Study of Safety of CSJ117 in Participants With Moderate to Severe Uncontrolled Asthma

This is a 12/24-week Phase llb, multicenter, multi-national, double-blind, randomized, parallel-arm, placebo-controlled extension study to evaluate the safety and tolerability, pharmacokinetics and immunogenicity of 5 dose levels of CSJ117 in adult asthma participants treated with medium or high dose ICS plus LABA alone or with additional asthma controllers (allowed: LTRA, LAMA, theophylline or its derivatives), who have completed the prior core phase llb study CCSJ117A12201C (NCT04410523). The study will include the following three parts: A Screening period of up to 3 days to assess eligibility. A Treatment period of 12 or 24 weeks. There are two scenarios on when a participant can enroll into the extension study depending on when the study site is activated for the extension study CCSJ117A12201E1: * A 24 week treatment period: Participants on each of the five treatment arms (CSJ117 0.5 to 8 mg) or placebo of the core study CCSJ117A12201C, who will enter the extension study after the last Treatment period visit (week 12) of the core study, will be randomized in a 1:1 ratio to continue on their previously assigned CSJ117 dose or placebo from CCSJ117A12201C for 24 weeks, or to first go through a 12-week "washout period" receiving placebo (for the blinding purpose) and then restart on their previously assigned CSJ117 dose or placebo from CCSJ117A12201C for 12 weeks. * A 12 week treatment period: Participants on each of the five treatment arms (CSJ117 0.5 to 8 mg) or placebo of the core study CCSJ117A12201C, who will enter the extension study after the last Follow-up visit (week 24) of the core study, will restart on their previously assigned CSJ117 dose or placebo from CCSJ117A12201C for 12 weeks. A Follow-up period of 12 weeks, study drug free, following the last dose of study drug.