FDA draft guidance covers low-level light therapy devices

The US Food and Drug Administration (FDA) has published a draft guidance for low-level light therapy (LLLT) devices, or photobiomodulation (PBM) devices, which are typically used for aesthetic or dermatologic uses, such as to treat cold sores. While some light-emitting products pose low risks to users and fall under the agency’s general wellness devices policy, others can pose a high enough risk to users for the agency to consider them regulated medical devices.
 
FDA published a guidance on submitting 510(k) applications for photobiomodulation (PBM) devices, also known as LLLTs. The products deliver non-heating doses of light energy to patients, often for aesthetic and dermatological procedures. Similar to other light therapy products, PBM devices use coherent light sources, also known as lasers; non-coherent light sources, such as light-emitting diodes (LED); or a combination of the two types of light sources. However, unlike other types of products, they typically don’t come with the same level of risk.
 
“PBM therapy is provided at a much lower fluence and irradiance compared to ablative or coagulating light devices such as those using high power lasers or intense pulsed light (IPL) sources,” FDA clarifies in the guidance. “The mechanism of actions for PBM for different clinical indications is not fully understood. Outcomes are dependent on many factors such as wavelength of light, fluence, irradiance, pulsing parameters, and beam spot size.”
 
FDA lists seven types of class II PBM products in the guidance that may fall within its regulatory purview where sponsors would need to submit a premarket application to clear them for market. They include certain laser surgical instruments, devices to reduce wrinkles and fat, treat cold sores and non-thermal devices to help treat pain.
 
The agency notes that products that contain PBM components, such as those for electrostimulation, mechanical massaging and ultrasound, may also require a premarket application. However, light-emitting devices that are only meant to be used as general wellness products and present a low-level risk to users are not considered within the scope of the draft guidance.

The guidance addresses several issues such as what to consider when submitting a premarket submission for a PBM product.
 
One key area the guidance covers is how sponsors can sufficiently compare the sponsors new product to the predicate product in the 510(k) application.
 
Generally, when a 510(k) is submitted, the sponsor must describe how a product is similar and different from the predicate product. To address the issue, the guidance includes a sample table of what characteristics the sponsor should look at when comparing the products.
 
The guidance also makes recommendations on providing reprocessing instructions and how the sponsor should present the limitations and safety profile of the PBM device in its labeling. FDA notes, however, that if the device is not meant to be used by a layperson, it doesn’t need to have directions specifically targeting laypeople, though it does need to have adequate information for health care providers to be able to use the product properly.
 
The guidance also addresses biocompatibility for such devices.
In recent years, FDA has put more emphasis on identifying potential biocompatibility issues with medical devices. In the draft guidance, the agency asks PBM device sponsors to either provide biocompatibility data from the predicate device or additional data to show they’ve done their due diligence to identify potential biocompatibility issues.
 
“You should determine the biocompatibility of all patient-contacting materials present in your device,” said FDA. “If your device is identical in composition and processing methods to a PBM device with a history of successful use, you may reference previous testing experience or the literature, if appropriate. For some device materials, it may be appropriate to provide a reference to either a recognized consensus standard, or to a Letter of Authorization (LOA) for a device Master File (MAF).”
 
“If you are unable to identify a legally marketed predicate device with similar location/duration of contact and intended use that uses the same materials as used in your device, we recommend you conduct and provide a biocompatibility risk assessment,” the agency added. “The assessment should explain the relationship between the identified biocompatibility risks, the information available to mitigate the identified risks, and identify any knowledge gaps that remain. You should then identify any biocompatibility testing or other evaluations that were conducted to mitigate any remaining risks.”
 
The guidance touches on other topics sponsors should consider in their premarket submissions, including software performance, usability studies, electrical and thermal safety and clinical performance testing.
 
While FDA addresses a broad range of PBM devices in the guidance, the agency puts a significant amount of emphasis on devices used to treat cold sores.
 
For instance, the guidance notes that labeling for cold sore devices must direct end-users to contact the manufacturer and MedWatch, FDA’s adverse events reporting system, if they experience any adverse events. It must also include information specific to the intended patient population and treatment regimen. When reprocessing cold sore PBM devices, the agency notes that the cleaning and disinfection instructions for the devices need to be validated before reuse.
 
Generally, FDA recommends that over-the-counter PBM devices should perform three usability studies including to demonstrate lay users are able to correctly identify that they are the intended patient population, are able to correctly and safely use the product, and understand the limitations of the product from the labeling. The agency recommends that PBM devices used to treat cold sores go one step further.
 
“Note that for cold sore devices, simulated use testing must include information from a usability, label comprehension and self-selection study to demonstrate that the device can be used by the intended patient population without any assistance,” the guidance states.
 
Stakeholders can comment on the draft guidance on www.regualtions.gov under docket no. FDA-2022-D-3116 until 13 March.