[Show abstract][Hide abstract] ABSTRACT: Dexamethasone. cytarabine (ara-C), and cisplatin (DHAP) can be used effectively to treat patients with non-Hodgkin's lymphoma (NHL). We hypothesized that substitution of cisplatin by oxaliplatin (L-OHP) could result in less toxicity and greater efficacy. L-OHP is active in patients with lymphoma. It produces mild myelosuppression and is devoid of renal toxicity. We report on a phase II study of dexamethasone, high-dose ara-C, and L-OHP (DHAOx) used to treat patients with NHL who were previously treated with chemotherapy.
Fifteen patients were given DHAOx. They had failed to achieve a CR with initial chemotherapy or had recurrent disease. DHAOx consisted of dexamethasone, 40 mg/day (days 1 to 4): L-OHP, 130 mg/m2 (day 1); and ara-C, 2,000 mg/m2 every 12 h (day 2). Treatment was repeated every 21 days.
Patients received a median of four courses of DHAOx. Myelosuppression and transient sensory peripheral neuropathy were the most prominent toxic effects. Serum creatinine levels did not increase in patients with normal renal function, nor in patients who had renal impairment before DHAOx. The median follow-up time from the start of DHAOx treatment was 17 months. Eight patients (53%) achieved a CR, and three patients (20%) had a PR. Responses were achieved by patients with lymphomas of various histologies that included mainly the follicular subtype, and by patients with and without resistance to prior chemotherapy. None of the eight responders have relapsed from CR at 4+. 6+, 14+, 15+, 19+, 20+, 24+, and 24+ months. They had various types of therapy after DHAOx. Disappearance of molecular markers was observed in all four patients who achieved a CR and whose tumor cells carried molecular abnormalities.
DHAOx possesses characteristics of toxicity which compare favorably to those reported with DHAP, and it is useful as a salvage treatment for patients with NHL. Larger studies are required to establish the therapeutic potential of the regimen.
Annals of Oncology 11/2001; 12(10):1439-43. · 7.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Potentiation of the cytotoxic activity of 5-fluorouracil (FUra) by folinic acid (5-HCO-H4folate) is due to elevation of the methylene tetrahydrofolate (CH2-H4folate) level, which increases the stability of the ternary complex of thymidylate synthase (TS), fluorodeoxyuridine monophosphate, and CH2-H4folate that inactivates the TS. Methionine deprivation results in the production of tetrahydrofolate (H4folate) and, subsequently, CH2-H4folate from methyl tetrahydrofolate, as a consequence of the induction of methionine synthesis. We hypothesized that the efficacy of FUra could be augmented by the combination of high-concentration 5-HCO-H4folate and recombinant methioninase (rMETase), a methionine-cleaving enzyme. Studies in vitro were performed with the cell line CCRF-CEM. Cytotoxic synergism of FUra + rMETase and FUra + 5-HCO-H4folate + rMETase was demonstrated with the combination index throughout a broad concentration range of FUra and rMETase. A subcytotoxic concentration of rMETase reduced the IC50 of FUra by a factor of 3.6, and by a factor of 7.5, in the absence and in the presence of 5-HCO-H4folate, respectively. 5-HCO-H4folate increased the intracellular concentrations of CH2-H4folate and H4folate from their baseline levels. Concentrations of folates were not changed by exposure to rMETase. Levels of free TS in cells treated with FUra + 5-HCO-H4folate and with FUra + rMETase were lower than those in cells exposed to FUra alone. The decrease of TS was still more pronounced in cells treated with FUra + 5-HCO-H4folate + rMETase. The synergism described in this study will be a basis for further exploration of combinations of fluoropyrimidines, folates, and rMETase.