A Phase 3 study has shown that Amgen Inc.’s drug Nplate helped a majority of children with a bleeding disorder called immune thrombocytopenia, the company announced Wednesday.

The Thousand Oaks biotech said 52 percent of Nplate patients achieved a significant increase in platelet count, compared with 10 percent of placebo-treated patients, according to results of the study published in the Lancet medical journal.

Symptomatic immune thrombocytopenia is chronic in adults but often temporary in children. Patients are at risk for sustained bleeding due to a lack of platelets in the blood. The Federal Drug Administration has approved Nplate for treatment of adults with chronic ITP.

“Nplate helps bone marrow produce more platelets, which in turn helps prevent bruising and bleeding which is important for children faced with this condition,” said Dr. Sean Harper, executive vice president of research and development at Amgen. “We will work with regulatory authorities towards an approval for Nplate for pediatric patients.”

Shares closed up 41 cents or less than 1 percent to $162.76 on the Nasdaq Wednesday.