Intravenous gentamicin therapy induces functional type VII collagen in patients with recessive dystrophic epidermolysis bullosa: an open-label clinical trial.

ABSTRACT

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is an incurable widespread blistering skin disorder caused by mutations in the gene encoding for type VII collagen (C7), the major component of anchoring fibrils. OBJECTIVES: To evaluate the efficacy and safety of intravenous (IV) gentamicin readthrough therapy in patients with RDEB harbouring nonsense mutations. The primary outcomes were increased expression of C7 in patients' skin and safety assessments (ototoxicity, nephrotoxicity, autoimmune response); secondary outcomes included measuring wound healing in target wounds and assessment by a validated Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) scoring system. METHODS: An open-label pilot trial to assess two different IV gentamicin regimens between August 2018 and March 2020 with follow-up through to 180 days post-treatment was carried out. Three patients with RDEB with confirmed nonsense mutations in COL7A1 in either one or two alleles and decreased baseline expression of C7 at the dermal-epidermal junction (DEJ) of their skin participated in the study. Three patients received gentamicin 7.5 mg kg-1 daily for 14 days and two of the three patients further received 7.5 mg kg-1 IV gentamicin twice weekly for 12 weeks. Patients who had pre-existing auditory or renal impairment, were currently using ototoxic or nephrotoxic medications, or had allergies to aminoglycosides or sulfate compounds were excluded. RESULTS: After gentamicin treatment, skin biopsies from all three patients (age range 18-28 years) exhibited increased C7 in their DEJ. With both regimens, the new C7 persisted for at least 6 months post-treatment. At 1 and 3 months post-treatment, 100% of the monitored wounds exhibited > 85% closure. Both IV gentamicin infusion regimens decreased EBDASI total activity scores. Of the patients assessed with the EBDASI, all exhibited decreased total activity scores 3 months post-treatment. All three patients completed the study; no adverse effects or anti-C7 antibodies were detected. CONCLUSIONS: IV gentamicin induced the readthrough of nonsense mutations in patients with RDEB and restored functional C7 in their skin, enhanced wound healing and improved clinical parameters. IV gentamicin may be a safe, efficacious, low-cost and readily available treatment for this population of patients with RDEB.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and life-threatening inherited skin disease that causes widespread skin blisters that heal with scarring. RDEB affects around 1 in every 100,000 individuals globally. The condition is caused by a mutation in the gene coding for type VII collagen (C7), resulting in a deficiency of C7. C7 is a vital component of the skin as it is responsible for holding the skin's upper two layers together. To date, there are no approved systemic treatments that can cure RDEB. This study, from the United States, aimed to evaluate the effectiveness and safety of intravenous (medicine delivered directly into a patient's vein) gentamicin (an antibiotic) for people with RDEB who have nonsense mutations in their genes (a type of mutation that prevents the production of complete proteins by introducing an inappropriate 'stop signal'). We gave gentamicin to three patients with RDEB every day for 14 days, and two of the three patients further received intravenous gentamicin twice a week for 12 weeks. After gentamicin treatment, all three patients showed increased expression of C7. With both regimens, the new C7 stayed for at least 6 months after the treatment. At 1 and 3 months after treatment, 100% of the wounds being monitored in the patients had closed by more than 85%. All three patients completed the study, and no side-effects were experienced. In conclusion, intravenous gentamicin increased the production of C7 and improved wound healing and quality of life in patients with RDEB carrying nonsense mutations. Intravenous gentamicin may offer a safe, effective, low-cost and readily available therapy in patients with RDEB.