Risk factors for severe anaemia during telaprevir-based triple therapy: is acquired renal dysfunction the missing link?

Analysis of renal function during telaprevir-based triple therapy for chronic hepatitis C

Telaprevir (TVR) is used for the treatment of chronic hepatitis C in a combination therapy with pegylated-interferon and ribavirin. Although renal dysfunction is one of the critical adverse outcomes of this treatment, little is known regarding the mechanism of its onset. The present study assessed the association of renal function with TVR dose and viral response. Hematological, biochemical, urinary and virological parameters of renal function were examined during the TVR-based triple therapy of patients infected with hepatitis C virus (HCV) genotype 1b. Serum creatinine levels were increased and the estimated glomerular filtration rate (eGFR) was decreased in every patient during TVR administration, but these values recovered to normal levels following cessation of TVR. Fractional excretion of sodium was <1% at days 3 and 7, appearing similar regardless of baseline renal function. Urinary β₂-microglobulin levels were elevated and were significantly higher in patients with renal dysfunction, as compared with those not exhibiting renal dysfunction (P<0.05). The reduction in renal function was milder in patients treated with a reduced TVR dose, and these patients had a significantly lower risk of developing renal dysfunction (P<0.05). Using a multivariate analysis, TVR dose and eGFR at the initiation of treatment were identified as significant contributory factors in the development of renal dysfunction. Reduction in TVR dose did not lead to a significant increase in the viral kinetics of HCV or detrimental effects on the sustained viral response (SVR) rate. It is hypothesized that renal dysfunction during TVR treatment is caused by damage of the renal tubule, in addition to pre-renal dysfunction, and that reduction in TVR dose reduces the rate of renal dysfunction without causing a significant decrease in the SVR rate.

eGFR decrease during antiviral C therapy with first generation protease inhibitors: a clinical significance?

BACKGROUND & AIMS

Renal toxicity of first generation protease inhibitors (PIs) was not a safety signal in phase III clinical trials, but was recently reported in recent studies. It appeared important to determine the clinical significance of these findings.

METHODS

We retrospectively analysed 101 HCV patients receiving triple therapy with telaprevir (n = 36) or boceprevir (n = 26) or double therapy (n = 39) with peginterferon and ribavirin and having a close monitoring of eGFR (MDRD formula) during and after treatment. EGFR decline over time was assessed by a linear mixed-effects model (LMEM) with search for possible explanatory covariates.

RESULTS

Patients treated with telaprevir presented a significant decrease of eGFR with the same kinetics: initial decrease at W (week) 4, nadir at W8 (mean decrease 17.0 ± 18.9 ml/min/1.73 m(2)) and return to baseline at W16. The W8 eGFR was correlated with the D0 eGFR (R(2) = 0.49). The LMEM showed that interindividual variability in the slope of eGFR vs time between D0 and W8 was non-significant and eGFR nadir could be predicted from eGFR obtained at D0. In multivariate analysis, eGFR intercept (i.e. baseline value) was associated with older age and male sex.

CONCLUSION

The eGFR significantly varied in telaprevir group only. Our model showed that eGFR nadir mainly depended on initial eGFR. As telaprevir has been shown to inhibit mostly the drug transporter OCT2 which interacts with creatinine transport, the early decrease of eGFR observed could be a benign phenomenon. However, as unpredictable true renal toxicity may occur during therapy, we recommend a thorough follow-up of eGFR.