QVM149 vs Salmeterol/Fluticasone for Asthma in Teens

Key Inclusion criteria: * Male and female adolescent participants aged from ≥ 12 years old to less than 18 years old at screening visit * Participants with a documented diagnosis of persistent asthma (according to Global Initiative for Asthma GINA 2024) for a period of at least 1 year prior to screening. * Participants who have used medium or high dose ICS with LABA in combination (GINA 2024) for asthma for at least 3 months and at stable doses for at least 1 month prior to screening * Participants must be symptomatic / inadequately controlled according to the Investigator's opinion despite treatment with medium or high stable doses of ICS with LABA in combination (GINA 2024) before screening * Participants who demonstrate an increase in FEV1 of ≥ 12% within 15 to 30 minutes after administration of 200-400 μg salbutamol/180-360 μg albuterol at run-in visit * Pre-bronchodilator FEV1 ≥ 50% of the predicted normal value for the participant according to American Thoracic Society/European Respiratory Society (ATS/ERS) 2019 criteria at both run-in and before randomization Key Exclusion criteria: * Participants who have had a severe asthma attack/exacerbation requiring systemic steroids OR hospitalization (\> 24 hours) OR emergency room (ER) visit (≤ 24 hours) within 6 weeks of screening. If participants experience an asthma attack/exacerbation requiring systemic steroids or emergency room visit between screening and end of run-in they may be re-screened 6 weeks after recovery from the exacerbation * Participants who have ever required intubation for a severe asthma attack/exacerbation * Participants with a history of chronic lung diseases other than asthma, including (but not limited to) sarcoidosis, interstitial lung disease, cystic fibrosis, clinically significant bronchiectasis and active tuberculosis * Participants with Type I diabetes or uncontrolled Type II diabetes * Participants who have a clinically significant laboratory abnormality as per investigator judgement before the end of run-in * Participants with a history of myocardial infarction (this should be confirmed clinically by the Investigator) within the previous 12 months * Participants with a history of long QT syndrome or a family history of a first degree relative with sudden cardiac death under the age of 50 years, or participants whose QTc measured at run-in or at baseline (prior to randomization) (Fridericia method) is prolonged (\> 450 msec for males and \> 460 msec for females) and confirmed by a central assessor or the inability to determine the QT interval corrected by Fridericia's formula (QTcF) interval (these participants should not be re-screened) * Female participants of childbearing potential defined as all females physiologically capable of becoming pregnant (e.g. are menstruating) who do not agree to abstinence or, if sexually active, do not agree to the use of contraception as defined in the exclusion criteria * Use of long-acting muscarinic antagonist (LAMA) within 3 months prior to screening Other protocol-defined inclusion/exclusion criteria may apply.