Current therapeutic strategies for multiple myeloma

Real-world study on adoption of standard of care (SoC) for transplant-eligible newly diagnosed multiple myeloma (TE-NDMM) patients between 2017 and 2020/2021 across France, Germany, Spain, and Italy

OBJECTIVES

This non-interventional observational study described the current standard-of-care (SoC) for transplant-eligible newly diagnosed multiple myeloma (TE-NDMM) patients in France, Germany, Spain, and Italy, and recorded the evolution in regimen adoption in distinct elements of frontline treatment during 2017-2020/2021.

METHODS

Clinical information on ongoing (I) or previous (II) TE-NDMM patients was extracted from the Cancerology database. Proportions of patients receiving regimens in each element and the evolution in regimen adoption were determined for the entire population and each country.

RESULTS

Most common induction regimens among I patients were VRd in France (75.3%) and Spain (44.1%), VTd in Italy (65.2%), and regimens other than VRd/VTd/VCd in Germany. Maintenance was ongoing/planned for 78.3%, 62.3%, 65.2%, and 61.4% patients in France, Germany, Spain, and Italy, respectively. Among II patients, VRd induction increased from 27.0% in 2017 to 65.7% in 2019 in France, remained relatively low in Spain and Germany, and not present in Italy. In Italy and Spain, VTd induction declined from 72.4% and 58.3% in 2017 to 52.8% and 17.3% in 2019, respectively. VCd induction in Germany declined from 85.2% in 2017 to 64.1% in 2019.

CONCLUSION

The use of bortezomib triplets in induction varied markedly over time and between selected countries.

Attenuation of STAT3 Signaling Cascade by Daidzin Can Enhance the Apoptotic Potential of Bortezomib against Multiple Myeloma

Daidzin (DDZ) extracted from Pueraria lobate (Fabaceae) is a widely known phytoestrogen. DDZ can display anti-cancer activities against breast and prostate cancers, but its anti-oncogenic actions in multiple myeloma (MM) cells have not been studied. The signal transducer and activator of transcription 3 (STAT3) can control key processes including proliferation, differentiation, and survival in MM cells. Here, we noted that DDZ abrogated STAT3 activation (both constitutive as well as inducible) at Tyr705 and Ser727 in MM cells. Additionally, DDZ mitigated the phosphorylation of STAT3 upstream Janus-activated kinases (JAK1/2) and c-Src kinases. Pervanadate (tyrosine phosphatase blocker) exposure altered the DDZ-induced inhibition of STAT3 activation, thus affecting the action of this phytoestrogen on apoptosis. Moreover, DDZ impeded proliferation and augmented the apoptotic effects of bortezomib (Bor) in MM cells. Overall, the data indicate that DDZ may act as a potent suppressor of STAT3 signaling cascade, and the co-treatment of DDZ and Bor could be a promising therapeutic strategy, specifically in MM.

Syrbactin proteasome inhibitor TIR-199 overcomes bortezomib chemoresistance and inhibits multiple myeloma tumor growth in vivo

Multiple myeloma (MM) and mantle cell lymphoma (MCL) are blood cancers that respond to proteasome inhibitors. Three FDA-approved drugs that block the proteasome are currently on the market, bortezomib, carfilzomib, and ixazomib. While these proteasome inhibitors have demonstrated clinical efficacy against refractory and relapsed MM and MCL, they are also associated with considerable adverse effects including peripheral neuropathy and cardiotoxicity, and tumor cells often acquire drug resistance. TIR-199 belongs to the syrbactin class, which constitutes a novel family of irreversible proteasome inhibitors. In this study, we compare TIR-199 head-to-head with three FDA-approved proteasome inhibitors. We demonstrate that TIR-199 selectively inhibits to varying degrees the sub-catalytic proteasomal activities (C-L/β1, T-L/β2, and CT-L/β5) in three actively dividing MM cell lines, with Ki₅₀ (CT-L/β5) values of 14.61 ± 2.68 nM (ARD), 54.59 ± 10.4 nM (U266), and 26.8 ± 5.2 nM (MM.1R). In most instances, this range was comparable with the activity of ixazomib. However, TIR-199 was more effective than bortezomib, carfilzomib, and ixazomib in killing bortezomib-resistant MM and MCL cell lines, as judged by a low resistance index (RI) between 1.7 and 2.2, which implies that TIR-199 indiscriminately inhibits both bortezomib-sensitive and bortezomib-resistant MM and MCL cells at similar concentrations. Importantly, TIR-199 reduced the tumor burden in a MM mouse model (p < 0.01) confirming its potency in vivo. Given the fact that there is still no cure for MM, the further development of TIR-199 or similar molecules that belong to the syrbactin class of proteasome inhibitors is warranted.

Immunoproteasome-selective inhibitors: An overview of recent developments as potential drugs for hematologic malignancies and autoimmune diseases

The immunoproteasome, a specialized form of proteasome, is mainly expressed in lymphocytes and monocytes of jawed vertebrates and responsible for the generation of antigenic peptides for cell-mediated immunity. Overexpression of immunoproteasome have been detected in a wide range of diseases including malignancies, autoimmune and inflammatory diseases. Following the successful approval of constitutive proteasome inhibitors bortezomib, carfilzomib and Ixazomib, and with the clarification of immunoproteasome crystal structure and functions, a variety of immunoproteasome inhibitors were discovered or rationally developed. Not only the inhibitory activities, the selectivities for immunoproteasome over constitutive proteasome are essential for the clinical potential of these analogues, which has been validated by the clinical evaluation of immunoproteasome-selective inhibitor KZR-616 for the treatment of systemic lupus erythematosus. In this review, structure, function as well as the current developments of various inhibitors against immunoproteasome are going to be summarized, which help to fully understand the target for drug discovery.

Pilot Study on the Cost of Some Oncohematology Diseases in Bulgaria

The goal of the current study is to perform a pilot study of the cost of some oncohematology diseases in Bulgaria. This is a pilot broader burden of disease research. The official report of the National health insurance fund provided information about the total expenditures paid for medicines, ambulatory services, and hospitalizations in 2015 and 2016. To evaluate the costs from a patient perspective, an internet inquiry was organized with the support of the patient organization. The inquiry contained questions regarding the patients' demography, type of oncohematology disease, year of diagnosis, quality of life (EuroQol v5D), and additional out of pocket expenditures. Quality of Life data were statistically analyzed and Kruskal-Wallis analysis of variance was performed. From 2015 to 2016 the number of patients with oncohematological diseases decreased by approximately 3000 people. Less than 30% were hospitalized and the hospitalization cost decreased, but the cost for medicines increased by nearly 1.5 million Euros. Cost for medicines almost tripled the hospitalization cost. The reported mean quality of life was 0.749 (SD 0.203). There was positive correlation between QoL and current disease state (p = 0.008) and age (p = 0.025). 42% reported to have additional expenditures related to their oncohematology disease, 22% reported other expenditures (diet, change of everyday habits etc.) and 42% reported to have productivity loses due to loss of employment or change of work, 44% of the respondents reported additional payment for medicines for concomitant diseases. Thus, the total cost (public funds and patients) accounted for 37,708,764 Euro. Despite the high public expenditures, the indirect costs due to productivity loses are higher. Costs for medicines are higher than costs of inpatient treatment, but this tendency is observed in all European countries. The increases in the costs of medicines are compensated by reduced costs of hospitalization. Despite their higher costs, newer medicines are an effective and reasonable investment from a societal perspective. Currently the higher levels of copayment increase the burden on the patients.

Chart review across EU5 in MM post-ASCT patients

Aim:

To understand the current treatment patterns, clinical outcomes and healthcare resource utilization–associated costs for multiple myeloma patients, post autologous stem cell transplant (ASCT) across Europe.

Patients & methods:

Medical records were used to abstract data for 337 multiple myeloma patients who had received ASCT.

Results:

Following ASCT, 7% received maintenance therapy prior to progression. Lenalidomide was the most frequently prescribed maintenance, second- and third-line therapy. Monthly resource use was considerably lower in patients who received maintenance therapy (€638.14 vs €1001.74). Median time to progression was longer for patients who had received maintenance therapy.

Conclusion:

The study highlights the diversity in current treatment patterns post-ASCT. Results suggest patients who receive maintenance therapy have a prolonged remission period, and as a result their associated healthcare resource utilization is spread across the treatment pathway.

Immunoproteasome inhibition and bioactivity of thiasyrbactins

A family of macrodilactam natural products, the syrbactins, are known proteasome inhibitors. A small group of syrbactin analogs was prepared with a sulfur-for-carbon substitution to enhance synthetic accessibility and facilitate modulation of their solubility. Two of these compounds surprisingly proved to be inhibitors of the trypsin-like catalytic site, including of the immunoproteasome. Their bound and free conformations suggest special properties of the thiasyrbactin ring are responsible for this unusual preference, which may be exploited to develop drug-like immunoproteasome inhibitors. These compounds show greater selectivity than earlier compounds used to infer phenotypes of immunoproteasome inhibition, like ONX-0914.

Panobinostat: A Review in Relapsed or Refractory Multiple Myeloma

Oral panobinostat (Farydak®), a potent nonselective histone deacetylase inhibitor, is approved in several countries for use in combination with bortezomib and dexamethasone in patients with multiple myeloma (MM) [USA] or relapsed and/or refractory MM (EU) who have received at least two prior treatment regimens, including bortezomib and an immunomodulatory drug (IMiD). In a pivotal phase III trial (PANORAMA 1) in patients with relapsed or relapsed and refractory MM who had received one to three previous lines of therapy, progression-free survival (PFS) was significantly prolonged with panobinostat plus bortezomib and dexamethasone compared with placebo plus bortezomib and dexamethasone. The significantly favourable effect of panobinostat- versus placebo-based treatment on PFS was also observed in a subgroup analysis of patients who had previously received an IMiD, bortezomib plus an IMiD, or at least two lines of treatment including bortezomib and an IMiD. Panobinostat plus bortezomib and dexamethasone had a generally manageable tolerability profile, with the most frequent grade 3-4 adverse events being myelosuppression, diarrhoea, asthenia or fatigue, peripheral neuropathy and pneumonia. Thus, panobinostat, in combination with bortezomib and dexamethasone, is a useful addition to the available treatment options for patients with relapsed or refractory MM.

Largazole Analogues Embodying Radical Changes in the Depsipeptide Ring: Development of a More Selective and Highly Potent Analogue

A number of analogues of the marine-derived histone deacetylase inhibitor largazole incorporating major structural changes in the depsipeptide ring were synthesized. Replacing the thiazole-thiazoline fragment of largazole with a bipyridine group gave analogue 7 with potent cell growth inhibitory activity and an activity profile similar to that of largazole, suggesting that conformational change accompanying switching hybridization from sp³ to sp² at C-7 is well tolerated. Analogue 7 was more class I selective compared to largazole, with at least 464-fold selectivity for class I HDAC proteins over class II HDAC6 compared to a 22-fold selectivity observed with largazole. To our knowledge 7 represents the first example of a potent and highly cytotoxic largazole analogue not containing a thiazoline ring. The elimination of a chiral center derived from the unnatural amino acid R-α-methylcysteine makes the molecule more amenable to chemical synthesis, and coupled with its increased class I selectivity, 7 could serve as a new lead compound for developing selective largazole analogues.

Synergistic anti-leukemic interactions between panobinostat and MK-1775 in acute myeloid leukemia ex vivo

MK-1775 is the first-in-class selective Wee1 inhibitor which has been demonstrated to synergize with CHK1 inhibitors in various malignancies. In this study, we report that the pan-histone deacetylase inhibitor (HDACI) panobinostat synergizes with MK-1775 in acute myeloid leukemia (AML), a malignancy which remains a clinical challenge and requires more effective therapies. Using both AML cell line models and primary patient samples, we demonstrated that panobinostat and MK-1775 synergistically induced proliferation arrest and cell death. We also demonstrated that panobinostat had equal anti-leukemic activities against primary AML blasts derived from patients either at initial diagnosis or at relapse. Interestingly, treatment with panobinostat alone or in combination with MK-1775 resulted in decreased Wee1 protein levels as well as downregulation of the CHK1 pathway. shRNA knockdown of CHK1 significantly sensitized AML cells to MK-1775 treatment, while knockdown of Wee1 significantly enhanced both MK-1775- and panobinostat-induced cell death. Our results demonstrate that panobinostat synergizes with MK-1775 in AML cells, at least in part through downregulation of CHK1 and/or Wee1, providing compelling evidence for the clinical development of the combination treatment in AML.

Multiple myeloma: patient outcomes in real-world practice

With increasing number of therapies available for the treatment of multiple myeloma, it is timely to examine the course of patients' journeys. We investigated patient characteristics, treatment durations and outcomes, and symptom burden across the treatment pathway in Belgium, France, Germany, Italy, Spain, Switzerland and the UK. In total, 435 physicians retrospectively reviewed 4997 patient charts. Profiles of patients diagnosed with multiple myeloma during the last 12 months were similar across countries; bone pain was the most common presentation. Median duration of first-line therapy was 6 months, followed by a median treatment-free interval of 10 months; both these decreased with increasing lines of therapy, as did time to progression. Depth of response, as assessed by the treating physician, also decreased with each additional line of therapy: 74% of patients achieved at least a very good partial response at first line, compared with only 11% at fifth line. Deeper responses were associated with longer time to progression, although these were physician-judged. Toxicities and co-morbidities increased with later treatment lines, and were more likely to have led to discontinuation of treatment. These real-world data provide an insight into patient outcomes and treatment decisions being made in clinical practice.

Novel phosphatidylinositol 3-kinase inhibitor BKM120 enhances the sensitivity of multiple myeloma to bortezomib and overcomes resistance

Proteasome inhibitor bortezomib has proven efficacy against multiple myeloma. However, bortezomib activates the phosphatidylinositol 3-kinase/AKT (PI3K/AKT) pathway (which is essential to the development of myeloma), often resulting in drug resistance and disease recurrence. The addition of BKM120 significantly enhanced the apoptotic effects of bortezomib in both bortezomib-sensitive and bortezomib-resistant cells. Treatment with bortezomib alone increased the phosphorylation of AKT (P-AKT), whereas the addition of BKM120 markedly downregulated P-AKT in both bortezomib-sensitive and bortezomib-resistant cells. The clinical relevance of combined treatment with bortezomib and BKM120 was investigated in a xenograft mouse model and in myeloma patients, and the synergy of the combination was confirmed. In conclusion, the addition of BKM120 enhanced the sensitivity of myeloma cells to bortezomib.

Computational Approaches for the Discovery of Human Proteasome Inhibitors: An Overview

Proteasome emerged as an important target in recent pharmacological research due to its pivotal role in degrading proteins in the cytoplasm and nucleus of eukaryotic cells, regulating a wide variety of cellular pathways, including cell growth and proliferation, apoptosis, DNA repair, transcription, immune response, and signaling processes. The last two decades witnessed intensive efforts to discover 20S proteasome inhibitors with significant chemical diversity and efficacy. To date, the US FDA approved to market three proteasome inhibitors: bortezomib, carfilzomib, and ixazomib. However new, safer and more efficient drugs are still required. Computer-aided drug discovery has long being used in drug discovery campaigns targeting the human proteasome. The aim of this review is to illustrate selected in silico methods like homology modeling, molecular docking, pharmacophore modeling, virtual screening, and combined methods that have been used in proteasome inhibitors discovery. Applications of these methods to proteasome inhibitors discovery will also be presented and discussed to raise improvements in this particular field.

Efficacy and Safety of Panobinostat in Relapsed or/and Refractory Multiple Myeloma: Meta Analyses of Clinical Trials and Systematic Review

During the past decades, many novel agents have improved response and survival of patients with multiple myeloma. Nevertheless, it remains challenging when they suffer relapsing. Thus, novel therapeutic agents are needed. We aimed to assess the efficacy and safety of a novel agent panobinostat for patients with relapsed or/and refractory MM. A systematic literature review identified studies for clinical trials about panobinostat in patients with relapsed or/and refractory MM. We searched studies published between January 2000 and December 2015 in Pubmed, Ovid, EBSCO and the Cochrane library. Random-effect pooled estimates were calculated for overall response rate and rates of common adverse effects. The results showed 11 clinical trials including 700 patients with relapsed or/and refractory MM treated with panobinostat were identified. The ORR varied between 0.08 and 0.67. Pooled analyses showed the results that the ORR was 0.45 (95% CI: 0.31–0.59, I² = 90.5%, P = 0.000) for panobinostat combined with any other kind of drugs. The most common Grade3/4 adverse effects were thrombocytopenia, neutropenia, lymphopenia, anemia, diarrhea, fatigue, nausea and so on. In conclusion, based on our analyses, the regimen of panobinostat combining with other agents seems to be well tolerated and efficacious in patients with relapsed or/and refractory MM.

Transcription factor IKZF1 is degraded during the apoptosis of multiple myeloma cells induced by kinase inhibition

Immunomodulatory drugs such as thalidomide, lenalidomide, and pomalidomide exhibit high responsive rates for newly identified or relapsed multiple myeloma patients. However, their mechanisms of action are not completely understood. One mechanism involves the ubiquitination and degradation of two transcription factors, IKZF1 and IKZF3. Whether there are other degradation pathways for IKZF1 in myeloma cells remains unknown. Here, we found that although IKZF1 ubiquitination was reduced, its stability was also significantly reduced in MM1.S and OPM2 cells treated with kinase inhibitors, 5,6-dichlorobenzimidazole riboside (DRB) or roscovitine. Through pharmacological inhibition and biochemical approaches we demonstrated that instead of undergoing the ubiquitin-proteasome pathway, IKZF1 was degraded through apoptosis induced by kinase inhibition. This result may provide a new direction in developing therapeutic treatments for myeloma patients.