X-NOVA3 Study: This is a research study comparing a new medicine called azetukalner with a placebo (a pill with no medicine) to see if it helps adults with Major Depressive Disorder (MDD). MDD is a condition where people feel very sad and lose interest in things they used to enjoy.

Key Points:

• The study lasts for up to 24 months, with several visits needed.
• Participants must be adults aged 18 to 74, with their first depression episode before age 50.
• Participants cannot have other major mood or thought disorders, and must not be pregnant or planning pregnancy.

In this study, participants will randomly receive either azetukalner or a placebo. "Randomized" means that which treatment you get is like flipping a coin. "Double-blind" means neither you nor the doctors know if you are getting azetukalner or the placebo, to keep the study fair. You may not join if you have other mental health conditions or have used certain medications recently. It’s important to understand the risks and benefits before deciding to participate. Participants will be closely monitored to ensure safety.