Abstract 3252: TTFields combined with temozolomide and immunotherapy show long-term PFS on a GBM patients with multiple negative prognostic factors
Authors: Li Zhiyong , Zhang Xi'an , Que Tianshi , Yi Guozhong , Zhang Peidong , Zheng Haojie , Yuan Xi , Qi Songtao , Huang Guanglong 
Published: April 2023

Abstract
Glioblastoma (GBM) is a common CNS tumor with poor prognosis. The median progression-free survival (mPFS) of standard Stupp regimen was about 6.9 months. The 2-THE-TOP study suggested that a triple regimen of temozolomide (TMZ) combined with pembrolizumab and Tumor treating fields (TTFields) could further prolong the mPFS of newly diagnosed GBM to 12.1 months. Here we report a case showing long PFS from this triple regimen. In October 2019, a 60-year-old female patient was admitted to the hospital due to intermittent dizziness and headache with rapid progression of left limb weakness for more than 10 days. MRI showed a space-occupying lesion in the basal ganglia of the right temporal lobe, with obvious peritumoral edema involving the basal ganglia, posterolateral thalamus, and cerebral foot, with midline shift, demonstrating a high-grade glioma. Total resection of the tumor was performed on October 30, 2019. Pathological diagnosis was glioblastoma, IDH wild type, WHO grade 4. Next generation sequencing showed negative MGMT promoter methylation, TERT promoter mutation, PTEN mutation, CDK4 and EGFR amplification. TMZ concurrent chemoradiotherapy was initiated on November 19, 2019, followed by triple regimen of TMZ adjuvant chemotherapy (200mg/m2), pembrolizumab (200mg VD q3w) and TTFields in March 2020. During this period, the compliance of TTFields remained above 92%, which means the daily duration of TTFields was above 22.08 hours. Regular MRI review showed that the intracranial condition was stable, and there was no interruption of treatment due to treatment-related adverse reactions. No progression was found in the MRI reexamination in April 2022 but TTFields and TMZ chemotherapy were subsequently discontinued for the patient’s personal reasons, however, pembrolizumab monotherapy was maintained. In July 2022 she was hospitalized due to hemiplegia and the tumor recurrence was revealed in MRI, indicating a PFS of 33 months. She underwent tumor resection again and was histologically diagnosed as recurrent GBM on August 2,2022. After surgery, electric field therapy and immunotherapy were resumed. The patient was well recovered with a stable disease at the time of submitting this abstract. This patient had multiple negative prognostic factors of GBM. But under the combined regimen of electric field therapy, immunotherapy and chemotherapy, the disease control was maintained for up to 33 months, which is significantly prolonged compared to historical data of 12.1 months. The patient maintained TTFields for nearly 2 years, and tumor recurrence occurred 3 months after discontinuation of TTFields, indicating that continuous use of TTFields take great importance on disease control. Overall, our case of long-term PFS provides an important reference for the treatment of GBM patients with TTFields combined with immunotherapy and TMZ chemotherapy.
Citation Format: Zhiyong Li, Xi'an Zhang, Tianshi Que, Guozhong Yi, Peidong Zhang, Haojie Zheng, Xi Yuan, Songtao Qi, Guanglong Huang. TTFields combined with temozolomide and immunotherapy show long-term PFS on a GBM patients with multiple negative prognostic factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3252.