A new non-invasive device that uses alternating electrical fields to blast brain tumors and kill cancer cells before they can multiply has received the backing of a US Food and Drug Administration (FDA) panel, although two panel members abstained from voting because of concerns that while trials showed the device was safe, it did not appear to be effective.
The main argument in support of the device appears to be that it offers patients a higher quality of life, and is not necessarily about longer survival, where its effect appears to be minimal.
Patients who attended the panel hearing last week urged members to recommend FDA approval.
The Neurological Devices Panel of the Medical Devices Advisory Committee to the FDA held its hearing on 17 and 18 March in Gaithersburg, Maryland, to provide advice and recommendations concerning the NovoTTF-100A Treatment Kit (TTF stands for for tumor treating fields).
The device, which is portable, is carried in a shoulderbag and can be worn continuously; it uses non-invasive technology and is developed by Novocure Ltd, a subsidiary of Standen Ltd with operations in Portsmouth, New Hampshire in the US and a research center in Haifa, Israel.
Briefing notes for the committee note that the pre-market application for the device describes its intended use as a monotherapy after other surgery and radiation options have been exhausted, in place of standard therapy for histologically- or radiologically- confirmed glioblastoma multiforme (GBM) in adults (21 years and above).
The device deilivers very low intensity alternating electrical fields generated by special insulated electrodes applied to the surface of the skin on the scalp.
Because of the unique shape of cancer cells when they are about to divide, the TTFields generate forces inside the cells that cause various cell components to pile up and become displaced in such a way that they fall apart, effectively preventing cell division and eventually causing cell death.
Data from a trial suggests that the fields affect healthy brain cells much less than cancer cells because they multiply at a much slower rate, if at all.
Glioblastoma is one of the most lethal forms of brain cancer and most patients don’t survive more than five years after diagnosis.
It is very difficult to treat. The usual treatment is surgical removal of as much of the tumor as possible, followed by radiation and chemotherapy. Many patients also take Avastin, a drug that stops the growth of blood vessels that feed the tumor.
According to a report in the Wall Street Journal, the FDA panel voted 7 to 3 in favor of a question as to whether the benefits of the device outweighed the risks, and two members abstained. The panel was split on whether the product was effective, although it agreed unanimously that it was safe.
It seems likely that such a majority vote means the FDA will approve the device for use in the US; although the agency is not bound to follow the recommendation of its advisory committees, it usually does.
One panel member, Sarah Hollingsworth Lisanby, a brain-stimulation expert who chairs the psychiatry department at Duke University, abstained because she was not convinced the clinical trial report the company submitted showed the device was effective, although she said the technology “could be a real breakthrough”, reported the Wall Street Journal.
The FDA panel reviewed a report of a trial involving 237 patients in Europe, the US and Israel, who had advanced brain cancer and had already received standard treatments when they enrolled.
Half the patients were asked to connect the device and wear it for 20 hours a day. The other half did not use the device, they received standard chemotherapy treatments.
Most of the patients in both groups died within six months, a few survived a bit longer.
But the FDA said the data on the US patients showed a slight trend toward longer survival.
A phase II study of the device is already under way for patients with locally advanced and metastatic non-small cell lung-cancer (NSCLC) who have failed prior treatments with chemotherapy.
The device has received its CE Mark and is approved for sale in six European countries as a treatment for glioblastoma.
The FDA is expected to make a ruling in the next three months.
— More info on the trial, science and studies from novocuretrial.com
Sources: Wall Street Journal (17 Mar 2011), Novocure, PRNewswire (10 Oct 2010).
Written by: Catharine Paddock, PhD