ITPA gene variation and ribavirin-induced anemia in patients with genotype 2 chronic hepatitis C treated with sofosbuvir plus ribavirin
Murakawa, M.; Asahina, Y.; Nagata, H.; Nakagawa, M.; Kakinuma, S.; Nitta, S.; Kawai-Kitahata, F.; Otani, S.; Kaneko, S.; Miyoshi, M.; Tsunoda, T.; Asano, Y.; Sato, A.; Itsui, Y.; Azuma, S.; Nouchi, T.; Furumoto, Y.; Asano, T.; Chuganji, Y.; Tohda, S.; Watanabe, M.
Hepatology Research the Official Journal of the Japan Society of Hepatology 47(11): 1212-1218
2017
ISSN/ISBN: 1386-6346 PMID: 28128520 DOI: 10.1002/anie.201700079
Accession: 059895335
Sofosbuvir (SOF) and ribavirin (RBV) combination therapy produces a sustained response in many patients with genotype 2 chronic hepatitis C. However, RBV-induced anemia is a troublesome side-effect that may limit this treatment. Genetic variation leading to inosine triphosphatase (ITPA) deficiency is known to protect against RBV-induced hemolytic anemia. This study aimed to evaluate the relationships between the efficacy and safety of SOF/RBV treatment and ITPA gene variants. Ninety patients with genotype 2 chronic hepatitis C treated with SOF/RBV were studied. The relationships among genetic polymorphisms of ITPA and the decline in hemoglobin levels from baseline, RBV dose reduction, and sustained virological response (SVR) rates were analyzed. Overall SVR at 12 weeks was 94.4% (85/90). Patients with the ITPA CA/AA genotypes had a lower degree of anemia throughout the therapy than those with the ITPA CC genotype. The percentage of patients requiring RBV dose reduction was significantly lower for those with the ITPA CA/AA variation, a difference even more apparent when the pretreatment hemoglobin level was <12 g/dL. The dose reduction of RBV and serum albumin level were significantly associated with SVR. Patients with the ITPA CA/AA genotype were less likely to develop anemia than those with the ITPA CC genotype and were more likely to complete SOF/RBV therapy. These results may provide a valuable pharmacogenetic diagnostic tool to predict drug-induced adverse events, particularly in patients with pre-existing anemia.