Treatment of HIV/HCV Coinfection With Peg-IFN and Ribavirin in Patients Receiving ART Monotherapy With Lopinavir/r

Viral hepatitis, mainly when caused by the hepatitis C virus (HCV), is highly significant in the setting of infection by the human immunodeficiency virus (HIV) because high activity antiretroviral therapy (HAART) has a very favorable impact upon morbidity and mortality of this disease. HAART has achieved disease control, significantly increasing survival and improving the quality of life of subjects with HIV infection.

Spain has one of the highest prevalences of HIV-HCV co-infection because both HCV and HIV infection are strongly associated to being or having been an intravenous drug user (IDU); thus, from 61% to 69% of these subjects infected by HIV in Spain are also infected by HCV.

From 1998, standard treatment for chronic C hepatitis consists of the combination of interferon alpha and ribavirin, based on an increased efficacy versus interferon monotherapy; however, development of pegylated interferon, with a more convenient bioavailability as compared to conventional interferon alpha, has allowed for developing even more effective combined therapies and the possibility of improving response prediction based on changes in viremia within the first few weeks of treatment. However, treatment of HCV infection usually involves severe side effects, which often lead to treatment discontinuation or to the need for adjusting drug dosage, in which case treatment efficacy may decrease.

HCV+ subjects who, because of HIV co-infection, should also receive HAART, may have an increased number or increased severity of adverse reactions due to interactions occurring with drug co-administration.

Lopinavir/ritonavir (LPV/r) is a potent HIV protease inhibitor and is characterized by a very high pharmacological and genetic barrier.

Different studies (subject cohorts, uncontrolled studies) during the past years have appeared in the literature showing the efficacy of LPV/r or controlling viral replication.

Most studies were conducted with the soft gel capsule formulation of LPV/r. In this study, the new formulation of LPV/r (Kaletra) as tablets approved by the FDA and EMEA (Spain authorization 30th Oct 2006) will be used. This new formulation will provide additional benefits to this strategy that has only been studied to date with soft gel capsules.

Based on the foregoing and on the additional cost savings involved in this strategy, we think that LPV/r, as single antiretroviral agent concomitantly administered with treatment for hepatitis C virus infection may provide significant benefits because it would prevent interactions between NRTIs and ribavirin, thus being potentially able to decrease the adverse events derived from mitochondrial toxicity and minimizing the possibility of anemia. In addition, replacement of NNRTIs by LPV/r may significantly decrease CNS involvement that may be enhanced by co-administration of efavirenz and peg-interferon, or minimize the risk of hepatotoxicity caused by nevirapine.