The purpose of this Phase III, multicentre, randomized, double-blind, single-dose, 2-period, crossover study is to assess the efficacy and safety of PT027 (budesonide/albuterol sulfate) metered-dose inhaler compared with placebo on exercise-induced bronchoconstriction in adult patients with asthma. Subjects will receive each study treatment on separate visits and undergo a treadmill exercise challenge test so that the effect of study treatment on exercise-induced bronchoconstriction can be evaluated

Inclusion Criteria:

1. Female or male aged 18 to 70 years at the time of informed consent.

2. Documented history of asthma for at least 6 months prior to Visit 1

3. Receiving 1 of the following asthma therapies with stable dosing for at least the 4 weeks before Visit 1 (no other asthma therapies are permitted during the study):

   • Short-acting β 2-adrenoreceptor agonist (SABA) used as needed;
   • Low- to medium-dose maintenance therapy with inhaled corticosteroid (ICS) and SABA used as needed.

4. Demonstrate acceptable MDI administration technique (use of a spacer device during the treatment phase is not permitted)

Exclusion Criteria:

1. Chronic obstructive pulmonary disease or other significant lung disease (eg, chronic bronchitis, emphysema, bronchiectasis with the need of treatment, cystic fibrosis, bronchopulmonary dysplasia), including regular or occasional use of oxygen.
2. Systemic corticosteroids (SCS) use (any dose and any indication) within 3 months before Visit 1.
3. History of life-threatening asthma, defined by past intubations for asthma, or intensive care unit admission for asthma within the prior 24 months.
4. Receiving regular maintenance treatment with prohibited anti-inflammatory or long-acting bronchodilator asthma medication (inhaled, nebulized, oral, or systemic) within 1 month prior to Visit 1.
5. Unable to tolerate the lung function testing performed after exercise challenge test without use of rescue medication.
6. Current smokers, former smokers with >10 pack-years history, or former smokers who stopped smoking <6 months before Visit 1 (including all forms of tobacco, e-cigarettes [vaping], and marijuana).
7. Completed treatment for lower respiratory infection within 6 weeks prior to Visit 1, regardless if resulting in accompanying asthma symptoms aggravation or not.
8. Upper respiratory infection involving antibiotic treatment not resolved within 7 days prior to Visit 1.
9. Received any marketed (eg, omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab) or investigational biologic within 3 months before Visit 1, or any other prohibited medication.
10. Historical or current evidence of a clinically significant disease.
11. History of psychiatric disease or intellectual deficiency.
12. Having a scheduled or planned hospitalization during the study.
13. Inability (and/or unwillingness) to abstain from protocol-defined prohibited medications during the study.
14. Use of any herbal products by inhalation or nebulizer within 2 weeks of Visit 1 and/or the unwillingness to stop during the study duration.
15. Significant abuse of alcohol or drugs.