Butirato de sodio como agente coadyuvante de la acción radioprotectora de la amifostina / Sodium butyrate as a coadyuvant agent of the radioprotecting action of amifostine / Butirato de sódio como agente coadjuvante da ação radioprotetora da amifostina

Entre los escasos radioprotectores en uso, la amifostina resulta eficaz para reducir la toxicidad aguda inducida por la radiación ionizante. Sin embargo, presenta efectos tóxicos importantes que impiden su uso repetido o en dosis altas. Es necesario entonces desarrollar radioprotectores menos tóxicos, por sí mismos o como coadyuvantes de la amifostina en dosis bajas. Se expusieron ratas Sprague-Dawley a una dosis de rayos X de 6 Gy (cuerpo entero). Se ensayó el butirato de sodio como mitigante luego de una dosis baja de amifostina previa a la irradiación. A distintos tiempos después de la irradiación se realizó el recuento de eritrocitos, leucocitos y la fórmula leucocitaria. Los efectos genotóxicos se evaluaron en leucocitos de sangre mediante el ensayo Cometa. Se realizaron también estudios de supervivencia a 60 días y la evaluación histológica del duodeno e intestino grueso. El efecto del tratamiento resultó moderadamente protector respecto de la recuperación de los valores normales de eritrocitos, leucocitos y la fórmula leucocitaria en los animales sobrevivientes en ambos sexos, así como de los epitelios intestinales y el ADN de los leucocitos. También aumentó significativamente la sobrevida a 60 días. La radioprotección con amifostina en una dosis baja seguida de una mitigación con butirato fue claramente significativa.

Among the few radioprotectors in use, amifostine is effective in reducing the acute toxicity induced by ionizing radiation. However, it has important toxic effects that prevent its repeated use or in high doses. It is necessary then to develop less toxic radioprotectors, by themselves or as adjuvants of amifostine in low doses. Sprague-Dawley rats were exposed to an X-ray dose of 6 Gy (whole body). Sodium butyrate was tested as a mitigant after a low dose of amifostine prior to irradiation. At different times after the irradiation, the erythrocytes, leukocytes and the leukocyte formula were counted. Genotoxic effects were evaluated in blood leukocytes by the Comet assay. Sixty-day survival studies and histological evaluation of the duodenum and large intestine were also performed. The effect of the treatment was moderately protective with respect to the recovery of the normal values of erythrocytes, leukocytes and the leukocyte formula in the surviving animals in both sexes as well as for the intestinal epithelia and leukocytes DNA. It also significantly increased the 60-day survival. The radioprotection with amifostine in a low dose followed by mitigation with butyrate was clearly significant.

Entre os poucos radioprotetores em uso, a amifostina é eficaz na redução da toxicidade aguda induzida pela radiação ionizante. No entanto, tem importantes efeitos tóxicos que impedem seu uso repetido ou em altas doses. É necessário, então, desenvolver radioprotetores menos tóxicos, isoladamente ou como coadjuvantes da amifostina em baixas doses. Ratos Sprague-Dawley foram expostos a uma dose de raios X de 6 Gy (corpo inteiro). O butirato de sódio foi testado como mitigante após uma dose baixa de amifostina antes da irradiação. Em diferentes momentos após a irradiação, os eritrócitos, leucócitos e a fórmula de leucócitos foram contados. Os efeitos genotóxicos foram avaliados em leucócitos de sangue pelo ensaio Cometa. Estudos de sobrevida de 60 dias e avaliação histológica do duodeno e do intestino grosso também foram realizados. O efeito do tratamento resultou moderadamente protetor em relação à recuperação de valores normais de eritrócitos, leucócitos e fórmula leucocitária nos animais sobreviventes em ambos os sexos, bem como protegeu epitélios intestinais e o DNA dos leucócitos. Também aumentou significativamente a sobrevida para 60 dias. A radioproteção com amifostina em baixa dose seguida de uma mitigação com butirato foi claramente significativa.

Efecto radioprotector del piruvato de etilo, solo o como coadyuvante de la amifostina / Radioprotective effect of ethyl pyruvate alone or as a coadyuvant of amifostine / Efeito radioprotetor do piruvato de etila, sozinho ou como um coadjuvante de amifostina

Entre los radioprotectores con uso clínico se destaca la amifostina (WR- 2721), eficaz pero con efectos secundarios que impiden su uso repetitivo. Es interés de los autores desarrollar radioprotectores menos tóxicos, por sí mismos o como coadyuvantes de amifostina. Ratas machos o hembras se expusieron a una dosis de rayos X de 2 Gy. Se ensayó el piruvato de etilo, solo o conjuntamente con amifostina. Cuarenta y ocho horas después de la exposición a la radiación, se realizó el recuento de eritrocitos, de leucocitos y la fórmula leucocitaria. Los efectos genotóxicos se evaluaron en leucocitos de sangre mediante el ensayo Cometa. Se realizaron también estudios de supervivencia a 60 días post-irradiación. En los animales irradiados disminuyeron los eritrocitos, y el recuento de leucocitos se redujo drásticamente respecto al control, presentando además una fórmula alterada. El tratamiento con piruvato de etilo resultó en una protección de los eritrocitos en ambos sexos. El daño genético disminuyó significativamente por el tratamiento con piruvato de etilo solo o combinado con amifostina, y en hembras se observó una mayor supervivencia solo con el tratamiento combinado. El piruvato de etilo mostró una acción radioprotectora significativa, que podría mejorarse aumentando la dosis o el tiempo de tratamiento, ya que tiene muy baja toxicidad.

Among the currently available radioprotectors, only amifostine (WR-2721) has shown in clinical trials to reduce radiation-induced toxicity. This compound is an efficient radioprotector but it exhibits some undesirable side effects which prevent its repetitive use. Efforts are directed to develop radioprotective agents with lower toxicity, with their own protective potential or suitable as coadyuvants of amifostine. The present study describes the results obtained by repetitive oral administration of ethyl pyruvate. Male or female rats were exposed to an X-ray dose of 2 Gy. Forty-eight hours after exposure to radiation, erythrocyte count, leukocyte and differential count were performed. Genotoxic effects were assessed in blood leukocytes by the Comet assay. Survival studies were also performed at 60 days post-irradiation. Eritrocyte and leukocyte were reduced in animals exposed to radiation compared to the control, also presenting an altered formula. Treatment with ethyl pyruvate resulted in a protection on erythrocytes of both sexes. Genetic damage was significantly decreased by ethyl pyruvate alone or combined with amifostine, and in females, higher survival was observed only with combined administration. Ethyl pyruvate showed a significant radioprotective action, which could be improved by increasing the dose or time of treatment because it has low toxicity.

Entre os radioprotetores com uso clínico destaca-se a amifostina (WR-2721) eficaz mas com efeitos secundários que impedem seu uso repetitivo. O interesse dos autores é desenvolver radioprotetores menos tóxicos, por si mesmos ou como coadjuvantes de amistofina. Ratos machos ou fêmeas foram expostos a doses de raios X de 2Gy. Ensaiou-se o piruvato de etila, só ou junto com amifostina. Quarenta e oito horas após a exposição à radiação foi realizada a contagem de eritrócitos, de leucócitos e da fórmula leucocitária. Efeitos genotóxicos foram avaliados em leucócitos do sangue pelo Ensaio Cometa. Estudos de sobrevivência foram também realizados a 60 dias pós-irradiação. Nos animais irradiados diminuíram os eritrócitos, e a contagem de leucócitos se reduziu drasticamente em comparação com o controle, apresentando também uma fórmula alterada. O tratamento com piruvato de etila resultou numa proteção dos eritrócitos em ambos os sexos. O dano genético diminuiu significativamente pelo tratamento com piruvato de etila sozinho ou combinado com amifostina, e nas fêmeas se observou maior sobrevivência só com o tratamento combinado. O piruvato de etila mostrou uma ação radioprotetora significativa, que poderia ser melhorada pelo aumento da dose ou do tempo de tratamento, visto que tem baixa toxicidade.

Improvement of the in vitro safety profile and cytoprotective efficacy of amifostine against chemotherapy by PEGylation strategy.

Amifostine, an organic thiophosphate prodrug, has been clinically utilized for selective protection of normal tissues with high expression of alkaline phosphatase from oxidative damage elicited by chemotherapy or radiotherapy. However, the patients receiving amifostine suffer from severe dose-dependent adverse effects. Strategies for improvement of the protective efficacy and toxicity profile of amifostine are urgently required. Here we constructed a PEGylated amifostine (PEG-amifostine) through conjugation of amifostine to the 4-arm PEG (5000 Da) by a mild one-step reaction. The relatively large PEG-amifostine molecules clustered into spherical nanoparticles, resulting in distinct hydrolysis properties, cell uptake profile and antioxidative activity compared with the free small molecules. PEGylation prolonged the hydrolysis time of amifostine, providing sustained transformation to its functional metabolites. PEG-amifostine could be internalized into cells and translocated to acidic organelles in a time-dependent manner. The intrinsic cytotoxicity of amifostine, which is related to the reductive reactivity of its metabolites and their ability to diffuse readily, was attenuated after PEGylation. This modification impeded the interaction between free sulfhydryls and functional biomolecules, providing PEG-amifostine with an improved safety profile in vitro. Moreover, PEG-amifostine showed higher efficiency in the elimination of reactive oxygen species and prevention of cisplatin-induced cytotoxicity compared with free amifostine. Overall, our study for the first time developed a PEGylated form of amifostine which significantly improved the efficacy and decreased the adverse effects of this antioxidant in vitro with great promise for clinical translation. In vivo study is urgently needed to confirm and redeem the cytoprotective effects of the PEG-amifostine in chemotherapy.

Ranking the Binding Energies of p53 Mutant Activators and Their ADMET Properties.

The guardian of the genome, p53, is the most mutated protein found in all cancer cells. Restoration of wild-type activity to mutant p53 offers promise to eradicate cancer cells using novel pharmacological agents. Several molecules have already been found to activate mutant p53. While the exact mechanism of action of these compounds has not been fully understood, a transiently open pocket has been identified in some mutants. In our study, we docked twelve known activators to p53 into the open pocket to further understand their mechanism of action and rank the best binders. In addition, we predicted the absorption, distribution, metabolism, excretion and toxicity properties of these compounds to assess their pharmaceutical usefulness. Our studies showed that alkylating ligands do not all bind at the same position, probably due to their varying sizes. In addition, we found that non-alkylating ligands are capable of binding at the same pocket and directly interacting with Cys124. The comparison of the different ligands demonstrates that stictic acid has a great potential as a p53 activator in terms of less adverse effects although it has poorer pharmacokinetic properties.

Effect of melatonin, ascorbic acid, and succinic acid on the cumulative toxic effect of repeated treatment with gammafos (amifostine).

Daily treatment of outbred albino mice with gammafos in radioprotective doses of 300 and 500 mg/kg for 4 days produced a cumulative toxic effect. This effect was not observed after decreasing the dose of gammafos to 100 mg/kg. Repeated peroral administration of melatonin and ascorbic acid in a dose of 200 mg/kg 30 min before treatment with gammafos reduced its cumulative toxic effect. Succinic acid in a dose of 100 mg/kg was ineffective under these conditions. The cumulative death time for 50% animals receiving gammafos alone or in combination with melatonin, ascorbic acid, and succinic acid was 3.08, 4.29, 4.06, and 2.97 days, respectively.

A randomized trial of amifostine as a cytoprotectant for patients receiving myeloablative therapy for allogeneic hematopoietic stem cell transplantation.

We initiated a randomized study of amifostine (the organic thiophosphate formerly known as WR-2721) given to patients during myeloablative conditioning therapy for allogeneic bone marrow transplantation. Amifostine was given at a dose of 1000 mg/day of conditioning and was well tolerated if attention was given to serum calcium levels, blood pressure and antiemetics. Since August 1998, 60 patients (30 on each arm) have completed the study. There was no significant difference in the days to neutrophil or platelet engraftment in either arm of the study. Significantly, the duration of grade I-IV mucositis was decreased in the group that received amifostine (P=0.02). Also grade III or IV infections (P=0.008), duration of antibiotic therapy (P=0.03) and duration of fever (P=0.04) were significantly reduced with amifostine. However, there were no differences in the incidence of grade III or IV mucositis, liver toxicity or renal toxicity. There were also no differences in early mortality, relapse and long-term survival. We conclude that amifostine, while reducing the duration of mucositis and infections (possibly through some preservation of gut mucosal integrity), has a modest effect in allogeneic bone marrow transplants given the multiplicity of factors influencing organ toxicity and survival in this setting.

WR-2721 (Amifostine) ameliorates cisplatin-induced hearing loss but causes neurotoxicity in hamsters: dose-dependent effects.

Chemoprotective agents reduce the toxic side effects of chemotherapy agents such as cisplatin. The conventional belief is that the chemoprotective agent WR-2721 (Amifostine), while protecting against most cisplatin-induced side effects, does not protect against cisplatin-induced ototoxicity (i.e., hearing loss). There is no knowledge, however, about the efficacy of high doses of WR-2721 (WR) in possibly protecting against cisplatin-induced ototoxicity. Thus, the dose-dependent effects of WR in possibly ameliorating cisplatin-induced ototoxicity were investigated. Hamsters were given a series of 5 cisplatin injections (3 mg/kg/injection once every other day, i.p.) either alone or in combination with 18, 40, 80, or 400 mg/kg/injection of the rescue agent WR ( n = 5 or 10/group). Other groups received either 80 mg/kg/injection WR alone ( n = 5) or were untreated ( n = 14). Ototoxicity was assessed by auditory brain stem responses (ABR). WR provided dose-dependent rescue from cisplatin's ototoxicity with no protection at the low dose of 18 mg/kg, moderate protection at 40 mg/kg, and nearly complete protection at 80 and 400 mg/kg. However, WR doses of 40 mg/kg or higher caused neurotoxicity as evidenced by prolongations in the ABR's interpeak latencies. Thus, high doses of WR provided the beneficial effect of protecting against cisplatin-induced ototoxicity, but had the harmful side effect of neurotoxicity. Previous failures to find chemoprotection from cisplatin-induced ototoxicity were likely due to the use of WR doses that were too small. The clinical implications of the beneficial and harmful effects of high doses of WR are discussed.

Phase I study for poor-prognosis lymphoma: augmentation of the "BEAM" regimen with escalating dose melphalan using amifostine cytoprotection and autologous hematopoietic stem cell transplantation--a preliminary report.

We and others have previously shown that the use of amifostine (Ethyol; MedImmune Inc, Gaithersburg, MD) can ameliorate certain regimen-related toxicities of high-dose melphalan (HD-MEL) in the autologous hematopoietic stem cell transplant setting. Our recent experience indicated that the maximum tolerated dose of HD-MEL plus autologous hematopoietic stem cell transplant could be increased from approximately 200 mg/m2 to at least 280 mg/m2 with amifostine. Although a dose-limiting toxicity was not clearly identified, atrial fibrillation was noted in several patients. Phase II trials using this regimen have been reported in lymphoma and myeloma. Nonetheless, it is unlikely that single agent therapy, regardless of dose, will be highly curative in advanced hematologic malignancy. Thus, we used amifostine to permit dose escalation of HD-MEL within the BEAM (BCNU/etoposide/arabinosylcytosine/HD-MEL) combination chemotherapy regimen before autologous hematopoietic stem cell transplant in selected patients with lymphoma. Patient entry at the starting dose (ie, HD-MEL 140 mg/m2) has been completed without the development of severe regimen-related toxicities. This trial is ongoing.

Variable cytotoxicity of amifostine in malignant and non-malignant cell lines.

Amifostine is the best known radioprotector and chemoprotector which has already been incorporated into general oncology practice. However, the data regarding its action at the cellular level remain unclear. The present study examined the effect of amifostine with and without ionizing radiation on the growth of malignant and non-malignant cell lines. Amifostine was found to have a remarkable cytotoxic effect on malignant epithelial cell lines but a modest cytotoxic effect on malignant melanoma and non-malignant cell lines. It demonstrated an additive effect with radiation therapy on the malignant cell line and a variable effect on the non-malignant cell line. Endothelial cells were not affected by amifostine, but the myoblast cells showed a synergistic effect of amifostine and radiation. These findings demonstrate that the cytotoxic as well as the radioprotective effect of amifostine are cell-specific. Thus, caution should be exercised in the use of amifostine as a radioprotector, and it should be tested for each model of disease.

Phase I clinical and pharmacologic study of weekly cisplatin and irinotecan combined with amifostine for refractory solid tumors.

PURPOSE: This Phase I study was designed primarily to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of irinotecan and cisplatin with and without amifostine in children with refractory solid tumors. PATIENTS AND METHODS: Cisplatin, at a fixed dose of 30 mg/m(2), and escalating doses of irinotecan (starting dose, 40 mg/m(2)) were administered weekly for four consecutive weeks, every 6 weeks. After the MTD of irinotecan plus cisplatin was determined, additional cohorts of patients were enrolled with amifostine (825 mg/m(2)) support. Leukocyte DNA-platinum adducts and pharmacokinetics of cisplatin and WR-1065 (amifostine-active metabolite) were also determined. RESULTS: Twenty-four patients received 43 courses of therapy. The MTD for irinotecan administered in combination with cisplatin (30 mg/m(2)) was 50 mg/m(2). The DLTs of this combination were neutropenia and thrombocytopenia. With the addition of amifostine, at an irinotecan dose of 65 mg/m(2) and cisplatin dose of 30 mg/m(2), the DLT was hypocalcemia. Although no objective responses were observed, six patients received at least three courses of therapy. The amounts of platinum adducts (mean +/- SD) were 10 +/- 20 molecules/10(6) nucleotides. The maximum plasma concentrations (C(max)) for free cisplatin and WR-1065 were 4.5 +/- 1.6 micro M and approximately 89 +/- 10 micro M, respectively. The half-life (t(1/2)) for free plasma cisplatin was 25.4 +/- 5.4 min. The initial t(1/2) for plasma WR-1065 was approximately 7 min and terminal t(1/2) approximately 24 min. CONCLUSION: The combination of cisplatin and irinotecan administered weekly for 4 weeks in children with refractory cancer is well tolerated. Amifostine offers some myeloprotection, likely permitting >/=30% dose escalation for irinotecan, when administered in a combination regimen with cisplatin. However, effective antiemetics and calcium supplementation are necessary with the use of amifostine. Further escalation of irinotecan dosing, using these precautions for amifostine administration, may be possible.

A pilot study on feasibility and efficacy of amifostine preceding high-dose melphalan with autologous stem cell support in myeloma patients.

To evaluate feasibility and potential efficacy of amifostine (AMI) in the prevention of toxicities associated with high-dose melphalan (MEL), ten myeloma patients received AMI 910 mg/m2 in 15 min infusion preceding MEL 200 mg/m2 followed by stem cell infusion (AMI group). Hematologic and extra-hematologic toxicities as well as the need for supportive care observed in the AMI group were compared with ten myeloma patients treated in an identical protocol but without AMI. Hypotension was the most important adverse event of AMI infusion. No differences were observed in the time of engraftment between the AMI group and the control group neither was there any difference in the need for supportive care. Oral mucositis grade >2 was observed in 30% of the patients in both groups. Diarrhea grade >2 occurred only in two AMI patients but in five control patients. AMI preceding high-dose MEL is feasible, although adverse events are observed in some patients. Whether AMI could reduce the gastrointestinal toxicity associated with high-dose MEL can be reliably assessed only in prospective randomized trials.

Amifostine reduces mucosal damage after high-dose melphalan conditioning and autologous peripheral blood progenitor cell transplantation for patients with multiple myeloma.

High-dose melphalan (HDM) has been adopted as standard therapy in the treatment of multiple myeloma. This treatment is associated with non-selective cytotoxicity, causing oral mucositis as the major non-hematological side-effect. Amifostine is a cytoprotector which prevents toxicity induced by anticancer therapy. We prospectively compared two groups of patients who either received (group A, n = 21) or did not receive (group B, n = 20) amifostine (740 mg/m(2)) before HDM (200 mg/m(2)) followed by autologous peripheral blood progenitor cell transplantation. The occurrence of severe oral mucositis was significantly decreased in group A in comparison to group B (33% vs 65%, P < 0.05). Six patients in group A required opioid analgesic therapy during a mean period of 4.8 days as compared to eight patients for 6.5 days in group B (P = NS). Delayed vomiting was less frequent in group A (43% vs 70%, P = 0.07) and significantly less severe in group A (grade 2-4) vomiting: two patients vs nine patients, P < 0.02). No difference was observed between the two groups in either hematological toxicity after HDM or in response rate. Grade I emesis was the only immediate side-effect observed after amifostine administration. We conclude that amifostine can reduce mucositis induced by HDM.

Prophylactic efficacy of amifostine and its analogues against sulphur mustard toxicity.

The successful implication of the chemical weapons convention stimulated research with a new vigour on the destruction of the stockpiled sulphur mustard (SM). A prophylactic agent for SM will be very useful for personnel engaged in the destruction of SM and during inspections by the Organisation for the Prohibition of Chemical Weapons. Due to simple method of preparation, SM can be used clandestinely during war or by terrorist groups. Inspite of research over several decades no satisfactory prophylactic or treatment regimen has evolved for SM. Amifostine an organophosphorothioate, originally developed as a radioprotector, and its analogues were evaluated as a prophylactic agent for SM. Three analogues by varying the chain length and substitution at the sulphur atom were synthesised and coded as DRDE-06, DRDE-07 and DRDE-08. LD(50) of amifostine and its analogues were estimated through intraperitoneal (i.p.) route. For the protection studies, amifostine and its analogues were administered i.p. in mice, 30 min before dermal (percutaneous) application of SM. The dose of the prophylactic agent was 0.2 LD(50) (i.p.) and that of SM was 152 mg/kg (undiluted) equal to 19-fold LD(50) of SM. Amifostine and one of its analogues, DRDE-07 gave significant protection. Further studies were carried out using amifostine and DRDE-07, and both of them significantly protected mice against SM (155 mg/kg, in PEG 300, equal to 19 LD(50)) when they were administered i.p. either 30 min before or simultaneously. LD(50) of amifostine and DRDE-07 were also estimated through the oral route (1049 or 1248 mg/kg, respectively). Prophylactically administered amifostine and DRDE-07 (0.2 LD(50), p.o.) significantly protected the mice against dermally applied SM (155 mg/kg, in PEG 300, equal to 19 LD(50)). The protection offered by DRDE-07 was better than that of amifostine by the oral route. DRDE-07 (0.2 LD(50), p.o.) also protected significantly with respect to the decrease in body weight and the depletion of GSH induced by SM. DNA damage induced by SM was also significantly reduced by amifostine and DRDE-07 (0.2 LD(50), p.o.). Further studies are in progress on the various pharmacological and toxicological properties of DRDE-07.

Amifostine in combination with erythropoietin and G-CSF promotes multilineage hematopoiesis in patients with myelodysplastic syndrome.

Ineffective hematopoiesis leading to profound cytopenias represents a major clinical problem in the management of patients with myelodysplastic syndrome (MDS). The aminothiol amifostine has shown to promote multilineage hematopoiesis both in vivo and in vitro in patients with MDS. We have treated 10 patients with 250 mg/m2 amifostine thrice weekly in combination with erythropoietin for 4 consecutive weeks followed by 2 weeks observation. Responding patients received the same 6 week schedule, while nonresponder received G-CSF in addition to erythropoietin and amifostine during the second treatment course. All patients experienced single or multilineage hematologic improvement, but only 2 reached transfusion independency. Moreover, response was durable only in a minority of patients and thus additional studies are warranted to further define the potential interaction of amifostine and growth factors.

Tolerability of the cytoprotective agent amifostine in elderly patients receiving chemotherapy: a comparative study.

In order to determine if age and comorbidity influence the tolerability of the cytoprotective agent amifostine, we compared side effects related to amifostine in patients > or = 70 years (group I) with patients < 70 years (group II). We evaluated 268 consecutive administrations of amifostine (119 in group I and 149 in group II, respectively), given i.v. at a dose of 740 mg/m(2) just before platinum-, taxol- or cyclophosphamide-based chemotherapy. Transient hypotension was the most common side effect occurring in association with amifostine. Decreases in systolic blood pressure > 20 mmHg were of similar frequency in both groups (27.1 versus 28.8% of amifostine infusions in group I and II, respectively). Hypotension did not result in medical sequelae in any of the patients. The amifostine infusion was interrupted 16 times in group I and 8 times in group II, respectively, mainly due to hypotension, but could be restarted after a few minutes in all patients except for three cases in group I. Patients in group II more often suffered from nausea/vomiting than in group II (20.8 versus 10.0% in group I). Other subjective symptoms (e.g. warmed, flushed sensation, sneezing, metallic taste, mouth dryness, dizziness and sleepiness) and hypocalcemia occurred with a similar frequency in both groups. Adverse effects associated with amifostine were not observed more frequently in elderly patients than in younger ones, although more elderly patients had a comorbidity than the younger ones.

A randomized phase II study of amifostine used as stem cell protectant in non-hodgkin lymphoma patients receiving cisplatin-based salvage chemotherapy prior to stem cell transplant.

Stem cell mobilization may be inadequate in many lymphoma patients in need for autologous stem cell transplant (SCT). In this study, we sought to evaluate a potential role of amifostine as a stem cell chemoprotective agent in lymphoma patients receiving DHAP chemotherapy in preparation for high-dose chemotherapy (HDC) and stem cell transplant (SCT). In the beginning of the DHAP course, patients were randomized 1:1 to receive amifostine at 740 mg/m(2). Stem cells were mobilized with GCSF after the last cycle of DHAP. Stem cell collection started upon ANC recovery over 1000/mm(3). Standard 10 lt. apheresis daily with a goal of a minimum of 2 x 10(6) stem cells/kg were performed. Twenty-one patients have been enrolled; 10 received amifostine pretreatment (age, 20-64) and 11 were randomized to the control arm (age, 18-63). Prior chemotherapy was balanced in the two groups. The median number of DHAP treatments for each group was 2. Amifostine was well tolerated and was associated with higher stem cell collection. Toxicity and time to engraftment were comparable between the two groups. Our preliminary results may suggest a role of amifostine in protecting stem cells during salvage chemotherapy, thus facilitating stem cell collection.

Amifostine (WR-2721), a cytoprotective agent during high-dose cyclophosphamide treatment of non-Hodgkin's lymphomas: a phase II study

Clinical trials indicate that amifostine may confer protection on various normal tissues without attenuating anti-tumor response. When administered prior to chemotherapy or radiotherapy, it may provide a broad spectrum of cytoprotection including against alkylating drugs. The mechanism of protection resides in the metabolism at normal tissue site by membrane-bound alkaline phosphatase. Toxicity of this drug is moderate with hypotension, nausea and vomiting, and hypocalcemia being observed. We report a phase II study using amifostine as a protective drug against high-dose cyclophosphamide (HDCY) (7 g/m2), used to mobilize peripheral blood progenitor cells (PBPC) and to reduce tumor burden. We enrolled 29 patients, 22 (75.9 percent) affected by aggressive and 7 (24.1 percent) by indolent non-Hodgkin's lymphoma (NHL), who were submitted to 58 infusions of amifostine and compared them with a historical group (33 patients) affected by aggressive NHL and treated with VACOP-B followed by HDCY. The most important results in favor of amifostine were the reduction of intensity of cardiac, pulmonary and hepatic toxicity, and a significant reduction of frequency and severity of mucositis (P = 0.04). None of the 29 patients died in the protected group, while in the historical group 2/33 patients died because of cardiac or pulmonary toxicity and 2 patients stopped therapy due to toxicity. Amifostine did not prevent the aplastic phase following HDCY. PBPC collection and hematological recovery were adequate in both groups. The number of CFU-GM (colony-forming units-granulocyte/macrophage) colonies and mononuclear cells in the apheresis products was significantly higher in the amifostine group (P = 0.02 and 0.01, respectively). Side effects were mild and easily controlled. We conclude that amifostine protection should be useful in HDCY to protect normal tissues, with acceptable side effects.

Amifostine in the treatment of low-risk myelodysplastic syndromes.

BACKGROUND AND OBJECTIVE: The phosphorylated aminothiol agent amifostine (Ethyol) protects bone marrow and other tissues from toxicity due to ionizing radiation and antineoplastic drugs, and stimulates progenitors from normal and myelodysplastic bone marrow. Contrasting results have been published so far on the effectiveness of amifostine in correcting cytopenia in patients with myelodysplastic syndromes (MDS). DESIGN AND METHODS: In a pilot phase II study we treated 26 patients with low risk MDS (13 RA, 2 RARS, 2 CMML, 9 RAEB with blasts < 10%) with amifostine (200 mg/m(2 )x 3/week for 4 weeks). RESULTS: Hemoglobin concentration, reticulocyte, neutrophil and platelet counts increased respectively in 6 (23%), 11 (42%), 13 (50%) and 9 (34%) of patients. Red cell transfusions were reduced (> 50%) in 4/26 patients and abolished in 1/26. Unexpectedly a significant decrease in soluble transferrin receptor level at week 4 of therapy, compared to the basal level (p<0.04), was observed in the whole population of patients. INTERPRETATION AND CONCLUSIONS: Amifostine can ameliorate cytopenia in some patients with MDS, with few and mild side effects. Neutropenia is more likely to be corrected than anemia or thrombocytopenia. Mechanisms underlying this biological effect remain to be clarified.

Amifostine cytotoxicity and induction of apoptosis in a human myelodysplastic cell line.

Amifostine (AMF), a phosphorylated aminothiol, has been used to treat myelodysplastic syndrome (MDS), where it produces a stimulatory effect on hematopoiesis in bone marrow. To determine if AMF also produced a direct effect on human MDS cells, we planned a study to evaluate the effect of a continuous exposure to AMF on a human MDS cell line. AMF was shown to have a growth-inhibitory effect on MDS cells, with an IC(50) of 14 microM after a 5 day exposure. Cell cycle analysis revealed that a 5 day exposure to 20 microM AMF increased the percentage of cells in G0/G1 and this was accompanied by a decrease in the percentage of cells in S phase. Cytoflorometric and agarose-gel electrophoretic analysis revealed that this effect correlated with cell membrane alterations and DNA fragmentation consistent with an induction of apoptosis without affecting the expression of p53 protein or inducing any lymphoid or myeloid differentiation in the MDS cell line. We conclude that the continuous exposure of a human MDS cell line to AMF is cytotoxic and associated with an induction of apoptosis independent of alterations in p53 expression.

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