HCV viral load before therapy associated with post-treatment relapse in HIV/HCV coinfected

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HIV/hepatitis C virus (HCV) coinfected patients who have a high HCV load at the start of treatment for hepatitis C form the group of patients most likely to experience a relapse of their HCV infection, say Spanish researchers writing in the August 1st edition of the Journal of Acquired Immune Deficiency Syndromes.

Response to anti-HCV treatment after a month is also a good predictor of relapse, but longer than standard duration of hepatitis C therapy does not improve the chances of HIV/HCV-coinfected patients clearing the virus, according to data from the Pegasys Ribavirina España Coinfección [correct] (PRESCO) study.

The recommended treatment for HCV is a combination of pegylated interferon plus ribavirin. Individuals who have both HIV and HCV are less likely than HCV-monoinfected patients to respond to anti-HCV treatment - possibly due to the immunologic impairment caused by HIV – and it has been thought that they could benefit from longer treatment courses.

Glossary

relapse

The return of signs and symptoms of a disease after a patient has been free of those signs and symptoms. 

relative risk

Comparing one group with another, expresses differences in the risk of something happening. For example, in comparison with group A, people in group B have a relative risk of 3 of being ill (they are three times as likely to get ill). A relative risk above 1 means the risk is higher in the group of interest; a relative risk below 1 means the risk is lower. 

ribonucleic acid (RNA)

The chemical structure that carries genetic instructions for protein synthesis. Although DNA is the primary genetic material of cells, RNA is the genetic material for some viruses like HIV.

 

pegylated interferon

Pegylated interferon, also known as peginterferon, is a chemically modified form of the standard interferon, sometimes used to treat hepatitis B and C. The difference between interferon and peginterferon is the PEG, which stands for a molecule called polyethylene glycol. The PEG does nothing to fight the virus. But by attaching it to the interferon (which does fight the virus), the interferon will stay in the blood much longer. 

detectable viral load

When viral load is detectable, this indicates that HIV is replicating in the body. If the person is taking HIV treatment but their viral load is detectable, the treatment is not working properly. There may still be a risk of HIV transmission to sexual partners.

The PRESCO study was designed to evaluate short and extended duration of treatment for hepatitis C virus (HCV) infection in 389 coinfected patients.

All patients were treated with peg-IFN at a dose of 180 μg[micrograms] per week plus weight-based ribavirin at a dose of 1000 to 1200mg per day. Patients with HCV genotypes 2 or 3 were either treated for six or twelve months, while those with HCV 1 or 4 were treated for either twelve or 18 months. By the end of treatment 24% of patients had relapsed: 33% of HCV-1 patients, 18% of HCV-2/3 and 21% of HCV-4. But extending the duration of treatment did not reduce the risk of relapse- regardless of HCV genotype according to these findings say the authors.

However they did find two strong predictors of relapse- the first being HCV load at the start of treatment. Having a HCV RNA level of 500,000 IU/ml or above increased the risk of relapse by almost five times (relative risk 4.81, 95% CI 1.52-15.22 p = 0.008). Those that responded quickly were also less likely to relapse in the longer term.

Those patients who still had detectable HCV loads after four weeks of treatment were almost three times as likely to relapse by the end of treatment (relative risk 2.95, 95% CI 1.22-7.09 p = 0.02).

One surprising finding was that HCV/HIV coinfected patients taking potent antiretroviral therapy at the same time as their HCV treatment were more likely to relapse (p = 0.04). The authors say that finding could indirectly reflect patients with more advanced HIV disease who may have lost some of the immune function involved in therapy-induced HCV clearance.

But the possibility of drug interactions between HCV and HIV medications cannot be ruled out, they add, particularly between ribavirin and NRTIs.

References

Núñez M et al. Baseline serum hepatitis C virus (HCV) virus level and response at week 4 are the best predictors of relapse after treatment with pegylated interferon plus ribavirin in HIV/HCV-coinfected patients. J Acquir Immune Defic Syndr 2007 45(4): 439 - 444