Salvage therapy of multiple myeloma: the new generation drugs

Mechanisms of Action of the New Antibodies in Use in Multiple Myeloma

Monoclonal antibodies (mAbs) directed against antigen-specific of multiple myeloma (MM) cells have Fc-dependent immune effector mechanisms, such as complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP), but the choice of the antigen is crucial for the development of effective immuno-therapy in MM. Recently new immunotherapeutic options in MM patients have been developed against different myeloma-related antigens as drug conjugate-antibody, bispecific T-cell engagers (BiTEs) and chimeric antigen receptor (CAR)-T cells. In this review, we will highlight the mechanism of action of immuno-therapy currently available in clinical practice to target CD38, SLAMF7, and BCMA, focusing on the biological role of the targets and on mechanisms of actions of the different immunotherapeutic approaches underlying their advantages and disadvantages with critical review of the literature data.

Novel dual LSD1/HDAC6 inhibitors for the treatment of multiple myeloma

Lysine specific demethylase 1 (LSD1) and HDAC6 are epigenetic proteins associated with several diseases, including cancer and combined inhibition of these proteins could be highly beneficial in treating some cancers such as AML, MM and solid tumors. Multiple myeloma (MM) is a challenging cancer with fast relapse rate where novel treatment options are the need of the hour. We have designed and developed novel, LSD1 and HDAC6 selective dual inhibitors to target MM. Our dual inhibitor compound 1 shows superior potency in multiple MM cell lines. In MM.1S xenograft model compound 1 shows superior efficacy compared to single agent LSD1 and HDAC6 inhibitors by oral administration and is well tolerated. Further evaluation of the molecule in other cancers is in progress.

Prevention of venous thromboembolic events occurring in myeloma patients treated with second-generation novel agents

Thrombosis and neoplasms are strictly linked, and the diagnosis of a malignancy is a relevant risk factor for venous thromboembolism (VTE). In particular, between gammopathies, the VTE risk is known to be increased in both monoclonal gammopathy of uncertain significance and in multiple myeloma, with a 3- and 9-fold increase respectively, when compared to the general population. The risk appears to be further increased in patients treated with immunomodulating drugs, such as thalidomide, especially when in combination with dexamethasone or conventional cytotoxic chemotherapies, and lenalidomide. In 2008 the International Myeloma Working Group put out thrombosis prophylaxis recommendations for myeloma patients treated with IMiDs. Current recommendations for thromboprophylaxis suggest the use of low-dose acetylsalicylic acid in patients with low risk for thrombosis and therapeutic dose anticoagulation with LMWH or warfarin for high-risk patients. However, these recommendations have been frequently not followed in the clinical practice, due to various reasons that involve the patients' will, the level of evidence of the recommendations and some selection biases in the studies that were taken as basis for writing down the indications. The new direct oral anticoagulants have been preliminarily evaluated for the prophylaxis of thrombotic events in IMiDs-treated myelomas, being promising, even if more expensive. Currently, the most reliable tool for a correct thrombotic risk stratification appears to be the complete clinical and anamnestic evaluation of the myeloma patients added to a strong physician awareness of the evidences that the literature contains until now.

Post-transplant consolidation based on combination of lenalidomide and proteasome inhibitors in multiple myeloma

Multiple myeloma (MM) is a hematological malignancy due to uncontrolled proliferation of neoplastic plasma cells in the bone marrow, associated to chromosomal instability and cytogenetic abnormalities, which could have an impact on prognosis. Response to treatment and survival of newly diagnosed myeloma patients is heterogeneous, with median overall survival ranging from two to more than ten years, due to clinical and biological factors. To warrant long-term control of disease, several strategies have been proposed in the last years, including short-term high-dose of treatment, named as consolidation, before maintenance. This review will discuss the role of consolidation in the current myeloma treatment landscape, and further improvements required to optimize tailored front-line therapy.

A Real-Life Survey of Venous Thromboembolic Events Occurring in Myeloma Patients Treated in Third Line with Second-Generation Novel Agents

Compared to the general population, patients with multiple myeloma (MM) have a nine-fold increased risk of developing venous thromboembolism (VTE). Little is known about VTE prophylaxis in relapsed/refractory (RR) MM patients treated with next generation anti-myeloma drugs, such as pomalidomide (Poma) and carfilzomib (K), and monoclonal antibodies daratumumab (Dara) and elotuzumab (Elo), alone or in combination with dexamethasone at high- (D, 40 mg/week) or low-dose (d, 20 mg/week). Here, we describe the incidence of VTE in a retrospective cohort of 112 consecutive relapsed and refractory myeloma (RRMM) patients who received a third line of treatment from April 2013 to February 2020. Anti-MM regimens included combinations of pomalidomide and dexamethasone (PomaD, N = 61), carfilzomib, lenalidomide and dexamethasone (KRd, N = 31), and elotuzumab, lenalidomide and dexamethasone (EloRd, N = 10), while the remaining 10 patients received daratumumab as a single agent. According to National Comprehnsive Cancer Network (NCCN), International Myeloma Working Group (IMWG) and 2015 European Myeloma Network (EMN) guidelines, 42 patients (38%) were classified as high-risk patients. According to the IMPEDE VTE score, 32 patients (28%) were classified as low-risk, with a score ≤ 3 (most of them in the PomaD and Dara group), 70 (63%) were classified as intermediate-risk, with a score of 4–7 (most of them in PomaD and KRd group), and 10 (9%) were classified as high-risk, with a score ≥8 (most of them in the PomaD group). All patients received a prophylaxis, consisting generally of low-doses of acetylsalicylic acid. VTE was recorded in 9% of our patients, all of them with an intermediate or high-risk IMPEDE score, treated with low doses aspirin (ASA). No VTE occurred in patients treated with daratumumab. Thus, our real-life experience documents that (1) in RRMM patients treated with continuative regimens of third line, the incidence of VTE is similar to the setting of newly-diagnosed patients; (2) many patients in real-life received prophylaxis with ASA, irrespective of the risk classification; (3) the IMPEDE VTE score seems to be more appropriate to define the risk categories. Randomized clinical trials are required to better define the VTE prophylaxis strategy in the RRMM setting.

Clinical Benefit of Long-Term Disease Control with Pomalidomide and Dexamethasone in Relapsed/Refractory Multiple Myeloma Patients

Background: We retrospectively analysed relapsed/refractory MM (RRMM) patients treated with pomalidomide and dexamethasone (PomaD) either in real life, or previously enrolled in an interventional (STRATUS, MM-010) or currently enrolled in an observational study (MM-015) to provide further insights on safety and tolerability and clinical efficacy. Methods: Between July 2013 and July 2018, 76 RRMM patients (including 33 double refractory MM) received pomalidomide 4 mg daily given orally on days 1–21 of each 28-day cycle, and dexamethasone 40 mg weekly (≤75 years) or 20 mg weekly for patients aged > 75 years. In nine patients a third agent was added to increase the response: Cyclophosphamide (in two fit patients) or clarithromycin (in seven frail patients). Patients received subcutaneous filgrastim as part of the prophylaxis regimen for neutropenia. Results: A median number of six (range 2–21) PomaD cycles were given. The regimen was well tolerated with grade 3–4 haematological and non-haematological adverse events in 39 (51%) and 25 (33%) patients, respectively. In patients who developed serious AE, pomalidomide dose reduction (11%, 14%) or definitive discontinuation (18%, 23%) were applied. All patients have been evaluated for response within the first two cycles. The disease control rate (DCR), i.e., those patients that had a response equal or better than stable disease (≥ SD), was high (89%), with 44% overall response rate (ORR) after six cycles. The achieved best responses were complete remission (CR, 5%), very good partial remission (VGPR, 4%), partial remission (PR, 35%), minimal response (MR, 7%), and stable disease (SD, 38%). After a median follow up of 19.6 months, median progression free survival was 9.4 months, and overall survival (OS) was 19.02 months. Univariate analysis showed that double refractory patients, or who received more than three previous lines had shorter PFS. At 18 months, regardless of the depth of response, patients with a disease control of at least six months, defined as maintenance of a best clinical and/or biochemical response to treatment for almost six months, had prolonged PFS (35.3% versus 20.6%, p = 0.0003) and OS (81.2% versus 15.9%, p < 0.0001) Conclusions: Our findings indicate that PomaD is a safe and well-tolerated regimen in real-life, associated with prolonged PFS and OS with acceptable toxicity. Moreover, Pd induced disease control in most intensively pre-treated patients and some of them achieved longer PFS than that obtained with the previous treatment.

Feasibility, Tolerability and Efficacy of Carfilzomib in Combination with Lenalidomide and Dexamethasone in Relapsed Refractory Myeloma Patients: A Retrospective Real-Life Survey of the Sicilian Myeloma Network

Background: The ASPIRE (NCT01080391) phase 3 trial showed the efficacy of carfilzomib, lenalidomide and dexamethasone (KRd) triplet for relapse and refractory multiple myeloma (RRMM). However, little is known about safety and efficacy of KRd outside a clinical trial context. Methods: Herein we report real life results of KRd given to 130 RRMM patients from 12 Sicilian Centers. Results: Median age was 62 years; patients had received a median of two previous lines of treatment (range 1–10) and 52% were refractory to previous treatment. Median number of KRd cycles was 12 (2–29), with a mean duration of treatment of 12 months; 21 patients had received at least 18 cycles. Overall response rate was 61%, including 18% complete response. Median PFS was 22.9 months, median OS was not reached. Creatinine clearance >30 mL/min, quality of the best achieved response and standard Fluorescence In Situ Hybridization (FISH) risk were independent predictors of favorable outcome. Patients who received the full-dosage of carfilzomib in the first two cycles had a better outcome. Conclusions: KRd was effective and well tolerated and in a considerable proportion of patients, therapy continued beyond the 18th cycle. The finding of a better outcome in patients with the higher cumulative dose of carfilzomib in the first two cycle encourages to maintain the maximum tolerated dose.

A phase 2 safety study of accelerated elotuzumab infusion, over less than 1 h, in combination with lenalidomide and dexamethasone, in patients with multiple myeloma

Elotuzumab, an immunostimulatory SLAMF7-targeting monoclonal antibody, induces myeloma cell death with minimal effects on normal tissue. In a previous phase 3 study in patients with relapsed/refractory multiple myeloma (RRMM), elotuzumab (10 mg/kg, ∼3-h infusion), combined with lenalidomide and dexamethasone, demonstrated durable efficacy and acceptable safety; 10% (33/321) of patients had infusion reactions (IRs; Grade 1/2: 29; Grade 3: 4). This phase 2 study (NCT02159365) investigated an accelerated infusion schedule in 70 patients with newly diagnosed multiple myeloma or RRMM. The primary endpoint was cumulative incidence of Grade 3/4 IRs by completion of treatment Cycle 2. Dosing comprised elotuzumab 10 mg/kg intravenously (weekly, Cycles 1-2; biweekly, Cycles 3+), lenalidomide 25 mg (daily, Days 1-21), and dexamethasone (28 mg orally and 8 mg intravenously, weekly, Cycles 1-2; 40 mg orally, weekly, Cycles 3+), in 28-day cycles. Premedication with diphenhydramine, acetaminophen, and ranitidine (or their equivalents) was given as in previous studies. If no IRs occurred, infusion rate was increased in Cycle 1 from 0.5 to 2 mL/min during dose 1 (∼2 h 50 min duration) to 5 mL/min for the entire infusion by dose 3 and also during all subsequent infusions (∼1-h duration). Median number of treatment cycles was six. No Grade 3/4 IRs occurred; only one Grade 1 and one Grade 2 IR occurred, both during the first infusion. These data support the safety of a faster infusion of elotuzumab administered over ∼1 h by the third dose, providing a more convenient alternative dosing option for patients.

Benefit of continuous treatment for responders with newly diagnosed multiple myeloma in the randomized FIRST trial

The phase 3, randomized Frontline Investigation of Revlimid and Dexamethasone Versus Standard Thalidomide (FIRST) trial investigating lenalidomide plus low-dose dexamethasone until disease progression (Rd continuous) vs melphalan, prednisone and thalidomide for 12 cycles (MPT) and Rd for 18 cycles (Rd18) in transplant-ineligible patients with newly diagnosed multiple myeloma (NDMM) showed that Rd continuous prolonged progression-free survival and overall survival compared with MPT. A subanalysis of the FIRST trial was conducted to determine the benefits of Rd continuous in patients with NDMM based on depth of response. Patients randomized 1:1:1 to Rd continuous, Rd18 or MPT were divided into subgroups based on best response: complete response (CR; n=290), ⩾very good partial response (VGPR; n=679), ⩾partial response (PR; n=1 225) or ⩽stable disease (n=299). Over 13% of patients receiving Rd continuous who achieved ⩾VGPR as best response did so beyond 18 months of treatment. Rd continuous reduced the risk of progression or death by 67%, 51% and 35% vs MPT in patients with CR, ⩾VGPR and ⩾PR, respectively. Similarly, Rd continuous reduced the risk of progression or death by 61%, 54% and 38% vs Rd18 in patients with CR, ⩾VGPR and ⩾PR, respectively. In patients with CR, ⩾VGPR or ⩾PR, 4-year survival rates in the Rd continuous arm (81.1%, 73.1% or 64.6%, respectively) were higher vs MPT (70.8%, 59.8% or 57.2%, respectively) and similar vs Rd18 (76.5%, 67.7% and 62.5%, respectively). Rd continuous improved efficacy outcomes in all responding patients, including those with CR, compared with fixed duration treatment.

Low-dose lenalidomide and dexamethasone combination treatment in elderly patients with relapsed and refractory multiple myeloma

OBJECTIVE

This study investigated the efficacy and safety of low-dose lenalidomide combined with dexamethasone in elderly patients with relapsed and refractory multiple myeloma (MM).

METHODS

Thirty-two elderly patients with refractory and recurrent MM (median age: 64 years) were treated with low-dose lenalidomide (LD-R) combined with dexamethasone (D). LD-R (10 mg/d) was administered orally for 21 days and D (40 mg/d) was administered twice a day on days 1-4, 9-12, and 17-20. The treatment lasted 2-8 28-day cycles.

RESULTS

After two cycles, the complete, very good partial, and partial remission rates were 12.5% (4/32), 25.0% (8/32), and 34.4% (11/32), respectively. The overall response rate was 71.9% (23/32). After a 24-month follow-up, 23 patients responded to therapy, three were in complete remission, four were stable, and 16 exhibited disease progression. In addition, median time-to-progression was 13 months. Observed side effects were hypodynamia, gastrointestinal reaction, peripheral neuritis, and mild hypocytosis.

CONCLUSION

Low-dose lenalidomide in combination with dexamethasone is an effective and safe treatment for relapsed and refractory MM in elderly patients.

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance.

Elotuzumab in combination with lenalidomide and dexamethasone in patients with relapsed multiple myeloma: final phase 2 results from the randomised, open-label, phase 1b-2 dose-escalation study

BACKGROUND

Elotuzumab, an immunostimulatory monoclonal antibody targeting signalling lymphocytic activation molecule (SLAM) family member 7 (SLAMF7), selectively kills SLAMF7-expressing myeloma cells through direct activation and engagement of the innate immune system, and thus might have clinical benefit in the treatment of myeloma. In phase 1 of this phase 1b-2 study, 82% of patients with relapsed multiple myeloma who were given elotuzumab plus lenalidomide and dexamethasone achieved an overall response. Here we report the final phase 2 results.

METHODS

We did this randomised, multicentre, open-label, dose-escalation study (1703) at 17 hospitals in the USA, Canada, France, and Germany. Patients aged at least 18 years with confirmed, relapsed multiple myeloma, Eastern Cooperative Oncology Group performance status 0-2, and one to three previous therapies but no previous lenalidomide were eligible for phase 2. We randomly assigned patients (1:1) to either 10 mg/kg or 20 mg/kg intravenous elotuzumab plus oral lenalidomide (25 mg) and dexamethasone (40 mg). We stratified patients on the basis of the number of previous therapies (one versus two or three), and status of previous treatment with immunomodulatory drugs (yes or no), and used permuted block randomisation with a block size of four. Treatment was given in 28-day cycles until disease progression or unacceptable toxic effects occurred (elotuzumab was given on days 1, 8, 15, and 22 for cycles 1 to 2 and days 1 and 15 for subsequent cycles; lenalidomide was given on days 1-21 and dexamethasone once per week). The primary endpoint was the proportion of patients who achieved an objective response according to International Myeloma Working Group criteria. Primary analyses were done in the intention-to-treat population, and safety was analysed in all patients who received at least one dose of study drugs. This study is registered with ClinicalTrials.gov, number NCT00742560.

FINDINGS

Between Jan 4, 2010, and Dec 21, 2010, we recruited and randomly assigned 73 patients to elotuzumab (36 to 10 mg/kg, 37 to 20 mg/kg). At data cutoff (Jan 16, 2014), 13 patients remained on treatment (six on 10 mg/kg, seven on 20 mg/kg). 61 (84%) patients achieved an objective response (33 [92%] with 10 mg/kg, 28 [76%] with 20 mg/kg); 31 (42%) a very good partial response (17 [47%] with 10 mg/kg, 14 [38%] with 20 mg/kg); and 20 (27%) a partial response (10 [28%] with 10 mg/kg, 10 [27%] with 20 mg/kg). The most common treatment-emergent adverse events of any grade were diarrhoea (48 [66%]), muscle spasms (45 [62%]), and fatigue (41 [56%]). 57 (78%) patients had grade 3-4 events, the most common of which were lymphopenia (15 [21%]) and neutropenia (14 [19%]). Three deaths occurred, none related to the study drugs.

INTERPRETATION

Elotuzumab combined with lenalidomide and dexamethasone in patients with relapsed multiple myeloma showed acceptable safety and efficacy that seems better than that previously noted with lenalidomide and dexamethasone only. Phase 3 trials are in progress.

FUNDING

Bristol-Myers Squibb, AbbVie Biotherapeutics.