Flexibility and efficacy of automatic continuous fluorodeoxyuridine infusion in metastases from a renal cell carcinoma

Poly(ADP-Ribose) polymerase inhibition synergizes with 5-fluorodeoxyuridine but not 5-fluorouracil in ovarian cancer cells

5-Fluorouracil (5-FU) and 5-fluorodeoxyuridine (FdUrd, floxuridine) have activity in multiple tumors, and both agents undergo intracellular processing to active metabolites that disrupt RNA and DNA metabolism. These agents cause imbalances in deoxynucleotide triphosphate levels and the accumulation of uracil and 5-FU in the genome, events that activate the ATR- and ATM-dependent checkpoint signaling pathways and the base excision repair (BER) pathway. Here, we assessed which DNA damage response and repair processes influence 5-FU and FdUrd toxicity in ovarian cancer cells. These studies revealed that disabling the ATM, ATR, or BER pathways using small inhibitory RNAs did not affect 5-FU cytotoxicity. In stark contrast, ATR and a functional BER pathway protected FdUrd-treated cells. Consistent with a role for the BER pathway, the poly(ADP-ribose) polymerase (PARP) inhibitors ABT-888 (veliparib) and AZD2281 (olaparib) markedly synergized with FdUrd but not with 5-FU in ovarian cancer cell lines. Furthermore, ABT-888 synergized with FdUrd far more effectively than other agents commonly used to treat ovarian cancer. These findings underscore differences in the cytotoxic mechanisms of 5-FU and FdUrd and suggest that combining FdUrd and PARP inhibitors may be an innovative therapeutic strategy for ovarian tumors.

Differential gene expression identifies subgroups of renal cell carcinoma

Clear cell carcinoma of the kidney, the most common subtype of renal cell cancer, displays different biological behavior in different patients. This heterogeneity cannot be recognized by light microscopy. In this study, gene expression in 16 clear cell renal cell carcinoma samples and 17 non-malignant tissue types comprising 539 samples was determined using oligonucleotide microarrays representing approximately 40,000 known genes and ESTs. Differences in gene expression were quantified as the fold change in gene expression between the various sets of samples. A set of genes was identified that was overexpressed in the renal cell carcinoma samples compared with the normal kidney samples. Principle component analysis of the set of renal cell carcinomas using this set of genes overexpressed in renal cell cancer revealed the existence of 2 major subgroups among the renal carcinomas. A series of principle component analyses of the set of renal cell carcinomas using different gene sets composed of genes involved in different metabolic pathways also revealed the same 2 major subgroups of the renal cell cancers. Eisen clustering using the same genes also revealed the same 2 major renal cell cancer subsets. Review of the pathology suggested that these 2 subgroups differed in pathologic grade. Genes differentially expressed between the 2 renal cell cancer subsets were identified. Examination of gene expression in each renal cell cancer subset and the pool of renal cell carcinoma samples compared with that in 17 different normal tissues revealed genes specifically overexpressed in renal cell cancer compared with these normal tissues. The authors conclude that gene expression patterns may be useful in helping to further classify subtypes of renal cell carcinoma that may have clinical significance. In addition, the genes identified as overexpressed in each set of clear cell renal cell carcinomas compared with normal tissues may represent useful targets for therapy.

Novel advances in drug delivery to brain cancer

The therapy of brain tumors has been limited by a lack of effective methods of drug delivery to the brain. Systemic administration is often associated with toxic side effects and ultimately fails to achieve therapeutic concentrations within a tumor. An attractive strategy that has gained importance in brain tumor therapy has relied on local and controlled delivery of chemotherapeutic agents by biodegradable polymers. This technique allows direct exposure of tumor cells to a therapeutic agent for a prolonged period of time and has been shown to prolong the survival of patients with malignant brain tumors. The use of polymers for local drug delivery greatly expands the spectrum of drugs available for the treatment of malignant brain tumors. This review discusses the rationale for local drug delivery, describes the development of currently available polymer-based therapeutic agents, and highlights examples of promising non-polymer based drug delivery methods for use in the treatment of malignant brain tumors.

Local drug delivery to the brain

The controlled local delivery of antineoplastic agents by biodegradable polymers is a technique that allows for exposure of tumor cells to therapeutic doses of an active agent for prolonged periods of time while avoiding high systemic doses associated with debilitating toxicities. The use of polymers for chemotherapy delivery expands the spectrum of available treatment of neoplasms in the central nervous system, and facilitates new approaches for the treatment of malignant gliomas. In this article, we discuss the rationale and history of the development and use of these polymers, and review the various agents that have used this technology to treat malignant brain tumors.

Simplified chronomodulated continuous infusion of floxuridine in patients with metastatic renal cell carcinoma

BACKGROUND

Numerous preclinical and clinical trials showed that circadian-modified 5-fluoro-2-deoxyuridine (floxuridine; FUdR) infusion administered with a totally implantable programmable pump is associated with lower toxicity, higher dose intensity, and improved therapeutic outcome in renal cell carcinoma (RCC).

METHODS

Between July 1988 and March 1991, the authors treated 30 patients with metastatic RCC with circadian-timed infusion FUdR at 0.15 mg/kg/day x 14 days at monthly intervals with a programmable portable pump. Time modification was simplified with one-third of the daily dose given between 11 p.m. and 11 a.m. and two-thirds given between 11 a.m. and 11 p.m. The characteristics of the patients were as follows: 19 men; 11 women; median age, 60 years (range, 28-82 years); median World Health Organization (WHO) performance status: 2 (range: 0-3); 77% failed prior systemic treatment. The main sites of tumor involvement were lungs (70%) and bone (53%).

RESULTS

One hundred twenty-eight cycles were completed (median, 3 cycles per patient; range: 1-18 cycles per patient). Toxicity developed in 10 (33%) patients, primarily Grade 1-2 nausea/vomiting (6 patients), Grade 3 diarrhea (3 patients), and Grade 2 hand-foot syndrome (1 patient). In 28 patients evaluable for response, the authors observed four partial responses (14%; 95% confidence interval, 4-33%) and five stabilizations of the disease, including three minor responses. The median duration of response was 12 months (range, 8-24 months), and the median survival time was 6 months.

CONCLUSION

Circadian continuous infusion FUdR may be an effective outpatient treatment for metastatic RCC, with low toxicity and good quality of life in responding patients.