Filsuvez in Moderate-to-Severe Epidermolysis Bullosa Simplex (FILS-EBS)

A Pilot Trial to Evaluate the Efficacy and Safety of Filsuvez in the Treatment of Moderate-to-Severe Epidermolysis Bullosa Simplex

This pilot study will look at whether the topical Birch Triterpenes (Filsuvez) gel is safe and helpful for adults and children 6 months of age and older who have moderate to severe epidermolysis bullosa simplex (EBS). The study will examine whether the gel can reduce the number of blisters, help wounds heal faster, and improve comfort by reducing pain and itching and making daily activities easier.

Study Overview

• Status: Not yet recruiting
• Conditions: Epidermolysis Bullosa Simplex
• Intervention / Treatment: Drug: Filsuvez

• Study Type: Interventional
• Enrollment (Estimated): 10
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • California
    • Palo Alto, California, United States, 94304
      • Stanford University School of Medicine
      • Principal Investigator: Joyce M. C. Teng, MD PhD
      • Sub-Investigator: Chaw-Ning Lee, MD PHD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Subject has a documented diagnosis and confirmed clinical history of EBS. The Investigator will determine subject eligibility based on historical phenotypic presentation of EBS symptoms along with genetic/diagnosis documentation in order to determine EBS severity.

• The following skin conditions are required:

  • A minimum area of ~3% BSA containing active blisters/erosions, and freshly ruptured blisters across 50% of the TLA (as assessed by the PI). Skin erosions, keratoderma, fissures and/or erythema may also be present.
  • Subjects will be permitted to treat their feet to assess plantar blister surface area but blistering on the feet is not a requirement for study inclusion.
  • TLA may not be infected (as assessed by PI) or have been treated with a topical antibiotic within 14 days.

• If the subject is a woman of childbearing potential (WOCBP) (Need to verify current labeling on use during pregnancy)

  • Has a negative urine pregnancy test at baseline.
  • Agrees to use an approved effective form of birth control with failure rates <1% per year (e.g., implant, injectable, combined oral contraceptive, intrauterine contraceptive device, sexual abstinence, vasectomized partner) during participation in the study.
  • Is not nursing.
• Subject's laboratory values (blood and urine) are within the range of normal or abnormal values are within normal levels for the disease and in the opinion of the PI the values are not clinically relevant for study participation.
• Subject is in good, general health and free of any known disease state or physical condition which, in the investigator's opinion, might interfere evaluation of the EBS lesions during study or which exposes the subject to an unacceptable risk by study participation.
• Over the duration of the study, the subject agrees to not use any other topical therapies and/or impregnated dressings within the TLAs (e.g., medicated cleansers, CBD oil, MediHoney, Silvadene cream 1%, topicals containing antimicrobials, keratin, and/or collagen, lipid-colloid or polymeric membrane dressings, and/or hydrogels).
• Subject and/or legally appointed and authorized representative must be able and willing to follow study procedures and instructions to maintain compliance throughout the study period.
• The subject, parent, or legally appointed and authorized representative must have read, understood and signed an Institutional Review Board/Ethics Committee (IRB/EC) approved Informed Consent and Assent Form if applicable.

Exclusion Criteria:

• Subject's use of prior or concomitant medication or medical treatments/procedures:

  • Any investigational drug or therapy within 30 days.
  • Systemic steroidal therapy within 30 days.
  • Topical steroidal therapy in TLA within 14 days (Note: inhaled and ophthalmic products containing steroids are allowed).
  • Systemic antibiotic therapy within 7 days.
  • Currently receiving chemotherapy or radiation.
  • Surgery within the previous 2 weeks (except for minor surgery, cosmetic or dental procedures as determined by the investigator).
  • Started to take chronic medications (NSAIDs, antihistamines, etc.) at least 30 days prior to starting study medication.

• Subject's medical history includes:

  • Cancer that is currently undergoing treatment.
  • Current systemic or ongoing skin infection.
  • HIV/AIDS.
  • Non-EBS skin disease (e.g., psoriasis, atopic dermatitis, etc.), or condition (e.g., sunburn) that, in the opinion of the investigator, might put the subject at undue risk by study participation or interferes with the study medication application or the study assessments.
  • An illness (e.g., neurological, cardiovascular, respiratory, hepatic, renal, or metabolic disease), condition, or situation that in the opinion of the principal investigator is likely to interfere with the subject's participation in or completion of the study.
• Factors present in the subject and/or his/her legal representative that could interfere with study compliance such as inability to attend scheduled study visits or to perform study protocol procedures.
• Subject is a member of the investigational team or his/her immediate family.
• Other unspecified reasons that, in the opinion of the Investigator, make the subject unsuitable for enrollment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Filsuvez; All the participants will apply Filsuvez about 3% BSA for 3 months and a follow-up visit 2 months later.	Drug: Filsuvez; All the participants will apply Filsuvez about 3% BSA for 3 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Blister surface area reduction of the target treatment areas	Clinical photography will be used to assess changes in disease severity within the TLA and recurrence of blistering by measuring blister surface area in the TLA over time.	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in EBSdart scores	Epidermolysis Bullosa Simplex Disease Activity and Response Tool (EBSdart) grades blistering and erosions/ulcerations in all body regions and fissures and keratoderma on the palms and soles, including the area affected. IGA regional subscores are recorded separately for the palms, soles, trunk, upper extremities, and lower extremities, using palm- and sole-specific criteria where applicable. A score range from 0-99, where higher scores indicate severe condition.	From enrollment to the end of treatment at Week12 and Week20 (EOS).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Palmoplantar Blister Surface Area	Clinical photography will be used to assess changes in disease severity within the Palmoplantar blister surface area and recurrence of blistering by measuring blister surface area in the Palmoplantar blister surface area over time.	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in Pain Score in Target Lesional Areas	Using the adult or pediatric Patient-Reported Outcomes Measurement Information System (PROMIS) Measure form, peak pain during IP application will be reported on a weekly basis. Pain will be compared between baseline and at the end of treatment. The appropriate PROMIS Pain Interference Short Form will be administered based on the participant's age: the Adult Pain Interference Short Form 8a, the Pediatric Pain (8yo+) Interference Short Form 8a, or the Parent Proxy Pain (6m-8yo) Interference Short Form 8a. Each item is scored on a 5-point Likert scale (1-5), where higher scores indicate greater pain interference with daily activities (1 = Not at All; 5 = Very Much).	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in Itch Score in Target Lesional Area	Using the adult or pediatric PROMIS Measure form (8 yo +), itch characteristics will be reported on a weekly basis to track trends in how itch impacts daily living in Birch triterpenes at baseline versus 3 mo post treatment. The appropriate PROMIS Pain Interference Short Form will be administered based on the participant's age: the Adult Itch Interference Short Form 8a, the Pediatric Itch Interference Short Form 8a, or the Parent Proxy Itch (6m-8yo) Interference Short Form 8a. Each item is scored on a 5-point Likert scale (1-5), where higher scores indicate greater pain interference with daily activities (1 = Never; 5 = Almost always).	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in Quality of Life	Participant's quality of life metrics will be reported on a weekly basis to track trends at baseline versus 3 mo post Birch Triterpenes treatment. The Quality of Life in Epidermolysis Bullosa (QOLEB) questionnaire is a disease-specific instrument consisting of 17 items. Each item is scored on a 4-point scale (0-3), yielding a total score ranging from 0 to 51, with higher scores indicating poorer quality of life and greater disease burden.	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in Modified Foot Function Index(mFFI)	Participant's mFFI will be reported on a biweekly basis to track changes with Birch Triterpenes. The Modified Foot Function Index (mFFI) consists of 27 items that assess foot pain, disability, and activity limitation. Each item is rated on an 11-point numeric rating scale (0-10), where 0 indicates no pain/no difficulty/Not at all and 10 indicates the worst pain imaginable or greatest difficulty/all the time. Total scores range from 0 to 270, with higher scores representing worse foot function and greater disability.	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Safety: Incidence of treatment-emergent adverse events (TEAEs)	Safety monitoring will include clinical chemistry tests, physical examinations (including assessment of TLA), and vital sign measurements. These assessments along with AE reviews will identify potential TEAEs. Safety monitoring will include clinical laboratory testing (blood and urine) and urine pregnancy testing (as appropriate) only at Visit 1/Screening and visit 4/EOS.	From enrollment to the end of treatment at Week12 and Week20 (EOS).
Change in Palmoplantar Blister Surface Area- EBSDart scores	EBSdart grades blistering and erosions/ulcerations in all body regions and fissures and keratoderma on the palms and soles, including the area affected. IGA regional subscores are recorded separately for the palms, soles, trunk, upper extremities, and lower extremities, using palm- and sole-specific criteria where applicable. A score range from 0-99.	From enrollment to the end of treatment at Week12 and Week20 (EOS).

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Principal Investigator: Joyce Teng, MD, PhD, FAAD, Stanford University

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): July 2, 2027
• Study Completion (Estimated): June 18, 2028

Study Registration Dates

• First Submitted: July 24, 2026
• First Submitted That Met QC Criteria: August 5, 2026
• First Posted (Actual): August 10, 2026

Study Record Updates

• Last Update Posted (Actual): August 10, 2026
• Last Update Submitted That Met QC Criteria: August 5, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Skin Diseases; Congenital Abnormalities; Skin Diseases, Genetic; Skin Abnormalities; Skin Diseases, Vesiculobullous; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Skin and Connective Tissue Diseases; Epidermolysis Bullosa; Epidermolysis Bullosa Simplex
• Other Study ID Numbers: IRB-87068

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes