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Applications for laser-assisted drug delivery on the horizon, expert says



For those who view fractional ablative laser–assisted drug delivery as a pie-in-the-sky procedure that will take years to work its way into routine clinical practice, think again.

Dr. Merete Haedersdal, professor of dermatology, University of Copengahen

Dr. Merete Haedersdal

According to Merete Haedersdal, MD, PhD, DMSc, fractional ablative laser–assisted drug delivery is now ready to be incorporated into daily practice for the treatment of actinic keratoses (AKs) and scars, which is off-label use.

“The groundwork has been established over a decade with more than 100 publications available on PubMed,” Dr. Haedersdal, professor of dermatology at the University of Copenhagen, said during a virtual course on laser and aesthetic skin therapy. “There is no doubt that by drilling tiny little holes or channels with ablative fractional lasers, we enhance drug delivery to the skin, and we also empower different topical treatment regimens. Also, laser-assisted drug delivery holds the potential to bring new innovations into established medicine.”

Many studies have demonstrated that clinicians can enhance drug uptake into the skin with the fractional 10,600 nm CO2 laser, the fractional 2,940 nm erbium:YAG laser, and the 1,927 nm thulium laser, but proper tuning of the devices is key. The lower the density, the better, Dr. Haedersdal said.

“Typically, we use 5% density or 5% coverage, sometimes 10%-15%, but don’t go higher in order to avoid the risk of having a systemic uptake,” she said during the meeting, which was sponsored by Harvard Medical School, Massachusetts General Hospital, and the Wellman Center for Photomedicine. “Also, the pulse energy for channel depth needs to be tailored to the specific dermatologic disease being treated,” she said, noting that for melasma, for example, “very low pulse energies” would be used, but they would be higher for treating thicker lesions, such as a hypertrophic scar.

Treatment with ablative fractional lasers enhances drug accumulation in the skin of any drug or substance applied to the skin, and clinical indications are expanding rapidly. Established indications include combining ablative fractional lasers and photodynamic therapy (PDT) for AKs and combining ablative fractional lasers and triamcinolone or 5-FU for scars. “Although we have a good body of evidence, particularly for AKs, it’s still an off-label use,” she emphasized.

Evolving indications include concomitant use of ablative fractional laser and vitamins and cosmeceuticals for rejuvenation; lidocaine for local anesthetics; tranexamic acid and hydroquinone for melasma; antifungals for onychomycosis; Botox for hyperhidrosis; minoxidil for alopecia; and betamethasone for vitiligo. A promising treatment for skin cancer “on the horizon,” she said, is the “combination of ablative fractional laser with PD1 inhibitors and chemotherapy.”

Data on AKs

Evidence supporting laser-assisted drug delivery for AKs comes from more than 10 randomized, controlled trials in the dermatology literature involving 400-plus immunocompetent and immunosuppressed patients. These trials have found ablative fractional laser–assisted PDT to be significantly more efficacious than PDT alone up to 12 months postoperatively and to foster lower rates of AK recurrence.

In a meta-analysis and systematic review, German researchers concluded that PDT combined with ablative laser treatment for AKs is more efficient but not more painful than either therapy alone. They recommended the combined regimen for patients with severe photodamage, field cancerization, and multiple AKs.

In 2020, an international consensus panel of experts, including Dr. Haedersdal, published recommendations regarding laser treatment of traumatic scars and contractures. The panel members determined that laser-assisted delivery of corticosteroids and antimetabolites was recommended for hypertrophic scars and cited triamcinolone acetonide suspension (TAC) as the most common corticosteroid used in combination with ablative fractional lasers. “It can be applied in concentrations of 40 mg/mL or less depending on the degree of hypertrophy,” they wrote.

In addition, they stated that 5-FU solution is “most commonly applied in a concentration of 50 mg/mL alone, or mixed with TAC in ratios of 9:1 or 3:1.”

According to the best available evidence, the clinical approach for hypertrophic scars supports combination treatment with ablative fractional laser and triamcinolone acetonide either alone or in combination with 5-FU. For atrophic scars, laser-assisted delivery of poly-L-lactic acid has been shown to be efficient. “Both of these treatments improve texture and thickness but also dyschromia and scar functionality,” said Dr. Haedersdal, who is also a visiting scientist at the Wellman Center for Photomedicine, Boston.

Commenting on patient safety with laser-assisted drug delivery, “the combination of lasers and topicals can be a powerful cocktail,” she said. “You can expect intensified local skin reactions. When treating larger areas, consider the risk of systemic absorption and the risk of potential toxicity. There is also the potential for infection with pathogens such as Staphylococcus aureus. The take-home message here is that you should only use the type and amount of drug no higher than administered during intradermal injection.”

Dr. Haedersdal disclosed that she has received equipment from Cherry Imaging, Cynosure-Hologic, MiraDry, and PerfAction Technologies. She has also received research grants from Leo Pharma, Lutronic, Mirai Medical, Novoxel, and Venus Concept.

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