Evaluation of uroprotective efficacy of amifostine against cyclophosphamide induced hemorrhagic cystitis.
The role of amifostine in the prevention of cyclophosphamide-induced hemorrhagic cystitis (HC) was evaluated in the rat model. Urinary bladders from control rats that received no drugs (group I) were compared with those from rats receiving cyclophosphamide alone at a dose of 150 mg/kg (group II), and two other groups receiving amifostine at 100 mg/kg (group III) and 200 mg/kg (group IV), 15 min prior to cyclophosphamide. Bladders were assessed macroscopically and histologically at 24 h and after 7 days. All the animals that received cyclophosphamide alone developed severe HC. On the basis of the scores of macroscopic and histologic changes, animals that received amifostine showed excellent uroprotection. Only 2/6 rats in group III and 1/6 rats in group IV developed mild HC at 24 h. None of the rats in either of these groups showed any evidence of HC at 7 days. It is concluded that amifostine protects the urothelium against cyclophosphamide-induced HC. (+info
The sulfhydryl containing compounds WR-2721 and glutathione as radio- and chemoprotective agents. A review, indications for use and prospects.
Radio- and chemotherapy for the treatment of malignancies are often associated with significant toxicity. One approach to reduce the toxicity is the concomitant treatment with chemoprotective agents. This article reviews two sulfhydryl compounds, namely the agent WR-2721 (amifostine), a compound recently registered for use in human in many countries, and the natural occurring compound glutathione (GSH). GSH is not registered as a chemoprotective agent. WR-2721 is an aminothiol prodrug and has to be converted to the active compound WR-1065 by membrane-bound alkaline phosphatase. WR-1065 and GSH both act as naturally occurring thiols. No protective effect on the tumour has been found when these compounds are administered intravenously. There is even in vitro evidence for an increased anti-tumour effect with mafosfamide after pretreatment with WR-2721, and in vivo after treatment with carboplatin and paclitaxel. Randomized clinical studies have shown that WR-2721 and GSH decrease cisplatin-induced nephrotoxicity and that WR-2721 reduces radiation radiotherapy-induced toxicity. Side-effects associated with WR-2721 are nausea, vomiting and hypotension, GSH has no side-effects. An exact role of WR-2721 and GSH as chemoprotectors is not yet completely clear. Future studies should examine the protective effect of these drugs on mucositis, cardiac toxicity, neuro- and ototoxicity, the development of secondary neoplasms and their effect on quality of life. (+info
Direct amifostine effect on renal tubule cells in rats.
Clinical trials indicate that amifostine offers protection against cisplatin-induced nephrotoxicity. It is unclear whether a direct pharmacological t on renal tubular cells is involved. We investigated the effect of amifostine pretreatment on the tubular apparatus and evaluated its nephroprotective potential. A total of 32 rats were treated by i.p. administration of 0.9% saline solution (group 1), 5 mg/kg cisplatin (group 2), 25 mg/kg amifostine (group 3), and 25 mg/kg amifostine followed by 5 mg/kg cisplatin (group 4) after 30 min. We recorded elevation of N-acetyl-beta-D-glucosaminidase (NAG) in 24 h pooled urine as a specific marker for tubular lesions, renal leakage of magnesium as an unspecific nephrotoxicity marker, and survival over a 10-day observation period. A significant (P < 0.002) increase in urinary NAG after treatment was documented only in cisplatin-treated group 2 [day 2 (mean+/-SE), 93+/-2.1 units/gram creatinine; day 4, 70.6+/-16 units/gram creatinine; normalization at day 8]. Treatment with amifostine before cisplatin administration resulted in a slight urinary NAG leakage (day 2, 2.8+/-1.8 units/gram creatinine; day 4, 13.8+/-13 units/gram creatinine; normalization at day 6). No increase in urinary enzyme levels was seen in the other groups, and there were no significant differences in urinary magnesium between all groups. Four of eight rats in the cisplatin-treated group and one of eight rats in the amifostine plus cisplatin-treated group died. (+info
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. (+info
Randomized phase II study of high-dose paclitaxel with or without amifostine in patients with metastatic breast cancer.
PURPOSE: To determine whether the neurotoxicity of paclitaxel 250 mg/m(2) given over 3 hours every 3 weeks could be reduced by pretreatment with amifostine 910 mg/m(2). Secondary objectives included comparing myelosuppression, myalgias, and response rates of the two groups. PATIENTS AND METHODS: Forty women with metastatic breast cancer were randomized to receive either paclitaxel alone (arm 1) or paclitaxel preceded by amifostine (arm 2). All were assessable for toxicity, and 37 were assessable for response. At baseline and after each cycle, all patients completed questionnaires for neurologic symptoms and had standardized neurologic examinations, including objective assessments of power and vibration sense. In addition, standard follow-up assessments for other toxicities and tumor response were undertaken. Changes from baseline after courses 1, 2, and 3 were assessed. The sample size was sufficient to detect a 50% improvement in the expected determination in sensory change. RESULTS: There were no differences observed in any of the measures of neurotoxicity. Other toxicity was similar in arms 1 and 2, including hair loss (95% v 90%), neurosensory changes (100% v 100%), fatigue/lethargy (85% v 90%), myalgia (95% v 90%), and grade 4 neutropenia (47% v 60%). Nausea, vomiting, dizziness, hypotension, and sneezing were more common in the amifostine arm. Response rates (22.2% v 36.8%) and paclitaxel pharmacokinetics were not significantly different. CONCLUSION: There was no protection from paclitaxel-related neurotoxicity or hematologic toxicity in this study. These results suggest that the mechanism of action of paclitaxel-related toxic effects is not amenable to the cytoprotective action of amifostine. (+info
American Society of Clinical Oncology clinical practice guidelines for the use of chemotherapy and radiotherapy protectants.
PURPOSE: Because toxicities associated with chemotherapy and radiotherapy can adversely affect short- and long-term patient quality of life, can limit the dose and duration of treatment, and may be life-threatening, specific agents designed to ameliorate or eliminate certain chemotherapy and radiotherapy toxicities have been developed. Variability in interpretation of the available data pertaining to the efficacy of the three United States Food and Drug Administration-approved agents that have potential chemotherapy- and radiotherapy-protectant activity-dexrazoxane, mesna, and amifostine-and questions about the role of these protectant agents in cancer care led to concern about the appropriate use of these agents. The American Society of Clinical Oncology sought to establish evidence-based, clinical practice guidelines for the use of dexrazoxane, mesna, and amifostine in patients who are not enrolled on clinical treatment trials. METHODS: A multidisciplinary Expert Panel reviewed the clinical data regarding the activity of dexrazoxane, mesna, and amifostine. A computerized literature search was performed using MEDLINE. In addition to reports collected by individual Panel members, all articles published in the English-speaking literature from June 1997 through December 1998 were collected for review by the Panel chairpersons, and appropriate articles were distributed to the entire Panel for review. Guidelines for use, levels of evidence, and grades of recommendation were reviewed and approved by the Panel. Outcomes considered in evaluating the benefit of a chemotherapy- or radiotherapy-protectant agent included amelioration of short- and long-term chemotherapy- or radiotherapy-related toxicities, risk of tumor protection by the agent, toxicity of the protectant agent itself, quality of life, and economic impact. To the extent that these data were available, the Panel placed the greatest value on lesser toxicity that did not carry a concomitant risk of tumor protection. RESULTS AND CONCLUSION: Mesna: (1) Mesna, dosed as detailed in these guidelines, is recommended to decrease the incidence of standard-dose ifosfamide-associated urothelial toxicity. (2) There is insufficient evidence on which to base a guideline for the use of mesna to prevent urothelial toxicity with ifosfamide doses that exceed 2.5 g/m(2)/d. (3) Either mesna or forced saline diuresis is recommended to decrease the incidence of urothelial toxicity associated with high-dose cyclophosphamide use in the stem-cell transplantation setting. Dexrazoxane: (1) The use of dexrazoxane is not routinely recommended for patients with metastatic breast cancer who receive initial doxorubicin-based chemotherapy. (2) The use of dexrazoxane may be considered for patients with metastatic breast cancer who have received a cumulative dosage of 300 mg/m(2) or greater of doxorubicin in the metastatic setting and who may benefit from continued doxorubicin-containing therapy. (3) The use of dexrazoxane in the adjuvant setting is not recommended outside of a clinical trial. (4) The use of dexrazoxane can be considered in adult patients who have received more than 300 mg/m(2) of doxorubicin-based therapy for tumors other than breast cancer, although caution should be used in settings in which doxorubicin-based therapy has been shown to improve survival because of concerns of tumor protection by dexrazoxane. (5) There is insufficient evidence to make a guideline for the use of dexrazoxane in the treatment of pediatric malignancies, with epirubicin-based regimens, or with high-dose anthracycline-containing regimens. Similarly, there is insufficient evidence on which to base a guideline for the use of dexrazoxane in patients with cardiac risk factors or underlying cardiac disease. (6) Patients receiving dexrazoxane should continue to be monitored for cardiac toxicity. Amifostine: (1) Amifostine may be considered for the reduction of nephrotoxicity in patients receiving cisplatin-based chemoth (+info
The potential of amifostine: from cytoprotectant to therapeutic agent.
BACKGROUND AND OBJECTIVE: Amifostine is an inorganic thiophosphate cytoprotective agent known chemically as ethanethiol, 2-[(3-aminopropyl)amino]dihydrogen phosphate. It is a pro-drug of free thiol that may act as a scavenger of free radicals generated in tissues exposed to cytotoxic drugs, and binds to reactive metabolites of such drugs. Amifostine was originally developed as a radioprotective agent in a classified nuclear warfare project. Following declassification of the project it was evaluated as a cytoprotective agent against toxicity of the alkylating drugs and cisplatin. In fact, pretreatment with amifostine was well tolerated and reduced the cumulative hematologic, renal and neurological toxicity associated with cisplatin, cyclophosphamide and vinblastine therapy of advanced and metastatic solid tumors. The objective of this review is to focus the importance of amifostine as a myeloprotective and cytoprotective drug during treatment with chemotherapeutics, presenting the most recent results, and to discuss the application of amifostine in the therapy of myelodysplastic syndromes. EVIDENCE AND INFORMATION SOURCES: The material analyzed in this study includes data published or under publication by the authors as full papers or clinical protocols. Articles and abstracts published in Journals covered by Medline constitute the other source of information. STATE OF THE ART AND PERSPECTIVES: Amifostine, formerly known as WR-2721, is an organic thiophosphate that was developed to protect normal tissues selectively against the toxicities of chemotherapy and radiation. Amifostine is a pro-drug that is dephosphorylated at the tissue site to its active metabolite by alkaline phosphatase. Differences in the alkaline phosphatase concentrations of normal versus tumor tissues can result in greater conversion of amifostine in normal tissues. Once inside the cell the free thiol provides an alternative target to DNA and RNA for the reactive molecules of alkylating or platinum agents and acts as a potent scavenger of the oxygen free radicals induced by ionizing radiation and some chemotherapies. Preclinical animal studies demonstrated that the administration of amifostine protected against a variety of chemotherapy-related toxicities including cisplatin-induced nephrotoxicity, cisplatin-induced neurotoxicity, cyclophosphamide- and bleomycin-induced pulmonary toxicity, and the cytotoxicities (including cardiotoxicity) induced by doxorubicin and related chemotherapeutic agents. Amifostine was shown to protect a variety of animal species from lethal doses of radiation. Studies in tumor-bearing animals demonstrated that the administration of amifostine results in cytoprotection without loss of antitumor activity. Multiple phase I studies were carried out with amifostine in combination with chemotherapy for various neoplasms. Appropriate doses of amifostine resulted to be 740-910 mg/m(2) in a single dose regimen, and 340 mg/m(2) in a multiple dose regimen. Amifostine afforded not only hematologic protection, but also other organ protection from cytotoxic agents such as nephrotoxicity, mucositis and peripheral neuropathy from cisplatin. Many studies have been performed to investigate cytoprotective efficacy of amifostine. In brief, amifostine gives hematologic protection from cyclophosphamide, carboplatin, mitomycin C, fotemustine and radiotherapy; renal and peripheral nerve protection from cisplatin; mucosa, skin, and salivary gland from radiotherapy. In phase I/II studies these properties have been confirmed, together with a generally good tolerability of the drug, hypotension being the most common side effect. It has been observed that amifostine possibly enhances the anti-tumor effect of carboplatin, nitrogen mustard, melphalan, and cisplatin combined with 5-FU or vinblastine. For all these characteristics, amifostine is at present broadly used as supportive treatment during chemotherapy, in lymphomas and solid tumors, and its spec (+info
Amifostine inhibits hematopoietic progenitor cell apoptosis by activating NF-kappaB/Rel transcription factors.
We investigated the involvement of NF-kappaB/Rel transcription factors that reportedly can inhibit apoptosis in various cell types in the antiapoptotic mechanism of the cytoprotectant amifostine. In the nontumorigenic murine myeloid progenitor 32D cells incubated with amifostine, we detected a reduction of the IkappaBalpha cytoplasmic levels by Western blotting and a raising of nuclear NF-kappaB/Rel complexes by electrophoretic mobility shift assay. Amifostine inhibited by more than 30% the growth factor deprivation-induced apoptosis, whereas its effect failed when we blocked the NF-kappaB/Rel activity with an NF-kappaB/Rel-binding phosphorothioate decoy oligodeoxynucleotide. In human cord blood CD34(+) cells, the NF-kappaB/Rel p65 subunit was detectable (using immunofluorescence analysis) mainly in the cytoplasm in the absence of amifostine, whereas its presence was appreciable in the nuclei of cells incubated with the cytoprotectant. In 4 CD34(+) samples incubated for 3 days in cytokine-deficient conditions, cell apoptosis was reduced by more than 30% in the presence of amifostine (or amifostine plus a control oligo); the effect of amifostine was abolished in cultures with the decoy oligo. These findings indicate that the inhibition of hematopoietic progenitor cell apoptosis by amifostine requires the induction of NF-kappaB/Rel factors and that the latter can therefore exert an antiapoptotic activity in the hematopoietic progenitor cell compartment. Furthermore, the identification of this specific mechanism underlying the survival-promoting activity of amifostine lends support to the possible use of this agent in apoptosis-related pathologies, such as myelodysplasias. (+info