The TSUBAKI study, initiated in 2015, was a placebo-controlled, double-blind, Phase 2 clinical study conducted to evaluate the safety and efficacy of bardoxolone methyl in Japanese patients with DKD having no risk factors for heart failure, that is, excluding high BNP levels (> 200 pg/mL) at baseline or a history of heart failure. This evidence concerns the gene NPPB and heart failure.