Efavirenz still more effective than indinavir after 72 weeks

Keith Alcorn
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This article is more than 24 years old.

The non-nucleoside efavirenz continues to show better anti-viral effects after 72 weeks than the protease inhibitor indinavir, according to data released at the ICAAC conference in San Francisco yesterday.

The Du Pont 006 study compared efavirenz or indinavir in combination with AZT/3TC versus efavirenz and indinavir. After 72 weeks follow-up, 60% of those originally assigned to AZT/3TC/efvairenz still had viral load below 50 copies, compared to 40% of those randomised to receive AZT/3TC/indinavir, and 46% of those who received EFV/IDV. This analysis included those who stopped their original combination for any reason, including viral load rebound.

The research group, led by Dr Schlomo Staszewski of Frankfurt University, also reported on the relative speed with which individuals on the different combinations experienced treatment failure due to viral load rebound or side effects. Those in the indinavir-containing arms were significantly more likely to have experienced viral load rebound, discontinued their original treatment or developed AIDS-related illnesses after 72 weeks, and this trend persisted in those who had been taking the trial drugs for longer. 41% of those receiving AZT/3TC/indinavir had discontinued their original treatment by 72 weeks; just under half due to side effects (17%), compared with 24% of the AZT/3TC/efavirenz group. In this group approximately a third (7%) of discontinuations were due to side effects, with neuropsychiatric side effects accounting for approximately one in seven (1.1%).

Glossary

nucleoside

A precursor to a building block of DNA or RNA. Nucleosides must be chemically changed into nucleotides before they can be used to make DNA or RNA. 

lymph nodes

Bean-sized structures throughout the body's lymphatic system, where immune cells congregate to fight infections. Clusters of lymph nodes are found in the underarms, the groin, and the neck.

trend

In everyday language, a general movement upwards or downwards (e.g. every year there are more HIV infections). When discussing statistics, a trend often describes an apparent difference between results that is not statistically significant. 

replication

The process of viral multiplication or reproduction. Viruses cannot replicate without the machinery and metabolism of cells (human cells, in the case of HIV), which is why viruses infect cells.

reservoir

The ‘HIV reservoir’ is a group of cells that are infected with HIV but have not produced new HIV (latent stage of infection) for many months or years. Latent HIV reservoirs are established during the earliest stage of HIV infection. Although antiretroviral therapy can reduce the level of HIV in the blood to an undetectable level, latent reservoirs of HIV continue to survive (a phenomenon called residual inflammation). Latently infected cells may be reawakened to begin actively reproducing HIV virions if antiretroviral therapy is stopped. 

Delegates at the conference are eagerly awaiting the results of another study which will report on the relative activity of efavirenz and protease inhibitor-containing regimens in lymph nodes, the main reservoir of HIV replication in the body. Previous studies have found that protease inhibitor treatment is associated with much greater viral clearance from lymph node tissue when compared with nucleoside anlaogue treatment, but no evidence has yet been presented to show the impact of non-nucleoside reverse transciptase inhibitors like efavirenz on the lymph nodes.

References

Staszewski S et al. Longer time to treatment failure and durability of response with efavirenz +ZDV + 3TC: first analysis of full 1266 patient cohort from study 006. 39th ICAAC, San Francisco, abstract 507, 1999

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