{"nct_id":"NCT00524576","title":"Challenge Dose of Hepatitis B Vaccine in Subjects Who Previously Received Engerix™-B Vaccine","status":"COMPLETED","status_verified_date":"2016-11","start_date":"2007-11-28","start_date_type":null,"primary_completion_date":"2008-05-14","primary_completion_date_type":"ACTUAL","completion_date":"2008-05-14","completion_date_type":"ACTUAL","phases":["PHASE4"],"tickers":["GSK"]}