Ixazomib: an investigational drug for the treatment of lymphoproliferative disorders

Ixazomib Combined With Autologous Stem Cell Transplantation for POEMS Syndrome: A Case Report and Meta-Analysis

Objective: Polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes (POEMS) syndrome is a rare monoclonal plasma cell proliferation disorder. At present, there is no unified treatment for POEMS syndrome. Here, we describe one case with POEMS syndrome with obvious neurological symptoms diagnosed in September 2020. We made a meta--analysis to assess the efficacy of treatment strategies in recent years. Methods: We retrospectively analyzed the diagnosis and treatment of this patient, and searched relevant articles in PubMed, Embase, and MEDLINE databases using MedicalSubject Headings (MeSH) (eg, POEMS, Therapy, Drug Therapy, Biological Therapy, Combined Modality Therapy, Hematopoietic Stem Cell Transplantation, Immunotherapy, Molecular Targeted Therapy, Chemoradiotherapy, and Salvage Therapy) and free words, and performed the statistical analysis. Results: The patient's efficacy evaluation was complete response (CR) after treatment with ixazomib combined with autologous stem cell transplantation (ASCT). Overall, 20 articles consist of 6 clinical trials, 14 retrospective studies, and 936 patients were included in this meta-analysis. There was no significant difference in complete hematologic response (CR_H) rate between people who underwent ASCT and those who did not. However, ASCT might have a better survival rate. Conclusions: Ixazomib combined with ASCT therapy may be a safe and effective method for patients with POEMS syndrome.

Advances in covalent drug discovery

Covalent drugs have been used to treat diseases for more than a century, but tools that facilitate the rational design of covalent drugs have emerged more recently. The purposeful addition of reactive functional groups to existing ligands can enable potent and selective inhibition of target proteins, as demonstrated by the covalent epidermal growth factor receptor (EGFR) and Bruton's tyrosine kinase (BTK) inhibitors used to treat various cancers. Moreover, the identification of covalent ligands through 'electrophile-first' approaches has also led to the discovery of covalent drugs, such as covalent inhibitors for KRAS(G12C) and SARS-CoV-2 main protease. In particular, the discovery of KRAS(G12C) inhibitors validates the use of covalent screening technologies, which have become more powerful and widespread over the past decade. Chemoproteomics platforms have emerged to complement covalent ligand screening and assist in ligand discovery, selectivity profiling and target identification. This Review showcases covalent drug discovery milestones with emphasis on the lessons learned from these programmes and how an evolving toolbox of covalent drug discovery techniques facilitates success in this field.

Dietary Flavonoids with Catechol Moiety Inhibit Anticancer Action of Bortezomib: What about the other Boronic Acid-Based Drugs?

Approval of the first boronic acid group-containing drug, bortezomib, in 2003 for the treatment of multiple myeloma sparked an increased interest of medicinal chemists in boronic acid-based therapeutics. As a result, another boronic acid moiety-harboring medication, ixazomib, was approved in 2015 as a second-generation proteasome inhibitor for multiple myeloma; and dutogliptin is under clinical investigation in combination therapy against myocardial infarction. Moreover, a large number of novel agents with boronic acid element in their structure are currently in intensive preclinical studies, allowing to suppose that at least some of them enter clinical trials in the near future. On the other hand, only some years after bortezomib approval, direct interactions between its boronic acid group and catechol moiety of green tea catechins as well as some other common dietary flavonoids like quercetin and myricetin were discovered, leading to the formation of stable cyclic boronate esters and abolishing the anticancer activities. Although highly relevant, to date, no reports on possible co-effects of catechol group-containing flavonoids with new-generation boronic acid-based drugs can be found. However, this issue cannot be ignored, especially considering the abundance of catechol moiety-harboring flavonoids in both plant-derived food items as well as over-the-counter dietary supplements and herbal products. Therefore, in parallel with the intensified development of boronic acid-based drugs, their possible interactions with catechol groups of plant-derived flavonoids must also be clarified to provide dietary recommendations to patients for maximizing therapeutic benefits. If concurrently consumed flavonoids can indeed antagonize drug efficacy, it may pose a real risk to clinical outcomes.

Ixazomib, lenalidomide, and dexamethasone combination in "real-world" clinical practice in patients with relapsed/refractory multiple myeloma

Ixazomib is approved for use in combination with lenalidomide and dexamethasone (IRd) for patients with multiple myeloma (MM) who received at least one previous therapy. Registration study "TOURMALINE MM-1" was published in 2016. Nevertheless, clinical trials are significantly different from real-world use. From June 2016 to December 2018, IRd was available for Slovak patients with relapsed/refractory MM through a Named Patient Program. The aim of this study was to evaluate the efficacy and safety of ixazomib. We analyzed in this cohort study outcomes of 106 MM patients treated with IRd at 2 academic centers. The median age at diagnosis was 63 years (44-78). The median number of prior lines was 2 (1-7). The majority had high international staging system (ISS) score: 18, 29, and 59 were in the ISS I, ISS II, and ISS III groups, respectively. Treatment continued until progression, unacceptable toxicity, or death. The median follow-up for the entire cohort was 29 (0-49) months. The overall response rate was 74.5% (complete remission, 7.5%; partial remission, 67%). The median overall survival was not reached. Median progression-free survival (PFS) was 43 months (95% CI 35.6-50.4). The Kaplan-Meier method was used to generate survival curves, and we compared the influence of different factors on PFS. The most common hematological adverse events of any grade were neutropenia (90.4%), anemia (55.6%), and thrombocytopenia (43.4%). Our real-world data support the use of IRd as a highly effective and well-tolerated oral treatment protocol for relapsed myeloma.

Pre-Clinical Evaluation of the Proteasome Inhibitor Ixazomib against Bortezomib-Resistant Leukemia Cells and Primary Acute Leukemia Cells

At present, 20-30% of children with acute leukemia still relapse from current chemotherapy protocols, underscoring the unmet need for new treatment options, such as proteasome inhibition. Ixazomib (IXA) is an orally available proteasome inhibitor, with an improved safety profile compared to Bortezomib (BTZ). The mechanism of action (proteasome subunit inhibition, apoptosis induction) and growth inhibitory potential of IXA vs. BTZ were tested in vitro in human (BTZ-resistant) leukemia cell lines. Ex vivo activity of IXA vs. BTZ was analyzed in 15 acute lymphoblastic leukemia (ALL) and 9 acute myeloid leukemia (AML) primary pediatric patient samples. BTZ demonstrated more potent inhibitory effects on constitutive β5 and immunoproteasome β5i proteasome subunit activity; however, IXA more potently inhibited β1i subunit than BTZ (70% vs. 29% at 2.5 nM). In ALL/AML cell lines, IXA conveyed 50% growth inhibition at low nanomolar concentrations, but was ~10-fold less potent than BTZ. BTZ-resistant cells (150-160 fold) displayed similar (100-fold) cross-resistance to IXA. Finally, IXA and BTZ exhibited anti-leukemic effects for primary ex vivo ALL and AML cells; mean LC50 (nM) for IXA: 24 ± 11 and 30 ± 8, respectively, and mean LC50 for BTZ: 4.5 ± 1 and 11 ± 4, respectively. IXA has overlapping mechanisms of action with BTZ and showed anti-leukemic activity in primary leukemic cells, encouraging further pre-clinical in vivo evaluation.

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.

The proteasome as a target for protozoan parasites

Introduction: The proteasome is a multi-subunit enzyme complex responsible for the turnover of short-lived, abnormal or damaged proteins in eukaryotic cells. As organisms that undergo rapid growth and cell division, protozoan parasites exist on the knife-edge of proteotoxic catastrophe and thus rely heavily on their protein quality control machinery for survival. Because of this, the proteasome has recently emerged as a desirable drug target.Area covered: This review focuses on efforts to identify protozoan parasite-specific proteasome inhibitors using substrate profiling, library screening, and in vitro evolution of resistance approaches to inform medicinal chemistry. Targeting the parasite's 20S proteasome chymotrypsin-like (β5) activity and selectively inhibiting protein turnover in parasites compared to human cells are critical properties of potent, selective inhibitors.Expert opinion: Proteasome inhibitors have the potential for rapid action against all stages, all species and all strains of plasmodium and kinetoplastid parasites. Given the high level of conservation of proteasome active sites in eukaryotes, an important challenge is achieving inhibitors that show sufficient selectivity while maintaining properties consistent with drug development.