Abstract
Tumor Treating Fields therapy (TTFields; 200 kHz) is a noninvasive, locoregional, antimitotic treatment approved for newly diagnosed glioblastoma (ndGBM), recurrent (r) GBM, malignant pleural mesothelioma, and is being investigated in additional solid tumors. Approval in GBM was based on results of the phase 3 EF-11 (TTFields monotherapy; rGBM) and EF-14 (TTFields therapy/maintenance temozolomide; ndGBM), which showed clinical benefit without an increase in adverse events (AEs). Here we review post-marketing surveillance (PMS) data from patients with brain tumors who received TTFields therapy over an 11-year period. Unsolicited PMS data from patients with brain tumors who received TTFields therapy between October 2011 and March 2022, were included. Overall 23,822 patients were included in this analysis. Most patients (72%) were from North America; 24% from Europe, Middle East and Africa, and 4% from Japan. Birth year was available for 23,784 patients; of these, the average age at treatment start was 57 years (range: 3–103). Diagnoses were ndGBM (67%), rGBM (27%), astrocytoma (WHO grade 3; 4%) and other (2%). Overall, 71% of patients reported ≥ 1 AE, with the most common being skin reaction (42%), electric (tingling) sensation (14%), heat (warmth) sensation (12%), and seizure (11%). Furthermore, 56% of patients reported AEs possibly related to TTFields therapy, with the most frequently reported being skin reaction (42%), electric sensation (14%) and heat sensation (12%), occurring underneath the arrays. Numbers and types of AEs were comparable between age and diagnosis groups. PMS data from > 23,000 patients with brain tumors show that TTFields therapy (200 kHz) is well-tolerated, consistent with the known safety profile; no new safety signals were identified. TTFields therapy is not associated with systemic toxicity; most common possibly-related AEs are localized dermatologic events that can be managed with appropriate prophylaxis and treatment strategies.