CBR3 and heart failure: Our findings are consistent with evidence from kinetic studies - i.e., CBR3 V244 (G allele) has higher catalytic activity for anthracycline substrates than CBR3 M244 (A allele) - and a pharmacokinetic model of myocardium exposure which suggest that patients with CBR3 GG genotype treated with DOX have a higher simulated risk of heart failure [30, 31].