Type 1 diabetes and psoriasis are both autoimmune disorders. In type 1 diabetes the body's immune system defenses end up attacking insulin-producing cells in the pancreas. This attack by the effector memory T (Tem) cells of the immune system causes insulin deficiency, and without enough insulin you cannot regulate your blood sugar levels.
The skin condition known as psoriasis is actually a chronic (long-lasting) disease of the immune system in which the immune system mistakenly activates a reaction in the skin cells. The activation speeds up skin cell growth causing inflamed, itchy, red patches of skin.
Newer immunosuppressive drugs such as alefacept have a much more specific effect. They target the immune cells responsible for the disorder, while sparing the cells essential for normal immune functioning.
The two disorders share a common immune system connection — both are triggered by Tem cells. That's why scientists began looking at the drug alefacept (marketed as Amevive) which has been used for about a decade to treat psoriasis. Alefacept targets a protein expressed on the surface of the Tem cells and eradicates them.
Past clinical trials have tested drugs that suppress the immune system to treat type 1 diabetes, but the risks of long-term immunosuppressant therapy outweighed the benefits. However, newer immunosuppressive drugs such as alefacept have a much more specific effect. They target the immune cells responsible for the disorder, while sparing the cells essential for normal immune functioning.
The investigators found that alefacept reduced insulin use as well as the number of hypoglycemic events compared to placebo. These findings suggest that alefacept has potential as a treatment for type 1 diabetes. The drug did not, however, completely overcome the faulty immune response associated with the disease, and patients had to continue to take insulin.
“What we would like to do is a larger study to confirm our results before we could pursue the therapy as an option for type 1 diabetes,” Mark Rigby, corresponding author on the study, told TheDoctor.
Unfortunately, the manufacturer of alefacept decided to pull the drug from the market because it was losing market share to other agents used to treat psoriasis.
The current study only examined the effect of alefacept compared to placebo at 12 months, The investigators would like to see if the effects of alefacept were sustained at 18 months and 24 months.
Although no participants in the current study were able to completely come off insulin, they did produce more of their own. When patients have some insulin of their own, it makes management of type 1 diabetes much easier, and the complications of type 1 diabetes, such as nerve, kidney, and heart disease, can be reduced. Another possibility would be to combine alefacept with other drugs to allow patients to become insulin independent, Rigby said.
The study is published in The Lancet Diabetes & Endocrinology.