Pomalidomide, bortezomib and low-dose dexamethasone in lenalidomide-refractory and proteasome inhibitor-exposed myeloma

Multiple myeloma refractory to lenalidomide: A systematic literature review of trials and real-world evidence

The growing use of frontline lenalidomide treatment in multiple myeloma (MM) is increasing the proportion of lenalidomide-refractory patients, which may limit the efficacy of subsequent lines of treatment (LOT). This systematic literature review (January 2008-October 2023) of clinical trials (CT) and real-world studies (RW) assessed treatment outcomes in adults with relapsed/refractory MM (RRMM) who were previously treated with ≥1 LOT, progressed and were lenalidomide-refractory. Medline, EMBASE and additional electronic databases were searched for articles published in English. Primary outcomes included progression-free survival (PFS), overall survival (OS) and overall/objective response rate (ORR); 24 CT and 19 RW were included. For CT, the population-weighted mean of median PFS (CT = 14) and OS (CT = 6) were shorter in the lenalidomide-refractory cohort (months: 8.8 [n = 2699] and 21.7 [n = 1066], respectively) than the intent-to-treat population (months: 13.8 [n = 5380] and 35.9 [n = 2264], respectively); the population-weighted (N = 2142) mean ORR for lenalidomide-refractory patients (CT = 18) was 56.0%. RW reported considerable variation in PFS (RW = 7), OS (RW = 8) and ORR (RW = 8); and median PFS (RW = 2; months) was lower in lenalidomide/bortezomib-refractory (5.5/5.5; n = 81/n = 25) versus lenalidomide-refractory (7.3/8.0; n = 81/n = 61) patients. These data provide evidence that clinical trials and real-world outcomes are suboptimal in lenalidomide-refractory patients with RRMM, highlighting the need to improve treatment options for this population.

Skin Rash as a Side Effect of Bortezomib: A Case Report

Bortezomib is a novel proteasome inhibitor widely used in the treatment of multiple myeloma, especially in the case of recurrent, relapsing, or refractory myeloma. Its common side effects include nausea, vomiting, neuropathic pain, and hemorrhage. Cutaneous manifestations are considered rare. Here we report a case of a 72-year-old female patient, and a known case of multiple myeloma on VRD protocol (bortezomib [Velcade] combined with lenalidominde [Revlimid] and dexamethasone) after relapse. The patient presented with a complaint of raised, itchy, erythematous skin rash, starting in the soles and palms and then spreading to the whole body. A skin biopsy confirmed that the lesions were due to an allergic reaction. The patient was admitted as a case of sepsis and died. Skin rash is considered a rare side effect of bortezomib, with variable presentation and onset. The mainstay of treatment is corticosteroids.

Proteasome inhibition in combination with immunotherapies: State-of-the-Art in multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell disorder accounting for around 1.8% of all neoplastic diseases. Nowadays, clinicians have a broad arsenal of drugs at their disposal for the treatment of MM, such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, bispecific antibodies, CAR T-cell therapies and antibody-drug conjugates. In this paper we briefly highlight essential clinical elements relating to proteasome inhibitors, such as bortezomib, carfilzomib and ixazomib. Studies suggest that the early use of immunotherapy may improve outcomes significantly. Therefore, in our review we specifically focus on the combination therapy of proteasome inhibitors with novel immunotherapies and/or transplant. A high number of patients develop PI resistance. Thus, we also review new generation PIs, such as marizomib, oprozomib (ONX0912) and delanzomib (CEP-18770) and their combinations with immunotherapies.

Lenalidomide in Multiple Myeloma: Review of Resistance Mechanisms, Current Treatment Strategies and Future Perspectives

Multiple myeloma (MM) is the second most common hematologic malignancy, accounting for approximately 1% of all cancers. Despite the initial poor prognosis for MM patients, their life expectancy has improved significantly with the development of novel agents. Immunomodulatory drugs (IMiDs) are widely used in MM therapy. Their implementation has been a milestone in improving the clinical outcomes of patients. The first molecule belonging to the IMiDs was thalidomide. Subsequently, its novel derivatives, lenalidomide (LEN) and pomalidomide (POM), were implemented. Almost all MM patients are exposed to LEN, which is the most commonly used IMiD. Despite the potent anti-MM activity of LEN, some patients eventually relapse and become LEN-resistant. Drug resistance is one of the greatest challenges of modern oncology and has become the main cause of cancer treatment failures. The number of patients receiving LEN is increasing, hence the problem of LEN resistance has become a great obstacle for hematologists worldwide. In this review, we intended to shed more light on the pathophysiology of LEN resistance in MM, with particular emphasis on the molecular background. Moreover, we have briefly summarized strategies to overcome LEN resistance and we have outlined future directions.

Phase I study of plitidepsin in combination with bortezomib and dexamethasone in patients with relapsed/refractory multiple myeloma

Previous studies showed antitumor activity for plitidepsin plus dexamethasone (DXM) in relapsed/refractory multiple myeloma (r/r MM), and in vitro synergism with bortezomib (BTZ) or DXM against MM cells. This phase I trial evaluated plitidepsin (3-h intravenous infusion Day 1 and 15), BTZ (subcutaneous bolus Day 1, 4, 8, and 11), and DXM (orally Day 1, 8, 15, and 22), every 4 weeks in 36 r/r MM patients. Twenty-two patients were treated using a standard dose escalation design (10 at the recommended dose [RD] cohort), and 14 additional patients were treated to expand the RD cohort. No dose-limiting toxicities (DLTs) occurred during dose escalation. The highest dose level evaluated (plitidepsin 5.0 mg/m² , BTZ 1.3 mg/m² , DXM 40.0 mg) was the RD for phase II studies. Results shown herein are focused on this RD. Two patients had DLTs (grade 3 diarrhea, and grade 3 nausea/vomiting refractory to antiemetic therapy). Grade ≥ 3 hematological toxicity (thrombocytopenia 46%, anemia 33%, and neutropenia 17%) was manageable and did not result in treatment discontinuation. Transient and manageable grade 3 ALT increase (26%) was the most common biochemical abnormality. At the RD cohort, overall response rate was 22.2% (95%CI, 6.4%-47.6%), including one stringent complete response, one very good partial response, and two partial responses in r/r patients to BTZ and/or lenalidomide. The clinical benefit rate was 77.8% (95%CI, 52.4-93.6%). No major pharmacokinetic drug-drug interaction was found. In conclusion, the triple combination of plitidepsin, BTZ, and DXM showed an acceptable safety profile and had moderate activity in adult patients with r/r MM.

Pomalidomide- and dexamethasone-based regimens in the treatment of refractory/relapsed multiple myeloma

Pomalidomide is a potent immunomodulatory agent that is currently a standard of care backbone for the treatment of multiple myeloma (MM) patients in the relapsed/refractory setting after exposure to lenalidomide and a proteasome inhibitor. The present review addresses current knowledge regarding the clinical use of pomalidomide in relapsed myeloma patients. Pomalidomide has direct myeloma cell tumoricidal effects by activating proteasomal degradation of Ikaros and Aiolos transcription factors and also indirect effects by modulation of immune responses, interaction with bone marrow stromal cells, and inhibition of angiogenesis. It is approved by regulatory authorities as doublet combination with dexamethasone but four more triplets are also approved for this setting. Many ongoing trials are evaluating the pomalidomide-dexamethasone backbone with newer anti-myeloma class agents or in quadruplet combinations. Pomalidomide-dexamethasone is currently one of the powerful tools available for use in the relapsed/refractory MM setting. Insights into the synergistic immunomodulatory effects of pomalidomide and other anti-myeloma agents and the mechanisms that overcome clonal resistance will potentially allow targeted use of triplet combinations at each relapse.

The role of E3 ubiquitin ligase in multiple myeloma: potential for cereblon E3 ligase modulators in the treatment of relapsed/refractory disease

INTRODUCTION

Insights into the mechanisms of protein homeostasis and proteasomal degradation have led to new strategies of redirecting the ubiquitin-proteasome system (UPS) to reduce or eliminate proteins or survival factors key to malignant pathobiology, multiple myeloma (MM) in particular. These strategies have enabled researchers to target proteins that were previously considered difficult to modulate by pharmacological means.

AREAS COVERED

This review provides a brief overview of UPS biology, particularly the role of the CRL4^CRBN E3 ubiquitin ligase complex, and summarizes current strategies for co-opting the UPS, including CELMoD compounds, SNIPERs, PROTACs, and degronimids. A detailed discussion is provided on lead CELMoD compounds iberdomide and mezigdomide, which are currently being evaluated in clinical trials in patients with MM.

EXPERT OPINION

Since a high proportion of patients develop drug resistance, it is vital to have novel therapeutic agents for treating relapsed patients with MM more effectively. It is encouraging that the expanding pathophysiological insight into cellular signaling pathways in MM increasingly translates into the development of novel therapeutic agents such as targeted protein degraders. This holds promise for improving outcomes in MM and beyond.

Population pharmacokinetic and exposure-response analyses of elotuzumab plus pomalidomide and dexamethasone for relapsed and refractory multiple myeloma

Purpose

Elotuzumab plus pomalidomide/dexamethasone (E-Pd) demonstrated efficacy and safety in relapsed and refractory multiple myeloma (RRMM). The clinical pharmacology of elotuzumab [± lenalidomide/dexamethasone (Ld)] was characterized previously. These analyses describe elotuzumab population pharmacokinetics (PPK), the effect of Pd, and assess elotuzumab exposure–response relationships for efficacy and safety in patients with RRMM.

Methods

A previously established PPK model was updated with E-Pd data from the phase 2 ELOQUENT-3 study (NCT02654132). The dataset included 8180 serum concentrations from 440 patients with RRMM from 5 clinical trials. Elotuzumab PK parameter estimates were used to generate individual daily time-varying average concentrations (daily C_avg) for multi-variable time-to-event exposure–response analyses of progression-free survival (PFS) and time to the first occurrence of grade 3 + adverse events (AEs) in RRMM.

Results

Elotuzumab PK were well-described by a two-compartment model with parallel linear and Michaelis–Menten elimination from the central compartment (V_max) and non-renewable target-mediated elimination from the peripheral compartment (K_int). Co-administration with Pd resulted in a 19% and 51% decrease in elotuzumab linear clearance and K_int, respectively, versus Ld; steady-state exposures were similar. V_max increased with increasing serum M-protein. Hazard ratios (95% confidence intervals) for daily C_avg were 0.9983 (0.9969–0.9997) and 0.9981 (0.9964–0.9998) for PFS and grade 3 + AEs, respectively.

Conclusions

The PPK model adequately described the data and was appropriate for determining exposures for exposure–response analyses. There were no clinically relevant differences in elotuzumab exposures between Pd and Ld backbones. In ELOQUENT-3, increasing elotuzumab daily C_avg prolonged PFS without increasing grade 3 + AEs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-021-04365-4.

Pathogenesis and treatment of multiple myeloma bone disease

Multiple myeloma (Plasma cell myeloma), a malignancy of the plasma cells, exhibits tumor expansion preferentially in the bone marrow and the development of bone-destructive lesions. Multiple myeloma is still an incurable disease with changes in the bone marrow microenvironment in favor of the survival and proliferation of multiple myeloma cells and bone destruction. In this review, we described the recent findings on the regulators involved in the development of myeloma bone diseases, and succinctly summarize currently available therapeutic options and the development of novel bone modifying agents for myeloma treatment.

Pomalidomide, bortezomib, and dexamethasone at first relapse in lenalidomide-pretreated myeloma: A subanalysis of OPTIMISMM by clinical characteristics

Objective

We evaluated the efficacy and safety of pomalidomide, bortezomib, and dexamethasone (PVd) vs bortezomib and dexamethasone (Vd) by age, renal function, and high‐risk cytogenetic abnormalities in lenalidomide‐pretreated patients with multiple myeloma at first relapse.

Methods

OPTIMISMM was a phase 3, multicenter, open‐label, randomized study (NCT01734928; N = 559). The primary endpoint was progression‐free survival (PFS).

Results

Overall, 226 patients had received one prior line of therapy. PVd significantly prolonged PFS vs Vd in patients aged ≤65 years (median, 22.0 vs 13.1 months; P = .0258) and >65 years (median, 17.6 vs 9.9 months; P = .0369). Median PFS in patients with renal impairment (RI; creatinine clearance <60 mL/min) was 15.1 months with PVd vs 9.5 months with Vd (hazard ratio [HR], 0.67 [95% CI, 0.34‐1.34]). In patients without RI, median PFS was 22.0 vs 13.1 months (HR, 0.45 [95% CI, 0.27‐0.76]). In patients with high‐risk cytogenetics, median PFS was 14.7 vs 9.9 months (HR, 0.39 [95% CI, 0.13‐1.17]). PVd significantly improved overall response rate vs Vd in all subgroups. The safety profile of PVd was consistent with previous reports.

Conclusions

These findings confirmed the benefits of PVd at first relapse, including in patients with poor prognostic factors.

Biological and Translational Considerations regarding the Recent Therapeutic Successes and Upcoming Challenges for Multiple Myeloma

Even though multiple myeloma (MM) is still considered incurable, the therapeutic management of this disease has undergone a major transformation over the last two decades, with several new classes of therapeutics and diverse options for their combined use in many different regimens that have contributed to major improvement in overall survival of patients. This review discusses key themes underlying the pharmacological and immune-based therapies that represent the cornerstones of this progress. A major part of the clinical progress achieved by these classes' therapeutics has depended on the targeting of molecular pathways with distinct or preferential roles for the biology of plasma cells-normal or malignant-and the ability of many of these agents to be incorporated into combination regimens that exhibit enhanced antimyeloma responses, without precipitating acceptable levels of toxicity. This review also discusses why these advances have not yet translated into curative outcomes and how these remaining barriers could be overcome.

The immunomodulatory drugs lenalidomide and pomalidomide enhance the potency of AMG 701 in multiple myeloma preclinical models

We investigated here the novel immunomodulation and anti-multiple myeloma (MM) function of T cells engaged by the bispecific T-cell engager molecule AMG 701, and further examined the impact of AMG 701 in combination with immunomodulatory drugs (IMiDs; lenalidomide and pomalidomide). AMG 701 potently induced T-cell-dependent cellular cytotoxicity (TDCC) against MM cells expressing B-cell maturation antigen, including autologous cells from patients with relapsed and refractory MM (RRMM) (half maximal effective concentration, <46.6 pM). Besides inducing T-cell proliferation and cytolytic activity, AMG 701 also promoted differentiation of patient T cells to central memory, effector memory, and stem cell-like memory (scm) phenotypes, more so in CD8 vs CD4 T subsets, resulting in increased CD8/CD4 ratios in 7-day ex vivo cocultures. IMiDs and AMG 701 synergistically induced TDCC against MM cell lines and autologous RRMM patient cells, even in the presence of immunosuppressive bone marrow stromal cells or osteoclasts. IMiDs further upregulated AMG 701-induced patient T-cell differentiation toward memory phenotypes, associated with increased CD8/CD4 ratios, increased Tscm, and decreased interleukin 10-positive T and T regulatory cells (CD25highFOXP3high), which may downregulate T effector cells. Importantly, the combination of AMG 701 with lenalidomide induced sustained inhibition of MM cell growth in SCID mice reconstituted with human T cells; tumor regrowth was eventually observed in cohorts treated with either agent alone (P < .001). These results strongly support AMG 701 clinical studies as monotherapy in patients with RRMM (NCT03287908) and the combination with IMiDs to improve patient outcomes in MM.

Impact of last lenalidomide dose, duration, and IMiD-free interval in patients with myeloma treated with pomalidomide/dexamethasone

To gain insights into the characteristics of clinical resistance to lenalidomide, we evaluated the outcomes of 147 consecutive patients with multiple myeloma (MM) homogeneously treated with immunomodulatory imide drugs (IMiDs) pomalidomide and dexamethasone (Pd) for relapsed and/or refractory MM (median, 3 prior lines of treatment). We focused our analysis on the effect of the lenalidomide dose at which resistance was developed, the duration of lenalidomide exposure, and lenalidomide-free interval. On intent to treat, 33% of patients achieved ≥partial remission (PR) with Pd. When Pd was given immediately after lenalidomide, ≥PR was 32% (vs 37% after bortezomib). The response rates were similar for patients that received 5 to 15 mg vs 25 mg of lenalidomide (38.5% vs 30.5%, P = .329). Response rates were higher for patients that had received at least 12 months of lenalidomide (44% vs 27%) and for those with ≥18 months from last lenalidomide dose to pomalidomide dose (65% vs 23%). Median progression-free survival (PFS) and overall survival (OS) were 5 and 12.1 months, respectively, which was similar for patients who received lenalidomide, bortezomib or other regimens just before Pd and similar for patients who were receiving different doses of lenalidomide. IMiD-free interval ≥18 months was associated with longer PFS (10.3 vs 3.9 months, P = .003) and OS (27.1 vs 9.3, P = .008) as well as duration of last lenalidomide therapy ≥12 months (PFS: 7.8 vs 3.2, P = .023; OS: 16.5 vs 7.9, P = .005) even after adjustment for the number of prior therapies, duration of disease, and last lenalidomide dose.

A novel phosphoramide compound, DCZ0847, displays in vitro and in vivo anti-myeloma activity, alone or in combination with bortezomib

Multiple myeloma (MM) is an incurable hematological malignancy, for which novel effective therapies are urgently needed. We synthesized a novel phosphoramide compound, DCZ0847, showing a potent anti-myeloma activity both in vitro and in vivo. DCZ0847 showed high cytotoxicity towards primary MM cells but had no effect on normal cells and was well tolerated in vivo. The anti-myeloma activity of DCZ0847 was associated with inhibition of cell proliferation; promotion of cell apoptosis via mitochondrial transmembrane potential collapse and caspase-mediated extrinsic or intrinsic apoptotic pathways; and the induction of G2/M phase arrest via downregulation of CDC25C, CDK1, and cyclin B1. In particular, DCZ0847 induced DNA damage and triggered a DNA-damage response by enhancing the levels of γ-H2A.X, phosphorylated (p)-ATM, p-ATR, p-Chk1, and p-Chk2. Additionally, DCZ0847 was able to overcome the bone marrow stromal cells-induced proliferation of MM cells and blocked JAK2/STAT3 signaling. Importantly, DCZ0847 acted synergistically with bortezomib, with the combination exerting greater cytotoxic effects in vitro and in vivo. Together, our results indicate that DCZ0847, alone or in combination with bortezomib, may represent a potential new therapy for patients with MM.

Pomalidomide, cyclophosphamide, and dexamethasone for elderly patients with relapsed and refractory multiple myeloma: A study of the Korean Multiple Myeloma Working Party (KMMWP-164 study)

Patients with transplant‐ineligible relapsed and refractory multiple myeloma (RRMM) have a short life expectancy, especially when they have failed both the proteasome inhibitor and immunomodulator therapies. This study aimed to assess the efficacy and safety of pomalidomide, cyclophosphamide, and dexamethasone (PCd) in elderly patients with RRMM. This phase 2 clinical trial recruited 55 elderly patients with RRMM. The patients underwent a 28‐day treatment cycle: pomalidomide (4 mg/day on days 1‐21, administered orally) and cyclophosphamide (400 mg/day on days 1, 8, and 15; administered orally) plus dexamethasone. The median (range) age of the patients was 73.3 (64‐86) years, and 8 (14.5%) patients who were ≥ 80 years old. Eight (14.5%) and 31 (56.4%) patients exhibited stage III (revised international staging system) and frail status (simplified frailty scale), respectively. The overall response rate (ORR) and clinical benefit rate (CBR) of PCd therapy were 58.2% and 72.7%, respectively. The median PFS and median overall survival (OS) were 6.90 months (95% CI, 4.7‐9.0) and 18.48 months (95% CI, 9.4‐27.6), respectively. The incidence rate of grade ≥ 3 non‐hematological toxicities was 70.8%. In particular, the incidence rate of primary infection was 45.4%, including 21.8% for pneumonia, 9.0% for sepsis, and 14.6% for febrile neutropenia. In conclusion, PCd is an effective regimen for elderly patients with RRMM who had failed both bortezomib and lenalidomide treatments, but in whom the treatment‐associated infection is the main cause of morbidity and mortality.

Mechanism of Action and Novel IMiD-Based Compounds and Combinations in Multiple Myeloma

Over the last 2 decades, thalidomide analogs have induced significant antimyeloma effects via immune-modulation, antiangiogenesis and antiproliferative effects. While the exact molecular mechanism of the targets or the mediators of thalidomide activity were not known, a seminal discovery of cereblon as a thalidomide-binding protein led to explaining the mechanistic basis of antimyeloma activity for this class of agents. Identification of the mechanisms of resistance for immunomodulatory agents (IMiDs), which will have significant clinical implications, remains poorly understood. Newer cereblon modulators with differential effects and improved increased efficacy in cell lines resistant to the current IMiDs are in development with encouraging preclinical data. In this review, we have summarized the mechanisms of action of IMiDs, clinical development, and potential mechanisms of resistance. We also describe novel IMiD-based combinations and the newer cereblon modulators as well.

Resistance to the Proteasome Inhibitors: Lessons from Multiple Myeloma and Mantle Cell Lymphoma

Since its introduction in the clinics in early 2000s, the proteasome inhibitor bortezomib (BTZ) significantly improved the prognosis of patients with multiple myeloma (MM) and mantle cell lymphoma (MCL), two of the most challenging B cell malignancies in western countries. However, relapses following BTZ therapy are frequent, while primary resistance to this agent remains a major limitation for further development of its therapeutic potential. In the present chapter, we recapitulate the molecular mechanisms associated with intrinsic and acquired resistance to BTZ learning from MM and MCL experience, including mutations of crucial genes and activation of prosurvival signalling pathways inherent to malignant B cells. We also outline the preclinical and clinical evaluations of some potential druggable targets associated to BTZ resistance, considering the most meaningful findings of the past 10 years. Although our understanding of BTZ resistance is far from being completed, recent discoveries are contributing to develop new approaches to treat relapsed MM and MCL patients.

Next-generation immunomodulatory drugs in multiple myeloma

Multiple myeloma (MM) is a hematological malignancy that mainly affects elderly patients, with the median age of 69 years at the time of diagnosis. Despite the recent increase in the number of drugs used in the antimyeloma therapy, the disease remains incurable, with remissions and subsequent relapses. Immunomodulatory drugs (IMIDs), known to have multiple mechanisms of actions, including direct anti-MM activity and immune-stimulatory properties, are currently the backbone in multidrug regimens. New generation IMIDs are recommended nowoby ESMO – lenalidomide is included in frontline therapy, while pomalidomide is accepted from the third line. Clinical trials proved lack of apparent cross-resistance between immunomodulatory agents, confirmed their high efficacy and acceptable safety profile in individuals with relapsed multiple myeloma (RRMM) refractory to proteasome inhibitors and lenalidomide, even with adverse cytogenetic abnormalities. Also, triplet pomalidomide-based combinations with bortezomib, carfilzomib, cyclophosphamide, daratumumab or elotuzumab were proved to be effective and safe in this group of patients. The most common adverse events of the new generation IMIDs are the following: hematological toxicity (neutropenia, thrombocytopenia, anemia), fatigue and, while administered with dexamethasone, infections. However, peripheral neuropathy, significantly limiting the use of first generation IMID - thalidomide, is much less frequently observed. Due to the increased risk of venous thromboembolism, thromboprophylaxis should be implemented in the whole course of IMID therapy. Data from real-life settings demonstrate that new generation IMIDs are a cost-effective treatment option in relapsed/ refractory myeloma. Currently, one drug program with the new IMIDs is available in Poland.

[PET/CT with 18F-fluorodeoxyglucose and 11C-methionine after autologous stem cell transplantation in multiple myeloma patients]

AIM

to compare the results of tumor visualization when using 18F-FDG and 11C-methionine PET/CT after auto-HSCT in MM patients.

MATERIALS AND METHODS

A prospective study included 27 MM patients subjected to 18F-FDG and 11C-methionine PET/CT on day 100 after auto-HSCT. Obtained images were visually and semi - quantitatively analyzed. Focal areas of increased uptake for every radiopharmaceutical agent (hypermetabolic foci) not associated with its physiological distribution were registered. Maximum Standardized Uptake Values (SUVmax) in pathological foci were automatically calculated for every radiopharmaceutical agent separately. PET/CT findings were compared to antitumor response achieved after auto-HSCT according to International MM Working Group criteria.

RESULTS

After auto-HSCT, the majority of patients (16/60%) achieved a complete response. Abnormal 18F-FDG uptake was registered in 37% (n=10) of patients, negative PET findings were obtained in 63% (n=17) of patients. 11C-methionine PET/CT revealed hypermetabolic foci in 67% (n=18) of patients, and there was no 11C-methionine uptake in 33% (n=9). Pathological foci of radiopharmaceutical agent uptake were 1.8 times more frequently revealed using PET/CT with 11C-methionine (p.

Weekly carfilzomib, lenalidomide, and dexamethasone in relapsed or refractory multiple myeloma: A phase 1b study

Twice-weekly carfilzomib (27 mg/m2 ) with lenalidomide-dexamethasone (KRd) is a standard-of-care in relapsed or refractory multiple myeloma (RRMM). This phase 1b study evaluated KRd with once-weekly carfilzomib in RRMM. Patients received carfilzomib (30-minute infusion; 56 or 70mg/m2 ) on days 1, 8, and 15; lenalidomide 25 mg on days 1-21; and dexamethasone 40 mg on days 1, 8, 15, and 22 (day 22 omitted for cycles 9+) of 28-day cycles. Primary objective was safety/tolerability; efficacy was a secondary objective. Fifty-six RRMM patients enrolled: 22 during dose evaluation (56-mg/m2 , n = 10; 70-mg/m2 , n = 12) and 34 during dose expansion (all initiated dosing at 70 mg/m2 ). After 2 fatal adverse events (AEs) during 70-mg/m2 dose expansion, dosage reduction to 56 mg/m2 was permitted. Results are presented for carfilzomib 56-mg/m2 (n = 10) and 70-mg/m2 groups (dose evaluation/expansion; n = 46). Median carfilzomib dose was 53.2 mg/m2 (56-mg/m2 group) and 62.4 mg/m2 (70-mg/m2 group). Grade ≥3 AE rates were 70.0% (56 mg/m2 ) and 69.6% (70 mg/m2 ). Overall response rates were 90.0% (56 mg/m2 ) and 89.1% (70 mg/m2 ); ≥very good partial response rates were 50.0% (56 mg/m2 ) and 73.9% (70 mg/m2 ). Once-weekly KRd was active with acceptable toxicity in RRMM, supporting further evaluation of this regimen.

Insights on Multiple Myeloma Treatment Strategies

The introduction of new agents and management strategies over the past decade has resulted in a major step change in treatment outcomes with deepening responses and increased survival for patients with multiple myeloma. In daily clinical practice, healthcare professionals are now faced with challenges including, optimal treatment sequencing and changing treatment goals. In light of this, a group of experts met to discuss diagnostic and treatment guidelines, examine current clinical practice, and consider how new clinical trial data may be integrated into the management of multiple myeloma in the future.

Rafoxanide, an organohalogen drug, triggers apoptosis and cell cycle arrest in multiple myeloma by enhancing DNA damage responses and suppressing the p38 MAPK pathway

Rafoxanide is used in veterinary medicine for the treatment of fascioliasis. We previously repositioned the drug as the inhibitor of B-Raf V600E, but its anti-tumor effect in human cancer has never been reported. In this study, we investigated the effects of rafoxanide in multiple myeloma (MM) in vitro and in vivo. We found that rafoxanide inhibited cell proliferation and overcame the protective effect of the bone marrow (BM) microenvironment on MM cells. Rafoxanide induced cell apoptosis by reducing mitochondrial membrane potential (MMP) and regulating the caspase pathway, while having no apparent toxic effect on normal cells. Rafoxanide also inhibited DNA synthesis and caused cell cycle arrest by regulating the cdc25A-degradation pathway. In addition, rafoxanide enhanced the DNA damage response by up-regulating the expression of γ-H2AX, and suppressed activation of the p38 MAPK pathway by down-regulating p38 MAPK phosphorylation and Stat1 phosphorylation. Rafoxanide treatment inhibited tumor growth, with no significant side effects, in an MM mouse xenograft model. Combination of rafoxanide with bortezomib or lenalidomide significantly induced synergistic cytotoxicity in MM cells. Finally, rafoxanide had anti-proliferation effect on both wild type and B-Raf V600E mutated MM cells. And the weaker anti-MM activity of rafoxanide than vemurafenib may indicate other potential mechanisms besides targeting B-Raf V600E mutation. Collectively, our results provide a rationale for use of this drug in MM treatment.

Efficacy of lenalidomide as salvage therapy for patients with AL amyloidosis

We retrospectively evaluated 55 consecutive patients who received at least one dose of lenalidomide for relapsed/refractory AL amyloidosis. Their median age was 63 years; 72% had heart and 75% kidney involvement and 13% were on dialysis; while 20%, 46% and 34% had Mayo stage -1, -2 and -3 disease, respectively. Median time from start of primary therapy to lenalidomide was 15 months (range 2-100) and median number of prior therapies was 1 (range 1-4); 73% of the patients had prior bortezomib and 42% were bortezomib-refractory. On intent to treat, haematologic response rate was 51% (5.5% CRs, 20% VGPRs) and was 56% versus 40% for patients with and without prior bortezomib and 47% versus 62.5% for bortezomib refractory versus non-refractory patients (p = .351). Organ response was achieved by 16% of evaluable patients (22% renal, 7% liver and 3% cardiac); however, 10 (21%) patients progressed to dialysis. Median survival post lenalidomide was 25 months. Bortezomib-refractory patients had worse outcome (median survival of 10.5 versus 25 months for bortezomib-sensitive patients versus not reached for bortezomib-naive patients, p = .011). Median lenalidomide dose was 10 mg and no patient received the 25 mg dose; however, in 60% a dose reduction was required. Median duration of lenalidomide therapy was 7.2 months and 46% discontinued lenalidomide before completion of planned therapy, mainly due to toxicity (26%) or disease progression/no response (13%). We conclude that although lenalidomide is a major salvage option for patients with relapsed/refractory AL amyloidosis, its toxicity in patients with AL amyloidosis is significant and doses should be adjusted for optimal tolerability.

The proteasome and proteasome inhibitors in multiple myeloma

Proteasome inhibitors are one of the most important classes of agents to have emerged for the treatment of multiple myeloma in the past two decades, and now form one of the backbones of treatment. Three agents in this class have been approved by the United States Food and Drug Administration-the first-in-class compound bortezomib, the second-generation agent carfilzomib, and the first oral proteasome inhibitor, ixazomib. The success of this class of agents is due to the exquisite sensitivity of myeloma cells to the inhibition of the 26S proteasome, which plays a critical role in the pathogenesis and proliferation of the disease. Proteasome inhibition results in multiple downstream effects, including the inhibition of NF-κB signaling, the accumulation of misfolded and unfolded proteins, resulting in endoplasmic reticulum stress and leading to the unfolded protein response, the downregulation of growth factor receptors, suppression of adhesion molecule expression, and inhibition of angiogenesis; resistance to proteasome inhibition may arise through cellular responses mediating these downstream effects. These multiple biologic consequences of proteasome inhibition result in synergistic or additive activity with other chemotherapeutic and targeted agents for myeloma, and proteasome inhibitor-based combination regimens have become established as a cornerstone of therapy throughout the myeloma treatment algorithm, incorporating agents from the other key classes of antimyeloma agents, including the immunomodulatory drugs, monoclonal antibodies, and histone deacetylase inhibitors. This review gives an overview of the critical role of the proteasome in myeloma and the characteristics of the different proteasome inhibitors and provides a comprehensive summary of key clinical efficacy and safety data with the currently approved proteasome inhibitors.

DNMTi/HDACi combined epigenetic targeted treatment induces reprogramming of myeloma cells in the direction of normal plasma cells

Background

Multiple myeloma (MM) is the second most common hematologic malignancy. Aberrant epigenetic modifications have been reported in MM and could be promising therapeutic targets. As response rates are overall limited but deep responses occur, it is important to identify those patients who could indeed benefit from epigenetic-targeted therapy.

Methods

Since HDACi and DNMTi combination have potential therapeutic value in MM, we aimed to build a GEP-based score that could be useful to design future epigenetic-targeted combination trials. In addition, we investigated the changes in GEP upon HDACi/DNMTi treatment.

Results

We report a new gene expression-based score to predict MM cell sensitivity to the combination of DNMTi/HDACi. A high Combo score in MM patients identified a group with a worse overall survival but a higher sensitivity of their MM cells to DNMTi/HDACi therapy compared to a low Combo score. In addition, treatment with DNMTi/HDACi downregulated IRF4 and MYC expression and appeared to induce a mature BMPC plasma cell gene expression profile in myeloma cell lines.

Conclusion

In conclusion, we developed a score for the prediction of primary MM cell sensitivity to DNMTi/HDACi and found that this combination could be beneficial in high-risk patients by targeting proliferation and inducing maturation.

Triplet vs. doublet drug regimens for managing multiple myeloma

INTRODUCTION

Multiple Myeloma (MM) is a complex and heterogeneous plasma cell disorder. Sub-clones present before therapy and clonal evolution during therapy make this disease more resistant and finally refractory. These findings make us aware of the difficulty to target MM with few agents. Multi-drugs therapies allow us to target more pathways and more sub-clones both at diagnosis and in advanced disease.

AREAS COVERED

In this review, the authors focus on the effectiveness and tolerability of three drug regimens (triplet) in comparison with two drug regimens (doublet) and discuss their implications in the present and future of MM therapy.

EXPERT OPINION

It has been demonstrated that triplet regimens are better than doublet in terms of response rate and PFS in newly diagnosed, relapsed-refractory MM and in most patient subgroups. Whether this translates into OS improvement needs further demonstration. However, achievement of MRD negativity in most newly diagnosed and, firstly, in a consistent proportion of relapsed-refractory MM patients is very encouraging in this respect. However, not all patients are able to tolerate all triplet combinations; therefore, the choice should be based on patient characteristics, besides disease features. Finally, cost of triplets may be an important limitation in some countries.