Eye inflammation may occur in patients on subretinal gene therapy

Signs of intraocular inflammation must be checked in patients receiving subretinal voretigene neparvovec (VN), suggests a study in Denmark.

“Although we did not observe a detrimental effect on visual function in eyes with inflammation, it seems wise to treat it appropriately because it may lead to atrophy of the retinal pigment epithelium and outer retina,” the researchers said. “Also, it seems advisable to reduce the inflammatory load, such as using a surgical technique that minimizes residual viral vectors in the vitreous body.”

In this study, medical files of 12 patients undergoing VN gene therapy as standard of care for biallelic RPE65-related retinal disease were retrospectively reviewed. Of the participants, 11 had bilateral treatment and one underwent unilateral treatment.

The researchers clinically followed patients before and after VN administration using functional measurements (ie, visual acuity, full-field scotopic threshold test, visual fields) and structural evaluations (fundus imaging [colour and autofluorescence], optical coherence tomography, slit-lamp).

Nine of 23 eyes administered VN had vitritis, with a median time to vitritis resolution of 89 days from the time of treatment. Four eyes also presented with outer retinal infiltrates at the time of vitritis. Inflammation subsided following immunosuppressant therapy, and the presence of inflammation did not have a negative impact on visual outcome after VN therapy.

Of note, outer retinal infiltrates in one eye were shown to precede later development of atrophy.