Vinflunine in the treatment of advanced urothelial cancer: clinical evidence and experience

A Transformable Specific-Responsive Peptide for One-Step Synergistic Therapy of Bladder Cancer

Synergistic therapy has shown greater advantages compared with monotherapy. However, the complex multiple-administration plan and potential side effects limit its clinical application. A transformable specific-responsive peptide (TSRP) is utilized to one-step achieve synergistic therapy integrating anti-tumor, anti-angiogenesis and immune response. The TSRP is composed of: i) Recognition unit could specifically target and inhibit the biological function of FGFR-1; ii) Transformable unit could self-assembly and trigger nanofibers formation; iii) Reactive unit could specifically cleaved by MMP-2/9 in tumor micro-environment; iv) Immune unit, stimulate the release of immune cells when LTX-315 (Immune-associated oncolytic peptide) exposed. Once its binding to FGFR-1, the TSRP could cleaved by MMP-2/9 to form the nanofibers on the cell membrane, with a retention time of up to 12 h. Through suppressing the phosphorylation levels of ERK 1/2 and PI3K/AKT signaling pathways downstream of FGFR-1, the TSRP significant inhibit the growth of tumor cells and the formation of angioginesis. Furthermore, LTX-315 is exposed after TSRP cleavage, resulting in Calreticulin activation and CD8+ T cells infiltration. All above processes together contribute to the increasing survival rate of tumor-bearing mice by nearly 4-folds. This work presented a unique design for the biological application of one-step synergistic therapy of bladder cancer.

An update on the development on tubulin inhibitors for the treatment of solid tumors

INTRODUCTION

Microtubules play a vital role in cancer therapeutics. They are implicated in tumorigenesis, thus inhibiting tubulin polymerization in cancer cells, and have now become a significant target for anticancer drug development. A plethora of drug molecules has been crafted to influence microtubule dynamics and presently, numerous tubulin inhibitors are being investigated. This review discusses the recently developed inhibitors including natural products, and also examines the preclinical and clinical data of some potential molecules.

AREA COVERED

The current review article summarizes the development of tubulin inhibitors while detailing their specific binding sites. It also discusses the newly designed inhibitors that may be useful in the treatment of solid tumors.

EXPERT OPINION

Microtubules play a crucial role in cellular processes, especially in cancer therapy where inhibiting tubulin polymerization holds promise. Ongoing trials signify a commitment to revolutionizing cancer treatment and exploring targeted therapies. Challenges in microtubule modulation, like resistance and off-target effects, demand focused efforts, emphasizing combination therapies and personalized treatments. Beyond microtubules, promising avenues in cancer research include immunotherapy, genomic medicine, CRISPR gene editing, liquid biopsies, AI diagnostics, and stem cell therapy, showcasing a holistic approach for future advancements.

Recent Advancements in the Synthesis of α-fluoroalkylated Azine-derived Heterocycles through Direct Fluorination

The review highlights recent advancements in the synthesis of α-fluoro and α,α- difluoroalkylated azines, focusing on two main approaches. The first approach involves nucleophilic deoxofluorination, wherein α-hydroxy- or α-oxoalkylated azines are treated with diethylaminosulfur trifluoride or other S-F reagents to introduce fluorine atoms. The second approach employs direct electrophilic benzylic fluorination, whereby alkylazines undergo fluorination using N-F reagents. Both methods provide flexibility in designing and synthesizing fluoroalkylated heterocycles.

Therapeutic Role of Alkaloids and Alkaloid Derivatives in Cancer Management

Cancer is a neoplastic disease that remains a global challenge with a reported prevalence that is increasing annually. Though existing drugs can be applied as single or combined therapies for managing this pathology, their concomitant adverse effects in human applications have led to the need to continually screen natural products for effective and alternative anticancer bioactive principles. Alkaloids are chemical molecules that, due to their structural diversity, constitute a reserve for the discovery of lead compounds with interesting pharmacological activities. Several in vitro studies and a few in vivo findings have documented various cytotoxic and antiproliferative properties of alkaloids. This review describes chaetocochin J, neopapillarine, coclaurine, reflexin A, 3,10-dibromofascaplysin and neferine, which belong to different alkaloid classes with antineoplastic properties and have been identified recently from plants. Despite their low solubility and bioavailability, plant-derived alkaloids have viable prospects as sources of viable lead antitumor agents. This potential can be achieved if more research on these chemical compounds is directed toward investigating ways of improving their delivery in an active form close to target cells, preferably with no effect on neighboring normal tissues.

Evaluating real-world characteristics of patients with advanced urothelial carcinoma eligible for avelumab maintenance therapy: a multi-country retrospective medical chart review

INTRODUCTION

Urothelial carcinoma (UC) is a malignancy of the urothelium that encompasses the renal pelvis, bladder, and urethra. Current treatment guidelines for advanced (ie, locally advanced or metastatic) UC recommend using avelumab maintenance therapy in patients with nonprogressive disease following first-line platinum-based chemotherapy. This study aimed to assess the representativeness of the patient population in the JAVELIN Bladder 100 (JB-100) trial, which examined the efficacy and safety of avelumab first-line maintenance, vs. real-world patients with advanced UC that had not progressed with first-line platinum-based chemotherapy treated between 2015 and 2018 by reviewing demographic and clinical characteristics.

PATIENTS AND METHODS

A medical chart review (MCR) study collected demographics and treatment characteristics for patients with advanced UC in the United States, the United Kingdom, and France. Data were analyzed descriptively for review with data collected from patients enrolled in JB-100.

RESULTS

Clinical characteristics were consistent between JB-100 and the MCR. Most patients were male, received 4 to 6 cycles of platinum-based chemotherapy, and had an Eastern Cooperative Oncology Group performance status of 0 or 1. All patients in the MCR had either stable disease or a response with platinum-based chemotherapy (∼75% achieved a complete or partial response). Fewer than half (42.5%) of all patients in the MCR received subsequent therapy.

CONCLUSION

Patient demographics, clinical characteristics, and treatment patterns from a MCR of patients with advanced UC that had not progressed following first-line platinum-based chemotherapy appeared similar to data from patients enrolled in JB-100. Future studies should examine whether real-world outcomes are consistent with findings from JB-100.

CLINICALTRIALS

GOV IDENTIFIER

NCT02603432.

Daniellia oliveri (Rolfe) Hutch and Dalziel: Antimicrobial Activities, Cytotoxicity Evaluation, and Phytochemical Identification by GC-MS

During a previous study that identified plants used in traditional medicine in Togo to treat infectious diseases, Daniellia oliveri was specifically reported to treat intertrigo and candidiasis. Consequently, to explore the anti-infective potential of this plant, we investigated the antibacterial and the antifungal activity of the plant's parts, as well as the cytotoxic activities of raw extracts and subsequent fractions, and the chemical composition of the most active fractions. In order to evaluate the antimicrobial activity, MICs were determined using the broth dilution method. Then, the most active fractions were evaluated for cytotoxicity by using normal human cells (MRC-5 cells) via the MTT assay. Finally, the most active and not toxic fractions were phytochemically investigated by GC-MS. Interestingly, all the raw extracts and fractions were active against the bacteria tested, with MICs ranging from 16 µg/mL to 256 µg/mL, while no antifungal activity was observed at 256 µg/mL, the highest tested concentration. Moreover, no toxicity was observed with most of the active fractions. The subsequent chemical investigation of the most interesting fractions led to identifying terpenes, phytosterols, phenolic compounds, and fatty acids as the main compounds. In conclusion, this study demonstrated that D. oliveri possesses valuable antibacterial activities in accordance with traditional use.

Addressing artifacts of colorimetric anticancer assays for plant-based drug development

Cancer has become the silent killer in less-developed countries and the most significant cause of morbidity worldwide. The accessible and frequently used treatments include surgery, radiotherapy, chemotherapy, and immunotherapy. Chemotherapeutic drugs traditionally involve using plant-based medications either in the form of isolated compounds or as scaffolds for synthetic drugs. To launch a drug in the market, it has to pass through several intricate steps. The multidrug resistance in cancers calls for novel drug discovery and development. Every year anticancer potential of several plant-based compounds and extracts is reported but only a few advances to clinical trials. The false-positive or negative results impact the progress of the cell-based anticancer assays. There are several cell-based assays but the widely used include MTT, MTS, and XTT. In this article, we have discussed various pitfalls and workable solutions.

Shooting at Moving and Hidden Targets-Tumour Cell Plasticity and the Notch Signalling Pathway in Head and Neck Squamous Cell Carcinomas

Head and Neck Squamous Cell Carcinoma (HNSCC) is often aggressive, with poor response to current therapies in approximately 40-50% of the patients. Current therapies are restricted to operation and irradiation, often combined with a small number of standard-of-care chemotherapeutic drugs, preferentially for advanced tumour patients. Only very recently, newer targeted therapies have entered the clinics, including Cetuximab, which targets the EGF receptor (EGFR), and several immune checkpoint inhibitors targeting the immune receptor PD-1 and its ligand PD-L1. HNSCC tumour tissues are characterized by a high degree of intra-tumour heterogeneity (ITH), and non-genetic alterations that may affect both non-transformed cells, such as cancer-associated fibroblasts (CAFs), and transformed carcinoma cells. This very high degree of heterogeneity likely contributes to acquired drug resistance, tumour dormancy, relapse, and distant or lymph node metastasis. ITH, in turn, is likely promoted by pronounced tumour cell plasticity, which manifests in highly dynamic and reversible phenomena such as of partial or hybrid forms of epithelial-to-mesenchymal transition (EMT), and enhanced tumour stemness. Stemness and tumour cell plasticity are strongly promoted by Notch signalling, which remains poorly understood especially in HNSCC. Here, we aim to elucidate how Notch signal may act both as a tumour suppressor and proto-oncogenic, probably during different stages of tumour cell initiation and progression. Notch signalling also interacts with numerous other signalling pathways, that may also have a decisive impact on tumour cell plasticity, acquired radio/chemoresistance, and metastatic progression of HNSCC. We outline the current stage of research related to Notch signalling, and how this pathway may be intricately interconnected with other, druggable targets and signalling mechanisms in HNSCC.

Diversity in Chemical Structures and Biological Properties of Plant Alkaloids

Phytochemicals belonging to the group of alkaloids are signature specialized metabolites endowed with countless biological activities. Plants are armored with these naturally produced nitrogenous compounds to combat numerous challenging environmental stress conditions. Traditional and modern healthcare systems have harnessed the potential of these organic compounds for the treatment of many ailments. Various chemical entities (functional groups) attached to the central moiety are responsible for their diverse range of biological properties. The development of the characterization of these plant metabolites and the enzymes involved in their biosynthesis is of an utmost priority to deliver enhanced advantages in terms of biological properties and productivity. Further, the incorporation of whole/partial metabolic pathways in the heterologous system and/or the overexpression of biosynthetic steps in homologous systems have both become alternative and lucrative methods over chemical synthesis in recent times. Moreover, in-depth research on alkaloid biosynthetic pathways has revealed numerous chemical modifications that occur during alkaloidal conversions. These chemical reactions involve glycosylation, acylation, reduction, oxidation, and methylation steps, and they are usually responsible for conferring the biological activities possessed by alkaloids. In this review, we aim to discuss the alkaloidal group of plant specialized metabolites and their brief classification covering major categories. We also emphasize the diversity in the basic structures of plant alkaloids arising through enzymatically catalyzed structural modifications in certain plant species, as well as their emerging diverse biological activities. The role of alkaloids in plant defense and their mechanisms of action are also briefly discussed. Moreover, the commercial utilization of plant alkaloids in the marketplace displaying various applications has been enumerated.

Synthesis and Biological Activity of Ferrocenyl and Ruthenocenyl Analogues of Etoposide: Discovery of a Novel Dual Inhibitor of Topoisomerase II Activity and Tubulin Polymerization

Two series of the ferrocenyl and ruthenocenyl analogues of etoposide bearing 1,2,3-triazolyl or aminoalkyl linker were synthesized and evaluated for their cytotoxic properties, influence on the cell cycle, ability to induce tubulin polymerization, and inhibition of topoisomerase II activity. We found that the replacement of the etoposide carbohydrate moiety with a metallocenyl group led to organometallic conjugates exhibiting differentiated antiproliferative activity. Biological studies demonstrated that two ferrocenylalkylamino conjugates were notably more active than etoposide, with submicromolar or low-micromolar IC₅₀ values towards SW620, etoposide-resistant SW620E, and methotrexate-resistant SW620M cancer cell lines. Moreover, the simplest ferrocenylmethylamino conjugate exerted dual inhibitory action against tubulin polymerization and topoisomerase II activity while other studied compounds affected only topoisomerase II activity.

Anticancer Potential of Betulonic Acid Derivatives

Clinical trials have evidenced that several natural compounds, belonging to the phytochemical classes of alkaloids, terpenes, phenols and flavonoids, are effective for the management of various types of cancer. Latest research has proven that natural products and their semisynthetic variants may serve as a starting point for new drug candidates with a diversity of biological and pharmacological activities, designed to improve bioavailability, overcome cellular resistance, and enhance therapeutic efficacy. This review was designed to bring an update regarding the anticancer potential of betulonic acid and its semisynthetic derivatives. Chemical derivative structures of betulonic acid including amide, thiol, and piperidine groups, exert an amplification of the in vitro anticancer potential of betulonic acid. With the need for more mechanistic and in vivo data, some derivatives of betulonic acids may represent promising anticancer agents.

Status and Challenges of Plant-Anticancer Compounds in Cancer Treatment

Nowadays, cancer is one of the deadliest diseases in the world, which has been estimated to cause 9.9 million deaths in 2020. Conventional treatments for cancer commonly involve mono-chemotherapy or a combination of radiotherapy and mono-chemotherapy. However, the negative side effects of these approaches have been extensively reported and have prompted the search of new therapeutic drugs. In this context, scientific community started to look for innovative sources of anticancer compounds in natural sources, including traditional plants. Currently, numerous studies have evaluated the anticancer properties of natural compounds derived from plants, both in vitro and in vivo. In pre-clinical stages, some promising compounds could be mentioned, such as the sulforaphane or different phenolic compounds. On the other hand, some phytochemicals obtained positive results in clinical stages and were further approved for cancer treatment, such as vinca alkaloids or the paclitaxel. Nevertheless, these compounds are not exempt of limitations, such as low solubility, restricted effect on their own, negative side-effects, etc. This review aims to compile the information about the current phytochemicals used for cancer treatment and also promising candidates, main action mechanisms and also reported limitations. In this sense, some strategies to face the limitations have been considered, such as nano-based formulations to improve solubility or chemical modification to reduce toxicity. In conclusion, although more research is still necessary to develop more efficient and safe phytochemical drugs, more of these compounds might be used in future cancer therapies.

Indoline-6-Sulfonamide Inhibitors of the Bacterial Enzyme DapE

Inhibitors of the bacterial enzyme dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE; EC 3.5.1.18) hold promise as antibiotics with a new mechanism of action. Herein we describe the discovery of a new series of indoline sulfonamide DapE inhibitors from a high-throughput screen and the synthesis of a series of analogs. Inhibitory potency was measured by a ninhydrin-based DapE assay recently developed by our group. Molecular docking experiments suggest active site binding with the sulfonamide acting as a zinc-binding group (ZBG).

Sophoridine exerts tumor-suppressive activities via promoting ESRRG-mediated β-catenin degradation in gastric cancer

Background

As a natural alkaloid product isolated from Sophora alopecuroides. L, Sophoridine reshapes gastric cancer immune microenvironment via inhibiting chemotaxis and M2 polarization of tumor-associated macrophages (TAMs). However, the exact effects and underlying mechanism of Sophoridine on gastric cancer cells remains poorly known.

Methods

The potential anti-tumor effects of Sophoridine on gastric cancer cell lines, including AGS and SGC7901 cells, were detected by CCK-8, EDU and colony forming assay, immunofluorescence, transwell assay, and flow cytometry. Molecular mechanisms of Sophoridine were investigated by siRNA transfection, nuclear/cytoplasmic extraction and western blot. The synergistic effects of Sophoridine with cisplatin on gastric cancer cells were further investigated in in vitro functional studies.

Results

Sophoridine exhibited potent tumor-suppressive activities in gastric cancer cells, including inhibition of proliferation, colony formulation, migration and invasion, as well as induction of apoptosis. In addition, we further showed that Sophoridine induced G2/M cell cycle arrest via inhibiting double-stranded DNA breaks repair and enhanced the efficacy of cisplatin in gastric cancer cells. Molecular studies further revealed that Sophoridine promoted β-catenin degradation by enhancing Estrogen-related receptor gamma (ESRRG) expression, but not depended on ubiquitination-proteasome pathway, either TRIM33-mediated (GSK3β-independent) or altered GSK3β activity, and thus exerted potent tumor-suppressive activities.

Conclusion

Sophoridine depends on targeting ESRRG/β-catenin pathway to exert tumor-suppressive activities in gastric cancer cells and enhances the anti-tumor effect of cisplatin. Our study provided the promising preclinical anti-tumor evidence for the potential application of Sophoridine against gastric cancer.

A review of research progress of antitumor drugs based on tubulin targets

Microtubules exist in all eukaryotic cells and are one of the critical components that make up the cytoskeleton. Microtubules play a crucial role in supporting cell morphology, cell division, and material transport. Tubulin modulators can promote microtubule polymerization or cause microtubule depolymerization. The modulators interfere with the mitosis of cells and inhibit cell proliferation. Tubulin mainly has three binding domains, namely, paclitaxel, vinca and colchicine binding domains, which are the best targets for the development of anticancer drugs. Currently, drugs for tumor therapy have been developed for these three domains. However, due to its narrow therapeutic window, poor selectivity, and susceptibility to drug resistance, it has severely limited clinical applications. The method of combined medication, the change of administration method, the modification of compound structure, and the research and development of new targets have all changed the side effects of tubulin drugs to a certain extent. In this review, we briefly introduce a basic overview of tubulin and the main mechanism of anti-tumor. Secondly, we focus on the application of drugs which developed based on the three domains of tubulin to various cancers in various fields. Finally, we further provide the development progress of tubulin inhibitors currently in clinical trials.

Synthetic Studies toward Dimeric Indole Alkaloids Based on Convergent Synthetic Strategy

The total syntheses of dimeric indole alkaloids, haplophytine, and T988s are described. These dimeric compounds comprising two structurally different indole units are ubiquitous in nature, and many possess pharmaceutically important activities. To realize an efficient chemical synthesis of these dimeric indole alkaloids, the establishment of convergent synthetic strategies and development of new coupling methods are indispensable. The linkage of two highly functionalized units at a late stage of the synthesis frequently induces synthetic problems such as chemoselectivity and steric repulsion. Moreover, although transition metal-catalyzed reactions are usually an effective method for the cross-coupling of two units, the application of these cross-coupling reactions to bond formation involving a sterically hindered C(sp³) is often difficult. Thus, even with precise modern synthetic methods, it is currently difficult to realize convergent syntheses of dimeric indole alkaloids possessing a quaternary carbon linking two units. To combat these synthetic problems, we developed a synthetic method to link two indole units using an Ag-mediated nucleophilic substitution reaction. In this review, we provide a detailed discussion of convergent synthetic strategies and coupling methods for dimeric indole alkaloids.

In Search of Panacea-Review of Recent Studies Concerning Nature-Derived Anticancer Agents

Cancers are one of the leading causes of deaths affecting millions of people around the world, therefore they are currently a major public health problem. The treatment of cancer is based on surgical resection, radiotherapy, chemotherapy or immunotherapy, much of which is often insufficient and cause serious, burdensome and undesirable side effects. For many years, assorted secondary metabolites derived from plants have been used as antitumor agents. Recently, researchers have discovered a large number of new natural substances which can effectively interfere with cancer cells’ metabolism. The most famous groups of these compounds are topoisomerase and mitotic inhibitors. The aim of the latest research is to characterize natural compounds found in many common foods, especially by means of their abilities to regulate cell cycle, growth and differentiation, as well as epigenetic modulation. In this paper, we focus on a review of recent discoveries regarding nature-derived anticancer agents.

[Care of advanced or metastatic bladder cancer in second line: A specific place for vinflunine]

Urothelial carcinoma of the bladder are rare but aggressive tumors with a high metastatic potential. The prognosis of these tumors has not drastically changed over the past 30 years, with an overall survival of less than two years in advanced or metastatic situations. Even though immune checkpoints inhibitors have changed this picture, it is beneficial for less than 30% of patients and there is no reliable biomarkers to identify this specific population of responders. Vinflunine is a vinca-alkaloid that was specifically developed as second line treatment post-platinum. As of today, it is the sole anticancer agent for which clinical trials have been pushed to phase III and that was approved for patients in good conditions. Unfortunately, it has been withdrawn from the list of reimbursed drugs, which impairs its prescription. Based on the results of phase III clinical trials with immunotherapies, this review provides the reader with argumentations in favor of patients' and clinicians' request to reimburse vinflunine for the treatment of advanced or metastatic urothelial carcinoma of the bladder.

Solventless and Metal-free Regioselective Hydrofluorination of Functionalized Alkynes and Allenes: An Efficient Protocol for the Synthesis of gem-Difluorides

The combination of two easily handled, highly acidic liquid HF complex reagents, DMPU-12HF and KHSO4-13HF, generated a highly acidic fluorination system that facilitated exclusive Markovnikov addition of HF to widely functionalized alkynes, including alkyne tethered drugs, or allenes to produce gem-difluorides with high atom economy, and with an easy workup.

Anti-tubulin agents of natural origin: Targeting taxol, vinca, and colchicine binding domains

Microtubules are a protein which is made of α- and β-heterodimer. It is one of the main components of the cell which play a vital role in cell division especially in G2/M-phase. It exists in equilibrium dynamic of polymerization and depolymerization of α- and β-heterodimer. It is one of the best targets for developing anti-cancer drugs. Various natural occurring molecules are well known for their anti-tubulin effect such as vinca, paclitaxel, combretastatin, colchicine etc. These microtubule-targeted drugs are acted through two processes (i) inhibiting depolymerization of tubulin (tubulin stabilizing agents) and (ii) inhibiting polymerization of tubulin (tubulin destabilizing agents). Now days, various binding domains have been explore through which these molecules are binding to tubulin but the three major binding domain of tubulin are taxol, vinca and colchicine binding domain. The present article mainly focus on the classification of various naturally occurring compounds on the basis of their inhibition processes (depolymerization and polymerization) and the site of interaction (targets taxol, vinca and colchicine binding domain) which has been hitherto reported. By placing all the naturally occurring taxol, vinca and colchicine binding site analogues at one place makes a better understanding of the tubulin interactions with known natural tubulin binders that would helps in the discovery of new and potent natural, semi-synthetic and synthetic analogues for treating cancer.

Towards modern anticancer agents that interact with tubulin

Tubulin is the primary target of an ever growing number of natural, semisynthetic and synthetic products as potential anticancer agents. The mechanisms of interaction of these molecules with tubulin are varied. These drug classes have shown to inhibit effectively several cancer types with IC₅₀ from midmicromolar to low nanomolar concentrations. However, some limiting obstacles still remain, such as the development of multidrug resistance and cytotoxicity. We have reviewed recent advances in different classes of tubulin binding agents, including colchicine site agents, Vinca alkaloids, tryprostatins, moroidin, hemiasterlin, diazonamide, taxanes, epothilones and laulimalide.

Adverse drug reactions of anticancer drugs derived from natural sources

Cancer, a life threatening disease adversely affects huge population worldwide. Naturally derived drug discovery has emerged as a potential pathway in search of anticancers. Natural products-based drugs are generally considered safe, compared to their synthetic counterparts. A systematic review on adverse drugs reactions (ADRs) of the anticancer natural products has not been performed till date. We reviewed anticancer drugs, derived from plants, microbes and marine sources with their mechanistic action and reported ADRs. PubMed, ScienceDirect and Scopus were searched through Boolean information retrieval method using keywords "natural products", "cancer", "herbal", "marine drugs" and "adverse drug reaction". We documented ADRs of natural products based anticancer agents, mechanisms of action and chemical structures. It was observed that majority of the natural products based anticancer drugs possess ample adverse effects, dominantly hematological toxicities, alopecia, neurotoxicity and cardiotoxicity. These findings deviate from the preconceived notion about safer nature of herbal drugs. We also came across some anti-cancer natural products with less/no reported adverse events like Cabazitaxel and Arglabin. Comprehensive pharmacovigilance studies are needed to report ADRs and thereby predicting safety of anti-cancer drugs, either originated from natural sources or chemically synthesized.

Safety of Vinflunine in Patients with Advanced Urothelial Carcinoma Refractory to Platinum-based Chemotherapy: A Prospective Pilot Study

BACKGROUND

Several single chemotherapeutic agents have been evaluated as the second-line treatment of advanced urothelial carcinoma. Despite encouraging efficacy outcomes, toxicity has often led to dose modifications or discontinuation. We aimed to assess the safety of vinflunine in a particular population of advanced transitional cell carcinoma of urothelium (TCCU), that were exposed to the previous toxicity of chemotherapy.

METHODS

This is an open-label, prospective, single-center pilot study to evaluate the response rate and safety profile of vinflunine in patients with advanced TCCU. It was planned to enroll 25 evaluable patients. Eligible patients are those with progressive disease after first-line platinum-based regimen for advanced or metastatic disease.

RESULTS

The study was prematurely closed due to two sudden deaths that were judged by the review board as treatment-related. Only ten patients were evaluated and received at least one cycle of vinflunine. All but one were male and seven underwent radical surgery. Eight had a distant metastasis (mainly lung and/or liver). Disease control rate was 40%, four patients had a partial response with median duration of response of 3.5 months. The median overall survival was 3.2 months (95% CI:1.67- 4.73). There were three serious adverse events namely two sudden deaths and one grade 4 thrombocytopenia. Nine grade 3/4 adverse events occurred. The most common all-grade adverse events were fatigue (50%), constipation (40%) and vomiting (40%). Moreover, grade 3 fatigue occurred in 30% of patients. Only one patient, who achieved PR for 5 months, was fit to receive further cytotoxic chemotherapy.

CONCLUSION

The activity of vinflunine in advanced urothelial carcinoma came at the expense of its safety. The use of vinflunine has to be limited to the selected group of patients. However, this is a single institute experience in a limited number of patients.

Inhibit or Evade Multidrug Resistance P-Glycoprotein in Cancer Treatment

Multidrug resistance (MDR) is a major cause of failure in cancer chemotherapy. P-glycoprotein (P-gp), a promiscuous drug efflux pump, has been extensively studied for its association with MDR due to overexpression in cancer cells. Several P-gp inhibitors or modulators have been investigated in clinical trials in hope of circumventing MDR, with only limited success. Alternative strategies are actively pursued, such as the modification of existing drugs, development of new drugs, or combination of novel drug delivery agents to evade P-gp-dependent efflux. Despite the importance and numerous studies, these efforts have mostly been undertaken without a priori knowledge of how drugs interact with P-gp at the molecular level. This review highlights and discusses progress toward and challenges impeding drug development for inhibiting or evading P-gp in the context of our improved understanding of the structural basis and mechanism of P-gp-mediated MDR.