A phase I study of WR-2721 in combination with total body irradiation (TBI) in patients with refractory lymphoid malignancies

Amifostine in clinical oncology: current use and future applications

Amifostine (Ethyol), an inorganic thiophosphate, is a selective broad-spectrum cytoprotector of normal tissues that provides cytoprotection against ionizing radiation and chemotherapeutic agents, thus preserving the efficacy of radiotherapy and chemotherapy. This review summarizes the preclinical data and clinical experience with amifostine, and provides insight into future clinical directions. Amifostine, an inactive pro-drug, is transformed to an active thiol after dephosphorylation by alkaline phosphatase found in the normal endothelium. The absence of alkaline phosphatase in the tumoral endothelium and stromal components, and the hypovascularity and acidity of the tumor environment, may explain its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. Intravenous administration of amifostine 740-900 mg/m(2) before chemotherapy and 250-350 mg/m(2) before each radiotherapy fraction are widely used regimens. The US Food and Drug Administration has approved the use of amifostine as a cytoprotector for cisplatin chemotherapy and for radiation-induced xerostomia. Ongoing trials are being conducted to determine the efficacy of amifostine in reducing radiation-induced mucositis and other toxicities. Novel schedules and routes of administration are under investigation, and may further simplify the use of amifostine and considerably broaden its applications.

Alteration of radiation-induced hematotoxicity by amifostine

PURPOSE

To investigate whether amifostine can reduce radiation hematotoxicity.

PATIENTS AND METHODS

Seventy-three patients undergoing radiotherapy for squamous cell carcinoma of the head and neck at the university clinics of Freiburg, Heidelberg, and Erlangen were evaluated. All received 60 Gy (50-70 Gy) at 5 x 2 Gy fractions per week employing standard techniques. Thirty-five were randomized to receive 200 mg/m(2) amifostine i.v. 30 min before radiation; 38 served as control patients. Blood counts (total n = 501) were determined before, during, and while completing radiotherapy. Changes of leukocyte, platelet, and hemoglobin levels were determined and compared using the t test.

RESULTS

The blood hemoglobin level and the platelet count were not affected by irradiation, for either the amifostine-treated or control patients. Similarly, the leukocyte counts of amifostine-treated patients did not change during irradiation. However, control patients experienced a decrease in leukocyte count from 8.1 x 10(3)/mm(3) to 5.8 x 10(3)/mm(3) (difference: 2.3 x 10(3)/mm(3)). This seems to be line specific: Whereas amifostine does not affect lymphocyte count, a radiation-induced decrease of neutrophil granulocytes seems to be prevented.

CONCLUSION

Amifostine protects from radiation hematotoxicity, particularly affecting the granulocytopoiesis. These data confirm results from our former study.

A prospective randomized study of Chop versus Chop plus alpha-2B interferon in patients with intermediate and high grade non-Hodgkin's lymphoma: the International Oncology Study Group NHL1 Study

The addition of a brief alpha interferon regimen to each CHOP induction cycle, plus one year of alpha interferon thrice weekly maintenance therapy, has no early effect on response rates or survival in patients with Intermediate or High grade cell NHL.

BACKGROUND

The CHOP (Cyclophosphamide, Adriamycin. Vincristine, Prednisone) regimen is the most widely used first-line therapy for patients with Intermediate or High Grade (IG/HG) non-Hodgkin's lymphoma (NHL). Alpha 2b interferon (INF) enhances response rates and improves survival in low-grade NHL. The International Oncology Study Group (IOSG) conducted a prospective randomized study comparing CHOP alone or combined with INF in patients with IG/HG-NHL. The primary study aim was to compare the objective response rates in these patient cohorts.

PATIENTS AND METHODS

Patients with a confirmed diagnosis of measurable NHL of International Working Formulation (IWF) groups D to H histology were randomized to receive CHOP alone or CHOP with 5Mu INF s.c. for 5 days on days 22 to 26 of each 28 day cycle with INF 5 million units (Mu) given three times per week subcutaneously for 52 weeks in those patients who responded to CHOP plus INF.

RESULTS

The overall response rates were equivalent in both groups: CHOP alone (214 patients) 81% (complete 55%, partial 26%); CHOP plus INF (221 patients) 80% (complete 54%, partial 26%). At 36 months, the actuarial survival rate was equivalent in both groups.

CONCLUSIONS

There is no apparent early advantage in terms of response or survival conferred by adding the study INF regimen to CHOP therapy for patients with IG/HG-NHL.

Pilot trial of cytoprotection with amifostine given with high-dose chemotherapy and autologous peripheral blood stem cell transplantation

In an attempt to limit toxicities associated with dose-intensive therapy used for transplant regimens, we performed a pilot study using amifostine with high-dose busulfan (12 mg/kg), melphalan (100 mg/m2), and thiotepa (500 mg/m2) in 21 patients with a variety of malignancies. After 3 days of oral busulfan, amifostine was given at 910 mg/m2 IV for 10 minutes, preceding the infusion of each of 2 doses of melphalan and thiotepa given for 4 days. Antiemetic premedication for amifostine was given to all patients. The median patient age was 50 years (range: 32-65 years). Twenty-one patients received 82 separate amifostine infusions. One patient discontinued amifostine after the second dose because of severe nausea and emesis, and two infusions were temporarily held secondary to hypotension. Of these 82 cycles, there was a total of 37 episodes of nausea/vomiting, 28 episodes of sneezing, 11 episodes of flushing, and 1 episode of oral paresthesia. Systolic blood pressure and mean arterial pressure decreased by a mean of 8.4 mm Hg and 5.0 mm Hg, respectively. In general, the infusion was well tolerated. Patients were observed until discharge home (N = 15), until initiation of an additional tandem transplant procedure (N = 4), or until death (N = 2). All twenty-one patients experienced nonhematologic toxicities grade II or greater. Grade II toxicities included mucositis (N = 21), gastrointestinal (N = 3), skin (N = 1), and liver (N = 1), and grade III toxicities included liver (N = 1). Mucositis was also scored according to a detailed toxicity assessment. Mucositis did not appear to be improved with amifostine when compared with a control group of patients not receiving amifostine. Renal dysfunction after transplantation was decreased in the amifostine group, whereas there was no significant effect on posttransplant hepatic dysfunction. Although these data demonstrate the feasibility of delivering parenteral amifostine in conjunction with dose-intensive chemotherapy and autologous peripheral blood stem cell transplantation, there was no evidence of a significant reduction in nonmarrow toxicities.

Amifostine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential as a radioprotector and cytotoxic chemoprotector

Amifostine (WR-2721) was originally developed as a radioprotective agent. In animals, it protects normal tissues from the damaging effects of irradiation and, as shown in more recent studies, of several cytotoxic agents. Protection of tumours is generally reduced compared with that of normal tissues in animals, suggesting that amifostine may increase the therapeutic window of cytotoxic therapies. Clinical data concerning amifostine suggest that cytotoxic chemotherapy-induced haematological toxicity and cisplatin-induced neurotoxicity, nephrotoxicity and ototoxicity are decreased upon administration of amifostine prior to cytotoxic drugs. Similarly, amifostine reduces damage to normal tissues caused by radiotherapy. Available data show that this protection is achieved without adversely affecting tumour response or patient survival. In 1 large trial, the reduction in cyclophosphamide- and cisplatin-related toxicities manifested as a decrease in the incidence and severity of neutropenia-related fever and sepsis and in the number of patients with ovarian cancer who discontinue therapy before completion of treatment, thus improving the tolerability of this antineoplastic regimen. In addition, the incidences of cisplatin-induced nephro- and neurotoxicity were reduced. Increased doses of cytotoxic therapy have also been administered when amifostine was given prior to therapy, which may increase tumour response. The predominant adverse effect associated with amifostine are hypotension, nausea and vomiting, somnolence and sneezing. Thus, amifostine is likely to be a useful adjuvant to the treatment of patients with malignancy, particularly those receiving cyclophosphamide plus cisplatin. discontinued therapy before completion of treatment, thus improving the tolerability of this antineoplastic regimen. In addition, the incidences of cisplatin-induced.

Cardioprotective potency of the radical scavenger S-2-(3 aminopropylamino) ethylphosphorothioic acid in the post-ischaemic rat heart

S-2-(3 aminopropylamino) ethylphosphorothioic acid (WR-2721) shown to surpass radical scavenging thiols in their radioprotective efficacy in cancer-type diseases has been tested for its protective potential in the reperfused heart. We investigated the radical scavenger properties of the compound in a radical generating system in vitro as well as in isolated rat hearts subjected to 30 min ischaemia and 30 min reperfusion with the electron-paramagnetic resonance spin trap technique. The action on high-energy phosphates is observed by means of phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy while its influence on left ventricular systolic segmental length change (SSLC) during 60 min reperfusion following 60 min regional ischaemia was assessed with a fibreoptic system in anaesthetized open-chest rats. WR-2721 (0.1 mM) reduced the vascular concentration of radical adduct in isolated hearts by up to 78% (275 +/- 84% of pre-ischaemic baseline values vs 1260 +/- 413%, p < 0.05) between 5 and 12.5 min reperfusion. This was accompanied by a reduction of the left ventricular end diastolic pressure to pre-ischaemic values at 30 min of reperfusion (9 +/- 6 mmHg vs 42 +/- 8 mmHg in the absence of WR-2721, p < 0.02). An accelerated recovery of creatine phosphate levels (78 +/- 5% of pre-ischaemia values vs 41 +/- 5% within 60 min reperfusion: p < 0.05) was observed under similar conditions with NMR-spectroscopy, although the post-ischaemic tissue content of adenosine triphosphate was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)