Switching from lopinavir-ritonavir to raltegravir

Antiretroviral treatment based on lopinavir-ritonavir is effective but may cause lipid abnormalities and other undesirable effects, and a switch to another regimen might be considered. Raltegravir is a new drug that acts as an HIV-1 integrase strand transfer inhibitor. A switch from lopinavir-ritonavir to raltegravir-based treatment has been assessed in two international trials reported together.

In two multicentre trials carried out at 81 centres on five continents, a total of 702 adult patients taking a lopinavirritonavir-based regimen were randomized to continue the same treatment or to switch to raltegravir. All patients had had undetectable viral RNA levels for at least 3 months on lopinavir ritonavir and continued to take at least two nucleoside or nucleotide reverse transcriptase inhibitors. In the first 12 weeks lipid concentrations fell in the switch group and rose in the continuation group. The changes were: (switch vs continue) total cholesterol –12.6% vs +1.0%, non-HDL cholesterol –15.0% vs +2.6%, triglycerides –42.2% vs +6.2%. Viral RNA concentration at week 24 was <50 copies per mL in 90.6% of the continuation group and 84.4% of the switch group. Adverse event frequencies were similar in the two groups. The trials were stopped at 24 weeks because of lower virological efficacy in the raltegravir group.

Switching to raltegravir improved lipid profiles but was associated with deterioration in viral efficacy.

Eron JJ et al. Switch to a raltegravir-based regimen versus continuation of a lopinavir-ritonavir-based regimen in stable HIV-infected patients with suppressed viraemia (SWITCHMRK 1 and 2): two multicentre, double-blind, randomized controlled trials. Lancet 2010; 374: 396–407; Kilby JM. Switching HIV therapies: competing host and viral factors. Ibid: 352–354 (comment).