NRTI-sparing regimen achieves better viral suppression

Michael Carter
Estimated reading time 2 minutes
This article is more than 22 years old.

In a head-to-head comparison a regimen containing two protease inhibitors (PI) and an NNRTI has been shown to be more effective at suppressing HIV and just as tolerable as a dual PI, NNRTI and NRTI regimen.

Investigators from the EASIER study (European and South American Study of Indinavir Efavirenz and Ritonavir) presented 24 week data from a multi-centre, open label randomised trial to the XIV International AIDS Conference in Barcelona. The interim data from the 48 week trial showed that people taking an NRTI sparing regimen were more likely to achieve viral suppression to below either 500 or 50 copies/ml. The side effect profile of the two trial regimens were broadly similar and adherence in both the NRTI sparing and containing arms was equally high.

The trial recruited 74 people over 18 years of age with a CD4 count about 100cells/mm3 and a viral load above 5,000 copies/ml. None of the trial participants had ever taken protease inhibitors, NNRTIs, or d4T, the NRTI included in the trial. The volunteers were randomised to receive either 800 mg of indinavir and 100 mg of ritonavir twice daily plus 600 mg of efavirenz once a day, or 800 mg of indinavir, with 100 mg of ritonavir, and the appropriate weight dependent dose of d4T twice daily, with 600 mg of efavirenz once a day.

Glossary

protease inhibitor (PI)

Family of antiretrovirals which target the protease enzyme. Includes amprenavir, indinavir, lopinavir, ritonavir, saquinavir, nelfinavir, and atazanavir.

open-label

A clinical trial where both the researcher and participants know who is taking the experimental treatment. 

tolerability

Term used to indicate how well a particular drug is tolerated when taken by people at the usual dosage. Good tolerability means that drug side-effects do not cause people to stop using the drug.

virological suppression

Halting of the function or replication of a virus. In HIV, optimal viral suppression is measured as the reduction of viral load (HIV RNA) to undetectable levels and is the goal of antiretroviral therapy.

Three people in each treatment arm withdrew from the trial because of side-effects. Of those remaining, the following interim results were seen. At week 24 everybody in the NRTI-sparing regimen had achieved a viral load below 400 copies/ml and 79% a viral load below 50 copies/ml. In the NRTI-containing arm, 82% achieved a viral load below 500 copies/ml and 58% a viral load below 50 copies/ml.

Drug related side effects were slightly more common in the NRTI-sparing arm of the trial (63% of patients reporting adverse effects against 59% in the NRTI arm).

Adherence rates were comparable, with a little over 99% of the NRTI-sparing arm achieving 100% adherence. In the NRTI arm, 100% adherence was noted.

References

Stek M et al. European and South American Study of indinavir, efavirenz and ritonavir (EASIER). Poster presentation LpPp2208 Fourteenth International AIDS Conference, Barcelona, 11 July 2002.

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