Hepatitis C and HIV coinfection

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In HIV–HCV co-infected patients, the hepatitis C (HCV) viral load is higher than in HCV-mono-infected patients in both the plasma and liver tissue. Patients who are HIV-positive are commonly co-infected with HCV due to shared routes of transmission: percutaneous exposure to blood, sexual intercourse, and from a mother to her infant. Infection with HCV can be asymptomatic, self-limiting, or progress to cirrhosis or cancer.

Characteristics[edit]

The morbidity and mortality caused by HCV has increased since the inception of highly active antiretroviral therapy (HAART) because HIV patients are living longer from potent antiretroviral therapies and prophylaxis of traditional opportunistic infections. The effect of HCV on the natural history of HIV remains inconclusive due to contradictory studies documenting no effect, while others show an increase to an AIDS defining illness or death. In the United States, approximately 150,000 to 300,000 people are co-infected with HIV and HCV. This represents 15% to 30% of all HIV infected patients and 5% to 10% of all HCV patients. Reduced HCV antibody production, drug interactions, other causes of liver disease, differing epidemiologic characteristics and natural history complicate the management of HCV/HIV patients. Until recently there was little data published regarding treating HIV–HCV co-infected patients; fortunately recent trials have been published about the safety and efficacy of current treatment options.

Treatment[edit]

The primary objective of HCV therapy is permanent eradication of the virus. The secondary potential benefit of eradication is a reduction in the risk of liver failure and liver cancer. Currently, peginterferon alfa-2a plus ribavirin is the only FDA approved treatment for HIV–HCV co-infected patients. Interferons bind to specific cell surface receptors of virus-infected cells, which induces a complex cascade of protein-protein interactions and a rapid activation of gene transcription. The antiviral effects of interferons are mediated through inhibition of viral penetration or uncoating, inhibiting viral replication or translation of viral proteins, and/or viral assembly and release. The difference between peginterferon and interferon is the addition of a polyethylene glycol (PEG) polymer. The addition of PEG decreases plasma clearance considerably, protects the molecule from proteolytic degradation and reduces its immunogenicity. Peak concentrations are approximately 1.5–2 fold higher than trough concentrations and the half-life is 80 hours (compared to 5.1 hours for interferon alpha-2a). Ribavirin is a synthetic nucleoside analogue, but its mechanism of action is not clearly established. Ribavirin inhibits the replication of a wide range of RNA and DNA viruses. Pharmacokinetics are similar in patients with HIV co-infection compared with HCV mono-infection.

Pegylated Interferon Alfa-2B (Peg Intron) plus Ribavirin versus Standard Interferon Alfa-2B (Intron A) plus Ribavirin[edit]

This was a randomized, phase 3, open-label, parallel group study. Four hundred sixteen treatment naïve patients were assigned to 1.5 µg/kg peginterferon alfa-2b once weekly plus ribavirin 800 mg daily or 3 million units of standard interferon alfa-2a plus ribavirin 800 mg daily for 48 weeks. 6 Patients were evaluated at weeks 2 and 4, then every 4 weeks after treatment and then at weeks 4, 12, and 24 post-treatment until week 72 was reached. The primary end-point was a sustained viral response (SVR), defined as undetectable serum HCV-RNA at week 72. The secondary endpoint was histological improvement. In the standard interferon group, 20% of the 207 patients obtained an SVR, and in the peginterferon group 27% of the 205 patients (p=0.047) obtained an SVR. At week 24, undectable HCV RNA levels were achieved in 28% and 40% of patients, respectively (p=0.004), respectively. At 48 weeks, the end of treatment virologic responses were 21% and 35% of their respective groups (p=0.001). In patients who had genotype 1 or 4, peginterferon achieved a higher rate of SVR (17%) than interferon (6%) p=0.006. However, in genotypes 2, 3 or 5, the rates of SVR were similar. The withdrawal and adverse event rates were similar.

Pegylated Interferon Alfa-2A (Pegasys) plus Ribavirin versus Interferon Alfa-2A plus Ribavirin[edit]

In the study by Chung, et al. 66 treatment-naïve patients received 180 µg weekly of peginterferon or 6 million units thrice weekly of interferon for 12 weeks and then switched to 3 million units thrice weekly for 48 weeks.[1] Both groups received ribavirin (600 mg for 4 weeks, 800 mg for four weeks and then 1000 mg daily for the remainder of the study). The main endpoint was to detect the differences in virologic response rates between the two groups. At week 24, subjects who did not have a virologic response underwent a liver biopsy and treatment was continued in patients who showed a histological improvement.

Tolerability[edit]

In the first trial, approximately the same number of patients from each group withdrew due to laboratory abnormalities or adverse events.[2] The doses were modified more frequently in the peginterferon group due to lab abnormalities (7% vs 20%) or adverse events (7% vs 16%) (p=0.004). Neutropenia (p=0.04) and weight loss (p=0.03) were significantly higher in the peginterferon group; whereas, insomnia was higher in the interferon group (p=0.02). In the second study, 12% in each group withdrew due to lab abnormalities or adverse events.[1] Both groups experienced similar number of episodes of neutropenia, but two subjects in the peginterferon group dropped out due to grade 4 neutropenia.

The other patients were managed by dose reduction. One case of clinically significant pancreatitis occurred in a patient who was receiving didanosine. In the last study, about the same number of patients dropped out of the study due to lab abnormalities, but the patients who dropped out from adverse reactions varied.[3] Overall, most patients withdrew from the interferon plus ribavirin arm and the least from the peginterferon plus ribavirin arm.

The major difference was that there was a higher incidence of neutropenia in the peginterferon groups.

Predictors of an SVR[edit]

In the trials described above, the only common predictor of SVR among all three was the treatment of HCV other than type 1.6–8 In the trial by Chung et al., patient characteristics that predicted an SVR were treatment with peginterferon and ribavirin, absence of prior drug abuse, a detectable level of HIV-1 RNA, and a Karnofsky score of 100.[1] The Karnofsky score is a subjective measure of how well the patient is doing. A score of 100 indicates that the patient has no complaints or evidence of disease, a score of 50 indicates that the patient requires considerable assistance and frequent medical care, and a score of 0 indicates that the patient is dead. In the study by Carrat et al., no protease inhibitor therapy, an age of 40 years or younger, or a baseline alanine aminotransferase greater than three times the upper limit of normal predicted a sustained virological response.[2] In the study by Torrani et al., SVR was predicted by HCV genotype other than 1 and a baseline HCV RNA level of 800,000 IU or less per milliliter.[3]

In a study involving 21 HIV co-infected patients (DICO),[4] pre-treatment baseline plasma levels of IP-10 predicted the reduction of HCV RNA during the first days of interferon/ribavirin therapy (“first phase decline”) for HCV genotypes 1–3,[5] as is also the case in HCV mono-infected patients.[6][7][8] Pre-treatment IP-10 levels below 150 pg/mL are predictive of a favorable response, and may thus be useful in encouraging these otherwise difficult-to-treat patients to initiate therapy.[5]

Notes[edit]

References[edit]

  • Askarieh, Galia; Alsiö, Åsa; Pugnale, Paolo; Negro, Francesco; Ferrari, Carlo; Neumann, Avidan U.; Pawlotsky, Jean-Michel; Schalm, Solko W.; et al. (May 2010). "Systemic and intrahepatic interferon-gamma-inducible protein 10 kDa predicts the first-phase decline in hepatitis C virus RNA and overall viral response to therapy in chronic hepatitis C". Hepatology. 51 (5): 1523–30. doi:10.1002/hep.23509. PMID 20186843.
  • Carrat, F; Bani-Sadr, F; Pol, S; Rosenthal, E; Lunel-Fabiani, F; Benzekri, A; Morand, P; Goujard, C; et al. (December 2004). "Pegylated interferon alfa-2b vs standard interferon alfa-2b, plus ribavirin, for chronic hepatitis C in HIV-infected patients: a randomized controlled trial". JAMA. 292 (23): 2839–48. doi:10.1001/jama.292.23.2839. PMID 15598915.
  • Chung, RT; Andersen, J; Volberding, P; Robbins, GK; Liu, T; Sherman, KE; Peters, MG; Koziel, MJ; et al. (July 2004). "Peginterferon Alfa-2a plus ribavirin versus interferon alfa-2a plus ribavirin for chronic hepatitis C in HIV-coinfected persons". The New England Journal of Medicine. 351 (5): 451–9. doi:10.1056/NEJMoa032653. PMC 4113392. PMID 15282352.
  • Torriani, FJ; Rodriguez-Torres, M; Rockstroh, JK; Lissen, E; Gonzalez-García, J; Lazzarin, A; Carosi, G; Sasadeusz, J; et al. (July 2004). "Peginterferon Alfa-2a plus ribavirin for chronic hepatitis C virus infection in HIV-infected patients". The New England Journal of Medicine. 351 (5): 438–50. doi:10.1056/NEJMoa040842. PMID 15282351.
  • Falconer, K; Sandberg, JK; Reichard, O; Alaeus, A (2009). "HCV/HIV co-infection at a large HIV outpatient clinic in Sweden: feasibility and results of hepatitis C treatment". Scandinavian Journal of Infectious Diseases. 41 (11–12): 881–5. doi:10.3109/00365540903214272. PMID 19922074.
  • Falconer, K; Askarieh, G; Weis, N; Hellstrand, K; Alaeus, A; Lagging, M (July 2010). "IP-10 predicts the first phase decline of HCV RNA and overall viral response to therapy in patients co-infected with chronic hepatitis C virus infection and HIV". Scandinavian Journal of Infectious Diseases. 42 (11–12): 100824014139078. doi:10.3109/00365548.2010.498019. PMID 20608766.
  • Lagging, M; Romero, AI; Westin, J; Norkrans, G; Dhillon, AP; Pawlotsky, JM; Zeuzem, S; Von Wagner, M; et al. (December 2006). "IP-10 predicts viral response and therapeutic outcome in difficult-to-treat patients with HCV genotype 1 infection". Hepatology. 44 (6): 1617–25. doi:10.1002/hep.21407. PMID 17133471.
  • Romero, AI; Lagging, M; Westin, J; Dhillon, AP; Dustin, LB; Pawlotsky, JM; Neumann, AU; Ferrari, C; et al. (October 2006). "Interferon (IFN)-gamma-inducible protein-10: association with histological results, viral kinetics, and outcome during treatment with pegylated IFN-alpha 2a and ribavirin for chronic hepatitis C virus infection". The Journal of Infectious Diseases. 194 (7): 895–903. doi:10.1086/507307. PMID 16960776.

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