. Bone markers have also been used for the early diagnosis of bone lesions. This International Myeloma Working Group report summarizes the existing data for the role of bone markers in assessing the extent of MM bone disease and in monitoring bone turnover during anti-myeloma therapies and provides information on novel markers that may be of particular interest in the near future.

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.