TK-98

TK-98 is a small molecule calpain inhibitor developed by researchers at Tohoku University with support from the Japan Agency for Medical Research and Development (AMED). It is being developed as a neuroprotective therapy for retinitis pigmentosa (RP), a group of genetic disorders characterized by the progressive degeneration of photoreceptor cells. The drug's mechanism of action involves the inhibition of calpains, which are calcium-dependent cysteine proteases. In the context of RP, the overactivation of calpains—triggered by excessive calcium influx—leads to the proteolytic degradation of cellular components and the induction of apoptosis in photoreceptors. By inhibiting these enzymes, TK-98 aims to prevent cell death, preserve retinal structure, and slow the loss of visual function. It is typically administered via intravitreal injection to provide localized treatment to the retina.