Combination treatment using tumor treating fields (TTFields) with temozolomide, bevacizumab, and irinotecan chemotherapy improves overall survival (OS) in patients with recurrent glioblastoma with manageable safety, according to data published alongside the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting. 

The retrospective review investigated the combination regimen using medical records of adult patients with glioblastoma treated at the University of Texas Health Science Center between 2011 and 2021. The primary outcomes were OS and occurrence of serious adverse events (AEs).

Kaplan-Meier estimates and log-rank tests were used for statistical analyses. Data were compared to that from published studies on glioblastoma.

A total of 500 eligible patients were identified and separated in 3 groups based on treatment received at glioblastoma recurrence: with temozolomide, bevacizumab, and irinotecan chemotherapy plus TTFields (n = 49; group 1), temozolomide, bevacizumab, and irinotecan chemotherapy alone (n = 51; group 2) and physician’s choice group (n = 400; group 3).

Median OS from diagnosis was 21 months in group 1, 24.5 months in group 2, and 13 months in group 3 (hazard ratio [HR], 0.51; 95% confidence interval [CI], 0.33 to 0.78, P = .002). Among patients with IDH-1 wild type disease, median OS was 20 months in group 1 (n = 42), 24 months in group 2 (n = 47), and 13 months in group 3 (n = 352; HR, 0.54; 95% CI, 0.33 to 0.90; P = .017).

“Other contributing factors that may improve OS include a team of brain tumor treating physicians working together for timely identification of [glioblastoma at recurrence and implementation of best treatment accordingly, with combination of modalities, such as stereotactic radiosurgery, salvage radiation, laser ablation, or craniotomy followed by chemotherapy and TTFields,” wrote Joshua Nahm, University of Texas Health Science Center at Houston, and colleagues.

Serious AEs in group 1, group 2, and group 3 were grade 3 lymphopenia, (51% vs 41.2% vs 31.1%, respectively), grade 3 hypertension (26.5% vs 21.6% vs 13.1%), and grade 3 leukopenia (10.2% vs 9.8% vs 13.1%).

“Compared with published results and physician’s choice group, the data suggests that both [temozolomide, bevacizumab, and irinotecan chemotherapy] plus TTFields and TBI regimens increase OS of glioblastoma patients with manageable and reversible side effects,” wrote Mr Nahm and coauthors, adding “Further research of larger sample sizes and prospective clinical trials are warranted to evaluate the two treatment regimens.”

Source:

Nahm J, Sinha M, Highberg Schumann E, Vu M, Hsu SH, Zhu J. Overall survival in patients with recurrent glioblastomas with combination chemotherapy and tumor treating fields (TTF). Presented at 2023 ASCO Annual Meeting; June 2-6, 2023; Chicago, IL. Abstract e14067