A Study to Learn About the Study Medicine Called Tilrekimig ( PF-07275315) in People With Severe Asthma

The purpose of this clinical study is to learn about the safety and effects of the study medicine (called tilrekimig) for the potential treatment of severe asthma. Asthma is a condition that makes it challenging to breathe, which negatively impacts the quality of life of people who are affected. The study is seeking participants who: * Have a history of severe asthma for at least 12 months * Have had at least 2 asthma attacks (also known as exacerbations) within the last 12 months All participants will be given shots of study medicine or a placebo at the study clinic. Tilrekimig or the placebo will be given about every 4 weeks during the study. The study will compare the experiences of people receiving tilrekimig to those people who receive the placebo. This will help determine if tilrekimig is safe and effective.

Inclusion Criteria Must meet the following asthma criteria: 1. History of persistent, severe asthma for at least 12 months prior to screening as defined by recognized international and / or local guidelines. 2. Must have experienced at least 2 asthma exacerbations requiring treatment with systemic steroids (oral or parenteral) for 3 consecutive days or more; an emergency room or urgent care visit (\10% of the participant's predicted value at 15 - 30 minutes (or as consistent with local treatment practices) after inhaling 400 µg of salbutamol/albuterol (or equivalent SABA) at least once for spirometry conducted during screening period. Other Inclusion Criteria: 4. Maintenance treatment of a medium-to-high dose ICS plus an additional controller (eg, LABA) consistent with current GINA and / or local guidelines for at least 12 months (and on a stable dose for 3 months prior to screening). Exclusion Criteria Participants are excluded from the study if any of the following criteria apply: Medical Conditions: 1. Evidence of lung disease(s) other than asthma, either clinical evidence, spirometry, or imaging (Chest X-ray, CT, MRI) within 12 months of the screening visit, as per local standard of care, including but not limited to, chronic obstructive pulmonary disease, other emphysematous lung disease such as alpha-1 antitrypsin disease, cystic fibrosis, emphysema, pulmonary fibrosis, Churg-Strauss syndrome, allergic bronchopulmonary aspergillosis, sarcoidosis, pulmonary embolism. 2. Any psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years that may increase the risk of study participation or, in the investigator's judgement, make the participant inappropriate for the study. Prior/Concomitant Therapy: 3. Use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s). Treatment with any dose level of systemic (oral, intraarticular, or injectable) corticosteroids within 28 days of the screening visit. 4. Prior or concurrent treatment with either approved or experimental biologic treatment (such as inhibitors of IL-4Ralpha, TSLP, OX40/OX40L, IL-13, IL-33 / ST2) or targeted synthetic drugs for the treatment of asthma or other type 2 inflammatory diseases, including but not limited to: AD, EoE, CRS. 5. Prior (within 12 weeks prior to Screening Visit 1) or planned concomitant treatment with immunoglobulin supplementation (eg, IV Ig or SC Ig). 6. Bronchial thermoplasty within the previous 24 months. Prior/Concurrent Clinical Study Experience: 7. Administration of an investigational drug product within 30 days or 5 half lives preceding the screening visit (whichever is longer). Previous participation in other tilrekimig studies or participation in studies of other investigational products (drug or vaccine) at any time during this study.