Expert guidance on prophylaxis and treatment of dermatologic adverse events with Tumor Treating Fields (TTFields) therapy in the thoracic region

Tumor Treating Fields (TTFields) Therapy in Unresectable Pleural Mesothelioma: Overview of Efficacy, Safety, and Future Outlook

OPINION STATEMENT

Pleural mesothelioma is an incurable cancer with unmet diagnostic and therapeutic needs. Due to its pattern of local spread, few patients are candidates for multimodality treatment and thus most patients only receive systemic therapy. Chemotherapy (pemetrexed plus platinum) was standard of care until the recent addition of immunotherapy (nivolumab plus ipilimumab, or pembrolizumab plus chemotherapy) as further first-line option. Physicians treating pleural mesothelioma should be aware of another option with Tumor Treating Fields (TTFields) therapy, a locoregionally-applied therapy utilizing electric fields generated by a portable medical device, and delivered to the tumor by skin-placed arrays. TTFields therapy delivered to the thorax using the NovoTTF- 100L device concomitant with pemetrexed and platinum agent is approved for unresectable pleural mesothelioma in the US, and received Conformité Européenne certification in Europe, based on results from the phase 2 STELLAR study (EF- 23; NCT02397928), where TTFields-related toxicity was limited to mild-to-moderate reversible skin reactions. Overall survival in the STELLAR study with TTFields therapy was 18.2 months, with further post-hoc analysis showing extended survival in patients with epithelioid histology. Within the evolving landscape of systemic treatments, TTFields therapy represents a novel and clinically versatile therapeutic option in the battle against pleural mesothelioma without introducing additional toxicities other than mild-to-moderate skin irritation. While promising, additional research is needed to optimize clinical application of TTFields therapy in patients with pleural mesothelioma, such as identifying the molecular determinants of therapy efficacy, and further investigation into the safe and effective delivery of TTFields therapy together with systemic agents, including immunotherapies.

Tumor Treating Fields therapy in platinum-resistant ovarian cancer: Results of the ENGOT-ov50/GOG-3029/INNOVATE-3 pivotal phase 3 randomized study

PURPOSE

Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression. The pivotal, phase 3 ENGOT-ov50/GOG-3029/INNOVATE-3 study evaluated efficacy and safety of TTFields therapy with paclitaxel (PTX) vs PTX in patients with platinum-resistant ovarian cancer (PROC).

PATIENTS AND METHODS

Adult patients with PROC with ≤ 5 total prior lines of therapy (LOT), including ≤ 2 prior LOT for platinum-resistant disease, and ECOG PS of 0-1 were randomized 1:1 to receive TTFields (200 kHz; ≥ 18 h/day) + PTX (80 mg/m2 weekly) or PTX. Primary endpoint was overall survival (OS). Exploratory post-hoc analyses assessed OS in pegylated liposomal doxorubicin (PLD)-naive patients.

RESULTS

Between March 2019 and November 2021, 558 patients (ECOG PS 0, 60.2 %; median [range] age, 62 [22-91] years) were assigned TTFields+PTX (n = 280) or PTX (n = 278). 24.4 % had 4 + prior LOT. Median OS was 12.2 months with TTFields+PTX vs 11.9 months with PTX (HR, 1.01; 95 % CI, 0.83-1.24; p = 0.89). Grade ≥ 3 adverse events (AEs) were similar between treatment groups. Grade 1/2 device-related skin AEs occurred in 83.6 % of patients receiving TTFields therapy. In exploratory post-hoc analysis in PLD-naive patients, median OS was 16 months with TTFields+PTX (n = 113) vs 11.7 months with PTX (n = 88; nominal HR, 0.67; 95 % CI, 0.49-0.94; p = 0.03).

CONCLUSIONS

No new safety signals were identified. TTFields+PTX did not significantly improve OS compared with PTX in the intent-to-treat population. An exploratory post-hoc analysis suggests a potentially favorable benefit-risk profile for TTFields therapy in PLD-naive patients.

Recent advances in Tumor Treating Fields (TTFields) therapy for glioblastoma

Tumor Treating Fields (TTFields) therapy is a locoregional, anticancer treatment consisting of a noninvasive, portable device that delivers alternating electric fields to tumors through arrays placed on the skin. Based on efficacy and safety data from global pivotal (randomized phase III) clinical studies, TTFields therapy (Optune Gio) is US Food and Drug Administration-approved for newly diagnosed (nd) and recurrent glioblastoma (GBM) and Conformité Européenne-marked for grade 4 glioma. Here we review data on the multimodal TTFields mechanism of action that includes disruption of cancer cell mitosis, inhibition of DNA replication and damage response, interference with cell motility, and enhancement of systemic antitumor immunity (adaptive immunity). We describe new data showing that TTFields therapy has efficacy in a broad range of patients, with a tolerable safety profile extending to high-risk subpopulations. New analyses of clinical study data also confirmed that overall and progression-free survival positively correlated with increased usage of the device and dose of TTFields at the tumor site. Additionally, pilot/early phase clinical studies evaluating TTFields therapy in ndGBM concomitant with immunotherapy as well as radiotherapy have shown promise, and new pivotal studies will explore TTFields therapy in these settings. Finally, we review recent and ongoing studies in patients in pediatric care, other central nervous system tumors and brain metastases, as well as other advanced-stage solid tumors (ie, lung, ovarian, pancreatic, gastric, and hepatic cancers), that highlight the broad potential of TTFields therapy as an adjuvant treatment in oncology.

Optimized Methods to Quantify Tumor Treating Fields (TTFields)-Induced Permeabilization of Glioblastoma Cell Membranes

Glioblastoma (GBM) is a lethal primary brain cancer with a 5.6% five-year survival rate. Tumor treating fields (TTFields) are alternating low-intensity electric fields that have demonstrated a GBM patient survival benefit. We previously reported that 0.5-24 h of TTFields exposure resulted in an increased uptake of FITC-dextran fluorescent probes (4-20 kDa) in human GBM cells. However, this approach, in which a fluorescence plate-based detector is used to evaluate cells attached to glass coverslips, cannot distinguish FITC-dextran uptake in live vs. dead cells. The goal of the study was to report the optimization and validation of two independent methods to quantify human GBM cell membrane permeabilization induced by TTFields exposure. First, we optimized flow cytometry by measuring mean fluorescence intensity at 72 h for 4 kDa (TTFields 6726 ± 958.0 vs. no-TTFields 5093 ± 239.7, p = 0.016) and 20 kDa (7087 ± 1137 vs. 5055 ± 897.8, p = 0.031) probes. Second, we measured the ratio of lactate dehydrogenase (LDH) to cell viability (measured using the CellTiter-Glo [CTG] viability assay); the LDH/CTG ratio was higher under TTFields (1.47 ± 0.15) than no-TTFields (1.08 ± 0.08) conditions, p < 0.0001. The findings using these two independent methods reproducibly demonstrated their utility for time-dependent evaluations. We also showed that these methods can be used to relate the cell membrane-permeabilizing effects of the non-ionizing radiation of TTFields to that of an established cell membrane permeabilizer, the non-ionic detergent Triton-X-100. Evaluating carboplatin ± TTFields, the LDH/CTG ratio was significantly higher in the TTFields vs. no-TTFields condition at each carboplatin concentration (0-30 µM), p = 0.014. We successfully optimized and validated two cost-effective methods to reproducibly quantify TTFields-induced human GBM cancer cell membrane permeabilization.

Global post‑marketing safety surveillance of Tumor Treating Fields (TTFields) therapy in over 25,000 patients with CNS malignancies treated between 2011-2022

BACKGROUND

Tumor Treating Fields (TTFields) are alternating electric fields that disrupt cancer cell processes. TTFields therapy is approved for recurrent glioblastoma (rGBM), and newly-diagnosed (nd) GBM (with concomitant temozolomide for ndGBM; US), and for grade IV glioma (EU). We present an updated global, post-marketing surveillance safety analysis of patients with CNS malignancies treated with TTFields therapy.

METHODS

Safety data were collected from routine post-marketing activities for patients in North America, Europe, Israel, and Japan (October 2011-October 2022). Adverse events (AEs) were stratified by age, sex, and diagnosis.

RESULTS

Overall, 25,898 patients were included (diagnoses: ndGBM [68%], rGBM [26%], anaplastic astrocytoma/oligodendroglioma [4%], other CNS malignancies [2%]). Median (range) age was 59 (3-103) years; 66% patients were male. Most (69%) patients were 18-65 years; 0.4% were < 18 years; 30% were > 65 years. All-cause and TTFields-related AEs occurred in 18,798 (73%) and 14,599 (56%) patients, respectively. Most common treatment-related AEs were beneath-array skin reactions (43%), electric sensation (tingling; 14%), and heat sensation (warmth; 12%). Treatment-related skin reactions were comparable in pediatric (39%), adult (42%), and elderly (45%) groups, and in males (41%) and females (46%); and similar across diagnostic subgroups (ndGBM, 46%; rGBM, 34%; anaplastic astrocytoma/oligodendroglioma, 42%; other, 40%). No TTFields-related systemic AEs were reported.

CONCLUSIONS

This long-term, real-world analysis of > 25,000 patients demonstrated good tolerability of TTFields in patients with CNS malignancies. Most therapy-related AEs were manageable localized, non-serious skin events. The TTFields therapy safety profile remained consistent across subgroups (age, sex, and diagnosis), indicative of its broad applicability.

Long-Term Survival in Hepatocellular Carcinoma following Second-Line Tumor Treating Fields Therapy and Sorafenib: A Case Report

Introduction

Hepatocellular carcinoma (HCC) is an aggressive solid tumor associated with high mortality. Surgery is the main treatment consideration for early disease, but patients who present with locally advanced or metastatic HCC at diagnosis have limited treatment options. There has been great progress in locoregional, immunotherapy, and targeted treatments for advanced HCC. Standard of care for HCC has changed due to results demonstrating safety and efficacy in phase 3 studies, namely, for atezolizumab concomitant with bevacizumab. Nonetheless, additional therapeutic approaches are still warranted to further increase overall survival in HCC. A first-in-class treatment option investigated in patients with HCC is Tumor Treating Fields (TTFields) therapy, which is delivered locoregionally to the tumor site from a portable medical device. TTFields are electric fields that interfere with critical cancer cell processes, hindering tumor progression.

Case Presentation

Here, we report on a case study of a 62-year-old male patient with HCC receiving TTFields concomitant with sorafenib as second-line therapy. Although the patient experienced adverse events with previous nivolumab, they achieved a complete response and continued on treatment for 51 months until disease progression, which led to treatment cessation. We report that during 39 months of subsequent treatment with TTFields therapy and sorafenib, the patient experienced a good quality of life, low systemic toxicity, and stable disease following a partial response.

Conclusions

These promising findings, along with those of the pilot phase 2 HEPANOVA clinical study, warrant further investigation of TTFields therapy in HCC.

Efficacy of tumour-treating fields therapy in recurrent glioblastoma: A narrative review of current evidence

Recurrent Glioblastoma presents a formidable challenge in oncology due to its aggressive nature and limited treatment options. Tumour-Treating Fields (TTFields) Therapy, a novel therapeutic modality, has emerged as a promising approach to address this clinical conundrum. This review synthesizes the current evidence surrounding the efficacy of TTFields Therapy in the context of recurrent Glioblastoma. Diverse academic databases were explored to identify relevant studies published within the last decade. Strategic keyword selection facilitated the inclusion of studies focusing on TTFields Therapy's efficacy, treatment outcomes, and patient-specific factors. The review reveals a growing body of evidence suggesting the potential clinical benefits of TTFields Therapy for patients with recurrent Glioblastoma. Studies consistently demonstrate its positive impact on overall survival (OS) and progression-free survival (PFS). The therapy's safety profile remains favorable, with mild to moderate skin reactions being the most commonly reported adverse events. Our analysis highlights the importance of patient selection criteria, with emerging biomarkers such as PTEN mutation status influencing therapy response. Additionally, investigations into combining TTFields Therapy with other treatments, including surgical interventions and novel approaches, offer promising avenues for enhancing therapeutic outcomes. The synthesis of diverse studies underscores the potential of TTFields Therapy as a valuable addition to the armamentarium against recurrent Glioblastoma. The narrative review comprehensively explains the therapy's mechanisms, clinical benefits, adverse events, and future directions. The insights gathered herein serve as a foundation for clinicians and researchers striving to optimize treatment strategies for patients facing the challenging landscape of recurrent Glioblastoma.

Enhancing glioblastoma treatment through the integration of tumor-treating fields

Glioblastoma (GBM) represents a significant therapeutic challenge due to its aggressive nature. Tumor Treating Fields (TTFields) present a promising approach to GBM therapy. The primary mechanism of TTFields, an antimitotic effect, alongside numerous indirect effects including increased cell membrane permeability, signifies their potential in combination with other treatment modalities. Current combinations often include chemotherapy, particularly with temozolomide (TMZ), however, emerging data suggests potential synergy with targeted therapies, radiotherapy, and immunotherapy as well. TTFields display minimal side effects, predominantly skin-related, posing no significant barrier to combined therapies. The effectiveness of TTFields in GBM treatment has been demonstrated through several post-registration studies, advocating for continued research to optimize overall survival (OS) and progression-free survival (PFS) in patients, as opposed to focusing solely on quality of life.

Tumor Treating Fields therapy with standard systemic therapy versus standard systemic therapy alone in metastatic non-small-cell lung cancer following progression on or after platinum-based therapy (LUNAR): a randomised, open-label, pivotal phase 3 study

BACKGROUND

Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell survival, leading to immunogenic cell death and enhanced antitumour immune response. In preclinical models of non-small-cell lung cancer, TTFields amplified the effects of chemotherapy and immune checkpoint inhibitors. We report primary results from a pivotal study of TTFields therapy in metastatic non-small-cell lung cancer.

METHODS

This randomised, open-label, pivotal phase 3 study recruited patients at 130 sites in 19 countries. Participants were aged 22 years or older with metastatic non-small-cell lung cancer progressing on or after platinum-based therapy, with squamous or non-squamous histology and ECOG performance status of 2 or less. Previous platinum-based therapy was required, but no restriction was placed on the number or type of previous lines of systemic therapy. Participants were randomly assigned (1:1) to TTFields therapy and standard systemic therapy (investigator's choice of immune checkpoint inhibitor [nivolumab, pembrolizumab, or atezolizumab] or docetaxel) or standard therapy alone. Randomisation was performed centrally using variable blocked randomisation and an interactive voice-web response system, and was stratified by tumour histology, treatment, and region. Systemic therapies were dosed according to local practice guidelines. TTFields therapy (150 kHz) was delivered continuously to the thoracic region with the recommendation to achieve an average of at least 18 h/day device usage. The primary endpoint was overall survival in the intention-to-treat population. The safety population included all patients who received any study therapy and were analysed according to the actual treatment received. The study is registered with ClinicalTrials.gov, NCT02973789.

FINDINGS

Between Feb 13, 2017, and Nov 19, 2021, 276 patients were enrolled and randomly assigned to receive TTFields therapy with standard therapy (n=137) or standard therapy alone (n=139). The median age was 64 years (IQR 59-70), 178 (64%) were male and 98 (36%) were female, 156 (57%) had non-squamous non-small-cell lung cancer, and 87 (32%) had received a previous immune checkpoint inhibitor. Median follow-up was 10·6 months (IQR 6·1-33·7) for patients receiving TTFields therapy with standard therapy, and 9·5 months (0·1-32·1) for patients receiving standard therapy. Overall survival was significantly longer with TTFields therapy and standard therapy than with standard therapy alone (median 13·2 months [95% CI 10·3-15·5] vs 9·9 months [8·1-11·5]; hazard ratio [HR] 0·74 [95% CI 0·56-0·98]; p=0·035). In the safety population (n=267), serious adverse events of any cause were reported in 70 (53%) of 133 patients receiving TTFields therapy plus standard therapy and 51 (38%) of 134 patients receiving standard therapy alone. The most frequent grade 3-4 adverse events were leukopenia (37 [14%] of 267), pneumonia (28 [10%]), and anaemia (21 [8%]). TTFields therapy-related adverse events were reported in 95 (71%) of 133 patients; these were mostly (81 [85%]) grade 1-2 skin and subcutaneous tissue disorders. There were three deaths related to standard therapy (two due to infections and one due to pulmonary haemorrhage) and no deaths related to TTFields therapy.

INTERPRETATION

TTFields therapy added to standard therapy significantly improved overall survival compared with standard therapy alone in metastatic non-small-cell lung cancer after progression on platinum-based therapy without exacerbating systemic toxicities. These data suggest that TTFields therapy is efficacious in metastatic non-small-cell lung cancer and should be considered as a treatment option to manage the disease in this setting.

FUNDING

Novocure.

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

Multi-Institutional Patterns of Use of Tumor-Treating Fields for Patients with Malignant Pleural Mesothelioma

(1) Background: The objective of this analysis was to evaluate the device usage rates and patterns of use regarding Tumor-Treating Fields (TTFields) for patients with malignant pleural mesothelioma (MPM) throughout the US. (2) Methods: We evaluated de-identified data from 33 patients with MPM enrolled in FDA-required HDE protocols at 14 institutions across the US from September 2019 to March 2022. (3) Results: The median number of total TTFields usage days was 72 (range: 6-649 days), and the total treatment duration was 160 months for all patients. A low usage rate (defined as less than 6 h per day, 25%) was observed in 34 (21.2%) months. The median TTFields usage in the first 3 months was 12 h per day (range: 1.9-21.6 h), representing 50% (range: 8-90%) of the potential daily duration. The median TTFields usage after 3 months decreased to 9.1 h per day (range: 3.1-17 h), representing 38% (range: 13-71%) of the daily duration, and was lower than usage in the first 3 months (p = 0.01). (4) Conclusions: This study represents the first multicenter analysis of real-world TTFields usage based on usage patterns for MPM patients in clinical practice. The real-world usage level was lower than the suggested daily usage. Further initiatives and guidelines should be developed to evaluate the impact of this finding on tumor control.