Continuous infusion gallium nitrate for patients with advanced refractory urothelial tract tumors

Challenges and Chances in the Preclinical to Clinical Translation of Anticancer Metallodrugs

Despite being “sentenced to death” for quite some time, anticancer platinum compounds are still the most frequently prescribed cancer therapies in the oncological routine and recent exciting news from late-stage clinical studies on combinations of metallodrugs with immunotherapies suggest that this situation will not change soon. It is perhaps surprising that relatively simple molecules like cisplatin, discovered over 50 years ago, are still widely used clinically, while none of the highly sophisticated metal compounds developed over the last decade, including complexes with targeting ligands and multifunctional (nano)formulations, have managed to obtain clinical approval. In this book chapter, we summarize the current status of ongoing clinical trials for anticancer metal compounds and discuss the reasons for previous failures, as well as new opportunities for the clinical translation of metal complexes.

Clinical pharmacology and clinical trials of ribonucleotide reductase inhibitors: is it a viable cancer therapy?

PURPOSE

Ribonucleotide reductase (RR) enzymes (RR1 and RR2) play an important role in the reduction of ribonucleotides to deoxyribonucleotides which is involved in DNA replication and repair. Augmented RR activity has been ascribed to uncontrolled cell growth and tumorigenic transformation.

METHODS

This review mainly focuses on several biological and chemical RR inhibitors (e.g., siRNA, GTI-2040, GTI-2501, triapine, gemcitabine, and clofarabine) that have been evaluated in clinical trials with promising anticancer activity from 1960's till 2016. A summary on whether their monotherapy or combination is still effective for further use is discussed.

RESULTS

Among the RR2 inhibitors evaluated, GTI-2040, siRNA, gallium nitrate and didox were more efficacious as a monotherapy, whereas triapine was found to be more efficacious as combination agent. Hydroxyurea is currently used more in combination therapy, even though it is efficacious as a monotherapy. Gallium nitrate showed mixed results in combination therapy, while the combination activity of didox is yet to be evaluated. RR1 inhibitors that have long been used in chemotherapy such as gemcitabine, cladribine, fludarabine and clofarabine are currently used mostly as a combination therapy, but are equally efficacious as a monotherapy, except tezacitabine which did not progress beyond phase I trials.

CONCLUSIONS

Based on the results of clinical trials, we conclude that RR inhibitors are viable treatment options, either as a monotherapy or as a combination in cancer chemotherapy. With the recent advances made in cancer biology, further development of RR inhibitors with improved efficacy and reduced toxicity is possible for treatment of variety of cancers.

An in vitro enzymatic assay to measure transcription inhibition by gallium(III) and H3 5,10,15-tris(pentafluorophenyl)corroles

Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UV-Vis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.

Iron-targeting antitumor activity of gallium compounds and novel insights into triapine(®)-metal complexes

SIGNIFICANCE

Despite advances made in the treatment of cancer, a significant number of patients succumb to this disease every year. Hence, there is a great need to develop new anticancer agents.

RECENT ADVANCES

Emerging data show that malignant cells have a greater requirement for iron than normal cells do and that proteins involved in iron import, export, and storage may be altered in cancer cells. Therefore, strategies to perturb these iron-dependent steps in malignant cells hold promise for the treatment of cancer. Recent studies show that gallium compounds and metal-thiosemicarbazone complexes inhibit tumor cell growth by targeting iron homeostasis, including iron-dependent ribonucleotide reductase. Chemical similarities of gallium(III) with iron(III) enable the former to mimic the latter and interpose itself in critical iron-dependent steps in cellular proliferation. Newer gallium compounds have emerged with additional mechanisms of action. In clinical trials, the first-generation-compound gallium nitrate has exhibited activity against bladder cancer and non-Hodgkin's lymphoma, while the thiosemicarbazone Triapine(®) has demonstrated activity against other tumors.

CRITICAL ISSUES

Novel gallium compounds with greater cytotoxicity and a broader spectrum of antineoplastic activity than gallium nitrate should continue to be developed.

FUTURE DIRECTIONS

The antineoplastic activity and toxicity of the existing novel gallium compounds and thiosemicarbazone-metal complexes should be tested in animal tumor models and advanced to Phase I and II clinical trials. Future research should identify biologic markers that predict tumor sensitivity to gallium compounds. This will help direct gallium-based therapy to cancer patients who are most likely to benefit from it.

Differential cytostatic and cytotoxic action of Metallocorroles against human cancer cells: potential platforms for anticancer drug development

A gallium(III)-substituted amphiphilic corrole noncovalently associated with a targeting protein was previously found by us to confer promising cytotoxic and antitumor activities against a breast cancer cell line and a mouse xenograft breast cancer model. To further explore potential anticancer applications, the cytostatic and cytotoxic properties of six nontargeted metallocorroles were evaluated against seven human cancer cell lines. Results indicated that toxicity toward human cancer cells depended on the metal ion as well as corrole functional group substitution. Ga(III)-substituted metallocorrole 1-Ga inhibited proliferation of breast (MDA-MB-231), melanoma (SK-MEL-28), and ovarian (OVCAR-3) cancer cells primarily by arrest of DNA replication, whereas 2-Mn displayed both cytostatic and cytotoxic properties. Confocal microscopy revealed extensive uptake of 1-Ga into the cytoplasm of melanoma and ovarian cancer cells, while prostate cancer cells (DU-145) displayed extensive nuclear localization. The localization of 1-Ga to the nucleus in DU-145 cells was exploited to achieve a 3-fold enhancement in the IC(50) of doxorubicin upon coadministration. Time-course studies showed that over 90% of melanoma cells incubated with 30 μM 1-Ga internalized metallocorrole after 15 min. Cellular uptake of 1-Ga and 1-Al was fastest and most efficient in melanoma, followed by prostate and ovarian cancer cells. Cell cycle analyses revealed that bis-sulfonated corroles containing Al(III), Ga(III), and Mn(III) induced late M phase arrest in several different cancer cell lines, a feature that could be developed for potential therapeutic benefit.

Advanced bladder cancer: new agents and new approaches. A review

OBJECTIVE

The aim of the present paper is to review findings from the most relevant studies and evaluate the potential of new drugs in treatment of metastatic urothelial cancer.

METHODS

Studies were identified by searching MEDLINE and Pubmed databases up to 2009 using both medical subject heading (Mesh) and a free text strategy with the name of known individual chemotherapeutic drug and the following key words: 'muscle-invasive bladder cancer', 'urothelial/transitional carcinoma', 'chemotherapeutics drugs and agents'. At the end of our research in literature we selected 63 articles and we have considered only studies in which almost 30 patients were enrolled.

RESULTS

Radical cystectomy with pelvic lymph node dissection is the gold standard of treatment for clinically localized muscle-invasive bladder cancer. While more extensive lymph node dissection may have both prognostic and therapeutic significance, effective systemic therapies that eliminate micrometastases may improve outcome. Perioperative chemotherapy can be administered before (neoadjuvant) or after (adjuvant) cystectomy to eradicate subclinical disease and to improve survival.

CONCLUSION

The challenge remains as to how to integrate all of the relevant knowledge and data in a systematic manner so that researchers can gain the knowledge needed to devise the best therapeutic and diagnostic strategies. Future improvements in the treatment of advanced bladder cancer will rely not only on the optimization of currently available cytotoxic agents but also on the biologic profile of individual patient tumors and the appropriate therapies that target molecular aberrations unique to this malignancy.

Medical applications and toxicities of gallium compounds

Over the past two to three decades, gallium compounds have gained importance in the fields of medicine and electronics. In clinical medicine, radioactive gallium and stable gallium nitrate are used as diagnostic and therapeutic agents in cancer and disorders of calcium and bone metabolism. In addition, gallium compounds have displayed anti-inflammatory and immunosuppressive activity in animal models of human disease while more recent studies have shown that gallium compounds may function as antimicrobial agents against certain pathogens. In a totally different realm, the chemical properties of gallium arsenide have led to its use in the semiconductor industry. Gallium compounds, whether used medically or in the electronics field, have toxicities. Patients receiving gallium nitrate for the treatment of various diseases may benefit from such therapy, but knowledge of the therapeutic index of this drug is necessary to avoid clinical toxicities. Animals exposed to gallium arsenide display toxicities in certain organ systems suggesting that environmental risks may exist for individuals exposed to this compound in the workplace. Although the arsenic moiety of gallium arsenide appears to be mainly responsible for its pulmonary toxicity, gallium may contribute to some of the detrimental effects in other organs. The use of older and newer gallium compounds in clinical medicine may be advanced by a better understanding of their mechanisms of action, drug resistance, pharmacology, and side-effects. This review will discuss the medical applications of gallium and its mechanisms of action, the newer gallium compounds and future directions for development, and the toxicities of gallium compounds in current use.

New agents for treatment of advanced transitional cell carcinoma

The prognosis for any patient with progressive or recurrent invasive transitional cell carcinoma remains poor. In this context, the focus of clinical research in these invasive cancers concentrates on identifying systemic treatment options and new agents in order to improve survival of patients. Cisplatin-based chemotherapy is standard treatment of patients with metastatic urothelial cancer; however, despite regimens as the cisplatin-gemcitabine combination, the overall response rates vary between 40% and 65%, with complete response in 15%-25% with survivals up to 16 months. This survival is frequently achieved with severe and life-threatening side effects. None the less, almost all responding patients relapse within the first year; therefore, the need for development of new and tolerable agents is urgent. This review highlights some new active chemotherapeutic as new platinum compounds (oxaliplatin, lobaplatin), gallium nitrate, ifosfamide, the antifolates piritrexim and pemetrexed (Alimta, LY231514), vinflunine and molecular targeting agents such as farnesyltransferase inhibitors (lonafarnib, R115777, SCH66336), ribozyme (RPI.4610), histone deacetylase inhibitor (CI-994) and monoclonal antibodies (epidermal growth factor receptor, Her 2/neu).

Solid-state NMR characterization of 69Ga and 71Ga in crystalline solids

Gallium model systems containing four- and six-coordinate gallium sites have been investigated using solid-state NMR. Measurement of the isotropic chemical shift and electric field gradient (EFG) have been performed at 9.4 T on alpha-Ga2O3, beta-Ga2O3, LiGaO2, NaGaO2, KGaO2, Ga2(SO4)3, and LaGaO3 using a variety of techniques on both NMR active nuclei (69Ga and 71Ga) including static, high speed magic-angle spinning (MAS), satellite transition (ST) spectroscopy, and rotor-assisted population transfer (RAPT). The chemical shift is found to correlate well with the coordination number, with four-coordinate gallium having values of approximately 50 ppm and six-coordinate gallium having values near 225 ppm (referenced to 1 M gallium nitrate solution). The magnitude of the EFG is found to be correlated to the distortion of the gallium polyhedra, with the strained systems having EFGs of 3 x 10(21) Vm(-2) or more, while the less strained systems have values of 1.5 x 10(21) Vm(-2) or less. A plot of chemical shift versus EFG suggests that solid-state NMR of gallium oxyanions can be more discriminating than liquid state NMR chemical shifts alone.

Effects of transferrin receptor blockade on cancer cell proliferation and hypoxia-inducible factor function and their differential regulation by ascorbate

Cellular iron is needed for cell survival and hydroxylation of hypoxia-inducible factor-1alpha (HIF-alpha) by prolyl hydroxylases (PHD). One mechanism of iron uptake is mediated by the cell surface transferrin receptor (TfR). Because iron is required for cell growth and suppression of HIF-alpha levels, we tested the effects of the two anti-TfR monoclonal antibodies (mAb) E2.3 and A27.15 on growth of breast cancer cells and induction of HIF-alpha and hypoxia-regulated genes. Treatment with both mAbs together synergistically inhibited cell proliferation in a dose-responsive manner by up to 80% following 8 days of exposure, up-regulated HIF-1alpha and HIF transcription targets, down-regulated TfR expression, and down-regulated cellular labile iron pool by 60%. Because combined treatment with anti-TfR mAbs resulted in the up-regulation of the hypoxia pathway, which may increase tumor angiogenesis, we analyzed the effects of ascorbate on cell viability and HIF-1alpha levels in cells treated with both anti-TfR mAbs together, as ascorbate has been shown to be required by PHD enzymes for full catalytic activity. Ascorbate at physiologic concentrations (25 micromol/L) suppressed HIF-1alpha protein levels and HIF transcriptional targets in anti-TfR mAb-treated cells but did not suppress the antiproliferative effect of the mAbs. These results indicate that the addition of ascorbate increased the activity of the PHD enzymes in down-regulating HIF but not the proliferation of iron-starved anti-TfR mAb-treated cells. The use of anti-TfR mAbs and ascorbate in inhibiting both cell proliferation and HIF-1alpha and angiogenesis under normoxic conditions may be of therapeutic use.

Resistance to the Antineoplastic Agent Gallium Nitrate Results in Marked Alterations in Intracellular Iron and Gallium Trafficking: Identification of Novel Intermediates

Gallium (Ga) shows significant antitumor activity by markedly interfering with iron (Fe) metabolism, and (67)Ga is used as a radio-imaging agent for cancer detection. Therefore, the mechanisms involved in (67)Ga uptake, metabolism, and resistance are critical to understand. The development of tumor lines that are gallium-resistant suggests (67)Ga uptake may be different in these cells, providing an opportunity for understanding intracellular (67)Ga and (59)Fe transport and gallium resistance. In this study, gallium-resistant cells were used to assess (67)Ga and (59)Fe uptake using native polyacrylamide gel electrophoresis autoradiography. In contrast to the common view that (67)Ga and (59)Fe use the same uptake pathways, we show that the trafficking of these two metal ions is different in cells either resistant (R) or sensitive (S) to gallium. Indeed, in contrast to (59)Fe, little (67)Ga is incorporated into ferritin, with most present as a labile (67)Ga pool. We also report unique changes in (67)Ga and (59)Fe trafficking between R and S cells. In particular, in R cells, there was a distinct transferrin-transferrin receptor 1-hemochromatosis protein (HFE) complex (band B) not observed in S cells. Furthermore, because HFE regulates iron and gallium uptake, the two Tf-TfR1-HFE complexes in R cells may be involved in reduced (67)Ga and (59)Fe uptake compared with S cells. In S cells, a novel iron-binding intermediate (band D) was identified that was not present in R cells and may be a "sensitivity factor" to gallium. In contrast to the general view that (67)Ga and (59)Fe use the same or similar uptake pathways, we show that their distribution and trafficking is markedly different in R and S cells.

Gallium compounds as antineoplastic agents

PURPOSE OF REVIEW

The purpose of this review is to provide an outline of the basic and clinical information on gallium nitrate as an antineoplastic agent. Although early clinical trials indicated that gallium nitrate had activity against lymphoma and bladder cancer, its subsequent development centered primarily on its effect on bone metabolism and not on its antineoplastic activity. As a result, the drug was approved for the treatment of hypercalcemia of malignancy. However, pharmaceutical production of gallium nitrate ceased during the late 1990s, bringing several gallium-based clinical trials to a halt. Gallium nitrate has recently become commercially available, thus reopening the door for clinical trials evaluating it as an antineoplastic agent.

RECENT FINDINGS

Multicenter clinical trials have recently been conducted to reevaluate gallium nitrate for the treatment of lymphoma. An oral formulation of gallium is also in development. Gallium's mechanisms of action include its binding to transferrin, targeting to transferrin receptors on lymphoma cells, and inhibiting ribonucleotide reductase. Recent investigations show that gallium activates caspases and induces apoptosis through the mitochondrial pathway, whereas complementary DNA microarray studies suggest that changes in intracellular trafficking pathways may be important in gallium resistance.

SUMMARY

Gallium nitrate has demonstrated activity against lymphoma and bladder cancer, which is likely the result of selective targeting of these malignancies. An important property of gallium nitrate is that it is not myelosuppressive and it lacks cross-resistance to other drugs. Further investigations are needed to understand better its molecular targets and to determine its clinical efficacy in combination with other drugs.

Effects of gallium on immune stimulation and apoptosis induction in human peripheral blood mononuclear cells

Gallium is commonly used in the semiconductor industry and medical field. Biologically, gallium is able to interrupt iron metabolism. Exposure to gallium has been shown to affect the human immune system. The purpose of this study was to investigate the in vitro biological effects of different gallium concentrations on cultured human peripheral blood mononuclear cells (PBMCs) in terms of cell growth, cytokine release, and apoptosis induction. In addition, the in vivo effects of gallium were analyzed by Wistar rat model. Our results revealed that low concentrations (1-10 microg/ml) of gallium promoted cells to enter the S phase of cell cycle and enhanced cellular release of tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma, both in vitro and in vivo. In contrast, high concentrations of gallium (50-100 microg/ml) induced apoptosis. Furthermore, gallium-induced cytokine release and apoptosis could be inhibited by iron-saturated transferrin (Tf-Fe). These results suggest that the concentration-dependent effects of gallium on PBMCs are related to iron metabolism.

Treatment of refractory urothelial carcinoma with alternating paclitaxel, methotrexate, cisplatin (TMP) and 5-fluorouracil, α-interferon, cisplatin (FAP)

We assessed the activity and safety of a biochemotherapy regimen in which courses of paclitaxel, methotrexate, and cisplatin were alternated with courses of 5-fluorouracil, alpha-interferon, and cisplatin in the treatment of refractory urothelial carcinoma. Forty patients were enrolled in the study. In the phase I portion, 15 patients were treated according to an escalating dosage regimen designed to determine the maximum tolerated dose. A total of 30 patients received treatment according to the maximum tolerated dose regimen: methotrexate (30 mg/m(2)) given iv on days 1 and 22; paclitaxel (175 mg/m(2)) given iv over 3 h on day 1; cisplatin (70 and 25 mg/m(2)) administered iv on days 1 and 22, respectively; 5-fluorouracil (400 mg/m(2)) given iv by continuous infusion daily for 5 days beginning on day 22; and alpha-interferon (4 mIU/m(2)) given SC daily for 5 days simultaneously with the 5-fluorouracil infusions. The regimen was repeated at 42-day intervals. The 40 treated patients had an overall response rate of 43%, a complete response rate of 18%, and a median survival time of 44 weeks. Most of the toxic effects were hematologic: Grade 4 neutropenia occurred in 30% of patients (12 patients) and Grade 3 thrombocytopenia in 20% (8 patients). Even though this alternating biochemotherapy regimen was active for patients with refractory urothelial carcinoma, its activity was not better than that of certain single cytotoxic agents. Furthermore, the complicated dosing schedule and toxic effects of the regimen precluded its routine use in the treatment of urothelial carcinoma.

Overview of advanced urothelial cancer trials of the Eastern Cooperative Oncology Group

Advanced transitional cell carcinoma of the urothelium is an aggressive malignancy characterized by a median survival period of less than 1 year. Although this disease is moderately chemotherapy-sensitive, to the authors' knowledge the impact of therapy reported to date on survival has been minimal. The authors presented an overview of the results from a series of clinical trials conducted over a 25-year period under the auspices of the Eastern Cooperative Oncology Group. They reviewed a series of antineoplastic agents identified by these studies with activity in advanced urothelial cancer and discussed current and future investigational goals and directions.

Feasibility trial of methotrexate-paclitaxel as a second line therapy in advanced urothelial cancer

To evaluate the clinical value of the concurrent use of methotrexate administered immediately before paclitaxel, we investigated the efficacy and toxicity of this two-drug combination administered as palliative second line therapy in patients with advanced urothelial cancer. The design of the schedule and sequence used was based on our previous preclinical data from a comparative study on sequential combinations of paclitaxel and methotrexate in a human bladder cancer cell line. As a confirmation study, we further extended our analysis of in vitro synergism. Twenty patients with advanced transitional cell carcinoma of the urinary tract previously treated with platinum-based therapy, with adequate renal function and a performance status > or = 60 were considered eligible. They received therapy with methotrexate 30 mg/m2 administered as an intravenous bolus, followed immediately by paclitaxel 175 mg/m2 given as a 3-hr infusion, both on day 1 every 21 days. Therapy was given on a compassionate-use basis until either disease progression was documented or the patient became intolerant to therapy. In vitro data were further analyzed using the median-effect principle and the combination index method. Twenty patients with metastatic (16 patients) or locally advanced disease (four patients) received a median of three cycles of therapy. Of the 19 patients assessable for response, there were six partial responses and seven disease stabilizations with no complete responses. Median duration of response was 3 months (range, 2-7) and median survival was 5 months. Three patients developed grade 3-4 neutropenia, one patient had grade 3 anemia, four patients had grade 2-3 sensory neuropathy, and three patients had myalgias. Eighteen patients developed alopecia. Gastrointestinal toxicity was mild. One patient died after the first cycle due to pulmonary thrombo-embolism and could not be evaluated for response. The synergistic in vitro effect of the concurrent combination was confirmed in analyses performed under mutually exclusive and mutually nonexclusive criteria. In conclusion, the combination of methotrexate and paclitaxel at this dose and sequence is feasible and active as a palliative therapy in patients with advanced urothelial cancer previously treated with platinum-based therapies. This schedule merits further investigation in a phase-II trial.

Gallium in cancer treatment

Gallium (Ga) is the second metal ion, after platinum, to be used in cancer treatment. Its activities are numerous and various. It modifies three-dimensional structure of DNA and inhibits its synthesis, modulates protein synthesis, inhibits the activity of a number of enzymes, such as ATPases, DNA polymerases, ribonucleotide reductase and tyrosine-specific protein phosphatase. Ga alters plasma membrane permeability and mitochondrial functions. Ga salts are taken up more efficiently and more specifically by tumour cells when orally administered. New compounds have been prepared: Ga maltolate, doxorubicin-Ga-transferrin conjugate and Tris(8-quinolinolato)Ga(III), which show interesting activities. Ga toxicity is well documented in vitro and in vivo in animals. In humans, the oral administration Ga is less toxic, and allows a chronic treatment, allowing an improvement of its bioavailability in tumours, by comparison with the parenteral use. The anticancer activity of Ga salts has been demonstrated but other effects have also been noted such as many bone effects that could be useful in bone metastatic patients. Its has also been shown that a long period of administration could induce tumour fibrosis. Ga is synergistic with other anticancer drugs. Although not as potent as platinum in vitro, the anticancer activity of Ga should not be ignored, but the schedule of administration still needs to be optimised and new compounds are now under clinical investigations.

Combination chemotherapy with gemcitabine and ifosfamide as second-line treatment in metastatic urothelial cancer. A phase II trial conducted by the Hellenic Cooperative Oncology Group

PURPOSE

The aim of the study was to evaluate the efficacy and safety of the combination of gemcitabine and ifosfamide as a second-line treatment for advanced urothelial cancer.

PATIENTS AND METHODS

Thirty-four patients with metastatic urothelial cancer previously treated with cisplatin (CDDP)/ carboplatin (CBDCA) and/or taxanes-based chemotherapy were studied. Gemcitabine was administered at a dose of 800 mg/m2 on days 1 and 8 and ifosfamide at a dose of 2 g/m2 on days 1 and 8 with adequate amount of Mesna. every three weeks. Hematopoietic growth factors were given between days 3 to 5 and 12 to 16 to maintain the treatment schedule.

RESULTS

On an intent to treat basis, there was one complete response (CR) (3%) (95% confidence interval (95% CI): 0% to 10%) and six partial responses (PR) (18%) (95% CI: 7% to 34%). inducing an objective response rate (RR) of 21% (95% CI: 9% to 38%); 12 (35%) patients achieved a stable disease (SD) and 15 (44%) a progressive disease (PD). The median time to tumor progression (TTP) was four months (range, 0.52 to 21.6 months) and the median survival nine months (range 0.52 to 28 months). This regimen also provided the opportunity for symptomatic improvement of pain, dysuria, haematuria and leg oedema. Grade 3-4 neutropenia was experienced by 9 (27%) patients, grade 3 4 anemia by 6 (18%) and grade 3-4 thrombocytopenia by 4 (12%). Six patients were hospitalized due to febrile neutropenia. Despite the prophylactic use of hematopoietic growth factors, 8 (23.5%) patients required dose reduction due to myelosuppression. Grade 3 alopecia occurred in 14 (41%) patients, grade 3-4 nausea in 1 (3%), grade 2 fever in 3 (9%), grade 2-3 diarrhea in 2 ( 6%) and grade 2 allergic reaction in 1 (3%).

CONCLUSION

We conclude that the combination of gemcitabine and ifosfamide is an active salvage regimen for the treatment of urothelial cancer and that the treatment also has a tolerable toxicity profile; it warrants further investigation in combination with CDDP in chemotherapy-naïve patients.

Differing sensitivity of tumor cells to apoptosis induced by iron deprivation in vitro

We studied the sensitivity of tumor cells to the induction of apoptosis by iron deprivation. Iron deprivation was achieved by the employment of a defined iron-deficient culture medium. Mouse 38C13 cells and human Raji cells die within 48 and 96 h of incubation in iron-deficient medium, respectively. On the contrary, mouse EL4 cells and human HeLa cells are completely resistant to the induction of death under the same experimental arrangement. Deoxyribonucleic acid fragmentation analysis by agarose gel electrophoresis as well as flow cytometric analysis after propidium iodide staining detected in 38C13 and Raji cells, but not in EL4 and HeLa cells, changes characteristic to apoptosis. The 38C13 cells, sensitive to iron deprivation, also displayed a similar degree of sensitivity to apoptosis induction by thiol deprivation (achieved by 2-mercaptoethanol withdrawal from the culture medium) as well as by rotenone (50 nM), hydroxyurea (50 microM), methotrexate (20 nM), and doxorubicin (100 nM). Raji cells shared with 38C13 cells a sensitivity to rotenone, methotrexate, doxorubicin, and, to a certain degree, to hydroxyurea. However, Raji cells were completely resistant to thiol deprivation. EI4 and HeLa cells, resistant to iron deprivation, also displayed a greater degree of resistance to most of the other apoptotic stimuli than did their sensitive counterparts. We conclude that some tumor cells in vitro are sensitive to apoptosis induction by iron deprivation, while other tumor cells are resistant. All the tumors found to be sensitive to iron deprivation in this study (four cell lines) are of hematopoietic origin. The mechanism of resistance to apoptosis induction by iron deprivation differs from the mechanism of resistance to thiol deprivation.

Topotecan in previously treated advanced urothelial carcinoma: an ECOG phase II trial

BACKGROUND

[corrected] Chemotherapeutic agents are playing an increasing role in the management of urothelial carcinoma. Despite recent advances in the treatment of this disease there continues to be a need to identify new active agents and their toxicity spectra. Topotecan is an agent as yet unstudied in bladder cancer.

METHODS

Ambulatory patients with progressive advanced urothelial carcinoma following prior systemic chemotherapy were treated with topotecan 1.5 mg/m2 intravenously (i.v.) daily for 5 days every three weeks for 6 cycles. Doses were modified for leukopenic fever, thrombocytopenic bleeding, and any grade 3 or 4 (NCI common toxicity criteria) toxicity.

RESULTS

Forty-four eligible patients entered the trial. There were 4 partial responses for an overall response rate of 9.1% (exact 95% two-stage binomial CI, 2.9% to 25.5%). Major identified toxicities were gastrointestinal and myelosuppression. There were no treatment-related deaths.

CONCLUSIONS

Topotecan at this dose and schedule has minimal activity in previously treated patients with advanced urothelial carcinoma. Toxicities can be severe but are manageable.

New approaches to treatment of metastatic bladder cancer

The combination of methotrexate, vinblastine, Adriamycin, and cisplatin (MVAC) has been the standard therapy for transitional cell carcinoma for over a decade. Despite evidence that MVAC can improve outcome in comparison with single drugs or other combinations in this disease, only a small fraction of patients (less than 4%) become long-term survivors, and the regimen is quite toxic. Attempts to improve upon the MVAC regimen have partially ameliorated its toxicity, but they have not clearly improved outcome. Recently, a number of new chemotherapeutic agents have become available. This report summarizes the current experience with these agents and combinations.

Gemcitabine/paclitaxel-based three-drug regimens in advanced urothelial cancer

Transitional cell carcinoma (TCC) of the urothelium is a highly chemosensitive tumour. Combination chemotherapy can provide both palliation and a modest survival advantage in patients with advanced disease. At present, the combination of cisplatin, methotrexate, doxorubicin and vinblastine (M-VAC) is the most widely used for advanced TCC with an overall response rate of 40-72% in phase II, and 35-45% in phase III studies, and a median survival of approximately 12 months. These modest results and the unsuccessful attempts to increase efficacy with dose intensive M-VAC schedules have prompted the identification of new active agents in TCC, such as the taxanes and gemcitabine. The overall response rates for two-drug regimens of cisplatin-paclitaxel, carboplatin-paclitaxel and cisplatin-gemcitabine range from 63 to 72%, 14 to 65% and 42 to 66%, respectively. The overall response rates for platinum-paclitaxel-gemcitabine three-drug regimens range from 58 to 80%. The potential clinical benefit of these new three-drug combinations in the treatment of TCC needs to be tested in future phase III studies.

[Chemotherapy for urothelial infiltrating tumors]

Since 1985, the gold standard regimen for metastatic tumours of the urothelial tract is a combination of methotrexate, vinblastine, doxorubicin and cisplatin (M-VAC protocol). Randomised studies have shown the superiority of the M-VAC regimen over cisplatin alone or in combination with cyclophosphamide and doxorubicin. The limited gain in survival shows that, although chemosensitive, metastatic tumours cannot be cured by the available drug combinations. Amongst new cytotoxic drugs in development, paclitaxel and gemcitabine are likely to be involved in the standard regimen of the future. The studies published to date do not support the routine use of chemotherapy in the neo-adjuvant or adjuvant setting for the management of early stage urothelial tumours.

Interaction of gallium nitrate with other inhibitors of ribonucleotide reductase: effects on the proliferation of human leukemic cells

Ribonucleotide reductase, a key enzyme in deoxyribonucleotide synthesis, is an important target for cancer chemotherapy. Drugs that inhibit its individual components may act synergistically to block DNA synthesis. Prior work has established that gallium inhibits the R2 subunit of ribonucleotide reductase. We show that gallium acts synergistically with the ribonucleotide reductase inhibitors gemcitabine and hydroxyurea to inhibit the proliferation of CCRF-CEM cells. In contrast, combinations of gallium with the ribonucleotide reductase inhibitors amidox, didox, or trimidox produced antagonistic effects on cell growth. Spectroscopy analysis revealed that as a result of their metal-binding properties, amidox, didox and trimidox formed complexes with gallium, thus negating potential synergistic actions. Our results have important implications in the design of clinical trials using these ribonucleotide reductase inhibitors in combination.

Transferrin Receptor-Dependent and -Independent Iron Transport in Gallium-Resistant Human Lymphoid Leukemic Cells

Recent studies showed that gallium and iron uptake are decreased in gallium-resistant (R) CCRF-CEM cells; however, the mechanisms involved were not fully elucidated. In the present study, we compared the cellular uptake of 59Fe-transferrin (Tf) and59Fe-pyridoxal isonicotinoyl hydrazone (PIH) to determine whether the decrease in iron uptake by R cells is caused by changes in Tf receptor (TfR)-dependent or TfR-independent iron uptake. We found that both 59Fe-Tf and 59Fe-PIH uptake were decreased in R cells. The uptake of 59Fe-Tf but not59Fe-PIH could be blocked by an anti-TfR monoclonal antibody. After 59Fe-Tf uptake, R cells released greater amounts of 59Fe than gallium-sensitive (S) cells. However, after 59Fe-PIH uptake 59Fe release from S and R cells was similar. 125I-Tf exocytosis was greater in R cells. At confluency, S and R cells expressed equivalent amounts of TfR; however, at 24 and 48 hours in culture, TfR expression was lower in R cells. Our study suggests that the decrease in Tf-Fe uptake by R cells is caused by a combination of enhanced iron efflux from cells and decreased TfR-mediated iron transport into cells. Furthermore, because TfR-dependent and -independent iron uptake is decreased in R cells, both uptake systems may be controlled at some level by similar regulatory signal(s).

Transferrin Receptor-Dependent and -Independent Iron Transport in Gallium-Resistant Human Lymphoid Leukemic Cells

Recent studies showed that gallium and iron uptake are decreased in gallium-resistant (R) CCRF-CEM cells; however, the mechanisms involved were not fully elucidated. In the present study, we compared the cellular uptake of 59Fe-transferrin (Tf) and59Fe-pyridoxal isonicotinoyl hydrazone (PIH) to determine whether the decrease in iron uptake by R cells is caused by changes in Tf receptor (TfR)-dependent or TfR-independent iron uptake. We found that both 59Fe-Tf and 59Fe-PIH uptake were decreased in R cells. The uptake of 59Fe-Tf but not59Fe-PIH could be blocked by an anti-TfR monoclonal antibody. After 59Fe-Tf uptake, R cells released greater amounts of 59Fe than gallium-sensitive (S) cells. However, after 59Fe-PIH uptake 59Fe release from S and R cells was similar. 125I-Tf exocytosis was greater in R cells. At confluency, S and R cells expressed equivalent amounts of TfR; however, at 24 and 48 hours in culture, TfR expression was lower in R cells. Our study suggests that the decrease in Tf-Fe uptake by R cells is caused by a combination of enhanced iron efflux from cells and decreased TfR-mediated iron transport into cells. Furthermore, because TfR-dependent and -independent iron uptake is decreased in R cells, both uptake systems may be controlled at some level by similar regulatory signal(s).

Vinblastine, ifosfamide, gallium nitrate, and filgrastim in platinum- and paclitaxel-resistant ovarian cancer: a phase II study

The authors performed a phase II trial of the VIG regimen (vinblastine, ifosfamide, and gallium nitrate) in patients who had advanced ovarian cancer who were refractory to cisplatin and/or carboplatin and whose disease had progressed after paclitaxel-based therapy. This was a heavily pretreated population, with five patients having received two to three prior chemotherapy regimens and six patients having received more than six prior chemotherapy regimens, with an average of 21 therapy cycles per patient. Fourteen patients were treated with vinblastine, 0.08 mg/kg intravenously on days 1 and 2; ifosfamide, 900 mg/m2 intravenously on days 1 through 5 with standard mesna uroprotection; and gallium nitrate administered as a continuous intravenous infusion at 225 mg/m2 per 24 hours x 120 hours. Granulocyte colony-stimulating factor (G-CSF) was administered subcutaneously at 5 microg/kg/day beginning on day 7 until day 13. Five of 14 patients achieved a partial response for an overall response rate of 36% (95% confidence interval, 14%-68%). The median response duration was 14 weeks. Toxicity was primarily hematologic, with anemia and leukopenia being most significant. There were no treatment-related deaths. Further evaluation of this regimen in a less heavily pretreated population is warranted.

Paclitaxel plus gallium nitrate and filgrastim in patients with refractory malignancies: a phase I trial

To determine the maximally tolerated dose of paclitaxel with and without filgrastim (G-CSF) when administered as a 24-hour intravenous infusion after a 120-hour infusion of gallium nitrate at a fixed dose of 300 mg/m2/24 hours, 40 patients were entered onto a trial lasting from September 1994 to September 1996. Eligibility included a diagnosis of an advanced malignancy not amenable to curative therapy and up to one previous chemotherapy regimen for metastatic disease. Gallium was administered at a fixed dose of 300 mg/m2/day as a continuous intravenous infusion for 120 hours. Paclitaxel starting at 90 mg/m2 was given concurrently with the last 24 hours of the gallium as a 24-hour intravenous infusion. Cycles were repeated every 21 days. Once the maximum tolerated dose (MTD) of paclitaxel was reached, G-CSF (5 microg/kg/day days 7-16) was added and paclitaxel dose escalation continued. The MTD for paclitaxel without G-CSF was 110 mg/m2 and 225 mg/m2 with G-CSF, with neutropenia being the dose-limiting toxicity. A partial response was noted in a patient who had thymoma and a complete response was achieved in a patient who had colon cancer. The recommended phase II dosage is gallium nitrate at 300 mg/m2/day over 120 hours, with paclitaxel at 110 mg/m2 over 24 hours without G-CSF or 225 mg/m2 over 24 hours with G-CSF and 0.5 mg calcitriol on days 1 through 7. Further trials of this modified regimen for outpatient administration are in progress.

Antineoplastic drugs that interfere with iron metabolism in cancer cells

Normal iron metabolism can be perturbed with iron chelators, toxic metals that bind to transferrin, toxic metals bound to transferrin or antineoplastic agents covalently linked to transferrin. These agents cause significant inhibition of tumor cell growth in cell culture and have been shown to have significant in vivo antineoplastic activity. Cell culture studies showed that deferoxamine mesylate inhibits cell growth and division in both the MCF-7 human breast and HeLa human cervical carcinoma cell lines. Animal studies demonstrated that when deferoxamine mesylate is injected intravenously into rats that are on a low iron diet, there is a significant reduction in the growth of 13762NF mammary adenocarcinomas. Gallium, indium and the antineoplastic agent cisplatin were bound to the iron binding site of transferrin and inhibit the growth of malignant carcinoma cell lines. Gallium-transferrin and indium-transferrin were at least 10 times more inhibitory to both MCF-7 and HeLa cell lines than their free salts. Further cell culture studies demonstrated that cisplatin-transferrin complexes act synergistically with doxorubicin to inhibit the growth of cultured MCF-7 cells. In a Phase I clinical trial of cisplatin-transferrin complex there was a 36% (four of 11 patients) response rate in breast cancer patients with advanced disease. In a second clinical study the sequential administration of deferoxamine mesylate (2 days at 6 g/day in 8 hrs), cisplatin-transferrin complex (7 days at 500 mg/day) and FAC (5-fluorouracil, doxorubicin and cyclophosphamide at 450, 45 and 450 mg/m2, respectively) to advanced breast cancer patients resulted in partial responses in seven of eight patients treated. Future work will concentrate on substituting transferrin based agents with daunorubicin or doxorubicin attached to the surface of the transferrin, and gallium or indium bound to the iron binding site, to increase efficacy of the second component of the sequential combination chemotherapy.

Gallium nitrate optic neuropathy

PURPOSE

To report a patient with visual loss after systemic administration of gallium nitrate.

METHOD

Case report.

RESULTS

After receiving intravenous gallium nitrate, a 77-year-old man developed bilateral visual loss and optic neuropathy with central scotomas on visual field testing and diminished P2-wave amplitude on visual evoked potential examination. The condition worsened after oral corticosteroid therapy. Partial recovery of optic nerve function in both eyes was present after 12 months of oral ferrous sulfate administration.

CONCLUSIONS

Partially reversible bilateral optic neuropathy may occur after administration of gallium nitrate in the absence of other chemotherapeutic agents. Ophthalmic examinations are indicated in patients who receive gallium nitrate.

Systemic chemotherapy of transitional cell carcinoma of the urothelium

Although the incidence of bladder cancer has increased in recent years, survival has also improved. Chemotherapy has made a substantial impact on this disease and now is used in patients with advanced or metastatic disease as well as in select patients with high-risk muscle invasive disease. While cisplatin remains the most active single antineoplastic agent, several other agents including methotrexate, vinblastine, and Adriamycin (doxorubicin) have important activity. More recently, paclitaxel and gemcitabine have shown promising activity in bladder cancer. Multidrug combination therapy has provided more frequent and durable responses than single agent therapy. Regimens containing cisplatin and methotrexate have been shown to be most effective in the treatment of advanced disease. Adjuvant chemotherapy regimes typically have included cisplatin or cisplatin and methotrexate combinations. However, studies have been limited and further prospective trials are required to determine the role of adjuvant chemotherapy. Multiple studies have investigated neoadjuvant chemotherapy with cisplatin and methotrexate combinations or anthracycline-based regimens, but study results are mixed. Further trials will be required to define the role of neoadjuvant chemotherapy in bladder cancer.

Resistance to the antitumor agent gallium nitrate in human leukemic cells is associated with decreased gallium/iron uptake, increased activity of iron regulatory protein-1, and decreased ferritin production

The mechanism of drug resistance to gallium nitrate is not known. Since gallium can be incorporated into ferritin, an iron storage protein that protects cells from iron toxicity, we investigated whether ferritin expression was altered in gallium-resistant (R) CCRF-CEM cells. We found that the ferritin content of R cells was decreased, while heavy chain ferritin mRNA levels and iron regulatory protein-1 (IRP-1) RNA binding activity were increased. IRP-1 protein levels were similar in gallium-sensitive (S) and R cells, indicating that R cells contain a greater proportion of IRP-1 in a high affinity mRNA binding state. 59Fe uptake and transferrin receptor expression were decreased in R cells. In both S and R cells, gallium inhibited cellular 59Fe uptake, increased ferritin mRNA and protein, and decreased IRP-1 binding activity. Gallium uptake by R cells was markedly diminished; however, the sensitivity of R cells to gallium could be restored by increasing their uptake of gallium with excess transferrin. Our results suggest that R cells have developed resistance to gallium by down-regulating their uptake of gallium. In parallel, iron uptake by R cells is also decreased, leading to changes in iron homeostasis. Furthermore, since gallium has divergent effects on iron uptake and ferritin synthesis, its action may also include a direct effect on ferritin mRNA induction and IRP-1 activity.

5-Fluorouracil, interferon-alpha-2b and cisplatin (FAP) for advanced urothelial cancer. A phase II study. Hellenic Co-operative Oncology Group

PURPOSE

To evaluate the efficacy and toxicity of the FAP combination chemotherapy as first-line treatment in advanced urothelial cancer.

PATIENTS AND METHODS

Thirty-four patients with histologically confirmed advanced urothelial cancer, with measurable disease and without previous chemotherapy entered the study; all 34 are evaluable. The 28 males and 6 females had a median age of 65 (19-75) and a median ECOG performance status of 1 (0-2). Twenty-eight patients had bladder cancer, four had renal pelvic cancer and two ureteral cancer. Thirty patients had transitional cell carcinoma and four mixed, mostly of grade 3. Sites of disease included lymph nodes (18), bladder (9), liver (9), pelvic mass (9), lung (7), etc. The treatment plan was as follows: 5-fluorouracil 500 mg/m2 continuous infusion D1-D5 and D22-D26; interferon-alpha-2b 5 million i.u./m2 D1-D5 followed by 3x/week and then D22-D26; cisplatin 25 mg/m2 D1, D8, D15, D22. Cycles were repeated every 36 days.

RESULTS

The median number of cycles administered was 3 (1-6). The relative dose intensities for 5-fluorouracil, interferon and cisplatin were 76%, 71% and 75%, respectively. Twenty-two of 34 patients (65%, 95% confidence interval [95% CI], 46% to 80%) had objective responses, including six complete clinical responses (CR) (18%, 95% CI, 7% to 35%) and 16 partial responses (PR) (47%, 95% CI, 30% to 65%). Three patients had stable disease and seven progressed. Two patients discontinued treatment after the first cycle because of toxicity. The median survival is 15.30 months (1.40-37.60), the median time to progression 11.60 months (4.13-37.60), and the median survival of complete responders 20.75+ months (8+ to 38+). The only significant hematologic toxicity was the grade 3-4 neutropenia in 44%. Non-hematologic toxic effects were unremarkable.

CONCLUSION

The FAP combination as first-line chemotherapy is highly active in the treatment of advanced urothelial cancer, and has limited toxicity. Further phase III studies are in progress to compare FAP and M-VAC.

Evaluation of continuous-infusion gallium nitrate and hydroxyurea in combination for the treatment of refractory non-Hodgkin's lymphoma

Based on preclinical studies demonstrating synergy between gallium and hydroxyurea, we evaluated the efficacy and toxicity of continuous intravenous gallium nitrate in combination with oral hydroxyurea in patients with refractory non-Hodgkin's lymphoma. Fourteen patients, median age 64 years (range 53-89), with stage III or IV low- or intermediate-grade lymphoma were treated with gallium nitrate and hydroxyurea in combination for 7 days at four different dose levels: (a) gallium nitrate, 200 mg/m2/day; hydroxyurea, 500 mg/day; (b) gallium nitrate, 250 mg/m2/day; hydroxyurea, 1,000 mg/day; (c) gallium nitrate, 300 mg/m2/day; hydroxyurea, 1,000 mg/day; and (d) gallium nitrate, 350 mg/m2/day, hydroxyurea, 1,000 mg/day. All patients had progressive disease and had been heavily pretreated. Six of 14 patients had objective tumor regression following treatment (one complete response, one near-complete response, and four partial responses) with a median duration of response of 7 weeks (range 3-38 weeks). An additional four patients had minor responses. Responses occurred at all dose levels and in both low- and intermediate-grade histologic subtypes. The predominant toxicities encountered were anemia and reversible nephrotoxicity. Combination gallium nitrate and hydroxyurea has significant activity in lymphoma and is well tolerated even by elderly patients. Because of the lack of cross-resistance to other drugs and the potential synergistic antineoplastic activity, gallium nitrate and hydroxyurea should be further evaluated in combination with other chemotherapeutic agents.

Metastatic bladder cancer: advances in treatment

At present, a combination of cisplatin, methotrexate, vinblastine and doxorubicin is the most widely used chemotherapy for metastatic bladder cancer. However, long-term follow-up shows that this combination may have little effect on survival. In addition, this regimen is toxic. New agents are needed which combine efficacy with good safety profiles. Agents which have been investigated include gallium nitrate, interferon-alpha and paclitaxel both as single agents and in combination with established cytotoxic drugs. A number of studies have been conducted in bladder cancer with the novel nucleoside analogue, gemcitabine. Response rates of up to 33% have been recorded in two phase II studies. Gemcitabine was well tolerated in both studies with few of the side-effects normally associated with cytotoxic drugs. A third study is ongoing.

New approaches in the treatment of metastatic transitional-cell cancer of the bladder

In recent years, chemotherapy of metastatic transitional-cell carcinoma of the bladder has advanced from the use of individual therapeutic agents, which has effected only rare responses, to the development of multi-agent regimens, which have greatly improved both partial and complete response rates, resulting in improved local care, palliation, and; perhaps, survival. However, because of the limited duration of response, frequent recurrences, and the significant proportion of patients with refractory disease, there have been only modest overall gains in long-term disease-free survival. These shortcomings have prompted investigation of alternative approaches to current combination chemotherapy regimens, including the use of hematopoietic growth factors and novel single-agent, multi-agent, and gene therapy protocols.

In vitro investigations of new therapeutic agents on bladder tumor cell lines

In this study sensitivity of human transitional cancer cells to the anticancer agent paclitaxel, an antimicrotubular drug, and to gallium nitrate, a group IIIa metal, was compared to that of the standard MVAC (methotrexate, vinblastine, doxorubicin and cisplatin) drugs. The reduction of cell proliferation was evaluated after 48 h of incubation of six different cell lines with each agent using the mean transit time (MTT) assay. We investigated both monolayers and spheroids. Paclitaxel showed significantly higher growth inhibitory effects on monolayers than vinblastine, both agents targeting the antimicrotubular apparatus. This could not be reproduced on spheroids, where a survival fraction of 50% was observed even at high concentrations (10 microM). High concentrations of gallium nitrate were needed to achieve sufficient toxicity. These concentrations are beyond the concentration achievable by systemic application. Our findings suggest that paclitaxel may be a clinically useful agent for systemic and intravesical use in bladder cancer.

Paclitaxel in advanced urothelial carcinoma: its role in patients with renal insufficiency and as salvage therapy

PURPOSE

We evaluated the role of paclitaxel in patients with advanced urothelial carcinoma and renal insufficiency or as second line therapy for metastatic disease.

MATERIALS AND METHODS

Nine patients with advanced urothelial carcinoma received 175 to 250 mg./m2. paclitaxel intravenously as a 24-hour infusion. Six patients had renal insufficiency with a median serum creatinine of 2.25 mg./dl. (range 1.9 to 3.2) and 3 with normal renal function were treated after disease progression following 1 to 2 prior chemotherapy regimens.

RESULTS

Of 9 patients 5 (56%) achieved a partial response, including 4 of 6 with renal insufficiency. Toxicity was primarily hematological with 4 patients experiencing febrile neutropenia. There was no adverse impact on renal function.

CONCLUSIONS

Paclitaxel as a single agent represents an effective therapeutic alternative for patients with advanced transitional cell carcinoma of the urothelium and renal insufficiency precluding cisplatin or gallium nitrate based chemotherapy. Additionally, paclitaxel appears to be effective in patients in whom prior cisplatin based therapy failed.