US regulators have granted orphan drug designation to AbbVie's Humira (adalimumab) as a potential treatment for a rare but serious group of inflammatory diseases of the eye.

The US Food and Drug Administration's award for the drug relates to the treatment of non-infectious intermediate, posterior, or pan-uveitis, or chronic non-infectious anterior uveitis, conditions which can lead to reduced vision or vision loss.

While the exact cause of uveitis remains unknown, it can be caused by an infection, autoimmune disease, medication, surgery or trauma to the eye, and it is estimated to account for 10% to 15% of all cases of total blindness in the US.

And yet there are "few well characterised treatment options" available for patients suffering from uveitis, said Scott Brun, vice president of Pharmaceutical Development at AbbVie, noting that Humira's orphan drug designation "recognises the significant unmet need that exists within this disease".

AbbVie is currently investigating the efficacy and safety of Humira for the treatment of non-infectious uveitis in Phase III trials. 

The anti-inflammatory is already on the US market for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, chronic plaque psoriasis, pulling in annual sales of around $2.6 billion.