乌鸦传媒

Topical cantharidin (Ycanth) was approved as the first treatment specifically for molluscum contagiosum, the .

Molluscum contagiosum is a viral skin infection that affects as many as 6 million Americans, mostly children. The approval is to treat adults and pediatric patients as young as 2 years.

The new treatment consists of a single-use applicator containing a premeasured dose of cantharidin, Verrica Pharmaceuticals. It is administered by a healthcare provider and applied to affected areas every 3 weeks, as needed.

Principal support for the approval came from two phase III, randomized, vehicle-controlled clinical trials, and , that involved a total of 528 people ages 2 years and older with documented molluscum infection. Both trials met the primary endpoint of complete clearance of all molluscum lesions by day 84. Cantharidin met the endpoint in 46% and 54% of patients in the two trials, compared with 18% and 13% with placebo (P<0.0001).

No serious adverse reactions occurred in either trial. Adverse reactions were primarily mild or moderate in nature, and 2.3% of patients treated with cantharidin discontinued because of adverse events (AEs), as compared with 0.5% among patients allocated to vehicle. According to the FDA, the most common AEs with cantharidin occurred at the application site (blistering, pain, itching, scabbing, reddening, discoloration, dryness, edema, skin erosion).

The warns that "life threatening or fatal toxicities can occur if administered orally," and notes the potential for eye toxicity if contact is made after treatment. The product is also flammable, even after drying.

When the initial results were reported at the American Academy of Dermatology meeting in 2019, dermatologists expressed enthusiasm for the possibility of an effective, condition-specific therapy for molluscum.

The approval follows a against use of unapproved treatments for molluscum contagiosum.

"It's likely that unapproved products marketed to treat molluscum do not do what they claim, and the ingredients in them could cause adverse effects," the agency stated. "The FDA has received reports of side effects in children and adults associated with some of these products, including skin reddening, abrasion from skin scratching, and permanent scarring."

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