A Prospective, Open-Label Safety and Efficacy Study of Combination Treatment with Bortezomib (PS-341, Velcade™) and Melphalan in Patients with Relapsed or Refractory Multiple Myeloma

Overview of drug therapy for multiple myeloma

Background. Multiple myeloma accounts for 10% of all haematologic malignancies worldwide. In Europe, over 10 000 new cases and nearly 8000 deaths were attributed to multiple myeloma in 2000. Unlike other malignancies, in which surgery and radiation are important treatment modalities, myeloma is exclusively treated with stem cell transplantation and drug therapy, requiring pharmacists to stay abreast of new developments. The melphalan-prednisolone and vincristine-doxorubicin-dexamethasone (VAD) regimens, which have been standard treatments for multiple myeloma over the past few decades, have yielded responses without real survival benefits. Transplantation utilizing high-dose chemotherapy has produced the only meaningful survival benefits for patients with multiple myeloma, but many patients are not candidates for this aggressive treatment option. More effective therapies for multiple myeloma are needed.

Objective. To address the mechanisms of action, safety, and efficacy of novel approaches to the treatment of myeloma involving bortezomib, thalidomide and its analogues, lenalidomide and CC-4047 (ActimidTM), and arsenic trioxide as single agents or in combination regimens.

Data sources. Published preclinical and primary clinical trial results, as well as scientific or clinical meeting abstracts. The author determined the relevance and subsequent inclusion of the data.

Conclusions. Bortezomib is approved in the US and Europe as single-agent therapy for the treatment of relapsed or refractory multiple myeloma. Thalidomide, its analogues, and arsenic trioxide have demonstrated activity and are under investigation in this disease. Further clinical trials of the efficacy and toxicity of these novel agents are ongoing and will further define optimal combinations and sequencing with conventional therapies.

Curcumin in combination with bortezomib synergistically induced apoptosis in human multiple myeloma U266 cells

Growth of multiple myeloma cells is controlled by various factors derived from host bone marrow microenvironments. Interaction between multiple myeloma cells and bone marrow stromal cells (BMSCs) plays an important role in the expression of adhesive molecules and secretion of growth factors involved in multiple myeloma (MM) cell growth, survival, and resistance to anticancer drugs. Recently, the possibility of developing novel anti-cancer therapeutic strategies targeting both MM cells and MM cell-BMSC interactions has been discussed. Here we present data showing that curcumin, a major constituent of turmeric compounds extracted from the rhizomes of the plant Curcuma longa, effectively reduced the growth of MM cells and BMSCs. Upon treatment with curcumin, IL-6/sIL-6R-induced STAT3 and Erk phosphorylation was dramatically reduced in the co-cultured cells. In addition, curcumin inhibited the production of pro-inflammatory cytokines and VEGF, factors that are associated with the progression of multiple myeloma, from both MM cells and BMSCs. In a combination treatment with curcumin and bortezomib, IL-6/sIL-6R-induced STAT3 and Erk phosphorylation was effectively inhibited. Moreover, this combination treatment synergistically inhibited the growth of MM cells co-cultured with BMSCs as compared to controls. Taken together, these results indicate that curcumin potentiates the therapeutic efficacy of bortezomib in MM suggesting this combination therapy to be of value in the clinical management of MM.

The therapeutic potential of the proteasome in leukaemia

Many cellular processes converge on the proteasome, and its key regulatory role is increasingly being recognized. Proteasome inhibition allows the manipulation of many cellular pathways including apoptotic and cell cycle mechanisms. The proteasome inhibitor bortezomib has enhanced responses in newly diagnosed patients with myeloma and provides a new line of therapy in relapsed and refractory patients. Malignant cells are more sensitive to proteasome inhibition than normal haematopoietic cells. Proteasome inhibition enhances many conventional therapies and its role in leukaemia is promising.

The pathogenesis of the bone disease of multiple myeloma

Multiple myeloma is a fatal hematologic malignancy associated with clonal expansion of malignant plasma cells within the bone marrow and the development of a destructive osteolytic bone disease. The principal cellular mechanisms involved in the development of myeloma bone disease are an increase in osteoclastic bone resorption, and a reduction in bone formation. Myeloma cells are found in close association with sites of active bone resorption, and the interactions between myeloma cells and other cells within the specialized bone marrow microenvironment are essential, both for tumor growth and the development of myeloma bone disease. This review discusses the many different factors which have been implicated in myeloma bone disease, including the evidence for their role in myeloma and subsequent therapeutic implications.

An open, randomized, controlled, phase II, single centre, two-period cross-over study to compare the quality of life and toxicity experienced on PEG interferon with interferon-α2b in patients with multiple myeloma maintained on a steady dose of interferon-α2b

PURPOSE

To compare the effects of pegylated interferon-alpha2b (P-IFN) and interferon-alpha2b (IFN) on quality of life (QoL) and toxicity in patients with multiple myeloma maintained on a steady dose of IFN.

PATIENTS AND METHODS

Consenting, eligible myeloma patients on IFN maintenance therapy for at least 6 weeks were randomly (1:1) allocated to receive P-IFN for 3 months followed by IFN for 3 months, or to continue with IFN for 3 months followed by P-IFN for 3 months (cross-over design). Patients were assessed for toxicity and QoL. Dose of P-IFN was equivalent to IFN.

RESULTS

The study enrolled 60 patients. At enrollment, 35 patients were in complete remission, 20 in partial remission and 5 were minimal responders. P-IFN was associated with significantly better global QoL score (mean difference 8.4; P = 0.0002). There was a significant improvement in functional scales--physical (P = 0.03), emotional (P = 0.04), social (P = 0.0008) with P-IFN. Fatigue (P = 0.0003), pain (P = 0.02) and appetite loss (P = 0.003) symptom scales were less in patients while on P-IFN. There were no statistically significant differences between treatment arms in QoL as measured by QLQ-MY24.

CONCLUSION

These data suggest that patients on P-IFN have a better QoL. Dose escalation studies are warranted to investigate potential impact on survival.

Phase I Trial of First-Line Bortezomib/Thalidomide plus Chemotherapy for Induction and Stem Cell Mobilization in Patients with Multiple Myeloma

BACKGROUND

In preclinical studies, bortezomib was shown to suppress tumor growth, sensitize malignant cells to apoptosis, and reverse chemotherapy resistance.

PATIENTS AND METHODS

We evaluated the addition of escalating doses of bortezomib 0.7, 1, and 1.3 mg/m2 intravenously on days 1, 4, and 8 to DT-PACE (cisplatin 10 mg/m2, doxorubicin 10 mg/m2, cyclophosphamide 400 mg/m2, and etoposide 40 mg/m2 per day by intravenous continuous infusion on days 1-4) plus oral dexamethasone 40 mg on days 1-4 and thalidomide 200 mg on days 1-8 in newly diagnosed patients with multiple myeloma. Peripheral blood stem cells were collected after cycle 1. Twelve patients completed the study, and all received autologous stem cell transplantation (SCT).

RESULTS

Hematologic toxicities were predictable, with 3 episodes of neutropenic fever. Grade >/= 2 nonhematologic toxicities included diarrhea (n = 1), deep vein thrombosis (n = 2), hypotension (n = 2), syncope (n = 1), and peripheral neuropathy (n = 3). The median number of CD34+ cells collected was 20.57 x 10 superset6 CD34+ cells/kg. After 2 cycles, 10 of 12 patients exhibited a partial response or better. Best response after autologous SCT, complete response/near complete response was exhibited in 9 patients, and partial response was exhibited in 3 patients. At a median of 20 months, 4 patients experienced relapse and 1 had died. Bortezomib/DT-PACE compared favorably with DT-PACE with regard to leukapheresis days, total CD34+ cell collection, and engraftment.

CONCLUSION

This novel strategy of simultaneous proteasome inhibition in combination with thalidomide and chemotherapy was effective and safe, allowing for adequate stem cell collection and early autologous SCT; its impact on overall survival, especially in patients with high-risk myeloma, awaits further investigation.

Bortezomib plus melphalan and prednisone in elderly untreated patients with multiple myeloma: results of a multicenter phase 1/2 study

Standard first-line treatment for elderly multiple myeloma (MM) patients ineligible for stem cell transplantation is melphalan plus prednisone (MP). However, complete responses (CRs) are rare. Bortezomib is active in patients with relapsed MM, including elderly patients. This phase 1/2 trial in 60 untreated MM patients aged at least 65 years (half older than 75 years) was designed to determine dosing, safety, and efficacy of bortezomib plus MP (VMP). VMP response rate was 89%, including 32% immunofixation-negative CRs, of whom half of the IF– CR patients analyzed achieved immunophenotypic remission (no detectable plasma cells at 10–4 to 10–5 sensitivity). VMP appeared to overcome the poor prognosis conferred by retinoblastoma gene deletion and IgH translocations. Results compare favorably with our historical control data for MP—notably, response rate (89% versus 42%), event-free survival at 16 months (83% versus 51%), and survival at 16 months (90% versus 62%). Side effects were predictable and manageable; principal toxicities were hematologic, gastrointestinal, and peripheral neuropathy and were more evident during early cycles and in patients aged 75 years or more. In conclusion, in elderly patients ineligible for transplantation, the combination of bortezomib plus MP appears significantly superior to MP, producing very high CR rates, including immunophenotypic CRs, even in patients with poor prognostic features.

Advances in the management of myeloma bone disease

Multiple myeloma is the second most common adult haematological malignancy. One of the major clinical features is the development of a unique osteolytic bone disease, characterised by progressive and devastating bone destruction, bone pain, pathological fractures and hypercalcaemia. Bisphosphonates, inhibitors of osteoclastic bone resorption, are the standard therapy for myeloma-induced bone disease. However, as our understanding of the molecular mechanisms involved in the development of myeloma bone disease increases, new molecular targets have been identified for the treatment of this devastating bone disease.

Proteasome inhibition: novel therapy for multiple myeloma

Therapeutic options for patients with myeloma are a rapidly advancing area of research due in part to an increase in the understanding of myeloma biology as well as the development of novels agents. Proteasome inhibition is a novel modality for the treatment of patients with myeloma. Bortezomib, a novel proteasome inhibitor, was effective in a broad range of tumor cell lines in preclinical testing. In phase I trials, bortezomib was noted to be active in patients with multiple myeloma and lymphoma. This led to several multicenter trials confirming the safety and efficacy of bortezomib for patients with relapsed and refractory myeloma. Most recently, a large randomized phase III trial comparing bortezomib with high-dose dexamethasone demonstrated that bortezomib had an improved response rate, duration of remission and overall survival advantage in the setting of relapsed disease. These findings have led investigators to study proteasome inhibition with conventional chemotherapy and other novel agents. In addition, several recently completed and ongoing studies are evaluating the role of bortezomib in the initial treatment of myeloma. The success of proteasome inhibition in the treatment of myeloma is a model for effective translation of preclinical research into tangible clinical benefits for patients with cancer.

Phase I/II trial assessing bortezomib and melphalan combination therapy for the treatment of patients with relapsed or refractory multiple myeloma

PURPOSE

Bortezomib has shown synergy with melphalan in preclinical models. We assessed the safety, tolerability, and response rate in a dose-escalation study of this combination for relapsed or refractory multiple myeloma patients.

METHODS

Bortezomib was administered from 0.7 to 1.0 mg/m(2) on days 1, 4, 8, and 11 of a 28-day cycle for up to eight cycles. Oral melphalan was administered in escalating doses from 0.025 to 0.25 mg/kg on days 1 to 4.

RESULTS

Thirty-five patients with relapsed or refractory myeloma were enrolled, 34 of whom were assessable for response. Dose-limiting toxicity of grade 4 neutropenia in two of six patients in the highest dose cohort led to the assignment of bortezomib 1.0 mg/m2 and melphalan 0.10 mg/kg as the maximum-tolerated dose (MTD). Responses (minimal [MR], partial [PR], or complete [CR]) occurred in 23 of 34 patients (68%), including two CRs (6%), three immunofixation-positive CRs (9%), 11 PRs (32%), and seven MRs (21%). Responses were observed in five of six assessable patients (83%) at the MTD. Median progression-free survival for all patients was 8 months (range, 2 to 18 months). Grade > or = 3 toxicities were related mostly to myelosuppression. Among the 15 patients with grade 1/2 neuropathy at baseline, it resolved during treatment in one, worsened in four, and remained stable in 10 patients. Eight other patients developed grade 1/2 neuropathy during the study.

CONCLUSION

Bortezomib plus melphalan given on a 28-day schedule showed encouraging activity with manageable toxicity and represents a promising treatment for myeloma patients.

Novel Treatment Approaches for Patients with Multiple Myeloma

Treatment options for patients with multiple myeloma are a rapidly progressing area of clinical and scientific development. The discovery of key signaling pathways needed for myeloma cell growth and proliferation has resulted in a plethora of new and different treatment options. Chief among these new agents are the proteasome inhibitor bortezomib and the immunomodulatory agents thalidomide and lenalidomide. Efficacy for these agents has been extensively studied in the relapsed and refractory states, and more recently in induction therapy. Impressive responses have been observed in the induction and relapsed disease states, completely changing the disease treatment paradigms. Building on these successes and strong preclinical work, other signal transduction inhibitors are being tested in phase I and phase II clinical trials. These include agents that target histone acetylation, farnesylation, heat shock proteins, and direct AKT-targeting agents. Additionally, monoclonal antibody targets are being developed in an effort to target the tumor cells extracellularly. Clinical trial development based on preclinically designed rational combinations and targets have the potential to rapidly translate these findings into meaningful clinical responses.

The combination of the farnesyl transferase inhibitor lonafarnib and the proteasome inhibitor bortezomib induces synergistic apoptosis in human myeloma cells that is associated with down-regulation of p-AKT

The identification of signaling pathways critical to myeloma growth and progression has yielded an array of novel agents with clinical activity. Multiple myeloma (MM) growth is IL-6 dependent, and IL-6 is secreted in an autocrine/paracrine fashion with signaling via the Ras/Raf/mitogen-activated protein kinase (MAPK) pathway. We hypothesized that combining a Ras pathway inhibitor (lonafarnib, SCH66336) with a proteasome inhibitor (bortezomib, Velcade, PS-341) would enhance myeloma-cell killing. MM cell lines and primary human cells were used to test either single agent bortezomib, lonafarnib, or the combination on MM signaling and apoptosis. Combination therapy induced synergistic tumor-cell death in MM cell lines and primary MM plasma cells. Cell death was rapid and associated with increased caspase 3, 8, and 9 cleavage and concomitant down-regulation of p-AKT. Down-regulation of p-AKT was seen only in combination therapy and not seen with either single agent. Cells transfected with constitutively active p-AKT, wild-type AKT, or Bcl-2 continued to demonstrate synergistic cell death in response to the combination. The order of addition was critically important, supporting bortezomib followed by lonafarnib as the optimal schedule. The combination of a proteasome inhibitor and farnesyl transferase inhibitor demonstrates synergistic myeloma-cell death and warrants further preclinical and clinical studies.

Gene expression profiling and multiple myeloma

Gene expression profiling is a powerful tool through which the biology of multiple myeloma can be dissected. We will describe in this chapter how early studies using this technology have provided meaningful insights into myeloma biology, have led to the identification of new therapeutic targets, and have identified powerful prognostic and pharmacogenomic markers. Specifically, we will demonstrate that gene expression profiling can be used to segregate myeloma patients into prognostic categories within which known IgH translocation signatures can be readily defined. We also show that expression signatures can identify patients with chromosome 13 deletion. Finally, we demonstrate that global gene expression signatures can be distilled to short lists of three genes or more which together impart clinical outcome information, which is significantly more powerful than any previously defined prognostic tool. Expression profiling has also led to the identification of a number of new therapeutic targets not only in myeloma cell survival but also in the pathogenesis of the osteolysis which is a hallmark of this disease.

Targeted therapy for haematological malignancies: clinical update from the American Society of Hematology, 2004

Recent advances in the treatment and management of haematological malignancies are due in large part to an improved understanding of the basic biology that drives tumour cell growth and survival. This improved understanding has led to the clinical study and approval of a number of different targeted agents across a number of different haematological tumours. This review of clinical data covers some of the exciting clinical advances that were reported at the recent American Society of Hematology meeting in San Diego, USA. This paper focuses on three important areas of biological research that has yielded clinical trials that have affected clinical outcomes. The areas covered include proteasome inhibition and myeloma, tyrosine kinase inhibitors that are directed at the BCR-ABL fusion protein and chronic myeloid leukaemia/acute lymphoblastic leukaemia, and FLT3 inhibitors and acute myeloid leukaemia acute lymphoblastic leukaemia therapy.

Advances in myeloma genetics and prospects for pharmacogenomic testing in multiple myeloma

Pharmacogenomic studies in multiple myeloma, a neoplasia of clonally expanded malignant bone marrow plasma cells, are helping to set the stage for individualized therapy. Although relatively few in numbers, these studies are already providing new therapeutic targets and avenues for drug discoveries as well as contributing to novel prognostic markers in multiple myeloma. High-throughput mutation screening of the kinome promises to identify further novel targets for therapy. Genetics and gene expression profiling technology have improved molecular-based patient stratification and prognostic staging, expanded knowledge of the molecular mechanism of chemotherapeutic agents, and provided a better understanding of myeloma bone disease. The use of pharmacogenomic strategies in myeloma is thus already changing medical practice.

Multiple myeloma: The role of transplant and novel treatment strategies

Multiple myeloma will be diagnosed in over 14,000 new patients over the next year. While myeloma is rarely curable, recent advances have improved the care and outlook for most patients. Recent progress has been made on the molecular characterization of myeloma, cytogenetics, prognosis, and supportive care. Randomized trials have proven the efficacy of high-dose therapy supported by autologous transplantation. Reduced-intensity allogeneic transplantation, associated with much less morbidity and mortality than standard myeloablative transplantation, can now be offered to more myeloma patients. And finally, a greater understanding of the pathophysiology of myeloma development and progression, growth, and survival have led to the development and clinical use of several novel therapeutics. This review will discuss recent improvements in therapies for myeloma focusing on transplantation and novel targeted therapies.

Update on the Proteasome Inhibitor Bortezomibin Hematologic Malignancies

The ubiquitin-proteasome system plays a crucial role in eukaryotic cells in maintaining protein homeostasis. Through the disruption of a variety of pathways and cell cycle checkpoints, proteasome inhibition leads to apoptosis and in experimental models can overcome chemoresistance. Bortezomib is the first of its class of proteasome inhibitors tested in humans that showed promising activity in several tumor types, and especially in hematologic malignancies, in phase I studies. The remarkable results obtained in phase II studies in multiple myeloma (MM) led to its fast-track approval by the US Food and Drug Administration in May 2003 for relapsed MM. More recent observation also revealed promising activity in non-Hodgkin's lymphoma. This review will explore the rationale for the use of bortezomib in hematologic malignancies as well as provide an update on the results of ongoing studies and future directions for the use of this new agent in hematologic malignancies. The mechanism of action of bortezomib and its nonoverlapping toxicity profile make it a very appealing drug for combination with other chemotherapeutic or biologic agents. Bortezomib represents an excellent example of how progress in understanding the biology of cancer cells can impact clinical practice and lead toward a new era of rational therapeutics.