Gene-Guided reflux drug may tame childhood asthma

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age: 6-17 year olds with documented clinician-diagnosed asthma * Evidence of recent uncontrolled asthma (must meet at least one of the following). This convention for defining poorly-controlled asthma has been successfully used in a large pediatric trial. * ACQ \> 1.2 * Use of short-acting beta-agonist for asthma symptoms twice/week or more on average over the past month * Nocturnal awakenings with asthma symptoms more than once per week on average over the last month * Two or more emergency department visits, unscheduled provider visits, prednisone courses or hospitalizations for asthma in the past 12 months * Currently on stable dose of daily inhaled corticosteroid medication (ICS) for asthma control equivalent to 88mcg of fluticasone or greater for at least 6 weeks from the time of enrollment. Participant must be on National Asthma Education and Prevention Program (NAEPP) controller step 2, 3 or 4. * Currently with mild GERD symptoms reported at V1 defined by a score on the Pediatric GERD Symptom Assessment Score greater than 15 and less than 80. GSAS ranges from 0 to \>440. Exclusion Criteria: * Taking daily CYP2C19 substrates, inducers or inhibitors medication * Past or current history of moderate-severe GERD or related disorders (erosive esophagitis, peptic ulcer disease, eosinophilic esophagitis) which in the opinion of the pediatric gastroenterology safety specialist/study physician requires treatment with acid-blocking agents; * Daily use of a PPI for more than 4 consecutive weeks in the past 6 months; * previous intubation for asthma, * admission to intensive care unit for more than 24 hours for asthma in the past year, * Previous surgery involving the esophagus or stomach (anti-reflux surgery, peptic ulcer surgery, trachea-esophageal fistula repair); * Forced expiratory volume in 1 second (FEV1) \< 60% of predicted at enrollment; * Any major chronic illness that would interfere with participation in the intervention or completion of the study procedures; * History of phenylketonuria (PKU); * Medication use: treatment of GERD symptoms with over-the-counter antacids 4 days/week or more on average over past month; * Theophylline preparations, azoles, anti-coagulants, insulin for Type 1 diabetes, digitalis, oral iron supplements when administered for iron deficiency within 1 month; * Any investigational drugs within the past 2 months; * Drug Allergies: previous allergic reaction from lansoprazole or other proton pump inhibitor medication or adverse reaction to aspartame; * Inability to complete baseline measurements in a satisfactory manner according to the judgment of the research coordinator or site PI; * Less than 75% completion of daily diary for asthma symptoms, SABA use and ICS medication adherence during the run-in period; * Plan for family to move from study location within the next 6 months.