Can Cantharidin cause application site vesicles?

ADVERSE REACTIONS The following adverse reactions are described elsewhere in the labeling: Local Skin Reactions [see Warnings and Precautions (5.2) ] Most common (incidence ≥1%) adverse reactions are the following local skin reactions at the application site: vesiculation, pain, pruritus, scabbing, erythema, discoloration, application site dryness, edema, and erosion. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Verrica Pharmaceuticals Inc. at 1-877-837-7422 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Local skin reactions are expected and should be reported if they are severe. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. YCANTH was studied in two randomized, double-blind, placebo-controlled phase 3 trials, Trial 1 (NCT03377790) and Trial 2 (NCT03377803) (n = 266, and n = 262, respectively) in subjects with molluscum contagiosum. Most patients received a single 24-hour dermal administration of YCANTH or vehicle for each lesion every 3 weeks for up to 4 treatments. YCANTH Solution or vehicle were removed prior to the 24-hour timepoint in 109/311 (35%) subjects treated with YCANTH Solution and 46/216 (21%) subjects treated with vehicle due to treatment-emergent adverse events. Table 1 presents the percentage of subjects with selected adverse reactions (incidence ≥ 1%) by the most severe grade reported during Trial 1 and Trial 2. Adverse reactions were primarily local skin reactions at the application site. Local skin reactions at the application site were observed in 97% of subjects treated with YCANTH during both trials. Table 1. Percentage of Subjects with Selected Adverse Reactions (Incidence ≥1%) by Severity in Trial 1 and Trial 2 (Safety Population) YCANTH N=311 Vehicle N=216 Preferred Term Name Mild Moderate Severe Mild Moderate Severe Application site vesicles 60% 32% 4% 27% 2% 0% Application site pain and pain 41% 20% 2% 16% 1% 0% Application site pruritus and pruritus 47% 8% 1% 30% 7% 0% Application site scab and scab 39% 9% 0% 20% 1% 0% Application site erythema and erythema 24% 21% <1% 20% 7% 0% Application site discoloration 28% 4% <1% 12% 1% 0% Application site dryness 19% 2% 0% 14% 1% 0% Application site edema 7% 3% 0% 3% 1% 0% Application site erosion 6% 1% 0% 1% 0% 0% Contact dermatitis 0% 1% 0% 0% 0% 0% There were no serious adverse reactions reported in the two controlled trials. The discontinuation rate due to an adverse reaction was 2.3% among subjects treated with YCANTH and 0.5% among subjects treated with vehicle.

WARNINGS AND PRECAUTIONS Toxicities Associated with Inappropriate Administration: Life threatening or fatal toxicities can occur if administered orally. Avoid contact with the treatment area, including oral contact, after treatment. Ocular toxicity can occur if YCANTH comes in contact with eyes. If YCANTH gets in eyes, flush eyes with water for at least 15 minutes. ( 5.1 ) Local Skin Reactions : Reactions at the application site have included vesiculation, pruritus, pain, discoloration, and erythema. Avoid application near eyes and mucosal tissue, and to healthy skin. If YCANTH contacts any unintended surface, or healthy skin, immediately remove. If severe local skin reactions occur, remove prior to 24 hours after treatment. ( 5.2 ) Flammability : YCANTH is flammable, even after drying. Avoid fire, flame or smoking near lesion(s) during treatment and after application until removed. ( 5.3 ) 5.1 Toxicities Associated with Inappropriate Administration YCANTH is for topical use only. YCANTH is not for oral, mucosal, or ophthalmic use. Life threatening or fatal toxicities can occur if YCANTH is administered orally [see Overdosage (10) ]. Adverse reactions to oral ingestion of cantharidin have included renal failure, blistering and severe damage to the gastrointestinal tract, coagulopathy, seizures, and flaccid paralysis. Advise patients and/or caregivers to avoid oral contact and to avoid touching lesions after YCANTH treatment and to seek medical attention immediately if YCANTH is accidently ingested. Ocular toxicity can occur if YCANTH comes in contact with the eyes. Adverse reactions from contact of YCANTH with the eyes can include corneal necrosis, ocular perforation, and deep ocular injuries. Do not apply YCANTH near or to the eyes. If YCANTH comes in contact with the eyes, flush eyes with water for at least 15 minutes and seek medical attention immediately. 5.2 Local Skin Reactions YCANTH is a vesicant. Local skin reactions at the application site were observed in 97% of subjects treated with YCANTH during clinical trials. Local skin reactions included vesiculation, pruritus, pain, discoloration, and erythema [see Adverse Reactions (6.1) ] . Avoid application near the eyes and mucosal tissues, and to adjacent healthy skin. If YCANTH contacts any unintended surface, including healthy skin, immediately remove by wiping with a cotton swab or gauze . Avoid other topical products (e.g. creams, lotions, or sunscreen) 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. If severe blistering, severe pain or other severe adverse reactions occur, remove YCANTH prior to the recommended 24 hours after administration by washing with soap and water . 5.3 Flammability YCANTH is a flammable liquid, even after drying. Avoid fire, flame or smoking near lesion(s) during treatment and after application until removed.