In 2025, innovation in drug development remained stable, with the proportion of first-in-class drugs continuing to increase. The Center for Drug Evaluation and Research (CDER) of the US Food and Drug Administration (FDA) approved a total of 46 new drugs in the past year, including 34 new molecular entities (NMEs) and 12 biologics license applications (BLAs). The number of approvals slightly decreased compared to the previous three years. This year, 31 small molecule drugs were approved, accounting for 67% of the total, among which 13 were first in class small molecule drugs. The treatment areas covered rare diseases, oncology, autoimmune diseases, respiratory diseases, and more. Several first in class small molecule drugs have breakthrough clinical value, such as the world's first non-opioid analgesic drug, NaV1.8 inhibitor suzetrigine, the first approved local TRPM8 receptor agonist acoltremon for dry eye disease, the first targeted mitochondrial inner membrane cardiolipin elamipretide, the first approved selective phosphodiesterase 4B (PDE4B) inhibitor nerandomilast for idiopathic pulmonary fibrosis (IPF), and the first selective oral Menin-MLL inhibitor iftomenib. First in class drugs have significant clinical, academic, and commercial value and have attracted extensive attention from patients, researchers and enterprises. This article briefly analyzes the research background, process and therapeutic applications of three representative first in class small molecule drugs from the perspective of medicinal chemistry, with the aim of providing more research directions and methods for the development of first in class drugs.