RG3039 is a small molecule inhibitor primarily investigated for its potential in treating spinal muscular atrophy (SMA). It functions by modulating the survival motor neuron 2 (SMN2) gene splicing, leading to increased production of full-length SMN protein, which is deficient in SMA patients. This compound has shown promise in preclinical studies by improving motor function and extending survival in animal models of SMA. Although further clinical development has been limited, RG3039 contributed valuable insights into SMN2-targeted therapies and supported the advancement of other SMN-enhancing drugs in the treatment of neuromuscular disorders.