Neuroprotective effect of reduced glutathione on cisplatin-based chemotherapy in advanced gastric cancer: a randomized double-blind placebo-controlled trial

Neuroprotective effect of reduced glutathione on oxaliplatin-based chemotherapy in advanced colorectal cancer: a randomized, double-blind, placebo-controlled trial

PURPOSE

We performed a randomized, double-blind, placebo-controlled trial to assess the efficacy of glutathione (GSH) in the prevention of oxaliplatin-induced neurotoxicity.

PATIENTS AND METHODS

Fifty-two patients treated with a bimonthly oxaliplatin-based regimen were randomized to receive GSH (1,500 mg/m(2) over a 15-minute infusion period before oxaliplatin) or normal saline solution. Clinical neurologic evaluation and electrophysiologic investigations were performed at baseline and after four (oxaliplatin dose, 400 mg/m(2)), eight (oxaliplatin dose, 800 mg/m(2)), and 12 (oxaliplatin dose, 1,200 mg/m(2)) cycles of treatment.

RESULTS

At the fourth cycle, seven patients showed clinically evident neuropathy in the GSH arm, whereas 11 patients in the placebo arm did. After the eighth cycle, nine of 21 assessable patients in the GSH arm suffered from neurotoxicity compared with 15 of 19 in the placebo arm. With regard to grade 2 to 4 National Cancer Institute common toxicity criteria, 11 patients experienced neuropathy in the placebo arm compared with only two patients in the GSH arm (P =.003). After 12 cycles, grade 2 to 4 neurotoxicity was observed in three patients in the GSH arm and in eight patients in the placebo arm (P =.004). The neurophysiologic investigations (sural sensory nerve conduction) showed a statistically significant reduction of the values in the placebo arm but not in the GSH arm. The response rate was 26.9% in the GSH arm and 23.1% in the placebo arm, showing no reduction in activity of oxaliplatin.

CONCLUSION

This study provides evidence that GSH is a promising drug for the prevention of oxaliplatin-induced neuropathy, and that it does not reduce the clinical activity of oxaliplatin.

Cardiomyopathy Caused by Antineoplastic Therapies

The goals of care for patients at risk for cardiomyopathy induced by cancer treatment should include prevention, early diagnosis, treatment of subclinical cardiac dysfunction, prevention of disease progression, and prolongation of patient survival. Any strategy aimed to minimize the cardiotoxic effects of cancer treatment should maintain the treatment's antineoplastic efficacy. Successful therapy achieves the highest health-related quality of life that is defined by the balance between maximizing the efficacy of oncologic therapy and minimizing the toxicity of this therapy. Doxorubicin-induced cardiotoxicity can be reduced by limiting the overall cumulative dose. There is no specific treatment for cancer therapy-related cardiomyopathy, and symptomatic patients should receive standard treatments for congestive heart failure such as afterload reduction, beta-blockers, diuresis, and digoxin. Afterload reduction with angiotensin-converting enzyme inhibitors such as enalapril and captopril may be indicated in patients with elevated afterload and asymptomatic left ventricular dysfunction diagnosed by echocardiography. Beta-blockers may improve myocardial systolic dysfunction and may be useful in the treatment of cancer treatment-induced cardiomyopathy. Cardiac transplantation remains a viable option in patients with cancer treatment-induced end-stage heart disease.

Dietary antioxidants during cancer chemotherapy: impact on chemotherapeutic effectiveness and development of side effects

Several studies suggest that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that results from treatment with antineoplastic agents. Administration of antineoplastic agents results in oxidative stress, i.e., the production of free radicals and other reactive oxygen species (ROS). Oxidative stress reduces the rate of cell proliferation, and that occurring during chemotherapy may interfere with the cytotoxic effects of antineoplastic drugs, which depend on rapid proliferation of cancer cells for optimal activity. Antioxidants detoxify ROS and may enhance the anticancer effects of chemotherapy. For some supplements, activities beyond their antioxidant properties, such as inhibition of topoisomerase II or protein tyrosine kinases, may also contribute. ROS cause or contribute to certain side effects that are common to many anticancer drugs, such as gastrointestinal toxicity and mutagenesis. ROS also contribute to side effects that occur only with individual agents, such as doxorubicin-induced cardiotoxicity, cisplatin-induced nephrotoxicity, and bleomycin-induced pulmonary fibrosis. Antioxidants can reduce or prevent many of these side effects, and for some supplements the protective effect results from activities other than their antioxidant properties. Certain side effects, however, such as alopecia and myelosuppression, are not prevented by antioxidants, and agents that interfere with these side effects may also interfere with the anticancer effects of chemotherapy.

Plasma antioxidant status after high-dose chemotherapy: a randomized trial of parenteral nutrition in bone marrow transplantation patients

BACKGROUND

Chemotherapy and radiation therapy result in increased free radical formation and depletion of tissue antioxidants. It is not known whether parenteral nutrition (PN) administered during bone marrow transplantation (BMT) supports systemic antioxidant status.

OBJECTIVE

The aims of the study were to determine 1) whether high-dose chemotherapy decreases concentrations of major circulating antioxidants in patients undergoing BMT and 2) whether administration of standard PN maintains systemic antioxidant concentrations compared with PN containing micronutrients and minimal lipids alone.

DESIGN

Twenty-four BMT patients were randomly assigned to receive either standard PN containing conventional amounts of dextrose, amino acids, micronutrients, and lipid (120 kJ/d) or a solution containing only micronutrients (identical to those in standard PN) and a small amount of lipid (12 kJ/d). Plasma antioxidant status was measured before conditioning therapy and serially at days 1, 3, 7, 10, and 14 after BMT.

RESULTS

Plasma glutathione (GSH) and alpha- and gamma-tocopherol concentrations decreased and the GSH redox state became more oxidized after conditioning chemotherapy. Plasma cysteine concentrations were unchanged, whereas cystine concentrations increased. Plasma vitamin C and zinc concentrations and GSH peroxidase activity increased over time. Plasma alpha-tocopherol concentrations were lower in patients given standard PN. There were no differences in other plasma antioxidants between groups.

CONCLUSIONS

A significant decline in GSH-glutathione disulfide, cysteine-cystine, and vitamin E status occurs after chemotherapy and BMT. Standard PN does not improve antioxidant status compared with administration of micronutrients alone. Further evaluation of PN formulations to support patients undergoing high-dose chemotherapy and BMT are needed.

Platinum neurotoxicity: clinical profiles, experimental models and neuroprotective approaches

This paper reviews the neurotoxic side-effects associated with platinum drugs, experimental approaches to studying this toxicity and attempts to use neuroprotective agents in conjunction with platinum drugs. Platinum drugs differ in their neurotoxicity profiles in patients. The frequency, severity, mode of onset and reversibility of peripheral nerve toxicity varies between different platinum analogues. Animal models, primary cultures of dorsal root ganglia neurons and tumour cell-lines of neuronal origin are being used in attempts to identify potential treatments for platinum-induced neurotoxicity. To date, clinical trials have been hampered by the poor tolerance of neuroprotective treatments and failure to achieve reversal of platinum drug neurotoxicity with thiols, neurotrophic factors or calcium channel blockers.

Randomized study of a short course of weekly cisplatin with or without amifostine in advanced head and neck cancer. EORTC Head and Neck Cooperative Group

BACKGROUND

Cisplatin is one of the most active cytotoxic agents available for the treatment of patients with head and neck cancer. In a previous phase II study with weekly administration of cisplatin, a response rate of 51% was achieved. However, only in a minority of the patients the planned high dose intensity of 80 mg/m2/week could be reached because of toxicity, mainly thrombocytopenia and ototoxicity. Amifostine is a cytoprotective drug that can diminish the toxicity of alkylating agents and platinum compounds. Therefore the effect of amifostine on toxicity and activity of weekly cisplatin was investigated in a randomized study.

PATIENTS AND METHODS

Patients with locally advanced, recurrent or metastatic head and neck cancer were eligible. Patients were randomized to weekly cisplatin 70 mg/m2 for six cycles preceded by amifostine 740 mg/m2, or cisplatin only. Cisplatin was administered in hypertonic saline (3% NaCl) as a one-hour infusion; amifostine was administered as a 15-minute infusion directly before the administration of cisplatin.

RESULTS

Seventy-four patients were entered in the study. The median number of cisplatin administrations was 6 (range 2-6), equal in both arms. In both treatment arms the median dose intensity of cisplatin achieved was the planned 70 mg/m2/week. In the cisplatin only arm 6 out of 206 cycles were complicated by thrombocytopenia grade 3 or 4 versus 1 of 184 cycles in the amifostine arm (P = 0.035). Hypomagnesaemia grade 2 + 3 was significantly less observed in the amifostine arm (P = 0.04). Neurotoxicity analyzed by serial vibration perception thresholds (VPT) showed a diminished incidence of subclinical neurotoxicity in the amifostine arm (P = 0.03). No protective effect on renal and ototoxicity could be shown. Hypotension was the main side effect of amifostine but only of relevance in one patient. The antitumor activity of cisplatin was preserved as 63% of the evaluable patients in the amifostine arm responded compared to 50% of the evaluable patients in the cisplatin alone arm.

CONCLUSION

Our study indicated that in combination with weekly administered cisplatin amifostine reduced the risk of thrombocytopenia, hypomagnesemia as well as subclinical neurotoxicity, but did not result in a higher dose intensity of cisplatin. Addition of amifostine did not compromise the antitumor effect of cisplatin.

Intensive weekly chemotherapy is not effective in advanced pancreatic cancer patients: a report from the Italian Group for the Study of Digestive Tract Cancer (GISCAD)

Twenty-two patients, with locally advanced unresectable and/or metastatic pancreatic carcinoma, received weekly administration of cisplatin 40 mg m(-2), 5-fluorouracil 500 mg m(-2), epidoxorubicin 35 mg m(-2), 6S stereoisomer of leucovorin 250 mg m(-2) and glutathione 1.5 mg m(-2), supported by a daily administration of lenograstim at a dose of 5 microg kg(-1). Nineteen patients were men and three were women. Median age was 63 years (range 47-70). At study entry, pain was present in 15 out of 22 patients (68%) with a mean value of Scott-Huskisson scale of 27.6+/-23.8, whereas a weight loss >10% was present in 15 patients. After eight weekly treatments, three partial responses were achieved for a response rate of 13% (95% CI 0-26%), five patients had stable disease and 14 progressed on therapy. Pain was present in 9 out of 22 patients (40%) with a mean value of Scott-Huskisson scale of 12.3+/-18.4. Eight patients (36%) (three partial response and five stable disease) had a positive weight change. Toxicity was mild: WHO grade III or IV toxicity was recorded in terms of anaemia in 7 out of 188 cycles (3.7%), of neutropenia in 9 out of 188 cycles (4.7%) and of thrombocytopenia in 3 out of 188 cycles (1.5%). Median survival of all patients was 6 months. The outcome of this intensive chemotherapy regimen does not support its use in pancreatic cancer.

Cytoprotection in the treatment of pediatric cancer: review of current strategies in adults and their application to children

BACKGROUND

The protection of patients from the acute and/or chronic toxicity of antineoplastic therapy has become a major concern of oncology centers around the world. However, most of the effort has been directed toward the adult population, and limited studies have been performed in the group that may gain the most from such strategies, namely, children.

PROCEDURES

The MedLine and CancerLit databases were surveyed, and the relevant biomedical literature on cytoprotection during antineoplastic treatment was analyzed.

RESULTS

Cytotoxicity from antineoplastic therapy customarily is addressed by altering dosing schedules, a technique that can seriously impact the efficacy of the therapy. Colony stimulating factors have been used posttherapy to stimulate recovery from neutropenia, and various agents have been proposed as pretherapy cytoprotectors. Trials in adults have produced mixed results, and, to date, only amifostine and dexrazoxane have been approved as cytoprotectors for very narrow indications. Few trials have been performed in children, although these patients often can look forward to long-term remission.

CONCLUSIONS

To prevent permanent toxicities from antineoplastic therapies that impact long-term pediatric survivors, the experience gained in adults should be extended more aggressively to children, and formal, randomized trials should be performed to determine the type of protection most suitable for the pediatric population.

Intensive weekly chemotherapy for locally advanced gastric cancer using 5-fluorouracil, cisplatin, epidoxorubicin, 6S-leucovorin, glutathione and filgrastim: a report from the Italian Group for the Study of Digestive Tract Cancer (GISCAD)

Local extension prevents curative resection in more than two-thirds of gastric cancer patients. Unfortunately, resectability is one of the main prognostic factors in these patients, and survival is longer when tumours are completely removed. Preoperative chemotherapy is an attractive concept for obtaining curative resection. Thirty-two locally advanced unresectable gastric cancer patients were enrolled in five Italian Group for the Study of Digestive Tract Cancer (GISCAD) centres. For 16 patients, surgical unresectability was based on computerized tomography scan evaluation of tumour size (four patients) and invasion of adjacent structures (12 patients), whereas in another 16 patients locally advanced disease was confirmed by laparotomy. They received weekly administration of cisplatin 40 mg m(-2), 5-fluorouracil 500 mg m(-2), epidoxorubicin 35 mg m(-2), 6S-stereoisomer of leucovorin 250 mg m(-2) and glutathione 1.5 g m(-2). From the day after to the day before each chemotherapy administration, filgrastim was administered by subcutaneous injection at a dose of 5 microg kg(-1). One cycle of therapy consisted of eight weekly treatments. Fifteen of 32 patients (47%) responded to chemotherapy, whereas 13 (41 %) had stable disease and four (12%) progressed on therapy. Of the 15 responding patients, 13 were completely resected after chemotherapy and two of them had a complete pathological response. Two clinically responding patients were found unresectable at operation because of peritoneal seeding. At a median follow-up from the start of treatment of 24 months (range 11-39 months), 10 of 13 resected patients are alive and eight are relapse free. Three patients died after 11, 12, and 14 months respectively. Toxicity was acceptable: side-effects consisted mainly of grade II National Cancer Institute common toxicity criteria (NCICTC) leucopenia and thrombocytopenia in ten patients. Neither treatment-related death nor surgical complications in patients undergoing surgery were observed. This weekly intensive regimen enabled resection in half of previously inoperable tumours with a moderate toxicity. It can be offered to patients with locally advanced unresectable gastric cancer to obtain curative resection.

Cisplatin-induced apoptosis in rat dorsal root ganglion neurons is associated with attempted entry into the cell cycle

Platinum compounds induce apoptosis in malignant cells and are used extensively in the treatment of cancer. Total dose is limited by development of a sensory neuropathy. We now demonstrate that when rats are administered cisplatin (2 mg/kg i.p. for 5 d), primary sensory neurons in the dorsal root ganglion die by apoptosis. This was reproduced by exposure of dorsal root ganglion neurons and PC12 cells to cisplatin (3 microg/ml) in vitro. Apoptosis was confirmed by electron microscopy, DNA laddering, and inhibition by the caspase inhibitor z-VAD.fmk (100 microM). Cell death in vitro was preceded by upregulation of cyclin D1, cdk4, and increased phosphorylation of retinoblastoma protein; all are indicators of cell cycle advancement. The level of p16(INK4a), an endogenous inhibitor of the cyclin D1/cdk4 complex decreased. Exposure of PC12 cells and dorsal root ganglion neurons to increased levels of nerve growth factor (100 ng/ ml) prevented both apoptosis and upregulation of the cell cycle markers. Cancer cells without nerve growth factor receptors (gp140TrkA) were not protected by the neurotrophin. This indicated that cisplatin may kill cancer cells and neurons by a similar mechanism. In postmitotic neurons, this involves an attempt to re-enter the cell cycle resulting in apoptosis which is specifically prevented by nerve growth factor.

Experimental cisplatin neuronopathy in rats and the effect of retinoic acid administration

Peripheral nervous system alterations were induced in adult rats by administration of cisplatin (CDDP) 2 mg/kg twice weekly for 4.5 weeks. Dorsal root ganglion neurons showed pathological changes. Morphometric determinations demonstrated a reduction in size of the somatic, nuclear and nucleolar area. The nucleoli were the most involved subcellular structures. Nerve conduction velocity and the tail-flick test for pain were both significantly altered in CDDP treated rats, whereas the rota-rod test for coordination revealed no changes in either treated or control rats. Analytical determinations demonstrated platinum accumulation in the DRG of CDDP treated rats. Spontaneous recovery, demonstrated by morphometric, electrophysiological, functional and analytical determinations, occurred after treatment discontinuation within about 7 weeks. A pilot study of the possible neuroprotective action of retinoic acid (RA) was also performed with this model of cisplatin neuronopathy. The rationale for using RA was based on its assumed antioxidant and neurotrophic effect. However, RA failed to prevent morphometric, electrophysiological, functional and analytical alterations induced by CDDP on DRG neurons. RA induced only a mild generalized protective effect.

A phase I study of paclitaxel and 5-fluorouracil in advanced gastric cancer

This is a phase I study to determine the maximum tolerated dose (MTD) and toxicity of a combination of paclitaxel and 5-Fluorouracil (5-FU) in advanced gastric cancer patients. The patients, refractory to the PELF regimen (5-FU, leucovorin, cisplatin, epidoxorubicin), received weekly 5-FU at the fixed dose of 500 mg/m2, and escalating doses of paclitaxel every 3 weeks with a starting dose of 150 mg/m2 given as in 3-h infusion. The dose was escalated by 25 mg/m2 every 3 patients. Fifteen patients entered the study. The upper paclitaxel dose (225 mg/m2) was given to 6 patients. Up to this dose, no severe toxicity (grade 3-4) was recorded. Apart from alopecia, grade 1-2 leukopenia occurred in 5 patients and grade 1-2 neurotoxicity in 2 patients. All patients were evaluable for response (at least 2 cycles): 2 patients achieved an objective response (200 and 225 mg/m2). In 6 patients, treatment resulted in notable relief from symptoms. Out-patient paclitaxel given over 3 h and 5-FU may be combined safely for the treatment of patients with advanced gastric cancer. The recommended doses for phase II study are paclitaxel 225 mg/m2 and 5-FU 500 mg/m2.

Peripheral neuropathy induced by combination chemotherapy of docetaxel and cisplatin

Docetaxel, a new semisynthetic taxoid that has demonstrated promising activity as an antineoplastic agent, was administered in combination with cisplatin to 63 patients in a dose-escalating study. As both drugs were known to be potentially neurotoxic, peripheral neurotoxicity was prospectively assessed in detail. Neuropathy was evaluated by clinical sum-score for signs and symptoms and by measurement of the vibration perception threshold (VPT). The severity of neuropathy was graded according to the National Cancer Institute's 'Common Toxicity Criteria'. The docetaxel-cisplatin combination chemotherapy induced a predominantly sensory neuropathy in 29 (53%) out of 55 evaluable patients. At cumulative doses of both cisplatin and docetaxel above 200 mg m(-2), 26 (74%) out of 35 patients developed a neuropathy which was mild in 15, moderate in ten and severe in one patient. Significant correlations were present between both the cumulative dose of docetaxel and cisplatin and the post-treatment sum-score of neuropathy (P < 0.01) as well as the post-treatment VPT (P < 0.01). The neurotoxic effects of this combination were more severe than either cisplatin or docetaxel as single agent at similar doses.

Comparative adverse effect profiles of platinum drugs

Since the discovery of the biologically active platinum complexes 30 years ago, 2 agents have become widely established in clinical oncology practice. Both cisplatin and carboplatin are platinum(II) complexes with 2 ammonia groups in the cis- position. However, they differ in their solubility, chemical reactivity, dichloride or alicyclic oxygenated leaving groups, pharmacokinetics and toxicology. Cisplatin causes severe renal tubular damage and reduces glomerular filtration, and requires concurrent saline hydration and mannitol diuresis to eliminate potentially lethal and unacceptable damage to the kidneys. Carboplatin, at conventional doses, causes no decrease in glomerular filtration and only minor transient elevations in urinary enzymes. Cisplatin is the most emetic cancer drug in common use, while nausea and vomiting associated with carboplatin are moderately severe. Serotonin release from enterochromaffin gut mucosal cells and stimulation of serotonin 5-HT3-receptors mediates acute emesis. Selective inhibitors of the 5-HT3-receptor protect against cisplatin- and carboplatin-induced nausea and vomiting. Peripheral neurotoxicity is the most dose-limiting problem associated with cisplatin. Loss of vibration sense, paraesthesia and sensory ataxia comes on after several treatment cycles. Carboplatin, however, is relatively free from peripheral neurotoxicity. Audiometry shows cisplatin-induced ototoxicity in 75 to 100% of patients, which may be associated with tinnitus and hearing loss. Ototoxicity is rare with conventional dose carboplatin therapy. Monitoring hearing with audiograms may identify early signs before significant impairment occurs. Cisplatin causes mild haematological toxicity to all 3 blood lineages. Haematological toxicity is dose-limiting for carboplatin, with thrombocytopenia being a greater problem than leucopenia. Although carboplatin is not toxic to the kidney, renal function markedly affects the severity of carboplatin-induced thrombocytopenia. The major clearance mechanism of cisplatin is irreversible binding in plasma and tissues, while carboplatin is cleared by glomerular filtration. Metabolism of cisplatin to aqua, amino acid and protein species is extensive, whereas carboplatin exists mainly as the free unchanged form. Strong relationships between carboplatin renal clearance, glomerular filtration rate, area under the plasma concentration-time curve (AUC) of filterable platinum and severity of thrombocytopenia have prompted dose adjustment according to renal function. New analogues such as JM216 offer the potential advantages of oral administration and few nonhaematological toxicities. Analogues based on the diaminocyclohexane ligand have encountered problematic neurotoxicity.