**Study Overview:** This clinical study is testing a medicine called **DA-1229 (Evogliptin)** for people with a heart condition known as **calcific aortic valve disease** and **mild to moderate aortic stenosis**. Aortic stenosis is when a heart valve doesn't open fully, making it hard for blood to flow. The study will last for about **112 weeks** (over two years) and involves taking the medicine or a placebo (a pill with no active medicine) once a day. **Phases of the Study:** 1. **Screening Period:** Up to 4 weeks to check if you qualify. 2. **Treatment Period:** 104 weeks of taking the medicine or placebo. 3. **Follow-Up Period:** 2-4 weeks to monitor after treatment ends. **Eligibility:** You must be 35 years or older, have mild to moderate aortic stenosis, and meet other specific health criteria. Some health conditions or medicines may prevent you from joining. **Key Points to Consider:** - **Duration:** The study lasts over 2 years. - **Commitment:** Regular check-ups and taking study medicine daily. - **Safety:** Always consult your doctor, especially if you have diabetes or other health issues. **Note:** You can withdraw from the study at any time if you decide to.