Cantharidin (Ycanth)

Number: 1051

Table Of Contents

Policy
Applicable CPT / HCPCS / ICD-10 Codes
Background
References

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Policy

Scope of Policy

This Clinical Policy Bulletin addresses cantharidin (Ycanth) for commercial medical plans. 

1. Criteria for Initial Approval

   Aetna considers FDA-approved cantharidin (Ycanth) medically necessary for the topical treatment of molluscum contagiosum when all of the following criteria are met:

   1. Member is 2 years of age or older; and
   2. Member has diagnosis of molluscum contagiosum; and
   3. Ycanth will not be used for oral, mucosal, or ophthalmic lesions; and
   4. Ycanth will be administered by a healthcare professional who has received instruction and training prior to preparation and administration of cantharidin; and 
   5. Member will not receive more than 2 applicators of cantharidin during a single treatment session (cycle).

   Aetna considers all other indications as experimental, investigational, or unproven.

2. Continuation of Therapy

   Aetna considers continuation of topical cantharidin (Ycanth) therapy medically necessary (up to a maximum of 4 treatment sessions [cycles] per infection) for treatment of molluscum contagiosum when member meets all criteria in Section I.

3. Related Policies

   1. CPB 0633 - Benign Skin Lesion Removal

Dosage and Administration

Ycanth topical solution is supplied in a sealed glass ampule contained within a single-use applicator and enclosed in a protective paperboard sleeve. Each ampule contains approximately 0.45 mL of 0.7% cantharidin solution. Each mL contains 7 mg cantharidin (0.7%). A Ycanth Break Tool is co-packaged as 2 units per each carton of applicators. Ycanth is for topical use only; not for oral, mucosal, or ophthalmic use. Ycanth is applied by a trained healthcare professional only.

Ycanth is FDA-approved as a topical treatment of molluscum contagiosum in persons 2 years of age and older. All healthcare professionals should receive instruction and training prior to preparation and administration of Ycanth.  A single application is applied directly to each lesion every 3 weeks as needed. Do not use more than 2 applicators during a single treatment session. Treated lesions are not to be covered with bandages. Persons are advised to (i) avoid other topical products on treated areas until 24 hours after treatment, and (ii) wash treatment areas with soap and water 24 hours after treatment. 

In clinical studies, persons received a maximum of 4 applications (on Days 1, 21, 42, and 63). The safety and efficacy of Ycanth use for longer than 12 weeks has not been established. 

Source: Verrica Pharmaceuticals, 2024

Experimental, Investigational, or Unproven

Aetna considers the following as experimental, investigational, or unproven because the safety and efficacy has not been established:

• More than 4 treatment sessions (cycles) of cantharidin (Ycanth) for treatment of molluscum contagiosum 
• Use for members less than 2 years of age.

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Table:

CPT Codes / HCPCS Codes / ICD-10 Codes

Code	Code Description
Other CPT codes related to the CPB:
17110	Destruction (eg, laser surgery, electrosurgery, cryosurgery, chemosurgery, surgical curettement), of benign lesions other than skin tags or cutaneous vascular proliferative lesions; up to 14 lesions
17111	15 or more lesions
HCPCS codes covered if selection criteria are met:
J7354	Cantharidin for topical administration, 0.7%, single unit dose applicator (3.2 mg)
ICD-10 codes covered if selection criteria are met:
B08.1	Molluscum contagiosum [not covered for oral, mucosal, or ophthalmic lesions]

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Background

U.S. Food and Drug Administration (FDA)-Approved Indications 

• Ycanth is indicated for the topical treatment of molluscum contagiosum in adult and pediatric patients 2 years of age and older.

Cantharidin topical solution, branded as Ycanth (Verrica Pharmaceuticals, Inc.), is a vesicant indicated for topical use only. The mechanism of action and pharmacodynamics of cantharidin in the treatment of molluscum contagiosum are unknown. However, it is thought that cantharidin topical solution works by activating serine proteases, resulting in blistering and inflammation that promote the shedding of infected cells and enhance viral clearance (Gupta et al., 2023).

There are no known contraindications for using cantharidin topical solution (Ycanth). However, Ycanth carries labeled warnings and precautions for toxicities associated with inappropriate administration, local skin reactions, and flammability. Ycanth is not for oral, mucosal (nose or genital areas), or ophthalmic use. Life threatening or fatal toxicities can occur if administered orally. Adverse reactions to oral ingestion of cantharidin have included renal failure, blistering and severe damage to the gastrointestinal tract, coagulopathy, seizures, and flaccid paralysis. Ocular toxicity can occur if Ycanth comes in contact with the eyes. Adverse reactions from contact with the eyes can include corneal necrosis, ocular perforation, and deep ocular injuries. Ycanth is not to be applied in or near the eyes. In clinical trials, local skin reactions at the application site were observed in 97% of subjects treated with Ycanth, which included vesiculation, pruritus, pain, discoloration, and erythema. Applying other topical products (e.g. creams, lotions, or sunscreen) should be avoided on treated areas until 24 hours after Ycanth treatment or until washing. Application of other topical products could spread Ycanth and cause blistering or other adverse reactions to healthy skin. Per the label, Ycanth is a flammable liquid, even after drying. Thus, patients are to avoid fire, flame or smoking near lesion(s) during treatment and after application until removed.

The most common adverse reactions (incidence of 1% or more) include the following local skin reactions at the application site: vesiculation, pain, pruritus, scabbing, erythema, discoloration, application site dryness, edema, and erosion.

There are no available data with use of Ycanth in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.

The safety and efficacy in pediatric patients below the age of 2 years have not been established. The use of Ycanth in pediatric patients is supported by results from clinical trials in patients 2 years of age and older; although the safety and efficacy of drug use for longer than 12 weeks has not been established.

Ycanth has not been studied in geriatric patients.

Molluscum Contagiosum

Molluscum contagiosum (MC) is a common, typically self-limiting, skin infection caused by a poxvirus that results in lesions, known as mollusca, that can appear anywhere on the body. Mollusca is usually asymptomatic; however, for some, the lesions may be pruritic or painful. The condition generally occurs in childhood, but can occur in healthy adolescents and adults, as well as individuals who are immunocompromised. The virus is transmitted via direct skin-to-skin contact (including sexually transmitted and participation in contact sports) or indirect contact through contaminated fomites (such as towels, underclothes, toys, razors). Additionally, the condition can spread to other parts of the body by touching or scratching a lesion and then touching another part of the body. MC typically resolves without treatment or scarring within 6 to 12 months; however, it could take as long as 4 years to disappear completely. About 10 percent of untreated patients who contract MC will experience molluscum dermatitis, which is characterized by the development of eczematous patches or plaques surrounding MC lesions.

Issues such as lesion visibility, pruritus, pain, underlying atopic dermatitis, lesions located in the genital area, concomitant bacterial infection, and the desire to prevent transmission may prompt individuals to seek treatment. However, there has been a lack of consensus regarding optimal treatment, as high-quality data on the efficacy of any treatment of MC have been limited. Treatment options have included physical removal (cryotherapy, curettage, laser), oral therapy (cimetidine), and topical therapy (compounded cantharidin, retinoids, potassium hydroxide, podophyllotoxin, imiquimod, salicylic acid).

In July 2023, the FDA approved Ycanth, topical cantharidin, for the treatment of MC in adult and pediatric patients 2 years of age and older. Ycanth is the first FDA-approved treatment for molluscum. Ycanth is a drug-in-device combination which contains a standardized formulation of pharmaceutical-grade cantharidin 0.7% in a single-use applicator for topically applied, targeted dosing and delivery. Ycanth is administered by a trained healthcare professional only. Each applicator contains enough solution to treat approximately 40 to 50 individual MC lesions, with each lesion to be treated only once by directed application per session. Treatment sessions are recommended every three weeks, with only active lesions to be treated, including any new lesions that may have developed since the previous office visit(s). The maximum recommended use per session is two applicators, which should allow for treatment of 80 to 100 MC lesions per session (Hebert et al., 2023).  Patients are instructed to wash lesions with soap and water 24 hours after treatment.

FDA approval is based on positive results from two identical phase 3 randomized, double-blind, multicenter clinical trials (CAMP-1 and CAMP-2) that showed clinically and statistically significant number of patients treated with Ycanth, compared to placebo, met the primary endpoint of complete clearance of all treatable molluscum lesions.

Cantharidin Application in Molluscum Patients (CAMP-1 and CAMP-2) trials included a total of 582 healthy participants (age ranging from 2 to 60 years) from 31 centers across the U.S.  Research clinical sites included pediatric (10/31 [32.3%]), dermatology (16/31 [51.6%]), and pediatric dermatology (4/31 [12.9%]) clinics and a research clinic (1/31 [3.2%]). Individuals with active atopic dermatitis, nonmucosal genital-area lesions, and inflamed lesions were included. Individuals who were systemically immunosuppressed, had conditions of immunosuppression, or had lesions within 10 mm of a mucosal area were excluded. MC diagnosis was made clinically, not requiring a biopsy or laboratory assessment. The participants were randomized to receive Ycanth or placebo at 21-day intervals until lesions were completely cleared or for a maximum of 4 applications. A health care professional who was blinded to the treatment group counted the number of lesions at each visit. The primary efficacy endpoint was the proportion of participants achieving complete clearance of all treated molluscum lesions by day 84. The trials met their primary endpoint which found complete lesion clearance rates of 46% (CAMP-1) and 54% (CAMP-2) with Ycanth compared to 18% (CAMP-1) and 13% (CAMP-2) with the placebo vehicle. The most common adverse events were primarily mild to moderate and included application site vesicles, pain, and pruritus. The findings of these trials support the efficacy and safety of a proprietary cantharidin-based drug-device combination for treatment of molluscum contagiosum in children and adults (Eichenfield et al., 2020).

A post-hoc analyses of the CAMP trials showed that complete clearance of all lesions was statistically significantly higher in the drug-device combination containing cantharidin 0.7% group than vehicle across all body regions, including areas deemed most sensitive. An additional post-hoc analysis demonstrated that the percentage of subjects with complete MC at the end of the trial was statistically significantly higher across all age groups for cantharidin-treated subjects compared to subjects treated with vehicle at last visit (P < .01 for each region). The incidence of pre-specified adverse events was consistent across regions. However, these analyses were post hoc, and individual lesions were not tracked for efficacy (Eichenfield et al., 2021).

A review in UpToDate on "Molluscum contagiosum" (Isaacs, 2025) includes a recommendation for the FDA-approved cantharidin 0.7% topical solution as a first-line treatment of MC (Grade 2B). 

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References