Preliminary results of a Phase II study: combined systemic polychemotherapy and intrathecal treatment with liposomal cytarabine in patients with primary CNS lymphoma ≥60 years

Objectives: To evaluate response rate, event free survival, overall survival, and toxicity in primary central nervous system lymphoma (PCNSL) after a combined systemic and intrathecal chemotherapy in patients ≥60 years.

Patients and methods: From 11/2005 to 03/2009, 70 patients with PCNSL (median age 67 years) were enrolled in phase II study evaluating systemic polychemotherapy combined with intrathecal application of liposomal cytarabine. All patients were 60 years of age or older at time of diagnosis. A high-dose methotrexate (MTX) (cycles 1,2,4,5) and cytarabine (ara-C) (cycles 3,6) based systemic therapy (including dexamethasone, vinca-alkaloids, ifosfamide and cyclophosphamide) was combined with liposomal cytarabine administered intrathecally via lumbar puncture once during each treatment cycle.

Results: Until March 2009, 69 patients were enrolled, 56 were evaluable for response. Of these, 27 (48%) achieved complete response (CR) or unconfirmed complete response (CRu), 8 (14%) partial response (PR), and 10 (18%) progressed under therapy. Six (11%) out of 56 patients died due to treatment-related complications. In five (9%) of 56 patients therapy had do be discontinued due to severe treatment related complications. Follow-up is one to 35 months (median 9 months). Kaplan Meier estimates for median event free survival (EFS) and median progression free survival in responding patients are 9 months, and 14 months, respectively. Median overall survival has not been reached yet. The 5-year survival fraction is 55%.

Conclusions: As these preliminary results show, primary chemotherapy based on high-dose MTX and ara-C combined with intrathecal application of liposomal cytarabine is efficient in PCNSL. The results presented are comparable with results from other treatment studies for elderly patients published so far.