This study is trying to identify the right dose of a long-acting medicine called WIN378 for people with moderate or severe asthma. WIN378 blocks the action of a protein called TSLP which causes inflammation in the lung and may contribute to your asthma control and symptoms. The study will test how doses of WIN378 are handled by your body (pharmacokinetics) and assess the safety of the medicine and will assess markers of asthma inflammation in your breath and in your blood, lung function and asthma control (pharmacodynamics).

This is a Phase 2, multicenter, randomized, double-blind, placebo-controlled, dose-ranging study to evaluate the safety, tolerability, efficacy and pharmacokinetics of WIN378 in adult participants with moderate to severe asthma. Participants will continue their standard background asthma therapy according to GINA Steps 3-5. Eligible participants will be randomized to receive WIN378 or placebo administered subcutaneously over a 48-week treatment period, followed by a 12-week safety follow-up.

Inclusion Criteria:

• Written Informed Consent Form
• Females that are not pregnant or breastfeeding with following condition: not a woman of childbearing potential or woman of childbearing potential using a highly effective contraception method
• Physician-diagnosis of asthma and documented evidence of airway reversibility during prior 24 months or during screening
• Airflow limitation as indicated by pre-BD FEV1 value of ≥ 30% and ≤ 90%, predicted at two visits at Screening
• Low, medium-, or high-dose ICS and ≥1 maintenance asthma controller medication (LABA/LTRA/LAMA/chromones/theophylline)

Exclusion Criteria:

• Participants with a known, pre-existing, clinically important lung condition other than asthma
• Active tuberculosis or treatment required for tuberculosis within 12 months
• Current or former smokers ≥10 pack years
• History of cancer
• Receipt of any marketed biologic agent within 4 months or 5 half-lives prior to screening; receipt of immunoglobulin or blood products within 30 days prior to screening or during the Screening Run-in period; receipt of any live or attenuated vaccines within 15 days prior to screening
• Helminth infection within 24 weeks prior to screening
• Use of immunosuppressive medication within 3 months prior to Screening Visit or during the Screening Run-in period
• Participants who are pregnant, lactating or breastfeeding

Double-blind