Efficacy of lopinavir/r in patients with advanced HIV (CD4 <25 cells/mm3)
Simon Collins, HIV i-Base
An analysis from four randomised studies of lopinavir/r, that stratified patients by baseline CD4, showed that comparable results were achieved by patients even with the most advanced HIV defined as CD4 counts <25 cells/mm3 and/or viral load >300,000 copies/mL (comprising 11% and 21% of the pooled study populations respectively).
No significant differences were seen in the proportion of patients with viral load <50 copies/mL at week 48 by intent-to-treat analysis, when looking at either baseline CD4 or viral load. There were also no significant differences in time to loss of virological response (TLVR).
Using CD4 >500 cells/mm3 as a reference, the hazard ratios (95% CI) for TLVR were 0.7 (0.3-1.4), 0.6 (0.3-1.2), 0.7 (0.3.1.3) 0.8 (0.3-1.9) and 1.0 (0.5-2.1) in patients with baseline CD4 counts of 350-488, 200-348, 50-99, 25-49 and <25 cells/mm3 respectively. In the analysis of baseline viral load, using <30,000 as the reference, HR (95%CI) were 0.9 (0.5-1.6), 1.3 (0.7-2.2) and 0.8 (0.4, 1.6) in patients with baseline levels of 30-100k, 100-300k and >300k respectively.
CD4 responses were generally comparable by baseline group, with 44% and 63% of those with baseline counts <25 and 25-49 cells/mm3 respectively increasing to >200 cells/mm3 at week 48.
King M, Johnson M, Youle M et al. Antiviral activity of lopinavir/ritonavir-based regimens in subjects with CD4 counts below 25 cells/mm3. 10th EACS, Dublin 2005. Poster PE7.3/4.