The transmembrane transport of JPH203 was demonstrated to be mediated by transporters of the organic‐anion‐transporting peptides (OATP, SLCO) and the organic anion transporters (OAT, SLC22) families, namely OATP1B1, OATP1B3, OATP2B1 and OAT3.35 Interestingly, some of these transporters were also described to be expressed in brain capillary endothelial cells constitutive of the blood‐brain barrier (BBR).36 This suggests that a route for JPH203 to cross the BBR could be provided by transmembrane transporters, making brain tumours accessible to this compound. This evidence concerns the gene SLCO1B1 and brain neoplasm.