Adtralza was more effective than a placebo (dummy treatment) at reducing the extent and severity of atopic dermatitis after 16 weeks of treatment in three main studies in adult patients with moderate to severe disease that had not responded well enough to treatment applied to the skin. The main measures of effectiveness were having clear or almost clear skin, and a reduction in symptom score of at least 75%.

In the first study, which involved 802 patients, around 16% of patients who received Adtralza had clear skin or almost clear skin compared with 7% of those who received placebo. Symptoms were satisfactorily reduced in 25% of patients who received Adtralza, compared with about 13% of those who received placebo.

In the second study, involving 794 patients, treatment with Adtralza led to clear or almost clear skin in about 22% of patients, compared with around 11% of patients who used a placebo. Symptoms were satisfactorily reduced in 33% of patients receiving Adtralza versus about 11% of those receiving placebo.

In the third study, 380 patients were given Adtralza or placebo, both in combination with a topical corticosteroid (a medicine for inflammation applied to the skin). Adtralza treatment led to clear or almost clear skin in around 39% of patients versus 26% of those receiving placebo. Symptoms were satisfactorily reduced in 56% of the patients who received Adtralza, compared with about 36% of patients on placebo.

In an additional study involving 301 children aged between 12 and 17 years with atopic dermatitis, treatment with Adtralza 300 mg every two weeks for 16 weeks led to clear or almost clear skin in around 18% of patients, while treatment with 150 mg every other week for 16 weeks led to clear or almost clear skin in around 21% of patients. This compared with around 4% of patients who used a placebo.