Intravesical Gemcitabine: A Phase 1 and Pharmacokinetic Study

Evaluation of toxicities for intravesical drugs in phase 1 bladder cancer trials

BACKGROUND

Improving clinical trial design is important for optimizing approval of safe and effective drugs. Phase 1 clinical trials seek to determine phase 2 doses by investigating predefined dose-limiting toxicities. Traditional definitions of dose-limiting toxicity may not be applicable to intravesical therapies for bladder cancer. This study compared the frequency of dose-limiting toxicities and serious adverse events in bladder cancer trials for intravesical therapies to other routes of administration.

METHODS

Studies were abstracted from ClinicalTrials.gov and reconciled with a PubMed search. Primary and secondary end points were predefined before data abstraction, and the primary end point was subject-level dose-limiting toxicity rate. Fisher exact tests were performed with p < .05 designated as significant.

RESULTS

Eighteen intravesical studies and 24 studies with other routes of administration (the per os/intravenous/intramuscular [PO/IV/IM] group) were identified. Dose-limiting toxicities were reported in 38.9% of intravesical studies, affecting 3.29% of subjects, compared with 30.0% of PO/IV/IM studies representing 4.19% of subjects (p = .52 for study-level and p = .60 for subject-level comparisons). Serious adverse events occurred in 53.9% of intravesical studies in 10.3% of subjects versus 91.0% of studies reporting serious adverse events affecting 41.4% of subjects in the PO/IV/IM group (p = .03 for subject-level and p < .0001 for study-level comparisons).

CONCLUSIONS

There was no difference in subject-level dose-limiting toxicity rate between intravesical and PO/IV/IM bladder cancer trials. The serious adverse event rate was lower in the intravesical group. Heterogeneity of dose-limiting toxicity definition may affect interpretation of toxicity in phase 1 bladder cancer clinical trials studying different routes of administration.

LAY SUMMARY

Bladder cancer is a common cancer type that may be treated with therapies that are instilled into the bladder and act locally, called intravesical therapies. This study used publicly available regulatory data from early phase clinical trials to determine whether measures of tolerability used in clinical trials are applicable to intravesical therapies for bladder cancer.

Adjuvant therapies for non-muscle-invasive bladder cancer: advances during BCG shortage

Non-muscle-invasive bladder cancer (NMIBC) represents a significant global therapeutic challenge, particularly in the era of Bacillus Calmette-Guérin (BCG) shortage. High-risk NMIBC can progress to muscle invasive or metastatic disease in 25% of patients. Optimal treatment selection, according to risk stratification, is imperative. International guidelines slightly differ in their categorisation of low, intermediate and high-risk NMIBC. Nonetheless, a single post-operative instillation of chemotherapy with Mitomycin C (MMC) or Gemcitabine improves relapse-free survival (RFS) in low-risk NMIBC. Induction and maintenance intravesical BCG remains the historical gold standard for patients with intermediate or high-risk NMIBC. However, clinicians may be forced to consider alternatives given the current BCG shortage. Both intravesical MMC and Gemcitabine have been associated with similar efficacy to BCG, albeit in smaller studies. MMC may also be manipulated using a variety of methods to potentiate its effects. BCG treatment delivery may also be modified without affecting efficacy through dose reduction and abbreviation or omission of maintenance therapy. Preliminary data also highlight that directly proceeding to radical cystectomy may not adversely affect long-term quality of life measures. Access to new systemic and intravesical therapies must be prioritised for patients with BCG recurrent or unresponsive disease. When used in conjunction with molecularly defined biomarkers, these agents herald the potential for improved survival outcomes and alleviation of the current BCG shortage.

Knockdown of RRM1 with Adenoviral shRNA Vectors to Inhibit Tumor Cell Viability and Increase Chemotherapeutic Sensitivity to Gemcitabine in Bladder Cancer Cells

RRM1-an important DNA replication/repair enzyme-is the primary molecular gemcitabine (GEM) target. High RRM1-expression associates with gemcitabine-resistance in various cancers and RRM1 inhibition may provide novel cancer treatment approaches. Our study elucidates how RRM1 inhibition affects cancer cell proliferation and influences gemcitabine-resistant bladder cancer cells. Of nine bladder cancer cell lines investigated, two RRM1 highly expressed cells, 253J and RT112, were selected for further experimentation. An RRM1-targeting shRNA was cloned into adenoviral vector, Ad-shRRM1. Gene and protein expression were investigated using real-time PCR and western blotting. Cell proliferation rate and chemotherapeutic sensitivity to GEM were assessed by MTT assay. A human tumor xenograft model was prepared by implanting RRM1 highly expressed tumors, derived from RT112 cells, in nude mice. Infection with Ad-shRRM1 effectively downregulated RRM1 expression, significantly inhibiting cell growth in both RRM1 highly expressed tumor cells. In vivo, Ad-shRRM1 treatment had pronounced antitumor effects against RRM1 highly expressed tumor xenografts (p < 0.05). Moreover, combination of Ad-shRRM1 and GEM inhibited cell proliferation in both cell lines significantly more than either treatment individually. Cancer gene therapy using anti-RRM1 shRNA has pronounced antitumor effects against RRM1 highly expressed tumors, and RRM1 inhibition specifically increases bladder cancer cell GEM-sensitivity. Ad-shRRM1/GEM combination therapy may offer new treatment options for patients with GEM-resistant bladder tumors.

Gemcitabine hydrochloride microspheres used for intravesical treatment of superficial bladder cancer: a comprehensive in vitro/ex vivo/in vivo evaluation

INTRODUCTION

Bladder cancer is responsible for more than 130,000 deaths annually worldwide. Intravesical delivery of chemotherapeutic agents provides effective drug localization to the target area to reduce toxicity and increase efficacy. This study aimed to develop an intravesical delivery system of gemcitabine HCl (Gem-HCl) to provide a sustained-release profile, to prolong residence time, and to enhance its efficiency in the treatment of bladder cancer.

MATERIALS AND METHODS

For this purpose, bioadhesive microspheres were successfully prepared with average particle size, encapsulation efficiency, and loading capacity of 98.4 µm, 82.657%±5.817%, and 12.501±0.881 mg, respectively. For intravesical administration, bioadhesive microspheres were dispersed in mucoadhesive chitosan or in situ poloxamer gels and characterized in terms of gelation temperature, viscosity, mechanical, syringeability, and bioadhesive and rheological properties. The cytotoxic effects of Gem-HCl solution, Gem-HCl microspheres, and Gem-HCl microsphere-loaded gel formulations were evaluated in two different bladder cancer cell lines: T24 (ATCC HTB4TM) and RT4 (ATCC HTB2TM).

RESULTS

According to cell-culture studies, Gem-HCl microsphere-loaded poloxamer gel was more cytotoxic than Gem-HCl microsphere-loaded chitosan gel. Antitumor efficacy of newly developed formulations were investigated by in vivo studies using bladder-tumor-induced rats.

CONCLUSION

According to in vivo studies, Gem-HCl microsphere-loaded poloxamer gel was found to be an effective and promising alternative for current intravesical delivery-system therapies.

Design and evaluation of an intravesical delivery system for superficial bladder cancer: preparation of gemcitabine HCl-loaded chitosan-thioglycolic acid nanoparticles and comparison of chitosan/poloxamer gels as carriers

This study aimed to develop an intravesical delivery system of gemcitabine HCl for superficial bladder cancer in order to provide a controlled release profile, to prolong the residence time, and to avoid drug elimination via urination. For this aim, bioadhesive nanoparticles were prepared with thiolated chitosan (chitosan–thioglycolic acid conjugate) and were dispersed in bioadhesive chitosan gel or in an in situ gelling poloxamer formulation in order to improve intravesical residence time. In addition, nanoparticle-loaded gels were diluted with artificial urine to mimic in vivo conditions in the bladder and were characterized regarding changes in gel structure. The obtained results showed that chitosanthioglycolic acid nanoparticles with a mean diameter of 174.5±3.762 nm and zeta potential of 32.100±0.575 mV were successfully developed via ionotropic gelation and that the encapsulation efficiency of gemcitabine HCl was nearly 20%. In vitro/ex vivo characterization studies demonstrated that both nanoparticles and nanoparticle-loaded chitosan and poloxamer gels might be alternative carriers for intravesical administration of gemcitabine HCl, prolonging its residence time in the bladder and hence improving treatment efficacy. However, when the gel formulations were diluted with artificial urine, poloxamer gels lost their in situ gelling properties at body temperature, which is in conflict with the aimed formulation property. Therefore, 2% chitosan gel formulation was found to be a more promising carrier system for intravesical administration of nanoparticles.

Preclinical analyses of intravesical chemotherapy for prevention of bladder cancer progression

There is a critical need to identify treatment options for patients at high risk for developing muscle invasive bladder cancer that avoid surgical removal of the bladder (cystectomy). In the current study, we have performed preclinical studies to investigate the efficacy of intravesical delivery of chemotherapy for preventing progression of bladder cancer. We evaluated three chemotherapy agents, namely cisplatin, gemcitabine, and docetaxel, which are currently in use clinically for systemic treatment of muscle invasive bladder cancer and/or have been evaluated for intravesical therapy. These preclinical studies were done using a genetically-engineered mouse (GEM) model that progresses from carcinoma in situ (CIS) to invasive, metastatic bladder cancer. We performed intravesical treatment in this GEM model using cisplatin, gemcitabine, and/or docetaxel, alone or by combining two agents, and evaluated whether such treatments inhibited progression to invasive, metastatic bladder cancer. Of the three single agents tested, gemcitabine was most effective for preventing progression to invasive disease, as assessed by several relevant endpoints. However, the combinations of two agents, and particularly those including gemcitabine, were more effective for reducing both tumor and metastatic burden. Our findings suggest combination intravesical chemotherapy may provide a viable bladder-sparing treatment alternative for patients at high risk for developing invasive bladder cancer, which can be evaluated in appropriate clinical trials.

Superficial bladder cancer: part 2. Management

In the second section of a two-part article, the recent literature is reviewed and the management of nonmuscle-invasive transitional cell carcinoma of the bladder is discussed. Particular attention is given to the indications and timing of intravesical chemotherapy and immunotherapy and the differences in efficacy and side-effect profiles of the available agents. The indications and role of second-look transurethral resection are reviewed. Additionally, the role of bacillus Calmette-Guerin in the management of this disease in terms of definitive treatment and maintenance therapy is discussed. We also offer a review of the literature regarding therapies for bacillus Calmette-Guerin-refractory nonmuscle-invasive transitional cell carcinoma of the bladder and their current place in practice.

Update on the management of non-muscle invasive bladder cancer

Non-muscle invasive bladder cancer (NMIBC) is a heterogeneous population of tumours accounting for 80% of bladder cancers. Over the years, the management of this disease has been changing with improvements in results and outcomes. In this review, we focus on the latest updates on the management of NMIBC.

Intravesical Bacillus Calmette-Guérin versus epirubicin for Ta and T1 bladder cancer

BACKGROUND

Bladder cancer accounts for approximately 4.4% of adult malignancies, and approximately 80% of bladder cancer presents initially as transitional cell carcinoma that is confined to the urothelium (stage Ta) or lamina propria (stage T1). Intravesical administration of Bacillus Calmette-Guérin (BCG) and epirubicin (EPI) has been proven to reduce tumour recurrence and prevent or delay progression to muscle invasion and metastases. However, comparison of the effectiveness and safety of intravesical BCG and EPI in bladder cancer has yet to be explored.

OBJECTIVES

To compare the effectiveness and safety of BCG with EPI in the treatment of Ta and T1 bladder cancer.

SEARCH STRATEGY

A comprehensive search of MEDLINE (1966 to April 2010), EMBASE (1980 to April 2010), Health Services Technology, Administration, and Research (HealthSTAR), the Cochrane Central Register of Controlled Trials (CENTRAL), CancerLit, and Database of Abstracts of Reviews of Effectiveness (DARE), was performed, and handsearching of relevant journals was undertaken.

SELECTION CRITERIA

All randomised or quasi-randomised trials (in which allocation was obtained by alternation - e.g., alternate medical records, date of birth, or other predictable methods) in patients with Ta or T1 bladder cancer that compared intravesical BCG with EPI were included. No language restrictions were applied.

DATA COLLECTION AND ANALYSIS

Trial eligibility, methodological quality and data extraction were assessed independently by two reviewers. We compared dichotomous outcomes (frequency of tumour recurrence, progressive disease by stage, mortality, distant metastases, local and systemic adverse effects, treatment delayed or stopped due to adverse effects) using risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Five trials of 1111 participants were included in this review. For BCG, 549 patients were treated, and 562 with EPI. Of the evaluated patients, 35.5% (195/549) in the BCG group and 51.4% (289/562) in the EPI group had tumour recurrence (P < 0.05). For disease progression (BCG, 44/549; EPI, 58/562) and distant metastases (BCG, 23/487; EPI, 31/495), there were no significant differences (P = 0.19 and P = 0.29, respectively). Only two trials, including 769 patients, had sufficient data for us to analyze disease-specific (BCG, 22/383; EPI, 26/386) and overall mortality (BCG, 125/383; EPI, 147/386). Neither comparison was significant (P = 0.93 and P = 0.12, respectively). In four studies reporting toxicity, BCG was associated with significantly more drug-induced cystitis [BCG, 54.1% (232/429); EPI, 31.7% (140/441)] and haematuria [BCG, 30.8% (132/429); EPI, 16.1% (71/440)]. Similarly, in three studies reporting systemic toxicity, BCG had significantly higher toxicity than the EPI (34.8% (134/385) versus 1.3% (5/393), respectively). In a meta-analysis comparing 'treatment delayed or stopped' (BCG, 40/431; EPI, 33/441), there was no significant difference between BCG and EPI treatments (P = 0.82).

AUTHORS' CONCLUSIONS

The data from the present meta-analysis indicate that intravesical BCG treatment is more efficacious than EPI in reducing tumour recurrence for Ta and T1 bladder cancer. However, BCG appears to be associated with a higher incidence of adverse effects, such as drug-induced cystitis, haematuria and systemic toxicity, than EPI. The overall quality of the evidence is rather low. Well-designed, high quality randomised controlled trials with good allocation concealment are required.

[Intravesical therapy in non-muscle-invasive bladder cancer: indications and practical considerations]

Intravesical treatment with various agents is an accepted standard for treating patients with non-muscle-invasive bladder cancer; all guidelines recommend its use. Depending on the agent and the instillation schedule, a reduction in recurrence and a decrease in the progression rate can be achieved.However, many of the recommendations in the various guidelines are currently under debate. Early instillation with a chemotherapeutic agent is probably overtreatment in patients requiring further induction or maintenance therapy because it adds no further benefit. The economic aspects of early instillations are also being discussed. Recent studies question the ability of bacillus Calmette-Guérin (BCG) instillations to reduce the progression of non-muscle-invasive bladder cancer. Furthermore, the superiority of maintenance therapies compared with induction schedules is under debate.There is a great body of evidence that the effectiveness of intravesical chemotherapy can be increased by simple measures. Reduction of BCG side effects without compromising the oncological outcome is possible.

New therapies for non-muscle-invasive bladder cancer

The treatment of non-muscle-invasive bladder cancer (NMIBC) remains a challenge owing to its increased tendency to recur and the possibility of progression to potentially dangerous muscle-invasive disease. Treatment outcomes by current therapeutic modalities are still not optimal. In recent years, there have been a number of substantive advances in the therapeutic options for the management of NMIBC. New chemotherapeutic drugs have been introduced, along with efforts made to improve the efficacy of existing agents and enhance delivery of agents to the bladder. There is also a growing trend toward combination of agents and multimodal therapy. Also of considerable interest are the investigation of newer approaches such as gene therapy, chemoenhancement and newer forms of immunotherapy. Here, we review the recent pre-clinical and clinical developments in the treatment of NMIBC, described in the broad categories of immunotherapy, chemotherapeutic agents, improved or device-assisted agent delivery and gene therapy.

Second-Line Intravesical Gemcitabine in High Risk Superficial Bladder Cancer: Our Experience

Purpose

Intravesical instillation of Gemcitabine may represent a useful second-line chemotherapy in case of non-muscle-invasive bladder cancer. Herein, we reported our experience with intravesical Gemcitabine in a group of patients affected by high-grade transitional cell carcinoma (TCC) of the bladder.

Materials and Methods

We retrospectively analyzed a total of 17 patients (15 males and 2 females), affected by high-risk superficial bladder cancer, who were refractory, intolerant or not eligible to intravesical BCG immunotherapy. Each patient received 2000 mg of Gemcitabine diluted in 100 mL of 0.9% saline solution, administered twice a week for 6 weeks. At start, TCC stage and grade were: CIS in 10 patients, TaG3 in 5 and T1G3 in the remaining 2 cases. Those with no macroscopic lesion and negative cytology and histology were considered as complete responders; those with only positive cytology as partial responders, and those with positive biopsy or evidence of macroscopic lesions as non-responders.

Results

Patients’ mean age was 71.5 yrs (± 7.3 yrs standard deviation). Overall, median follow-up was 12 months [interquartile range (IQR) 9–15 months]. A complete remission was achieved in 10 cases (58.8%), a partial response in 2 (11.8%), while 5 patients (29.4%) were considered as non-responders. Tumor stage and/or grade progression was observed in 26.7% of the cases. Overall, the 6-month recurrence-free survival was 33.3%. Drug toxicity was relatively low: 2 patients developed a grade II dysuria (NCI-CTC criteria); fever >38° was observed in 1 case.

Conclusions

Although our experience and follow-up are still rather limited to formulate any conclusive assessment, our study seems to confirm that Gemcitabine could be used as a safe and efficient intravesical chemotherapy agent even in high grade TCCs, representing a promising second-line option in those cases who failed, were intolerant or not eligible to BCG therapy. (Urologia 2009; 76: 178–84)

Perioperative instillation therapy in superficial bladder cancer: is it effective regarding outcome and costs?

PURPOSE OF REVIEW

This article reviews the current knowledge concerning immediate intravesical instillation therapy in nonmuscle-invasive bladder cancer after transurethral resection of the bladder tumour, with emphasis on the literature of the last few years.

RECENT FINDINGS

A review was conducted on the recent literature available by PubMed database on the subject of immediate bladder chemotherapy after transurethral resection of the bladder tumour and its recent developments.

SUMMARY

A single immediate bladder instillation with chemotherapy will give 39% reduction of recurrence. Numbers needed to treat to prevent one recurrence are estimated at 8.5. In intermediate and high-risk bladder cancer, the immediate postoperative instillation does not give sufficient reduction in recurrence rate to leave out subsequent bladder instillations. The significant reduction of recurrences, the mild side-effects of the treatment and the clear cost-effectiveness make one immediate instillation a valuable addition to transurethral resection of the bladder tumour in the treatment of nonmuscle-invasive bladder cancer. Points of controversy are the true numbers needed to treat to prevent a recurrence and the type of recurrences that will be prevented. No new types of instillation are added recently to the ones available, but promising types are under investigation of which pharmacokinetic studies have shown acceptable rates of side-effects.

The novel use of intravesical docetaxel for the treatment of non-muscle invasive bladder cancer refractory to BCG therapy: a single institution experience

OBJECTIVES

Since the success of our Phase I trial of intravesical docetaxel for treatment-refractory non-muscle invasive bladder cancer (NMIBC), we have found this agent to be a favorable alternative for BCG-refractory patients unable or unwilling to undergo cystectomy. This study analyzes the safety and efficacy of intravesical docetaxel in a larger patient population with extended follow-up.

METHODS

A retrospective analysis of all patients who received salvage intravesical docetaxel at our institution was conducted, including 18 patients treated during the Phase I trial and 15 patients treated after the trial's completion. Toxicity, efficacy and recurrence-free survival were analyzed.

RESULTS

Thirty-three patients with refractory NMIBC received salvage intravesical docetaxel therapy between 2003 and 2008 at a single institution. Twenty of thirty-three (61%) patients had a complete response (CR) after six weekly induction treatments. Ten patients with CRs were given maintenance docetaxel therapy, and one patient received maintenance BCG and interferon. With a median follow-up of 29 months, 1 and 2-year recurrence-free survival rates were and 45 and 32%, respectively. Twelve of thirty-three patients (36%) had Grade 1 or 2 local toxicities. No patients experienced Grade 3 or 4 toxicities.

CONCLUSIONS

Docetaxel is a promising intravesical agent with minimal toxicity and significant efficacy and durability for the management of BCG-refractory NMIBC.

Intravesical Pharmacotherapy for Non–Muscle-Invasive Bladder Cancer: A Critical Analysis of Currently Available Drugs, Treatment Schedules, and Long-Term Results

OBJECTIVES

Review adjuvant intravesical pharmacotherapy for non-muscle-invasive bladder cancer (NMIBC), emphasising treatment schedules and long-term results.

METHODS

Search of published literature on conventional treatment of NMIBC, emerging drugs, and device-assisted therapies.

RESULTS

In low-risk NMIBC patients an immediate instillation with chemotherapy is sufficient. For patients with intermediate- or high-risk tumours, additional adjuvant instillations are needed. For intermediate-risk patients chemotherapeutic instillations, usually with mitomycin C or epirubicin, are safe and effective in reducing the risk of recurrence in the short term, but efficacy is only marginal in the long term. Newer drugs have promising results, but long term follow-up is limited or lacking. In these patients bacillus Calmette-Guérin (BCG) does not seem to be more effective, only more toxic. In high-risk NMIBC, or patients in whom chemotherapy fails, BCG is the best choice with lower rates of recurrence and progression. For BCG failures cystectomy is therapy of choice, although the combination of BCG and interferon-alpha can be considered, just as device-assisted therapies such as thermochemotherapy and electromotive drug administration.

CONCLUSIONS

Risk-adapted first-line adjuvant therapy for NMIBC after TURBT is well established but has its limitations because recurrences are still numerous. Some new drugs and second-line therapies are promising, but efficacy should be confirmed.

Current strategies for first and second line intravesical therapy for nonmuscle invasive bladder cancer

PURPOSE OF REVIEW

Nonmuscle invasive bladder cancer is a common malignancy, usually treated by transurethral resection and adjuvant intravesical instillations of chemotherapy or immunotherapy. Appropriate adjuvant treatment can be selected based on several prognostic factors that determine risk for recurrence or progression. We discuss options for first-line and second-line adjuvant therapy for nonmuscle invasive bladder cancer.

RECENT FINDINGS

Mitomycin-C and epirubicin are the mostly used adjuvant chemotherapeutic drugs for tumours of low and intermediate risk. Bacillus Calmette-Guérin remains first-choice therapy in high-risk nonmuscle invasive bladder cancer. Gemcitabine and apaziquone are especially promising for treatment of intermediate risk nonmuscle invasive bladder cancer but require further study. Device-assisted therapies, such as thermochemotherapy and electromotive drug administration, have yielded good results in high-risk nonmuscle invasive bladder cancer and could be considered second-line therapy in this setting.

SUMMARY

Primary problems in nonmuscle invasive bladder cancer are its tendency to recur and its elusiveness (especially high-risk nonmuscle invasive bladder cancer) of progression to muscle invasive disease. First-line adjuvant therapies are well established but suboptimal. Some second-line therapies are promising but should be used cautiously, because in some patients the best option is not always the conservative one.

Intravesical gemcitabine: an update of clinical results

PURPOSE OF REVIEW

Nonmuscle-invasive bladder cancer is a common malignancy, standardly treated by transurethral resection and adjuvant intravesical instillations of chemotherapy or immunotherapy. Adjuvant instillations are needed to reduce recurrence and/or progression. With currently existing adjuvant treatments, however, recurrences still occur, progression is hardly influenced and these treatments induce local or systemic side effects. In search for efficacy improvement and side effect reduction, we reviewed the promising properties of the relatively new intravesical drug, gemcitabine.

RECENT FINDINGS

The safety of gemcitabine is tested in different instillation schemes, drug concentrations and administered volumes. Its safety profile is excellent, with good tolerability and minimal toxicity up to 2000 mg/50 ml for 2-h instillations. In comparison with other drugs, the ablative efficacy of gemcitabine is good. The first studies on prophylactic efficacy in intermediate-risk, high-risk and bacillus Calmette-Guerin-refractory patients are promising but limited by the small number of patients studied.

SUMMARY

The available literature underlines the promising properties of gemcitabine for the intravesical use against nonmuscle-invasive bladder cancer. Exploring phase-II and comparative randomized phase-III studies should provide additional information on gemcitabine and its benefit to clinical practice.

Improving Efficacy of Intravesical Chemotherapy

OBJECTIVE

This paper reviews the most relevant findings published recently on intravesical chemotherapy for superficial bladder tumours and provides recommendations based on documented research.

METHODS

The evidence was categorised according to the North of England Evidence Based Guideline Development Project. Levels of evidence were based on the source of the information, meta-analyses, systematic reviews, well-designed randomised or nonrandomised controlled clinical trials, and uncontrolled studies or consensus. Three levels of recommendations were assigned to the evidence obtained.

RESULTS

Despite intravesical chemotherapy being used prophylactically after endoscopic resection of superficial bladder tumours, the recurrence rate is still 36-44%. Researchers have focused on improving the effectiveness of intravesical chemotherapy, each adopting a different strategy. Some have aimed to identify the optimum timing for instillations and others to improve the pharmacokinetics of agents by avoiding their dilution, increasing their stability, or improving the absorption of the drug by bladder mucosa. Some researchers are looking into new, single chemotherapeutic agents or combinations for intravesical use and others into avoiding chemoresistance with resistance-reverting agents (modulating agents) or by using in vitro chemosensitivity tests to identify the most sensitive drug.

CONCLUSION

Progress has been made in optimising intravesical chemotherapy for timing of instillations and pharmacokinetic interventions. Simple and inexpensive approaches may have a widespread, practical acceptance by urologists, but it is more difficult to extend new techniques requiring more complex and sometimes expensive instrumentation to the urologic community. Further research into finding more effective cytotoxic drugs, combinations, or modulating agents should be encouraged.

Actual experience and future development of gemcitabine in superficial bladder cancer

Gemcitabine has a molecular weight of 299 D, lower than that of commonly-used intravesical chemotherapeutic agents such as mitomycin C (389 D) and doxorubicin (589 D). This may enable gemcitabine to penetrate the bladder mucosa with beneficial effects in the treatment of early invasive bladder cancer (T1 disease). At the same time the molecular weight is high enough to prevent significant systemic absorption in an intact bladder. Based on the results of phase I studies, it appears that the 2000 mg dose of gemcitabine in 50/100 ml normal saline when administered intravesically for up to 2 h once a week for 6 weeks has unremarkable systemic and local side effects and therefore should be considered the most convenient schedule. The currently available phase II studies have assessed the activity of intravesical gemcitabine on a marker lesion in intermediate risk superficial bladder cancers (SBC), showing complete responses in up to 56% of cases. Few attempts have been made to test the activity of intravesical gemcitabine in high risk SBC achieving unexpected complete responses in BCG refractory CIS. Gemcitabine seems to have fulfilled the requirements to be a promising new candidate for standard intravesical therapy in SBC so far. Further phase II trials exploring the activity of gemcitabine on highly-recurrent intermediate risk or high risk SBC would provide additional information to foresee its efficacy in clinical practice and thus constitute the framework for large comparative phase III trials.

Antitumor activity of the antimicrobial peptide magainin II against bladder cancer cell lines

OBJECTIVE

Magainin II belongs to a family of antimicrobial peptides and has been shown to exhibit antibiotic activity in a wide range of organisms. Recent studies have also reported a significant antitumor effect of magainin II against various cancer cell lines and tumor mice models. In this study, we evaluated the cytotoxic and antiproliferative potency of magainin II in bladder tumor cells and normal fibroblasts.

METHODS

The antiproliferative and cytotoxic effect of magainin II was quantified by colorimetric WST-1-, bromodeoxyuridine (BrdU)-, and lactic dehydrogenase (LDH) assays in three bladder cancer cell lines (RT4, 647V, and 486P) and in the murine fibroblast cell line 3T3 as well as in a primary culture from human fibroblasts. The median inhibitory concentration (IC50) values were determined for each assay, representing the concentration at which cell viability was reduced by 50%. Scanning electron microscopy (SEM) was used to visualize the morphologic effects of magainin II on bladder tumor cells and fibroblasts.

RESULTS

Magainin II inhibited cell proliferation of bladder cancer cells in a dose-dependent manner. The average IC50 of magainin II against all bladder cancer cell lines was 198.1 microM (range, 52.4-484.03 microM) for the WST-1 assay and 75.2 microM (range, 31.0-135.3 microM) for the BrdU assay. The normal murine and human fibroblast cell lines were not affected by magainin II and their IC50 could not be determined at the concentrations of magainin II tested. LDH release was increased in all bladder tumor cell lines in the presence of magainin II, whereas normal fibroblasts showed no cell lysis. SEM demonstrated lethal membrane perforation by peptide pore formation in bladder cancer cells, but not in fibroblasts.

CONCLUSION

Magainin II peptide exerts cytotoxic and antiproliferative efficacy by pore formation in bladder cancer cells but has no effect on normal murine or human fibroblasts. Magainin II may offer a novel therapeutic strategy in the treatment of bladder cancer with potentially low cytotoxic effects on normal cells.

Intravesical gemcitabine therapy for superficial transitional cell carcinoma: Results of a Phase II prospective multicenter study

OBJECTIVES

To determine the tolerability and efficacy after 1 year of weekly intravesical gemcitabine therapy in patients with intermediate-risk and high-risk superficial transitional cell carcinoma.

METHODS

A total of 116 patients with intermediate-risk and high-risk bladder cancer who had undergone transurethral resection were treated with one cycle (once a week for 6 weeks) of gemcitabine 2000 mg. Local and systemic tolerability and efficacy were evaluated.

RESULTS

In terms of the tolerability of gemcitabine, 14 patients (12.0%) reported urgency, 6 (5.1%) dizziness and slight fever (less than 38 degrees C), 1 (0.8%) severe abdominal pain, with ulcerative lesions of the bladder mucosa at cystoscopy, and 1 (0.8%) parosmia. The remaining 94 patients (81.3%) did not report any local side effects during the treatment period. In terms of efficacy, recurrence developed in 29 patients (25.4%) a mean of 7 months after transurethral resection; 85 patients (74.6%) were disease free after 12 months. The univariate analysis showed a greater level of efficacy in patients with a first occurrence (P = 0.0408), patients who had had no previous treatment (P = 0.0368), and patients with Stage pTa superficial transitional cell carcinoma (P = 0.0018). The multivariate analysis did not reveal any significant data. No significant differences were found between the intermediate-risk and high-risk patients in tolerability or efficacy. No recurrence developed in 18 (75%) of 24 intermediate-risk bacille Calmette-Guérin-refractory or 7 (43.7%) of 16 high-risk bacille Calmette-Guérin-refractory patients.

CONCLUSIONS

The results of our study have confirmed the good tolerability and 1 year efficacy of intravesical gemcitabine. The treatment schedule proposed resulted in high patient compliance, and the results can be compared with the results of studies using other intravesical treatments.

New agents in intravesical chemotherapy of superficial bladder cancer

Although intravesical chemotherapy has been used in the management of superficial bladder cancer for some decades, until recently there has been little or no progress in the search for new agents. However, in the past few years there have been developments of investigational drugs that may play a future role in this indication. This review highlights the mode of action, indications, dose and administration, efficacy, safety and significance of new chemotherapeutic agents such as intravesical valrubicin, gemcitabine, suramin, gamma-linolenic acid, eflornithine (DFMO), tipifarnib (R115777), fenritinide and celecoxib. Although the initial results achieved with these agents in clinical development seem encouraging, long-term data on the prevention of recurrence, disease progression and survival have yet to be obtained.

Randomized Phase II marker lesion study evaluating effect of scheduling on response to intravesical gemcitabine in recurrent Stage Ta urothelial cell carcinoma of the bladder

OBJECTIVES

To evaluate the response rate for intravesical gemcitabine given in three different schedules to patients with recurrent multiple carcinoma of the urinary bladder Stage Ta, grade 1-2, in whom all but one marker lesion was removed. Furthermore, we sought to define the safety profile.

METHODS

This was a multicenter, open-label, randomized, Phase II study in which gemcitabine 2000 mg in 100 mL of unbuffered saline was instilled as a single dose (n = 11), two doses per week for 3 weeks (n = 11), or once weekly for 6 weeks (n = 10). Efficacy was evaluated using cystoscopy after 9 weeks. Toxicity was evaluated by assessing the liver, kidney, bone marrow, and coagulation function at defined intervals and by questionnaire.

RESULTS

A total of 32 patients were included, 2 of whom were subsequently excluded because of protocol violations. The overall complete remission rate was 31%. The respective subgroup response rate was 10% in the single-dose group, 44% in the once-weekly group, and 40% in the twice-weekly group. The most common side effect was nausea. One patient withdrew because of nausea and fever, and an additional 2 patients had reversible hematologic toxicity (mild thrombocytopenia causing delayed instillation and mild anemia). The side effects were generally in the multiple-dose groups, with an overrepresentation in women. Ten patients were unable to retain the drug intravesically for the full hour.

CONCLUSIONS

The results of our study have shown that gemcitabine has a tumor ablative effect when given intravesically for bladder cancer. A single dose seemed ineffective, and the multiple dosing regimens seemed effective. The side effects were generally mild.

Intravesical Gemcitabine for Superficial Bladder Carcinoma

The increasing complexity of cancer chemotherapy makes it mandatory that pharmacists be familiar with these highly toxic agents. This column focuses on the commercially available and investigational agents used to treat malignant diseases and reviews issues related to the preparation, dispensing, and administration of cancer chemotherapy.

Second-line intravesical therapy versus cystectomy for bacille Calmette-Gu??rin (BCG) failures

PURPOSE OF REVIEW

To give an update on the new modalities in treating patients with superficial bladder cancer who have failed bacille Calmette-Guérin.

RECENT FINDINGS

The addition of interferon to bacille Calmette-Guérin has proven to be an effective combination therapy for bacille Calmette-Guérin failures. Electromotive intravesical mitomycin C as well as local microwave hyperthermia have been shown to improve drug delivery and increase response rates. Intravesical gemcitabine has shown some promising results in phase I studies and is being investigated in phase II trials. Photodynamic therapy is proposed as a second-line therapy for bacille Calmette-Guérin failures.

SUMMARY

New treatment modalities are being introduced and existing ones improved to treat bacille Calmette-Guérin-refractory superficial bladder cancer. These agents need to be studied in large randomized trials. Until these agents prove to decrease recurrence rates and delay progression of high-risk superficial bladder cancer, cystectomy remains the standard of care for the patient who is a good surgical candidate and willing to undergo such major surgery.

Phase II Study to Investigate the Ablative Efficacy of Intravesical Administration of Gemcitabine in Intermediate-Risk Superficial Bladder Cancer (SBC)

OBJECTIVE

Phase I studies have so far demonstrated that intravesical Gemcitabine up to a 40 mg/ml concentration is well tolerated and has a substantial ablative activity on high-risk BCG refractory SBC. New treatment options are needed for intermediate-risk SBC recurring after conventional intravesical treatments. The purpose of the present study was to investigate the ablative efficacy of intravesical Gemcitabine on intermediate-risk SBC.

METHODS

The study was designed as a two-stage phase II trial, with a sample size of 39 patients. The efficacy of intravesical Gemcitabine at a concentration of 40 mg/ml (2000 mg in 50 ml saline solution) administered weekly for 6 weeks was assessed on a single marker tumour left in the bladder after a complete TUR of all other lesions. Patients underwent TUR or biopsy at the site of the marker lesion 2 weeks after completion of the treatment.

RESULTS

Complete response was observed in 22 out of 39 patients (56%). No progression was observed among the 17 non-responders. Neither systemic nor local side effects generally exceeded grade I toxicity.

CONCLUSION

The ablative effect of Gemcitabine produced a higher number of responses than the minimum required by the protocol to indicate a significant probability of drug efficacy. It is worth testing the drug in phase III trials to assess for durability of response.