Five FDA-Cleared Uses, Fourteen Marketed Ones

A parent searching online for help with a child's autism symptoms will find clinic websites promising "miraculous results" from a form of transcranial magnetic stimulation sold under trade names such as MeRT and PrTMS. Nothing on those pages distinguishes a treatment the FDA has cleared from one the agency has never evaluated for that use. A letter published this fall by three senior TMS researchers lays out exactly where that line sits, and how far some clinics selling the treatment have moved past it.

What the FDA Actually Cleared

TMS devices reach the market through the FDA's 510(k) pathway, which asks a manufacturer to show that a new device is "substantially equivalent" to one already cleared – not to run a large randomized trial. Even so, each cleared indication ties to a specific coil design and a defined stimulation protocol. As of the letter's writing, the FDA has cleared TMS for treatment-resistant major depressive disorder in patients 15 and older, anxious depression in patients 22 and older, obsessive-compulsive disorder, migraine pain, and smoking cessation. The bar for "cleared" is itself uneven: the SAINT Neuromodulation System reached clearance on a small but statistically significant trial, and NeuroStar's extension to 15-year-olds rested on uncontrolled registry data rather than a controlled study. The authors place accelerated protocols close to SAINT's, and generalized anxiety or PTSD protocols backed by meta-analyses, in a middle zone they call off-label but "arguably substantiated" by the existing literature.

A Trademark Standing In for a Trial

The letter singles out one product category as furthest from that middle zone: personalized, EEG-guided TMS marketed to parents of autistic children and to autistic adults under the trade names MeRT and PrTMS. Clinic websites promise "miraculous results" and describe the treatment as "proven effective." The published evidence behind those claims, per the authors, comes down to a retrospective chart review of 28 patients co-authored by a staff member at a clinic that sells MeRT, plus one open-label trial that ran without a control group. No randomized, sham-controlled trial of either product for autism symptoms has been published. The authors do not dispute that off-label TMS can be legitimate elsewhere – they point to generalized anxiety and PTSD protocols with real trial support – but they draw a direct line between the strength of a trademark's marketing claims and the weakness of what stands behind them in this instance.

Why a Warning Letter Rarely Follows

The gap persists partly because of where U.S. law draws its enforcement boundary. Sections 331 and 352 of the Food, Drug and Cosmetic Act bar a device manufacturer from promoting an off-label use directly to the public, and the FDA has issued warning letters on that basis before. Section 396 of the same law, however, lets a licensed provider use any legally marketed device on a patient for any condition within a normal practitioner-patient relationship – which is why a clinic offering MeRT or PrTMS for autism is not, by that fact alone, breaking the law. The authors address their recommendations to providers rather than to regulators: before advertising an off-label protocol, they ask whether the promotion is lawful, whether peer-reviewed evidence supports it for this patient, whether the patient has been told the treatment is unapproved for their condition, and whether the price is reasonable given how uncertain the benefit is.