Correlation of C609T Polymorphism of Nadph Quinone Oxidoreductase 1 and Hematological Toxicities in Lung Cancer Patients Treated With Amrubicin

Background Amrubicin hydrochloride (AMR) is a novel synthetic aminoanthracycline derivative, that is metabolically activated to amrubicinol (AMR-OH) by carbonyl reductase. The cytotoxic activity of AMR-OH is promising for small cell lung cancer and considered as a key agent. NADPH Quinone Oxidoreductase 1 (NQO1) is a cytosolic flavoprotein that metabolizes the quinone structures contained in both AMR and AMR-OH. NQO1 expression genotyped homozygous for minor alleles (T/T) was low compared with homozygous for major alleles (C/C) or heterozygous (C/T). We hypothesized that NQO1 C609T polymorphisms may relate to the AMR pharmacokinetics and clinical outcomes. Methods The patients with lung cancer received AMR at a dose of 30 or 40mg/m2/day on day 1-3 at Osaka City University Hospital were enrolled. Plasma sampling was performed at the time points of 24h after the third AMR injection. The concentrations of AMR and AMR-OH were determined by HPLC method. NQO1 C609T polymorphism was assayed using real-time polymerase chain reaction methods. Results A total of 35 patients were enrolled. The C/C, C/T, and T/T were observed in 12 (34.3%), 16 (45.7%), and 7 (20%) patients, respectively. A dose of 30 mg/m2 was administered to 19 patients, and 40mg/m2 was administered to 16 patients. The mean plasma concentrations of AMR-OH on day4 at a dose of 30mg/m2 and 40mg/m2 were 11.02 ± 3.83 and 16.18 ± 6.17 ng/ml, respectively (p = 0.005). In patients with AMR at a dose of 40mg/m2, the plasma concentrations of AMR-OH on day4 exhibited a tendency toward a relationship with NQO1 genotypes with values of C/C 20.5 ± 5.89, C/T 15.9 ± 5.43, and T/T 11.2 ± 4.47ng/ml (p = 0.066). The C/C was related to decrease changes in WBC, hemoglobin, and platelet counts (p = 0.01, p = 0.03, and p = 0.0005, respectively). No significant correlations were observed between NQO1 genotypes and clinical outcomes at a dose of 30mg/m2. Conclusions NQO1 C609T polymorphism had a tendency of correlation with the plasma concentrations of AMR-OH, and thereby had significant correlations with hematologic toxicities. NQO1 genotype appears to be the candidate biomarker of hematological toxicities of AMR treatment at a dose of 40mg/m2. Disclosure All authors have declared no conflicts of interest.