Oral GP-SOD Plus Targeted Phototherapy Boosts Vitiligo Repigmentation

Adding oral gliadin-protected superoxide dismutase (GP-SOD) to targeted excimer phototherapy produced significantly greater repigmentation than phototherapy alone in patients with localized non-segmental vitiligo, according to a new randomized, single-blinded study.¹

The trial, published ahead of World Vitiligo Day, was led by Giovanni Leone, MD, of the Photodermatology and Vitiligo Treatment Center at Israelite Hospital.

“[The study] was not just [intended] to confirm the effectiveness of GP sod together with UVB but to see if by using a more powerful source for targeted phototherapy…we could obtain even better results, and that has been the case,” Leone told HCPLive.

GP-SOD and Targeted Phototherapy Study Design

The 6-month trial enrolled 40 adults with localized non-segmental vitiligo. All participants received targeted excimer lamp phototherapy, and half also received oral GP-SOD. Patients on the combination regimen showed significantly greater repigmentation than those on phototherapy alone, along with significantly greater improvements in quality of life. No serious adverse events were reported.

Leone said the trial builds on earlier work from Nice testing GP-SOD with conventional narrowband UVB booths.² Switching to a more targeted excimer source, he said, produced stronger repigmentation than the earlier booth-based results while limiting UV exposure to lesional skin.

Vitiligo Repigmentation Outcomes by Skin Phototype

Most enrolled patients had Fitzpatrick skin types III and IV, reflecting the study's Italian patient population.¹ Leone said this worked in the trial's favor clinically.

“As in other publications in the literature on vitiligo, it has been clearly demonstrated that the response to phototherapy is better in darker skin types,” he said.

VASI Score Timeline: When to Assess Treatment Benefit

Leone said the between-group difference in Vitiligo Area Scoring Index (VASI) improvement was statistically significant by week 12 and widened by week 24. He said 6 months remains the standard window for judging benefit, though earlier improvement at 3 months suggests clinicians may eventually be able to shorten phototherapy courses and reduce cumulative UV exposure.

GP-SOD Versus JAK Inhibitors in Vitiligo Treatment

Asked how GP-SOD fits alongside JAK inhibitors now used in vitiligo, Leone said the combination logic is similar. JAK inhibitors and GP-SOD both limit autoimmune damage to melanocytes, he said, but neither drives melanocyte proliferation on its own. Phototherapy remains the primary stimulus for melanocyte growth, making it a natural pairing for either approach.

Quality of Life Gains Outpace Repigmentation Scores

Leone said quality-of-life improvement outpaced objective VASI gains, which he attributed partly to the tolerability of targeted phototherapy compared with conventional whole-body narrowband UVB. He said easier treatment adherence, alongside the biological effect of GP-SOD, likely contributed to the larger quality-of-life signal.

“The therapy is easier to follow and has [fewer] side effects as compared to systemic or conventional total body narrowband UVB,” he said.

Leone has no reported disclosures.

References

1. Leone G, Bertold C, Vidolin AP, Fontas E, Passeron T. Combination of Oral Gliadin-Protected Superoxide Dismutase With Targeted Phototherapy in Vitiligo: A Prospective, Comparative, Randomized, Single-Blinded Study. Photodermatol Photoimmunol Photomed. 2026;42(4):e70105. doi:10.1111/phpp.70105

2. Fontas E, Montaudié H, Passeron T. Oral gliadin-protected superoxide dismutase in addition to phototherapy for treating non-segmental vitiligo: A 24-week prospective randomized placebo-controlled study. J Eur Acad Dermatol Venereol. 2021;35(8):1725-1729. doi:10.1111/jdv.17331