Todd M. Zimmerman

Initial genome sequencing and analysis of multiple myeloma

Multiple myeloma is an incurable malignancy of plasma cells, and its pathogenesis is poorly understood. Here we report the massively parallel sequencing of 38 tumour genomes and their comparison to matched normal DNAs. Several new and unexpected oncogenic mechanisms were suggested by the pattern of somatic mutation across the data set. These include the mutation of genes involved in protein translation (seen in nearly half of the patients), genes involved in histone methylation, and genes involved in blood coagulation. In addition, a broader than anticipated role of NF-κB signalling was indicated by mutations in 11 members of the NF-κB pathway. Of potential immediate clinical relevance, activating mutations of the kinase BRAF were observed in 4% of patients, suggesting the evaluation of BRAF inhibitors in multiple myeloma clinical trials. These results indicate that cancer genome sequencing of large collections of samples will yield new insights into cancer not anticipated by existing knowledge.

Widespread Genetic Heterogeneity in Multiple Myeloma: Implications for Targeted Therapy

We performed massively parallel sequencing of paired tumor/normal samples from 203 multiple myeloma (MM) patients and identified significantly mutated genes and copy number alterations and discovered putative tumor suppressor genes by determining homozygous deletions and loss of heterozygosity. We observed frequent mutations in KRAS (particularly in previously treated patients), NRAS, BRAF, FAM46C, TP53, and DIS3 (particularly in nonhyperdiploid MM). Mutations were often present in subclonal populations, and multiple mutations within the same pathway (e.g., KRAS, NRAS, and BRAF) were observed in the same patient. In vitro modeling predicts only partial treatment efficacy of targeting subclonal mutations, and even growth promotion of nonmutated subclones in some cases. These results emphasize the importance of heterogeneity analysis for treatment decisions.

Allogeneic Stem-Cell Transplantation of Renal Cell Cancer After Nonmyeloablative Chemotherapy: Feasibility, Engraftment, and Clinical Results

PURPOSE To evaluate the feasibility and safety of nonmyeloablative allogeneic stem-cell transplantation in patients with metastatic renal cell cancer (RCC) and to evaluate efficacy with respect to engraftment and tumor regression. PATIENTS AND METHODS Between February 1999 and June 2001, patients with refractory, metastatic RCC were screened for enrollment. A fludarabine and cyclophosphamide-based conditioning regimen was used. Patients received granulocyte-macrophage colony-stimulating factor-mobilized, unmanipulated stem cells from a 6/6 HLA-matched sibling donor. Prophylaxis against graft rejection and graft-versus-host disease (GVHD) included tacrolimus and mycophenolate mofetil. RESULTS A total of 284 patients with metastatic RCC were seen during this time period. Eighty-four patients who had siblings available for HLA typing were actively screened for enrollment, and 15 patients have undergone treatment. Durable donor engraftment was achieved in one of the first four patients treated. Patients no. 5 through 15 received a more immunosuppressive conditioning regimen, and all have achieved sustained donor engraftment. In the 12 patients with at least 180 days of follow-up, acute GVHD has occurred in two patients and chronic GVHD in six patients, with four transplant-related mortalities. Four partial responses have been observed (response rate, 33% in all patients; 44% in the nine patients with sustained donor engraftment). CONCLUSION Nonmyeloablative allogeneic stem-cell transplantation is feasible for a minority of patients with metastatic RCC. Adequately immunosuppressive conditioning is required for sustained donor engraftment, which is required for an antitumor response. Acute and chronic GVHD are the major causes of substantial morbidity and mortality. Metastatic RCC is susceptible to a graft-versus-tumor effect promoted by allogeneic stem-cell transplantation.

Phase I Trial of Anti-CS1 Monoclonal Antibody Elotuzumab in Combination With Bortezomib in the Treatment of Relapsed/Refractory Multiple Myeloma

PURPOSE To evaluate the maximum-tolerated dose (MTD), safety, and efficacy of elotuzumab in combination with bortezomib in patients with relapsed or relapsed and refractory multiple myeloma (MM). PATIENTS AND METHODS Elotuzumab (2.5, 5.0, 10, or 20 mg/kg intravenously [IV]) and bortezomib (1.3 mg/m(2) IV) were administered on days 1 and 11 and days 1, 4, 8, and 11, respectively, in 21-day cycles by using a 3 + 3 dose-escalation design. Patients with stable disease or better after four cycles could continue treatment until disease progression or unexpected toxicity. Responses were assessed during each cycle by using European Group for Blood and Marrow Transplantation (EBMT) criteria. RESULTS Twenty-eight patients with a median of two prior therapies were enrolled; three patients each received 2.5, 5.0, and 10 mg/kg of elotuzumab and 19 received 20 mg/kg (six during dose escalation and 13 during an expansion phase). No dose-limiting toxicities were observed during cycle 1 of the dose-escalation phase, and the MTD was not reached up to the maximum planned dose of 20 mg/kg. The most frequent grade 3 to 4 adverse events (AEs) were lymphopenia (25%) and fatigue (14%). Two elotuzumab-related serious AEs of chest pain and gastroenteritis occurred in one patient. An objective response (a partial response or better) was observed in 13 (48%) of 27 evaluable patients and in two (67%) of three patients refractory to bortezomib. Median time to progression was 9.46 months. CONCLUSION The combination of elotuzumab and bortezomib was generally well-tolerated and showed encouraging activity in patients with relapsed/refractory MM.

Fludarabine, Melphalan, and Alemtuzumab Conditioning in Adults With Standard-Risk Advanced Acute Myeloid Leukemia and Myelodysplastic Syndrome

PURPOSE This prospective phase II study evaluated toxicity, relapse rate, progression-free survival, and overall survival after allogeneic transplantation and conditioning with fludarabine, melphalan, and alemtuzumab in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). PATIENTS AND METHODS Fifty-two consecutive adults with AML and MDS were enrolled onto the study. Median age was 52 years (range, 17 to 71 years) and the majority of patients had high-risk disease, comorbidities, and/or modest reduction in performance status. Fifty-six percent of patients had unrelated or mismatched related donors. RESULTS After a median follow-up of 18 months (range, 2 to 34 months), 1-year survival was 48% (95% CI, 34% to 61%), progression-free survival was 38% (95% CI, 25% to 52%), relapse rate was 27% (95% CI, 15% to 40%), and treatment-related mortality was 33% (95% CI, 20% to 46%). The cumulative probability of extensive chronic graft-versus-host disease (GVHD) was only 18% (95% CI, 8% to 40%); extensive chronic GVHD was only observed in recipients of unrelated donor transplants. Performance score and disease status were the major predictors of outcome. High-risk disease (ie, active AML or MDS with > 5% blasts) or even modest decreases in performance status were associated with poor outcomes. Patients with standard-risk leukemia (first or second complete remission) or MDS (< 5% blasts) had excellent outcomes despite unfavorable disease characteristics. CONCLUSION Fludarabine and melphalan combined with in vivo alemtuzumab is a promising transplantation regimen for patients with AML or MDS and low tumor burden. For patients with active disease, this regimen provides at best modest palliation. Despite a low incidence of GVHD, transplantation is still associated with considerable nonrelapse mortality in patients with decreased performance status.

Phase 1 study of weekly dosing with the investigational oral proteasome inhibitor ixazomib in relapsed/refractory multiple myeloma

Proteasome inhibition is an effective treatment strategy for multiple myeloma. With improving survival, attention is increasingly focusing on ease of administration and toxicity profile. Ixazomib is an investigational, orally bioavailable 20S proteasome inhibitor. Sixty patients with relapsed and/or refractory multiple myeloma were enrolled on this phase 1 trial to evaluate safety and tolerability and determine the maximum tolerated dose (MTD) of single-agent, oral ixazomib given weekly for 3 of 4 weeks. Upon MTD determination, patients were enrolled to 4 different cohorts based on relapsed/refractory status and prior bortezomib and carfilzomib exposure. The MTD was determined to be 2.97 mg/m(2). Dose-limiting toxicities were grade 3 nausea, vomiting, and diarrhea in 2 patients, and grade 3 skin rash in 1 patient. Common drug-related adverse events were thrombocytopenia (43%), diarrhea (38%), nausea (38%), fatigue (37%), and vomiting (35%). The observed rate of peripheral neuropathy was 20%, with only 1 grade 3 event reported. Nine (18%) patients achieved a partial response or better, including 8 of 30 (27%) evaluable patients treated at the MTD. Pharmacokinetic studies suggested a long terminal half-life of 3.6 to 11.3 days, supporting once-weekly dosing. This trial was registered at www.clinicaltrials.gov as #NCT00963820.

Lenalidomide, bortezomib, pegylated liposomal doxorubicin, and dexamethasone in newly diagnosed multiple myeloma: a phase 1/2 Multiple Myeloma Research Consortium trial

This phase 1/2 trial evaluated combination lenalidomide, bortezomib, pegylated liposomal doxorubicin, and dexamethasone (RVDD) in newly diagnosed multiple myeloma (MM) patients. Patients received RVDD at 4 dose levels, including the maximum tolerated dose (MTD). Patients with a very good partial response or better (≥ VGPR) after cycle 4 proceeded to autologous stem cell transplantation or continued treatment. The primary objectives were MTD evaluation and response to RVDD after 4 and 8 cycles. Seventy-two patients received a median of 4.5 cycles. The MTDs were lenalidomide 25 mg, bortezomib 1.3 mg/m(2), pegylated liposomal doxorubicin 30 mg/m(2), and dexamethasone 20/10 mg, as established with 3-week cycles. The most common adverse events were fatigue, constipation, sensory neuropathy, and infection; there was no treatment-related mortality. Response rates after 4 and 8 cycles were 96% and 95% partial response or better, 57% and 65% ≥ VGPR, and 29% and 35% complete or near-complete response, respectively. After a median follow-up of 15.5 months, median progression-free survival (PFS) and overall survival (OS) were not reached. The estimated 18-month PFS and OS were 80.8% and 98.6%, respectively. RVDD was generally well tolerated and highly active, warranting further study in newly diagnosed MM patients. This trial was registered at www.clinicaltrials.gov as NCT00724568.

Outcomes of patients with AML and MDS who relapse or progress after reduced intensity allogeneic hematopoietic cell transplantation.

We describe treatment, outcomes and prognostic factors for patients who relapse following transplantation with a reduced intensity conditioning regimen. Seventy consecutive patients with high-risk myeloid malignancies underwent transplant and 25 (36%) relapsed, a median of 120 days later. The median percentage of bone marrow blasts at relapse was 24, the median donor chimerism was 73% and new karyotypic abnormalities occurred in 8 out of 20 (40%) evaluable patients. Twenty-one patients (84%) received aggressive treatment for relapse, including chemotherapy (60%), second hematopoietic cell transplantation (HCT; 52%) and/or donor lymphocyte infusion (DLI; 12%). Thirteen achieved a complete response (CR) and four remain in CR. Median overall survival (OS) after relapse was 6 months (95% confidence interval=2.7–9.9 months), and actuarial 1 year OS was 24%. Most deaths were due to disease progression (17/20, 85%). We did not observe an advantage for cellular therapy (DLI or second transplant) compared to chemotherapy. Salvage therapy for relapse after reduced intensity HCT is feasible, associated with low treatment-related mortality, and may result in prolonged survival in select patients. Studies exploring the optimal treatment for relapse following reduced intensity HCT are warranted.

Phase III randomised study of dexamethasone with or without oblimersen sodium for patients with advanced multiple myeloma

Upregulation of the Bcl-2 antiapoptotic protein is reported to be associated with aggressive clinical course in multiple myeloma. Oblimersen sodium is a bcl-2 antisense oligonucleotide complementary to the first six codons of the open-reading frame of bcl-2 mRNA that can decrease transcription of Bcl-2 protein and increase myeloma cell susceptibility to cytotoxic agents. In this phase III randomised trial, we investigated in patients with relapsed/refractory myeloma whether addition of oblimersen to dexamethasone improved clinical outcomes vs. dexamethasone alone. Two hundred and twenty-four patients were randomised to receive either oblimersen/dexamethasone (N = 110) or dexamethasone alone (N = 114). The primary endpoint was time to tumor progression (TTP). Final results of this study demonstrated no significant differences between the two groups in TTP or objective response rate. The oblimersen/dexamethasone regimen was generally well tolerated with fatigue, fever and nausea, the most common adverse events reported.

Identification of a novel microRNA cluster miR-193b-365 in multiple myeloma

There is accumulating evidence that the patterns of altered expression of microRNAs (miRNAs) correlate with distinct types of hematological malignancies. There is also emerging evidence for such miRNAs expression in multiple myeloma (MM), but the identity of the miRNAs that are abnormally expressed in this disease has not been elucidated. In the current study, we examined the miRNAs perturbed in CD138 positive MM cell lines and CD138 positive primary MM cells, using microarray analysis and quantitative real-time PCR. The expression levels in these cells were compared with the expression levels in CD138 positive plasma cells isolated from bone marrows of healthy donors. Our data demonstrate that multiple new miRNAs are commonly up-regulated and down-regulated including a new miRNA cluster, miR-193b-365, composed of two paralogs that were significantly up-regulated in MM. The organization and the sequences of the new miR-193b-365 cluster are highly conserved among vertebrates. Given that dysregulation of miR-193b-365 cluster has not been identified in other hematological malignancies examined to date, our findings suggest that miR-193b-365 cluster is part of the unique miRNA signature in MM.