Cirtuvivint (SM08502) is a potent and orally active inhibitor of CDC-like kinase (CLK) and a DYRK (dual-specificity tyrosine kinase) that targets mRNA splicing and is optimized for Wnt pathway inhibition. Cirtuvivint inhibits serine and arginine-rich splicing factor (SRSF) phosphorylation and disrupts spliceosome activity. Cirtuvivint can be used for solid tumor research.