This is a parallel-group, Phase 2, randomized, double-blind, placebo-controlled, 2-arm study for the treatment of asthma.

The purpose of this study is to assess the efficacy, safety, and tolerability of add-on therapy with subcutaneous (SC) lunsekimig compared with placebo in male and female participants (aged 18 to 80 years, inclusive) with asthma, who are not currently eligible for biologic treatments.

Study details include:

• The study duration will be approximately 64 weeks for participants not transitioning into the LTS study and approximately 60 weeks for participants transitioning into the LTS study.
• The investigational treatment duration will be up to approximately 52 weeks.
• The number of visits will be 18.

Inclusion Criteria:

• Physician-diagnosed mild-to-moderate asthma for more than 12 months based on GINA guidelines.
• At least 1 asthma exacerbation in the year prior to Screening (Visit 1).
• Pre-BD FEV1 of equal or more than 40% of predicted normal (by Global Lung Function Initiative [GLI] standards) at Screening (Visit 1).

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

• Other severe lung diseases (eg, chronic obstructive pulmonary disease [COPD]. bronchiectasis, idiopathic pulmonary fibrosis, etc) which may impair lung function.
• Participants who experience a deterioration of asthma that results in emergency treatment or hospitalization, or treatment with systemic steroids within 1 month prior to the Screening (Visit 1) (counting from the date of completion of treatment for asthma exacerbation).
• Participants who have experienced an upper or lower respiratory tract infection within the 4 weeks prior to Screening (Visit 1).
• Known history of, or suspected, significant current immunosuppression, including history of invasive opportunistic or helminthic infections despite infection resolution or otherwise recurrent infections of abnormal frequency or prolonged duration.
• Evidence of any infection requiring systemic anti-infective treatment within 2 weeks before Screening (Visit 1) or during the screening period. Significant viral infections within 2 weeks before Screening (Visit 1) or during the screening period even if the participant has not received systemic antiviral treatment (eg, influenza receiving only symptomatic treatment).
• Participants with active tuberculosis (TB), latent TB, a history of incompletely treated TB, suspected extrapulmonary TB infection, or who are at high risk of contracting TB (such as close contact with individuals with active TB), or received Bacillus Calmette-Guérin (BCG)-vaccination within 12 weeks prior to Screening (Visit 1).
• Severe concomitant illness that would in the Investigator's opinion inhibit the participant's participation in the study, including for example, but not limited to, hypertension, renal disease, neurological conditions, heart failure, and pulmonary disease.

NOTE: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical study.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org