March 22 (Reuters) - U.S. health regulators said on Tuesday they have approved a drug from Eli Lilly and Co to treat adults with moderate to severe cases of the skin condition plaque psoriasis.

The injectable biotech medicine known chemically as ixekizumab will be sold under the brand name Taltz, the Food and Drug Administration said.

Taltz works by blocking a protein that causes inflammation, which is believed to play a role in development of the autoimmune disorder characterized by red skin and thick, unsightly, scaly white patches.

In large, late-stage clinical trials, ixekizumab led to significant skin clearing compared with a placebo and also helped patients who did not respond to Amgen Inc's blockbuster treatment Enbrel.

"Today's approval provides patients suffering from plaque psoriasis with another important treatment option to help relieve the skin irritation and discomfort from the condition," Julie Beitz, from the FDA's Office of Drug Evaluation, said in a statement.

(Reporting by Bill Berkrot in New York; Editing by Matthew Lewis)