FDA approvals are critical milestones for pharmaceutical companies, often leading to significant positive movements in their stock prices. The approval of Rezdiffra by the FDA is a strong validation of Madrigal Pharmaceuticals' research and development capabilities, likely enhancing its reputation in the market and attracting investor interest. Given the importance of such regulatory approvals for the commercial success of new drugs, this news is expected to have a positive short-term impact on MDGL's stock price.