A Phase 2/3 interventional study of Botulinic toxin and Placebo in Epidermolysis Bullosa Simplex, sponsored by University Hospital, Toulouse. Completed at 4 sites in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-21.
Sponsored by University Hospital, Toulouse · Phase 2/3, Interventional, and Treatment
The investigators hypothesize that palmar injections of botulinic toxin, via an inhibition of the sudation, would limit the occurrence of blisters in localized epidermolysis bullosa simplex (LEBS).
Epidermolysis bullosa is a group of rare genetic diseases characterized by the occurrence of blisters and erosions due to skin fragility. There are 4 different subgroups, based on the location of the skin cleavage area. The most frequent subgroup is the simplex form, consisting predominantly of the localized form (localized epidermolysis bullosa simplex: LEBS). The incidence of LEBS was estimated at between 1/318.000 and 1/35.000. The disease starts early in infancy by the occurrence of blisters and erosions located on soles, secondary to frictions during the walk. The phenomenon is worsened by heat and sudation. LEBS is due to mutations in keratin genes. Life expectancy in LEBS is normal but the quality of life is significantly impaired due to permanent skin pain and limitation of everyday activities (walking, sports). There is no effective or curative treatment. Patients must limit the frictions, protect the skin and use plasters in case of skin lesions.
Botulinic toxin has an agreement for the treatment of axillary hyperhidrosis and has been shown to be also effective on palms and soles. The efficacy of botulinic toxin in plantar lesions of LEBS has been reported in the literature (one case report and a short retrospective series of 6 patients) but there is no proper study.
Exclusion Criteria:
Injections of botulinic toxin (Dysport®, Allergan) 200 UI
Drug: Botulinic toxin
Injections of physiological serum
Drug: Placebo
Clinical photographs of the soles Standardized anesthesia protocol (lidocaine, prilocaine on soles, cryo-spray, oral administration of paracetamol and only if necessary oxycodone and hydroxyzine). Cleaning and antiseptic on the soles Injections of botulinic toxin (200 UI) on right or left foot
Also known as: Dysport® (experimental drug)
Clinical photographs of the soles Standardized anesthesia protocol (lidocaine, prilocaine on soles, cryo-spray, oral administration of paracetamol and only if necessary oxycodone and hydroxyzine). Cleaning and antiseptic on the soles Injections of physiological serum (200 UI) on right or left foot
Also known as: physiological serum
Global clinical improvement on each foot assessed by a blinded centralized independent reviewer using photographs, at M3 vs.baseline: IGA score (Improvement Global Assessment) assessed for each foot
IGA score is a 5-point scale (range from 0 to 4): 0=no improvement or worsening / 1=minimal improvement / 2=moderate improvement / 3=significant improvement / 4=total disappearance
Time frame: at baseline vs month 3
Global clinical improvement on each foot assessed by a blinded centralized independent reviewer using photographs: IGA score (Improvement Global Assessment) for each foot
IGA score is a 5-point scale (range from 0 to 4): 0=no improvement or worsening / 1=minimal improvement / 2=moderate improvement / 3=significant improvement / 4=total disappearance
Time frame: at baseline vs month 6
Global clinical improvement on each foot assessed by the investigator: IGA score (Improvement Global Assessment) assessed for each foot.
IGA score is a 5-point scale (range from 0 to 4): 0=no improvement or worsening / 1=minimal improvement / 2=moderate improvement / 3=significant improvement / 4=total disappearance
Time frame: at month1, month 3 and month 6 respectively vs baseline
Efficacy assessment concerning the number of plantar lesions clinically observed by the investigator
on each foot (erythematous and edematous areas, blisters, skin erosion, crusts)
Time frame: at baseline, month 1, month 3 and month 6
Efficacy assessment on each foot of the affected plantar skin surface (blisters, erosions, erythematous and edematous areas, crusts)
calculation of this affected surface by delimiting its contours on a standardized photography using "Image J" software = computerized assessment by a blinded centralized independent reviewer.
Time frame: at baseline, month 1, month 3 and month 6
Efficacy assessment by the patient himself, for each foot
Global improvement assessed with a 5-point score (0=no improvement or worsening / 1=minimal improvement / 2=moderate improvement / 3=significant improvement / 4=total disappearance)
Time frame: at month 1, month 3, month 6 and month 9
Plantar pain assessment by the patient himself, for each foot
Plantar pain assessment , using a 0 to 10 pain EVA scale. To perform the assessment, patient is requested to be standing on one foot (assessment of pain felt for this foot using EVA scale) then, standing on the other foot (assessment of pain felt for this other foot using EVA scale).
Time frame: at baseline, month 1, month 3 and month 6
Immediate tolerance during injection :
Assessment performed by the patient of the pain felt during the act for each foot, using a 0 to 10 pain EVA scale (patient interview). Assessment performed by the investigator of local adverse events (for each foot) or general adverse events, during the injections
Time frame: Day 0
Mid-term and long-term tolerance
Assessment performed by the patient of local adverse events (for each foot) or general adverse events reported in the home patient's diary between the protocol visits (collected at month 1, month 3, month 6 and month 9). • Assessment performed by investigator of local adverse events (for each foot) or general adverse events, at D0 (at the end of/after the injections), M3 and M6.
Time frame: Day 0, month 1, month 3 and month 6 and month 9
Plan to share: No
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Epidermolysis Bullosa Simplex
University Hospital, Toulouse