Glioblastoma brain cancer cells under microscope.
A wearable medical device that delivers tumor-treating fields (TTFields) significantly extended survival in patients with newly diagnosed glioblastoma when given in combination with standard chemotherapy.
The Optune medical device, when paired with best-known standard of care chemotherapeutic temozolomide, resulted in a median overall survival of 20.9 months versus 16 months for temozolomide alone, according to the results from a randomized phase III clinical trial presented at the American Association for Cancer Research (AACR) Annual Meeting 2017 on April 2 in Washington D.C.
These findings are noteworthy for patients with glioblastoma, an aggressive type of cancer that begins in the brain.
“Glioblastoma is the deadliest primary malignancy of the central nervous system for adults,” said lead study author Dr. Roger Stupp, a professor of Neurological Surgery at Northwestern University Feinberg School of Medicine and associate director for strategic initiatives at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, in a statement. “The last time any form of treatment was shown to improve survival for patients with this disease was more than 10 years ago, when adding temozolomide to radiotherapy was shown to improve the two-year survival rate from 10 percent to 27 percent.”
In the phase III clinical trial the research team examined 695 newly diagnosed patients with glioblastoma between July 2009 and November 2014; 466 patients were randomly assigned to receive TTFields delivered by the Optune medical device in addition to temozolomide and 229 were randomly assigned to receive maintenance temozolomide alone.
The median progression-free survival (PFS) was 6.7 months for the patients treated with TTFields and temozolomide versus 4 months for those treated with temozolomide alone.
The two, three, four and five-year survival rates significantly improved for patients who received TTFields. Patients treated with TTFields saw 43 percent two-year survival rate, 26 percent three-year survival rate, 20 percent four-year survival rate and a 13 percent five-year survival rate. The patients who only received the temozolomide saw a 31 percent two-year survival rate, a 16 percent three-year survival rate, an 8 percent four-year survival rate and a 5 percent five-year survival rate.
Overall, TTFields showed an effect in all subgroups of patients treated, including the patients who have the most unfavorable prognostic factors.
The hazard ratio for overall survival was 0.63, which means that patients randomly assigned TTFields and temozolomide had a 37 percent lower risk of death than those randomly assigned temozolomide alone.
“TTFields are an entirely new treatment modality,” Stupp said. “We need to continue to think outside the box to find other new treatments and then we need to learn how best combine them with existing treatment modalities to ensure maximum patient benefit.”
TTFields are low-intensity electric fields alternating at an intermediate frequency (200kHz) that are thought to exert anticancer effects by blocking cell division, according to Stupp.
TTFields are delivered continuously to the brain by a patient-operated, wearable medical device.
“We found that patients learned how to operate the device very quickly, often in less than an hour,” Stupp said.
Interim data from the first 315 patients enrolled in the phase III trial led U.S. Food and Drug Administration to approve the Optune medical device in 2015.
“Now we are reporting the final results for all 695 patients enrolled on the trail, including long-term outcome,” Stupp said. “Our data firmly establish the survival benefit of treatment with TTFields.”
