Bortezomib-induced peripheral neuropathy in multiple myeloma: a comprehensive review of the literature. Blood. 2008;112:1593-1599. [PMID: 18574024 DOI: 10.1182/blood-2008-04-149385]

Amyloid Neuropathy: From Pathophysiology to Treatment in Light-Chain Amyloidosis and Hereditary Transthyretin Amyloidosis

Amyloid neuropathy is caused by deposition of insoluble β-pleated amyloid sheets in the peripheral nervous system. It is most common in: (1) light-chain amyloidosis, a clonal non-proliferative plasma cell disorder in which fragments of immunoglobulin, light or heavy chain, deposit in tissues, and (2) hereditary transthyretin (ATTRv) amyloidosis, a disorder caused by autosomal dominant mutations in the TTR gene resulting in mutated protein that has a higher tendency to misfold. Amyloid fibrils deposit in the endoneurium of peripheral nerves, often extensive in the dorsal root ganglia and sympathetic ganglia, leading to atrophy of Schwann cells in proximity to amyloid fibrils and blood-nerve barrier disruption. Clinically, amyloid neuropathy is manifested as a length-dependent sensory predominant neuropathy associated with generalized autonomic failure. Small unmyelinated nerves are involved early and prominently in early-onset Val30Met ATTRv, whereas other ATTRv and light-chain amyloidosis often present with large- and small-fiber involvement. Nerve conduction studies, quantitative sudomotor axon testing, and intraepidermal nerve fiber density are useful tools to evaluate denervation. Amyloid deposition can be demonstrated by tissue biopsy of the affected organ or surrogate site, as well as bone-avid radiotracer cardiac imaging. Treatment of light-chain amyloidosis has been revolutionized by monoclonal antibodies and stem cell transplantation with improved 5-year survival up to 77%. Novel gene therapy and transthyretin stabilizers have revolutionized treatment of ATTRv, improving the course of neuropathy (less change in the modified Neuropathy Impairment Score + 7 from baseline) and quality of life. With great progress in amyloidosis therapies, early diagnosis and presymptomatic testing for ATTRv family members has become paramount. ANN NEUROL 2024;96:423-440.

Beyond Population-Level Targets for Drug Concentrations: Precision Dosing Needs Individual-Level Targets that Include Superior Biomarkers of Drug Responses

The purpose of precision dosing is to increase the chances of therapeutic success in individual patients. This is achieved in practice by adjusting doses to reach precision dosing targets determined previously in relevant populations, ideally with robust supportive evidence showing improved clinical outcomes compared with standard dosing. But is this implicit assumption of translatable population-level precision dosing targets correct and the best for all patients? In this review, the types of precision dosing targets and how they are determined are outlined, problems with the translatability of these targets to individual patients are identified, and ways forward to address these challengers are proposed. Achieving improved clinical outcomes to support precision dosing over standard dosing is currently hampered by applying population-level targets to all patients. Just as "one-dose-fits-all" may be an inappropriate philosophy for drug treatment overall, a "one-target-fits-all" philosophy may limit the broad clinical benefits of precision dosing. Defining individual-level precision dosing targets may be needed for greatest therapeutic success. Superior future precision dosing targets will integrate several biomarkers that together account for the multiple sources of drug response variability.

Genetic Risk Factors for Bortezomib-induced Neuropathic Pain in an Asian Population: A Genome-wide Association Study in South Korea

Bortezomib-induced neuropathic pain (BINP) poses a challenge in multiple myeloma (MM) treatment. Genetic factors play a key role in BINP susceptibility, but research has predominantly focused on Caucasian populations. This research explored novel genetic risk loci and pathways associated with BINP development in Korean MM patients while evaluating the reproducibility of variants from Caucasians. Clinical data and buffy coat samples from 185 MM patients on bortezomib were collected. The cohort was split into discovery and validation cohorts through random stratification of clinical risk factors for BINP. Genome-wide association study was performed on the discovery cohort (n = 74) with Infinium Global Screening Array-24 v3.0 BeadChip (654,027 single nucleotide polymorphism [SNPs]). Relevant biological pathways were identified using the pathway scoring algorithm. The top 20 SNPs were validated in the validation cohort (n = 111). Previously reported SNPs were validated in the entire cohort (n = 185). Pathway analysis of the genome-wide association study results identified 31 relevant pathways, including immune systems and endosomal vacuolar pathways. Among the top 20 SNPs from the discovery cohort, 16 were replicated, which included intronic variants in ASIC2 and SMOC2, recently implicated in nociception, as well as intergenic variants or long noncoding RNAs. None of the 17 previously reported SNPs remained significant in our cohort (rs2274578, P = .085). This study represents the first investigation of novel genetic loci and biological pathways associated with BINP occurrence. Our findings, in conjunction with existing Caucasian studies, expand the understanding of personalized risk prediction and disease mechanisms. PERSPECTIVE: This article is the first to explore novel genetic loci and pathways linked to BINP in Korean MM patients, offering novel insights beyond the existing research focused on Caucasian populations into personalized risk assessment and therapeutic strategies of BINP.

Reporting of adverse events of treatment interventions in multiple myeloma: an overview of systematic reviews

The present study is an overview of systematic reviews focusing on adverse events of antimyeloma treatments. It provides a systematic description of adverse events as they are reported in the systematic reviews as well as a critical appraisal of included reviews. We conducted a comprehensive literature search in the most widely used electronic databases looking for systematic reviews that had an adverse event of an antimyeloma treatment intervention as primary outcome. Two independent reviewers conducted selection of included studies and data extraction on predesigned online forms and assessed study quality using AMSTAR 2. Overall corrected covered area (CCA) was calculated to examine the overlap of primary studies across systematic reviews. After screening eligible studies, 23 systematic reviews were included in this overview. Seven reviews with overall CCA of 14.7% examined cardiovascular adverse events of different drugs, including immunomodulatory drugs and proteasome inhibitors (mainly carfilzomib). Nine focused on infections, presenting with overall CCA of 5.8%, each one focused on a different drug or drug class. Three studied thromboembolism in patients treated either with lenalidomide, any immunomodulatory drug, or with daratumumab and had an overall CCA equal to 1.5%. Four more reviews focused on bortezomib-associated neurotoxicity, carfilzomib-associated renal toxicity, or second primary malignancies as an adverse event of lenalidomide or anti-CD38 monoclonal antibody treatment. The quality of included studies as judged by AMSTAR 2 was mostly critically low. Absence of a priori registered protocol and formal assessment of risk of bias of included primary studies were the most common shortcomings. Reporting of antimyeloma drug-associated toxicity is supported by multiple systematic reviews; nevertheless, methodological quality of existing reviews is mostly low.

Multiple myeloma

Multiple myeloma (MM) is a haematological lymphoid malignancy involving tumoural plasma cells and is usually characterized by the presence of a monoclonal immunoglobulin protein. MM is the second most common haematological malignancy, with an increasing global incidence. It remains incurable because most patients relapse or become refractory to treatments. MM is a genetically complex disease with high heterogeneity that develops as a multistep process, involving acquisition of genetic alterations in the tumour cells and changes in the bone marrow microenvironment. Symptomatic MM is diagnosed using the International Myeloma Working Group criteria as a bone marrow infiltration of ≥10% clonal plasma cells, and the presence of at least one myeloma-defining event, either standard CRAB features (hypercalcaemia, renal failure, anaemia and/or lytic bone lesions) or biomarkers of imminent organ damage. Younger and fit patients are considered eligible for transplant. They receive an induction, followed by consolidation with high-dose melphalan and autologous haematopoietic cell transplantation, and maintenance therapy. In older adults (ineligible for transplant), the combination of daratumumab, lenalidomide and dexamethasone is the preferred option. If relapse occurs and requires further therapy, the choice of therapy will be based on previous treatment and response and now includes immunotherapies, such as bi-specific monoclonal antibodies and chimeric antigen receptor T cell therapy.

Visual analysis of global research on the transient receptor potential ankyrin 1 channel: A literature review from 2002 to 2022

Background and aims

The transient receptor potential ankyrin 1 (TRPA1) channel has become a focus in pain research. However, there are no bibliometric studies that systematically analyze the existing research in this area. This study aimed to provide a systematic review of the existing literature on TRPA1 using a bibliometric analysis.

Methods

Published literature in the field of TRPA1 was collected from the Web of Science Core Collection database. Quantitative and qualitative analyses of publications, countries, institutions, authors, journals, and other entries were conducted using Excel, VOSview, and Citespace software to provide insight into global research hotspots and trends in the TRPA1 field.

Results

This study included 1189 scientific products published in 398 journals from 52 countries. The United States of America (n = 367) had the most publications, ahead of Japan (n = 212) and China (n = 199). The University of Florence (n = 55) was the most productive institution and Pierangelo Geppetti (n = 46) was the most productive author. PLoS One (n = 40) published the most articles on TRPA1. Pain, cold, inflammation, covalent modification, hyperalgesia, and oxidative stress were the most common keywords used in the studies.

Conclusion

This study provides the first bibliometric analysis of TRPA1 publications. The physiological functions of TRPA1, TRPA1, and neuropathic pain, TRPA1 as a therapeutic target, and agonists of TRPA1 are trending in TRPA1 research. Neuropathic pain, apoptosis, and sensitization could be focus areas of future research. This study provides important insight in the field of TRPA1 research.

Bortezomib-induced peripheral neuropathy: Clinical features, molecular basis, and therapeutic approach

Bortezomib is the first-line standard and most effective chemotherapeutic for multiple myeloma; however, bortezomib-induced peripheral neuropathy (BIPN) severely affects the chemotherapy regimen and has long-term impact on patients under maintenance therapy. The pathogenesis of BIPN is poorly understood, and basic research and development of BIPN management drugs are in early stages. Besides chemotherapy dose reduction and regimen modification, no recommended prevention and treatment approaches are available for BIPN apart from the International Myeloma Working Group guidelines for peripheral neuropathy in myeloma. An in-depth exploration of the pathogenesis of BIPN, development of additional therapeutic approaches, and identification of risk factors are needed. Optimizing effective and standardized BIPN treatment plans and providing more decision-making evidence for clinical diagnosis and treatment of BIPN are necessary. This article reviews the recent advances in BIPN research; provides an overview of clinical features, underlying molecular mechanisms, and therapeutic approaches; and highlights areas for future studies.

Histone deacetylase (HDAC) inhibitor specificity determinants are preserved in a class of dual HDAC/non-covalent proteasome inhibitors

Many disease states require multiple drugs to inhibit multiple targets for their effective treatment/management, i.e. a drug cocktail regimen, or "polypharmacy". Polypharmacology, in contrast, is the development of single agents that can inhibit multiple targets. Each strategy is associated with advantages and disadvantages. Motivated by promising clinical trial data for the treatment of multiple myeloma with the combination of the HDAC6 inhibitor ricolinostat and the proteasome inhibitor bortezomib, we herein describe a focused family of dual HDAC/non-covalent proteasome inhibitors, and explore the impact of linker and zinc-binding group identities on HDAC1/6 isozyme selectivity. In general, previously reported specificity determinants of monovalent HDAC1/6 inhibitors were preserved in our dual HDAC/proteasome inhibitors.

TRAIL-induced apoptosis and proteasomal activity - Mechanisms, signalling and interplay

Programmed cell death, in particular apoptosis, is essential during development and tissue homeostasis, and also is the primary strategy to induce cancer cell death by cytotoxic therapies. Precision therapeutics targeting TRAIL death receptors are being evaluated as novel anti-cancer agents, while in parallel highly specific proteasome inhibitors have gained approval as drugs. TRAIL-dependent signalling and proteasomal control of cellular proteostasis are intricate processes, and their interplay can be exploited to enhance therapeutic killing of cancer cells in combination therapies. This review provides detailed insights into the complex signalling of TRAIL-induced pathways and the activities of the proteasome. It explores their core mechanisms of action, pharmaceutical druggability, and describes how their interplay can be strategically leveraged to enhance cell death responses in cancer cells. Offering this comprehensive and timely overview will allow to navigate the complexity of the processes governing cell death mechanisms in TRAIL- and proteasome inhibitor-based treatment conditions.

Once-weekly versus twice-weekly bortezomib in newly diagnosed multiple myeloma: a real-world analysis

Induction regimens for multiple myeloma (MM) commonly include bortezomib, which has typically been administered twice weekly despite studies demonstrating comparable efficacy and less peripheral neuropathy (PN) with once-weekly bortezomib. We aimed to analyze the real-world prevalence and efficacy of once-weekly versus twice-weekly bortezomib regimens in newly diagnosed MM. We analyzed 2497 US patients aged 18-70 years treated with commercial first-line bortezomib using nationwide Flatiron Health electronic health record-derived data, including 910 (36.4%) patients who received twice-weekly and 1522 (63.2%) who received once-weekly bortezomib. Once-weekly bortezomib use increased over time, from 57.7% in 2017 to 73.1% in 2022. Multivariate analysis identified worsened performance status and more recent year of diagnosis with higher odds of receiving once-weekly bortezomib. Real-world progression-free survival (median 37.2 months with once-weekly versus 39.6 months with twice-weekly, p = 0.906) and overall survival (medians not reached in either cohort, p = 0.800) were comparable. PN rates were higher in patients receiving twice-weekly bortezomib (34.7% versus 18.5%, p < 0.001). In conclusion, once-weekly bortezomib is clearly associated with similar efficacy and fewer toxicities compared to twice-weekly bortezomib. Our findings support once-weekly bortezomib as a standard-of-care regimen for newly diagnosed patients with MM.

Efficacy and safety of daratumumab with ixazomib and dexamethasone in lenalidomide-exposed patients after one prior line of therapy: Final results of the phase 2 study DARIA

The use of lenalidomide in frontline therapy for patients with newly diagnosed multiple myeloma (MM) has increased the number of those who become refractory to lenalidomide at second line. In this context, we assessed the efficacy of daratumumab in combination with ixazomib and dexamethasone (Dara-Ixa-dex) in the prospective phase 2 study DARIA. Eligible patients had relapsed/refractory MM (RRMM) after one prior line with a lenalidomide-based regimen. The primary endpoint was overall response rate (ORR). Secondary endpoints included survival outcomes, safety and changes in biomarkers of bone metabolism. Overall, 50 patients were enrolled (median age 69 years, 56% males). 32 (64%) patients were refractory to lenalidomide, and 17 (34%) had undergone autologous transplant. The ORR was 64% (n = 32); whereas 17 (34%) had a very good partial response or better. The median time to first response was 1.0 month. After a median follow-up of 23.4 months, the median PFS and OS were 8.1 and 39.2 months, respectively. Furthermore, significant changes in markers of bone metabolism became evident as early as at 6 months on treatment. Regarding safety, 21 (42%) patients had ≥1 grade 3/4 adverse event (AE); the most common was thrombocytopenia (n = 9, 18%). 14 (28%) patients had ≥1 serious AE (SAE), the most common being acute kidney injury and pneumonia (n = 2, each). Four patients died due to infections. In conclusion, second-line treatment with Dara-Ixa-dex in patients with RRMM pre-treated with a lenalidomide-based regimen resulted in rapid responses along with a favorable effect on bone metabolism.

Venous Thromboembolism Risk in Patients With Newly Diagnosed Multiple Myeloma Treated with Carfilzomib or Bortezomib in Combination With Lenalidomide and Dexamethasone

BACKGROUND

Multiple myeloma (MM), as well as some treatments for MM, increase the risk of venous thromboembolism (VTE). Prior literature suggests carfilzomib, lenalidomide, and dexamethasone (KRd) may have a higher incidence of thromboembolic events compared with bortezomib, lenalidomide, and dexamethasone (VRd). We aimed to evaluate VTE risk with KRd induction compared to VRd at a large academic medical center in the United States.

MATERIALS AND METHODS

We retrospectively reviewed patients with newly diagnosed MM presenting at a single institution. Patients were followed for objectively diagnosed VTE events for 6 months following the start of induction therapy.

RESULTS

A total of 209 patients were included, with 69 (33%) receiving KRd and 140 (67%) receiving VRd. Overall, 18 patients (9%) had a VTE event, with 5 (7%) in the KRd cohort and 13 (9%) in the VRd cohort (P = .80). Treatment with KRd was not associated with an increased risk of VTE compared to VRd (HR 0.74; 95% CI 0.26-2.08; P = .57).

CONCLUSION

In this cohort, KRd was not associated with an increase in VTE risk compared to VRd, contrary to prior literature.

Repetitive transcranial magnetic stimulation for chemotherapy-induced peripheral neuropathy in multiple myeloma: A pilot study

Objective

Chemotherapy-induced peripheral neuropathy is one of the major toxicities in multiple myeloma patients, often resulting in dose reductions or treatment interruptions. Repetitive transcranial magnetic stimulation is a safe non-invasive neuromodulation therapy with potential benefits for chemotherapy-induced peripheral neuropathy. The objective of this study was to investigate the efficacy of repetitive transcranial magnetic stimulation treatment on chemotherapy-induced peripheral neuropathy in multiple myeloma patients.

Materials and methods

We screened 30 multiple myeloma patients with chemotherapy-induced peripheral neuropathy who underwent repetitive transcranial magnetic stimulation treatment in this study. Prior to and following repetitive transcranial magnetic stimulation treatment, patients were assessed with nerve conduction velocity, visual analog scale and the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale (EORTC QLQ-CIPN20). Categorical and continuous variables were analyzed using Fisher's exact test and Mann-Whitney U test respectively. A p-value < 0.05 (2-tailed) was considered statistically significant.

Results

Following repetitive transcranial magnetic stimulation treatment, 24/30 (80.0%) patients reported a reduction in chemotherapy-induced peripheral neuropathy symptoms. Meanwhile, all 15 patients with grade 2 chemotherapy-induced peripheral neuropathy experienced improvements about themselves, compared to 8/10 patient with grade 3 chemotherapy-induced peripheral neuropathy and 1/5 with grade 4 chemotherapy-induced peripheral neuropathy. Visual analog scale scores decreased after repetitive transcranial magnetic stimulation treatment (5.40 ± 1.94 vs 3.10 ± 1.60, p < 0.001). We also observed enhancements in both motor conduction velocity and sensory conduction velocity of patients in bilateral median nerves, posterior tibial nerves, common ulnar nerves and peroneal nerves following repetitive transcranial magnetic stimulation treatment. Analysis of the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale data (17.68 ± 8.14 vs 10.50 ± 9.55, p < 0.001) revealed significant reductions in scores. Patients with grade 2-3 (n = 25) exhibited a mean reduction of 8.89 ± 4.24 points, while those with grade 4 (n = 5) showed a difference value of 3.54 ± 3.45, p < 0.001. No adverse events were observed.

Conclusion

Our findings suggest that repetitive transcranial magnetic stimulation is a safe and effective therapeutic approach for ameliorating peripheral nerve injury and alleviating the chemotherapy-induced peripheral neuropathy symptoms in multiple myeloma patients. Early initiation of repetitive transcranial magnetic stimulation treatment may yield more favorable outcomes for these patients.

Investigation of the frequency of bortezomib neuropathy in patients with multiple myeloma diagnosis with normal and abnormal genetic characteristics

INTRODUCTION

Bortezomib-induced peripheral neuropathy in patients with multiple myeloma is an undesirable and sometimes severe side effect. Our study aimed to examine whether there was a difference in bortezomib-induced peripheral neuropathy between multiple myeloma patients with normal and abnormal genetic characteristics.

METHODS

This retrospective analysis is based on the assessment of bortezomib-induced peripheral neuropathy frequency in newly-diagnosed multiple myeloma patients with normal (n = 68) and abnormal (n = 45) genetic profiles. A total of 113 patients diagnosed with multiple myeloma according to the International Myeloma Working Group criteria, between 2016 and 2021, were included in this study.

RESULTS

Neuropathy was detected in 42 (37.1%) patients. The most common genetic anomalies were 13q del (in 28.9%), t(4.14) (in 22.2%), and trisomy 7 (in 20.0%). When patients with and without bortezomib-induced peripheral neuropathy were compared, the only significant differences were observed for age (p = 0.032) and genetic grouping (p = 0.001); whereas other characteristics that could be associated with bortezomib-induced peripheral neuropathy were similarly distributed in both groups. Bortezomib-induced peripheral neuropathy was significantly more frequent in multiple myeloma patients with normal genetic characteristics (p = 0.001).

CONCLUSION

As a result of our study, it was observed that the frequency of bortezomib neuropathy was significantly higher in patients with normal genetic features compared to those with abnormal genetic features. This result suggested that factors other than genetic factors should be investigated to clarify the etiology of bortezomib-associated neuropathy in patients with multiple myeloma.

Impact of Black Race on Peripheral Neuropathy in Patients With Newly Diagnosed Multiple Myeloma Receiving Bortezomib Induction

PURPOSE

The incidence of multiple myeloma (MM) is two to three times higher in Black patients compared with other races, making it the most common hematologic malignancy in this patient population. Current treatment guidelines recommend the combination of a proteasome inhibitor, an immunomodulatory agent, and a corticosteroid as preferred induction therapy. Bortezomib use comes with the risk of peripheral neuropathy (PN) and potential need for dose reduction, therapy interruption, and additional supportive medications. Known risk factors for bortezomib-induced peripheral neuropathy (BIPN) include diabetes mellitus, previous thalidomide, advanced age, and obesity. We aimed to determine the potential association between Black race and incidence of BIPN.

PATIENTS AND METHODS

We identified a cohort of 748 patients with newly diagnosed MM who received induction with bortezomib, lenalidomide, and dexamethasone from 2007 to 2016. One hundred forty Black patients were matched with 140 non-Black patients on age, sex, BMI, and route of bortezomib administration. Incidence of BIPN was a binary event defined as new use of a neuropathy medication, bortezomib dose reduction, dose omission, or discontinuation because of PN.

RESULTS

The incidence of BIPN was higher in Black patients (46%) compared with non-Black patients (34%; P = .05) in both univariate (odds ratio [OR], 1.61; 95% CI, 1.00 to 2.61; P = .052) and multivariable analyses (OR, 1.64; 95% CI, 1.01 to 2.67; P = .047). No significant differences in BIPN were seen when stratified by route of administration.

CONCLUSION

These data indicate that Black race is an independent risk factor for the development of BIPN. Additional prevention strategies, close monitoring, and appropriate supportive care measures are warranted for these patients.

Prediction of cancer nanomedicines self-assembled from meta-synergistic drug pairs

Combination therapy is widely used in cancer medicine due to the benefits of drug synergy and the reduction of acquired resistance. To minimize emergent toxicities, nanomedicines containing drug combinations are being developed, and they have shown encouraging results. However, developing multi-drug loaded nanoparticles is highly complex and lacks predictability. Previously, it was shown that single drugs can self-assemble with near-infrared dye, IR783, to form cancer-targeted nanoparticles. A structure-based predictive model showed that only 4% of the drug space self-assembles with IR783. Here, we mapped the self-assembly outcomes of 77 small molecule drugs and drug pairs with IR783. We found that the small molecule drug space can be divided into five types, and type-1 drugs self-assemble with three out of four possible drug types that do not form stable nanoparticles. To predict the self-assembly outcome of any drug pair, we developed a machine learning model based on decision trees, which was trained and tested with F1-scores of 89.3% and 87.2%, respectively. We used literature text mining to capture drug pairs with biological synergy together with synergistic chemical self-assembly and generated a database with 1985 drug pairs for 70 cancers. We developed an online search tool to identify cancer-specific, meta-synergistic drug pairs (both chemical and biological synergism) and validated three different pairs in vitro. Lastly, we discovered a novel meta-synergistic pair, bortezomib-cabozantinib, which formed stable nanoparticles with improved biodistribution, efficacy, and reduced toxicity, even over single drugs, in an in vivo model of head and neck cancer.

Asymptomatic unilateral phrenic nerve palsy after bortezomib treatment in a newly diagnosed multiple myeloma patient

INTRODUCTION

Bortezomib is the first chemotherapeutic agent of proteosome inhibitor class that can be used in newly diagnosed and relapsed/refractory multiple myeloma. It is well known that bortezomib has side effects such as peripheral sensory, motor, or autonomic neuropathy. In this paper, we will present our patient who developed unilateral phrenic nerve palsy as an autonomic neuropathy after six cycles of subcutaneous bortezomib treatment. This case differs from other cases in that our patient was asymptomatic.

CASE REPORT

A 57-year-old male patient was admitted with back pain and gait disturbances. In the thorax computed tomography, a soft tissue mass causing compression on the spinal canal was observed in the T12 vertebra. Bone biopsy pathology report resulted in diffuse plasma cell infiltration. The patient was diagnosed with stage ISS-3, IgG kappa type multiple myeloma.

MANAGEMENT AND OUTCOME

Subcutaneous bortezomib 1 × 2.2 mg (Days 1-4-8-11) + intravenous cyclophosphamide 1000 mg (Day 1) + intravenous dexamethasone 40 mg (Days 1-2-3-4) (VCD chemotherapy protocol) was started. Totally six cycles of VCD were administered. While the patient did not have any respiratory symptoms, an elevation consistent with phrenic nerve palsy was observed in the left hemidiaphragm in the thorax computed tomography that was taken during the preparation for autologous hematopoietic stem cell transplantation.

DISCUSSION

Bortezomib is a frequently used chemotherapeutic agent in patients with multiple myeloma and care should be taken in terms of the risk of developing phrenic nerve palsy in patients. There are cases of autonomic neuropathy developing after bortezomib treatment.

Consolidation and maintenance therapy with bortezomib for Vietnamese patients with multiple myeloma after autologous transplantation

Thirty patients with newly diagnosed symtomatic MM (multiple myeloma) received ASCT (autologous stem cell transplantation) and two cycles of bortezomib-cyclophosphamide-dexamethasone as consolidation treatment followed by maintenance of bortezomib for 24 months. 16 patients achieved complete response (CR) after ASCT, and two more patients achieved CR after consolidation therapy. At 92 months of follow-up, the median OS was 69.5 months, the median PFS was 38.5 months. OS and PFS in the high-risk group were shorter than in the standard-risk group with a statistically significant difference (p = 0.028, 0.049; respectively). Post-ASCT consolidation and maintenance therapy using bortezomib were effective in patients with MM.

Inhibitors of the Mechanistic Target of Rapamycin Can Ameliorate Bortezomib-Induced Peripheral Neuropathy

Bortezomib, an anticancer drug for multiple myeloma and mantle cell lymphoma, causes severe adverse events and leads to peripheral neuropathy. The associated neuropathy limits the use of bortezomib and could lead to discontinuation of the treatment; therefore, effective intervention is crucial. In the present study, we statistically searched for a drug that could alleviate bortezomib-induced peripheral neuropathy using adverse event self-reports. We observed that specific inhibitors of the mechanistic target of rapamycin (mTOR) lowered the incidence of bortezomib-induced peripheral neuropathy. These findings were experimentally validated in mice, which exhibited long-lasting mechanical hypersensitivity after repeated bortezomib treatment. This effect was inhibited for hours after a systemic injection with rapamycin or everolimus in a dose-dependent manner. Bortezomib-induced allodynia was accompanied by the activation of spinal astrocytes, and intrathecal injection of mTOR inhibitors or an inhibitor of ribosomal protein S6 kinase 1, a downstream target of mTOR, exhibited considerable analgesic effects in a dose-dependent manner. These results suggest that mTOR inhibitors, which are readily available to patients prescribed bortezomib, are one of the most effective therapeutics for bortezomib-induced peripheral neuropathy.

Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating side effect of many common anti-cancer agents that can lead to dose reduction or treatment discontinuation, which decrease chemotherapy efficacy. Long-term CIPN can interfere with activities of daily living and diminish the quality of life. The mechanism of CIPN is not yet fully understood, and biomarkers are needed to identify patients at high risk and potential treatment targets. Metabolomics can capture the complex behavioral and pathophysiological processes involved in CIPN. This chapter is to review the CIPN metabolomics studies to find metabolic pathways potentially involved in CIPN. These potential CIPN metabolites are then investigated to determine whether there is evidence from studies of other neuropathy etiologies such as diabetic neuropathy and Leber hereditary optic neuropathy to support the importance of these pathways in peripheral neuropathy. Six potential biomarkers and their putative mechanisms in peripheral neuropathy were reviewed. Among these biomarkers, histidine and phenylalanine have clear roles in neurotransmission or neuroinflammation in peripheral neuropathy. Further research is needed to discover and validate CIPN metabolomics biomarkers in large clinical studies.

Genomic screening reveals ubiquitin-like modifier activating enzyme 1 as a potent and druggable target in c-MYC-high triple negative breast cancer models

Triple negative breast cancer (TNBC) accounts for over 30% of all breast cancer (BC)-related deaths, despite accounting for only 10% to 15% of total BC cases. Targeted therapy development has largely stalled in TNBC, underlined by a lack of traditionally druggable addictions like receptor tyrosine kinases (RTKs). Here, through full genome CRISPR/Cas9 screening of TNBC models, we have uncovered the sensitivity of TNBCs to the depletion of the ubiquitin-like modifier activating enzyme 1 (UBA1). Targeting UBA1 with the first-in-class UBA1 inhibitor TAK-243 induced unresolvable endoplasmic reticulum (ER)-stress and activating transcription factor 4 (ATF4)-mediated upregulation of proapoptotic NOXA, leading to cell death. c-MYC expression correlates with TAK-243 sensitivity and cooperates with TAK-243 to induce a stress response and cell death. Importantly, there was an order of magnitude greater sensitivity of TNBC lines to TAK-243 compared to normal tissue-derived cells. In five patient derived xenograft models (PDXs) of TNBC, TAK-243 therapy led to tumor inhibition or frank tumor regression. Moreover, in an intracardiac metastatic model of TNBC, TAK-243 markedly reduced metastatic burden, indicating UBA1 is a potential new target in TNBC expressing high levels of c-MYC.

Refractory postherpetic neuralgia in a multiple myeloma patient with lenalidomide maintenance therapy: a case report

Herpes zoster is not common in multiple myeloma (MM) patients treated with lenalidomide-based regimens. We report an MM patient in his late 60s who received lenalidomide as maintenance treatment and whose condition was complicated with refractory postherpetic neuralgia. The patient received antiviral treatment and analgesia immediately after the diagnosis of herpes zoster. Two months later, the patient received acupuncture, radiofrequency treatment, and even spinal cord stimulation, which failed to relieve the pain. Consequently, we performed high-resolution magnetic resonance imaging of the cervical and thoracic nerves. Then, stellate ganglion block, left C5/C6/C7/C8 nerve root block, and left thoracic 1, 2 paravertebral nerve block were performed with the assistance of real-time ultrasound. The pain was immediately relieved after treatment; however, the symptoms reappeared 2 days later. At 5 months after treatment, the patient still experienced severe pain. We suggest that MM patients complicated with postherpetic neuralgia are refractory to treatment. Starting nerve block therapy, pulsed radiofrequency, and other interventional therapies as early as possible could be a more optimal treatment plan for these patients.

Mechanistic involvement of inflammation in bortezomib induced peripheral neuropathy

AIM

To establish the role of inflammation in bortezomib induced peripheral neuropathy (BIPN).

BACKGROUND

Peripheral neuropathy is the dose-limiting toxicity of bortezomib which can lead to discontinuation of the treatment. There are multiple mechanisms involved in the disposition of BIPN. However, the role of inflammatory mediators is still under investigation. The complete understanding of inflammatory markers in relation to BIPN can lead to the development of effective therapy for prophylaxis and treatment of peripheral neuropathy.

OBJECTIVE

Based on the available data, postulate the role of inflammatory mediators in the development of peripheral neuropathy due to bortezomib.

METHOD

The "Pubmed" and "Google Scholar" were used as the search engines with terms like "peripheral neuropathy", "bortezomib induced peripheral neuropathy" and "inflammation". Original research, case reports and review articles were considered.

RESULTS

Bortezomib use is associated with the development of peripheral neuropathy. This effect is due to the damage to Schwann cells and dorsal root ganglion neurons; mitochondrial damage; increased ion channel susceptibility; and higher infiltration of macrophages in the spinal cord. All these factors collectively increase the secretion of inflammatory mediators and lead to the development of neuropathic pain.

CONCLUSION

Targeting inflammatory mediators may be helpful in the treatment of bortezomib-induced peripheral neuropathy.

Update on Toxic Neuropathies

Purpose of Review

Toxic neuropathies are an important preventable and treatable form of peripheral neuropathy. While many forms of toxic neuropathies have been recognized for decades, an updated review is provided to increase vigilant in this area of neurology. A literature review was conducted to gather recent information about toxic neuropathies, which included the causes, clinical findings, and treatment options in these conditions.

Recent Findings

Toxic neuropathies continue to cause significant morbidity throughout the world and the causative agents, particularly with regards to medications, do not appear to be diminishing. A wide variety of causes of toxic neuropathies exist, which include alcohol, industrial chemicals, biotoxins, and medications. Unfortunately, no breakthrough treatments have been developed and prevention and symptom management remain the standard of care.

Summary

A detailed medication, occupational and hobby exposure history is critical to identifying toxic neuropathies. Increased research is warranted to identify mechanisms of neurotoxic susceptibility and potential common pathomechanistic pathways for treatment across diverse toxic neuropathies.

Bortezomib-Induced Epigenetic Alterations in Nerve Cells: Focus on the Mechanisms Contributing to the Peripheral Neuropathy Development

Bortezomib-induced peripheral neuropathy (BiPN) occurs in approximately 40% of patients with multiple myeloma. The induction of severe neuropathy entails the dose reduction or complete elimination of bortezomib (BTZ). Interestingly, discontinuation of BTZ mostly results in a reduction or complete resolution of peripheral neuropathy (PN) symptoms. Therefore, it is likely that the BiPN mechanisms are based on temporary/reversible changes such as epigenetic alterations. In this study, we examined the effect of treating nerve cells, differentiated from the Lund human mesencephalic (dLUHMES) cell line, with several low-dose BTZ (0.15 nM) applications. We showed a significant decrease in global histone H3 acetylation as well as histone H3 lysine 9 acetylation. Moreover, analysis of the genetic microarray showed changes mainly in epigenetic processes related to chromatin rearrangement, chromatin silencing, and gene silencing. GSEA analysis revealed three interesting signaling pathways (SIRT1, B-WICH and, b-Catenin) that may play a pivotal role in PN development. We also performed an analysis of the miRNA microarray which showed the interactions of miR-6810-5p with the genes MSN, FOXM1, TSPAN9, and SLC1A5, which are directly involved in neuroprotective processes, neuronal differentiation, and signal transduction. The study confirmed the existence of BTZ-induced complex epigenetic alterations in nerve cells. However, further studies are necessary to assess the reversibility of epigenetic changes and their potential impact on the induction/resolution of PN.

Prevention of Bortezomib-Induced Peripheral Neuropathy in Newly Multiple Myeloma Patients Using Nervonic Acid, Curcuma Rizoma, and L-Arginine Compound: A Pilot Study

INTRODUCTION

This is a phase II pilot study to evaluate the efficacy of a nutraceutical compound composed of nervonic acid, curcuma rizoma, and l-Arginine to prevent the onset of bortezomib-induced peripheral neuropathy (BIPN) in 16 newly diagnosed multiple myeloma (MM) patients treated with bortezomib (BTZ) over 6 months.

MATERIALS AND METHODS

Assessments included neurological examination and electroneurography, Common Terminology Criteria for Adverse Events (NCI-CTCAE), reduced version of Total Neuropathic Score (TNSr), pain evaluation, functional autonomy scales, self-perceived symptoms and quality of life questionnaires at baseline and after 6 months.

RESULTS

No patients were symptomatic at baseline, despite neurophysiological data and TNSr evidence of peripheral neuropathy (PN) in 11 of them. After 6 months, only 9 patients completed the study. All had modifications in neurological examination with 8 out of 9 showing neurophysiological data of PN (2 of which had a NCI-CTCAE grade of neurotoxicity ≥2); 4 patients dropped out due to BIPN, 2 because of MM progression, 1 for scarce compliance.

DISCUSSION

In our study, the compound was not adequate to prevent BIPN. The incidence of subclinical PN in MM patients is a risk factor for the development of severe neurotoxicity during BTZ treatment. For this reason to evaluate the efficacy of any preventive compound, as well as to manage MM patients, it should be mandatory to include neurophysiological study as a standard procedure.

Chemotherapy-Induced Peripheral Neuropathy: Epidemiology, Pathomechanisms and Treatment

PURPOSE

This review provides an update on the current clinical, epidemiological and pathophysiological evidence alongside the diagnostic, prevention and treatment approach to chemotherapy-induced peripheral neuropathy (CIPN).

FINDINGS

The incidence of cancer and long-term survival after treatment is increasing. CIPN affects sensory, motor and autonomic nerves and is one of the most common adverse events caused by chemotherapeutic agents, which in severe cases leads to dose reduction or treatment cessation, with increased mortality. The primary classes of chemotherapeutic agents associated with CIPN are platinum-based drugs, taxanes, vinca alkaloids, bortezomib and thalidomide. Platinum agents are the most neurotoxic, with oxaliplatin causing the highest prevalence of CIPN. CIPN can progress from acute to chronic, may deteriorate even after treatment cessation (a phenomenon known as coasting) or only partially attenuate. Different chemotherapeutic agents share both similarities and key differences in pathophysiology and clinical presentation. The diagnosis of CIPN relies heavily on identifying symptoms, with limited objective diagnostic approaches targeting the class of affected nerve fibres. Studies have consistently failed to identify at-risk cohorts, and there are no proven strategies or interventions to prevent or limit the development of CIPN. Furthermore, multiple treatments developed to relieve symptoms and to modify the underlying disease in CIPN have failed.

IMPLICATIONS

The increasing prevalence of CIPN demands an objective approach to identify at-risk patients in order to prevent or limit progression and effectively alleviate the symptoms associated with CIPN. An evidence base for novel targets and both pharmacological and non-pharmacological treatments is beginning to emerge and has been recognised recently in publications by the American Society of Clinical Oncology and analgesic trial design expert groups such as ACTTION.

Foot drop in patients treated with bortezomib - a case series and review of the literature

Bortezomib-induced peripheral neuropathy (BIPN) has a profound impact on quality of life, which is an important issue considering the growing number of survivors of multiple myeloma and amyloidosis. BIPN is typically symmetric, distal, "stocking and glove" distribution and predominantly consists of sensory rather than motor symptoms. In this case series, we report an acute neurotoxicity syndrome induced by bortezomib, which is clinically distinct from BIPN by not being peripheral and distal. We describe six patients that developed unilateral or bilateral foot drop attributed to bortezomib. With bortezomib discontinuation symptoms improved gradually over months to years.

Proteasome Activity in the Plasma as a Novel Biomarker in Mild Cognitive Impairment with Chronic Tinnitus

BACKGROUND

Although the existence of proteasomes in human blood, termed circulating proteasomes (c-proteasomes), has been reported previously, their origin and pathophysiological functions remain largely unknown.

OBJECTIVE

Given that c-proteasome activity was significantly reduced in Alzheimer's disease model mice and relatively high frequency of mild cognitive impairment (MCI) is accompanied by chronic tinnitus in aged patients, we examined whether c-proteasome activity in human plasma was associated with cognitive function in patients with chronic tinnitus.

METHODS

c-Proteasome activity in the plasma of tinnitus patients (N = 55) was measured with fluorogenic reporter substrate, suc-LLVY-AMC. To assess MCI, the Montreal Cognitive Assessment was conducted with a cut-off score of 22/23. All patients underwent audiological and psychoacoustic analyses. Levels of c-proteasomes, Aβ42, and Aβ40 were measured using ELISA, and their association with c-proteasome activity was evaluated.

RESULTS

The activity of circulating proteasomes was significantly lower in patients with chronic tinnitus and MCI (p = 0.042), whereas activities of other plasma enzymes showed little correlation. In addition, c-proteasome activity was negatively associated with the level of plasma Aβ and was directly dependent on its own concentration in the plasma of patients with chronic tinnitus.

CONCLUSION

Our current work provides a new perspective for understanding the potential relationship between circulating proteasomes in the plasma and cognitive dysfunction, suggesting a novel, non-invasive biomarker in the context of MCI diagnosis.

Targeted Therapy in the Treatment of Pediatric Acute Lymphoblastic Leukemia-Therapy and Toxicity Mechanisms

Targeted therapy has revolutionized the treatment of poor-prognosis pediatric acute lymphoblastic leukemia (ALL) with specific genetic abnormalities. It is still being described as a new landmark therapeutic approach. The main purpose of the use of molecularly targeted drugs and immunotherapy in the treatment of ALL is to improve the treatment outcomes and reduce the doses of conventional chemotherapy, while maintaining the effectiveness of the therapy. Despite promising treatment results, there is limited clinical research on the effect of target cell therapy on the potential toxic events in children and adolescents. The recent development of highly specific molecular methods has led to an improvement in the identification of numerous unique expression profiles of acute lymphoblastic leukemia. The detection of specific genetic mutations determines patients’ risk groups, which allows for patient stratification and for an adjustment of the directed and personalized target therapies that are focused on particular molecular alteration. This review summarizes the knowledge concerning the toxicity of molecular-targeted drugs and immunotherapies applied in childhood ALL.

Redox-sensitive TRP channels: a promising pharmacological target in chemotherapy-induced peripheral neuropathy

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) and its related pain is a major side effect of certain chemotherapeutic agents used in cancer treatment. Available analgesics are mostly symptomatic, and on prolonged treatment, patients become refractive to them. Hence, the development of improved therapeutics that act on novel therapeutic targets is necessary. Potential targets include the redox-sensitive TRP channels [e.g. TRPA1, TRPC5, TRPC6, TRPM2, TRPM8, TRPV1, TRPV2, and TRPV4] which are activated under oxidative stress associated with CIPN.

AREAS COVERED

We have examined numerous neuropathy-inducing cancer chemotherapeutics and their pathophysiological mechanisms. Oxidative stress and its downstream targets, the redox-sensitive TRP channels, together with their potential pharmacological modulators, are discussed. Finally, we reflect upon the barriers to getting new therapeutic approaches into the clinic. The literature search was conducted in PubMed upto and including April 2021.

EXPERT OPINION

Redox-sensitive TRP channels are a promising target in CIPN. Pharmacological modulators of these channels have reduced pain in preclinical models and in clinical studies. Clinical scrutiny suggests that TRPA1, TRPM8, and TRPV1 are the most promising targets because of their pain-relieving potential. In addition to the analgesic effect, TRPV1 agonist-Capsaicin possesses a disease-modifying effect in CIPN through its restorative property in damaged sensory nerves.

Management of Myeloma Manifestations and Complications: The Cornerstone of Supportive Care: Recommendation of the Canadian Myeloma Research Group (formerly Myeloma Canada Research Network) Consensus Guideline Consortium

Multiple myeloma (MM) is a hematological cancer associated with significant symptomatic burden. Bone disease, renal insufficiency, cytopenias, infection, and peripheral neuropathy, among other disease manifestations and complications, impair patients' quality of life. The Canadian Myeloma Research Group Consensus Guideline Consortium, formerly Myeloma Canada Research Network Consensus Guideline Consortium, proposes national consensus recommendations for the management of MM-related manifestations and complications. To address the needs of Canadian physicians and people living with MM across the country, this document focuses on the improvement and maintenance of patient care by clarifying best-practice approaches for the prevention, detection and management of disease manifestations and complications. The Canadian Myeloma Research Group Consensus Guideline Consortium will periodically review the recommendations herein and update as necessary.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

A phase II trial of continuous ixazomib, thalidomide and dexamethasone for relapsed and/or refractory multiple myeloma: the Australasian Myeloma Research Consortium (AMaRC) 16-02 trial

We evaluated the efficacy and tolerability of continuous ixazomib-thalidomide-dexamethasone (ITd: 4 mg, day 1, 8, 15; 100 mg daily; and 40 mg weekly). A total of 39 patients with relapsed/refractory multiple myeloma (RRMM) aged ≥18 years with one to three prior lines of therapy were enrolled from two tertiary centres in Victoria and South Australia, Australia. The overall response rate (ORR) was 56·4% with a clinical benefit rate of 71·8%. The median progression-free survival was 13·8 months [95% confidence interval (CI) 8·2-22·2] and median overall survival was not reached. The median time to best response and duration of response was 3·7 months (95% CI 2·8-10·5) and 18·4 months (95% CI 10·2-31·0) respectively. Prior immunomodulatory drug (IMID) exposure was associated with a lower ORR (40% vs. 73·7%, P = 0·03). Survival outcomes in patients with prior proteasome inhibitor (PI) and/or IMID exposure were similar. Patients received a median (range) of 11 (1-31) cycles of therapy and six patients (15%) remained on therapy at the time of final analysis. Grade 3/4 haematological and non-haematological adverse events were reported in 7·7% and 20·6% of patients respectively. ITd dose reductions were required in 15·4%, 48·7% and 35·9% of patients respectively. The present study demonstrates promising effectiveness and tolerability of ITd as an affordable all-oral PI-IMID approach for RRMM.

Cytotoxicity and Target Modulation in Pediatric Solid Tumors by the Proteasome Inhibitor Carfilzomib

BACKGROUND

Most children with recurrent metastatic solid tumors have high mortality rates. Recent studies have shown that proteasome inhibition leads to effective tumor killing in cells that have acquired treatment resistance and metastatic properties.

OBJECTIVE

The purpose of this study was to test the potential of Carfilzomib (CFZ), a proteasome inhibitor, in refractory pediatric solid tumors, which is currently unknown.

METHODS

A panel of pediatric solid tumor cell lines, including neuroblastoma, Ewing's sarcoma, osteosarcoma, rhabdomyosarcoma, and atypical teratoid rhabdoid tumor (ATRT), was used to evaluate the cytotoxic and proteasomal inhibitory effects of CFZ. A drug scheduling experiment was performed to determine the optimal dose and time to obtain effective cell killing. Combination studies of CFZ with chemotherapeutic drugs of different classes were performed to determine the extent of synergy.

RESULTS

CFZ showed effective cytotoxicity against all cell lines tested (mean IC50 = 7nM, range = 1-20nM) and activity in a fluorophore-tagged cell-based proteasome assay. Drug scheduling experiments showed that the minimum exposure of 4-8 hours/day is needed for effective cumulative killing. CFZ, when combined with chemotherapeutic drugs of different classes, synergistically enhanced the extent of cell death.

CONCLUSIONS

CFZ showed cytotoxic activity against all the solid pediatric cancer cell lines tested. This study provides initial in vitro data on the potential of CFZ to treat pediatric solid tumors and supports further investigations into the components of drug scheduling, biological correlates, and drug combinations for future early phase clinical trials in children.

Design, synthesis and biological evaluation of dipeptides as novel non-covalent 20S proteasome inhibitors

Based on the interaction modes of the natural 20S proteasome inhibitors TMC-95A, we have previously discovered a dipeptide 1. To explore the SAR around compound 1, we designed and synthesized a series of dipeptides (8-38) with a fragment-based strategy. Among them, nine compounds showed significant inhibitory activities against the chymotrypsin-like activity of human 20S proteasome with IC₅₀ values at the submicromolar level, which were comparable or even superior to the parent compound 1. Meanwhile, they displayed no significant inhibition against trypsin-like and caspase-like activities of 20S proteasome. The results suggested the feasibility to design dipeptides as novel and potent 20S proteasome inhibitors.[Formula: see text].

The proteasome and its role in the nervous system

Proteasomes are multisubunit complexes that catalyze the majority of protein degradation in mammalian cells to maintain protein homeostasis and influence the regulation of most cellular processes. The proteasome, a multicatalytic protease complex, is a ring-like structure with a narrow pore that exhibits regulated gating, enabling the selective degradation of target proteins into peptide fragments. This process of removing proteins is essential for eliminating proteins that are no longer wanted, such as unfolded or aggregated proteins. This is important for preserving cellular function relevant to brain health and disease. Recently, in the nervous system, specialized proteasomes have been shown to generate peptides with important cellular functions. These discoveries challenge the prevailing notion that proteasomes primarily operate to eliminate proteins and identify signaling-competent proteasomes. This review focuses on the structure, function, and regulation of proteasomes and sheds light on emerging areas of investigation regarding the role of proteasomes in the nervous system.

Connecting TDP-43 Pathology with Neuropathy

Transactive response DNA-binding protein 43 kDa (TDP-43), a multifunctional nucleic acid-binding protein, is a primary component of insoluble aggregates associated with several devastating nervous system disorders; mutations in TARDBP, its encoding gene, are a cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here, we review established and emerging roles of TDP-43 and consider how its dysfunction impinges on RNA homeostasis in the nervous system, thereby contributing to neural degeneration. Notably, improper splicing of the axonal growth-associated factor STMN2 has recently been connected to TDP-43 dysfunction, providing a mechanistic link between TDP-43 proteinopathies and neuropathy. This review highlights how a deep understanding of the function of TDP-43 in the brain might be leveraged to develop new targeted therapies for several neurological disorders.

Peripheral Neuropathy under Oncologic Therapies: A Literature Review on Pathogenetic Mechanisms

Peripheral neurologic complications are frequent adverse events during oncologic treatments and often lead to dose reduction, administration delays with time elongation of the therapeutic plan and, not least, worsening of patients’ quality of life. Experience skills are required to recognize symptoms and clinical evidences and the collaboration between different health professionals, in particular oncologists and hospital pharmacists, grants a correct management of this undesirable occurrence. Some classes of drugs (platinates, vinca alkaloids, taxanes) typically develop this kind of side effect, but the genesis of chemotherapy-induced peripheral neuropathy is not linked to a single mechanism. This paper aims from one side at summarizing and explaining all the scattering mechanisms of chemotherapy-induced peripheral neuropathy through a detailed literature revision, on the other side at finding new approaches to possible treatments, in order to facilitate the collaboration between oncologists, hematologists and hospital pharmacists.

Pathological Mechanisms of Bortezomib-Induced Peripheral Neuropathy

Bortezomib, a first-generation proteasome inhibitor widely used in chemotherapy for hematologic malignancy, has effective anti-cancer activity but often causes severe peripheral neuropathy. Although bortezomib-induced peripheral neuropathy (BIPN) is a dose-limiting toxicity, there are no recommended therapeutics for its prevention or treatment. One of the most critical problems is a lack of knowledge about pathological mechanisms of BIPN. Here, we summarize the known mechanisms of BIPN based on preclinical evidence, including morphological abnormalities, involvement of non-neuronal cells, oxidative stress, and alterations of transcriptional programs in both the peripheral and central nervous systems. Moreover, we describe the necessity of advancing studies that identify the potential efficacy of approved drugs on the basis of pathological mechanisms, as this is a convincing strategy for rapid translation to patients with cancer and BIPN.

Comparing neuropathy in multiple myeloma and AL amyloidosis

Peripheral neuropathy (PN) is frequent in patients with monoclonal gammopathy due to plasma cell dyscrasia, but little is known about the comparative impact of nerve dysfunction in different disorders. We compared clinical and laboratory results between two diagnostic groups. We recruited 76 untreated multiple myeloma (MM) and 27 AL amyloidosis (ALA) patients for evaluation of symptoms, clinical findings and nerve conduction studies (NCS). We diagnosed significant PN using total neuropathy scores (TNS > 7) in 17.6% of MM and 48.1% of ALA patients and in 27.7% of MM and 35.7% of ALA patients using NCS findings. TNS score grades were significantly higher in the AL amyloidosis patients (Fisher's exact test: P = .02) but a NCS based PN diagnosis was not significantly different (Fisher's exact test: P = .13). A significantly higher TNS vibration (P = .04) and pin (P = .02) sensory sign and TNS reflex (P = .04) sign score was found in amyloidosis patients. Likewise, quantitative sensory thresholds for vibration was higher in amyloidosis patients (Welsh ANOVA: P = .01). NCS revealed signs of more frequent axonal tibial neuropathy with significantly lower motor response amplitudes (P = .02) and resulting higher TNS scores (P = .002), while sural nerve sensory response amplitudes were without significant difference (P = .86). We found more severe TNS grades of PN in AL amyloidosis patients compared with MM patients. We also found higher sensory symptoms scores and higher thresholds for vibration but similar sensory involvement using NCS. The NCS exclusively showed signs of an axonal neuropathy.

Clinical manifestations of intravitreal bortezomib injection

Purpose

To describe the clinical presentation and ocular manifestations of intravitreal bortezomib.

Observations

Retrospective chart review of five patients who inadvertently received intravitreal injection of bortezomib, instead of bevacizumab, showed that all patients presented hyperacutely within 24–72 hours of the injection with pain and severe vision loss. Examination revealed a fibrinous anterior uveitis, corneal edema, and choroidal effusion associated with a shallow anterior chamber and secondary angle closure glaucoma. Significant vitritis was notably absent. Severe retinal vascular attenuation and optic atrophy, and sometimes even retinal infarction or detachment, followed. Four of the five patients rapidly progressed to no light perception vision. Vitreous gram stain and cultures were negative in all eyes.

Conclusions and importance

Intravitreal bortezomib is severely toxic to the eye. Special safeguards should be instituted for the dispensing of intravitreal medications.

Chemotherapy-Induced Peripheral Neuropathy and its Impact on Health-Related Quality of Life among Multiple Myeloma Patients: A Single-Center Experience

Aim

Chemotherapy-induced peripheral neuropathy (CIPN) is a long-term neurological health issue in patients diagnosed with multiple myeloma (MM). The aim of this study was to assess CIPN symptoms and health-related quality of life (HRQOL) among MM patients.

Methods

A cross-sectional survey was conducted among patients diagnosed with MM in a tertiary care hospital using a self-reported Arabic questionnaire, European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire for CIPN scale (QLQ-CIPN20). The HRQOL was assessed using EORTC multiple myeloma module (QLQ-MY20). Categorical variables were reported in frequency tables and percentages. Age and duration of MM diagnosis were reported as mean and standard deviation. Survey responses were presented using descriptive statistics.

Results

In total, 62 patients had participated. Males were 60%. The average age was 58.74 ± 11.49 years. On sensory scale, 20% reported "quite a bit"/"very much" tingling in fingers/hands, 23% in toes/feet, 39% numbness in fingers/hands, 37% in toes/feet, and 43% reported trouble standing or walking. On motor scale, 40% reported trouble walking and 60% had difficulty in climbing stairs/standing up from chair. On autonomic scale, 27% reported orthostatic hypotension and only 13/37 (46%) males reported erectile dysfunction. For HRQOL, 50% reported bone aches/pain, 42% reported back pain, 57% reported feeling ill, 33% reported lost hair, 35% had been thinking about their illness, whereas 28% were worried about future health and 22% had reported being worried about dying.

Conclusion

MM patients encounter CIPN symptoms with impaired HRQOL. Capturing CIPN as a patient-reported outcome needs to be considered in routine clinical practice.

Non-Hematologic Toxicity of Bortezomib in Multiple Myeloma: The Neuromuscular and Cardiovascular Adverse Effects

Simple Summary

Multiple myeloma (MM) is a still uncurable tumor of mainly elderly patients originating from the terminally differentiated B cells. Introduction to the treatment of MM patients of a new class of drugs called proteasome inhibitors (bortezomib followed by carfilzomib and ixazomib) significantly improved disease control. Proteasome inhibitors interfere with the major mechanism of protein degradation in a cell leading to the severe imbalance in the protein turnover that is deadly to MM cells. Currently, these drugs are the mainstream of MM therapy but are also associated with an increased rate of the injuries to multiple organs and tissues. In this review, we summarize the current knowledge on the molecular mechanisms of the first-in-class proteasome inhibitor bortezomib-induced disturbances in the function of peripheral nerves and cardiac and skeletal muscle.

Abstract

The overall approach to the treatment of multiple myeloma (MM) has undergone several changes during the past decade. and proteasome inhibitors (PIs) including bortezomib, carfilzomib, and ixazomib have considerably improved the outcomes in affected patients. The first-in-class selective PI bortezomib has been initially approved for the refractory forms of the disease but has now become, in combination with other drugs, the backbone of the frontline therapy for newly diagnosed MM patients, as well as in the maintenance therapy and relapsed/refractory setting. Despite being among the most widely used and highly effective agents for MM, bortezomib can induce adverse events that potentially lead to early discontinuation of the therapy with negative effects on the quality of life and outcome of the patients. Although peripheral neuropathy and myelosuppression have been recognized as the most relevant bortezomib-related adverse effects, cardiac and skeletal muscle toxicities are relatively common in MM treated patients, but they have received much less attention. Here we review the neuromuscular and cardiovascular side effects of bortezomib. focusing on the molecular mechanisms underlying its toxicity. We also discuss our preliminary data on the effects of bortezomib on skeletal muscle tissue in mice receiving the drug.

Priming the Proteasome to Protect against Proteotoxicity

Increased proteotoxic stress (IPTS) resulting from the increased production or decreased removal of abnormally folded proteins is recognized as an important pathogenic factor for a large group of highly disabling and life-threatening human diseases, such as neurodegenerative disorders and many heart diseases. The proteasome is pivotal to the timely removal of abnormal proteins but its functional capacity often becomes inadequate in the disease conditions; consequently, proteasome functional insufficiency in return exacerbates IPTS. Recent research in proteasome biology reveals that the proteasome can be activated by endogenous protein kinases, making it possible to pharmacologically prime the proteasome for treating diseases with IPTS.

Serum brain-derived neurotrophic factor (BDNF) concentration predicts polyneuropathy and overall survival in multiple myeloma patients

Brain-derived neurotrophic factor (BDNF) is a protein with a potent influence on several aspects of neuronal and blood vessel functions. However, its prognostic potential and functional role in multiple myeloma (MM) remain largely unknown. In this study, we investigated the influence of BDNF on the risk of chemotherapy-induced peripheral neuropathy (CIPN) and clinical outcome. Study group consisted of 91 newly-diagnosed MM patients treated with bortezomib and/or thalidomide-based chemotherapy. Detection of BDNF in serum was performed using ELISA. Polyneuropathy was assessed according to the CTCAE Criteria v5. We observed that BDNF concentration correlated with the severity of polyneuropathy (P = 0·0463). Higher BDNF values were noted in patients who responded to treatment (P = 0·0326), and BDNF proved to be a useful marker to predict lack of response after eight cycles of treatment (sensitivity - 100%, specificity - 61·5%, P = 0·0142). Moreover this marker showed significant diagnostic usefulness in diagnosis of CIPN (sensitivity - 76%, specificity - 71·43%; area under the curve (AUC)= 0·77, 95%, confidence interval (CI): 0·64-0·88; P < 0·0001). Low BDNF was an independent, unfavourable prognostic factor associated with reduced overall survival (OS) (hazard ratio (HR) = 2·79, P = 0·0470). In conclusion, BDNF level may play a prognostic role and constitute a useful biomarker in predicting CIPN in MM patients.

GATA3-dependent epigenetic upregulation of CCL21 is involved in the development of neuropathic pain induced by bortezomib

The incidence of bortezomib-induced neuropathic pain hampers the progress of therapy for neoplasia and also negatively affects the quality of life of patients. However, the molecular mechanism underlying bortezomib-induced neuropathic pain remains unknown. In this study, we found that the application of bortezomib significantly increased the expression of GATA-binding protein 3 (GATA3) in the spinal dorsal horn, and intrathecal administration of GATA3 siRNA attenuated mechanical allodynia. Furthermore, chromatin immunoprecipitation sequencing showed that bortezomib treatment induced the redistribution of GATA3 to transcriptional relevant regions. Notably, combined with the results of mRNA microarray, we found that C–C motif chemokine ligand 21 (CCL21) had an increased GATA3 binding and upregulated mRNA expression in the dorsal horn after bortezomib treatment. Next, we found that bortezomib treatment induced CCL21 upregulation in the spinal neurons, which was significantly reduced upon GATA3 silencing. Blockade of CCL21 using the neutralizing antibody or special siRNA ameliorated mechanical allodynia induced by bortezomib. In addition, bortezomib treatment increased the acetylation of histone H3 and the interaction between GATA3 and CREB-binding protein. GATA3 siRNA suppressed the CCL21 upregulation by decreasing the acetylation of histone H3. Together, these results suggested that activation of GATA3 mediated the epigenetic upregulation of CCL21 in dorsal horn neurons, which contributed to the bortezomib-induced neuropathic pain.