A Continuation Study of Tilrekimig in Adults With Moderate-to-Severe Long-Term Breathing Difficulty, Known by the Medical Term of Chronic Obstructive Pulmonary Disease (COPD) to Learn About This Medicine When Used for a Long Period of Time

Number and percentage of participants with treatment-emergent adverse events. An adverse event is considered treatment-emergent if it begins or increases in severity following initiation of study intervention. Events will be summarized by severity and other protocol-defined characteristics

Number and percentage of participants with treatment-emergent serious adverse events. Serious adverse events are events that meet one or more of the protocol-defined seriousness criteria.

Number and percentage of participants with treatment-emergent adverse events that lead to permanent discontinuation of tilrekimig.

Number and percentage of participants with protocol-defined clinical abnormalities in laboratory values and vitals signs. Laboratory assessments include protocol-required hematology and blood chemistry evaluations. Abnormal laboratory findings will be evaluated according to protocol-defined criteria and investigator assessment of clinical significance. Vital-sign assessments include blood pressure, pulse rate, respiratory rate, temperature, and oxygen saturation measured by pulse oximetry.

Unadjusted annualized rate of adjudicated moderate or severe exacerbations of COPD. A moderate exacerbation is an acute worsening of COPD requiring systemic corticosteroids and/or antibiotics. A severe exacerbation is an acute worsening of COPD requiring hospital admission for at least 24 hours.

Unadjusted annualized rate of adjudicated severe COPD exacerbations. A severe COPD exacerbation is an acute worsening of COPD requiring hospital admission for at least 24 hours.

Unadjusted annualized rate of COPD exacerbations requiring an emergency department visit and/or hospitalization.

Mean cumulative number of adjudicated moderate or severe COPD exacerbation events over time.

Mean cumulative number of adjudicated severe COPD exacerbation events over time.

Treatment Period 1Time from initiation of C4531015 study intervention to the first adjudicated moderate or severe COPD exacerbation. The probability of an event will be estimated using the Kaplan-Meier method.

Change from the parent-study baseline at each scheduled assessment in the following spirometry parameters: pre-bronchodilator FEV1, post-bronchodilator FEV1, pre-bronchodilator FEV1/FVC ratio, and post-bronchodilator FEV1/FVC ratio. FEV1 is the forced expiratory volume in 1 second, and FVC is the forced vital capacity. Spirometry will be performed using standardized equipment and procedures. Post-bronchodilator measurements will be obtained following administration of a short-acting bronchodilator in accordance with the protocol. FEV1 will be reported in liters, and FEV1/FVC will be reported as a ratio.

Change from the parent-study baseline in SGRQ total score at each scheduled assessment. The SGRQ contains 50 items assessing symptoms, activity, and impacts on daily life. Total scores range from 0 to 100, with lower scores indicating better quality of life.

Change from the parent-study baseline in CAT total score at each scheduled assessment. The CAT contains 8 items scored from 0 to 5. The total score ranges from 0 to 40, with higher scores indicating worse health.

Change from the parent-study baseline in weekly use of short-acting bronchodilator medication at each protocol-specified assessment. Use of the bronchodilator administered solely for post-bronchodilator spirometry is excluded.

Percentage of participants classified as SGRQ responders at each scheduled assessment. A responder is a participant with an improvement of at least 4 points from the parent-study baseline in SGRQ total score. An improvement corresponds to a reduction in the total score.

Percentage of participants classified as CAT responders at each scheduled assessment. A responder is a participant with an improvement of at least 2 points from the parent-study baseline in CAT total score. An improvement corresponds to a reduction in the total score.

Unadjusted annualized rate of adjudicated moderate or severe COPD exacerbations in participants with a blood eosinophil count of at least 300 cells/µL at the parent-study baseline

Change from parent-study baseline in pre-bronchodilator FEV1; change from parent-study baseline in post-bronchodilator FEV1 in participants with a blood eosinophil count of at least 300 cells/µL at the parent-study baseline

Unadjusted annualized rate of adjudicated moderate or severe COPD exacerbations over the participant's full period of study participation.

Unadjusted annualized rate of adjudicated severe COPD exacerbations over the participant's full period of study participation.

Unadjusted annualized rate of COPD exacerbations requiring an emergency department visit and/or hospitalization.

Mean cumulative number of adjudicated moderate or severe COPD exacerbation events over time.

Mean cumulative number of adjudicated severe COPD exacerbation events over time.

Change from parent-study baseline in CAT total score in participants with a blood eosinophil count of at least 300 cells/µL at the parent-study baseline

Change from the corresponding parent-study baseline at each protocol-specified assessment in the following spirometry parameters: pre-bronchodilator FEV1, post-bronchodilator FEV1, pre-bronchodilator FEV1/FVC ratio, and post-bronchodilator FEV1/FVC ratio. FEV1 is forced expiratory volume in 1 second, and FVC is forced vital capacity. Spirometry will be performed using standardized equipment and procedures. Post-bronchodilator measurements will be obtained after administration of a short-acting bronchodilator in accordance with the protocol. FEV1 will be reported in liters and FEV1/FVC as a ratio.

Change from the parent-study baseline in SGRQ total score at each scheduled assessment after Week 52 of TP1. Scores range from 0 to 100, with lower scores indicating better quality of life.

Change from the parent-study baseline in CAT total score at each scheduled assessment after Week 52 of TP1. Scores range from 0 to 40, with higher scores indicating worse health.

Change from parent-study baseline in Saint George's Respiratory Questionnaire total score in participants with a blood eosinophil count of at least 300 cells/µL at the parent-study baseline

Change from the parent-study baseline in weekly use of short-acting bronchodilator medication at each scheduled assessment after Week 52 of TP1.

Percentage of participants with an improvement of at least 4 points from the parent-study baseline in SGRQ total score at each scheduled assessment after Week 52.

Percentage of participants with an improvement of at least 2 points from the parent-study baseline in CAT total score at each scheduled assessment after Week 52.

Time from initiation of C4531015 study intervention to the first adjudicated moderate or severe COPD exacerbation. The probability of an event will be estimated using the Kaplan-Meier method.