Showing papers by "Joel M. Reid published in 1998"

Phase I study of temozolomide in children and adolescents with recurrent solid tumors: a report from the Children's Cancer Group.

Abstract: PURPOSEThe Children's Cancer Group conducted a phase I trial of temozolomide stratified by prior craniospinal irradiation (CSI).PATIENTS AND METHODSChildren and adolescents with recurrent or progressive cancer were enrolled. Temozolomide was administered orally daily for 5 days, with subsequent courses administered every 21 to 28 days after full hematologic recovery. Dose levels tested included 100, 150, 180, 215, 245, and 260 mg/m2 daily.RESULTSTwenty-seven patients on the non-CSI stratum were assessable for hematologic toxicity. During the first three dose levels (100, 150, and 180 mg/m2 daily), only grades 1 and 2 hematologic toxicity occurred. One patient at 215 mg/m2 daily had grade 3 hematologic toxicity. Three of eight patients (38%) treated at 245 to 260 mg/m2 daily had dose-limiting toxicity (DLT), which included both neutropenia and thrombocytopenia. Twenty-two patients on the CSI stratum were assessable for hematologic toxicity. Hematologic DLT occurred in one of six patients (17%) at 100 mg/m2...

6-Aminonicotinamide sensitizes human tumor cell lines to cisplatin.

Abstract: The nicotinamide analogue 6-aminonicotinamide (6AN) is presently undergoing evaluation as a potential modulator of the action of various antineoplastic treatments. Most previous studies of this agent have focused on a three-drug regimen of chemical modulators that includes 6AN. In the present study, the effect of single-agent 6AN on the efficacy of selected antineoplastic drugs was assessed in vitro. Colony-forming assays using human tumor cell lines demonstrated that pretreatment with 30-250 microM 6AN for 18 h resulted in increased sensitivity to the DNA cross-linking agent cisplatin, with 6-, 11-, and 17-fold decreases in the cisplatin dose that diminishes colony formation by 90% being observed in K562 leukemia cells, A549 non-small cell lung cancer cells, and T98G glioblastoma cells, respectively. Morphological examination revealed increased numbers of apoptotic cells after treatment with 6AN and cisplatin compared to cisplatin alone. 6AN also sensitized cells to melphalan and nitrogen mustard but not to chlorambucil, 4-hydroperoxycyclophosphamide, etoposide, or daunorubicin. In additional studies undertaken to elucidate the mechanism underlying the sensitization to cisplatin, atomic absorption spectroscopy revealed that 6AN had no effect on the rate of removal of platinum (Pt) adducts from DNA. Instead, 6AN treatment was accompanied by an increase in Pt-DNA adducts that paralleled the degree of sensitization. This effect was not attributable to 6AN-induced decreases in glutathione or NAD+, because other agents that depleted these detoxification cofactors (buthionine sulfoximine and 3-acetylpyridine, respectively) did not increase Pt-DNA adducts. On the contrary, 6AN treatment increased cellular accumulation of cisplatin. Further experiments revealed that 6AN was metabolized to 6-aminonicotinamide adenine dinucleotide (6ANAD+). Concurrent administration of nicotinamide and 6AN had minimal effect on cellular 6AN accumulation but abolished the formation of 6ANAD+, the increase in Pt-DNA adducts, and the sensitizing effect of 6AN in clonogenic assays. These observations identify 6AN as a potential modulator of cisplatin sensitivity and suggest that the 6AN metabolite 6ANAD+ exerts this effect by increasing cisplatin accumulation and subsequent formation of Pt-DNA adducts.

Effect of pyrazoloacridine (NSC 366140) on DNA topoisomerases I and II.

Abstract: Pyrazoloacridine (PA), an acridine congener with an unknown mechanism of action, has shown selective activity against solid tumor cells, cytotoxicity in noncycling and hypoxic cells, and promising antitumor activity in Phase I clinical trials. In the present study, the effect of PA on topoisomerase (topo) activity was evaluated using yeast strains lacking functional topo I or II, mammalian cell nuclear extracts, purified samples of mammalian topo I and topo II, and intact mammalian tissue culture cells. Clonogenic assays revealed that PA cytotoxicity in yeast strains was unaffected by selective loss of topo I or topo II activity. On the other hand, enzyme assays revealed that 2-4 microM PA abolished the catalytic activity of both topo I and topo II in vitro. In contrast to topotecan and etoposide, PA did not stabilize covalent topo-DNA complexes. Instead, PA inhibited topotecan-induced stabilization of covalent topo I-DNA complexes and etoposide-induced stabilization of topo II-DNA complexes in vitro and in intact cells. Consistent with these results, colony-forming assays indicated that short-term PA exposure inhibited the cytotoxicity of topotecan and etoposide, whereas prolonged PA exposure was itself toxic to these cells. Accumulation studies revealed that PA was concentrated as much as 250-fold in drug-treated cells, resulting in intranuclear concentrations that far exceeded those required to inhibit topo I and topo II. Collectively, these results not only suggest that PA can target both topo I and topo II at clinically achievable concentrations but also indicate that its mechanism is distinct from topo I and topo II poisons presently licensed for clinical use.

Clinical and pharmacokinetic studies of high-dose levamisole in combination with 5-fluorouracil in patients with advanced cancer

Abstract: Purpose: To determine the maximum tolerable dose (MTD) and activity of levamisole administered concurrently with 5-fluorouracil (5-FU) in a standard 5-day course. To determine the pharmacokinetics of levamisole during the course of treatment. Patients and methods: Levamisole was administered to 38 patients orally three times a day for 5 days concurrently with a course of 5-FU administered daily by rapid intravenous injection for 5 days. Toxicity was evaluated in 20 patients who received escalating doses of levamisole. The activity of the combination was evaluated in 18 patients who received levamisole at the MTD with 5-FU. The pharmacokinetics of levamisole were characterized in ten patients at the MTD level. Results: Intractable vomiting, confusion and vertigo were the major dose-limiting toxicities. The MTD of oral levamisole was 100 mg/m2 administered three times a day concurrently with 450 mg/m2 per day intravenous 5-FU for 5 consecutive days. Partial responses lasting 5 and 11 months were observed in 2/18 patients with measurable disease at the MTD. Peak plasma concentrations of 1 μg/ml (range 0.6–1.3 μg/ml) were achieved 90 min (range 60–360 min) after an oral dose of 100 mg/m2 levamisole with a 3.5-fold accumulation noted following 4 days of administration. Peak plasma concentrations of p-hydroxylevamisole were about 5% of parent drug. Little parent drug (2–5%) was detected in urine. Conclusions: Levamisole may be administered safely with 5-FU at doses which are up to four to five times greater than those presently given in conventional regimens. The recommended dose of levamisole combined with 5-FU for future research protocols is 75 mg/m2 t.i.d for 5 days.

Phase I and pharmacokinetic study of preirradiation chemotherapy with BCNU, cisplatin, etoposide, and accelerated radiation therapy in patients with high-grade glioma

Abstract: Purpose: We conducted a Phase I study of bischloroethylnitrosourea (BCNU), cisplatin, and oral etoposide administered prior to and during accelerated hyperfractionated radiation therapy in newly diagnosed high-grade glioma. Pharmacokinetic studies of oral etoposide were also done. Methods and Materials: Patients started chemotherapy after surgery but prior to definitive radiation therapy (160 cGy twice daily × 15 days; 4800 cGy total). Initial chemotherapy consisted of BCNU 40 mg/m 2 days 1–3, cisplatin 30 mg/m 2 days 1–3 and 29–31, and etoposide 50 mg orally days 1–14 and 29–42, repeated in 8 weeks concurrent with radiation therapy. BCNU 200 mg/m 2 every 8 weeks × 4 cycles was given after radiation therapy. Results: Sixteen patients, 5 with grade 3 anaplastic astrocytoma and 11 with glioblastoma were studied. Grade 3–4 leukopenia (38%) and thrombocytopenia (31%) were dose-limiting. Other toxicities were anorexia (81%), nausea (94%), emesis (56%), alopecia (88%), and ototoxicity (38%). The maximum tolerated dose was BCNU 40 mg/m 2 days 1–3, cisplatin 20 mg/m 2 days 1–3 and 29–31, and oral etoposide 50 mg days 1–21 and 29–49 prior to radiation therapy and repeated in 8 weeks with the start of radiation therapy followed by BCNU 200 mg/m 2 every 8 weeks for 4 cycles. Median time to progression and survival were 13 and 14 months respectively. Responses occurred in 2 of 9 (22%) patients with evaluable disease. In pharmacokinetic studies, all patients achieved plasma concentrations of >0.1 μg/ml etoposide (the in vitro radiosensitizing threshold), following a 50 mg oral dose. The mean ± SD 2 hr and 6 hr plasma concentrations were 0.92 ± 0.43 μg/ml and 0.36 ± 0.12 μg/ml, respectively. Estimated duration of exposure to >0.1 μg/ml etoposide was 10–17 hr. Conclusions: Preirradiation chemotherapy with BCNU, cisplatin, and oral etoposide with accelerated hyperfractionated radiation therapy in high-grade gliomas is feasible and merits further investigation. Sustained radiosensitizing concentrations can be achieved with low oral doses of etoposide.

Phase I study of the duocarmycin semisynthetic derivative KW-2189 given daily for five days every six weeks.

Abstract: The duocarmycins represent a new group of antitumor antibiotics produced by Streptomyces that bind to the minor groove of DNA. KW-2189 is a water-soluble semisynthetic derivative of duocarmycin B2, with significant activity in murine and human tumor models. We conducted a Phase I trial of KW-2189 in patients who had solid tumors that were refractory to standard chemotherapy or for whom no more effective therapy existed. KW-2189 was administered as a rapid i.v. bolus daily for 5 days every 6 weeks. Twenty-two patients were enrolled and received a total of 31 cycles of KW-2189. Leukopenia, neutropenia, and thrombocytopenia were the dose-limiting toxicities, with nadirs occurring at medians of 36, 38, and 29 days, respectively, at the 0.04 mg/m2/day dose level. Nonhematological toxicities were mild, although one patient developed grade 3 fatigue. Four patients had stable disease over two to four cycles of treatment and showed no cumulative toxicity. The mean t1/2, plasma clearance, and steady-state volume of distribution were 13.5 min, 1,287 ml/min/m2, and 10,638 ml/m2, respectively. Pharmacokinetics were similar on days 1 and 5, with no drug accumulation in plasma. The active metabolite DU-86 was not consistently found in patient plasma. For Phase II trials, when the 5 days every 6 weeks schedule was used, 0.04 mg/m2/day KW-2189 appears to be the maximal tolerated dose, especially for patients who have received prior chemotherapy. At this dose level, the drug was well tolerated, and the toxicities were acceptable.