[Concomitant chemoradiotherapy and malignant glial tumors in the adult]

Phase I study of topotecan in combination with concurrent radiotherapy in adults with glioblastoma

A phase I study was performed to determine the maximum tolerated dose and the recommended dose of continuous intravenous infusion of topotecan in combination with radiotherapy (RT) in patients with previously untreated glioblastoma multiforme (GBM). Twenty patients with histologically proven GBM and 1 with rhabdoid tumor were enrolled. After surgery or stereotactic biopsy, patients received cranial RT (60 Gy/30 fractions/40 days) and 3 cycles of topotecan as continuous infusion (CIV) from day 1 to 5 on weeks 1, 3, and 5 during RT. The dose of topotecan was escalated from 0.6 to 1.0 mg/m2/day. Four dose levels were tested. One grade 4 thrombocytopenia was seen at level 1 (topotecan dose 0.6 mg/m2/day; 6 patients). No dose-limiting toxicity was seen at level 2 (0.8 mg/m2/day; 3 patients) or an intermediate level of 2 bis (0.9 mg/m2/day; 6 patients). Six patients were included at level 3 (1.0 mg/m2/day), 4 of whom experienced dose-limiting toxicities, including 3 episodes of grade 4 thrombocytopenia, 1 platelet transfusion, 1 febrile neutropenia, and 1 grade 4 neutropenia of more than 7 days. Eighty percent of patients with GBM were alive at 12 months. The dose-limiting toxicity of topotecan administered as CIV for 5 days every 2 weeks is hematological. The maximum tolerated dose is 1.0 mg/m2/day and the recommended dose is 0.9 mg/m2/day. A phase II trial using the recommended dose of topotecan is ongoing.

Response to a phase II study of concomitant-to-sequential use of etoposide and radiation therapy in newly diagnosed malignant gliomas

We evaluated the antitumor efficacy of and patient tolerance to a phase II study of concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas. Fifty-two supratentorial malignant glioma patients were enrolled in this phase II study between May 1995 and May 1998. Standard cranial irradiation and six courses of etoposide (100 mg/m2 - xdays 1-3) were administered. The first course of etoposide was given on days 1 to 3 of radiotherapy and was resumed in the week following the end of radiotherapy. Treatment was consolidated by further courses of etoposide every 4 weeks. Fifty-one patients were assessable for toxicity, response, and survival. A complete surgical resection was only noted for 17 patients. Six patients had a confirmed complete response, and eight patients displayed a partial response. Six patients progressed within the first 3 months of starting treatment. The rate of objective response for assessable patients with residual tumor was 41.1%. Hematologic toxicity was mild; grade 3 or 4 neutropenia was noted in five patients, without sepsis. The overall median survival time (MST) was 12.5 months, and the mean survival of this population was 14.9 months. These results suggest a certain efficacy of this regimen testing a concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas, and that continued evaluation of this combination is warranted, especially because this treatment is also well tolerated.