This study is testing a new medicine called **varoglutamstat (PQ912)** for early Alzheimer's disease (AD). Alzheimer's is a brain disease that affects memory and thinking. **Varoglutamstat** is a pill taken twice a day. The study will see if it helps people think better and if it's safe. The study has two parts: **Phase 2A** and **Phase 2B**. In Phase 2A, researchers will try three different doses for at least 24 weeks to find the best and safest one. About 180 people will join. If Phase 2A goes well, Phase 2B will include more people (414) to see if the medicine works over a longer time. **Key Points for Participants:** - **Duration:** The study has a minimum duration of 24 weeks. - **Visits:** Participants will be randomized and must attend regular clinic visits with a study partner. - **Safety:** The study will check for any side effects and ensure the medicine is safe. Eligible participants should be aged 50-89, have mild AD or mild cognitive impairment, and need a supportive study partner. People with other serious brain diseases or certain health issues cannot join.