abstractBACKGROUND: Oligodendroglial tumors are chemosensitive, with two-thirds of patients responding to PCV combination chemotherapy with procarbazine, lomustine (CCNU) and vincristine. Temozolomide (TMZ), a new alkylating and methylating agent has shown high response rates in recurrent anaplastic astrocytoma. We investigated this drug in recurrent oligodendroglial tumors (OD) and mixed oligoastrocytomas (OA) after prior PCV chemotherapy and radiation therapy. PATIENTS AND METHODS: In a prospective non-randomized multicenter phase II trial patients were treated with TMZ 150 mg/m(2) on days 1-5 in cycles of 28 days for 12 cycles. Eligible patients had a recurrence after prior PCV chemotherapy, with measurable and enhancing disease as shown by magnetic resonance imaging. Pathology and all responses were centrally reviewed. RESULTS: Thirty-two eligible patients were included. In four patients the pathology review did not confirm the presence of an OD or OA. Twelve of 24 patients [50%, 95% confidence interval (CI) 29% to 71%] evaluable for response to first-line PCV chemotherapy had responded to PCV. Temozolomide was in general well tolerated; the most frequent side-effects were hematological. One patient discontinued treatment due to toxicity. In seven of 28 patients (25%, 95% CI 11% to 45%) with histologically confirmed OD an objective response to TMZ was observed. Median time to progression for responding patients was 8.0 months. After 6 and 12 months from the start of treatment, 29% and 11% of patients, respectively, were still free from progression. CONCLUSIONS: TMZ may be regarded as the preferred second-line treatment in OD after failure of PCV chemotherapy. Further studies on TMZ in OD are indicated.text