Rechallenge temozolomide in glioma: A case series from India

Temozolomide (TMZ) is an integral part of upfront treatment of high-grade gliomas. It is administered postsurgery as concurrent therapy with radiation and subsequently as adjuvant chemotherapy for 6-12 cycles. It is unknown whether rechallenge of salvage TMZ in previously treated high-grade glioma has any efficacy.

Patients treated with salvage rechallenged TMZ between January 2015 and August 2016 were included for this retrospective analysis. SPSS version 20 was used for this analysis. Time to event analysis was performed using the Kaplan-Meier method. Progression-free survival (PFS) and overall survival (OS) were estimated. The maximum grade of toxicity was noted in accordance with CTCAE version 4.02.

A total of 23 patients were selected for analysis with the median age being 43 years (range: 26-69 years). The tumor histopathology at baseline was astrocytoma Grade 2 in 1 patient, oligodendroglioma Grade 2 in 3 patients, anaplastic astrocytoma in 7 patients, anaplastic oligodendroglioma in 2 patients, and glioblastoma in 10 patients. All of them had previously received TMZ. The median numbers of previous TMZ cycles received were 6 (4-18). The median time to failure postlast treatment was 24 months (5-72 months). The median number of cycles of rechallenged salvage TMZ administered was 6 cycles (range: 1-18). Grade 3-4 myelosuppression was seen in 3 patients (13.4%). The median PFS was 459 days (95% confidence interval: 212.1-705.9). The median OS was 25 months. Six-month OS and 1-year OS were 81.4% and 75.1%, respectively.

Rechallenge with TMZ in recurrent glioma that had previously responded to TMZ is associated with improvement in PFS and OS and has a sufficiently long disease-free interval.