Randomized phase III study of pegylated liposomal doxorubicin plus bortezomib compared with bortezomib alone in relapsed or refractory multiple myeloma: combination therapy improves time to progression

Clinical and investigational use of proteasome inhibitors for transplant rejection

INTRODUCTION

The presence of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) in patients experiencing acute cellular rejection and antibody-mediated rejection (AMR) is associated with poor renal allograft survival in kidney transplant recipients. Traditional therapies for AMR provide variable results, and do not deplete the cellular source of antibody production, that is, the plasma cell.

AREAS COVERED

Physiologic effects of proteasome inhibitors (PIs) are reviewed in the context of recent clinical reports of PI therapy in solid organ transplantation for AMR and desensitization.

EXPERT OPINION

PI-based therapy is a novel approach for treating AMR that is being employed with increasing frequency in transplantation. Initial reports of PI-based regimens for treating AMR have demonstrated the ability of bortezomib to significantly reduce DSA levels and improve histology and allograft function. Use of PI agents have recently been evaluated in a large multicenter collaborative consisting of over 100 solid organ transplant recipients treated with a common PI-based regimen. Increasing experience with PI-based regimens for AMR have indicated that PI therapy (similar to other AMR therapies) provides excellent results in early AMR, with late AMR demonstrating a greater degree of therapeutic resistance. A substantial number of strategies exist for enhancement of therapeutic results with PI therapy for AMR.

Approach to the treatment of multiple myeloma: a clash of philosophies

In this Perspective, we summarize some of the most contentious issues surrounding diagnosis and treatment of myeloma. We outline how a fundamental clash of philosophies, cure versus control, may be at the heart of many of the controversies. From the very definition of the disease to risk stratification to the validity of current clinical trial endpoints, we highlight the major areas of debate and provide alternative viewpoints that have implications for trial design and interpretation, as well as clinical practice.

Treatment options for relapsed and refractory multiple myeloma

Treatment options for patients with relapsed myeloma have benefited from the development of new targeted agents. The use of bortezomib, thalidomide, and lenalidomide have dramatically changed outcomes for patients with relapsed myeloma. New agents are also in development, on the basis of preclinical rationale, as well as combinations of conventional and novel agents. Together each of these treatment approaches are being tested in phase I, II, and III clinical trials, with the goal of prolonged duration of remission and, ultimately, improved overall survival.

Oncogenomics to target myeloma in the bone marrow microenvironment

Multiple myeloma (MM) is an example of rapid bench-to-bedside translation in new drug development. Bortezomib and lenalidamide target the tumor cell in the bone marrow microenvironment to overcome drug resistance in laboratory and animal models; each is effective to treat relapsed and/or refractory, relapsed, and newly diagnosed MM, and both are now showing promise as maintenance therapy. Major ongoing translational research efforts include improved classification and personalized therapies; identification and validation of next-generation agents targeting the tumor cell in its microenvironment; novel immune therapies; rationally based combination therapies; and use of novel agents to delay or prevent development of active MM. This paradigm of targeting the tumor in its microenvironment has already extended median survival in MM from 3 to 7 to 8 years and has great potential to improve patient outcome in other hematologic malignancies and solid tumors as well.

Bortezomib as the first proteasome inhibitor anticancer drug: current status and future perspectives

Targeting the ubiquitin-proteasome pathway has emerged as a rational approach in the treatment of human cancer. Based on positive preclinical and clinical studies, bortezomib was subsequently approved for the clinical use as a front-line treatment for newly diagnosed multiple myeloma patients and for the treatment of relapsed/refractory multiple myeloma and mantle cell lymphoma, for which this drug has become the staple of treatment. The approval of bortezomib by the US Food and Drug Administration (FDA) represented a significant milestone as the first proteasome inhibitor to be implemented in the treatment of malignant disease. Bortezomib has shown a positive clinical benefit either alone or as a part of combination therapy to induce chemo-/radio-sensitization or overcome drug resistance. One of the major mechanisms of bortezomib associated with its anticancer activity is through upregulation of NOXA, which is a proapoptotic protein, and NOXA may interact with the anti-apoptotic proteins of Bcl-2 subfamily Bcl-X(L) and Bcl-2, and result in apoptotic cell death in malignant cells. Another important mechanism of bortezomib is through suppression of the NF-κB signaling pathway resulting in the down-regulation of its anti-apoptotic target genes. Although the majority of success achieved with bortezomib has been in hematological malignancies, its effect toward solid tumors has been less than encouraging. Additionally, the widespread clinical use of bortezomib continues to be hampered by the appearance of dose-limiting toxicities, drug-resistance and interference by some natural compounds. These findings could help guide physicians in refining the clinical use of bortezomib, and encourage basic scientists to generate next generation proteasome inhibitors that broaden the spectrum of efficacy and produce a more durable clinical response in cancer patients. Other desirable applications for the use of proteasome inhibitors include the development of inhibitors against specific E3 ligases, which act at an early step in the ubiquitin-proteasome pathway, and the discovery of less toxic and novel proteasome inhibitors from natural products and traditional medicines, which may provide more viable drug candidates for cancer chemoprevention and the treatment of cancer patients in the future.

Novel drugs in myeloma: harnessing tumour biology to treat myeloma

Steroids and alkylating agents have formed the backbone of myeloma therapy for decades with the result that patient outcomes improved very little over this period. The situation has changed recently with the advent of immunomodulatory agents and bortezomib, and patient outcomes are now improving. The introduction of bortezomib can be viewed as particularly successful as it was designed in the laboratory to fit a target that had been identified through biological research. As such, it has formed the template for new drug discovery in myeloma, with an increased understanding of the biology of the myeloma cell leading to the definition of upregulated pathways which are then targeted with a specific agent. This chapter will examine novel agents currently in development in the context of the abnormal biology of the myeloma cell and its microenvironment.

Management of relapsed or refractory multiple myeloma in French hospitals and estimation of associated direct costs: a multi-centre retrospective cohort study

WHAT IS KNOWN AND BACKGROUND

 For relapsed or refractory multiple myeloma (RRMM), a series of novel agents (thalidomide, bortezomib and lenalidomide) has emerged during the latest decade, but their use in routine clinical practice is not well documented as well as the cost of RRMM.

OBJECTIVE

Our aim is to review the therapeutic management of such patients in France and to estimate the associated costs.

METHODS

A retrospective cohort study, based on chart reviews, was conducted in French Haematology Departments over the period 2004-2007 and the associated direct costs estimated.

RESULTS

One hundred and two patients with a relapse after first-line therapy were selected from five centres. The average follow-up from diagnosis or the date of first relapse to death or to the latest news was respectively 56.25 and 23.53 months. Novel agents were used in 73% of all cases, and in all cases of first relapse. Thalidomide and bortezomib were respectively the most frequently used second-line (57%) and third-line treatments (44%). The average number of lines of treatment received per patient as from first relapse was 2.75 (min 1; max 8) and the mean direct cost per month was estimated at 3130 € after the first relapse. This cost was represented in greater part by the cost of chemotherapy drugs (66%).

WHAT IS NEW AND CONCLUSION

The use of novel agents such as thalidomide, bortezomib and lenalidomide for RRMM is highly prevalent in France from the first relapse. The associated medical cost is substantial mainly due to the cost of the new agents.

Cardiotoxicity of anticancer treatments: what the cardiologist needs to know

Cardiotoxicity of anticancer treatments has become an increasingly important clinical problem faced by cardiologists. Left ventricular systolic dysfunction and heart failure generate the most concern, but clinical features and prognosis vary considerably depending on the causative agent. Anthracycline-related cardiomyopathy differs fundamentally from effects associated with newer targeted agents, such as trastuzumab. Other forms of cardiovascular disease that occur as a result of cancer treatment include hypertension, thromboembolic disease, pericardial disease, arrhythmia, and myocardial ischemia. The approach to cardiovascular disease in patients with cancer is often different from that in the general population, not only because of distinct underlying mechanisms and clinical features of their heart disease, but also because of the potential ongoing need for additional cancer treatment as well as the altered duration of anticipated survival. In an effort to maximize both quality of life and survival, cardiologists and oncologists should collaborate with the aim of balancing the risks of cardiotoxicity with the benefits of oncologic therapy.

Nanoscale Drug Delivery and Hyperthermia: The Materials Design and Preclinical and Clinical Testing of Low Temperature-Sensitive Liposomes Used in Combination with Mild Hyperthermia in the Treatment of Local Cancer

The overall objective of liposomal drug delivery is to selectively target drug delivery to diseased tissue, while minimizing drug delivery to critical normal tissues. The purpose of this review is to provide an overview of temperature-sensitive liposomes in general and the Low Temperature-Sensitive Liposome (LTSL) in particular. We give a brief description of the material design of LTSL and highlight the likely mechanism behind temperature-triggered drug release. A complete review of the progress and results of the latest preclinical and clinical studies that demonstrate enhanced drug delivery with the combined treatment of hyperthermia and liposomes is provided as well as a clinical perspective on cancers that would benefit from hyperthermia as an adjuvant treatment for temperature-triggered chemotherapeutics. This review discusses the ideas, goals, and processes behind temperature-sensitive liposome development in the laboratory to the current use in preclinical and clinical settings.

Targeting autophagy augments in vitro and in vivo antimyeloma activity of DNA-damaging chemotherapy

PURPOSE

Although autophagy occurs in most tumor cells following DNA damage, it is still a mystery how this DNA-damaging event turns on the autophagy machinery in multiple myeloma (MM) and how the functional status of autophagy impacts on its susceptibility to death in response to DNA-damaging chemotherapy.

EXPERIMENTAL DESIGN

We investigate the effects of DNA damage on autophagy in MM cells and elucidate its underlying molecular mechanism. Then, we examined the impacts of pharmacologic or genetic inhibition of autophagy on DNA damage-induced apoptosis. Furthermore, the antimyeloma activity of autophagy inhibitor in combination with DNA-damaging agents was evaluated in MM xenograft models.

RESULTS

We showed that DNA-damaging drugs, doxorubicin and melphalan, induce caspase-dependent apoptosis and concurrently trigger Beclin 1-regulated autophagy in human MM cell lines H929 and RPMI 8226. Mechanistically, association of autophagy execution proteins Beclin 1 with class III phosphoinositide 3-kinase, which is inhibited by Bcl-2 recruitment, contributes directly to the autophagic process. Importantly, targeting suppression of autophagy by minimally toxic concentrations of pharmacologic inhibitors (hydroxychloroquine and 3-methyladenine) or short hairpin RNAs against autophagy genes, Beclin 1 and Atg5, dramatically augments proapoptotic activity of DNA-damaging chemotherapy both in vitro using MM cell lines or purified patient MM cells and in vivo in a human plasmacytoma xenograft mouse model.

CONCLUSION

These data can help unravel the underlying molecular mechanism of autophagy in DNA-damaged MM cells and also provide a rationale for clinical evaluation of autophagy inhibitors in combination with DNA-damaging chemotherapy in MM.

Future directions of next-generation novel therapies, combination approaches, and the development of personalized medicine in myeloma

Despite tangible progress in recent years, substantial therapeutic challenges remain in multiple myeloma (MM), particularly for patients at high risk for early relapse or death and for those with advanced multi-drug resistant disease and refractoriness to currently available combination regimens. Addressing these challenges requires identification of novel classes of anti-MM agents, their incorporation into safe and more effective combination regimens, and development of efficient algorithms to select the most appropriate therapeutic options for the clinical and molecular features of individual patients at a given time during their disease. Ideally, these goals can be facilitated by preclinical identification of the "driver" molecular lesions on which different myeloma subtypes exquisitely depend, and by informative preclinical models simulating the clinical setting(s) in which trials will be conducted. Large prospective studies of patients treated uniformly with contemporary clinical regimens are essential, but there is also a major need for flexibility in studying new regimens in the future. Long-term patient follow-up and integrated annotation of clinical (safety and efficacy) and correlative (molecular, biochemical, etc) data are also critical. Novel molecular profiling techniques will likely identify more clinically and biologically discrete subsets of patients with recurrent, even if infrequent, lesions. This molecular heterogeneity, combined with the increasing numbers of candidate therapeutic targets and respective investigational agents, may pose formidable challenges for the development and implementation of personalized medicine in MM. This review discusses these challenges, as well as potential strategies to address them, with the aim of making significant improvement in the clinical outcome of patients with MM.

A steroid-independent regimen of bortezomib, liposomal doxorubicin and thalidomide demonstrate high response rates in newly diagnosed multiple myeloma patients

Novel agents have provided a new foundation for multiple myeloma therapies. When combined with other anti-myeloma agents, these compounds significantly enhance clinical efficacy. High-dose steroids are frequently used in anti-myeloma combination regimens; however, the doses employed are often poorly tolerated, especially in patients with concurrent comorbid conditions. We hypothesized that a steroid-independent combination regimen could be developed without significant compromise of efficacy. The availability of such a regimen will be important for patients whose concurrent ailments make them poor candidates for steroid containing anti-myeloma regimens. A phase II single institute, non-randomized clinical trial was conducted to investigate a novel steroid-free three-drug combination of bortezomib (V), pegylated liposomal doxorubicin (D), and thalidomide (T), the VDT regimen. Forty-three newly diagnosed multiple myeloma patients requiring treatment were enrolled on this study. The overall response rate and complete response (CR) + near complete response (nCR) rate was 78% and 35%, respectively. Median time to progression was 29·5 months. Fatigue, rash, neuropathy, constipation and infections were the most common side effects. We concluded that VDT is a tolerable and an effective regimen capable of inducing high response rates and can be employed in patients considered to be poor candidates for steroid-based treatment regimens.

Tanespimycin and bortezomib combination treatment in patients with relapsed or relapsed and refractory multiple myeloma: results of a phase 1/2 study

This open-label, dose escalation, multicentre phase 1/2 trial was undertaken to determine the safety and tolerability of the heat shock protein 90 (HSP90) inhibitor tanespimycin (100-340 mg/m(2) )+ bortezomib (0·7-1·3 mg/m(2) ) given on days 1, 4, 8 and 11 in each 21-d cycle. Phase 2 expansion occurred at the highest tested dose of tanespimycin at 340 mg/m(2) and bortezomib at 1·3 mg/m(2) . Seventy-two patients (median age, 60 years) with relapsed or relapsed and refractory multiple myeloma (MM) were enrolled; 63 patients (89%) completed the study. Tanespimycin in combination with bortezomib was well tolerated; few patients experienced significant neutropenia, constipation and anorexia (<10%), and no patients developed severe peripheral neuropathy. Among 67 efficacy-evaluable patients, there were 2 (3%) complete responses and 8 (12%) partial responses, for an objective response rate (ORR) of 27%, including 8 (12%) minimal responses. Response rates were highest among bortezomib-naive patients and proved durable in all patient subgroups, including those with bortezomib-refractory disease. Pharmacodynamic analyses indicated that tanespimycin plus bortezomib effectively inhibited the proteasome, as evidenced by decreased 20S proteasome activity, and inhibited HSP90, as reflected by increased HSP70 expression. The results of this study support additional studies of this combination approach in MM.

Subcutaneous versus intravenous administration of bortezomib in patients with relapsed multiple myeloma: a randomised, phase 3, non-inferiority study

BACKGROUND

Intravenous injection is the standard administration route of bortezomib; however, subcutaneous administration is an important alternative. We compared the efficacy and safety of subcutaneous versus intravenous bortezomib at the approved 1·3 mg/m(2) dose and twice per week schedule in patients with relapsed multiple myeloma.

METHODS

This randomised, phase 3 study was undertaken at 53 centres in ten countries in Europe, Asia, and South America. Patients aged 18 years and older with relapsed multiple myeloma after one to three previous lines of therapy were randomly assigned to receive up to eight 21-day cycles of bortezomib 1·3 mg/m(2), on days 1, 4, 8, and 11, by subcutaneous injection or intravenous infusion. Randomisation was by an interactive voice response system based on a computer-generated randomisation schedule, stratified by number of previous lines and disease stage. Patients and treating physicians were not masked to treatment allocation. The primary objective was to show non-inferiority of subcutaneous versus intravenous bortezomib in terms of overall response rate (ORR) after four cycles in all patients with a diagnosis of measurable, secretory multiple myeloma who received one or more dose of drug (response-evaluable population). Non-inferiority was defined as retaining 60% of the intravenous treatment effect. This study is registered with ClinicalTrials.gov, number NCT00722566, and is ongoing for long-term follow-up.

FINDINGS

222 patients were randomly assigned to receive subcutaneous (n=148) or intravenous (n=74) bortezomib. The response-evaluable population consisted of 145 patients in the subcutaneous group and 73 in the intravenous group. Patients received a median of eight cycles (range one to ten) in both groups. ORR after four cycles was 42% in both groups (61 patients in subcutaneous group and 31 in intravenous group; ORR difference -0·4%, 95% CI -14·3 to 13·5), showing non-inferiority (p=0·002). After a median follow-up of 11·8 months (IQR 7·9-16·8) in the subcutaneous group and 12·0 months (8·1-15·6) in the intravenous group, there were no significant differences in time to progression (median 10·4 months, 95% CI 8·5-11·7, vs 9·4 months, 7·6-10·6; p=0·387) and 1-year overall survival (72·6%, 95% CI 63·1-80·0, vs 76·7%, 64·1-85·4; p=0·504) with subcutaneous versus intravenous bortezomib. Grade 3 or worse adverse events were reported in 84 (57%) patients in the subcutaneous group versus 52 (70%) in the intravenous group; the most common were thrombocytopenia (19 [13%] vs 14 [19%]), neutropenia (26 [18%] vs 13 [18%]), and anaemia (18 [12%] vs six [8%]). Peripheral neuropathy of any grade (56 [38%] vs 39 [53%]; p=0·044), grade 2 or worse (35 [24%] vs 30 [41%]; p=0·012), and grade 3 or worse (nine [6%] vs 12 [16%]; p=0·026) was significantly less common with subcutaneous than with intravenous administration. Subcutaneous administration was locally well tolerated.

INTERPRETATION

Subcutaneous bortezomib offers non-inferior efficacy to standard intravenous administration, with an improved safety profile.

FUNDING

Johnson & Johnson Pharmaceutical Research and Development, and Millennium Pharmaceuticals.

How to treat patients with relapsed/refractory multiple myeloma: evidence-based information and opinions

INTRODUCTION

Relapsed/refractory multiple myeloma (rrMM) remains a difficult condition to treat despite the availability of new drugs. This review aims to provide evidence to guide physicians in the choice of salvage therapy in certain subgroups of patients.

AREAS COVERED

The review attempts to present evidence-based information and suggest possible approaches based on data on previous therapies, previous remission duration and toxicity of previous treatments, patient's co-morbidities and disease characteristics at relapse. Unfortunately, little evidence is available; there are no large and/or randomized trials, direct comparisons of drugs or combinations for rrMM patients to draw any definite conclusion.

EXPERT OPINION

Almost all the studies presented here suggest that depth of response is a key factor also for patients with rrMM. Identifying the best approach between combinations and sequential therapies remains controversial. Several studies favor the former approach in early relapse as it leads to a higher complete response rate, regardless of previous therapies. However, in both strategies, achieving maximal response should always remain a main goal. Consolidation/maintenance therapy is beneficial both in combination and sequential therapies also in rrMM. Second generation new drugs, such as pomalidomide, carfilzomib, bendamustine and HDAC inhibitors, will probably expand the rescue possibilities also in this setting.

The role of bortezomib, thalidomide and lenalidomide in the management of multiple myeloma: an overview of clinical and economic information

Bortezomib, thalidomide and lenalidomide can be aimed at treating patients with newly diagnosed multiple myeloma (both eligible and ineligible for transplantation) as well as those with relapsed or refractory disease. This review analysed the available clinical and economic data on these three drugs. Irrespective of which of the three agents is considered, the magnitude of the benefit in newly diagnosed cases (transplanted or non-transplanted) tends to be between 10 and 20 months per patient in terms of progression-free survival or survival; the survival benefit is smaller in relapsed or refractory disease. In addition, a single-institution observational analysis evaluated the outcomes in nearly 3000 consecutive patients examined between 1971 and 2006. The survival in patients diagnosed between 2001 and 2006 was longer than that observed in patients diagnosed between 1994 and 2000. This finding supports the conclusion that novel agents provide a survival improvement compared with traditional therapy. Formal cost-effectiveness studies on these three agents are still lacking. A MEDLINE search retrieved only four short papers or letters and no full-length analysis. Hence, the cost effectiveness of these agents needs further investigation, with separate assessments of the different therapeutic settings. In a simplified analysis, we tried to contrast the average cost of treatment for each of the novel agents versus their respective benefit, expressed in quality-adjusted survival. Despite its preliminary nature, our assessment indicates that the cost effectiveness of these three agents is likely to be within commonly accepted pharmacoeconomic thresholds.

Pomalidomide therapy for myeloma

INTRODUCTION

The Office of National Statistics (London, UK) has reported 4040 new patients in the year 2007, with an annual age standardized incidence rate of 4.8 per 100,000 population (range 4.7 - 5.0). Overall survival (OS) in the last decade has improved from 2 - 3 years to 7 - 8 years in the UK. The introduction of IMids for the treatment of myeloma has had a significant impact on outcomes in this life-threatening disease.

AREAS COVERED

Pomalidomide, a thalidomide analogue, is a promising anti-myeloma agent with encouraging responses in relapsed/refractory myeloma patients. Pomalidomide has a potent anti-myeloma activity in vitro and in vivo, acting both directly on myeloma cells and on the cells in the bone marrow microenvironment. We have reviewed the chemistry and mechanisms of action of pomalidomide and the literature on pre-clinical and early Phase I and II clinical trials that demonstrates significant clinical efficacy in the relapsed setting and in lenalidomide refractory myeloma patients.

EXPERT OPINION

Pomalidomide has shown significant activity in relapsed/refractory disease and is now being taken into Phase III trials in combination with dexamethasone. The exact place of pomalidomide in the management of myeloma, however, is evolving as more clinical experience is gained with this agent and further data published from clinical trials.

Nonproteasomal targets of the proteasome inhibitors bortezomib and carfilzomib: a link to clinical adverse events

PURPOSE

Bortezomib (Velcade), a dipeptide boronate 20S proteasome inhibitor and an approved treatment option for multiple myeloma, is associated with a treatment-emergent, painful peripheral neuropathy (PN) in more than 30% of patients. Carfilzomib, a tetrapeptide epoxyketone proteasome inhibitor, currently in clinical investigation in myeloma, is associated with low rates of PN. We sought to determine whether PN represents a target-mediated adverse drug reaction (ADR).

EXPERIMENTAL DESIGN

Neurodegenerative effects of proteasome inhibitors were assessed in an in vitro model utilizing a differentiated neuronal cell line. Secondary targets of both inhibitors were identified by a multifaceted approach involving candidate screening, profiling with an activity-based probe, and database mining. Secondary target activity was measured in rats and patients receiving both inhibitors.

RESULTS

Despite equivalent levels of proteasome inhibition, only bortezomib reduced neurite length, suggesting a nonproteasomal mechanism. In cell lysates, bortezomib, but not carfilzomib, significantly inhibited the serine proteases cathepsin G (CatG), cathepsin A, chymase, dipeptidyl peptidase II, and HtrA2/Omi at potencies near or equivalent to that for the proteasome. Inhibition of CatG was detected in splenocytes of rats receiving bortezomib and in peripheral blood mononuclear cells derived from bortezomib-treated patients. Levels of HtrA2/Omi, which is known to be involved in neuronal survival, were upregulated in neuronal cells exposed to both proteasome inhibitors but was inhibited only by bortezomib exposure.

CONCLUSION

These data show that bortezomib-induced neurodegeneration in vitro occurs via a proteasome-independent mechanism and that bortezomib inhibits several nonproteasomal targets in vitro and in vivo, which may play a role in its clinical ADR profile.

Phase II study of bortezomib and pegylated liposomal doxorubicin in the treatment of metastatic breast cancer

BACKGROUND

Based on preclinical studies and a phase I trial of the combination of bortezomib and pegylated liposomal doxorubicin (PLD), which both showed activity in breast cancer, we conducted a phase II study of this regimen in patients with metastatic breast cancer.

PATIENTS AND METHODS

Patients received bortezomib 1.3 mg/m2 on days 1, 4, 8, and 11 of an every-21-day cycle, along with PLD 30 mg/m2 on day 4. The primary objective was to evaluate the response rate of this combination, while secondary objectives were to obtain further safety data about this combination, to evaluate the time to disease progression (TTP), and to evaluate response by the breast cancer subtype.

RESULTS

One of 12 evaluable patients had a partial response (8%), while 3 (25%) had stable disease. At 26 months follow-up, the median overall survival was 4.3 months (95% CI, 1.2-26.2) and the median TTP was 1.3 months (95% CI, 0.8-14.0 months). The combination was well tolerated, with the most common events including low-grade nausea and vomiting, neutropenia, and neuropathy, and no cardiac toxicity was seen. Of the 7 tumors subtyped, no association was seen between intrinsic subtype or receptor status and response.

CONCLUSION

The combination of PLD and bortezomib was well tolerated but has minimal activity in heavily pretreated unselected metastatic breast cancer.

Pomalidomide therapy for multiple myeloma and myelofibrosis: an update

Thalidomide possesses potent anti-inflammatory, immunomodulatory, and antiangiogenic properties. Thalidomide combined with corticosteroids is therapeutically active in multiple myeloma and myelofibrosis (MF). Lenalidomide and pomalidomide are second-generation immunomodulatory drugs (IMiDs) that were created by chemical modification of thalidomide with the intent to reduce toxicity and enhance therapeutic activity. Both drugs have also been shown to be active in the treatment of myeloma and MF. Thalidomide is US Food and Drug Administration (FDA)-approved for use in acute erythema nodosum leprosum and, in combination with dexamethasone, in newly diagnosed myeloma. Lenalidomide is approved for use in low/intermediate-1 risk myelodysplastic syndromes associated with transfusion-dependent anemia and a deletion 5q cytogenetic abnormality and, in combination with dexamethasone, in relapsed myeloma. Pomalidomide is currently not FDA-approved. Herein, we summarize what is currently known about the biologic and therapeutic effects of pomalidomide.

Rapid early monoclonal protein reduction after therapy with bortezomib or bortezomib and pegylated liposomal doxorubicin in relapsed/refractory myeloma is associated with a longer time to progression

BACKGROUND

A rapid and early monoclonal (M) protein response during initial therapy in patients with multiple myeloma had been identified as a predictor of superior long-term outcome in some--but not all--studies.

METHODS

To determine if the parameter of M protein reduction was of value in the relapsed and/or refractory setting, retrospective landmark analyses were performed at the end of cycles 2 and 4 of a phase 3 study, which randomized such patients to receive bortezomib alone or pegylated liposomal doxorubicin (PLD) with bortezomib.

RESULTS

Compared with a <25% reduction in M protein at the landmark time point, patients with a 50% to <75% reduction after cycle 2 had a significantly lower hazard ratio (HR) for time to progression (HR = 0.41; 95% confidence interval [CI], 0.26-0.64; P <.001), as did those with a ≥75% reduction (HR = 0.26; 95% CI, 0.15-0.45; P < .001). In all of these groups, PLD + bortezomib provided superior outcomes to bortezomib alone, and did so without an increase in the risk of adverse events overall and with a predictable toxicity profile.

CONCLUSIONS

These analyses supported the possibility that a robust early M protein response is a good prognostic factor for long-term outcome of myeloma patients with relapsed and/or refractory disease receiving bortezomib or PLD + bortezomib.

Multiple myeloma: 2011 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Multiple myeloma is malignant plasma-cell disorder that accounts for ∼10% of all hematologic malignancies.

DIAGNOSIS

The diagnosis requires (1) 10% or more clonal plasma cells on bone marrow examination or a biopsy-proven plasmacytoma plus (2) evidence of end-organ damage felt to be related to the underlying plasma cell disorder.

RISK STRATIFICATION

Patients with 17p deletion, t(4;14), t(14;16), t(14;20), and karyotypic deletion 13 or hypodiploidy are considered to have high-risk myeloma. All others are considered to have standard-risk disease.

RISK-ADAPTED THERAPY

Standard-risk patients are treated with nonalkylator-based therapy such as lenalidomide plus low-dose dexamethasone (Rd) followed by autologous stem-cell transplantation (ASCT). If patients are tolerating the induction regimen treatment well, an alternative strategy is to continue initial therapy after stem-cell collection, reserving ASCT for first relapse. High-risk patients are treated with a bortezomib-based induction followed by ASCT and then bortezomib-based maintenance. Patients not eligible for ASCT can be treated with Rd for standard risk disease or a bortezomib-based regimen if high-risk features are present. To reduce toxicity, when using bortezomib, the once-weekly dose is preferred; similarly, when using dexamethasone, the low-dose approach (40 mg once a week) is preferred, unless there is a need for rapid disease control.

MANAGEMENT OF REFRACTORY DISEASE

Patients with indolent relapse can be treated first with lenalidomide, bortezomib, or alkylators plus low-dose corticosteroids. Patients with more aggressive relapse often require therapy with a combination of multiple active agents. The most promising new agents in development are pomalidomide and carfilizomib.

Therapy of relapsed and refractory multiple myeloma

Despite considerable improvements in first line treatment still the majority of patients experience relapse of multiple myeloma. Treatment decisions for relapse or refractory multiple myeloma should be based on a clinical decision path taking response and adverse events to previous therapy, myeloma specific complications and organ dysfunctions, overall clinical condition, age, cytogenetic information and prognostic factors into account. Bortezomib, thalidomide and lenalidomide have improved the therapeutic armentarium for patients with refractory or relapsed disease and are often used in combination with dexamethasone or chemotherapeutic agents. Combination therapies of novel agents in drug combination regimen are currently under investigation as well. For patients with a disease free survival of 12 month or longer after initial single or tandem high dose therapy and autologous stem cell transplantation (ASCT) repeat of high dose therapy with melphalan and ASCT should be considered in case of relapse. Radiotherapy and osteoplastic procedures can be used as adjunct to systemic therapy to treat local complications in particular vertebral pain caused by osteolytic bone disease. Cytogenetic tests, molecular techniques as gene expression profiling and other diagnostic will lead to a more individualized therapy. The integration of novel compounds into established regimen will be a major challenge for future clinical studies.

New insights into therapeutic targets in myeloma

Patient outcome in multiple myeloma (MM) has been remarkably improved due to the use of combination therapies including proteasome inhibitors and immunomodulatory drugs, which target the tumor in its BM microenvironment. Ongoing efforts to improve the treatment paradigm even further include using oncogenomics to better characterize molecular pathogenesis and to develop refined patient stratification and personalized medicine in MM; using models of MM in its BM milieu to identify novel targets and to validate next-generation therapeutics directed at these targets; developing immune-based therapies including mAbs, immunotoxins targeting MM cells and cytokines, and novel vaccine strategies; and using functional oncogenomics to inform the design of novel combination therapies. With continued rapid evolution of progress in these areas, MM will be a chronic illness with sustained complete response in a significant number of patients.

PR-924, a selective inhibitor of the immunoproteasome subunit LMP-7, blocks multiple myeloma cell growth both in vitro and in vivo

PR-924 is an LMP-7-selective tripeptide epoxyketone proteasome inhibitor that covalently modifies proteasomal N-terminal threonine active sites. In the present study, we show that PR-924 inhibits growth and triggers apoptosis in multiple myeloma (MM) cell lines and primary patient MM cells, without significantly affecting normal peripheral blood mononuclear cells. PR-924-induced apoptosis in MM cells is associated with activation of caspase-3, caspase-8, caspase-9, BID, PARP and cytochrome-c release. In vivo administration of PR-924 inhibits tumour growth in human plasmacytoma xenografts. Results from SCID-hu model show a significant reduction in the shIL-6R levels in mice treated with PR-924 versus vehicle-control. PR-924 treatment was well tolerated as evidenced by the lack of weight loss. Importantly, treatment of tumour-bearing mice with PR-924, but not vehicle alone, prolonged survival. Our preclinical findings therefore validate immunoproteasome LMP-7 subunit as a novel therapeutic target in MM.

Emerging therapies for the treatment of relapsed or refractory multiple myeloma

Encouraging progress has been made in the treatment of patients with relapsed/refractory multiple myeloma (MM). The rapidly evolving understanding of key pathways responsible for tumor growth and survival has led to the development of novel agents (including immunomodulatory drugs, proteasome inhibitors, histone deacetylase inhibitors, and other targeted agents) with the potential to provide significant improvements in response and survival, and influence treatment guidelines. This review summarizes recent advances in understanding of the biology of relapsed/refractory MM and clinical trials with novel targeted agents that are currently under investigation for patients with this disease.

Polymorphisms in the multiple drug resistance protein 1 and in P-glycoprotein 1 are associated with time to event outcomes in patients with advanced multiple myeloma treated with bortezomib and pegylated liposomal doxorubicin

Single nucleotide polymorphisms (SNPs) in the multiple drug resistance protein 1 (MRP1) and P-glycoprotein 1 (MDR1) genes modulate their ability to mediate drug resistance. We therefore sought to retrospectively evaluate their influence on outcomes in relapsed and/or refractory myeloma patients treated with bortezomib or bortezomib with pegylated liposomal doxorubicin (PLD). The MRP1/R723Q polymorphism was found in five subjects among the 279 patient study population, all of whom received PLD + bortezomib. Its presence was associated with a longer time to progression (TTP; median 330 vs. 129 days; p = 0.0008), progression-free survival (PFS; median 338 vs. 129 days; p = 0.0006), and overall survival (p = 0.0045). MDR1/3435(C > T), which was in Hardy-Weinberg equilibrium, showed a trend of association with PFS (p = 0.0578), response rate (p = 0.0782) and TTP (p = 0.0923) in PLD + bortezomib patients, though no correlation was found in the bortezomib arm. In a recessive genetic model, MDR1/3435 T was significantly associated with a better TTP (p = 0.0405) and PFS (p = 0.0186) in PLD + bortezomib patients. These findings suggest a potential role for MRP1 and MDR1 SNPs in modulating the long-term outcome of relapsed and/or refractory myeloma patients treated with PLD + bortezomib. Moreover, they support prospective studies to determine if such data could be used to tailor therapy to the genetic makeup of individual patients.

Bortezomib plus dexamethasone for relapsed or treatment refractory multiple myeloma: the collaborative study at six institutes in Kyoto and Osaka

We conducted a retrospective collaborative investigation of bortezomib (Bor) plus dexamethasone (Dex) therapy (BD Tx) for 88 relapsed or refractory (Rel/Ref) MM patients at six institutes. One cycle BD Tx comprised of Bor (1.3 mg/m²/day) on days 1, 4, 8 and 11, and Dex on days 1, 2, 4, 5, 8, 9, 11 and 12, every 21 days, and the mean number of BD Tx cycles was 3. The overall response rate was 66.9%, the median overall survival (OS) was 510 days, and the median progression-free survival (PFS) was 113 days. Attainment of partial response (PR) with the first course of BD Tx associated with the longer OS and PFS and late good responder, while no patient who did not achieve PR with the first cycle attained better than very good PR (VGPR) with the subsequent BD Tx. Patient age of less than 64 years old also associated with the longer OS and PFS. In addition, both an earlier disease stage and Dex dosage had a significant impact on OS, while the attainment of VGPR within 2 cycles had a significantly longer PFS. Earlier BD Tx courses may be predictive for the subsequent therapeutic pathway of Rel/Ref MM.

Cardiotoxicity of the anticancer therapeutic agent bortezomib

Recent case reports provided alarming signals that treatment with bortezomib might be associated with cardiac events. In all reported cases, patients experiencing cardiac problems were previously or concomitantly treated with other chemotherapeutics including cardiotoxic anthracyclines. Therefore, it is difficult to distinguish which components of the therapeutic regimens contribute to cardiotoxicity. Here, we addressed the influence of bortezomib on cardiac function in rats that were not treated with other drugs. Rats were treated with bortezomib at a dose of 0.2 mg/kg thrice weekly. Echocardiography, histopathology, and electron microscopy were used to evaluate cardiac function and structural changes. Respiration of the rat heart mitochondria was measured polarographically. Cell culture experiments were used to determine the influence of bortezomib on cardiomyocyte survival, contractility, Ca(2+) fluxes, induction of endoplasmic reticulum stress, and autophagy. Our findings indicate that bortezomib treatment leads to left ventricular contractile dysfunction manifested by a significant drop in left ventricle ejection fraction. Dramatic ultrastructural abnormalities of cardiomyocytes, especially within mitochondria, were accompanied by decreased ATP synthesis and decreased cardiomyocyte contractility. Monitoring of cardiac function in bortezomib-treated patients should be implemented to evaluate how frequently cardiotoxicity develops especially in patients with pre-existing cardiac conditions, as well as when using additional cardiotoxic drugs.

How I treat elderly patients with myeloma

The clinical approach to older patients with myeloma has to be modified to take into account comorbidities and the likelihood of higher treatment-related toxicity. Individualization of management and adequate supportive therapy are important to obtain the best response while minimizing adverse effects. Corticosteroids, novel agents, conventional cytotoxic agents, and high-dose chemotherapy with autotransplantation (modalities used in younger patients) are also used in older patients, although the elderly undergo transplantation less frequently. The sequential use of active agents singly and in different combinations has improved response rates and survival of all patients with myeloma, including the elderly.