Bringing a ray of hope for patients with dystrophic epidermolysis bullosa, the US FDA has granted its approval to the first-ever topical gene therapy for the treatment of wounds in patients aged ≥6 months with this rare but devastating skin condition.^1,2 To be available by the name of Vyjuvek, the therapy is a herpes-simplex virus type 1 (HSV-1) vector-based gene therapy.

The characteristic feature of dystrophic epidermolysis bullosa is a mutation in the COL7A1 gene, which is responsible for formation of type VII collagen (COL7). This collagen keeps the outer and middle layers of skin stable and intact. Deficiency of COL7A1 gene results in separation of skin layers causing painful and debilitating blisters and wounds. The disease is inherited as a dominant or recessive pattern. The recessive disease is more severe and debilitating than the dominant type with extensive blisters, often as a result of trauma sustained during birth. In the dominant type, the blisters are predominantly seen on hands, elbows, knees and feet.

Dose and administration: It is first mixed into an inactive excipient gel and is then applied topically on the wound once in a week by a healthcare professional.

Adverse effects: Itching, redness, rash, chills, cough and runny nose

Warning and precautions

• Touching and/or scratching the treated wound should be avoided for at least a day after application. Direct contact with the dressings of the treated wounds should also be avoided. Clean the affected areas, if accidental exposure occurs.
• Always wash hands and wear gloves when changing the wound dressings.
• The bandages/gauze from the first dressing change should be disinfected with a virucidal agent (70% isopropyl alcohol, 6% hydrogen peroxide, or <0.4% ammonium chloride) and then discarded in the household waste in a separate sealed plastic bag. Then, the dressings, gauze etc. should be disposed of into a sealed plastic bag in household waste.

References

1. FDA News Release. Available at: https://www.fda.gov/news-events/press-announcements/fda-approves-first-topical-gene-therapy-treatment-wounds-patients-dystrophic-epidermolysis-bullosa. May 19, 2023. Accessed on May 20, 2023.
2. FDA OKs first-ever topical gene therapy, for rare skin disease - Medscape - May 19, 2023.