More than 125 million people around the world suffer from psoriasis, now a new drug has been approved in Canada that could help many of those affected by the often painful skin condition.

David Wilker knows all too well the discomfort of living with psoriasis.

"It was about 14 years ago I just noticed that I was getting really itchy and I started to see some scales appearing on my skin and over time it just got worse and worse," he says.

Psoriasis is a chronic autoimmune disease characterized by painful and itchy skin lesions.

But there's new hope for people with moderate to severe psoriasis. Health Canada has just approved Cosentyx.

Dermatologist Dr. Lyn Geunther says it's part of a new way of treating psoriasis.

"The drug works amazingly well, so that we are able to, within 12 weeks, have two-thirds of our patients clear or almost clear, which is dramatic. People who were covered top to bottom with psoriasis now are virtually clear."

Psoriasis is a very common condition, affecting some one million Canadians. Of that number, about 28 per cent have what's considered a moderate to severe case.

"If you had 10 'palms' worth' as we call it, or 10 per cent or your body or more, then that would be a patient we would be considering for this type of therapy," Guenther explains.

Cosentyx is administered by injection, and it's not a one-time thing.

She adds, "You'd have to stay on the drug for life. Unfortunately we do not have a cure for psoriasis. But as long as you stay on the drug for life, it seems that you have continuing effect."

Health Canada has approved the drug for adults with moderate to severe psoriasis.