Role of ITPA and SLC28A2 genes in the prediction of anaemia associated with protease inhibitor plus ribavirin and peginterferon in hepatitis C treatment.

BACKGROUND

Anaemia is a common side-effect of ribavirin (RBV) use that overwhelms management of hepatitis C when protease inhibitors are added.

OBJECTIVE

To assess the pharmacogenomic impact of candidate genes SLC28A2, SLC28A3 and ITPA on anaemia in patients receiving triple therapy.

METHODS

Patients (n=161) with chronic hepatitis C genotype 1 treated with telaprevir (n=95) or boceprevir (n=66) were included. Using RT-PCR we genotyped ITPA (rs1127354, rs7270101) and SLC28A3 (rs56350726, rs10868138) and SLC28A2 (rs11854484). Clinically significant anaemia (CSA) was diagnosed when at least one of the following criteria was observed: (a) haemoglobin <8.5g/dL during treatment; (b) blood transfusion required; (c) erythropoietin administered.

RESULTS

CSA occurred in 44% (69/157) of patients and was associated with SLC28A2 rs11854484 [CC/CT genotypes: 33% (26/78) vs. TT genotype: 56% (36/64); p=0.006]. Further, the needed for blood transfusion was related to genotype [CC: 0% (0/18) vs. CT: 13% (8/61) vs. TT: 27% (17/64); p=0.016]. Similarly, ITPA rs1127354 genotypes [AA/AC: 19% (3/16) vs. CC: 45% (61/135; p=0.060] were linked to CSA. In multivariate analysis, SLC28A2 rs11854484 TT genotype (OR:2.33;95%CI:1.10-4.95; p=0.027), female sex (OR:2.54;95% CI:1.13-5.71;p=0.024) and Hb drop at week 4) OR: 1.36; 95CI%: 1.11-1.67; p=0.003) were independently associated with CSA. Similarly, ITPA rs1127354 genotypes [AA/AC: 16% (3/19) vs. CC: 63% (85/134); p=0.0001] and ITPA rs6051702 genotypes [CC/CA: 46% (26/57) vs. CC: 65% (60/93); p=0.023] were related to Hb drop of >3g/dL at week 4.

CONCLUSIONS

In patients receiving first generation protease inhibitors, genotype SLC28A2 rs11854484 predicts CSA, and helps to identify a subgroup of patients with better tolerance of triple therapy.