The immediate impact of the reverse stock split announcement on Avenue Therapeutics' share price is negative, as evidenced by the trading lower. Reverse stock splits can be perceived negatively by the market as they often signal that a company is trying to meet stock exchange minimum price requirements or improve its image, which might not address underlying financial or operational challenges. However, the long-term impact could vary depending on how the market interprets the company's financial health and strategic direction post-split.