Clinuvel Pharmaceuticals (ASX:CUV) says it plans to begin evaluating whether its Scenesse subcutaneous implant can repair photodamaged skin in patients with the rarest and most severe light-sensitivity disorder.

Scenesse is already approved for patients with a manageable sensitivity to sunlight known as erythropoietic protoporphyria (EPP); now Clinuvel will study the treatment in the patients with xeroderma pigmentosum (XP), for whom sunlight can be fatal.

Portrayed in movies such as Midnight Sun and The Others, XP leaves patients up to 10,000 times more likely than the general population to suffer skin cancer.

The one in one million people with it have a life expectancy of around just 30 years and are sometimes known as “moon children” because they can only venture outside at night.

Clinuvel said it would study using Scenesse to treat types of xeroderma pigmentosum known as XP-V and XP-C.

The implant improves the function of skin cells that have incurred photodamage from the sun and helps them to repair their DNA. Those with the genetic disorders lack the biological repair mechanism to repair damage from UV radiation from sunlight.

Clinuvel shares were down 1.6 per cent to $28.175 at lunchtime.