Carfilzomib in multiple myeloma patients with renal impairment: pharmacokinetics and safety

Serum Free Light Chain Kinetics Is Predictive of Renal Response in Myeloma Patients With Renal Impairment-An ALLG Trial of Carfilzomib-Dexamethasone Therapy in Frontline and Relapse

BACKGROUND AND PURPOSE

Renal impairment (RI) confers adverse prognosis in myeloma; its reversal and avoidance of dialysis are crucial. We investigated whether serum free light chain (SFLC) measurements can predict renal outcome, to enable change in therapy to optimize prognosis and avoid dialysis.

PATIENTS AND METHODS

We investigated 36 myeloma patients (17 newly diagnosed [ND]; 19 relapsed refractory [RR]; with median of 5 prior lines) with eGFR 15-40 ml/min treated with carfilzomib (Cfz)-dexamethasone to determine whether SFLC kinetics can predict renal outcomes, and assess efficacy and tolerability.

RESULTS

The change in involved SFLC at Cycle 2 Day 1 was significantly correlated with renal function; for every one log10 reduction in involved SFLC, eGFR increased by 9.0-15.0 mL/min at cycles 2-4, with SFLC reduction of 54%-78%. At a median follow-up of 30.6 months, renal outcomes were favorable-CRrenal 25%, MRrenal 36%. Disease responses (ND 100%, RR 75%), progression-free survival (ND 32.2 months, RR 11.1 months) and overall survival (ND not reached, RR 42.0 months) were comparable to patients without RI. There was significant toxicity, including Cfz-related cardiac impairment of 20% within a cohort with high co-morbidity, and a high incidence of infections.

CONCLUSION

We propose that one log10 reduction in involved SFLC at Cycle 2 Day 1 is an appropriate target for reducing the risk of dialysis in myeloma patients with RI; below this threshold patients may benefit from a change in therapy. While Cfz-dexamethasone achieved favorable renal and disease outcomes, toxicity can be significant in this vulnerable cohort.

Risk factors associated with overall survival in patients with multiple myeloma following carfilzomib treatment: A retrospective study from a large claims database in Japan

BACKGROUND

Carfilzomib is a selective proteasome inhibitor approved for treating relapsed or refractory multiple myeloma (RRMM). Carfilzomib improves overall survival (OS) and progression-free survival (PFS); however, treatment with carfilzomib results in a higher incidence of cardiovascular and renal toxicity. More than 70% of patients with RRMM in clinical practice do not meet the eligibility criteria for randomized clinical trials (RCT). OS and PFS are negatively influenced by complications, concomitant medications and prior treatments. Therefore, we assessed the risk factors influencing the OS and time to next treatment (TTNT) in the real world. TTNT has emerged as a relevant alternative clinical endpoint to PFS.

METHODS

A retrospective analysis of a large claims database prepared during the post-marketing stages in Japan was performed. The patients treated with carfilzomib for the first time were identified. Multivariable Cox proportional hazards regression analysis was performed to evaluate the risk factors influencing OS and TTNT following carfilzomib treatment.

RESULTS

A total of 732 patients with RRMM who received carfilzomib-containing chemotherapy between April 2014 and September 2021 were identified. Multivariable Cox regression analysis for OS and TTNT showed a significantly higher hazard ratio (HR) of 1.48 (95% confidence interval [Cl]: 1.10-2.00; p = 0.010) and 1.38 (95% Cl: 1.15-1.65; p < 0.001), respectively, for patients with renal impairment compared to those without renal impairment. Multivariable Cox regression analysis for OS and TTNT showed a significantly higher HR of 1.80 (95% Cl: 1.27-2.55; p = 0.0010) and 1.38 (95% Cl: 1.14-1.66; p < 0.001), respectively, for patients with prior lenalidomide treatment compared to those without prior lenalidomide treatment.

CONCLUSION

Complication of renal impairment and prior lenalidomide treatment could be risk factors influencing OS and TTNT during carfilzomib treatment.

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.

Proteomic Alteration in the Progression of Multiple Myeloma: A Comprehensive Review

Multiple myeloma (MM) is an incurable hematologic malignancy. Most MM patients are diagnosed at a late stage because the early symptoms of the disease can be uncertain and nonspecific, often resembling other, more common conditions. Additionally, MM patients are commonly associated with rapid relapse and an inevitable refractory phase. MM is characterized by the abnormal proliferation of monoclonal plasma cells in the bone marrow. During the progression of MM, massive genomic alterations occur that target multiple signaling pathways and are accompanied by a multistep process involving differentiation, proliferation, and invasion. Moreover, the transformation of healthy plasma cell biology into genetically heterogeneous MM clones is driven by a variety of post-translational protein modifications (PTMs), which has complicated the discovery of effective treatments. PTMs have been identified as the most promising candidates for biomarker detection, and further research has been recommended to develop promising surrogate markers. Proteomics research has begun in MM, and a comprehensive literature review is available. However, proteomics applications in MM have yet to make significant progress. Exploration of proteomic alterations in MM is worthwhile to improve understanding of the pathophysiology of MM and to search for new treatment targets. Proteomics studies using mass spectrometry (MS) in conjunction with robust bioinformatics tools are an excellent way to learn more about protein changes and modifications during disease progression MM. This article addresses in depth the proteomic changes associated with MM disease transformation.

Management of multiple myeloma-related renal impairment: recommendations from the International Myeloma Working Group

Here, the International Myeloma Working Group (IMWG) updates its clinical practice recommendations for the management of multiple myeloma-related renal impairment on the basis of data published until Dec 31, 2022. All patients with multiple myeloma and renal impairment should have serum creatinine, estimated glomerular filtration rate, and free light chains (FLCs) measurements together with 24-h urine total protein, electrophoresis, and immunofixation. If non-selective proteinuria (mainly albuminuria) or involved serum FLCs value less than 500 mg/L is detected, then a renal biopsy is needed. The IMWG criteria for the definition of renal response should be used. Supportive care and high-dose dexamethasone are required for all patients with myeloma-induced renal impairment. Mechanical approaches do not increase overall survival. Bortezomib-based regimens are the cornerstone of the management of patients with multiple myeloma and renal impairment at diagnosis. New quadruplet and triplet combinations, including proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies, improve renal and survival outcomes in both newly diagnosed patients and those with relapsed or refractory disease. Conjugated antibodies, chimeric antigen receptor T-cells, and T-cell engagers are well tolerated and effective in patients with moderate renal impairment.

Thymoquinone Ameliorates Carfilzomib-Induced Renal Impairment by Modulating Oxidative Stress Markers, Inflammatory/Apoptotic Mediators, and Augmenting Nrf2 in Rats

Chemotherapy-induced kidney damage is an emerging problem that restricts cancer treatment effectiveness. The proteasome inhibitor carfilzomib (CFZ) is primarily used to treat multiple myeloma and has been associated with severe renal injury in humans. CFZ-induced nephrotoxicity remains an unmet medical need, and there is an urgent need to find and develop a nephroprotective and antioxidant therapy for this condition. Thymoquinone (TQ) is a bioactive compound that has been isolated from Nigella sativa seeds. It has a wide range of pharmacological properties. Therefore, this experimental design aimed to study the effectiveness of TQ against CFZ-induced renal toxicity in rats. The first group of rats was a normal control (CNT); the second group received CFZ (4 mg/kg b.w.); the third and fourth groups received TQ (10 and 20 mg/kg b.w.) 2 h before receiving CFZ; the fifth group received only TQ (20 mg/kg b.w.). This experiment was conducted for 16 days, and at the end of the experiment, blood samples and kidney tissue were collected for biochemical assays. The results indicated that administration of CFZ significantly enhanced serum marker levels such as BUN, creatinine, and uric acid in the CFZ group. Similarly, it was also noticed that CFZ administration induced oxidative stress by reducing antioxidants (GSH) and antioxidant enzymes (CAT and SOD) and increasing lipid peroxidation. CFZ treatment also enhanced the expression of IL-1β, IL-6, and TNF-α production. Moreover, CFZ increased caspase-3 concentrations and reduced Nrf2 expression in the CFZ-administered group. However, treatment with 10 and 20 mg/kg TQ significantly decreased serum markers and increased antioxidant enzymes. TQ treatment considerably reduced IL-1β, IL-6, TNF-α, and caspase-3 concentrations. Overall, this biochemical estimation was also supported by histopathological outcomes. This study revealed that TQ administration significantly mitigated the negative effects of CFZ treatment on Nrf2 expression. Thus, it indicates that TQ may have utility as a potential drug to prevent CFZ-induced nephrotoxicity in the future.

Partnering With All Patients: Ensuring Shared Decision Making and Evidence-Based Management for Underrepresented Groups With Multiple Myeloma

Several landmark therapeutic advances in multiple myeloma (MM) have led to an unprecedented number of options available to patients and their physicians as shared decision making is attempted. A myriad of factors need to be considered to ensure that patient-, disease-, and treatment-related factors are addressed to arrive at the most appropriate choice for patients at that time in their journey with myeloma. Some of these factors have traditionally remained underaddressed but have a clear association with patient outcomes, leading to underrepresented groups of patients with MM, including the elderly patients, racial-ethnic minorities, and those with specific advanced comorbidities, for example, renal insufficiency. Some of these factors may not be modifiable, but data suggest that they may give rise to implicit or explicit bias and affect treatment decisions. A growing body of literature is bringing these factors to light. However, their incorporation in day-to-day decision making for patients needs to be universal. It is imperative that prospective data are generated for all these and other underrepresented groups such that evidence-based medicine is applicable universally to all patients with MM, irrespective of clinical and sociodemographic factors.

Multiple myeloma with acute light chain cast nephropathy

Light chain cast nephropathy (LCCN) is a leading cause of acute kidney injury (AKI) in patients with multiple myeloma (MM) and is now defined as a myeloma defining event. While the long-term prognosis has improved with novel agents, short-term mortality remains significantly higher in patients with LCCN especially if the renal failure is not reversed. Recovery of renal function requires a rapid and significant reduction of the involved serum free light chain. Therefore, proper treatment of these patients is of the utmost importance. In this paper, we provide an algorithm for treatment of MM patients who present with biopsy-proven LCCN or in those where other causes of AKI have been ruled out. The algorithm is based on data from randomized trial whenever possible. When trial data is not available, our recommendations is based on non-randomized data and expert opinions on best practices. We recommend that all patients should enroll in a clinical trial if available prior to resorting to the treatment algorithm we outlined.

Monoclonal gammopathy of renal significance: Multidisciplinary approach to diagnosis and treatment

Monoclonal gammopathy of renal significance (MGRS) is a hemato-nephrological term referring to a heterogeneous group of kidney disorders characterized by direct or indirect kidney injury caused by a monoclonal immunoglobulin (MIg) produced by a B cell or plasma cell clone that does not meet current hematologic criteria for therapy. MGRS-associated kidney diseases are diverse and can result in the development of end stage kidney disease (ESKD). The diagnosis is typically made by nephrologists through a kidney biopsy. Many distinct pathologies have been identified and they are classified based on the site or composition of the deposited Mig, or according to histological and ultrastructural findings. Therapy is directed towards the identified underlying clonal population and treatment decisions should be coordinated between hematologists and nephrologists in a multidisciplinary fashion, depend on the type of MGRS, the degree of kidney function impairment and the risk of progression to ESKD.

Severe pulmonary toxicity related to carfilzomib use: a rare but serious side effect

Carfilzomib is a selective proteosome inhibitor that is commonly used in the treatment of relapsed or refractory multiple myeloma. Carfilzomib has been commonly associated with respiratory side effects. It can rarely also cause fatal pulmonary toxicity. We present a case of a man in his 50s with plasma cell leukaemia who was initiated on treatment with carfilzomib and dexamethasone. He developed severe pneumonitis requiring oxygen via a high-flow nasal cannula. After an extensive workup, a temporal relationship between the carfilzomib use and exacerbation of the pulmonary symptoms was found. Carfilzomib was permanently discontinued, and the patient was started promptly on methyl prednisolone with complete resolution of his symptoms. Due to the associated risk of mortality if not detected early, we wish to highlight this rare but serious pulmonary toxicity associated with carfilzomib that was managed with high-dose glucocorticoids.

mRNA-miRNA bipartite networks reconstruction in different tissues of bladder cancer based on gene co-expression network analysis

Bladder cancer (BC) is one of the most important cancers worldwide, and if it is diagnosed early, its progression in humans can be prevented and long-term survival will be achieved accordingly. This study aimed to identify novel micro-RNA (miRNA) and gene-based biomarkers for diagnosing BC. The microarray dataset of BC tissues (GSE13507) listed in the GEO database was analyzed for this purpose. The gene expression data from three BC tissues including 165 primary bladder cancer (PBC), 58 normal looking-bladder mucosae surrounding cancer (NBMSC), and 23 recurrent non-muscle invasive tumor tissues (RNIT) were used to reconstruct gene co-expression networks. After preprocessing and normalization, deferentially expressed genes (DEGs) were obtained and used to construct the weighted gene co-expression network (WGCNA). Gene co-expression modules and low-preserved modules were extracted among BC tissues using network clustering. Next, the experimentally validated mRNA-miRNA interaction information were used to reconstruct three mRNA-miRNA bipartite networks. Reactome pathway database and Gene ontology (GO) was subsequently performed for the extracted genes of three bipartite networks and miRNAs, respectively. To further analyze the data, ten hub miRNAs (miRNAs with the highest degree) were selected in each bipartite network to reconstruct three bipartite subnetworks. Finally, the obtained biomarkers were comprehensively investigated and discussed in authentic studies. The obtained results from our study indicated a group of genes including PPARD, CST4, CSNK1E, PTPN14, ETV6, and ADRM1 as well as novel miRNAs (e.g., miR-16-5p, miR-335-5p, miR-124-3p, and let-7b-5p) which might be potentially associated with BC and could be a potential biomarker. Afterward, three drug-gene interaction networks were reconstructed to explore candidate drugs for the treatment of BC. The hub miRNAs in the mRNA-miRNA bipartite network played a fundamental role in BC progression; however, these findings need further investigation.

Advances in the Treatment of Relapsed and Refractory Multiple Myeloma in Patients with Renal Insufficiency: Novel Agents, Immunotherapies and Beyond

BACKGROUND

Renal insufficiency is one of the most frequent complications in multiple myeloma. The incidence of renal insufficiency in patients with multiple myeloma ranges from 20% to 50%. Renal impairment in patients with multiple myeloma results primarily from the toxic effects of monoclonal light chains on the kidneys. Dehydration, hypercalcemia, hyperuricemia, the application of nephrotoxic NSARs, antibiotics, contrast agents, etc., all play a major role in the deterioration of renal function in patients with multiple myeloma. The diagnosis and treatment of these patients use an interdisciplinary approach in consultation with hematologist-oncologists, radiologists, nephrologists and intensive care specialists. Using new drugs in the treatment of patients with refractory/relapsed multiple myeloma and renal insufficiency markedly improves progression-free survival and overall survival in these patients.

CONCLUSIONS

New drugs have helped to widen the treatment options available for patients with renal impairment and refractory/relapsed multiple myeloma, since dose adjustments are unnecessary with carfilzomib as well as with panobinostat, elotuzumab, pomalidomide or daratumumab in patients with renal impairment. Several new substances for the treatment of refractory/relapsed multiple myeloma have been approved in the meantime, including belantamab mafodotin, selinexor, melflufen, venetoclax, CAR T-cell therapy and checkpoint inhibitors. Ongoing studies are investigating their administration in patients with renal impairment.

A pilot study of 3D tissue-engineered bone marrow culture as a tool to predict patient response to therapy in multiple myeloma

Cancer patients undergo detrimental toxicities and ineffective treatments especially in the relapsed setting, due to failed treatment attempts. The development of a tool that predicts the clinical response of individual patients to therapy is greatly desired. We have developed a novel patient-derived 3D tissue engineered bone marrow (3DTEBM) technology that closely recapitulate the pathophysiological conditions in the bone marrow and allows ex vivo proliferation of tumor cells of hematologic malignancies. In this study, we used the 3DTEBM to predict the clinical response of individual multiple myeloma (MM) patients to different therapeutic regimens. We found that while no correlation was observed between in vitro efficacy in classic 2D culture systems of drugs used for MM with their clinical efficacious concentration, the efficacious concentration in the 3DTEBM were directly correlated. Furthermore, the 3DTEBM model retrospectively predicted the clinical response to different treatment regimens in 89% of the MM patient cohort. These results demonstrated that the 3DTEBM is a feasible platform which can predict MM clinical responses with high accuracy and within a clinically actionable time frame. Utilization of this technology to predict drug efficacy and the likelihood of treatment failure could significantly improve patient care and treatment in many ways, particularly in the relapsed and refractory setting. Future studies are needed to validate the 3DTEBM model as a tool for predicting clinical efficacy.

Carfilzomib, bendamustine, and dexamethasone in patients with advanced multiple myeloma: The EMN09 phase 1/2 study of the European Myeloma Network

BACKGROUND

Combined therapy with carfilzomib, bendamustine, and dexamethasone was evaluated in this multicenter phase 1/2 trial conducted within the European Myeloma Network (EMN09 trial).

METHODS

Sixty-three patients with relapsed/refractory multiple myeloma who had received ≥2 lines of prior therapy were included. The phase 1 portion of the study determined the maximum tolerated dose of carfilzomib with bendamustine set at 70 mg/m² on days 1 and 8. After 8 cycles, responding patients received maintenance therapy with carfilzomib and dexamethasone until progression.

RESULTS

On the basis of the phase 1 results, the recommended phase 2 dose for carfilzomib was 27 mg/m² twice weekly in weeks 1, 2, and 3. Fifty-two percent of patients achieved a partial response or better, and 32% reached a very good partial response or better. The clinical benefit rate was 93%. After a median follow-up of 21.9 months, the median progression-free survival was 11.6 months, and the median overall survival was 30.4 months. The reported grade ≥3 hematologic adverse events (AEs) were lymphopenia (29%), neutropenia (25%), and thrombocytopenia (22%). The main nonhematologic grade ≥3 AEs were pneumonia, thromboembolic events (10%), cardiac AEs (8%), and hypertension (2%).

CONCLUSIONS

In heavily pretreated patients who have relapsed/refractory multiple myeloma, combined carfilzomib, bendamustine, and dexamethasone is an effective treatment option administered in the outpatient setting. Infection prophylaxis and attention to patients with cardiovascular predisposition are required.

Renal failure among multiple myeloma patients utilizing carfilzomib and associated factors in the "real world"

Carfilzomib, a next-generation proteasome inhibitor, improves outcomes in patients with multiple myeloma (MM); however, a proportion of those treated develop renal failure due to adverse event, comorbidity, or myeloma progression. The rate of renal failure and associated risk factors remains unknown in real-world populations. Adults with relapsed/refractory MM who received carfilzomib between the years 2013 and 2016 were identified in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases. Renal failure was defined using the corresponding International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) diagnostic codes and procedure codes for dialysis. Patients with a pre-existing diagnosis of renal failure were excluded to distinguish an adverse event from comorbidity. Multivariate cox regression analysis was performed to identify the variables independently associated with the development of renal failure among MM patients utilizing carfilzomib. A total of 1950 patients were included in the analysis. Renal failure developed in 22% of patients during the study period. The median time to development of renal failure from first carfilzomib administration was 1.6 months (range < 0.1-23.3). Increasing age (adjusted hazard ratio [aHR] 1.01 per year, p = 0.018), pre-existing heart failure (aHR 1.50, p = 0.005), and pre-existing chronic kidney disease (aHR 2.00, p < 0.001) were associated with a higher risk of developing renal failure. Renal failure occurred in up to 22% of patients on carfilzomib therapy. The exact cause and mechanism of renal failure cannot be determined from our study and may be multifactorial. Future studies are needed to further understand the cause of renal failure among patients on carfilzomib and devise strategies to mitigate the risk.

Incidence and Management of Carfilzomib-induced Cardiovascular Toxicity; A Systematic Review and Meta-analysis

BACKGROUND

The ASPIRE and ENDEAVOUR trials have shown cardiovascular adverse effects in patients treated with carfilzomib-based regimens. Therefore, we conducted this meta-analysis of published clinical trials to identify the cumulative incidence and risk of cardiovascular adverse effects due to carfilzomib.

METHODS

A systematic search of PubMed, Embase, Web of Science, and Cochrane library was performed, and we identified 45 prospective trials of carfilzomib with data on 5583 patients. Among all patients being treated with carfilzomib (N=5,583), 8.9% sustained all grade cardiotoxicity, while 4.4% sustained high-grade cardiotoxicity. All-grade hypertension was present in 13.2%, while the incidence of high-grade hypertension was 5.3%.

RESULT

The observed incidences of all-grade heart failure, edema, and ischemia were 5.1%, 20.7%, and 4.6% respectively. Likewise, for high-grade heart failure and edema observed incidence was 3.2%, and 2.7% respectively. There was no difference in the event rate of all and high-grade cardiotoxicity between newly diagnosed multiple myeloma and relapsed/refractory (p-value 0.42 and 0.86 respectively). Likewise, we did not observe any difference in the event rate of all and high-grade cardiotoxicity when carfilzomib was used as a single agent versus when used in combination therapy with other agents (p-value 0.43 and 0.73 respectively).

CONCLUSION

Carfilzomib is associated with a significant risk of cardiovascular toxicity and hypertension. With the increasing utilization of carfilzomib, it is critical for primary care physicians, oncologists and cardiologists to be aware of the risk of cardiotoxicity associated with the use of carfilzomib to recognize and treat baseline cardiovascular risk factors in such patients.

Carfilzomib-associated renal toxicity is common and unpredictable: a comprehensive analysis of 114 multiple myeloma patients

Carfilzomib (CFZ) is a non-reversible proteasome inhibitor approved for the treatment of patients with relapsed and refractory myeloma (RRMM). Its use has been associated with cardiovascular toxicity but although recently a signal of clinically significant renal complications has also been identified, it is less extensively investigated. We analyzed data of 114 consecutive patients with RRMM who received CFZ-based regimens. Renal complications not related to MM progression were observed in 19 (17%) patients; thrombotic microangiopathy (TMA) was seen in 6 (5%) patients, albuminuria >1 gr/day in 7 patients (6%) and at least grade 3 acute kidney injury (AKI) which could not be otherwise explained in 6 patients (5%). A total of 15 patients discontinued CFZ and dosing was reinitiated at a lower level in one patient with AKI. Albuminuria was associated with focal segmental glomerulosclerosis in the renal biopsy (performed in a total of 6 patients). Renal complications during CFZ therapy are common, occur mostly early and are unpredictable. A potential effect of CFZ on the renal endothelium could be implicated in the pathogenesis of these complications and may also share common pathophysiology with cardiovascular effects of CFZ.

The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges

Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.

Treatment of relapsed multiple myeloma: Evidence-based recommendations

The practice of choosing the next best therapy for patients with relapsed and/or refractory multiple myeloma (RRMM) is becoming increasingly complex. There is no clear consensus regarding the best treatment sequence for RRMM. With the approval of novel proteasome inhibitors (ixazomib and carfilzomib), immunomodulatory agents (pomalidomide), monoclonal antibodies (daratumumab and elotuzumab), and other targeted therapies, multiple combination regimens utilizing these agents are being studied with the goal of enhancing disease control, prolonging progression-free survival, and improving overall survival. We, herein, describe a review of FDA-approved regimens for RRMM patients and offer a paradigm in selecting subsequent treatment regimens, focusing on patient specific morbidity, treatment toxicity, and disease-specific characteristics.

Pharmacodynamics and pharmacokinetics of proteasome inhibitors for the treatment of multiple myeloma

Introduction: Multiple myeloma (MM) is the second most commonly diagnosed hematologic malignancy and has an increasing incidence and prevalence globally, and proteasome inhibitors (PIs) form the backbone of some of our most effective regimens for all phases of this disease in fit and frail patients. Areas covered: Strong understanding of the proteasome complex is increasingly important as the rapid development of new PIs and innovative myeloma therapies complicate the use of old and new combination regimens. We focus herein on the pharmacodynamics and pharmacokinetics of the approved PIs and others in development, including their safety and efficacy in corresponding clinical studies. Expert opinion: Advancements such as the first oral PI, ixazomib, with a more convenient route of administration and improved toxicity profile led to an improved quality of life, patient compliance, and all-oral combination regimens which are efficacious for long-term management of standard and high-risk MM. Novel pan-PIs, such as marizomib, hold the promise of superior clinical activity due to irreversible targeting of all multicatalytic proteinase complex subunits. Development of clinically validated biomarkers of PI sensitivity/resistance is required to inform utilization of the most optimal and effective, rationally targeted PI treatments for all MM patients.

Carfilzomib for relapsed and refractory multiple myeloma

Although the prognosis of multiple myeloma (MM) patients has dramatically improved during recent years, virtually all patients eventually develop relapsed refractory disease. Several new therapeutics have been developed in the last few years, including carfilzomib, a second-generation proteasome inhibitor (PI) that has been approved by the US Food and Drug Administration (FDA) in the setting of relapsed and/or refractory MM, as a single agent with or without dexamethasone, and in combination with lenalidomide in 2012 and 2015, respectively. Other promising combinations with carfilzomib are being investigated. Carfilzomib has shown superiority over the first-generation PI bortezomib on both efficacy and toxicity. In particular, profoundly lower incidence in polyneuropathy compared to bortezomib has been described. However, carfilzomib has a different toxicity profile, with more cardiovascular adverse events. Therefore, caution should be taken with the use of carfilzomib for elderly and cardiovascularly compromised patients. The once-weekly administration of carfilzomib, recently approved by the FDA in combination with dexamethasone, will lead to a lower burden for the patient and caregivers compared to the twice-weekly schemes that were routinely used until recently. This review has a focus on clinical trial data that has led to drug approval, as well as new promising combination studies, and provides advice for treating physicians who are now prescribing this drug to patients.

Rutin inhibits carfilzomib-induced oxidative stress and inflammation via the NOS-mediated NF-κB signaling pathway

BACKGROUND

Carfilzomib (CFZ), a proteasome inhibitor approved by the FDA to treat multiple myeloma, may cause nephrotoxicity.

HYPOTHESIS

Rutin is a bioflavonoid with antioxidant properties. We aimed to examine whether rutin protects the kidney from CFZ-induced nephrotoxicity.

STUDY DESIGN

This study aimed to demonstrate the effect of rutin on CFZ-induced renal injury via the inhibition of oxidative stress and inflammation.

METHODS

Wistar albino rats were divided into six groups (n = 6): Group 1 (normal control; NC) was administered normal saline for 3 weeks; Group 2 (CFZ/toxic group) received CFZ [4 mg/kg, intraperitoneal (i.p.) injection] twice weekly for 3 weeks; Group 3 (standard treatment group) was administered CFZ (4 mg/kg, i.p.) and olmesartan (2 mg/kg, p.o.) for 3 weeks; Group 4 was administered CFZ (4 mg/kg, i.p.) and rutin (10 mg/kg, p.o.) for 3 weeks; Group 5 was administered CFZ (4 mg/kg, i.p.) and rutin (20 mg/kg, p.o.) for 3 weeks; and Group 6 was administered CFZ (4 mg/kg, i.p.) and rutin (40 mg/kg, p.o.) for 3 weeks. We carried out haematological and biochemical analyses, determined oxidative stress, caspase-3 activity, and protein levels, and performed a histopathological evaluation to confirm CFZ-induced nephrotoxicity and its prevention by rutin administration.

RESULTS

Exposure to only CFZ significantly (p < 0.05) increased white blood cell (WBC) count, Hb%, and HTC% concentration; however, these features were significantly decreased (p < 0.05) when olmesartan and rutin were administered. CFZ administration significantly decreased (p < 0.0001) the level of antioxidant enzymes; whereas, administration of olmesartan and rutin significantly reversed (p < 0.05) their levels toward the normal range. The levels of caspase-3 enzyme significantly increased (p < 0.001) in the CFZ group and were reduced toward the normal values by olmesartan and rutin administration. Furthermore, the results of NOS-2, NF-κB, IkBa, and IL-17 protein estimation and the histopathological evaluation strengthened our findings that rutin exhibits a protective effect against CFZ-induced nephrotoxicity.

CONCLUSION

These findings clearly demonstrate that rutin ameliorates CFZ-induced oxidative stress and inflammation in nephrotoxicity via the NOS-mediated NF-κB signaling pathway.

Cardiovascular adverse events in multiple myeloma patients

Multiple myeloma is a malignant disease, caused by an uncontrolled clonal proliferation of a specific group of white blood cells, the plasma cells. Clinical manifestations include bone pain due to osteolysis, hypercalcemia, anemia, and renal insufficiency. Proteasome inhibitors have substantially improved survival of patients suffering from multiple myeloma, providing an efficient treatment option mainly for relapsed and refractory multiple myeloma. Although constituting one substance class, bortezomib, carfilzomib, and ixazomib differ greatly regarding their non-hematologic side effects. This article reviews the clinical and preclinical data on approved proteasome inhibitors in an attempt to decipher the underlying pathomechanisms related to cardiovascular adverse events seen in clinical trials.

The role of carfilzomib in treatment of newly diagnosed multiple myeloma

Despite improvement of prognosis since approval of proteasome inhibitors and immunomodulatory drugs, myeloma remains largely incurable. The outcome of first-line treatment is known to be crucial for survival and, therefore, implementation of novel strategies remains one of the key aims of clinical myeloma research. Since approval of carfilzomib for relapsed and refractory multiple myeloma, a new therapeutic option with a favorable safety profile regarding neuropathy is available. Regarding its superior response rates and progression-free survival (PFS) when combined with other agents in heavily pretreated patients, the compound rapidly became a matter of great interest in search for first-line treatment. With an ORR up to 98% and promising PFS data, it might become an important partner in treatment of newly diagnosed myeloma.

Carfilzomib vs bortezomib in patients with multiple myeloma and renal failure: a subgroup analysis of ENDEAVOR

In ENDEAVOR, carfilzomib (56 mg/m²) and dexamethasone (Kd56) demonstrated longer progression-free survival (PFS) over bortezomib and dexamethasone (Vd) in patients with relapsed/refractory multiple myeloma (RRMM). Here we evaluated Kd56 vs Vd by baseline renal function in a post hoc exploratory subgroup analysis. The intent-to-treat population included 929 patients (creatinine clearance [CrCL] ≥15 to <50 mL/min, n = 85 and n = 99; CrCL 50 to <80 mL/min, n = 186 and n = 177; and CrCL ≥80 mL/min, n = 193 and n = 189 for Kd56 and Vd arms, respectively). In these respective subgroups, median PFS was 14.9 vs 6.5 months (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.320-0.757), 18.6 vs 9.4 months (HR, 0.48; 95% CI, 0.351-0.652), and not reached (NR) vs 12.2 months (HR, 0.60; 95% CI, 0.434-0.827) for those receiving Kd56 vs Vd, respectively; median overall survival (OS) was 42.1 vs 23.7 months (HR, 0.66; 95% CI, 0.443-0.989), 42.5 vs 32.8 months (HR, 0.83; 95% CI, 0.626-1.104), and NR vs 42.3 months (HR, 0.75; 95% CI, 0.554-1.009). Complete renal response (ie, CrCL improvement to ≥60 mL/min in any 2 consecutive visits if baseline CrCL <50 mL/min) rates were 15.3% (95% CI, 8.4-24.7) and 14.1% (95% CI, 8.0-22.6) for those receiving Kd56 vs Vd, respectively. In a combined Kd56 and Vd analysis, complete renal responders had longer median PFS (14.1 vs 9.4 months; HR, 0.805; 95% CI, 0.438-1.481) and OS (35.3 vs 29.7 months; HR, 0.91; 95% CI, 0.524-1.577) vs nonresponders. Grade ≥3 adverse event rates in the respective subgroups were 87.1% vs 79.4%, 84.4% vs 71.8%, and 77.1% vs 65.9% for those receiving Kd56 vs Vd, respectively. Thus, Kd56 demonstrated PFS and OS improvements over Vd in RRMM patients regardless of their baseline renal function. The ENDEAVOR trial was registered at www.clinicaltrials.gov as #NCT01568866.

Proteasome inhibitors for multiple myeloma

Therapeutic strategies for multiple myeloma have dramatically changed in the last two decades, especially after the introduction of proteasome inhibitors. The first-in-class proteasome inhibitor, bortezomib, was approved by the US Food and Drug Administration in 2003. Since then, it has been a backbone therapy for not only relapsed or refractory myeloma patients but also newly diagnosed multiple myeloma patients. Second-generation proteasome inhibitors, such as carfilzomib and ixazomib, have been approved, and three proteasome inhibitors were incorporated into several regimens with other cytotoxic agents, such as alkylating agents, immunomodulatory drugs and monoclonal antibodies. Because each proteasome inhibitor shows different properties with respect to adverse events, understanding and managing each adverse event of proteasome inhibitors are necessary for the continuation of therapy with minimal interruption of treatment. This review summarizes the recent advances in proteasome inhibitors used in the treatment of multiple myeloma.

Next-generation proteasome inhibitors for cancer therapy

Over 2 decades ago, the proteasome was considered a risky or even untenable therapeutic target. Today, proteasome inhibitors are a mainstay in the treatment of multiple myeloma (MM) and have sales in excess of 3 billion US dollars annually. More importantly, the availability of proteasome inhibitors has greatly improved the survival and quality of life for patients with MM. Despite the remarkable success of proteasome inhibitor therapies to date, the potential for improvement remains, and the development and optimal use of proteasome inhibitors as anticancer agents continues to be an active area of research. In this review, we briefly discuss the features and limitations of the 3 proteasome inhibitor drugs currently used in the clinic and provide an update on current efforts to develop next-generation proteasome inhibitors with the potential to overcome the limitations of existing proteasome inhibitor drugs.

Analysis of carfilzomib cardiovascular safety profile across relapsed and/or refractory multiple myeloma clinical trials

Carfilzomib is a selective proteasome inhibitor approved for the treatment of relapsed and/or refractory multiple myeloma (RRMM). It has significantly improved outcomes, including overall survival (OS), and shown superiority vs standard treatment with lenalidomide plus dexamethasone and bortezomib plus dexamethasone. The incidence rate of cardiovascular (CV) events with carfilzomib treatment has varied across trials. This analysis evaluated phase 1-3 trials with >2000 RRMM patients exposed to carfilzomib to describe the incidence of CV adverse events (AEs). In addition, the individual CV safety data of >1000 patients enrolled in the carfilzomib arm of phase 3 studies were compared with the control arms to assess the benefit-risk profile of carfilzomib. Pooling data across carfilzomib trials, the CV AEs (grade ≥3) noted included hypertension (5.9%), dyspnea (4.5%), and cardiac failure (4.4%). Although patients receiving carfilzomib had a numeric increase in the rates of any-grade and grade ≥3 cardiac failure, dyspnea, and hypertension, the frequency of discontinuation or death due to these cardiac events was low and comparable between the carfilzomib and control arms. Serial echocardiography in a blinded cardiac substudy showed no objective evidence of cardiac dysfunction in the carfilzomib and control arms. Moreover, carfilzomib had no significant effect on cardiac repolarization. Our results, including the OS benefit, showed that the benefit of carfilzomib treatment in terms of reducing progression or death outweighed the risk for developing cardiac failure or hypertension in most patients. Appropriate carfilzomib administration and risk factor management are recommended for elderly patients and patients with underlying risk factors.

Incidence and risk of cardiac toxicities in patients with relapsed and refractory multiple myeloma treated with carfilzomib

Purpose

Carfilzomib has been approved for use in relapsed and refractory multiple myeloma (RRMM). Cardiac toxicities have been reported with the use of carfilzomib. We aimed to determine the overall incidence and risk of cardiac toxicities in RRMM patients treated with carfilzomib using a meta-analysis.

Methods

We searched several databases for relevant articles. Prospective trials evaluating carfilzomib in RRMM patients with adequate data on cardiac toxicities were included for analysis. Pooled incidence, Peto ORs, and 95% CIs were calculated according to the heterogeneity of selected studies.

Results

A total of 2,607 RRMM patients from eight prospective trials were included. The pooled incidence of all-grade congestive heart failure (CHF) and ischemic heart disease (IHD) related to carfilzomib in RRMM patients was 5.5% (95% CI: 4.3%–6.9%) and 2.7% (95% CI: 1.1%–6.7%), respectively. In addition, the use of carfilzomib significantly increased all-grade (Peto OR 2.33, 95% CI: 1.56–3.48, p<0.001) and high-grade (Peto OR 3.22, 95% CI: 1.84–5.61, p<0.001) CHF when compared to controls, whereas there was no significantly increased risk of developing all-grade (Peto OR 1.31, 95% CI: 0.79–2.18, p=0.30) and high-grade (Peto OR 1.41, 95% CI: 0.73–2.72, p=0.31) IHD in RRMM patients receiving carfilzomib.

Conclusion

The use of carfilzomib in RRMM patients significantly increases the risk of developing CHF but not IHD. Clinicians should be cautious about the risk of CHF associated with carfilzomib to maximize the benefits and minimize the toxicities.

Efficacy and safety of carfilzomib in relapsed and/or refractory multiple myeloma: systematic review and meta-analysis of 14 trials

OBJECTIVE

Carfilzomib (Carf) is a second-generation proteasome inhibitor approved for patients with relapsed and/or refractory multiple myeloma (RRMM) who failed ≥ 1 prior lines of therapy. We performed a systematic review of Carf literature with meta-analysis to determine the efficacy and safety in RRMM patients.

METHODS

Based on literature search, we included a total of 14 eligible phase I/II, phase II and phase III Carf based clinical trials. The cumulative incidence and odds ratios (OR) were calculated with random effect model, using ''R'' software with metaphor package.

RESULTS

2906 evaluable RRMM patients from published clinical trials included. The pooled overall response rate (ORR) was 45% (95% CI: 29-62). The pooled clinical benefit rate (CBR) was 56% (95% CI: 41-71). OR from 3 randomized clinical trials showed that Carf significantly improved ORR and CBR compared to control groups (OR 2.4, P < 0.0001; 2.02, P = 0.0007, respectively). Subgroup analysis showed significantly better ORR (P < 0.0001) and CBR (P < 0.001) with combination regimens compared to monotherapy. Response was significantly higher with high dose of Carf (>20/27 mg/m2) compared to standard dose (ORR 65% vs. 35%, P = 0.03). Compared to control group, the OR of developing cardiotoxicity (P = 0.002) and hypertension (P < 0.0001) were significantly higher with Carf, while no difference in peripheral neuropathy (P = 0.28).

CONCLUSIONS

Carf produces significantly better responses with acceptable safety profile in RRMM patients. Combination regimens and higher dose Carf offers better response with no significant extra toxicity. Its efficacy is regardless of cytogenetics or disease stage. Incidences of cardiotoxicity and hypertension seem higher with Carf.

Carfilzomib-Associated Cardiovascular Adverse Events: A Systematic Review and Meta-analysis

Importance

Cardiovascular adverse events (CVAE) with carfilzomib in patients with multiple myeloma can be potentially life-threatening and remain incompletely characterized. We performed the first systematic review and meta-analysis of carfilzomib-associated CVAE.

Objective

To determine the incidence of carfilzomib-associated CVAE and to compare the rates of carfilzomib CVAE among different doses and companion therapies.

Data Sources

PubMed, EMBASE, Web of Science, and clinicaltrials.gov were queried for the keywords "carfilzomib," "Kyprolis," and "PX-171" through January 1, 2017.

Study Selection

Phase 1 to 3 prospective clinical trials of carfilzomib in patients with multiple myeloma with evaluable toxic effects data were eligible for meta-analysis.

Data Extraction and Synthesis

Data were independently extracted by 2 reviewers following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Pooled incidence rates and relative risks (for randomized trials) and 95% confidence intervals were calculated using a random effects model. Subgroup analyses were performed to assess study-level characteristics associated with CVAE.

Main Outcomes and Measures

Cardiovascular adverse events were defined as heart failure, hypertension, ischemia, and arrhythmia. All-grade and grades 3 or higher AEs and study characteristics were recorded.

Results

A total of 514 studies were assessed for eligibility. Of those, 24 studies were eligible, including a total of 2594 patients with multiple myeloma. All-grade and grades 3 and higher CVAE were seen in 617 (18.1%) and 274 (8.2%), respectively. Phase 2 or 3 studies and carfilzomib doses of 45 mg/m2 or higher were associated with high-grade CVAE. Median age older than 65 years, prior myeloma therapies, and concurrent myeloma therapies were not associated with CVAE. For the 3 randomized clinical trials, the summary relative risk of all-grade and grade 3 or higher CVAE for patients receiving carfilzomib compared with noncarfilzomib-receiving control patients were 1.8 and 2.2, respectively.

Conclusions and Relevance

Carfilzomib was associated with a significant incidence of CVAE, with higher rates seen with higher doses of carfilzomib. Phase 1 studies may be underdetecting CVAE. Future studies are needed to identify patients at high risk for CVAE, develop optimal monitoring strategies, and explore strategies to mitigate these risks.

Cardiotoxicity associated with carfilzomib: systematic review and meta-analysis

Carfilzomib is a second-generation proteasome inhibitor (PI) that is approved for patients with relapsed or refractory multiple myeloma (RRMM) who failed ≥1 prior lines of therapy. We performed a systematic review of carfilzomib literature with meta-analysis to determine cumulative incidence of cardiotoxicity. After the literature search, we included a total of 29 eligible phase I/II, phase II and phase III clinical trials which used carfilzomib. The cumulative incidence and overall odds ratios (OR) were calculated with random effect model, using 'R' software with metaphor package. A total of 4164 patients with various malignancies were included. The overall estimated cumulative incidence of cardiotoxicity was 8.68% and 4.92%, respectively, for all-grade and high-grade (≥ grade 3) toxicity, which seems higher than other PIs. Compared to control group, the odds of developing cardiotoxicity due to carfilzomib was significantly higher with OR of 2.03 (95% CI: 1.19-3.46, p = .010) and 2.04 (95% CI: 1.31-3.17, p = .002) for all-grades and high grades, respectively. Concomitant immunomodulatory agents seem to increase the risk of cardiotoxicity (high-grade cardiotoxicity 6.45% and 4.34% with and without concomitant immunomodulatory agents, respectively (p = .033)). There was no variation in the incidence of cardiotoxicity among newly diagnosed versus RRMM (p = .38), and high versus standard dose carfilzomib (p = .86).

The activity and safety of novel proteasome inhibitors strategies (single, doublet and triplet) for relapsed/refractory multiple myeloma

PURPOSE

We sought to evaluate the activity and safety of these novel proteasome inhibitors (PIs) (carfilzomib, ixazomib, oprozomib and marizomib) containing regimens (single, doublet and triplet) for relapsed/refractory multiple myeloma (R/RMM).

METHODS

We searched published reports including these novel PIs containing regimens for R/RMM.

RESULTS

Finally, we identified 28 prospective studies that evaluated 4123 patients. Pooled analysis showed that novel PIs doublet combinations attained an impressive overall response rate (ORR) of 67%, which was higher than that of 22% from novel PIs single-agent (p < .001). And, the same trends favoring novel PIs doublet combinations were also shown in at least very good partial response (≥VGPR) and clinical benefit rate (CBR) analysis. Meanwhile, the ORR of 70% from novel PIs triplet regimens seemed to be similar to that of 67% from novel PIs doublet combinations (p = .54). And, there were no difference between them in ≥VGPR and CBR analysis. Compared to standard therapy, novel PIs combinations clearly benefited patients with R/RMM in terms of overall survival (HR, 0.79; p= .01), progression free survival(HR, 0.64; p = .01), overall response rate (RR = 1.21 p < .001).

CONCLUSIONS

Novel PIs doublet combinations attained superior response outcomes over novel PIs single-agent in patients with R/RMM. Meanwhile, novel PIs triplet combinations had similar response outcomes with novel PIs doublet combinations. Compared to standard therapy, novel PIs combinations clearly prolonged survival for patients with R/RMM.

Nephrotoxicity of anticancer treatment

Severe adverse systemic drug events occur commonly as a result of treatment of cancer patients. Nephrotoxicity of chemotherapeutic agents remains a significant complication limiting the efficacy of the treatment. A variety of renal disease and electrolyte disorders can result from the drugs that are used to treat malignant disease. The kidneys are a major elimination pathway for many antineoplastic drugs and their metabolites. Tumour lysis syndrome, an emergency in haematooncology, occurs most often after the initiation of cytotoxic therapy in patients with high-grade lymphomas and acute lymphoblastic leukaemia. Chemotherapeutic agents can affect the glomerulus, tubules, interstitium and renal microvasculature, with clinical manifestations that range from asymptomatic elevation of serum creatinine to acute renal failure requiring dialysis. Some factors such as intravascular volume depletion, as well as concomitant use of other drugs or radiographic ionic contrast media, can potentiate or contribute to the nephrotoxicity. Cytotoxic agents can cause nephrotoxicity by a variety of mechanisms. The most nephrotoxic chemotherapeutic drug is cisplatin, which is often associated with acute kidney injury. Many other drugs such as alkylating agents, antimetabolites, vascular endothelial growth factor pathway inhibitors and epidermal growth factor receptor pathway inhibitors may have toxic effects on the kidneys. The aim of this review is to discuss the issue of nephrotoxicity associated with chemotherapy. In routine clinical practice, monitoring of kidney function is mandatory in order to identify nephrotoxicity early, allowing dosage adjustments or withdrawal of the offending drug.

Carfilzomib

Carfilzomib (CFZ) is a potent, second-generation proteasome inhibitor (PI), with significant activity as a single agent and in combination with other antimyeloma agents in patients with relapsed or refractory multiple myeloma (RRMM). CFZ binds selectively and irreversibly to its target and leads to antiproliferative and proapoptotic effects on cancer cells. This irreversible inhibition is dose- and time-dependent in vitro and in vivo. CFZ as monotherapy and in combination with other antimyeloma agents (e.g., as CFZ and dexamethasone [Kd]) achieved very good responses, progression-free survival (PFS) and overall survival (OS). In several ongoing studies, CFZ is being investigated in triplet and quadruplet schedules of CFZ, lenalidomide and dexamethasone (KRd), CFZ, cyclophosphamide, dexamethasone (KCd) and with antibodies, like elotuzumab or daratumumab. The multitude of completed and ongoing studies confirmed a tolerable safety profile of CFZ, a significantly lower incidence of neuropathy compared to bortezomib (BTZ) and a slightly higher incidence of cardiotoxicity, which is closely observed and precautions taken to avoid them as best as possible. In July 2012, the US Food and Drug Administration (FDA) approved CFZ as a single agent for RRMM patients with disease progression after two prior therapies, including BTZ and immunomodulatory drugs (IMiDs). The combination of KRd and Kd followed, being approved by both FDA and European Medicines Agency (EMA) in 2015 and 2016, respectively. Moreover, CFZ is being evaluated in patients with newly diagnosed MM (NDMM), in high-risk smoldering MM and for maintenance approaches.

Improving the efficacy of proteasome inhibitors in the treatment of renal cell carcinoma by combination with the human immunodeficiency virus (HIV)-protease inhibitors lopinavir or nelfinavir

OBJECTIVES

To assess the potential of second-generation proteasome inhibition by carfilzomib and its combination with the human immunodeficiency virus (HIV) protease inhibitors (HIV-PIs) lopinavir and nelfinavir in vitro for improved treatment of clear cell renal cell cancer (ccRCC).

MATERIALS AND METHODS

Cytotoxicity, reactive oxygen species (ROS) production, and unfolded protein response (UPR) activation of proteasome inhibitors, HIV-PIs, and their combination were assessed in three cell lines and primary cells derived from three ccRCC tumours by MTS assay, flow cytometry, quantitative reverse transcriptase-polymerase chain reaction and western blot, respectively. Proteasome activity was determined by activity based probes. Flow cytometry was used to assess apoptosis by annexin V/propidium iodide assay and ATP-binding cassette sub-family B member 1 (ABCB1) activity by MitoTracker™ Green FM efflux assay (Thermo Fisher Scientific, MA, USA).

RESULTS

Lopinavir and nelfinavir significantly increased the cytotoxic effect of carfilzomib in all cell lines and primary cells. ABCB1 efflux pump inhibition, induction of ROS production, and UPR pre-activation by lopinavir were identified as underlying mechanisms of this strong synergistic effect. Combined treatment led to unresolved protein stress, increased activation of pro-apoptotic UPR pathway, and a significant increase in apoptosis.

CONCLUSION

The combination of the proteasome inhibitor carfilzomib and the HIV-PIs lopinavir and nelfinavir has a strong synergistic cytotoxic activity against ccRCCin vitro at therapeutically relevant drug concentrations. This effect is most likely explained by synergistic UPR triggering and ABCB1-modulation caused by HIV-PIs. Our findings suggest that combined treatment of second-generation proteasome inhibitors and HIV-PIs should be investigated in patients with metastatic RCC within a clinical trial.

A survey of renal impairment pharmacokinetic studies for new oncology drug approvals in the USA from 2010 to early 2015: a focus on development strategies and future directions

The US Food and Drug Administration (FDA) issued a guidance document in 2010 on pharmacokinetic (PK) studies in renal impairment (RI) on the basis of observations that substances such as uremic toxins might result in altered drug metabolism and excretion. No specific recommendations for oncology drugs were included. We surveyed the publicly available FDA review documents of 29 small molecule oncology drugs approved between 2010 and the first quarter of 2015. The objectives were as follows: (i) summarize the impact of RI on PK at the time of the initial new drug application; (ii) identify limitations of the guidance; and (iii) outline an integrated approach to study the impact of RI on these drugs. Our survey indicates that the current FDA guidance does not appear to provide clear strategic or decision pathways for RI studies in terms of small molecule oncology drugs. The FDA review documents indicate an individualized approach to the review because of the complex pharmacologic nature of these drugs and patient populations. Overall, the strategy for carrying out a RI study during clinical development or as a postmarketing study requires integration with the totality of data, including mass balance, absolute bioavailability, drug–drug interaction, hepatic dysfunction, population PK, exposure–response analysis, the therapeutic window for best guidance, and determination of the optimal doses for special oncology populations.

An overview of the role of carfilzomib in the treatment of multiple myeloma

INTRODUCTION

Carfilzomib is a second-generation proteasome inhibitor that binds selectively and irreversibly with the chymotrypsin-like site of the proteolytic core. Its initial approval by the Food and Drug Administration, as monotherapy for relapsed/refractory multiple myeloma (RR-MM), followed soon by a global authorization of its combination with dexamethasone or with lenalidomide plus dexamethasone for the treatment of RR-MM after 1-3 prior lines. In order to optimize its administration, carfilzomib is currently examined in different doses and regimens in relapsed/refractory as well as in newly diagnosed myeloma. Areas covered: This review will focus on the introduction of carfilzomib as an effective anti-myeloma treatment, describing the evolution of the drug from its pre-clinical development to its established use by phase III clinical trials. Based on the latest evidence, we will present its mechanism of action, its efficacy and its toxicity profile on treated myeloma patients and we will try to reply to all raised concerns about its current use. Expert opinion: Either alone or in combination with other agents, carfilzomib seems to be an effective and safe therapeutic option for MM management. Results of ongoing trials are expected to update its application, even at an earlier level of the disease course.

Disease and Symptom Care: A Focus on Specific Needs of Patients With Multiple Myeloma

Patients with multiple myeloma (MM) often deal with short- and long-term side effects of the treatment and disease sequelae. Reasons for inadequately managed symptoms are multifactorial (e.g., the patient may fear treatment interruption, the clinician does not assess or address the symptoms) and can affect patients' ability to remain on the recommended treatment. This article provides background surrounding this supplement's development and describes the importance of symptom assessment and management.
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Immunoproteasome-selective and non-selective inhibitors: A promising approach for the treatment of multiple myeloma

The ubiquitin-proteasome system (UPS) is the major non-lysosomal proteolytic system for the degradation of abnormal or damaged proteins no longer required. The proteasome is involved in degradation of numerous proteins which regulate the cell cycle, indicating a role in controlling cell proliferation and maintaining cell survival. Defects in the UPS can lead to anarchic cell proliferation and to tumor development. For these reasons UPS inhibition has become a significant new strategy for drug development in cancer treatment. In addition to the constitutive proteasome, which is expressed in all cells and tissues, higher organisms such as vertebrates possess two immune-type proteasomes, the thymoproteasome and the immunoproteasome. The thymoproteasome is specifically expressed by thymic cortical epithelial cells and has a role in positive selection of CD8+ T cells, whereas the immunoproteasome is predominantly expressed in monocytes and lymphocytes and is responsible for the generation of antigenic peptides for cell-mediated immunity. Recent studies demonstrated that the immunoproteasome has a preservative role during oxidative stress and is up-regulated in a number of pathological disorders including cancer, inflammatory and autoimmune diseases. As a consequence, immunoproteasome-selective inhibitors are currently the focus of anticancer drug design. At present, the commercially available proteasome inhibitors bortezomib and carfilzomib which have been validated in multiple myeloma and other model systems, appear to target both the constitutive and immunoproteasomes, indiscriminately. This lack of specificity may, in part, explain some of the side effects of these agents, such as peripheral neuropathy and gastrointestinal effects, which may be due to targeting of the constitutive proteasome in these tissues. In contrast, by selectively inhibiting the immunoproteasome, it may be possible to maintain the antimyeloma and antilymphoma efficacy while reducing these toxicities, thereby increasing the therapeutic index. This review article will be focused on the discussion of the most promising immunoproteasome specific inhibitors which have been developed in recent years. Particular attention will be devoted to the description of their mechanism of action, their structure-activity relationship, and their potential application in therapy.

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.

Carfilzomib/pomalidomide single-agent or in combination with other agents for the management of relapsed/refractory multiple myeloma: a meta-analysis of 37 trials

PURPOSE

The use of carfilzomib/pomalidomide single-agent or in combination with other agents in patients with refractory/relapsed multiple myeloma (RRMM) was not clearly clarified in clinical practice. We sought to compile the available clinical reports to better understand the efficacy and safety of carfilzomib (CFZ) and pomalidomide (POM).

RESULTS

Based on our research criteria, we identified 37 prospective studies that evaluated 1160 patients. Analysis of subgroup differences between carfilzomib single-agent and CFZ/DEX dual combination showed significantly(P < 0.001, I2 = 96.3%), suggesting the overall response rate (ORR) of 66% attained from CFZ/DEX dual combination seemed to be higher than that of 28% from carfilzomib single-agent. And, the same trend favoring CFZ/DEX dual combination was found in ≥VGPR and CBR analysis. The ORR of 31% attained from POM/DEX dual combination was superior to that of 19% from pomalidomide single-agent(P < 0.001, I2 = 94.4%). And, the same trend favoring POM/DEX dual combination was found in ≥VGPR and CBR analysis. However, the ORR of 83% attained from POM/BOR/DEX triplet combination was superior to that of 31% from POM/DEX dual combination(P < 0.001, I2 = 99.1%). And, the same trend favoring POM/BOR/DEX triplet combination was found in ≥VGPR analysis.

METHODS

We searched published reports including carfilzomib and (or) pomalidomide therapy for RRMM who had received bortezomib and (or) lenalidomide.

CONCLUSION

Pomalidomide/Carfilzomib plus dexamethasone seemed to attain a superior response rate compared with pomalidomide/carfilzomib single-agent. Furthermore, the combination of pomalidomide, bortezomib and dexamethasone resulted in a much higher response rate compared with pomalidomide plus dexamethasone regimen. These results needed more validation in future trials.