The Food and Drug Administration said Wednesday that an experimental implantable device for epilepsy developed by Medtronic (MDT) failed to meet its primary goal of statistically reducing the number of seizures in patients. 

The statement came as part of materials the FDA released late Tuesday ahead of meeting of the agency's Neurological Devices Panel. 

Medtronic's device, which is already used in patients with Parkinson's and patients with severe obsessive-compulsive disorder, is a pacemaker-like device implanted into a patient's chest that delivers electrical impulses into a patient's brain. 

The therapy, called "deep-brain stimulation," was being considered for epilepsy sufferers who were unresponsive to anticonvulsant medications. The study looked at 110 patients who weren't helped by at least three drugs.

In its summary for the panel, the FDA said that the device provided "no statistically significant differences" in seizure-free days during the 90-day blinded phase of the study. Patients, both using an active device and a placebo, both recorded an average of 3.3 seizures a month. 

Both the control group and the active group had devices implanted but only the active group had the device turned on.

However, there was some reduction in the number of seizures for patients during a longer-term un-blinded study, which is the benchmark that Medtronic wishes the panel to use when determining its effectiveness. 

Medtronic is also asking the FDA to exclude results from one patient, which the company says skews the results. 

The FDA's panel will weigh Medtronic's request and the results when the neurological committee, which consists of non-FDA doctors and experts, meets on Friday.

Shares of Medtronic were down 0.1% to $44.69 on Wednesday.