This research study is looking at a new investigational treatment for adults with moderate to severe asthma. The purpose of the study is to better understand its safety and how well it may help reduce airway inflammation, improve lung function, and control asthma symptoms when added to standard asthma medications. Participants will be randomly assigned to receive either the investigational treatment or a placebo, given as injections about every six months, and will be followed for just over one year.