The FDA has released proposed regulations to make clear that off-label use of a device alone will not be enough to sway the agency to give its blessing to that use.

Regulators need more evidence, and the proposed guidance gives examples of direct and circumstantial evidence they would — and would not — consider in determining a safe and effective use of a device, according to FDA commissioner Stephen Hahn.

Medtech companies that seek to promote off-label uses for their devices must tread carefully, according to guidance the agency released in 2018. Off-label use may be harmful, as evidenced by a 2019 FDA warning that off-label use of Stryker‘s (NYSE:SYK) Wingspan stent system, designed to open narrowed arteries in the brain for patients with intracranial stenosis who experience repeated strokes, can increase the incidence of stroke or death.

“FDA’s longstanding position is that, in evaluating a product’s intended use, any relevant source of evidence may be considered,” Hahn said in a news release. “This longstanding position remains unchanged in the regulations being proposed today. However, the proposed revisions clarify an important point: that a firm’s knowledge that a health care provider has prescribed or used an approved or cleared medical product for an unapproved use, standing alone, is not sufficient to establish the product’s intended use. We believe that this update will provide greater certainty and predictability for regulated parties.

You can read the proposed regulations here.