The main purpose of this study is to support the dose selection for future Phase III clinical trials by evaluating efficacy and safety of four MIJ821 doses (very low, low, high and very high) administered every other week by intravenous infusion on top of pharmacological antidepressant treatment, compared with placebo, for the rapid reduction of the symptoms of MDD in participants who have suicidal ideation with intent. In addition, the study will explore the effect of single dose administration of very high and high doses to treat MDD in participants who have suicidal ideation with intent.~The study consists of three periods: a Screening Period (up to 48 hrs), a double-blind Core Period (6 weeks) and Extension Period (up to 52 weeks). The Extension Period will explore durability of the effect of the study treatment and the effect of MIJ821 on relapse rate, as well as safety of repeated MIJ821 administration.~All patients in the extension period will receive active treatment.
Study of efficacy and safety of MIJ821 in addition to comprehensive standard of care on the rapid reduction of symptoms of Major Depressive Disorder (MDD) in subjects who have suicidal ideation with intent