"Friendly" NRTIs or NRTI-sparing Regimens Improve Response to Hepatitis C Treatment in HIV-HCV Coinfected Patients

By Liz Highleyman

Liver toxicity is a potential side effect of some antiretroviral drugs used to treat hepatitis C. Certain nucleoside analog reverse transcriptase inhibitors (NRTI) can cause other side effect that may be of concern to HIV-HCV coinfected patients who are also receiving hepatitis C treatment.

Like ribavirin (also a nucleoside analog), AZT (Retrovir) can cause anemia, while ddI (Videx) and d4T (Zerit) can cause mitochondrial toxicity, which is associated with various manifestations including liver toxicity, lipoatrophy (fat loss in the face and limbs), and pancreatitis. The latest HIV-HCV coinfection treatment guidelines, issued earlier this year, state that ddI and ribavirin should never be used together, while AZT plus ribavirin should be avoided if possible.

In a poster presented at the 4th International AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention in Sydney, Australia (July 22-25, 2007), researchers described the results of a study evaluating the safety and virological response to anti-HCV therapy in HIV-HCV coinfected patients taking different antiretroviral regimens.

The multicenter study included 230 coinfected patients treated with pegylated interferon plus ribavirin. Patients were grouped according to their HAART regimen at baseline:

• NRTI-free (NRTI-sparing) regimens;

• Regimens containing "friendly" NRTIs (any except AZT, ddI, or d4T, for example abacavir or 3TC);

• Regimens containing AZT, ddI, or d4T.

At enrollment, 85 subjects were antiretroviral-naive (untreated for HIV), 29 were taking NRTI-free regimens (boosted double protease inhibitor regimens), 19 were taking regimens with "friendly" NRTIs, and 97 were using regimens containing AZT, ddI, or d4T. Baseline characteristics (e.g., age, sex, HCV genotype) were comparable among the groups.

Results

• Undetectable HCV viral load was observed in:

- 54.3% of antiretroviral-naive patients;
- 66% of patients on NRTI-free regimens;
- 47.8% of patients taking "friendly" NRTIs;
- 35.4% of those taking AZT, ddI, or d4T (P = 0.01).

• HCV treatment discontinuation was observed in:

- 41.9% of antiretroviral-naive patients;
- 18.5% of patients on NRTI-free regimens;
- 26.1% of patients taking "friendly" NRTIs;
- 54.2% of those taking AZT, ddI, or d4T (P = 0.003).

Conclusion

Based on these findings, the researchers concluded that HIV-HCV coinfected patients treated with NRTI-free or "friendly" NRTI antiretroviral therapy demonstrated better virological response and better tolerability with standard pegylated interferon plus ribavirin treatment compared to patients who received regimens containing AZT, d4T, or ddI.

University of Frankfurt, HIV Center, HIV Treatment & Clinical Research Unit, Frankfurt on Main, Germany; University Hospital Bonn, Department of Internal Medicine I, Bonn, Germany; Private Practice, Frankfurt on Main, Germany.

08/24/07

Reference
Khaykin, M Vogel, E Voigt, and others. Impact of different ART regimens on efficacy and safety of standard HCV treatment in HIV/HCV co-infected patients. 4th International AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention. Sydney, Australia, July 22-25, 2007. Abstract MOPEB056.