GENEVA – For patients with malignant pleural mesothelioma, adding tumor-treating fields (TTFields) to standard pemetrexed plus platinum compound chemotherapy could boost median overall survival by about 6 months, according to final results from the phase 2 STELLAR trial.
The survival benefit of TTFields was greatest among patients with epithelioid mesothelioma, reported lead author, of Humanitas Gavazzeni in Bergamo, Italy. According to Dr. Ceresoli, who presented findings at the at the European Lung Cancer Conference, TTFields offer a safe way to improve mesothelioma outcomes without increasing the risk of serious adverse events.
“TTFields are a locoregional treatment comprising low-intensity alternating electric fields delivered through a portable medical device,” Dr. Ceresoli explained at the meeting, presented by the European Society for Medical Oncology. “Their main mode of action is an anti-mitotic mechanism.” He noted that TTFields are already approved by the Food and Drug Administration for newly diagnosed glioblastoma.
The STELLAR trial involved 80 patients with mesothelioma who were treated with TTFields in combination with standard first-line chemotherapy, a combination of pemetrexed with cisplatin or carboplatin. Patients were instructed to self-administer continuous 150 kHz TTFields for at least 18 hours a day. Eligibility required an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1. Both ECOG status and cancer-related pain were followed with a visual analog scale until disease progression. Median overall survival (OS) was the primary endpoint.
The patient population was predominantly male (84%), with median age of 67 years. About 44% of the patients had an ECOG performance status of 1 and 66% had epithelioid histology. Median treatment time per day was 16.3 hours.
After a minimum follow-up of 1 year, patients treated with TTFields in combination with standard chemotherapy had a median overall survival of 18.2 months, compared with 12.1 months for standard chemotherapy alone, which Dr. Ceresoli cited as the historical benchmark. The survival benefit was 3 months longer among patients with epithelioid mesothelioma, who had a median overall survival of 21.2 months.
In addition to survival benefits, the investigators found that median time to decreased performance status was just over 1 year (13.1 months), and that pain did not increase to a clinically significant degree (33%) until an average of 8.4 months. Although no device-related serious adverse events occurred, 37 patients (46%) experienced TTFields-related dermatitis; 4 of these patients had grade 3 dermatitis. Dr. Ceresoli noted that dermatitis was typically “easily managed” with topical application of a corticosteroid, while patients with severe dermatitis took short treatment breaks.
“In conclusion, in the STELLAR trial, TTFields in combination with standard chemotherapy were effective and safe for first-line treatment of unresectable malignant pleural mesothelioma, and median overall survival was significantly longer as compared to historical controls,” Dr. Ceresoli said, pointing out better survival than in recent trials MAPS and LUME-Meso.
When asked by the invited discussant about future research, Dr. Ceresoli described a narrower focus for upcoming TTFields studies for mesothelioma. “As you well know, most patients have epithelioid histology, and in our hands, the patients with epithelioid histology had better prognoses,” he said. “So, in the future, I think we will focus on epithelioid tumors.”
Dr. Ceresoli disclosed travel funding from Novocure.
SOURCE: Ceresoli et al. ELCC 2019. Abstract 55O.