Molecular and Clinical Outcomes After Intravenous Gentamicin Treatment for Patients With Junctional Epidermolysis Bullosa Caused by Nonsense Variants

Abstract

Importance: Junctional epidermolysis bullosa (JEB) is an incurable blistering skin disorder with high infant mortality often caused by nonsense variants in the genes that encode laminin 332.

Objective: To evaluate the safety and outcomes following intravenous gentamicin readthrough therapy and subsequent laminin 332 expression in patients with JEB.

Design, setting, and participants: This open-label, pilot nonrandomized clinical trial assessed 1 course of low- or high-dose intravenous gentamicin, including follow-up at 30 and 90 days after treatment. Five pediatric patients with JEB (2 with intermediate JEB and 3 with severe JEB) and confirmed nonsense variants in LAMA3 or LAMB3 in 1 or 2 alleles and decreased expression of laminin 332 at the dermal-epidermal junction of their skin participated in the study, which was performed at a single institution in collaboration with physicians and home infusion services near the patients from April 1, 2019, to February 28, 2021, with follow-up until May 31, 2021.

Interventions: Three patients received gentamicin at 7.5 mg/kg daily for 14 days, and 2 patients received gentamicin at 10 mg/kg daily for 24 days.

Main outcomes and measures: Primary outcomes were change in expression of laminin 332 in patients' skin and assessments for safety (ototoxic effects, nephrotoxic effects, and autoimmune response). Secondary outcomes included wound healing in monitored wounds and Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) score.

Results: After gentamicin treatment, all 5 patients (age range, 3 months to 10 years, 4 [80%] female) exhibited increased laminin 332 in the dermal-epidermal junction. By 1 month, 7 of 9 wounds in patients receiving low-dose intravenous gentamicin and all wounds in patients receiving high-dose intravenous gentamicin exhibited at least 50% wound closure. By 3 months, 8 of 9 wounds in patients receiving low-dose gentamicin and all wounds in patients receiving high-dose intravenous gentamicin exhibited greater than 85% closure. All 3 patients who were evaluated with EBDASI showed a decrease in total activity scores that met minimal clinically important differences 1 month after treatment. All 5 patients completed the study, and no ototoxic effects, nephrotoxic effects, or anti-laminin 332 antibodies were detected.

Conclusions and relevance: In this nonrandomized clinical trial, intravenous gentamicin therapy was associated with induced readthrough of nonsense variants in patients with JEB, restored functional laminin 332 in their skin, and wound closure during the 3-month study period. Although long-term safety and efficacy requires further evaluation, a single cycle of intravenous gentamicin may be a safe and readily available therapy in the short term for this population of patients with JEB.

Trial registration: ClinicalTrials.gov Identifiers: NCT03526159 and NCT04140786.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Woodley and Dr Chen both reported receiving grants from Epidermolysis Bullosa Research Partnership and Epidermolysis Bullosa Medical Research Foundation during the conduct of the study and personal fees from Phoenix Tissue Repair outside the submitted work. No other disclosures were reported.

Figures

Figure 1.. Expression of Laminin 332 in the Skin of Patients With Junctional Epidermolysis Bullosa (JEB)

Immunofluorescent staining of skin biopsy specimens from all 5 patients with JEB taken from intact skin sites before treatment (day 0) and from healed periwound sites at 1 month (day 30) after gentamicin treatment using antibodies that specifically target the 3 chains (α3, β3, or γ2) of laminin 332 or the β4 integrin. Note that within the selected wound sites, gentamicin induced continuous expression of all 3 chains of laminin 332 at the dermal-epidermal junction of all 5 patients. In addition, the β4 integrin is increased and polarized along the entire dermal-epidermal junction after treatment. All images were obtained using the same camera and identical exposure times. Scale bars are 50 μm. HDIV indicates high-dosage intravenous; LDIV, low-dosage intravenous; NHS, normal human skin.

Figure 2.. Improvement of Wound Closure

Representative photographs of the open erosions before treatment (day 0) and at 1 month and 3 months after treatment with intravenous gentamicin. Patients 1 to 3 were treated with low-dosage intravenous gentamicin, and patients 4 and 5 were treated with high-dosage intravenous gentamicin. All monitored wound sites demonstrated improved wound closure with intravenous gentamicin. Scale bars are 1 cm.