A phase 1 dose-escalation study of filanesib plus bortezomib and dexamethasone in patients with recurrent/refractory multiple myeloma

The two sides of chromosomal instability: drivers and brakes in cancer

Chromosomal instability (CIN) is a hallmark of cancer and is associated with tumor cell malignancy. CIN triggers a chain reaction in cells leading to chromosomal abnormalities, including deviations from the normal chromosome number or structural changes in chromosomes. CIN arises from errors in DNA replication and chromosome segregation during cell division, leading to the formation of cells with abnormal number and/or structure of chromosomes. Errors in DNA replication result from abnormal replication licensing as well as replication stress, such as double-strand breaks and stalled replication forks; meanwhile, errors in chromosome segregation stem from defects in chromosome segregation machinery, including centrosome amplification, erroneous microtubule-kinetochore attachments, spindle assembly checkpoint, or defective sister chromatids cohesion. In normal cells, CIN is deleterious and is associated with DNA damage, proteotoxic stress, metabolic alteration, cell cycle arrest, and senescence. Paradoxically, despite these negative consequences, CIN is one of the hallmarks of cancer found in over 90% of solid tumors and in blood cancers. Furthermore, CIN could endow tumors with enhanced adaptation capabilities due to increased intratumor heterogeneity, thereby facilitating adaptive resistance to therapies; however, excessive CIN could induce tumor cells death, leading to the "just-right" model for CIN in tumors. Elucidating the complex nature of CIN is crucial for understanding the dynamics of tumorigenesis and for developing effective anti-tumor treatments. This review provides an overview of causes and consequences of CIN, as well as the paradox of CIN, a phenomenon that continues to perplex researchers. Finally, this review explores the potential of CIN-based anti-tumor therapy.

Mitotic Functions and Characters of KIF11 in Cancers

Mitosis mediates the accurate separation of daughter cells, and abnormalities are closely related to cancer progression. KIF11, a member of the kinesin family, plays a vital role in the formation and maintenance of the mitotic spindle. Recently, an increasing quantity of data have demonstrated the upregulated expression of KIF11 in various cancers, promoting the emergence and progression of cancers. This suggests the great potential of KIF11 as a prognostic biomarker and therapeutic target. However, the molecular mechanisms of KIF11 in cancers have not been systematically summarized. Therefore, we first discuss the functions of the protein encoded by KIF11 during mitosis and connect the abnormal expression of KIF11 with its clinical significance. Then, we elucidate the mechanism of KIF11 to promote various hallmarks of cancers. Finally, we provide an overview of KIF11 inhibitors and outline areas for future work.

A novel antibody-KSP inhibitor conjugate improves KSP inhibitor efficacy in vitro and in vivo

Many clinical trials of kinesin spindle protein (KSP) inhibitors have failed due to issues such as high toxicity and a short circulation half-life in vivo. To address the limitations of current KSP inhibitors and thus broad its use in antitumor therapy, this study applied antibody-drug conjugate (ADC) technology to the KSP inhibitor SB-743921, which was coupled with the HER2-specific antibody trastuzumab using a cathepsin B-dependent valine-alanine (Val-Ala, VA) dipeptide-type linker to generate H2-921. Ex vivo and in vivo analyses of H2-921 showed an increased half-life of SB-743921 and prolonged contact time with tumor cells. Furthermore, H2-921 induced apoptosis and incomplete autophagy in HER2-positive cells. In the in vivo analyses, H2-921 had significant tumor-targeting properties, and tumor inhibition by H2-921 was greater than that by traditional KSP inhibitors but similar to that by the positive control drug T-DM1. In conclusion, this study describes a novel application of ADC technology that enhances the antitumor effects of a KSP inhibitor and thus may effectively address the poor clinical efficacy of KSP inhibitors.

KIFC3 Regulates the progression and metastasis of gastric cancer via Notch1 pathway

INTRODUCTION

KIFC3 is a member of the kinesin family which has shown great promise in cancer therapy recently. In this study, we sought to elucidate the role of KIFC3 in the development of GC and its possible mechanisms.

METHODS

Two databases and a tissue microarray were used to explore the expression of KIFC3 and its correlation with patients' clinicopathological characteristics. Cell proliferation was examined by cell counting kit-8 assay and colony formation assay. Wound healing assay and transwell assay were performed to examine cell metastasis ability. EMT and Notch signaling related proteins were detected by western blot. Additionally, a xenograft tumor model was established to investigate the function of KIFC3 in vivo.

RESULTS

The expression of KIFC3 was upregulated in GC, and was associated with higher T stage and poor prognosis in GC patients. The proliferation and metastasis ability of GC cells were promoted by KIFC3 overexpression while inhibited by KIFC3 knockdown in vitro and in vivo. Furthermore, KIFC3 might activate the Notch1 pathway to facilitate the progression of GC, and DAPT, an inhibitor of Notch signaling, could reverse this effect.

CONCLUSION

Together, our data revealed that KIFC3 could enhance the progression and metastasis of GC by activating the Notch1 pathway.

Recent Advances in the Applications of Small Molecules in the Treatment of Multiple Myeloma

Therapy for multiple myeloma (MM), a hematologic neoplasm of plasma cells, has undergone remarkable changes over the past 25 years. Small molecules (molecular weight of less than one kDa), together with newer immunotherapies that include monoclonal antibodies, antibody-drug conjugates, and most recently, chimeric antigen receptor (CAR) T-cells, have combined to double the disease's five-year survival rate to over 50% during the past few decades. Despite these advances, the disease is still considered incurable, and its treatment continues to pose substantial challenges, since therapeutic refractoriness and patient relapse are exceedingly common. This review focuses on the current pipeline, along with the contemporary roles and future prospects for small molecules in MM therapy. While small molecules offer prospective benefits in terms of oral bioavailability, cellular penetration, simplicity of preparation, and improved cost-benefit considerations, they also pose problems of toxicity due to off-target effects. Highlighted in the discussion are recent developments in the applications of alkylating agents, immunomodulators, proteasome inhibitors, apoptosis inducers, kinesin spindle protein inhibitors, blockers of nuclear transport, and drugs that affect various kinases involved in intracellular signaling pathways. Molecular and cellular targets are described for each class of agents in relation to their roles as drivers of MM.

Role of KSP inhibitors as anti-cancer therapeutics: an update

Regardless of the growing discovery of anticancer treatments, targeting cancer-specific pathways, cytotoxic therapy still maintained its abundant clinical significance based on the fact that tumours harbour a greater population of actively dividing cells than normal tissues. Conventional anti-mitotic agents or microtubule poisons acting on the major mitotic spindle protein tubulin have been effectively used in clinical settings for cancer chemotherapy over the last three decades. However, use of these drugs is associated with limited clinical utility due to serious side effects such as debilitating and dose-limiting peripheral neuropathy, myelosuppression, drug resistance and allergic reactions. Therefore, research initiatives have been undertaken to develop novel microtubule motor proteins inhibitors that can potentially circumvent the limitations associated with conventional microtubule poisons. Kinesin spindle proteins (KSP) belonging to the kinesin-5 family play a crucial role during mitosis and unregulated cell proliferation. Several evidences from preclinical studies and different phases of clinical trials have presented kinesin spindle protein as a promising target for cancer therapeutics. kinesin spindle protein inhibitors causing mitosis disruption without interfering with microtubule dynamics in non-dividing cells offer a potential therapeutic alternative for the management of several major cancer types and are devoid of side effects associated with classical anti-mitotic drugs. This review summarizes recent data highlighting progress in the discovery of targeted KSP inhibitors and presents the development of scaffolds, structure-activity relationships, and outcomes of biological, and enzyme inhibition studies. We reviewed the recent literature reports published over last decade, using various electronic database searches such as PubMed, Embase, Medline, Web of Science, and Google Scholar. Clinical trial data till 2021 was retrieved from ClinicalTrial.gov. Major chemical classes developed as selective KSP inhibitors include dihydropyrimidines, β-carbolines, carbazoles, benzimidazoles, fused aryl derivatives, pyrimidines, fused pyrimidines, quinazolines, quinolones, thiadiazolines, spiropyran and azobenzenes. Drugs such as filanesib, litronesib, ispinesib have entered clinical trials, the most advanced phase explored being Phase II. KSP inhibitors have exhibited promising results; however, continued exploration is greatly required to establish the clinical potential of KSP inhibitors.

Filanesib plus bortezomib and dexamethasone in relapsed/refractory t(11;14) and 1q21 gain multiple myeloma

Filanesib is a first-in-class kinesin spindle protein inhibitor which demonstrated safety and encouraging activity in combination with bortezomib and dexamethasone in relapsed/refractory multiple myeloma in a preliminary analysis of dose-escalation phase results. This multicenter study included first a dose-escalation phase to determine maximum tolerated dose of two schedules of filanesib, bortezomib, and dexamethasone and a subsequent dose-expansion phase using the maximum tolerated doses. In the dose-expansion phase, 28 patients were evaluable for safety and efficacy. The most common grade ≥3 adverse events were neutropenia (21%) and anemia (18%), which were noncumulative and reversible, and hypertension (18%). The overall response rate was 43% with median duration of response not yet reached (range, 2.8-23.7+ months) with median follow-up of 6.3 months. A post hoc analysis incorporated 29 dose-escalation phase patients who received therapeutic filanesib doses, with an overall response rate of 39% and median duration of response of 18.0 months among the 57 total patients with median progression-free survival of 8.5 months. Notably, the PFS of high risk patients was comparable at 8.5 months, driven by the patients with 1q21 gain, characterized by increased MCL-1 expression, with a PFS of 9.1 months versus 3.5 months for the remainder of high risk patients. Patients with t(11;14) also had an encouraging PFS of 15.0 months. The combination of filanesib, bortezomib, and dexamethasone continues to show safety and encouraging activity in relapsed/refractory multiple myeloma, particularly in those patients with 1q21 gain and t(11;14).

Second-Generation Antimitotics in Cancer Clinical Trials

Mitosis represents a promising target to block cancer cell proliferation. Classical antimitotics, mainly microtubule-targeting agents (MTAs), such as taxanes and vinca alkaloids, are amongst the most successful anticancer drugs. By disrupting microtubules, they activate the spindle assembly checkpoint (SAC), which induces a prolonged delay in mitosis, expected to induce cell death. However, resistance, toxicity, and slippage limit the MTA's effectiveness. With the desire to overcome some of the MTA's limitations, mitotic and SAC components have attracted great interest as promising microtubule-independent targets, leading to the so-called second-generation antimitotics (SGAs). The identification of inhibitors against most of these targets, and the promising outcomes achieved in preclinical assays, has sparked the interest of academia and industry. Many of these inhibitors have entered clinical trials; however, they exhibited limited efficacy as monotherapy, and failed to go beyond phase II trials. Combination therapies are emerging as promising strategies to give a second chance to these SGAs. Here, an updated view of the SGAs that reached clinical trials is here provided, together with future research directions, focusing on inhibitors that target the SAC components.

The Landscape of Signaling Pathways and Proteasome Inhibitors Combinations in Multiple Myeloma

Multiple myeloma is a malignancy of terminally differentiated plasma cells, characterized by an extreme genetic heterogeneity that poses great challenges for its successful treatment. Due to antibody overproduction, MM cells depend on the precise regulation of the protein degradation systems. Despite the success of PIs in MM treatment, resistance and adverse toxic effects such as peripheral neuropathy and cardiotoxicity could arise. To this end, the use of rational combinatorial treatments might allow lowering the dose of inhibitors and therefore, minimize their side-effects. Even though the suppression of different cellular pathways in combination with proteasome inhibitors have shown remarkable anti-myeloma activities in preclinical models, many of these promising combinations often failed in clinical trials. Substantial progress has been made by the simultaneous targeting of proteasome and different aspects of MM-associated immune dysfunctions. Moreover, targeting deranged metabolic hubs could represent a new avenue to identify effective therapeutic combinations with PIs. Finally, epigenetic drugs targeting either DNA methylation, histone modifiers/readers, or chromatin remodelers are showing pleiotropic anti-myeloma effects alone and in combination with PIs. We envisage that the positive outcome of patients will probably depend on the availability of more effective drug combinations and treatment of early MM stages. Therefore, the identification of sensitive targets and aberrant signaling pathways is instrumental for the development of new personalized therapies for MM patients.

KIF11 inhibitors filanesib and ispinesib inhibit meningioma growth in vitro and in vivo

Treatment of aggressive meningiomas remains challenging due to a high rate of recurrence in higher-grade meningiomas, frequent subtotal resections, and the lack of effective systemic treatments. Substantial overexpression associated with a poor prognosis has been demonstrated for kinesin family member 11 (KIF11) in high-grade meningiomas. Due to anti-tumor activity for KIF11 inhibitors (KIF11i) filanesib and ispinesib in other cancer types, we sought to investigate their mode of action and efficacy for the treatment of aggressive meningiomas. Dose curve analysis of both KIF11i revealed IC50 values of less than 1 nM in anaplastic and benign meningioma cell lines. Both compounds induced G2/M arrest and subsequent subG1 increase in all cell lines. Profound induction of apoptosis was detected in the anaplastic cell lines determined by annexin V staining. KIF11i significantly inhibited meningioma growth in xenotransplanted mice by up to 83%. Furthermore, both drugs induced minor hematological side effects, which were less pronounced for filanesib. We identified substantial in vitro and in vivo anti-tumor effects of the KIF11 inhibitors filanesib and ispinesib, with filanesib demonstrating better tolerability, suggesting future use of filanesib for the treatment of aggressive meningioma.

Eg5 targeting agents: From new anti-mitotic based inhibitor discovery to cancer therapy and resistance

Eg5, the product of Kif11 gene, also known as kinesin spindle protein, is a motor protein involved in the proper establishment of a bipolar mitotic spindle. Eg5 is one of the 45 different kinesins coded in the human genome of the kinesin motor protein superfamily. Over the last three decades Eg5 has attracted great interest as a promising new mitotic target. The identification of monastrol as specific inhibitor of the ATPase activity of the motor domain of Eg5 inhibiting the Eg5 microtubule motility in vitro and in cellulo sparked an intense interest in academia and industry to pursue the identification of novel small molecules that target Eg5 in order to be used in cancer chemotherapy based on the anti-mitotic strategy. Several Eg5 inhibitors entered clinical trials. Currently the field is faced with the problem that most of the inhibitors tested exhibited only limited efficacy. However, one Eg5 inhibitor, Arry-520 (clinical name filanesib), has demonstrated clinical efficacy in patients with multiple myeloma and is scheduled to enter phase III clinical trials. At the same time, new trends in Eg5 inhibitor research are emerging, including an increased interest in novel inhibitor binding sites and a focus on drug synergy with established antitumor agents to improve chemotherapeutic efficacy. This review presents an updated view of the structure and function of Eg5-inhibitor complexes, traces the possible development of resistance to Eg5 inhibitors and their potential therapeutic applications, and surveys the current challenges and future directions of this active field in drug discovery.

New drugs in early development for treating multiple myeloma: all that glitters is not gold

INTRODUCTION

The last twenty years have introduced new therapeutic agents for multiple myeloma (MM); these include proteasome inhibitors (PIs), immunomodulatory drugs (IMDs) and monoclonal antibodies (mAbs). However, MM remains incurable, hence there is an unmet need for new agents for the treatment of advanced refractory disease. New agents could also be used in early lines to achieve improved, more sustained remission.

AREAS COVERED

We review the most promising agents investigated in early-phase trials for the treatment of MM and provide an emphasis on new agents directed against well-known targets (new PIs, IMDs and anti-CD38 mAbs). Drugs that work through distinct and numerous mechanisms of action (e.g. pro-apoptotic agents and tyrosine kinase inhibitors) and innovative immunotherapeutic approaches are also described. The paper culminates with our perspective on therapeutic approaches on the horizon for this disease.

EXPERT OPINION

IMD iberdomide and the export protein inhibitor selinexor demonstrated efficacy in heavily pretreated patients who had no other therapeutic options. We expect that immunotherapy with anti-BCMA BTEs and ADCs will revolutionize the approach to treating the early stages of the disease. Data on venetoclax in t(11;14)-positive patients may pave the way for personalized therapy. Not all new agents under early clinical evaluation will be investigated in regulatory phase III trials; one of the most important challenges is to identify those that could make a difference.

Thiadiazole derivatives as anticancer agents

In spite of substantial progress made toward understanding cancer pathogenesis, this disease remains one of the leading causes of mortality. Thus, there is an urgent need to develop novel, more effective anticancer therapeutics. Thiadiazole ring is a versatile scaffold widely studied in medicinal chemistry. Mesoionic character of this ring allows thiadiazole-containing compounds to cross cellular membrane and interact strongly with biological targets. Consequently, these compounds exert a broad spectrum of biological activities. This review presents the current state of knowledge on thiadiazole derivatives that demonstrate in vitro and/or in vivo efficacy across the cancer models with an emphasis on targets of action. The influence of the substituent on the compounds' activity is depicted. Furthermore, the results from clinical trials assessing thiadiazole-containing drugs in cancer patients are summarized.

Filanesib in combination with pomalidomide and dexamethasone in refractory MM patients: safety and efficacy, and association with alpha 1-acid glycoprotein (AAG) levels. Phase Ib/II Pomdefil clinical trial conducted by the Spanish MM group

This phase I/II trial evaluated the combination of the kinesin spindle protein inhibitor filanesib with pomalidomide and dexamethasone in relapsed or refractory multiple myeloma (RRMM) patients. Forty-seven RRMM patients with a median of three prior lines (2-8) and 94% refractory to lenalidomide were included: 14 in phase I and 33 in phase II. The recommended dose was 1·25 mg/m² of filanesib on days 1, 2, 15, 16, with pomalidomide 4 mg on days 1-21 and dexamethasone 40 mg weekly. The defined threshold for success was achieved, with 18 out of 31 patients obtaining at least minor response (MR) in the phase II. In the global population, 51% of patients achieved at least partial response (PR) and 60% ≥MR, resulting in a median progression-free survival (mPFS) of seven months and overall survival (OS) of 19 months. The main toxicity was haematological. Importantly, patients with low serum levels of alpha 1-acid glycoprotein (AAG) at baseline (<800 mg/l) had a superior response (overall response rate of 62% vs. 17%; P = 0·04), which also translated into a longer mPFS (9 vs. 2 months; P = 0·014). In summary, filanesib with pomalidomide and dexamethasone is active in RRMM although with significant haematological toxicity. Most importantly, high levels of AAG can identify patients unlikely to respond to this strategy. Trial registration: clinicaltrials.gov identifier: NCT02384083.

Drug Targeting of Genomic Instability in Multiple Myeloma

Genomic instability can be observed at both chromosomal and chromatin levels. Instability at the macro level includes centrosome abnormalities (CA) resulting in numerical as well as structural chromosomal changes, whereas instability at the micro level is characterized by defects in DNA repair pathways resulting in microsatellite instability (MIN) or mutations. Genomic instability occurs during carcinogenesis without impairing survival and growth, though the precise mechanisms remain unclear. Solid tumors arising from most cells of epithelial origin are characterized by genomic instability which renders them resistant to chemotherapy and radiotherapy. This instability is also observed in 25% of myeloma patients and has been shown to be highly prognostic, independently of the international staging system (ISS). However, a biomarker of aberrant DNA repair and loss of heterozygosity (LOH), was only observed at a frequency of 5% in newly diagnosed patients. Several new molecules targeting the pathways involved in genomic instability are under development and some have already entered clinical trials. Poly(ADP-ribose) polymerase-1 (PARP) inhibitors have been FDA-approved for the treatment of breast cancer type 1 susceptibility protein (BRCA1)-mutated metastatic breast cancer, as well as ovarian and lung cancer. Topoisomerase inhibitors and epigenetic histone modification-targeting inhibitors, such as HDAC (Histone Deacetylase) inhibitors which are novel agents that can target genomic instability. Several of the small molecule inhibitors targeting chromosomal level instability such as PARP, Akt, Aurora kinase, cyclin dependent kinase or spindle kinase inhibitors have been tested in mouse models and early phase I/II trials. ATM, ATR kinase inhibitors and DNA helicase inhibitors are also promising novel agents. However, most of these drugs are not effective as single agents but appear to act synergistically with DNA damaging agents such as radiotherapy, platinum derivatives, immunomodulators, and proteasome inhibitors. In this review, new drugs targeting genomic instability and their mechanisms of action will be discussed.

Trial watch: chemotherapy-induced immunogenic cell death in immuno-oncology

The term ‘immunogenic cell death’ (ICD) denotes an immunologically unique type of regulated cell death that enables, rather than suppresses, T cell-driven immune responses that are specific for antigens derived from the dying cells. The ability of ICD to elicit adaptive immunity heavily relies on the immunogenicity of dying cells, implying that such cells must encode and present antigens not covered by central tolerance (antigenicity), and deliver immunostimulatory molecules such as damage-associated molecular patterns and cytokines (adjuvanticity). Moreover, the host immune system must be equipped to detect the antigenicity and adjuvanticity of dying cells. As cancer (but not normal) cells express several antigens not covered by central tolerance, they can be driven into ICD by some therapeutic agents, including (but not limited to) chemotherapeutics of the anthracycline family, oxaliplatin and bortezomib, as well as radiation therapy. In this Trial Watch, we describe current trends in the preclinical and clinical development of ICD-eliciting chemotherapy as partner for immunotherapy, with a focus on trials assessing efficacy in the context of immunomonitoring.

Identification of KIF11 As a Novel Target in Meningioma

Kinesins play an important role in many physiological functions including intracellular vesicle transport and mitosis. The emerging role of kinesins in different cancers led us to investigate the expression and functional role of kinesins in meningioma. Therefore, we re-analyzed our previous microarray dataset of benign, atypical, and anaplastic meningiomas (n = 62) and got evidence for differential expression of five kinesins (KIFC1, KIF4A, KIF11, KIF14 and KIF20A). Further validation in an extended study sample (n = 208) revealed a significant upregulation of these genes in WHO°I to °III meningiomas (WHO°I n = 61, WHO°II n = 88, and WHO°III n = 59), which was most pronounced in clinically more aggressive tumors of the same WHO grade. Immunohistochemical staining confirmed a WHO grade-associated upregulated protein expression in meningioma tissues. Furthermore, high mRNA expression levels of KIFC1, KIF11, KIF14 and KIF20A were associated with shorter progression-free survival. On a functional level, knockdown of kinesins in Ben-Men-1 cells and in the newly established anaplastic meningioma cell line NCH93 resulted in a significantly inhibited tumor cell proliferation upon siRNA-mediated downregulation of KIF11 in both cell lines by up to 95% and 71%, respectively. Taken together, in this study we were able to identify the prognostic and functional role of several kinesin family members of which KIF11 exhibits the most promising properties as a novel prognostic marker and therapeutic target, which may offer new treatment options for aggressive meningiomas.

Immunogenic cell death in anticancer chemotherapy and its impact on clinical studies

The traditional view holds that apoptosis is non-immunogenic and does not induce an inflammatory response. However, recent studies have suggested that certain chemotherapeutic drugs that induce tumor cell apoptosis can induce immunogenic cell death (ICD) in cancer cells. This process is characterized by not only up-regulation of a series of signaling molecules in cancer cells, including expose of calreticulin (CRT), secretion of adenosine triphosphate (ATP) and release of high mobility group box 1 (HMGB1). In this review, we summarize recent progress in identifying and classifying ICD inducers; concepts and molecular mechanisms of ICD; and the impact and potential applications of ICD in clinical studies. We also discuss the contributions of ICD inducers in combination with other anticancer drugs in clinical applications.

The Multiple Myeloma Drug Pipeline-2018: A Review of Small Molecules and Their Therapeutic Targets

Treatment of multiple myeloma (MM), a neoplasm of plasma cells, formerly dependent on alkylating drugs, corticosteroids, and autologous stem cell transplantation, has changed dramatically in the past 20 years because 3 new classes of small molecule drugs (arbitrarily defined as having a molecular weight of < 900 kDa)-immunomodulators, proteasome inhibitors, and histone deacetylase blockers-have been introduced for the disease. Therapeutic options for MM expanded further in 2015 when 2 new monoclonal antibodies (daratumumab and elotuzumab) were approved by the Food and Drug Administration for MM. Although MM remains incurable, the cumulative effect of these advances has resulted in a near-doubling of the 5-year survival rate since the late 1980s. Despite these advances, therapy for MM continues to pose substantial challenges because resistance to therapy frequently develops, and relapse and recurrence are all too common. The present review focused on the pipeline for new small molecules in various stages of development and their associated cellular targets. In addition to newer versions of alkylators, immunomodulators, proteasome inhibitors, and histone deacetylase inhibitors, the present review considered the prospects for adding new classes of small molecules to the MM armamentarium, which offer the potential for oral efficacy, relative simplicity of preparation, and prospects for improvement in the cost-to-benefit ratio. Included are agents that affect myeloma epigenetics and the ubiquitination-proteasome system and the unfolded protein response, apoptotic mechanisms, chromosomal abnormalities, nuclear protein transport, and various kinases involved in cellular signaling pathways.

Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics

The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.

A Phase 1 and 2 study of Filanesib alone and in combination with low-dose dexamethasone in relapsed/refractory multiple myeloma

BACKGROUND

Filanesib (ARRY-520) is a highly selective inhibitor of kinesin spindle protein, which has demonstrated preclinical antimyeloma activity.

METHODS

This open-label Phase 1/2 study determined the maximum tolerated dose of Filanesib administered on Days 1 and 2 of 14-Day Cycles in patients with multiple myeloma (MM) and included expansion cohorts with and without dexamethasone (40 mg/week). Patients in the dose-escalation (N = 31) and Phase 2 single-agent (N = 32) cohorts had received prior bortezomib as well as prior thalidomide and/or lenalidomide. Patients in the Phase 2 Filanesib plus dexamethasone cohort (N = 55) had received prior alkylator therapy and had disease refractory to lenalidomide, bortezomib, and dexamethasone. Prophylactic filgrastim was incorporated during dose escalation and was used throughout Phase 2.

RESULTS

Patients in each cohort had received a median of ≥6 prior therapies. The most common dose-limiting toxicities were febrile neutropenia and mucosal inflammation. In Phase 2, Grade 3 and 4 cytopenias were reported in approximately 50% of patients. Nonhematologic toxicities were infrequent. Phase 2 response rates (partial responses or better) were 16% (single agent) and 15% (Filanesib plus dexamethasone). All responding patients had low baseline levels of α1-acid glycoprotein, a potential selective biomarker.

CONCLUSIONS

Filanesib 1.50 mg/m² /day administered with prophylactic filgrastim has a manageable safety profile and encouraging activity in heavily pretreated patients This study is registered at www.clinicaltrials.gov as NCT00821249. Cancer 2017;123:4617-4630. © 2017 American Cancer Society.

The therapeutic potential of cell cycle targeting in multiple myeloma

Proper cell cycle progression through the interphase and mitosis is regulated by coordinated activation of important cell cycle proteins (including cyclin-dependent kinases and mitotic kinases) and several checkpoint pathways. Aberrant activity of these cell cycle proteins and checkpoint pathways results in deregulation of cell cycle progression, which is one of the key hallmarks of cancer. Consequently, intensive research on targeting these cell cycle regulatory proteins identified several candidate small molecule inhibitors that are able to induce cell cycle arrest and even apoptosis in cancer cells. Importantly, several of these cell cycle regulatory proteins have also been proposed as therapeutic targets in the plasma cell malignancy multiple myeloma (MM). Despite the enormous progress in the treatment of MM the past 5 years, MM still remains most often incurable due to the development of drug resistance. Deregulated expression of the cyclins D is observed in virtually all myeloma patients, emphasizing the potential therapeutic interest of cyclin-dependent kinase inhibitors in MM. Furthermore, other targets have also been identified in MM, such as microtubules, kinesin motor proteins, aurora kinases, polo-like kinases and the anaphase promoting complex/cyclosome. This review will provide an overview of the cell cycle proteins and checkpoint pathways deregulated in MM and discuss the therapeutic potential of targeting proteins or protein complexes involved in cell cycle control in MM.

Safety issues and management of toxicities associated with new treatments for multiple myeloma

INTRODUCTION

In the last decade, the availability of new drugs for the treatment of Multiple Myeloma (MM) significantly improved patients' outcomes, but also raised attention towards a new spectrum of adverse events. Recently, four novel agents with different mechanisms of action (carfilzomib, elotuzumab, daratumumab and panobinostat) have been approved for the treatment of MM. This review aims at providing physicians with the tools to recognize and handle toxicity issues related with these new treatments. Areas covered: This review focuses on the management of drug related adverse events of the latest approved drug combinations. New drug combinations under development and still in the phase of approval will be briefly discussed. PubMed was searched using the terms 'toxicity', 'carfilzomib', 'elotuzumab' 'daratumumab' and 'panobinostat'. Phase II and III clinical trials and previously published analyses on toxicities were reviewed. For new drug combination abstracts presented at the latest ASH, ASCO and EHA meetings as well as clinicaltrial.gov website was searched and reviewed. Expert commentary: With the development of newer drugs and the availability of different treatment options for MM patients, an accurate evaluation of treatment side effects, their prompt recognition and management is mandatory for all clinical hematologists.