apaziquone and Urinary-Bladder-Neoplasms

Apaziquone is an interesting drug for intravesical use in patients with nonmuscle invasive bladder cancer; however, more research is needed to prove its actual benefit. Although the apaziquone trials demonstrate the potential of this new drug, the singular phase 3 trials did not reach their primary endpoint. To date, no new trials are recruiting, so the development of apaziquone seems to have stopped.

Topics: Administration, Intravesical; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Humans; Indolequinones; Neoplasm Invasiveness; Treatment Outcome; Urinary Bladder Neoplasms

Chemoablation is an emerging treatment for urothelial carcinomas. This review provides an overview of the evidence for intracavitary chemoablation in the treatment of urothelial carcinomas. The benefits of such agents include a reduction in morbidity and diseased organ preservation. While numerous agents have shown promise, research is limited due to small patient cohorts, varying follow-up, and no standardized methodology to assess response. Therefore, to date, chemoablation has not been widely adopted. This may change as a novel mitomycin formulation has recently been approved for treating low-grade upper tract urothelial carcinoma. Future studies are ongoing which evaluate other promising chemoablation options in urothelial carcinoma.

Topics: Administration, Intravesical; Antineoplastic Agents; Aziridines; BCG Vaccine; Carcinoma, Transitional Cell; Clinical Trials as Topic; Cystoscopy; Deoxycytidine; Epirubicin; Ethanol; Forecasting; Gemcitabine; Humans; Indolequinones; Injections, Intralesional; Interferon-alpha; Interleukin-2; Mitomycin; Urinary Bladder Neoplasms; Urothelium

As our molecular understanding of bladder cancer continues to advance, more and more novel agents are entering clinical trials across the spectrum of bladder cancer stages. The clinical trial activity for non-muscle invasive bladder cancer (NMIBC) has been boosted further by the evolution of specific disease states that set more uniform inclusion criteria for clinical trial design. Here, we aimed to review the current clinical trials landscape in non-muscle invasive bladder cancer with respect to these disease states.. Most active clinical trials focus on high-risk NMIBC in either the BCG-naïve or BCG-unresponsive setting. Strict criteria to define the disease state and a clear pathway to drug registration have encouraged trials for patients with BCG-unresponsive NMIBC. The most promising potential breakthroughs for BCG-naïve patients include alternative BCG strains, immune-priming with intradermal BCG vaccination, and systemic immune checkpoint blockade. The latter therapy is also being actively investigated in multiple trials in BCG-unresponsive NMIBC, along with novel viral agents such as INSTILADRIN (nadofaragene firadenovec) and targeted agents such as oportuzumab monatox. After many years of relative stagnation, multiple new therapies currently under investigation in well-designed clinical trials appear poised for routine clinical implementation in the near future. These therapies should dramatically improve the outcome of patients with NMIBC. We can look forward to the challenges of biomarker-driven drug selection, optimal drug sequencing, and rational combination therapies.

Topics: Adjuvants, Immunologic; Administration, Intravesical; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Antineoplastic Agents, Immunological; Aziridines; BCG Vaccine; Carcinoma, Transitional Cell; Chemotherapy, Adjuvant; Clinical Trials as Topic; Combined Modality Therapy; Humans; Indolequinones; Injections, Intradermal; Mitomycin; Muscle, Smooth; Neoplasm Invasiveness; Polysaccharides, Bacterial; Proteins; Recombinant Fusion Proteins; Tamoxifen; Typhoid-Paratyphoid Vaccines; Urinary Bladder Neoplasms; Urologic Surgical Procedures

Topics: Administration, Intravesical; Animals; Antineoplastic Agents; Aziridines; Humans; Indolequinones; Neoplasm Invasiveness; Neoplasm Recurrence, Local; Urinary Bladder Neoplasms

Bladder cancer is nowadays a common tumor. Non-muscle invasive bladder cancer (NMIBC) has still chances of recurrence and progression in spite of surgery and adjuvant treatments. New therapies are being developed to reduce these percentages with less adverse effects - Apaziquone (EO9) is an example. Areas covered: A literature search has been performed using Pubmed, UpToDate and Google verified information (mainly from Food and Drug Administration and Spectrum Pharmaceutics websites). We have included data from the most representative clinical trials and reviews published. Expert opinion: Apaziquone is considered a promising chemical agent if applied intravesically due mainly to its pharmacodynamics and safety profile. There is evidence for this with respect to adjuvant chemo ablative therapy and as a post-transurethral resection of bladder (TURB) single-dose regimen. As a result, new clinical phase III trials are needed both to evaluate its efficacy as an adjuvant therapy in the spectrum from intermediate- to high-risk non-muscle invasive bladder cancer and to select the most appropriate candidates and treatment schedule. As a conclusion, Apaziquone is a good candidate to become a better alternative as an adjuvant therapy for the treatment of NMIBC in the near future.

Topics: Administration, Intravesical; Antineoplastic Agents; Aziridines; Chemotherapy, Adjuvant; Combined Modality Therapy; Disease Progression; Humans; Indolequinones; Neoplasm Recurrence, Local; Urinary Bladder Neoplasms

EO9 (Apaziquone) is a bioreductive drug that has a chequered history. It underwent clinical trial but failed to show activity in phase II clinical trials when administered i.v. Poor drug delivery to tumours caused by a combination of rapid pharmacokinetic elimination and poor penetration through avascular tissue were the major factors responsible for EO9's poor efficacy. Based upon an understanding of why EO9 failed, a further clinical trial against patients with superficial transitional cell carcinoma of the bladder was conducted. The rationale for this was that intravesical administration directly into the bladder would circumvent the drug delivery problem, and any drug reaching the blood supply would be rapidly cleared thereby reducing the risk of systemic exposure. EO9 was well tolerated, and clinical activity against marker lesions was recorded in both phase I and II clinical trials. This article charts the pharmacological history of EO9 and discusses the potential implications that 'the EO9 story' has for the development of other loco-regional therapies.

Topics: Administration, Intravesical; Animals; Antineoplastic Agents; Area Under Curve; Aziridines; Carcinoma, Non-Small-Cell Lung; Carcinoma, Transitional Cell; Disease Models, Animal; Drug Delivery Systems; Humans; Immunohistochemistry; Indolequinones; Lung Neoplasms; Treatment Failure; Urinary Bladder; Urinary Bladder Neoplasms

Urothelial carcinoma of the bladder is a disease prone to recurrence. A new cytotoxic drug, apaziquone, is an analog of mitomycin C. Given via intravesical instillations it has the ability to specifically target cancer cells.. This article reviews the discovery and pharmacological properties of the agent and the first steps of its application in human disease. The poor performance of the drug as a systemic medication is discussed along with in vivo and in vitro studies that have led to current intravesical applications with encouraging results. In detail the limited number of clinical studies on the drug and compare them with relevant series on currently used agents. In addition, different strategies to enhance the efficacy of other agents are discussed and possible application of this experience to apaziquone is proposed.. Apaziquone is a promising local agent for the treatment and prevention of recurrent urothelial carcinoma of the bladder. The limited number of Phase II studies has demonstrated potency and relatively low toxicity. In light of the dearth of randomized controlled trials, Phase III studies are urgently needed before any conclusive pronouncements on this agent can be made.

Topics: Administration, Intravesical; Animals; Antineoplastic Agents; Aziridines; Carcinoma; Humans; Indolequinones; Urinary Bladder Neoplasms

To describe clinical needs in non-muscle invasive bladder cancer (NMIBC) and review the potential of apaziquone in this respect.. Epidemiology and clinical practice in NMIBC, as well as new drugs and strategies are reviewed.. Bladder cancer is a heterogeneous and frequent disease. Clinical risk factors help in determining additional therapy after initial resection. However, current treatments have clear limitations with regard to efficacy and/or toxicity. New drugs and strategies have been tested recently and are in (pre)clinical use. Intravesical apaziquone (EOquin) is a new drug. It has theoretical advantages for intravesical use, has proven safety and is presently under further clinical evaluation.. Apaziquone is a promising drug for intravesical use in patients with NMIBC.

Topics: Animals; Aziridines; Drug Evaluation, Preclinical; Drug Tolerance; Humans; Indolequinones; Muscle Neoplasms; Urinary Bladder Neoplasms

We studied the safety and efficacy of multiple adjuvant apaziquone instillations in patients with high risk nonmuscle invasive bladder cancer.. Patients with high risk nonmuscle invasive urothelial carcinoma of the bladder underwent transurethral resection of all bladder tumor(s), and received 6 weekly adjuvant intravesical apaziquone instillations of 4 mg in 40 ml. Patients with carcinoma in situ received 3 further maintenance instillations at months 3, 6 and 12. Followup consisted of cystoscopy, urine cytology and observation of adverse events every 3 months for 18 months.. A total of 53 patients were enrolled in the study. Although all patients were high risk according to the definitions used when the study was initiated, according to most recent guideline criteria, 80% and 20% of these patients would now be considered intermediate and high risk for recurrence, and 50% and 44% would be considered intermediate and high risk for progression, respectively. Intent to treat analysis of 49 patients with papillary tumors showed recurrent tumors in 34.7% and 44.9% at 12 and 18 months, respectively. One patient had progression to T2 or greater urothelial carcinoma after 9 months. There were 4 patients with carcinoma in situ who had complete responses at 3 months but discontinued treatment due to cystitis, recurrent papillary disease, urinary incontinence and dysuria. Most other side effects were mild (grade 1 to 2).. Adjuvant intravesical instillations of apaziquone are generally well tolerated. The recurrence rates of 34.7% after 12 months and 44.9% after 18 months in these patients can be considered encouraging, and warrant further study.

Topics: Administration, Intravesical; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Chemotherapy, Adjuvant; Female; Humans; Indolequinones; Male; Middle Aged; Neoplasm Invasiveness; Prospective Studies; Risk Factors; Urinary Bladder Neoplasms

To study the time-to-recurrence and duration of response in non-muscle invasive bladder cancer (NMIBC) patients, with a complete ablative response after intravesical apaziquone instillations.. Transurethral resection of bladder tumour(s) (TURBT) was performed in patients with multiple pTa-T1 G1-2 urothelial cell carcinoma (UCC) of the bladder, with the exception of one marker lesion of 0.5-1.0 cm. Intravesical apaziquone was administered at weekly intervals for six consecutive weeks, without maintenance instillations. A histological confirmed response was obtained 2-4 weeks after the last instillation. Routine follow-up (FU) was carried out at 6, 9, 12, 18 and 24 months from the first apaziquone instillation.. At 3 months FU 31 of 46 patients (67.4%) had a complete response (CR) to ablative treatment. Side-effects on the long-term were only mild. Two CR patients dropped out during FU. On intention-to-treat (ITT) analysis 49.5% of the CR patients were recurrence-free at 24 months FU, with a median duration of response of 18 months. Of 15 no response (NR) patients, only two received additional prophylactic instillations after TURBT. On ITT-analysis 26.7% of the NR patients were recurrence-free (log rank test, P = 0.155). The overall recurrence-free survival was 39% (18 of 46 patients) at 24 months FU.. The CR of the marker lesion in 67% of patients was followed by a recurrence-free rate of 56.5% at 1-year FU, and 49.5% at 2-year FU. These long-term results are good in comparison with the results of other ablative studies.

Topics: Administration, Intravesical; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Female; Follow-Up Studies; Humans; Indolequinones; Male; Middle Aged; Neoplasm Invasiveness; Prospective Studies; Time Factors; Urinary Bladder Neoplasms

We studied the safety, tolerability and pharmacokinetics of a single immediate post-transurethral resection intravesical instillation of apaziquone for patients with nonmuscle invasive bladder cancer.. Patients with cTa-T1, G1-G2 urothelial cell carcinoma of the bladder underwent transurethral resection of bladder tumor(s) followed by a single intravesical instillation of apaziquone 4 mg/40 ml for 1 hour within 6 hours of transurethral bladder tumor resection. Adverse events and safety parameters were assessed on days 8 and 15 after transurethral bladder tumor resection. Blood samples were drawn before and during the instillation for pharmacokinetic analyses. The first 10 patients with pTa-T1, G1-G2 nonmuscle invasive bladder cancer were also evaluated by cystoscopy 3 months after treatment to determine mucosal healing.. Of 20 patients receiving apaziquone 13 (65%) reported 35 adverse events, mostly grade 1 to 2. Eight patients (40%) reported 13 adverse events related to treatment, in particular dysuria, hematuria, bladder spasm, abdominal pain, asthenia and postoperative urinary retention. Three grade 3 and 1 grade 4 event(s) occurred, but these were considered unrelated to treatment. No other significant clinical changes were observed. Apaziquone and the active metabolite EO5a were not detected with pharmacokinetic analyses at any point of time. After 3 months no evidence of impaired mucosal healing was observed.. A single immediate post-transurethral bladder tumor resection instillation of apaziquone was well tolerated with an expected good safety profile. Apaziquone and its metabolite EO5a were not detected systemically with pharmacokinetic analyses. These results have lead to further study of a single immediate instillation of apaziquone.

Topics: Administration, Intravesical; Aged; Aged, 80 and over; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Combined Modality Therapy; Female; Humans; Indolequinones; Male; Middle Aged; Neoplasm Invasiveness; Prospective Studies; Time Factors; Urinary Bladder Neoplasms

The quinone based bioreductive drug apaziquone (EO9) failed to demonstrate efficacy in previous phase II studies following intravenous administration. We determined the dose of apaziquone that can be safely administered intravesically and explored its activity for superficial bladder transitional cell carcinoma.. Six patients with multifocal, Ta/T1 and G1/G2 transitional cell carcinoma of the bladder received escalating doses of apaziquone formulated as EOquintrade mark (0.5 mg/40 ml up to 16 mg/40 ml) weekly for 6 weeks. A further 6 patients received weekly apaziquone at the highest nontoxic dose established. Pharmacokinetic parameters were determined in urine and blood, and the pharmacodynamic markers NQO1 (reduced nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase-1) and glucose transporter 1 were also characterized. Efficacy was determined against a marker lesion.. Local toxicity (grades 2 and 3 dysuria, and hematuria) was observed at doses of 8 mg/40 ml and above but 4 mg/40 ml was well tolerated with no systemic or local side effects. Apaziquone in urine increased linearly with the dose but no apaziquone was detected in plasma. In 8 of 12 patients complete macroscopic and histological disappearance of the marker lesion occurred. A correlation between response and NQO1 and/or glucose transporter 1 expression could not be established.. Intravesical administration of 4 mg/40 ml apaziquone was well tolerated and had ablative activity against superficial bladder cancer marker lesions.

Topics: Administration, Intravesical; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Cohort Studies; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Indolequinones; Male; Middle Aged; Pilot Projects; Treatment Outcome; Urinary Bladder Neoplasms

We studied the ablative activity of intravesical apaziquone (EOquin) on a papillary marker tumor and determined the incidence of side effects.. A total of 46 patients with multiple pTa or pT1 bladder tumors underwent visible lesion resection except for 1 marker tumor. Patients were then treated with 6 instillations of apaziquone at weekly intervals. The response was determined 2 to 4 weeks after the last instillation.. One patient withdrew informed consent and refused the last treatment due to side effects. A histologically proven complete response was seen in 30 patients. Progression to invasive stage was not observed. Local side effects in this study were comparable to those due to other chemotherapy instillations, such as mitomycin C and epirubicin, but less severe and less frequent compared to those of bacillus Calmette-Guerin instillations.. The histological complete response rate after 6 consecutive instillations of apaziquone in patients with superficial bladder cancer was 67% (95% CI 51 to 80). Local side effects were comparable to side effects due to other chemotherapy instillations.

Topics: Administration, Intravesical; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aziridines; Carcinoma, Transitional Cell; Cohort Studies; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Indolequinones; Male; Middle Aged; Treatment Outcome; Urinary Bladder Neoplasms

Despite positive responses in phase II clinical trials, the bioreductive prodrug apaziquone failed to achieve statistically significant activity in non-muscle invasive bladder cancer in phase III trials. Apaziquone was administered shortly after transurethral resection and here we test the hypothesis that haematuria inactivates apaziquone.. HPLC analysis was used to determine the ability of human whole blood to metabolise apaziquone ex vivo. An in vitro model of haematuria was developed and the response of RT112 and EJ138 cells following a 1-h exposure to apaziquone was determined in the presence of urine plus or minus whole blood or lysed whole blood.. HPLC analysis demonstrated that apaziquone is metabolised by human whole blood with a half-life of 78.6 ± 23.0 min. As a model for haematuria, incubation of cells in media containing up to 75% buffered (pH 7.4) urine and 25% whole blood was not toxic to cells for a 1-h exposure period. Whole blood (5% v/v) significantly (p < 0.01) reduced the potency of apaziquone in this experimental model. Lysed whole blood also significantly (p < 0.05) reduced cell growth, although higher concentrations were required to achieve an effect (15% v/v).. The results of this study demonstrate that haematuria can reduce the potency of apaziquone in this experimental model. These findings impact upon the design of further phase III clinical trials and strongly suggest that apaziquone should not be administered immediately after transurethral resection of non-muscle invasive bladder cancer when haematuria is common.

Topics: Antineoplastic Agents; Aziridines; Cell Line, Tumor; Chromatography, High Pressure Liquid; Half-Life; Hematuria; Humans; In Vitro Techniques; Indolequinones; Research Design; Urinary Bladder Neoplasms

Previous studies have demonstrated that intravesical administration of apaziquone (EOquin) has ablative activity against superficial bladder cancer marker lesions with 8 out of 12 complete responses recorded. We present a comparison between the rates of tumor recurrence before and after treatment with apaziquone.. The rate of tumor recurrence after treatment with apaziquone was compared with each patient's historical record of recurrences obtained from a retrospective analysis of the patients' case notes. The time to each recurrence event before apaziquone treatment and the time to the first recurrence after apaziquone treatment were recorded, and the data were analyzed using a population-averaged linear regression model using Stata Release, version 9.2, software.. Of the eight complete responses obtained in the Phase I study, tumor recurrence occurred in 4 patients and the remaining 4 patients remained disease free after a median follow-up of 31 months. The time to the first recurrence after apaziquone treatment was significantly longer (P <0.001) compared with the historical pattern and recurrence interval before apaziquone. Before apaziquone instillation, the mean +/- SE recurrence rate and tumor rate per year was 1.5 +/- 0.2 and 4.8 +/- 1.2, respectively, and these decreased to 0.6 +/- 0.25 and 1.5 +/- 0.8, respectively, after apaziquone treatment (P <0.05).. The results of this study indicate that early recurrences after treatment with apaziquone are infrequent and the interval to recurrence is significantly greater compared with the historical recurrence times for these patients. Larger prospective randomised trials are warranted to confirm these results.

Topics: Administration, Intravesical; Aziridines; Biopsy, Needle; Carcinoma, Transitional Cell; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Follow-Up Studies; Humans; Immunohistochemistry; Indolequinones; Male; Neoplasm Recurrence, Local; Neoplasm Staging; Probability; Retrospective Studies; Risk Assessment; Survival Analysis; Treatment Outcome; Urinary Bladder Neoplasms

EO9 (apaziquone) is a novel, promising anticancer agent, which is currently being investigated for the intravesical treatment of bladder cancer. EO9 contains a highly reactive aziridine ring in its structure that limits its chemical stability in acidic aqueous solutions. The stability of the pharmaceutically formulated EO9 in human urine, including the effects of several parameters such as temperature, buffer strength and pH have been investigated. Urine extracts were analyzed by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry (HPLC-MS/MS) using a TurboIonspray interface and positive-ion multiple reaction monitoring. EO9 was unstable in urine at 43 degrees C during the instillation for longer than 1 h. However, the drug was stable in human urine for 3 h at 37 degrees C. EO9 is stable in urine stabilized with TRIS buffer (pH 9.0; 5 mM) for up to three freeze/thaw cycles at -20 and -70 degrees C and 3 months of storage at -70 degrees C. The results also illustrated that with the lower pH in urine, EO9 became more unstable. Furthermore, a new degradation product of EO9 was discovered and successfully identified as EO9-Cl. The outcomes of these stability experiments will be implemented to insure proper sample handling at the clinical sites, transport, storage, and sample handling during analysis in the forthcoming preclinical studies of EO9 in superficial bladder cancer, supported by bioanalysis and pharmacokinetic monitoring.

Topics: Antineoplastic Agents; Aziridines; Buffers; Calibration; Chromatography, High Pressure Liquid; Humans; Hydrogen-Ion Concentration; Indolequinones; Mass Spectrometry; Reference Standards; Specimen Handling; Temperature; Urinary Bladder Neoplasms

A bladder instillation of EO-9 (EOquin) is currently used in phase II clinical trials for the treatment of superficial bladder cancer. Three alternative formulations were developed to improve its pharmaceutical properties and clinical acceptability. Freeze-dried products composed of EO-9, 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD), tri(hydroxymethyl) aminomethane (Tris), and sodium bicarbonate (NaHCO(3)) were tested. Selection of one formulation for further development was based on stability studies. These studies comprised stability of the freeze-dried products, stability after reconstitution and dilution and stability during bladder instillation in an experimental set-up. The stability study of the freeze-dried products showed that the formulation composed of EO-9/HPbetaCD/Tris (4/600/1mg/vial) was most stable. After reconstitution and dilution all products were stable for at least 8h. The product composed of EO9/HPbetaCD/NaHCO(3) (4/600/20mg/vial) was the least stable product both as freeze-dried formulation and after reconstitution and dilution. The bladder instillation simulation experiment showed that all products were stable when mixed with urine of pH 8 and unstable in urine of pH 4 and 6. The degradation products formed in urine were EO-5a and EO-9-Cl. Based on these results, the product composed of EO-9/HPbetaCD/Tris (4/600/1mg/vial) was selected for further pharmaceutical development.

Topics: Aziridines; Computer Simulation; Drug Stability; Drug Storage; Indolequinones; Models, Biological; Urinary Bladder Neoplasms

Hyperthermia combined with chemotherapy is not a novel cancer treatment. However, the working mechanism of this combination therapy is not fully understood. In the current in vitro study we investigated the differences in cytotoxicity of 4 chemotherapeutic agents at 37C or 43C.. The human transitional cell carcinoma cell lines used were RT4, RT112, 253J and T24. Cells were seeded in 96-well microtiter plates. After 24 hours cells were treated for 60 minutes with increasing concentrations of mitomycin C, epirubicin, gemcitabine and EO9 at a temperature of 37C or 43C. After treatment cells were rinsed 3 times and left for 24 hours in the incubator at 37C. The influence of chemotherapy and temperature on cell survival was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide) assay.. Decreased cell proliferation with increasing concentrations of chemotherapeutic agents was demonstrated. EO9 proved to be the most potent agent at each temperature. Hyperthermia alone did not demonstrate decreased cell proliferation. However, a synergistic effect on decreased cell proliferation was demonstrated in all cell lines and chemotherapeutic agents used, although each had a maximum at a different chemotherapy concentration and to a different extent. Synergism was most obvious in cell lines treated with low dose epirubicin.. Synergism with hyperthermia and chemotherapy was clearly demonstrated for epirubicin, EO9, mitomycin C and to a lesser extent gemcitabine. Hyperthermia alone did not cause decreased cell proliferation. Synergism was most prominent with low drug doses and the most potent drug used in this in vitro study was EO9.

Topics: Antibiotics, Antineoplastic; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Aziridines; Carcinoma, Transitional Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Coloring Agents; Combined Modality Therapy; Deoxycytidine; Epirubicin; Gemcitabine; Humans; Hyperthermia, Induced; Indolequinones; Mitomycin; Tetrazolium Salts; Thiazoles; Urinary Bladder Neoplasms

The indolequinone EO9 demonstrated good preclinical activity but failed to show clinical efficacy against a range of tumours following intravenous drug administration. A significant factor in EO9's failure in the clinic has been attributed to its rapid pharmacokinetic elimination resulting in poor drug delivery to tumours. Intravesical administration of EO9 would circumvent the problem of drug delivery to tumours and the principal objective of this study is to determine whether or not bladder tumours have elevated levels of the enzyme NQO1 (NAD(P)H:quinone oxidoreductase) which plays a key role in activating EO9 under aerobic conditions. Elevated NQO1 levels in human bladder tumour tissue exist in a subset of patients as measured by both immunohistochemical and enzymatic assays. In a panel of human tumour cell lines, EO9 is selectively toxic towards NQO1 rich cell lines under aerobic conditions and potency can be enhanced by reducing extracellular pH. These studies suggest that a subset of bladder cancer patients exist whose tumours possess the appropriate biochemical machinery required to activate EO9. Administration of EO9 in an acidic vehicle could be employed to reduce possible systemic toxicity as any drug absorbed into the blood stream would become relatively inactive due to an increase in pH.

Topics: Antineoplastic Agents; Aziridines; Humans; Hydrogen-Ion Concentration; Immunohistochemistry; Indolequinones; Indoles; Quinone Reductases; Substrate Specificity; Urinary Bladder; Urinary Bladder Neoplasms