Gene Therapy for Dystrophic EB: Extension Study Results Reported

In an extension study of patients with dystrophic epidermolysis bullosa (DEB) treated with the topical gene therapy beremagene geperpavec, wound closure rates and adverse events were similar to those seen in the phase 3 study and no new safety signals were identified.

The results were presented by Amy S. Paller, MD, during a late-breaking session at the annual meeting of the American Academy of Dermatology.

In May 2023, beremagene geperpavec, marketed as Vyjuvek (formerly known as B-VEC) was approved by the US Food and Drug Administration (FDA) for the treatment of wounds in patients 6 months of age and older with DEB, a rare genetic blistering disorder caused by COL7A1 gene variants. The therapy uses a nonreplicating herpes simplex virus type 1 (HSV-1) vector to deliver the COL7A1 gene directly to skin cells, restoring the COL7 protein fibrils that stabilize skin structure. It is designed to be used repetitively, to heal a single wound, or on more than one wound.

In the pivotal study of patients with DEB, the gene therapy, delivered in a topical gel, was administered once a week for 6 months to one wound and placebo was applied to another wound for each participant. The proportion of wounds treated with beremagene geperpavec that healed was significantly higher than among placebo-treated wounds at 3 and 6 months (68% vs. 23% at 3 months, P = .003) and 65% vs. 26% at 6 months (P = .012), with no serious adverse events related to treatment.

The prospective, open label, uncontrolled extension study included 24 patients from the phase 3 study and 23 treatment-naive patients from five US sites. Their mean age was 16 years (range, 6 months to 46 years).

Of the 47 patients, 29 (62%) were on treatment for more than 1 year (the longest was about 2 years), and the mean duration of treatment was 475 days; 5 patients withdrew from the study for reasons not related to treatment.

Their types of adverse events (AEs) were similar to those seen in the phase 3 study and were consistent with what would be expected in patients with DEB, said Dr. Paller, professor and chair of dermatology, Northwestern University, Chicago. One patient experienced two wound hemorrhages that were possibly related to treatment, but there were no treatment-related AEs, no deaths or treatment discontinuations because of an AE, and no serious AEs thought to be related to treatment.

Wounds that were evaluated in the phase 3 study showed “a high durability of closure with continued treatment,” according to Dr. Paller. There were enough data on 19 of the 24 patients who had been in the phase 3 trial to evaluate wound closure, defined as “complete wound closure based on comparison to the exact wound area selected at baseline” at the beginning of the phase 3 study.

In the extension study, wound closure rates were almost 90% at baseline, 84.2% at 3 months, 61.1% at 6 months, 82.4% at 9 months, and 62.5% at 12 months, which was comparable to the rates observed in the third (86.4%) and sixth (73.7%) months of the phase 3 study, Dr. Paller said.

Patient-reported outcomes indicated that quality of life and satisfaction with treatment were preserved with continued treatment.The extension study was terminated in July 2023, after FDA approval, when patients could be transitioned to the commercially available treatment.Dr. Paller disclosed being an investigator (funds to institution) for multiple pharmaceutical companies, including the manufacturer of beremagene geperpavec, Krystal Biotech, which funded the study.

In an extension study of patients with dystrophic epidermolysis bullosa (DEB) treated with the topical gene therapy beremagene geperpavec, wound closure rates and adverse events were similar to those seen in the phase 3 study and no new safety signals were identified.

The results were presented by Amy S. Paller, MD, during a late-breaking session at the annual meeting of the American Academy of Dermatology.

In May 2023, beremagene geperpavec, marketed as Vyjuvek (formerly known as B-VEC) was approved by the US Food and Drug Administration (FDA) for the treatment of wounds in patients 6 months of age and older with DEB, a rare genetic blistering disorder caused by COL7A1 gene variants. The therapy uses a nonreplicating herpes simplex virus type 1 (HSV-1) vector to deliver the COL7A1 gene directly to skin cells, restoring the COL7 protein fibrils that stabilize skin structure. It is designed to be used repetitively, to heal a single wound, or on more than one wound.

In the pivotal study of patients with DEB, the gene therapy, delivered in a topical gel, was administered once a week for 6 months to one wound and placebo was applied to another wound for each participant. The proportion of wounds treated with beremagene geperpavec that healed was significantly higher than among placebo-treated wounds at 3 and 6 months (68% vs. 23% at 3 months, P = .003) and 65% vs. 26% at 6 months (P = .012), with no serious adverse events related to treatment.

The prospective, open label, uncontrolled extension study included 24 patients from the phase 3 study and 23 treatment-naive patients from five US sites. Their mean age was 16 years (range, 6 months to 46 years).

Of the 47 patients, 29 (62%) were on treatment for more than 1 year (the longest was about 2 years), and the mean duration of treatment was 475 days; 5 patients withdrew from the study for reasons not related to treatment.

Their types of adverse events (AEs) were similar to those seen in the phase 3 study and were consistent with what would be expected in patients with DEB, said Dr. Paller, professor and chair of dermatology, Northwestern University, Chicago. One patient experienced two wound hemorrhages that were possibly related to treatment, but there were no treatment-related AEs, no deaths or treatment discontinuations because of an AE, and no serious AEs thought to be related to treatment.

Wounds that were evaluated in the phase 3 study showed “a high durability of closure with continued treatment,” according to Dr. Paller. There were enough data on 19 of the 24 patients who had been in the phase 3 trial to evaluate wound closure, defined as “complete wound closure based on comparison to the exact wound area selected at baseline” at the beginning of the phase 3 study.

In the extension study, wound closure rates were almost 90% at baseline, 84.2% at 3 months, 61.1% at 6 months, 82.4% at 9 months, and 62.5% at 12 months, which was comparable to the rates observed in the third (86.4%) and sixth (73.7%) months of the phase 3 study, Dr. Paller said.

Patient-reported outcomes indicated that quality of life and satisfaction with treatment were preserved with continued treatment.The extension study was terminated in July 2023, after FDA approval, when patients could be transitioned to the commercially available treatment.Dr. Paller disclosed being an investigator (funds to institution) for multiple pharmaceutical companies, including the manufacturer of beremagene geperpavec, Krystal Biotech, which funded the study.

In an extension study of patients with dystrophic epidermolysis bullosa (DEB) treated with the topical gene therapy beremagene geperpavec, wound closure rates and adverse events were similar to those seen in the phase 3 study and no new safety signals were identified.

The results were presented by Amy S. Paller, MD, during a late-breaking session at the annual meeting of the American Academy of Dermatology.

In May 2023, beremagene geperpavec, marketed as Vyjuvek (formerly known as B-VEC) was approved by the US Food and Drug Administration (FDA) for the treatment of wounds in patients 6 months of age and older with DEB, a rare genetic blistering disorder caused by COL7A1 gene variants. The therapy uses a nonreplicating herpes simplex virus type 1 (HSV-1) vector to deliver the COL7A1 gene directly to skin cells, restoring the COL7 protein fibrils that stabilize skin structure. It is designed to be used repetitively, to heal a single wound, or on more than one wound.

In the pivotal study of patients with DEB, the gene therapy, delivered in a topical gel, was administered once a week for 6 months to one wound and placebo was applied to another wound for each participant. The proportion of wounds treated with beremagene geperpavec that healed was significantly higher than among placebo-treated wounds at 3 and 6 months (68% vs. 23% at 3 months, P = .003) and 65% vs. 26% at 6 months (P = .012), with no serious adverse events related to treatment.

The prospective, open label, uncontrolled extension study included 24 patients from the phase 3 study and 23 treatment-naive patients from five US sites. Their mean age was 16 years (range, 6 months to 46 years).

Of the 47 patients, 29 (62%) were on treatment for more than 1 year (the longest was about 2 years), and the mean duration of treatment was 475 days; 5 patients withdrew from the study for reasons not related to treatment.

Their types of adverse events (AEs) were similar to those seen in the phase 3 study and were consistent with what would be expected in patients with DEB, said Dr. Paller, professor and chair of dermatology, Northwestern University, Chicago. One patient experienced two wound hemorrhages that were possibly related to treatment, but there were no treatment-related AEs, no deaths or treatment discontinuations because of an AE, and no serious AEs thought to be related to treatment.

Wounds that were evaluated in the phase 3 study showed “a high durability of closure with continued treatment,” according to Dr. Paller. There were enough data on 19 of the 24 patients who had been in the phase 3 trial to evaluate wound closure, defined as “complete wound closure based on comparison to the exact wound area selected at baseline” at the beginning of the phase 3 study.

In the extension study, wound closure rates were almost 90% at baseline, 84.2% at 3 months, 61.1% at 6 months, 82.4% at 9 months, and 62.5% at 12 months, which was comparable to the rates observed in the third (86.4%) and sixth (73.7%) months of the phase 3 study, Dr. Paller said.

Patient-reported outcomes indicated that quality of life and satisfaction with treatment were preserved with continued treatment.The extension study was terminated in July 2023, after FDA approval, when patients could be transitioned to the commercially available treatment.Dr. Paller disclosed being an investigator (funds to institution) for multiple pharmaceutical companies, including the manufacturer of beremagene geperpavec, Krystal Biotech, which funded the study.