The purpose of the study is to help doctors learn more about investigational dupilumab (the study drug) and to find out how safe it is and how well it works for patients with asthma. The study will investigate whether the study drug can help to improve the health of your lungs, reduce the inflammation in your airways and also improve your quality of life. If you join the study, your participation will last a minimum of 29 weeks and up to 41 weeks and is planned to include approximately 153 participants. The study will be conducted worldwide. If the study is suited for you, you will be randomized by chance (like drawing straws) to receive either the study drug (300 mg dupilumab) or placebo.