New Long-term Data for Tumor-Treating Fields in Glioblastoma
Insights From: Maciej Mrugala, MD, PhD, MPH, University of Washington Medical Center; Suriya Jeyapalan, MD, MPH, Tufts Medical Center; Daniela Bota, MD, UC Irvine Medical Center
Daniela Bota, MD: At the Society for Neuro-Oncology Meeting this year, we have a new report on the long-term data for the EF-14 study. And the EF-14 study was the study that was instrumental to the Optune approval for newly diagnosed glioblastoma patients. The way the study was designed was as a randomized study, where 695 patients were allowed to complete the radiation on the Temodar (temozolomide) alone. Then they were randomized 2:1 to receive the combination of Optune and temozolomide, followed by, at recurrence, whatever was the best treatment their oncologist chose, in addition to the Optune, which was continued for up to 3 years. The other group of patients was treated with standard-of-care treatment, which was temozolomide followed by whatever treatment was considered to be the best by the oncologist.
The EF-14 study had 2 major endpoints. The primary endpoint was progression-free survival, and the secondary endpoint was overall survival. For the progression-free survival, the determinations were made by independent radiologists that were blinded to the assignment of the patients to each treatment group. The results showed that the patients that received Optune in combination with Temodar had the progression-free survival, from randomization, of 6.7 months, as compared to 4 months in the group that received temozolomide alone. For the overall survival and the combination group, a median overall survival was 21 months compared to only 16 months in the group that received the standard of care without the Optune. Those data are very, very similar with the previously published data on the interim analysis, which makes us even more confident that the treatment is working as it is supposed to be working.
I think the most important point that I also want to highlight is that the use of Optune in this study increased the number of people that have become long-term survivors. So, if we look at 2-year survival, the percentage of people that lived at 2 years for the combination group was 43% compared to 30% in the group that was treated with the standard of care. Even more important and rewarding for us is that at 4 years, the number of patients that survived in the combination group was 17% as compared to only 10% in the group that received the standard-of-care treatment.
So, when we talk about the safety profiles on the EF-14 study, we have to remember that every patient in the study got radiation, got temozolomide, and at progression, got more surgery or more radiation and other chemotherapy drugs based on the oncologist’s preference. It comes as no surprise for us that the side effects on the 2 groups are very similar, because we see side effects that we always have seen with chemotherapy agents such as temozolomide. We see some nausea, we see some decreased platelet counts and white blood cell count, and we see seizures and depression, which is very common for the patients, unfortunately, with brain tumors. And equally distributed between the 2 groups, we see headaches. What is different for the group that received Optune is that there is a small number of device-related side effects, which all of them are local. This device is composed of electrodes that get applied on the scalp. We can see some mild inflammation, some mild erosion at the level of the electrical device.
The other things that we have seen a little bit more are problems with falling, and this is related to the fact that the device has a cord. Some of the patients can also when they’re home, instead of using the battery, plug it to the wall. So, we want to be very careful to let the patients know that they have to pay attention where there is space and make sure that they don’t fall and institute safe fall precautions.
Suriya Jeyapalan, MD, MPH: The EF-14 trial, I do have a very special place in my heart for this because I think everybody who is an oncologist would like to participate in a trial that makes a difference in our patients. And I have to say, I have a tremendous gratitude to Dr. Stupp and the company and to Tufts Medical Center for having opened up the trial as well, for me being able to participate in it. Because it really has been the single biggest advance in the last decade in the treatment of these patients.
And I want to just talk about a little bit about the misconceptions that are out there, and I think these are coming from people that didn’t participate in the trial. It’s also, at an almost innate sense, like, how the heck is this going to work? I have to say, I was one of those doctors myself. I was like, “Oh, this sounds like a crazy idea. They’re going to send people around with this little cap on their head and hook them up to a battery and hope this cures GBMs, which is such a deadly disease.” I was wrong. And when I look at the data, it’s amazing to me how wrong I was, and I’m so glad to be wrong, because everybody wants all these trials to work. I’m glad this one works.
Other things that I’ve also heard about the trial was that people are confused about how the trial was designed. It was a very simple 2:1 randomization trial. It was basically two-thirds of the patient got the device with Temodar and radiation, and one-third just got the Temodar and radiation. The other thing I think people also are maybe misunderstanding, too, is that people were matched based on performance status, surgical resection, MGMT methylation—all the things that we know are prognostic indicators. So, I think it was a very fairly done trial. I think it was in a large population of patients, and they proved it. And we’re all scientists, and we should take a look at these data very carefully. It’s published in JAMA; it’s out there. They’ll publish the final analysis, I’m sure, in another journal here pretty soon. But realize that it really has very little side effects except for the skin reaction. It doesn’t cause your blood count to drop. It doesn’t cause you any nausea/vomiting, and it could be easily combined with other treatment modalities without any detriment to the patient. I think it should be offered to everybody.
Daniela Bota, MD: In my opinion, this is, without any doubt, the standard of care. It is included in the NCCN guidelines. It is an FDA-approved treatment, and it’s making a major impact on the patient’s survival. Let’s just look at the 4-year data: going from a 10% to 17% survival rate, it’s a significant step. It’s almost doubling in the number of patients that get to celebrate 4 years after their original diagnosis. Going back to what we talked before, the addition of Temodar gave us 2 months in the original study. So, I think that this should be incorporated in the practice. I think that we should all work with the patients. It’s, in the end, the patient’s decision. But I think the decision has to be made with the patient fully understanding that this is, right now, the most promising FDA-approved treatment that we have had for a while.