Salvage chemotherapy with cyclophosphamide for recurrent, temozolomide-refractory glioblastoma multiforme

The primary objective of the current prospective Phase II study of cyclophosphamide (CYC) in adult patients with recurrent, temozolomide-refractory glioblastoma multiforme was to evaluate 6-month progression-free survival (PFS).

Forty patients (28 men and 12 women) ages 28-67 years (median age, 51.5 years), with recurrent glioblastoma multiforme were treated. All patients had been treated previously with surgery and involved-field radiotherapy (median dose, 60 grays [Gy]; range, 59-61 Gy). In addition, all patients were treated adjuvantly with either nitrosourea-based chemotherapy (21 patients: procarbazine, lomustine, and vincristine in 13 patients; carmustine in 8 patients) or temozolomide (19 patients). Twenty-one patients who were treated previously with a nitrosourea were treated with temozolomide at the time of first recurrence. Twenty-one patients were treated with CYC at the time of second recurrence, and 19 patients were treated with CYC at the time of first recurrence. CYC was administered intravenously on 2 consecutive days (750 mg/m2 per day) every 4 weeks (operationally defined as a single cycle). Neurologic and neuroradiographic evaluations were performed every 8 weeks.

All patients were evaluable. In total, 170 cycles of CYC (median, 2 cycles; range, 2-12 cycles) were administered. CYC-related toxicity included alopecia in all patients (100%), anemia in 6 patients (3.5%), thrombocytopenia in 7 patients (4.1%), and neutropenia in 9 patients (5.3%). Four patients required transfusions (two required red blood cell transfusion, and two required platelet transfusion). One patient developed neutropenic fever without bacteriologic confirmation. No treatment-related deaths occurred. Seven patients (17.5%; 95% confidence interval [95% CI], 8-33%) exhibited a neuroradiographic partial response, 11 patients (27.5%; 95% CI, 15-44%) had stable disease, and 22 patients (55%) had progressive disease after a single cycle of CYC. The time to tumor progression ranged from 2 months to 18 months (median, 2 months). Survival ranged from 3 months to 24 months (median, 4 months). In patients with either a neuroradiographic response or stable disease (n = 18 [45%]), the median time to tumor progression was 6 months (range, 4-18 months; 95% CI, 6-8 months), and the median survival was 10 months (range, 5-24 months; 95% CI, 8-10 months). The 6-month PFS rate was 20%.

CYC exhibited modest efficacy with acceptable toxicity in the current cohort of adult patients with recurrent glioblastoma multiforme, all of whom had previously experienced treatment failure after temozolomide chemotherapy.