Thermal safety and effectiveness of tumor treating fields’ delivery to the abdomen as determined by computational simulations

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Background: Tumor Treating Fields (TTFields), an antimitotic cancer treatment, utilizes low intensity (1-3 V/cm), intermediate frequency (100-300 kHz), alternating electric fields delivered non-invasively by transducer arrays placed on skin over tumor region. Safety of TTFields has been established in pancreatic cancer (Phase II study; PANOVA; NCT01971281). A Phase 3 study in locally-advanced pancreatic cancer (PANOVA-3) and a phase 2 study in hepatocellular cancer are ongoing. Preclinical studies suggest that TTFields’ intensity correlates with treatment efficacy. Simulations can determine the thermal safety of TTFields by evaluating tissue heating due to field absorption and resultant risk of thermal damage. We used computational simulations to study the effectiveness of field distribution and associated heating in realistic phantoms during TTFields delivery to the abdomen. Methods: Delivery of TTFields to computational phantoms of a male (DUKE 3.0), a female (ELLA 3.0) and an obese male (FATS 3.0) was simulated. For each phantom, 6-8 different transducer array layouts to the abdomen were tested. Specific Absorption Rate (SAR) levels were calculated to assess the risk of thermal damage to tissues, and compared to the SAR control level of 10 W/kg per International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for occupational exposure (Health Physics 74 (4) 494; 1998). The field intensities were measured to determine the effectiveness of treatment delivery. Results: Altering the size and position of the arrays facilitates field intensities above the therapeutic threshold of 1 V/cm. Within the abdominal internal organs, the SAR values were generally below the ICNIRP recommended level of 10 W/kg. The maximum SAR levels did not exceed 20 W/kg. Conclusions: TTFields could be delivered at intensities above therapeutic threshold of 1 V/cm by strategizing the array size and placement. TTFields to the abdomen can be delivered to target gastrointestinal cancers without causing thermal damage to abdominal tissues. These results also indicate that TTFields delivery can be optimized in gastrointestinal cancers.

PANOVA-3: A phase III study of tumor treating fields with nabpaclitaxel and gemcitabine for front-line treatment of locally advanced pancreatic adenocarcinoma (LAPC)

TPS469

Background: Tumor Treating Fields (TTFields) are a non-invasive, regional antimitotic treatment modality, which has been approved for the treatment of patients with glioblastoma by the FDA. TTFields predominantly act by disrupting the formation of the mitotic spindle during metaphase. TTFields were effective in multiple preclinical models of pancreatic cancer. The Phase 2 PANOVA study was the first trial testing TTFields in pancreatic cancer patients, and demonstrated the safety of TTFields when combined with nab-paclitaxel and gemcitabine in both metastatic and LAPC. The Phase 3 PANOVA-3 trial (NCT03377491) is designed to test the efficacy of adding TTFields to nab-paclitaxel and gemcitabine combination in LAPC. Methods: Patients (N = 556) with unresectable, LAPC (per NCCN guidelines) will be enrolled in this prospective, randomized trial. Patients should have an ECOG score of 0-2 and no prior progression or treatment. Patients will be stratified based on their performance status and geographical region, and will be randomized 1:1 to TTFields plus nab-paclitaxel and gemcitabine or to nab-paclitaxel and gemcitabine alone. Chemotherapy will be administered at standard dose of nab-paclitaxel (125 mg/m2) and gemcitabine (1000 mg/m2 once weekly). TTFields (150kHz) will be deilvered at least 18 hours/day until local disease progression per RECIST Criteria V1.1. Follow up will be performed q8w, including a CT scan of the chest and abdomen. Following local disease progression, patients will be followed monthly for survival. Overall survival will be the primary endpoint and progression-free survival, objective response rate, rate of resectability, quality of life and toxicity will all be secondary endpoints. Sample size was calculated using a log-rank test comparing time to event in patients treated with TTFields plus chemotherapy with control patients on chemotherapy alone. PANOVA-3 is designed to detect a hazard ratio 0.75 in overall survival. Type I error is set to 0.05 (two-sided) and power to 80%. Clinical trial information: NCT03377491.

Abstract CT082: TTFields concurrent with standard of care for the treatment of stage 4 non-small cell lung cancer (NSCLC) following platinum failure: phase III LUNAR study

Tumor Treating Fields (TTFields) are a non-invasive, anti-mitotic treatment modality. TTFields disrupt the formation of the mitotic spindle, and dislocation of intracellular constituents. TTFields significantly extend the survival of newly diagnosed glioblastoma patients when combined with temozolomide. Efficacy of TTFields in NSCLC has been shown preclinically and their safety in a phase I/II pilot study with pemetrexed. We hypothesize that adding TTFields to immune checkpoint inhibitor or docetaxel following platinum doublet failure will increase OS.

Methods: Patients (N=534) with squamous or non-squamous NSCLC are enrolled in the LUNAR phase III study [NCT02973789]. Patients are stratified by their selected standard therapy (immune checkpoint inhibitors or docetaxel), histology (squamous vs. non-squamous) and geographical region. Key inclusion criteria are disease progression while on or after platinum-based systemic therapy, ECOG 0-2, no electronic medical devices in the upper torso, and absence of brain metastasis. Docetaxel or immune checkpoint inhibitors are given at standard doses. TTFields are applied to the upper torso for 18 hours/day, allowing patients to maintain daily activities. TTFields are continued until progression in the thorax and/or liver. Follow up is performed every 6 weeks, including CT scans of the chest and abdomen. On progression in the thorax and/or liver, patients have three post-progression follow up visits and are later followed monthly for survival. The primary endpoint is superiority in OS between patients treated with TTFields in combination with the standard of care treatments, compared to standard of care treatments alone. Key secondary endpoints compare the OS in patients treated with TTFields and docetaxel Vs. those treated with docetaxel alone, and patients treated with TTFields and immune checkpoint inhibitors Vs. those treated with immune checkpoint inhibitors alone. An exploratory analysis will test non-inferiority of TTFields with docetaxel compared to checkpoint inhibitors alone. Secondary endpoints include progression-free survival, radiological response rate, quality of life based on the EORTC QLQ C30 questionnaire and severity & frequency of adverse events. The sample size is powered to detect a HR of 0.75 in TTFields-treated patients versus control group.

Citation Format: Uri Weinberg, Ori Farber, Moshe Giladi, Zeev Bomzon, Eilon Kirson. TTFields concurrent with standard of care for the treatment of stage 4 non-small cell lung cancer (NSCLC) following platinum failure: phase III LUNAR study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT082.

Abstract CT157: PANOVA-3: A phase III study of TTFields with nab-paclitaxel and gemcitabine for front-line treatment of locally-advanced pancreatic adenocarcinoma (LAPC)

Tumor Treating Fields (TTFields) are a non-invasive, regional antimitotic treatment modality, which has been approved for the treatment of patients with glioblastoma by the FDA. TTFields predominantly act by disrupting the formation of the mitotic spindle during metaphase. TTFields were effective in multiple preclinical models of pancreatic cancer. The Phase 2 PANOVA study was the first trial testing TTFields in pancreatic cancer patients, and demonstrated the safety of TTFields when combined with nab-paclitaxel and gemcitabine in both metastatic and LAPC. The Phase 3 PANOVA-3 trial (NCT03377491) is designed to test the efficacy of adding TTFields to nab-paclitaxel and gemcitabine combination in LAPC.

Trial Design: Patients (N=556) with unresectable, LAPC (per NCCN guidelines) will be enrolled in this prospective, randomized trial. Patients should have an ECOG score of 0-2 and no prior progression or treatment. Patients will be stratified based on their performance status and geographical region, and will be randomized 1:1 to TTFields plus nab-paclitaxel and gemcitabine or to nab-paclitaxel and gemcitabine alone. Chemotherapy will be administered at standard dose of nab-paclitaxel (125 mg/m2) and gemcitabine (1000 mg/m2 once weekly). TTFields (150kHz) will be deilvered at least 18 hours/day until local disease progression per RECIST Criteria V1.1. Follow up will be performed q8w, including a CT scan of the chest and abdomen. Following local disease progression, patients will be followed monthly for survival. Overall survival will be the primary endpoint and progression-free survival, objective response rate, rate of resectability, quality of life and toxicity will all be secondary endpoints. Sample size was calculated using a log-rank test comparing time to event in patients treated with TTFields plus chemotherapy with control patients on chemotherapy alone. PANOVA-3 is designed to detect a hazard ratio 0.75 in overall survival. Type I error is set to 0.05 (two-sided) and power to 80%.

Citation Format: Uri Weinberg, Ori Farber, Moshe Giladi, Zeev Bomzon, Gitit Lavy-Shahaf, Eilon D. Kirson. PANOVA-3: A phase III study of TTFields with nab-paclitaxel and gemcitabine for front-line treatment of locally-advanced pancreatic adenocarcinoma (LAPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT157.