Birch Triterpenes

1 INDICATIONS AND USAGE 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 )

2 DOSAGE AND ADMINISTRATION Wash hands before and after applying FILSUVEZ or wear gloves for application. Apply a 1 mm layer of FILSUVEZ to the affected wound surface only. Do not rub in the gel. Cover the wound with a sterile non-adhesive wound dressing. Alternatively, apply FILSUVEZ directly to the dressing so that the topical gel is in direct contact with the wound. Apply FILSUVEZ to cleansed wounds with wound dressing changes until the wound is healed. If a FILSUVEZ-treated wound becomes infected, discontinue treatment to that wound until the infection has resolved. Each tube of FILSUVEZ is for one-time use only. Once the tube is opened, use the product immediately. Discard the tube after use in household trash or through a drug take back site, if available. Avoid contact of FILSUVEZ with eyes and mucous membranes (e.g., mouth, vagina, anus). In case of accidental contact, irrigate the area with water. FILSUVEZ is for topical use only. Not for use on mucous membranes (oral, intravaginal, or intra-anal). Not for ophthalmic use. Apply a 1 mm layer of FILSUVEZ to the affected wound surface and cover with wound dressing or apply FILSUVEZ directly to dressing so that the topical gel is in direct contact with the wound. Do not rub in the topical gel. ( 2 ) Apply FILSUVEZ at wound dressing changes until the wound is healed. ( 2 ) Each tube of FILSUVEZ is for one-time use only. ( 2 ) For topical use; not for oral, intravaginal, intra-anal, or ophthalmic use. ( 2 )

6 ADVERSE REACTIONS 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.

12.3 Pharmacokinetics Absorption Systemic exposure to betulin was assessed in the 66 evaluable subjects aged ≥13 months to ≤52 years with dystrophic and junctional EB in the clinical trial EASE using venous blood sampling and validated liquid chromatography with tandem mass spectrometry assay. Following treatment with FILSUVEZ once daily (n=27), every 2 (n=33) or 3 days (n=4) or once weekly (n=2) for 90 days with a mean treatment area of 12% body surface area or affected wound surface area of 0.11 m 2 at baseline, betulin blood concentrations in 68% subjects (n=45) were below the lower limit of quantification of 10 ng/mL on Day 90. The highest concentrations of betulin in adult and pediatric subjects with a median age of 10 years (range: ≥13 months to <18 years) were 33 ng/mL and 207 ng/mL, respectively, which were observed on Day 90. Distribution Plasma protein binding of betulin in vitro is >99.9 %. Metabolism The in vitro study indicated that incubation of 1 µmol/L betulin with human hepatocytes generated several unidentified phase I and/or phase II metabolites. In vitro, betulin was mainly metabolized by cytochrome P450 (CYP)3A. The relative contribution of CYP3A and phase II metabolizing enzymes in the overall metabolism of betulin has not been fully characterized. Drug Interaction Studies Clinical Studies No clinical studies evaluating the drug interaction potential of FILSUVEZ have been conducted. In Vitro Studies CYP Enzymes: Betulin inhibited CYP3A and CYP2C8 with an IC 50 value of >0.17 µmol/L (75 ng/mL). Betulin up to 10 µmol/L (4427 ng/mL) did not induce CYP 1A2, 2B6, or 3A4. These findings suggest that FILSUVEZ has no clinically meaningful effect on the PK of drugs metabolized by CYP 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A.