Early relapses in primary CNS lymphoma after response to polychemotherapy without intraventricular treatment: results of a phase II study

Background A systemic and intraventricular polychemotherapy regimen (the Bonn protocol) without radiotherapy resulted in durable responses in 75% of patients < 60 years with primary CNS lymphoma (PCNSL), but was complicated by a high rate of Ommaya reservoir infections. Here, the efficacy and toxicity of this regimen without intraventricular treatment was evaluated in PCNSL. Patients and methods From August 2003 to November 2005, 18 patients with PCNSL < 60 years (median age, 53 years) were treated in a phase II trial with a high-dose methotrexate (MTX; cycles 1, 2, 4 and 5) and cytarabine (Ara-C; cycles 3 and 6) based systemic therapy including dexamethasone, vinca-alkaloids, ifosfamide and cyclophosphamide. Results Study accrual was prematurely stopped in November 2005 due to a high rate of early relapses. Seventeen of 18 patients were assessable for response: nine (53%) achieved complete response (CR), two (12%) complete response/unconfirmed (CRu) and two (12%) partial response (PR); four (24%) showed progressive disease (PD). One treatment was stopped due to toxicity. Median follow-up was 23 months, median response duration was only 10 months in responding patients, and median time to treatment failure (TTF) was 8 months in the whole group. Median overall survival (OS) has not been reached. Systemic toxicity was mainly hematologic. Conclusions In PCNSL patients < 60 years, polychemotherapy without intraventricular treatment results in a high response rate, but is associated with early relapses in the majority of cases. This is in contrast to the results achieved with the same protocol but with intraventricular treatment.