The submission of a New Drug Application to the FDA is a significant step forward for Eton Pharmaceuticals and its product ET-400. This move indicates progress in the company's pipeline and has the potential to positively impact its stock price in the short term. Investors often view such regulatory milestones positively, as they bring the company closer to generating revenue from the new product. However, the actual impact on the stock price will depend on the market's perception of the drug's potential success and the company's ability to successfully navigate the approval process.