THOUSAND OAKS, Calif. — A drug used to treat inflammatory diseases improved the conditions of patients with psoriasis that affected the scalp compared with placebo, according to results of a new study.

Amgen and Pfizer on Friday announced the results of the phase-4 study of Enbrel (etanercept), in patients with moderate to severe plaque psoriasis with scaling on the scalp, also known as scalp involvement. Data from the trial will be presented Friday at the 69th annual meeting of the American Academy of Dermatology in New Orleans.

The 121-patient trial divided patients into Group A, which received 50-mg of Enbrel twice weekly for 12 weeks followed by the same dosage once weekly for another 12 weeks, and Group B, which received a placebo for 12 weeks followed by Enbrel twice a week for another 12 weeks. Among the patients, 87% of those in Group A showed improvement in scalp involvement after the first 12 weeks, compared with 20% of those in Group B.

“At least half of people with plaque psoriasis have involvement on their scalp, which may contribute to feelings of embarrassment associated with this condition,” said Jerry Bagel, lead study author and medical director of the Psoriasis Treatment Center of Central New Jersey. “These data reinforce the efficacy and safety profile of Enbrel for adult patients with moderate to severe plaque psoriasis with scalp involvement.”