Molluscum Contagiosum: Positive Results for Phase 3 Trials of Investigational Drug

Molluscum contagiosum, a highly contagious viral infection of the skin that is common in children, currently has no available treatment approved by the US Food and Drug Administration (FDA), but a new investigational drug has shown positive results in 2 phase 3 trials.

VP-102 is a propriety drug-device combination developed by Verrica Pharmaceuticals, which contains a novel topical solution of 0.7% cantharidin to treat lesions caused by the molluscum contagiosum virus, according to a statement from the company. The phase 3 program comprised 2 identical, randomized, double-blind, multicenter trials—CAMP-1 and CAMP-2—wherein a total of 528 subjects aged 2 years and older were randomized to receive either the vaccine or placebo.

The primary outcome was complete clearance of molluscum lesions over a period of 12 weeks.

“Results from CAMP-1 and CAMP-2 showed 46% and 54% of subjects treated with VP-102, respectively, achieved complete clearance of all treatable molluscum lesions at day 84 versus 18% and 13% of subjects in the placebo groups (P<.0001),” the investigators reported. “By the end of the trials (Day 84), VP-102 treated subjects had a 69% and 83% mean reduction in the number of molluscum lesions, a pre-specified endpoint, in CAMP-1 and CAMP-2, respectively, compared to 20% and 19% for subjects on placebo.”

“Molluscum are incredibly common in childhood, and can be distressing for patients and their families due to persistence, co-infection in families, irritation, and secondary bacterial infections,” Lawrence Eichenfield, MD, chief of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego and lead investigator for the VP-102 phase 3 molluscum program, told Contagion^®.

“The study results show VP-102 to be efficacious for treating molluscum, with about 50% clearance at 12 weeks, and results statistically better than vehicle. This study could lead to the first FDA-approved treatment for molluscum...many [current] treatments utilized are ineffective, painful, expensive, and without evidence basis. This medication could become a standard treatment for this skin infection,” Dr. Eichenfield continued.

Molluscum contagiosum is caused by a pox virus that has some virulence factors akin to smallpox, according to Nanette B Silverberg, MD, chief of pediatric dermatology for the Mount Sinai Health System. It results in small, raised, flesh-colored lesions with a dimple in the center. These lesions are painless, but may itch, which can lead to spreading the virus to other parts of the body or other individuals.

“Children develop molluscum through contact with infected children or fomites, with wet lesions being most contagious. Teenagers and adults who have made their sexual debut catch molluscum largely as a sexually transmitted disease,” Dr. Silverberg told Contagion^® in an interview. “In immunocompromised individuals the infection can persist indefinitely, even with therapy. Although the infection with molluscum contagiosum virus is skin deep, unlike other poxviruses, secondary complications [can] occur, including spread of lesions. Especially in those with eczema, molluscum can trigger new onset or severe flares of atopic dermatitis, contagion, itch, erythema, swelling, tenderness, pain, superinfection (bacterial), and rare occurrences such as cysts.”

Dr. Silverberg, who in 2000 published a retrospective series of 300 children whose molluscum was treated with cantharidin 0.7% in flexible collodion, was encouraged by the phase 3 results, but cautioned that physicians should know the risks associated with cantharidin before administering it.

“[T]he recently released data demonstrate good results with the proprietary product and delivery system,” she said. “The availability of the agent in an FDA-approved version as opposed to a compounded agent produced based on the cantharidin being on the bulk substance lists will enhance availability of the agent. Usage by physicians requires a good fund of knowledge of wound care as cantharidin is a phosphatase inhibitor that blisters the skin.”

Verrica plans to submit a Section 505(b)(1) New Drug Application in the second half of 2019, according to a company statement.