Phase I-II trial of bortezomib plus oral cyclophosphamide and prednisone in relapsed and refractory multiple myeloma

Revisiting the Role of Alkylating Agents in Multiple Myeloma: Up-to-Date Evidence and Future Perspectives

From the 1960s to the early 2000s, alkylating agents (e.g., melphalan, cyclophosphamide, and bendamustine) remained a key component of standard therapy for newly-diagnosed or relapsed/refractory multiple myeloma (MM). Later on, their associated toxicities (including second primary malignancies) and the unprecedented efficacy of novel therapies have led clinicians to increasingly consider alkylator-free approaches. Meanwhile, new alkylating agents (e.g., melflufen) and new applications of old alkylators (e.g., lymphodepletion before chimeric antigen receptor T-cell [CAR-T] therapy) have emerged in recent years. Given the expanding use of antigen-directed modalities (e.g., monoclonal antibodies, bispecific antibodies, and CAR-T therapy), this review explores the current and future role of alkylating agents in different treatment settings (e.g., induction, consolidation, stem cell mobilization, pre-transplant conditioning, salvage, bridging, and lymphodepleting chemotherapy) to ellucidate the role of alkylator-based regimens in modern-day MM management.

Phase 2 study of oral thalidomide-cyclophosphamide-dexamethasone for recurrent/refractory adult Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a clonal histiocytic neoplasm with various clinical manifestations and heterogeneous prognoses. No standard therapy is available for recurrent/refractory LCH patients. This single-center, single-arm, phase 2 study enrolled 32 patients diagnosed with recurrent/refractory LCH. The TCD regimen (thalidomide 100 mg daily, cyclophosphamide 300 mg/m² Day 1, 8, 15, and dexamethasone 40 mg Day 1, 8, 15, 22 every 4 weeks) was administered for 12 cycles and thalidomide alone as maintenance for 12 months. The primary endpoint was event-free survival (EFS). Events were defined as progression during or after TCD therapy or death from any cause. After a median follow-up of 22 months (range 5-24 months), no patient died of all causes. The overall response rate was 87.5%, including 18 patients (56.3%) achieving complete remission and 10 patients (31.3%) as partial remission. The estimated 24-month EFS was 64.0%. Patients with risk organ involvement had similar EFS compared to patients without risk organ involvement (P = 0.38). The common toxicities of TCD regimen include grade 1-2 neutropenia (18.8%), grade 1-2 constipation (12.5%), grade 1-2 tiredness (9.4%) and grade 2 peripheral neuropathy (12.5%). Oral thalidomide, cyclophosphamide and dexamethasone are effective and safe regimen for recurrent/refractory LCH patients, particularly for patients with risk organ involvement.

Real-world outcomes with bortezomib-containing regimens and lenalidomide plus dexamethasone for the treatment of transplant-ineligible multiple myeloma: a multi-institutional report from the Canadian Myeloma Research Group database

Bortezomib-containing regimens (BCRs) represented standard, first-line therapy for transplant-ineligible multiple myeloma (TIMM) in Canada until the introduction of lenalidomide and low-dose dexamethasone (Ld). However, little comparative data exist to inform the selection of regimens. We assessed the outcomes for TIMM patients treated with cyclophosphamide, bortezomib and dexamethasone or prednisone (CyBorD/P), bortezomib, melphalan and prednisone (VMP), bortezomib and dexamethasone or prednisone (VD/P) and lenalidomide and low-dose dexamethasone (Ld) using the Canadian Myeloma Research Group database. Of 1156 TIMM patients evaluated, 82% received bortezomib combinations while 18% received Ld. Median progression-free survival (PFS) was 21·0, 21·1, 13·2 and 28·5 months (P = 0·0002) and median overall survival (OS) was 52·0, 63·6, 30·8 and 65·7 months (P < 0·0001) in the CyBorD/P, VMP, VD/P and Ld groups respectively. There was no significant difference in PFS and OS between the two triplet bortezomib regimens (VMP and CyBorD/P). Ld was associated with a longer PFS but not a significantly superior OS to date. Outcomes with the bortezomib-steroid doublet were inferior (VD/P). However, multivariable analysis identified features related to disease biology as the most important prognostic factors for PFS and OS. Such factors, as well as those affecting the physician's choice of regimen, are likely to influence the results observed with different regimens. This study demonstrated real-world outcomes in TIMM similar to those reported in clinical trials.

"Direct to Drug" screening as a precision medicine tool in multiple myeloma

Seventy-six FDA-approved oncology drugs and emerging therapeutics were evaluated in 25 multiple myeloma (MM) and 15 non-Hodgkin’s lymphoma cell lines and in 113 primary MM samples. Ex vivo drug sensitivities were mined for associations with clinical phenotype, cytogenetic, genetic mutation, and transcriptional profiles. In primary MM samples, proteasome inhibitors, dinaciclib, selinexor, venetoclax, auranofin, and histone deacetylating agents had the broadest cytotoxicity. Of interest, newly diagnosed patient samples were globally less sensitive especially to bromodomain inhibitors, inhibitors of receptor tyrosine kinases or non-receptor kinases, and DNA synthesis inhibitors. Clustering demonstrated six broad groupings of drug sensitivity linked with genomic biomarkers and clinical outcomes. For example, our findings mimic clinical observations of increased venetoclax responsiveness in t(11;14) patients but also identify an increased sensitivity profile in untreated patients, standard genetic risk, low plasma cell S-Phase, and in the absence of Gain(1q) and t(4;14). In contrast, increased ex vivo responsiveness to selinexor was associated with biomarkers of poor prognosis and later relapse patients. This “direct to drug” screening resource, paired with functional genomics, has the potential to successfully direct appropriate individualized therapeutic approaches in MM and to enrich clinical trials for likely responders.

Cyclophosphamide-bortezomib-dexamethasone compared with bortezomib-dexamethasone in transplantation-eligible patients with newly diagnosed multiple myeloma

Introduction

Cyclophosphamide-bortezomib-dexamethasone (CyBorD) is considered a standard induction regimen for transplant-eligible patients with newly diagnosed multiple myeloma (mm). It has not been prospectively compared with bortezomib-dexamethasone (Bor-Dex). We aimed to compare the efficacy of CyBorD and Bor-Dex induction in transplant-eligible patients.

Methods

In a retrospective observational study at a single tertiary centre, all patients with transplant-eligible mm who received induction with CyBorD or Bor-Dex between March 2008 and April 2016 were enrolled. Progression-free survival (pfs), response, and stem-cell collection for a first autologous stem-cell transplantation (ahsct) were compared.

Results

Of 155 patients enrolled, 78 (50.3%) had received CyBorD, and 77 (49.7%), Bor-Dex. The patients in the Bor-Dex cohort were younger than those in the CyBorD cohort (median: 57 years vs. 62 years; p = 0.0002) and more likely to have had treatment held, reduced, or discontinued (26% vs. 14.5%, p = 0.11). The stem-cell mobilization regimen for both cohorts was predominantly cyclophosphamide and granulocyte colony-stimulating factor (gcsf). Plerixafor was used more often for the CyBorD cohort (p = 0.009), and more collection failures occurred in the CyBorD cohort (p = 0.08). In patients receiving Bor-Dex, more cells were collected (9.9×10⁶ cells/kg vs. 7.7×10⁶cells/kg, p = 0.007). At day +100, a very good partial response or better was achieved in 75% of the CyBorD cohort and in 73% of the Bor-Dex cohort (p = 0.77). Median pfs was 3.2 years in the Bor-Dex cohort and 3.7 years in the CyBorD cohort (p = 0.56).

Conclusions

Overall efficacy was similar in our patients receiving CyBorD and Bor-Dex. After ahsct, no difference in depth of response or pfs was observed. Cyclophosphamide-gcsf seems to increase collection failures and hospitalizations in patients receiving CyBorD. Prospective studies are required to examine that relationship.

Synergistic Apoptotic Effects of Bortezomib and Methylstat on Multiple Myeloma Cells

BACKGROUND

In this study, we aimed to determine synergistic apoptotic and cytotoxic effects of methylstat and bortezomib on U266 and ARH77 multiple myeloma (MM) cells.

METHODS

Cytotoxic effects of the drugs were demonstrated by MTT cell proliferation assay while apoptotic effects were examined by loss of mitochondrial membrane potential (MMP) by JC-1 MMP detection kit, changes in caspase-3 enzyme activity and Annexin-V apoptosis assay by flow cytometry. Expression levels of apoptotic and antiapoptotic genes were examined by qRT-PCR.

RESULTS

Our results showed that combination of methylstat and bortezomib have synergistic antiproliferative effect on MM cells as compared to either agent alone. These results were also confirmed by showing synergistic apoptotic effects determined by increased loss of mitochondrial membrane potential and increased caspase-3 enzyme activity and relocation of phosphotidyleserine on the cell membrane by Annexin-V/PI double staining. Combination of bortezomib with methylstat arrested cells at the S phase of the cell cycle. Methylstat treatment caused upregulation of FASLG, NGFR, TNF, TNFRS10B and TNFRS1B apoptotic genes and downregulation of AKT1, AVEN, BAG1 BCL2L2 and RELA antiapoptotic genes in a dose and time dependent manner.

CONCLUSION

In conclusion, our data suggested that bortezomib in combination with methylstat decreased cell proliferation and induced apoptosis significantly in U266 and ARH77 cells. When supported with in vivo analyses, methylstat might be considered as a potential new agent for the treatment of MM.

A look at treatment strategies for relapsed multiple myeloma

INTRODUCTION

Multiple myeloma treatment considerably improved during the past decade, thanks to novel effective drugs, a better understanding of myeloma biology and clonal heterogeneity, and an improved management of toxicities. The choice of regimen at relapse is usually based on prior response, toxicities, age and comorbidities of relapsed patients. Areas covered: A review was performed of the most recent and effective therapeutic strategies for the relapsed myeloma setting, by documenting the latest clinical evidence from phase II and III clinical trials. Of note, new drugs, such as carfilzomib, ixazomib, pomalidomide, daratumumab and elotuzumab, alone or in combinations in doublet or triplet regimens, have greatly increased the treatment armamentarium against myeloma. Expert commentary: Impressive results have been obtained with new drugs in relapsed patients. Besides number of prior therapies and previous response, other factors play a crucial role in the selection of therapy. Re-challenge with previous drugs can be adopted if previous responses lasted at least 6 months and therapy had induced low toxicity. Patients' risk status can further help to appropriately select therapy at relapse, and clinical trials will allow physicians to use newer targeted therapies and immune-therapies, thus delaying palliative approaches to later relapse stages.

Cyclophosphamide's addition in relapsed/refractory multiple myeloma patients with biochemical progression during lenalidomide-dexamethasone treatment

OBJECTIVE

The aim of this study was to evaluate the addition of cyclophosphamide in relapsed-refractory multiple myeloma patients (RRMM) who experienced biochemical relapse or progression without CRAB, during treatment with lenalidomide and dexamethasone (Rd), to slow down the progression in active relapse.

METHODS

This analysis included 31 patients with RRMM treated with Rd who received cyclophosphamide (CRd) at biochemical relapse. The CRd regimen was continued until disease progression.

RESULTS

The median number of CRd cycles administered was 8 (range: 1-35). A response was observed in 9 (29%) patients. After a median observation time of 11 months, the median overall survival (OS) from the beginning of CRd was 17.7 months. The median progression-free survival (PFS) from the beginning of CRd was 13.1 months.

CONCLUSION

The addition of cyclophosphamide delays the progression in patients who present a biochemical relapse during Rd treatment. The response rate and the duration of PFS obtained with minimal toxicities and low costs induced us to setting up a randomized clinical trial.

Use of carfilzomib in second-line therapy and beyond for relapsed multiple myeloma

The development of proteasome inhibitors has been a major advance in therapy of multiple myeloma, accounting, in part, for the significant increase in the survival of patients diagnosed with this disease. Bortezomib was the first proteasome inhibitor to be approved for the therapy of multiple myeloma. Carfilzomib is a second-generation proteasome inhibitor with irreversible binding to proteasome and less off-target toxicity. The drug has been approved for use in relapsed/refractory multiple myeloma. In this article, we review the use of carfilzomib as second-line therapy in multiple myeloma. We also review the current standards of care for relapsed/refractory multiple myeloma, with particular focus on the use of carfilzomib in advanced disease.

Current and developing synthetic pharmacotherapy for treating relapsed/refractory multiple myeloma

INTRODUCTION

The introduction of novel agents has significantly improved multiple myeloma (MM) patient outcome during the last two decades. MM received the most drug approvals for any one malignancy during this time period, both in the United States as well as in Europe. Areas covered: Proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies are prototype drug classes, which target both specific MM cell functions, as well as the tumor supportive bone marrow microenvironment, and represent current cornerstones of MM therapy. Importantly, the unprecedented extent and frequency of durable responses, in relapsed/refractory multiple myeloma (RRMM), in particular, is predominantly based on the combinatorial use of these agents with conventional chemotherapeutics or representatives of other drug classes. This article will summarize past landmark discoveries in MM that led to the dramatic progress of today's clinical practice. Moreover, developing strategies will be discussed that are likely to yet improve patient outcome even further. Expert opinion: Despite significant therapeutic advancements, MM remains an incurable disease. With several novel agents in the preclinical and early clinical pipeline, among those novel CD38 and BCMA mAbs, immune checkpoint inhibitors, as well as ricolinostat, selinexor, venetoclax, CAR-T cells, and vaccines, further advances in MM patient outcome are expected in the near future.

P-Glycoprotein Inhibition Sensitizes Human Breast Cancer Cells to Proteasome Inhibitors

Although effective for the treatment of hematological malignancies, the FDA approved proteasome inhibitors bortezomib and carfilzomib have limited efficacy in solid tumors including triple negative breast cancer (TNBC). Chemotherapy is the only option for treating TNBC due to the absence of specific therapeutic targets. Therefore, development of new TNBC therapeutic strategies has been warranted. We studied whether P-glycoprotein (P-gp) inhibition could sensitize TNBC cells to proteasome inhibitors. When verapamil, a P-gp inhibitor, was combined with the proteasome inhibitor MG132, bortezomib, or carfilzomib, the cytotoxic effects and apoptosis in TNBC MDA-MB-231 cells were enhanced, compared to each treatment alone. Furthermore, addition of verapamil improved proteasome-inhibitory properties of MG132, bortezomib, or carfilzomib in MDA-MB-231 cells, as shown by the increased accumulation of ubiquitinated proteins and proteasome substrates such as IκBα and p27^kip1 . Additionally, when nicardipine, another P-gp inhibitor, was combined with bortezomib or carfilzomib, enhanced inhibition of MDA-MB-231 cell proliferation was observed. These findings indicate that P-gp inhibitors could sensitize TNBC cells to structurally and functionally diverse proteasome inhibitors and might provide new treatment strategy for TNBC. J. Cell. Biochem. 118: 1239-1248, 2017. © 2016 Wiley Periodicals, Inc.

Multiple myeloma treatment at relapse after autologous stem cell transplantation: A practical analysis

Over the past decade, significant advances have been made in the field of multiple myeloma. Introduction of the so-called novel agents, proteasome inhibitors (PI) and immunomodulatory drugs (IMiD), and improved supportive care have resulted in significantly better outcome. Standard first line treatment in fit patients include PI and IMiD based induction, high dose melphalan with autologous hematopoietic stem cell transplantation (ASCT) and consolidation/maintenance. However, despite these progresses MM remains incurable for the majority of patients and most patients will relapse. Next generation PI (carfilzomib, ixazomib) and IMiD (pomalidomide) and new therapeutic classes: monoclonal antibody (elotuzumab, daratumumab) and pan-deacetylase inhibitors (panobinostat) have been successfully evaluated in relapse multiple myeloma. Some of these new agents are now approved for multiple myeloma treatment at relapse. However choosing the most appropriate treatment at relapse may be difficult. This review sum up the most important studies and provide evidence to choose the most relevant therapeutic strategy for relapse after ASCT, based on disease, patient and previous treatment related parameters.

The MUK five protocol: a phase II randomised, controlled, parallel group, multi-centre trial of carfilzomib, cyclophosphamide and dexamethasone (CCD) vs. cyclophosphamide, bortezomib (Velcade) and dexamethasone (CVD) for first relapse and primary refractory multiple myeloma

Background

Multiple myeloma is a plasma cell tumour with an annual incidence in the UK of approximately 40–50 per million i.e. about 4500 new cases per annum. The triple combination cyclophosphamide, bortezomib (Velcade®) and dexamethasone (CVD) is an effective regimen at relapse and has emerged in recent years as the standard therapy at first relapse in the UK. Carfilzomib has good activity as a single agent in the relapsed setting, and it is expected that efficacy will be improved when used in combination with dexamethasone and cyclophosphamide.

Methods

MUK Five is a phase II open label, randomised, controlled, parallel group, multi-centre trial that will compare the activity of carfilzomib, cyclophosphamide and dexamethasone (CCD) with that of CVD, given over an equivalent treatment period (24 weeks), in participants with multiple myeloma at first relapse, or refractory to no more than 1 line of treatment. In addition, the study also aims to assess the utility of a maintenance schedule of carfilzomib in these participants. The primary objective of the trial is to assess whether CCD provides non-inferior activity in terms of ≥ VGPR rates at 24 weeks, and whether the addition of maintenance treatment with carfilzomib to CCD provides superior activity in terms of progression-free survival, as compared to CCD with no maintenance. Secondary objectives include comparing toxicity profiles, further summarizing and comparing the activity of the different treatment arms and analysis of the effect of each treatment arm on minimal residual disease status.

Discussion

The development of carfilzomib offers the opportunity to further explore the anti-tumour efficacy of proteasome inhibition and, based on the available evidence, it is important and timely to obtain data on the activity, toxicity and tolerability of this drug. In contrast to ongoing phase III trials, this phase II trial has a unique subset of participants diagnosed with multiple myeloma at first relapse or refractory to no more than 1 line of treatment and will also evaluate the utility of maintenance with carfilzomib for up to 18 months and investigate minimal residual disease status to provide information on depth of response and the prognostic impact thereof.

Trial registration

The trial is registered under ISRCTN17354232, December 2012.

Cyclophosphamide and Bortezomib With Prednisone or Dexamethasone for the Treatment of Relapsed and Refractory Multiple Myeloma

INTRODUCTION

Cyclophosphamide, bortezomib, and prednisone (CyBorP) is a highly effective, well-tolerated regimen in relapsed/refractory multiple myeloma. CyBorP, originally developed at our center to include weekly bortezomib (Bor) and alternate-day prednisone (P), was recently modified so that weekly dexamethasone (D) replaced prednisone.

PATIENTS AND METHODS

To assess the effectiveness and tolerability of CyBorP/D in real-world practice, we identified 96 relapsed/refractory patients who received ≥ 1 28-day cycle of CyBorP/D, consisting of cyclophosphamide 300 mg/m(2) (days 1, 8, 15, and 22), Bor 1.0 to 1.5 mg/m(2) (days 1, 8, and 15), and either P 50 to 100 mg on alternate days or D 20 to 40 mg weekly between 2007 and 2013.

RESULTS

Sixty-six (69%) patients achieved ≥ partial response: 16 with clinical complete response and 25 with very good partial response; 22 others had stable disease. Progression-free and overall survival for all patients were 16.2 months (95% confidence interval [CI], 7.7-20.1 months) and 26.3 months (95% CI, 21.6-81.2 months), respectively. Although 26 patients had prior Bor exposure, there was no difference in progression-free or overall survival versus Bor-naive patients.

CONCLUSION

Toxicities with CyBorP/D were generally mild and manageable. New onset peripheral neuropathy was seen in 13 cases; 9 of 26 patients with pre-existing peripheral neuropathy developed worsening symptoms. No second primary malignancies were observed.

American Society of Blood and Marrow Transplantation, European Society of Blood and Marrow Transplantation, Blood and Marrow Transplant Clinical Trials Network, and International Myeloma Working Group Consensus Conference on Salvage Hematopoietic Cell Transplantation in Patients with Relapsed Multiple Myeloma

In contrast to the upfront setting in which the role of high-dose therapy with autologous hematopoietic cell transplantation (HCT) as consolidation of a first remission in patients with multiple myeloma (MM) is well established, the role of high-dose therapy with autologous or allogeneic HCT has not been extensively studied in MM patients relapsing after primary therapy. The International Myeloma Working Group together with the Blood and Marrow Transplant Clinical Trials Network, the American Society of Blood and Marrow Transplantation, and the European Society of Blood and Marrow Transplantation convened a meeting of MM experts to: (1) summarize current knowledge regarding the role of autologous or allogeneic HCT in MM patients progressing after primary therapy, (2) propose guidelines for the use of salvage HCT in MM, (3) identify knowledge gaps, (4) propose a research agenda, and (5) develop a collaborative initiative to move the research agenda forward. After reviewing the available data, the expert committee came to the following consensus statement for salvage autologous HCT: (1) In transplantation-eligible patients relapsing after primary therapy that did NOT include an autologous HCT, high-dose therapy with HCT as part of salvage therapy should be considered standard; (2) High-dose therapy and autologous HCT should be considered appropriate therapy for any patients relapsing after primary therapy that includes an autologous HCT with initial remission duration of more than 18 months; (3) High-dose therapy and autologous HCT can be used as a bridging strategy to allogeneic HCT; (4) The role of postsalvage HCT maintenance needs to be explored in the context of well-designed prospective trials that should include new agents, such as monoclonal antibodies, immune-modulating agents, and oral proteasome inhibitors; (5) Autologous HCT consolidation should be explored as a strategy to develop novel conditioning regimens or post-HCT strategies in patients with short (less than 18 months remissions) after primary therapy; and (6) Prospective randomized trials need to be performed to define the role of salvage autologous HCT in patients with MM relapsing after primary therapy comparing it to "best non-HCT" therapy. The expert committee also underscored the importance of collecting enough hematopoietic stem cells to perform 2 transplantations early in the course of the disease. Regarding allogeneic HCT, the expert committee agreed on the following consensus statements: (1) Allogeneic HCT should be considered appropriate therapy for any eligible patient with early relapse (less than 24 months) after primary therapy that included an autologous HCT and/or high-risk features (ie, cytogenetics, extramedullary disease, plasma cell leukemia, or high lactate dehydrogenase); (2) Allogeneic HCT should be performed in the context of a clinical trial if possible; (3) The role of postallogeneic HCT maintenance therapy needs to be explored in the context of well-designed prospective trials; and (4) Prospective randomized trials need to be performed to define the role salvage allogeneic HCT in patients with MM relapsing after primary therapy.

Phase I dose-escalation study of cyclophosphamide combined with bortezomib and dexamethasone in Japanese patients with relapsed and/or refractory multiple myeloma

The present study was conducted to determine the recommended dose (RD) of cyclophosphamide (CPM) in the CBD regimen, a triplet combination of CPM, bortezomib (BTZ), and dexamethasone (Dex), for relapsed and/or refractory multiple myeloma (RRMM). Patients received intravenous CPM on days 1 and 8 at one of three dose levels: 300, 400, or 500 mg/m(2), with dose escalation in a 3 + 3 design. BTZ at 1.3 mg/m(2) was given twice weekly in 3-week cycles, with Dex at 20 mg/m(2) on the day of and day after BTZ. Of 16 patients enrolled, 15 eligible patients were allocated to the study. Dose-limiting toxicities (DLTs) were seen in two patients: one in dose level 1 with increased γ-GTP and the other in dose level 3 with increased γ-GTP and ALT. Both patients spontaneously recovered from DLT. Neither therapy-related mortality nor severe adverse events were reported during the study. Therefore, the RD of CPM was determined as 500 mg/m(2). Overall, 2 (13.3 %), 1 (6.7 %), and 8 (53.3 %) patients achieved CR, VGPR, and PR, respectively. The regimen was well tolerated and showed promising activity in patients with RRMM.

The ubiquitin-proteasome system: opportunities for therapeutic intervention in solid tumors

The destruction of proteins via the ubiquitin-proteasome system is a multi-step, complex process involving polyubiquitination of substrate proteins, followed by proteolytic degradation by the macromolecular 26S proteasome complex. Inhibitors of the proteasome promote the accumulation of proteins that are deleterious to cell survival, and represent promising anti-cancer agents. In multiple myeloma and mantle cell lymphoma, treatment with the first-generation proteasome inhibitor, bortezomib, or the second-generation inhibitor, carfilzomib, has demonstrated significant therapeutic benefit in humans. This has prompted United States Food and Drug Administration (US FDA) approval of these agents and development of additional second-generation compounds with improved properties. There is considerable interest in extending the benefits of proteasome inhibitors to the treatment of solid tumor malignancies. Herein, we review progress that has been made in the preclinical development and clinical evaluation of different proteasome inhibitors in solid tumors. In addition, we describe several novel approaches that are currently being pursued for the treatment of solid tumors, including drug combinatorial strategies incorporating proteasome inhibitors and the targeting of components of the ubiquitin-proteasome system that are distinct from the 26S proteasome complex.

A practical approach to relapsed multiple myeloma

There has been tremendous progress made in multiple myeloma in the last decade, resulting in improved overall survival for all patients, including those with high-risk disease and those ineligible for transplantation. However, despite the addition of several novel agents, unprecedented response rates, and our ability to achieve complete remission in the majority of patients, the disease remains incurable in nearly all and will require repeated therapies. With many options available to the clinician, there is no simple or ideal sequence of treatments that has been established, so the choice of relapsed therapy is based on a series of factors that include response and tolerability of prior therapies, risk status, available novel agents, aggressiveness of relapse, renal function, performance status, cost, etc. This chapter provides practical guidance in selecting relapsed therapies structured through a series of 5 questions that can inform the decision. Specific emphasis is placed on the 2 most recent novel agents, carfilzomib and pomalidomide, but agents in development are also included.

Phase I-II trial of oral cyclophosphamide, prednisone and lenalidomide for the treatment of patients with relapsed and refractory multiple myeloma

This single institution, open label Phase I-II dose escalation trial evaluated the safety and efficacy of the combination of lenalidomide (Revlimid®), cyclophosphamide and prednisone (CPR) in patients with relapsed/refractory multiple myeloma. The maximal administered dose of CPR consisted of cyclophosphamide 300 mg/m(2) on day 1, 8, and 15, lenalidomide 25 mg on d 1-21 and prednisone 100 mg every other day in a 28-d cycle. Between November 2007 and June 2009, 32 patients were entered in cohorts of three at three dose levels. The median age was 64 years, 59% were male, with a median two prior regimens. Responding patients could stay on treatment until progression. The full-dose CPR regimen produced no dose-limiting toxicity and was delivered for a median of 16 months (3·5-65 months) with acceptable safety and tolerance. The overall response rate (≥ partial response) was 94% at a median follow up of 28 months. The median progression-free survival was 16·1 months [95% confidence interval (CI); 10·9-22·5 months], while the median overall survival was 27·6 months (95% CI; 16·8-36·6 months). Only the beta-2 microglobulin level at protocol entry correlated with a better survival (P = 0·047). These observations compare favourably with other 2- and 3- drug combinations for relapsed/refractory myeloma, and suggest that CPR should be evaluated further in the setting of relapsed/refractory disease, or in newly diagnosed patients.

Novel agents and new therapeutic approaches for treatment of multiple myeloma

This review summarizes the therapeutic strategies and the drugs actually in development for the management of myeloma patients. Multiple myeloma is caused by the expansion of monoclonal plasma cells and secretion of M-protein (immunoglobulins, Bence Jones protein and free light chains). Multiple myeloma still remains an incurable disease with a high incidence rate in the elderly, despite the introduction of several new therapeutic agents (bortezomib, lenalidomide and thalidomide) which have changed its natural history. The high heterogeneity of this disease leads to large differences in clinical responses to treatments. Thus, the choice of the best treatment is a difficult issue. However, the introduction of new drugs has made it possible to achieve high response rates and good quality responses with long-term disease control. Interactions between tumor cells and their bone marrow microenvironment play a pivotal role in the development, maintenance, and progression of myeloma, inducing also drug resistance. These knowledges have improved treatment options, leading to the approval of new drugs which not only target the malignant cell itself, but also its microenvironment. These agents are in preclinical/early clinical evaluation and they appear to further improve disease control, but their use is still not approved outside of clinical trials.

Salvage therapy with pegylated liposomal doxorubicin, bortezomib, cyclophosphamide, and dexamethasone in relapsed/refractory myeloma patients

OBJECTIVES

In vitro studies have shown synergistic anti-myeloma effects of bortezomib combined with alkylating agents or anthracycline. We tested safety and efficacy of the combination of bortezomib, doxorubicin cyclophosphamide, and dexamethasone (ABCD) in the treatment of relapsed/refractory myeloma.

METHODS

ABCD consisted of bortezomib given intravenous (IV) at dosage 1.3 mg/m(2) , dexamethasone 40 mg IV on days 1, 4, 8, and 15, pegylated liposomal doxorubicin (PLD) 20 mg IV on days 1 and 15, plus cyclophosphamide 100 mg/d per os for 15 d. Between January 2008 and February 2009, 24 patients received a median of four 28-d ABCD cycles (range 1-6). All patients had been already treated with a median of two previous lines of treatment (range 1-6): 38% were resistant to previous therapies and 62% were relapsed.

RESULTS

Clinical response was observed in 12 patients (50%), including 29% of very good partial remissions or better. Side effects included hematological toxicity (31% any grade), grades 3-4 thrombocytopenia (9%), grades 3-4 anemia (17%). Non-hematological toxicity affected 32% of administered cycles and included gastrointestinal disturbances (54%), peripheral neuropathy (8%), and infections (8%). After a median follow-up of 21.5 months (range 2-44 months), median of progression-free survival (PFS) was 8.7 months and median overall survival was 22.5 months. Achieving at least partial response within the second cycle was associated with a better PFS (19.5 months vs. 3.5 months), P = 0.03, HR 0.35 (CI 95% 0.13-0.90).

CONCLUSION

ABCD is safe and effective for relapsed/refractory MM subjects previously treated with novel agents.

Current strategies for treatment of relapsed/refractory multiple myeloma

In spite of significant advances in the management of multiple myeloma (MM), the disease remains incurable and nearly all patients ultimately relapse and require salvage chemotherapy. As such, relapsed and relapsed-refractory MM remains a critical area of research pertaining to biological mechanisms of progression and chemotherapy resistance, as well as to the development of new pharmacologic agents and immunologic approaches for the disease. The immunomodulatory agents and proteasome inhibitors represent the cornerstone of treatment in this setting, with combination regimens incorporating these drugs demonstrating encouraging rates and duration of response, including the newer agents, pomalidomide and carfilzomib. In addition, novel drug classes have shown promising activity in RR MM, including the orally-administered proteasome inhibitors ixazomib and oprozomib; monoclonal antibodies such as the anti-CS1 monoclonal antibody elotuzumab and anti-CD38 monoclonal antibody daratumumab; and histone deacetylase inhibitors such as panobinostat and rocilinostat.

Bortezomib combination therapy in multiple myeloma

Bortezomib was approved for the treatment of multiple myeloma (MM) in 2003. Since then several bortezomib-based combination therapies have emerged. Although some combinations have been preceded by preclinical investigations, most have followed the inevitable process in which active (or potentially active) drugs are combined with each other to create new treatment regimens. Regimens that have combined bortezomib with corticosteroids, alkylating agents, thalidomide, and/or lenalidomide have resulted in high response rates. Despite the higher and often deeper response rates and prolongation of progression-free survival with bortezomib-based multiagent regimens, an overall survival (OS) advantage has not been demonstrated with most combinations compared to the sequential approach of using anti-myeloma agents, particularly in patients less than 65 years of age with newly diagnosed myeloma. The unique properties of some of these regimens can be taken into account when choosing a particular regimen based on the clinical scenario. For example, the combination of bortezomib, thalidomide, and dexamethasone (VTD) has particular value in renal failure since none of the drugs need dose modification. Similarly, the combination chemotherapy regimen VDT-PACE (bortezomib, dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, and etoposide) is of particular value in patients presenting with aggressive disease such as extramedullary plasmacytomas or plasma cell leukemia. Ongoing clinical trials are testing combinations of bortezomib with several other classes of agents, including monoclonal antibodies, and inhibitors of deacetylases, heat shock proteins, phosphatidyl inositol 3-kinase/Akt/mammalian target of rapamycin pathway and farnesyl transferase.

Successful use of cyclophosphamide as an add-on therapy for multiple myeloma patients with acquired resistance to bortezomib or lenalidomide

Novel agents such as thalidomide, lenalidomide, and bortezomib have been shown to possess potent activity against multiple myeloma. However, the treatment strategy for patients who acquired resistance to these agents has not been established. In addition to switching drug classes, intensified treatment strategy, including increase in the dosage of current agents and addition of other agents, may be considered for these patients. We here describe 2 myeloma patients with acquired resistance to bortezomib or lenalidomide, in whom add-on therapy with low-dose cyclophosphamide was effective and tolerable. These cases suggest that add-on therapy with cyclophosphamide is one of the treatment options to overcome resistance to novel agents in patients with multiple myeloma. A larger prospective study is needed to clarify the efficacy and safety of this strategy for novel agent-resistant multiple myeloma.

Weekly intravenous bortezomib is effective and well tolerated in relapsed/refractory myeloma

OBJECTIVES

Bortezomib is an effective antimyeloma therapy, but clinical benefits can be limited by neurotoxicity. In newly diagnosed, older patients, modification of the biweekly dosing schedule to weekly regimens improves tolerability whilst maintaining efficacy. There is less information on the efficacy and tolerability of weekly bortezomib regimens in the relapsed/refractory setting. Here, we report our experience of weekly intravenous bortezomib in clinical practice in relapsed/refractory patients.

METHODS

We analysed fifty-two patients who received weekly bortezomib for relapsed/refractory MM.

RESULTS

Thirty-one per cent of patients received bortezomib beyond first relapse. Almost all (94%) also received steroids and 48% also received an alkylator. The median cumulative dose was 22.6 mg/m(2) , and median length of treatment was 164 d. Three patients reported grade 2 sensory neuropathy, and one reported grade 3 motor neuropathy. There were no grade 4 neurotoxicities. Eighty-three per cent achieved a PR or greater, and the median PFS for the whole group was 13 months. One-year PFS and OS were 53% (95% CI 39-66.6%) and 78% (95% CI 66.7-89.6%), respectively.

CONCLUSIONS

Weekly intravenous bortezomib when used in combination with steroids ± alkylator is effective in relapsed/refractory MM, producing outcomes comparable with biweekly regimens and with lower rates of peripheral neuropathy.

Good clinical activity and favorable toxicity profile of once weekly bortezomib, fotemustine, and dexamethasone (B-MuD) for the treatment of relapsed multiple myeloma

Since multiple myeloma (MM) is still not-curable, the management of relapse remains challenging. Given the known efficacy of alkylating agents in MM, we conducted a phase I/II study to test a new three drug combination in which Fotemustine (Muphoran), an alkylating agent of nitrosurea family, was added to bortezomib + dexamethasone backbone (B-MuD) for the treatment of MM relapsed patients. Fotemustine was administered at two dose levels (80–100 mg/m² i.v.) on day 1. The original 21-day schedule was early amended for extra-hematological toxicity and a 35-day schedule was adopted (Bortezomib 1.3 mg/m² i.v. on days 1, 8, 15, and 22, Dexamethasone 20 mg i.v. on days 1, 8, 15, and 22) for a total of six courses. Twenty-four patients were enrolled. The maximum tolerated dose of Fotemustine was 100 mg/m². The overall response rate was of 62% (CR 8%, VGPR 33%, and PR 21%). The median OS was 28.5 months, the median progression-free survival (PFS) was 19.1 months. B-MuD resulted effective in patients previous exposed to bortezomib without difference of response (P = 0.25) and PFS (P = 0.87) when compared to bortezomib-naive patients. Thrombocytopenia was the most common AE overall. In conclusion, B-MuD is an effective and well tolerated combination in relapsed MM patients even in advanced disease phase. © Am. J. Hematol., 88:102–106, 2013. © 2012 Wiley Periodicals, Inc.

Bortezomib-cyclophosphamide-dexamethasone for relapsing multiple myeloma

OBJECTIVES

In vitro studies have shown synergistic antimyeloma effects with the combination of bortezomib and alkylating agents. Combinations of bortezomib, cyclophosphamide, and dexamethasone are rational with the prospect of superior antitumor activity with independent toxicity.

METHODS

Between December 2004 and April 2007, we treated 44 patients with relapsing multiple myeloma with the combination of bortezomib 1.3 mg/m intravenously on days 1, 4, 8, 11; dexamethasone 20 mg/m orally daily for 4 days beginning on days 1, 9 and 17; and cyclophosphamide 70 mg/m orally twice daily for 4 days. A second course was given 1 month later.

RESULTS

Clinical response was observed in 32 patients (73%) including 26 with disease in partial remission (59%), and 6 with disease in complete remission (14%). Side effects were uncommon and mild, except for grade 3 thrombocytopenia in 15%, infection in 5% and constipation in 2% of patients. The median remission time of responding patients was 10 months that contributed to significantly longer median survival for patients with responsive disease (33 mo) than for those with unresponsive disease (12 mo) (P < 0.01).

CONCLUSION

Bortezomib-cyclophosphamide-dexamethasone was an effective, well-tolerated combination for the treatment of relapsing multiple myeloma.

High frequencies of response after limited primary therapy for multiple myeloma

In an effort to maintain high primary response rates against multiple myeloma and without serious toxicity, we assessed 3 different bortezomib combinations in small numbers of patients, with combinations that included cyclophosphamide and lenalidomide in modest doses and for short courses. Remissions occurred in approximately 90% of patients, with rare episodes of serious drug-related adverse effects.

BACKGROUND

Recent bortezomib combinations have induced remission in approximately 90% of patients newly diagnosed, with moderate frequency of adverse effects.

PATIENTS

In an attempt to reduce adverse effects, and to prepare qualified patients for early intensification, we assessed the antimyeloma effect and toxicity of 3 different bortezomib combinations in small numbers of patients.

METHODS

With reduced doses and short durations of exposure, we combined bortezomib with (a) cyclophosphamide/dexamethasone, (b) lenalidomide/dexamethasone/liposomal doxorubicin, and (c) cyclophosphamide/dexamethasone/lenalidomide.

RESULTS

Response rates were high, with rare episodes of severe drug-related toxicity.

CONCLUSIONS

Further study of similar combinations of effective drugs given in limited doses and for short durations would be useful.

Management strategies for relapsed/refractory multiple myeloma: current clinical perspectives

In the last decade, the introduction of novel agents including the immunomodulatory drugs thalidomide and lenalidomide, and the first-in-class proteasome inhibitor bortezomib, has dramatically improved clinical outcome in patients with relapsed/refractory multiple myeloma (MM) compared to conventional chemotherapy alone. Although combination treatment approaches with traditional cytotoxic agents and novel agents have led to response rates as high as 85% in patients with relapsed/refractory disease, not all patients will respond to established novel agents, and even those who do respond will ultimately relapse or become refractory to currently available regimens. There is no generally accepted standard treatment for patients with relapsed/refractory disease; however, both disease-related (eg, quality and duration of response to previous therapies and the aggressiveness of the relapse) and patient-related (eg, preexisting toxicities, comorbid conditions, quality of life, age, and performance status) factors should be considered when selecting the best treatment option. This article will review up-to-date approaches for managing patients with relapsed/refractory MM, including the efficacy and safety of established novel agents, the use of adjunctive/supportive care, and strategies for tailored treatment.

A comparison of bortezomib, cyclophosphamide, and dexamethasone (Vel-CD) chemotherapy without and with thalidomide (Vel-CTD) for the treatment of relapsed or refractory multiple myeloma

We compared the clinical responses and toxicities between bortezomib-based salvage chemotherapy combined with cyclophosphamide, thalidomide, and dexamethasone(Vel-CTD) and without thalidomide (Vel-CD) in patients with relapsed or refractory MM. Eighty-six patients received at least two cycles of treatment with Vel-CTD (bortezomib 1.3 mg/m2 i.v. on days 1, 4, 8, and 11; cyclophosphamide 150 mg/m2 orally on days 1–4; thalidomide 50–100 mg/day orally every day; and dexamethasone 20 mg/m2 i.v. on days 1, 4, 8, and 11 every 3 weeks), and 67 patients were given at least two cycles of Vel-CD, which is the same regimen as Vel-CTD except without thalidomide. The overall response rates of the Vel-CD and Vel-CTD groups were 88% and 90% (p>0.05), respectively. There was no difference in the progression free survival (p = 0.69) and overall survival rates(p = 0.49) between the two groups. Grade 3 or more adverse hematologic events occurred in the same proportion of patients in both groups. In terms of non-hematologic toxicities, the Vel-CTD group showed a higher proportion of autonomic neuropathy, motor neuropathy, and sensory neuropathy compared to the Vel-CD group (each, p<0.05). Only three patients in the Vel-CTD group showed thrombotic events despite aspirin prophylaxis. The Vel-CD regimen inpatients with relapsed or refractory MM is an effective and more tolerable salvage therapy compared to Vel-CTD in terms of its comparable response rate and less severe of non-hematologic toxicities.

Durable remission with salvage second autotransplants in patients with multiple myeloma

BACKGROUND

High-dose chemotherapy with autologous hematopoietic cell transplant (auto-HCT) has been shown to improve survival in patients with newly diagnosed multiple myeloma. However, the role of salvage auto-HCT for relapsed patients, particularly in the era of novel therapeutics, is not well defined.

METHODS

The authors performed a retrospective analysis of all 44 myeloma patients (24 men, 20 women) who received a second auto-HCT as salvage between January 3, 1992 and November 4, 2008 at The University of Texas MD Anderson Cancer Center.

RESULTS

Median interval between the first and salvage auto-HCT was 30 months (range, 2-78 months). Median age at salvage HCT was 54 years (range, 38-73 years), and median number of salvage treatment regimens was 2 (range, 0-5). Eleven (25%) patients had high-risk chromosomal abnormalities on conventional cytogenetic studies between diagnosis and salvage auto-HCT. Ten patients (23%) experienced grade 3 or higher nonhematologic toxicity after the salvage auto-HCT. One patient died within 100 days, for a treatment-related mortality of 2%. Best responses after salvage chemotherapy + salvage auto-HCT were as follows: complete response (CR) + near CR, 11%; partial response, 79%; overall response rate, 90%. Eighteen (41%) patients received post auto-HCT maintenance therapy. Median follow-up from salvage HCT was 41 months. Kaplan-Meier estimates of median progression-free survival (PFS) and overall survival (OS) from time of salvage auto-HCT were 12.3 and 31.7 months, respectively. Median OS from the time of diagnosis was 75 months. In a fitted Bayesian multivariate model, shorter time to progression after first auto-HCT, greater number of prior therapies, African American race, and immunoglobulin G subtype were significantly associated with worse OS.

CONCLUSIONS

In selected myeloma patients, a second auto-HCT for salvage therapy is well tolerated, with acceptable toxicity. The overall response rate and PFS are comparable to other salvage regimens.

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.

Bortezomib (Velcade), rituximab, cyclophosphamide, and dexamethasone combination regimen is active as front-line therapy of low-grade non-Hodgkin lymphoma

OBJECTIVE

To evaluate the efficacy and toxicity of the combination of VRCD (velcade/rituximab/cyclophosphamide/dexamethasone) in chemotherapy-naïve low-grade non-Hodgkin lymphoma or patients with transplantation-ineligible mantle cells.

METHODS

The patients were treated with velcade, at 1.6 mg/m(2), on days 1, 8, 15, and 22 on every 35-day cycle. Rituximab was given at 375 mg/m(2) on the same days as velcade during cycle 1 and then only on day 1 in subsequent cycles. Dexamethasone was given orally at 40 mg on days 1, 2, 8, 9, 15, 16, 22, and 23. Cyclophosphamide was administered orally at 400 mg/m(2) on days 1-4. The patients had to meet criteria to initiate therapy and had to demonstrate adequate performance status and organ function.

RESULTS

Twelve patients were enrolled, after which the study was closed due to a lack of funding. The median age was 68 years (37-83 years), with 83% having stage III/IV disease. Five patients had marginal zone, 4 had follicular, 2 had small lymphocytic, and 1 had mantle cell histologies. The overall response rate was 90% (complete response, 54%). At a median follow-up of 22 months, 9 (75%) patients remain alive, and the median time to progression has not been reached. A third of the patients required dose reductions after a median of 6.5 cycles. No grade 3 or 4 peripheral neuropathy was witnessed.

CONCLUSIONS

Although the number of studied patients is small, VRCD appears safe and active as front-line therapy for low-grade non-Hodgkin lymphoma. Further studies are justified.

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.

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.

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.

Treatment of relapsed and refractory multiple myeloma in the era of novel agents

The introduction of the Immunomodulatory drugs (IMiDs) and proteasome inhibitors, used either as a single-agent or combined with classic anti-myeloma therapies, has improved the outcome for patients with relapsed myeloma. However, there is currently no generally accepted standard treatment for relapsed/refractory myeloma patients, partly because of the absence of trials comparing the efficacy of the novel agents in relapsed/refractory myeloma. Choice of a new treatment regimen depends on both patient and disease-specific characteristics. A lenalidomide-based regimen is the first choice in patients with neuropathy, while bortezomib has the highest efficacy in patients with renal insufficiency and is not associated with increased risk of thromboembolism. A second autologous stem cell transplantation (auto-SCT) can be applied in patients with a progression-free period of ≥ 18-24 months after the first auto-SCT. In high-risk relapse such as occurring early after auto-SCT consolidation with allogeneic SCT can be considered. In this review we provide an overview of the various salvage regimens and give recommendations for treatment of patients with relapsed/refractory myeloma in different clinical settings.