Birch Triterpenes

FILSUVEZ is indicated for the treatment of wounds associated with dystrophic and junctional epidermolysis bullosa (EB) in adult and pediatric patients 6 months of age and older. FILSUVEZ topical gel is indicated for the treatment of wounds associated with dystrophic and junctional epidermolysis bullosa in adult and pediatric patients 6 months of age and older. ( 1 )

Topical gel: 10% birch triterpenes w/w in a colorless to slightly yellowish, opalescent, non-aqueous gel supplied in 25 mL sterile tubes. Topical gel: 10% birch triterpenes w/w supplied in 25 mL sterile tubes ( 3 )

None. None ( 4 )

Hypersensitivity Reactions : If signs or symptoms of hypersensitivity occur, discontinue use immediately and initiate appropriate therapy. ( 5.1 )

5.1 Hypersensitivity Reactions Local hypersensitivity and skin reactions have been reported in patients treated with FILSUVEZ, including urticaria and dermatitis. If signs and symptoms of local or systemic hypersensitivity occur, discontinue FILSUVEZ immediately and initiate appropriate therapy.

The following clinically significant adverse reactions are discussed elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] The most common (incidence ≥2%) adverse reactions are application site reactions. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Chiesi USA Inc. at 1-888-661-9260 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

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. The safety of FILSUVEZ was evaluated in EASE, a randomized, double-blind, multicenter, placebo-controlled trial in 223 adult and pediatric subjects with inherited EB. During the double-blind phase of EASE, subjects received topical treatment with either FILSUVEZ or a placebo gel on partial-thickness wounds every 1 to 4 days for a total of 90 days. Treated wounds were covered with non-adhesive dressings. Following completion of the double-blind phase, all subjects received FILSUVEZ for a total of 24 months during the open-label phase [see Clinical Studies (14) ] . Table 1 presents adverse reactions that occurred in at least 2% of subjects treated with FILSUVEZ during the 90-day double-blind phase of EASE and at a greater frequency than in the placebo gel group. Table 1: Number (%) of Subjects with Adverse Reactions Occurring in ≥ 2% Adverse Reaction FILSUVEZ (N=109) n (%) Placebo Gel (N=114) n (%) Application site reaction Includes: application site pruritus, administration site pain, administration site pruritus. 8 (7.3) 7 (6.1) Squamous cell carcinoma of the skin (SCC) was reported as an adverse event in the double-blind and open-label periods of EASE. Four subjects with recessive dystrophic EB each reported one SCC: a 20-year-old male on day 1 of the double-blind period; three female subjects ages 22, 46, and 49 years during the open-label period. Two of the four subjects had applied FILSUVEZ to the area which developed the SCC.

8.1 Pregnancy Risk Summary There are no available data with use of FILSUVEZ in pregnant women to evaluate for drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In an animal reproduction study, oral administration of birch triterpenes to pregnant rats during the period of organogenesis had no effects on reproductive or fetal parameters (see Data ) . Systemic absorption of FILSUVEZ in humans is low following topical administration of FILSUVEZ, and maternal use is not expected to result in fetal exposure to the drug [see Pharmacokinetics (12.3) ] . The background risk of major birth defects and miscarriage for the indicated population is unknown . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data In an embryofetal development study, birch triterpenes were orally administered to pregnant rats at doses of 10, 30, or 100 mg/kg/day during the period of organogenesis. Birch triterpenes did not cause maternal toxicity or fetal malformations at doses up to 100 mg/kg/day. In a prenatal and postnatal development study, birch triterpenes were orally administered to pregnant rats at doses of 10, 30, or 100 mg/kg/day from gestation day 5 through lactation day 20. Birch triterpenes did not affect development at doses up to 100 mg/kg/day. The available data do not support relevant comparisons of systemic birch triterpenes exposures achieved in the animal studies to exposures observed in humans after topical use of FILSUVEZ.

8.2 Lactation Risk Summary There are no data on the presence of birch triterpenes or metabolites in human milk, the effects on the breastfed infant, or the effect on milk production. No effects on the breastfed infant are anticipated since the systemic exposure of the breastfeeding woman to FILSUVEZ would be low. Therefore, the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for FILSUVEZ and any potential adverse effects on the breastfed infant from FILSUVEZ or from the underlying maternal condition [see Pharmacokinetics (12.3) ].

8.4 Pediatric Use The safety and effectiveness of FILSUVEZ for the treatment of wounds associated with dystrophic and junctional EB have been established in pediatric patients 6 months of age and older. Use of FILSUVEZ in this age group is supported by evidence from a single randomized, placebo-controlled trial in 156 subjects 6 months to 17 years of age [see Clinical Studies (14) ] . The safety and effectiveness of FILSUVEZ have not been established in pediatric patients younger than 6 months of age.

8.5 Geriatric Use Clinical studies of FILSUVEZ did not include sufficient numbers of EB subjects 65 years of age and older to determine whether they respond differently from younger subjects.

The mechanism of action of FILSUVEZ in the treatment of wounds associated with epidermolysis bullosa is unknown.