Experimental chemotherapy-induced skin necrosis in swine. Mechanistic studies of anthracycline antibiotic toxicity and protection with a radical dimer compound.

The reactivity of antitumor anthracycline and mitomycin C antibiotics with the oxomorpholinyl radical dimers, bi(3,5,5-trimethyl-2-oxomorpholin-3-yl) (TM3) and bi(3,5-dimethyl-5-hydroxymethyl-2-oxomorpholin-3-yl) (DHM3), was studied in vitro. The oxomorpholinyl radical reduced daunorubicin to a quinone methide intermediate that reacted with solvent to form 7-deoxydaunorubicinone. The solvolysis reaction followed first order kinetics, and the reactivity rate constants (k2) measured for seven anthracycline analogues ranged from 2 X 10(-2) s-1 to 8.0 X 10(-4) s-1. The chemical reactivity of each anthracycline quinone methide correlated with the total skin toxicity caused by the respective parent anthracycline following injection into swine skin. Microscopic examination of experimental lesions in swine skin resemble those observed in humans after inadvertant chemotherapy extravasation. Hydrocortisone sodium succinate was not effective for the treatment of doxorubicin-induced skin necrosis, whereas DHM3 was effective for the treatment of skin necrosis caused by all seven anthracyclines and by the quinone containing antibiotic, mitomycin C.

Anthracycline photoaffinity labeling of a mitochondrial polypeptide in P388 murine leukemic cell lines.

N-(p-Azido[3,5-3H]benzoyl)daunorubicin ([3H]NABD), a radioactive photoactive anthracycline analogue, was used to photoaffinity label anthracycline binding polypeptides in P388 murine leukemic cell lines. Whole cell homogenates were mixed with 6 X 10(-8) M [3H]NABD, exposed to ultraviolet light, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for radiolabel incorporation. Autoradiofluorography showed incorporation of radioactivity into a Mr 18,000 component independent of polypeptides prominently stained with Coomassie blue. Photolabeling of subcellular fractions showed predominant mitochondrial localization of the Mr 18,000 radiolabel. The protein composition of the photolabeled constituents was confirmed by treatment with proteinase K, DNase and RNase, or by lipid extraction with organic solvent. [3H]NABD photolabeling of homogenates from anthracycline sensitive and resistant cells resulted in Mr 18,000 radiolabel incorporation of 3,966 +/- 355 and 6,487 +/- 533 dpm per 50 micrograms cellular protein for anthracycline sensitive and resistant cells, respectively (P less than 0.005). These studies characterize the photoaffinity labeling of a low molecular weight mitochondrial polypeptide using a photoactive anthracycline analogue. The role for this polypeptide as a mediator of anthracycline activity remains to be determined.

Radical dimer rescue of toxicity and improved therapeutic index of adriamycin in tumor-bearing mice.

The product of adriamycin (ADR) reductive glycosidic cleavage is the pharmacologically inactive 7-deoxyadriamycin aglycone. Bi(3,5-dimethyl-5-hydroxymethyl-2-oxomorpholin-3-yl) (DHM3) is a radical dimer which reacts with ADR in vitro to produce this aglycone. We utilized DHM3 to prevent ADR toxicity in mice. CD2F1 male mice were given a single dose of ADR, 25 mg/kg i.p., which was acutely lethal as indicated by a median survival time of 7 days. DHM3 administered as a single i.p. dose of 50 mg/kg 15 or 30 min following ADR provided significant protection with median survival times greater than 9 wk. Mice bearing ascitic L1210 leukemic cells were given ADR, 0, 6.6, 15, or 25 mg/kg i.p. 1 day following inoculation of tumor. DHM3 administered as a single 50 mg/kg i.p. dose 20 min after ADR had no significant effect on ADR efficacy at the lower dose range (% treated versus control = 171 and 285 for 6.6 and 15.0 mg/kg, respectively). Less than 15% of the animals in these treatment groups were long-term survivors. However, following high doses of ADR (25 mg/kg), DHM3 protected mice from ADR lethality and over 70% of animals were long-term survivors. The determination of parent ADR and ADR aglycone content in several tissues indicated that the concentration of ADR was reduced in those animals that received DHM3 15 min after ADR. Correspondingly an increase in ADR aglycone concentration in each tissue resulted from DHM3 treatment. DHM3 represents a novel class of compounds that can ameliorate ADR toxicity and has potential use as a rescue agent.

The tyrosine kinase inhibitor ZD1839 ("Iressa") inhibits HER2-driven signaling and suppresses the growth of HER2-overexpressing tumor cells.

The epidermal growth factor receptor (EGFR) is commonly overexpressed in many human tumors and provides a new target for anticancer drug development. ZD1839 ("Iressa"), a quinazoline tyrosine kinase inhibitor selective for the EGFR, has shown good activity in preclinical studies and in the early phase of clinical trials. However, because it remains unclear which tumor types are the best targets for treatment with this agent, the molecular characteristics that correlate with tumor sensitivity to ZD1839 have been studied. In a panel of human breast cancer and other epithelial tumor cell lines, HER2-overexpressing tumors were particularly sensitive to ZD1839. Growth inhibition of these tumor cell lines was associated with the dephosphorylation of EGFR, HER2, and HER3, accompanied by the loss of association of HER3 with phosphatidylinositol 3-kinase, and down-regulation of Akt activity. These studies suggest that HER2-overexpressing tumors are particularly susceptible to the inhibition of HER family tyrosine kinase signaling and suggest novel strategies to treat these particularly aggressive tumors.

Doxorubicin-induced skin necrosis in the swine model: protection with a novel radical dimer.

The treatment of doxorubicin (DOX) extravasation tissue injury is poorly defined. A swine model has been developed to study DOX skin toxicity and potential pharmacologic antidotes. Intradermal injections of DOX in miniature female weanling swine produced predictable and dose-dependent ulcerations that closely resemble lesions observed in humans following extravasation of DOX. The ulcers reached maximal size at 3 weeks following DOX administration and were completely healed by 7 weeks. Bi(3,5-dimethyl-5-hydroxymethyl-2-oxomorpholin-3-yl) (DHM3) is a radical dimer that can react with DOX in vitro to produce deoxydoxorubicin aglycone, an inactive anthracycline metabolite. When DHM3 was administered into the same intradermal injection site 15 minutes after DOX, the maximum ulcer size was reduced 80%, and the healing time was reduced to 5 weeks. The protection from toxicity was highly dependent on the time interval between DOX and DHM3 injections, with no protection noted after a 60-minute interval. Our data verify the swine model as a useful tool to study DOX-induced extravasation injury. Furthermore, DHM3 is an effective antidote for DOX-induced skin necrosis and has potential for clinical use.

Dose-response study of alendronate sodium for the treatment of cancer-associated hypercalcemia.

PURPOSE: A randomized, double-blind, dose-ranging study of single-dose intravenous (IV) therapy with alendronate sodium (aminohydroxybutylidene bisphosphonate) was performed in patients with cancer-associated hypercalcemia. PATIENTS AND METHODS: Patients with hypercalcemia who had not received antitumor therapy in the preceding 7 days were treated with 48 hours of IV hydration. Patients with persistent hypercalcemia (albumin-corrected serum calcium concentration [CSCC] > or = 11.5 mg/dL) were randomly assigned to receive 2.5, 5, 10, or 15 mg of alendronate infused over 2 hours, or 10 mg of alendronate infused over 24 hours. Fifty-nine patients were treated and 50 patients were assessable for the dose-response relationship. RESULTS: Normalization of CSCC (< or = 10.5 mg/dL) was achieved in 22%, 82%, 75%, and 90% of assessable patients in the 2.5-, 5-, 10- (2- and 24-hour groups pooled), and 15-mg dose groups, respectively, within 8 days of therapy. Doses > or = 5 mg were significantly superior to the 2.5-mg dose level (P < .05). There was no significant difference in the minimum CSCC achieved between the 2- and 24-hour infusions of the 10-mg dose. Based on an intent-to-treat analysis of all randomized patients, the overall complete response rate was 74% for dose levels greater than 2.5 mg. For assessable patients who responded to > or = 5 mg of alendronate, the estimated median duration of normocalcemia was 10 days (range, 1 to 25). The estimated median time to relapse (CSCC > 11.5 mg/dL) was 15 days from initial treatment and 12 days from initial response, respectively. Adverse events included a transient febrile response in 34% of patients and eight episodes of reversible elevations in serum transaminase levels among treated patients. CONCLUSION: While a statistically significant dose-response relationship was not clearly evident at doses greater than 5 mg, single doses of > or = 5 mg alendronate sodium effectively lowered serum calcium concentrations and were well tolerated in the treatment of cancer-associated hypercalcemia.

Neuropeptide Y expression distinguishes malignant from benign pheochromocytoma.

No reliable gross or microscopic features distinguish benign from malignant pheochromocytomas. The diagnosis of malignant pheochromocytoma is based solely on the presence of regional or distant metastases. This study evaluated the expression of neuropeptide Y messenger RNA (mRNA) in nine benign and 11 malignant pheochromocytomas and has found that neuropeptide Y mRNA was expressed in all nine benign tumors but in only four of 11 malignant tumors (P = .0084). These data suggest that the determination of neuropeptide Y expression in the evaluation of patients with pheochromocytoma may have prognostic significance.

Phase I safety, pharmacokinetic, and pharmacodynamic trial of ZD1839, a selective oral epidermal growth factor receptor tyrosine kinase inhibitor, in patients with five selected solid tumor types.

PURPOSE: To establish the safety and tolerability of ZD1839 (Iressa), a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, and to explore its pharmacokinetic and pharmacodynamic effects in patients with selected solid tumor types. PATIENTS AND METHODS: This was a phase I dose-escalating trial of oral ZD1839 150 mg/d to a maximum of 1,000 mg/d given once daily for at least 28 days. Patients with either advanced non-small-cell lung, ovarian, head and neck, prostate, or colorectal cancer were recruited. RESULTS: Eighty-eight patients received ZD1839 (150 to 1,000 mg/d). At 1,000 mg/d, five of 12 patients experienced dose-limiting toxicity (grade 3 diarrhea [four patients] and grade 3 somnolence [one patient]). The most frequent drug-related adverse events (AEs) were acne-like rash (64%) and diarrhea (47%), which were generally mild (grade 1/2) and reversible on cessation of treatment. No change in ZD1839 safety profile was observed with prolonged administration. Pharmacokinetic analysis showed steady-state exposure to ZD1839 in 98% of patients by day 7. Nineteen patients had stable disease and received ZD1839 for >or= 3 months; seven of these patients remained on study drug for >or= 6 months. Serial skin biopsies taken before treatment and at approximately day 28 revealed changes indicative of inhibition of the EGFR signaling pathway. CONCLUSION: ZD1839 was generally well tolerated, with manageable and reversible AEs at doses up to 600 mg/d and dose-limiting toxicity observed at 1,000 mg/d. ZD1839 treatment resulted in clinically meaningful disease stabilization across a range of tumor types and doses. Pharmacodynamic changes in skin confirmed inhibition of EGFR signaling, which was predicted from the mode of action of ZD1839.

Fatal pulmonary hemorrhage due to nitrofurantoin.

Acute and chronic pleuropneumonic reactions as well as rare fatalities following nitrofurantoin exposure have been reported. A case of fatal fulminant hemorrhagic pneumonitis following nitrofurantoin exposure is reported here. Recent experimental evidence suggests that a toxic mechanism may be responsible for the observed reaction.

Treatment of malignant pheochromocytoma with combination chemotherapy.

Three patients with rapidly progressive, disseminated malignant pheochromocytoma were treated with a combination chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and dacarbazine in repeated 21- to 28-day cycles. All three patients had a marked decrease in blood pressure and an improvement in performance status within the first few cycles of treatment. At a follow-up of 6 to 13 months all patients continue to receive chemotherapy with further regression of tumor in two and stable disease in one. Their blood pressure is normal with minimal or no antiadrenergic therapy. Therapy has been well tolerated; moderate reversible granulocytopenia, neurotoxicity, and one episode of pneumonitis have been the major toxicities encountered. Thus, combination chemotherapy appears to be effective for symptomatic malignant pheochromocytoma.

ZD1839 ('Iressa') as an anticancer agent.

ZD1839 ('Iressa') is an orally active, selective epidermal growth factor receptor-tyrosine kinase inhibitor which blocks signal transduction pathways implicated in the proliferation and survival of cancer cells and other host-dependent processes promoting cancer growth. In preclinical studies, ZD1839 produced reversible growth inhibition and growth delay in a wide range of tumour cell lines and human tumour xenografts. Moreover, this activity was enhanced when ZD1839 was coadministered with cytotoxic agents. Preliminary results from phase I trials in patients with advanced disease and a wide variety of tumour types suggest that ZD1839 has an acceptable tolerability profile and promising clinical efficacy, particularly in non-small cell lung cancer (NSCLC). ZD1839 is currently in phase III clinical development for the treatment of advanced NSCLC. In addition, further trials are ongoing or planned in a number of other tumour types.

Cellular pharmacology and antitumor activity of N-(p-azidobenzoyl)-daunorubicin, a photoactive anthracycline analogue.

We have previously utilized N-(p-azidobenzoyl)daunorubicin (NABD), a photoactive analogue of daunorubicin (DNR), to identify unique anthracycline-binding polypeptides in rodent tissues and in tumor cells. Using cultured P388 tumor cells, we have now compared the cellular pharmacology and antitumor activity of NABD with that of DNR. Although rapidly accumulated by cells, the intracellular concentration of NABD was less than 20% that of DNR at steady-state levels. The cellular uptake of both drugs by P388 cells was dependent on extracellular drug concentration in the medium and on temperature. The rapid efflux of NABD and DNR from P388 cells in drug-free medium was reduced at lowered temperature (0 degrees C). Cytofluorescence microscopy demonstrated that NABD was predominantly localized in the cytoplasm, in contrast to the nuclear localization of DNR. NABD produced dose-dependent inhibition of [3H]thymidine (IC50 = 10.0 microM) and [3H]uridine (IC50 = 1.60 microM) incorporation in P388 cells to a lesser degree than DNR ([3H]thymidine, IC50 = 0.15 microM and [3H]uridine, IC50 = 0.70 microM). Continuous exposure to NABD inhibited P388 cell proliferation with an IC50 of 0.27 microM, compared with an IC50 of 0.017 microM for DNR. NABD is a pharmacologically active, photoactive analogue of DNR, which possesses properties different from those of the parent drug but similar to those of other anthracycline analogues. Photoaffinity labeling studies with NABD may identify important cytoplasmic constituents which interact with this type of anthracycline and perhaps with the anthracycline antibiotics in general.

Anthracycline assay by high-pressure liquid chromatography.

A general method of analysis of anthracycline concentrations was developed. Drug is extracted from plasma with organic solvent and separated from metabolites by high-pressure liquid chromatography on an aminocyanosilica column. Detection and quantitation are by the endogenous fluorescence of compounds having an intact tetracyclic ring structure. Limits of sensitivity are 5, 1, and 5 ng/ml of plasma for doxorubicin, carubicin, and marcellomycin, respectively. The assay can be used for studying the aldo-keto reductase and reductive glycosidase reactions with anthracyclines as the substrates and for the evaluation of the clinical pharmacology or pharmacodynamics of various doxorubicin analogs.

New bisphosphonates in the treatment of bone metastases.

Normal skeletal integrity is maintained by physiological bone turnover through a coupled process of bone resorption, mediated by osteoclasts, followed by new bone formation, mediated by osteoblasts. Major features of the pathogenesis of cancer-associated skeletal destruction are enhanced osteoclast-mediated bone resorption and disruption of normal bone formation. In this article, the literature on the pathogenesis and clinical manifestations of metastatic bone disease is discussed. Animal and clinical trials investigating novel bone targeted agents, emphasizing the bisphosphonates, are critically assessed. The most frequent clinical manifestations of bone metastases are pain, fracture, immobility, spinal cord compression, and hypercalcemia. New treatments under study for patients with bone metastases include agents specifically targeted to the skeleton such as bone-seeking radioisotopes and bisphosphonates. Studies in animal models of metastatic bone disease show that these bisphosphonates are able to inhibit tumor-induced osteolysis and are potentially useful in this condition. Bisphosphonates have been investigated in several clinical trials of patients with skeletal metastases from breast cancer, prostate cancer, and multiple myeloma. Overall, the studies investigating bone targeted radioisotopes or bisphosphonates for the treatment of morbidity due to skeletal metastases have been inconclusive. An improved understanding of the pathogenesis of metastatic bone disease and preclinical studies with bisphosphonates suggest that these agents may have a role in the treatment of this disorder. Additional trials of new generation bisphosphonates, employing a rigorously controlled, randomized study design with adequate numbers of subjects, are needed to demonstrate the safety and efficacy of this class of agents in this setting.

Brain metastasis from esophageal carcinoma.

Metastatic esophageal carcinoma to the brain is a rare occurrence that may account for abnormal neurological findings.

Rat heart anthracycline-binding polypeptides identified by photoaffinity labeling.

A radioactive, photoactive anthracycline analogue, N-(p-azido-[3,5-3H]benzoyl)-daunorubicin (3H-NAB-daunorubicin), was synthesized and characterized by UV-visible absorption and infrared analyses. 3H-NAB-daunorubicin photoaffinity labeling of rat heart homogenates resulted in the identification of two prominently radiolabeled anthracycline-binding polypeptides of 18.3 and 31.2 kDa. Photoaffinity labeling with photoactive doxorubicin (Adriamycin), carminomycin, and nonanthracycline model compounds resulted in a clear structural dependence for binding to the 18.3-and 31.2-kDa species. In the presence of daunorubicin or N-substituted daunorubicin analogues, 3H-NAB-daunorubicin photolabeling of the 18.3-kDa polypeptide was inhibited. Photolabeling was dependent on time of UV light exposure and protein concentration and was unaffected by the presence of nitrene scavengers. The 18.3-kDa polypeptide photolabeling was saturable and reversed by greater than 90% in the presence of a 16-fold molar excess of nonradioactive analogue. Photolabeling of heart subcellular fractions demonstrates that both the 18.3- and 31.2-kDa polypeptides were localized to the inner mitochondrial membrane. Since the anthracyclines are known to have several effects on heart mitochondrial function, the identification of specific polypeptide acceptors using photoactive anthracycline analogues may elucidate biochemical mechanisms of anthracycline cellular activity.

Treatment of advanced medullary thyroid carcinoma with a combination of cyclophosphamide, vincristine, and dacarbazine.

BACKGROUND: Medullary thyroid carcinoma (MTC) is a neoplasm of the parafollicular C cells of the thyroid gland, which belongs to the diffuse neuroendocrine system. This cancer usually behaves in a relatively indolent manner for most patients. However, approximately 20% of patients have a more aggressive course that requires effective management. There are few reported clinical trials of chemotherapy for MTC. From the literature, the most active agent appears to be doxorubicin, with response rates of 30% reported. On the basis of the activity of cyclophosphamide, vincristine, and dacarbazine (CVD) in other advanced neuroendocrine neoplasms, the authors tested the combination in patients with advanced MTC. METHODS: Seven patients with advanced MTC were treated with cyclophosphamide (750 mg/m2), vincristine (1.4 mg/m2), and dacarbazine (600 mg/m2 daily for 2 days in each cycle) every 3 weeks. Assessments of measurable tumor and serum calcitonin and carcinoembryonic antigen were made before treatment and followed up until progressive disease was documented. RESULTS: Two patients had partial tumor and biochemical responses for a duration of 14 and 29 months, respectively. One patient had a partial biochemical response and stable tumor measurements for 9 months, and another patient had stable tumor size and markers for 14 months. Three patients had progressive disease. Diarrhea and flushing improved in two patients who had partial biochemical responses. CONCLUSION: Our experience suggests that CVD chemotherapy has moderate activity and is well tolerated in patients with advanced MTC. Additional prospective studies of this regimen for MTC are required.