The purpose of this study is to understand how quickly lansoprazole, once daily (QD), improves feeding in premature babies or babies less than 28 days of age.

A Phase 1, multi-center, pharmacokinetic/pharmacodynamic and safety, study in which neonates will be randomized in an open-label fashion to receive 5 days of open-label treatment with either lansoprazole pediatric suspension 1.0 mg/kg/day orally or lansoprazole pediatric suspension .5 mg/kg/day orally. On dosing Days 1 and 5, blood samples will be obtained for drug assay. All subjects will be evaluated for inclusion in the pH monitoring portion of the study and will undergo pH monitoring, provided it is clinically indicated, at the discretion of the investigator. Intragastric pH monitoring (up to 24 hours) will be performed at baseline, on dosing Day 1 (or Day 2) and on dosing Day 5 (or Day 6). Intraesophageal pH may be done in addition to intragastric pH at the discretion of the investigator. Subjects will be evaluated for safety, including a follow-up visit on post-dosing Day 14.

Inclusion Criteria:

• Neonates in the Neonatal Intensive Care or Special Care Nursery who have been fed orally or by feeding tube.
• Term or post-term infants with a body weight of >800 gms.
• Pre-term infants with a corrected age of less than 44 weeks.
• Clinically-evident GERD (feeding intolerance, regurgitation, wheezing or stridor with feedings)
• At least 7 days post-surgery without anticipated need for surgery during study
• No significant laboratory abnormalities

Exclusion Criteria:

• Unstable, clinically significant disease or abnormality
• Congenital anomaly of the upper gastrointestinal tract
• Clinical evidence of acute sepsis
• Cystic fibrosis
• Medical condition requiring subject to not be fed by mouth/gastric tube