Lenalidomide, bendamustine and prednisolone exhibits a favourable safety and efficacy profile in relapsed or refractory multiple myeloma: final results of a phase 1 clinical trial OSHO - #077

Bendamustine-Based Regimens as Salvage Therapy in Refractory/Relapsed Multiple Myeloma Patients: A Retrospective Real-Life Analysis by the Polish Myeloma Group

Multiple myeloma (MM) is an incurable disease and patients become refractory to the treatment in the course of the disease. Bendamustine-based regimens containing steroids and other agents are among the therapeutic options offered to MM patients. Here, we investigated the safety and the efficacy of bendamustine used in patients with refractory/relapsed MM (RRMM). The patients were treated with bendamustine and steroids (n = 52) or bendamustine, steroids and immunomodulatory agents or proteasome inhibitors (n = 53). Response rates, progression-free survival (PFS), overall survival (OS) and frequency of adverse events were compared between both study groups. Most efficacy measurements were better in patients treated with three-drug regimens: overall response rate (55% versus 37%, p = 0.062), median PFS (9 months versus 4 months, p < 0.001), median OS survival (18 months versus 12 months, p = 0.679). The benefit from combining bendamustine and steroids with an additional agent was found in subgroups previously treated with both lenalidmide and bortezomib, with stem cell transplant and with more than two previous therapy lines. Toxicity was similar in both study groups and bendamustine-based therapies were generally well-tolerated. Our study suggests that bendamustine may be an effective treatment for patients with RRMM. Three-drug regimens containing bendamustine, steroids and novel agents produced better outcomes and had acceptable toxicity. The efficacy of bendamustine combined with steroids was limited.

Current and Novel Alkylators in Multiple Myeloma

A large number of novel treatments for myeloma have been developed and approved; however, alkylating drugs continue to be part of standard regimens. Additionally, novel alkylators are currently being developed. We performed a non-systematized literary search for relevant papers and communications at large conferences, as well as exploiting the authors' knowledge of the field, to review the history, current use and novel concepts around the traditional alkylators cyclophosphamide, bendamustine and melphalan and current data on the newly developed pro-drug melflufen. Even in the era of targeted treatment and personalized medicine, alkylating drugs continue to be part of the standard-of-care in myeloma, and new alkylators are coming to the market.

Novel Agents in Multiple Myeloma

The therapeutic landscape of multiple myeloma (MM) has dramatically changed in the last 15 years with the advent of immunomodulatory drugs and proteasome inhibitors. However, majority of MM patients relapse, and new therapies are needed. Various agents with diverse mechanisms of action and distinct targets, including cellular therapies, monoclonal antibodies, and small molecules, are currently under investigation. In this review, we report novel drugs recently approved or under advanced investigation that will likely be incorporated in the future as new standard for MM treatment, focusing on their mechanisms of action, cellular targets, and stage of development.

Venous thromboembolism risk with contemporary lenalidomide-based regimens despite thromboprophylaxis in multiple myeloma: A systematic review and meta-analysis

BACKGROUND

Thromboprophylaxis is routinely used with lenalidomide-based regimens in multiple myeloma because of a substantial risk of venous thromboembolism (VTE). However, little is known about the incidence of VTE with contemporary lenalidomide-based regimens. The objective of the current study was to estimate the incidence of VTE despite thromboprophylaxis with currently used lenalidomide-based regimens in patients with myeloma.

METHODS

The Ovid MEDLINE, Embase, and Cochrane databases were queried from study inception to January 2019 for keywords to cover the following concepts: "lenalidomide," "venous thromboembolism," and "multiple myeloma." Phase 1, 2, and 3 clinical trials evaluating lenalidomide-based regimens with thromboprophylaxis were included. The pooled incidence rate of VTE was estimated using a random-effects model.

RESULTS

The search generated 1372 citations, with 51 clinical trials and 9069 patients included for analysis. The most common thromboprophylaxis agents were aspirin, low-molecular-weight heparin or warfarin, administered either per risk-stratification or at investigators' discretion. The pooled incidence of VTE in trials of patients who had newly diagnosed and relapsed/refractory myeloma was 6.2% (95% CI, 5.4%-7.1%) over median treatment durations ranging from 2 to 34 cycles, which translated into 1.2 VTE events per 100 patient-cycles (95% CI, 0.9-1.7 VTE events per 100 patient-cycles). Among contemporary regimens, the risk of VTE was low with combined lenalidomide and low-dose dexamethasone (0.2 [95% CI, 0.1-0.6] events/100 patient-cycles) and lenalidomide maintenance (0.0 [95% CI, 0.0-0.7] events per 100 patient-cycles). VTE risk was higher with combined lenalidomide and low-dose dexamethasone plus proteasome inhibitors (1.3 [95% CI, 0.7-2.3] events per 100 patient-cycles).

CONCLUSIONS

Despite adequate thromboprophylaxis, lenalidomide-based regimens have a substantial risk of VTE in controlled clinical trial settings. Further studies are needed on new thromboprophylaxis strategies with regimens that have a high VTE risk.

Lenalidomide in combination with bendamustine and prednisolone in relapsed/refractory multiple myeloma: results of a phase 2 clinical trial (OSHO-#077)

INTRODUCTION

While lenalidomide monotherapy is established for relapsed and/or refractory multiple myeloma (MM) treatment, combination therapies including lenalidomide are still under investigation in a number of phase 2/3 studies. In the current study, a treatment regime of lenalidomide (Revlimid^®), bendamustine and prednisolone (RBP) was tested in patients with relapsed/refractory MM.

METHODS

In the previously completed phase 1 study RBP with a dose of 75 mg/m² bendamustine days 1-2, prednisolone 100 mg days 1-4 and 25 mg lenalidomide days 1-21 was well tolerated.

RESULTS

Between July 2011 and September 2013, 25 patients were included in this analysis. The median number of previous treatments was 1 (range 1-2). Twenty-two patients (88%) responded after at least two cycles of RBP (one sCR, five nCR, eight VGPR and eight PR). The median time to first haematological response was 28 days, and median time to best response was 56 days. Due to increased haematological toxicity a dose reduction in most patients required in subsequent cycles of therapy. The median progression-free and overall survival was 22 and 38 months, respectively. In conclusion RBP is a highly effective therapy for patients with relapsed/refractory MM. In contrast to our phase 1 study, dose reduction was necessary in many patients because of haematological toxicity.

Clinical Outcomes Related to the Use of Bendamustine Therapy for Multiple Myeloma Patients Relapsed/Refractory to Immunomodulatory Drugs and Proteasome Inhibitors

Objective:

Multiple myeloma patients who are relapsed or refractory to both proteasome inhibitors (PIs) and immunomodulatory drugs (IMiDs) have been reported to have poor outcomes. Bendamustine has been reported to have an antitumor effect in newly diagnosed as well as relapsed/refractory multiple myeloma (RRMM). The aim of this retrospective study was to evaluate the efficacy of bendamustine therapy in heavily pretreated MM patients who were refractory to PIs and IMiDs.

Materials and Methods:

Nineteen RRMM patients treated either with bendamustine and steroids (n=13) or a combination of bendamustine with novel drugs (n=6) were included. The median number of previous treatment lines was 5 (minimum-maximum: 3-8) and median time from diagnosis was 6 years (minimum-maximum: 1-16). All of the patients were resistant to at least one of the IMiDs and one of the PIs. Bendamustine was given at doses ranging from 90 mg/m² to 120 mg/m² on days 1 and 2 of 28-day cycles.

Results:

A median of 2 (minimum-maximum: 1-8) treatment cycles was administered per patient. The toxicity of bendamustine was mild and mostly of hematological origin. No complete remission was achieved. There was partial remission and stable disease in 21% and 11% of the patients, respectively. Sixty-eight percent of patients had progressive disease. The median progression-free survival and overall survival was 2 and 4 months, respectively.

Conclusion:

Bendamustine therapy was well tolerated but showed limited anti-myeloma activity in heavily pretreated patients who were refractory to IMiDs and PIs.

An update in treatment options for multiple myeloma in nontransplant eligible patients

INTRODUCTION

Despite the fact that multiple myeloma (MM) is still an incurable disease, the outcome of patients who are eligible and ineligible for high-dose therapy has dramatically improved with the introduction of novel agents, that is proteasome inhibitors (PIs) and immunomodulatory agents (IMiDs). However, this improvement is often not seen in elderly patients (above 75 years).

AREAS COVERED

This review will focus on the impact of known prognostic factors in elderly MM patients, and risk factors to identify frail elderly patients. Furthermore, data on known and novel PIs and IMiDs, as well as data on other promising novel treatment strategies, chosen based on current practice and anticipated timely approval, will be discussed. Novel treatment strategies include the use of monoclonal antibodies, such as elotuzumab, daratumumab, SAR650984 and more targeted therapies, such as histone deacetylase inhibitors, kinesin spindle protein inhibitors, and selective inhibitors of nuclear export.

EXPERT OPINION

Besides efficacy of treatment, toxicity and quality of life play an important role in treatment choice. Treatment and treatment dosing for the frail elderly as well as risk factors to identify the frail elderly require further consideration, as these patients frequently do not benefit from these novel agents due to early discontinuation of treatment due to toxicity.

Bendamustine in multiple myeloma

The advent of high-dose melphalan with autologous stem-cell transplantation (ASCT), the availability of novel agents such as thalidomide, lenalidomide (immunomodulatory drugs or IMiDs) and bortezomib (proteasome inhibitor) and improvements in supportive care have allowed to increase overall survival in multiple myeloma (MM) patients; nevertheless, MM remains an incurable pathology. For this reason, newer agents are required for continued disease control. Bendamustine is an old drug rediscovered in the last decade. In fact, its unique mechanism of action with structural similarities to both alkylating agents and antimetabolities, but which is not cross-resistant to alkylating agents, has reawakened interest in the use of this drug in the treatment of MM. Studies have proven the safety and efficacy of bendamustine administered alone or in combination with new drugs in both upfront and relapse/refractory settings of MM patients, including those with renal impairment. Moreover, bendamustine has been successfully used as conditioning for autologous stem-cell transplantation. Finally, the use of bendamustine does not compromise peripheral blood stem-cell collection. This drug is generally well tolerated, with the majority of adverse events being due to myelosuppression. Non-haematological adverse events are infrequent and usually mild.

Bendamustine, thalidomide and dexamethasone combination therapy for relapsed/refractory myeloma patients: results of the MUKone randomized dose selection trial

There is a significant unmet need in effective therapy for relapsed myeloma patients once they become refractory to bortezomib and lenalidomide. While data from the front line setting suggest bendamustine is superior to melphalan, there is no information defining optimal bendamustine dose in multiply-treated patients. We report a multi-centre randomized two-stage phase 2 trial simultaneously assessing deliverability and activity of two doses of bendamustine (60 mg/m2 vs. 100 mg/m2) days 1 and 8, thalidomide (100 mg) days 1-21 and low dose dexamethasone (20 mg) days 1, 8, 15 and 22 of a 28-d cycle. Ninety-four relapsing patients were treated on trial, with a median three prior treatment lines. A pre-planned interim deliverability and activity assessment led to closure of the 100 mg/m2 arm due to excess cytopenias, and led to amendment of entry criteria for cytopenias. Non-haematological toxicities including thromboembolism and neurotoxicity were infrequent. In the 60 mg/m2 arm, treatment was deliverable in 61.1% subjects and the partial response rate was 46.3% in the study eligible population, with 7.5 months progression-free survival. This study demonstrates bendamustine at 60 mg/m2 twice per month with thalidomide and dexamethasone is deliverable for repeated cycles in heavily pre-treated myeloma patients and has substantial clinical activity.

Bendamustine in combination with thalidomide and dexamethasone is a viable salvage option in myeloma relapsed and/or refractory to bortezomib and lenalidomide

Treatment options are limited in myeloma relapsed or refractory to both bortezomib and lenalidomide (double-relapsed/refractory multiple myeloma; DRMM). Bendamustine is an antitumour agent that has efficacy in relapsed myeloma. We retrospectively analysed data from 30 DRMM patients who received a combination of bendamustine, thalidomide and dexamethasone (BTD) in 28-day treatment cycles. Bendamustine was administered with a cumulative dose of up to 200 mg/m(2). Thalidomide (50-150 mg) was given daily as tolerated, and dexamethasone was given at an equivalent dose of up to 160 mg per cycle. A median of 5 (2-9) treatment cycles were administered per patient. Twenty-six patients (87 %) achieved stable disease or better. At a median follow-up time of 12.1 (2.3-21.5) months, median (95 % CI) progression-free survival and overall survival were 4.0 (2.6-5.3) months and 7.2 (5.2-9.2) months, respectively. The most common grade 3-4 adverse events were haematological: anaemia (n = 8, 34.8 %), neutropenia (n = 16, 69.6 %) and thrombocytopenia (n = 10, 43.5 %). Non-haematological toxicities included pain (n = 3, 13.0 %), infection (n = 7, 30.4 %) and sensory neuropathy (n = 1, 4.3 %). We propose that BTD is a viable salvage treatment option for DRMM patients.

Salvage therapy of multiple myeloma: the new generation drugs

During the past decade, overall results of treatment of multiple myeloma (MM) have been improved and survival curves are now significantly better with respect to those obtained with historical treatment. These improvements are linked to a deeper knowledge of the biology of disease and to the introduction in clinical practice of drugs with different mechanism of action such as proteasome inhibitors and immunomodulatory drugs (IMiDs). However, MM remains in most cases an incurable disease. For patients who relapse after treatment with novel agents, the prognosis is dismal and new drugs and therapeutic strategies are required for continued disease control. In this review, we summarize new insights in salvage therapy for relapsed/refractory MM as emerging from recent clinical trials exploring the activity of bendamustine, new generation proteasome inhibitors, novel IMiDs, monoclonal antibodies, and drugs interfering with growth pathways.

New drugs and novel mechanisms of action in multiple myeloma in 2013: a report from the International Myeloma Working Group (IMWG)

Treatment in medical oncology is gradually shifting from the use of nonspecific chemotherapeutic agents toward an era of novel targeted therapy in which drugs and their combinations target specific aspects of the biology of tumor cells. Multiple myeloma (MM) has become one of the best examples in this regard, reflected in the identification of new pathogenic mechanisms, together with the development of novel drugs that are being explored from the preclinical setting to the early phases of clinical development. We review the biological rationale for the use of the most important new agents for treating MM and summarize their clinical activity in an increasingly busy field. First, we discuss data from already approved and active agents (including second- and third-generation proteasome inhibitors (PIs), immunomodulatory agents and alkylators). Next, we focus on agents with novel mechanisms of action, such as monoclonal antibodies (MoAbs), cell cycle-specific drugs, deacetylase inhibitors, agents acting on the unfolded protein response, signaling transduction pathway inhibitors and kinase inhibitors. Among this plethora of new agents or mechanisms, some are specially promising: anti-CD38 MoAb, such as daratumumab, are the first antibodies with clinical activity as single agents in MM. Moreover, the kinesin spindle protein inhibitor Arry-520 is effective in monotherapy as well as in combination with dexamethasone in heavily pretreated patients. Immunotherapy against MM is also being explored, and probably the most attractive example of this approach is the combination of the anti-CS1 MoAb elotuzumab with lenalidomide and dexamethasone, which has produced exciting results in the relapsed/refractory setting.

Bendamustine: the remedy that came in from the cold

In this issue of Blood, Ludwig and colleagues present the data of a phase 2 clinical trial showing that bendamustine, bortezomib, and dexamethasone (BBD) is a very active and well-tolerated regimen in patients with relapsed or refractory multiple myeloma.1 More importantly, BBD overcomes the adverse prognosis in patients with high-risk cytogenetics.

Future agents and treatment directions in multiple myeloma

The development of bortezomib and immunomodulatory agents resulted in a revolution in the treatment of multiple myeloma (MM). Moreover, second-generation proteasome inhibitors (carfilzomib) and immunomodulatory agents (pomalidomide) have recently been approved. Nevertheless, the incurability of this disease requires other drugs with different mechanisms of action to either prolong the survival of patients refractory to current therapies, or achieve cure. Active research has been done exploring the pathogenesis of MM and searching for novel, druggable targets. In this regard, some of these novel agents seem promising, such as monoclonal antibodies (anti-CD38 - daratumumab or anti-CS1 - elotuzumab) or the kinesin protein inhibitor Arry-520. Other agents under investigation are kinase inhibitors, signaling pathways inhibitors or deacetylase inhibitors. With so many novel agents under investigation, future therapy in MM will probably involve the combined use of the already approved drugs with some of those newly discovered.

Bendamustine-bortezomib-dexamethasone is an active and well-tolerated regimen in patients with relapsed or refractory multiple myeloma

Bendamustine with bortezomib and dexamethasone was evaluated in 79 patients with relapsed/refractory multiple myeloma. Median age was 64 years, and patients had a median of 2 prior treatment lines (range, 1 to 6 lines). Bendamustine 70 mg/m(2) days 1 and 4; bortezomib 1.3 mg/m(2) intravenously days 1, 4, 8, and 11; and dexamethasone 20 mg days 1, 4, 8, and 11 once every 28 days was given for up to 8 cycles. Primary end point was overall response rate (ORR). Secondary end points were progression-free survival (PFS), overall survival, time to response, and toxicity. ORR was 60.8%, and when minor responses were included, 75.9%. Median time to response was 31 days. ORR rate was similar in patients previously exposed to bortezomib, lenalidomide, and bortezomib plus lenalidomide. PFS was 9.7 and OS was 25.6 months. Multivariate analysis showed high lactate dehydrogenase, ≥3 prior treatment lines, and low platelet counts correlating with short survival. Grade 3/4 thrombocytopenia was noted in 38%, and grade 3/4/5 infections were noted in 23%. Grade ≤2 polyneuropathy increased from 19% at baseline to 52% at cycle 8 and grade 4, from 0% to 7%. Bendamustine-bortezomib-dexamethasone is active and well tolerated in patients with relapsed/refractory myeloma. This trial was registered in the EudraCT database as No. 2008-006421-13.

An old drug with a new future: bendamustine in multiple myeloma

INTRODUCTION

Bendamustine is a unique bifunctional alkylating agent with promising activity in multiple myeloma (MM). It is currently licensed in Europe for use as frontline treatment with prednisolone for patients with MM who are unsuitable for transplantation and who are contraindicated for thalidomide and bortezomib therapy.

AREAS COVERED

Studies evaluating the safety and efficacy of bendamustine administered alone or in combination in both the upfront and relapse settings of MM patients, including those with renal insufficiency, were reviewed. The use of bendamustine as conditioning for autologous stem-cell transplantation and the possibility of stem-cell mobilization after bendamustine therapy are discussed.

EXPERT OPINION

Bendamustine seems to be efficacious either in monotherapy or in combination with other drugs in previously treated or untreated patients. This is due to its unique mechanism of action including its ability to activate apoptosis and inhibit mitotic checkpoints, making it potentially more effective than other alkylating agents. Moreover, it has an acceptable toxicity profile and is suitable for patients with renal impairment. Finally, this drug does not seem to compromise the possibility of achieving a stem-cell mobilization. Nonetheless, data from Phase III studies demonstrating its effectiveness in terms of overall survival are not yet available.

Current and emerging treatment options for patients with relapsed myeloma

Multiple myeloma (MM) is a neoplastic disorder. It results from proliferation of clonal plasma cells in bone marrow with production of monoclonal proteins, which are detectable in serum or urine. MM is clinically characterized by destructive bone lesions, anemia, hypercalcemia and renal insufficiency. Its prognosis is severe, with a median survival after diagnosis of approximately 3 years due to frequent relapses. Treatments for patients with relapsed/refractory MM include hematopoietic cell transplantation, a rechallenge using a previous chemotherapy regimen or a trial of a new regimen. The introduction of new drugs such as thalidomide, lenalidomide and bortezomib has markedly improved MM outcomes. When relapse occurs, the clinician's challenge is to select the optimal treatment for each patient while balancing efficacy and toxicity. Patients with indolent relapse can be first treated with a 2-drug or a 3-drug combination. Patients with more aggressive relapse often require therapy with a combination of multiple active agents. Autologous stem cell transplantation should be considered as salvage therapy at first relapse for patients who have cryopreserved stem cells early in the disease course. The aim of this review is to provide an overview on the pharmacological and molecular action of treatments used for patients with relapsed/refractory multiple myeloma.