Four year results from a five year, double-blind, randomised, non-inferiority study comparing raltegravir to efavirenz (each with tenofovir plus FTC) in treatment-naïve patients were presented by Jurgen Rockstroh.
The study design, matched baseline characteristics and safety and efficacy results from earlier analyses have already been presented at earlier meetings. The new subgroup analyses (including baseline CD43, viral load >100,000 copies/mL, hepatitis and demographic responses) focused on virological efficacy with discontinuations related to viral failure included but discontinuations for other reasons excluded and using an observed failure approach.
From approximately 280 patients in each arm at baseline, 223 (79%) and 197 (70%) completed the 192 week analysis, in the raltegravir and efavirenz arms respectively. Discontinuations were all less frequent in the raltegravir arm: virological failure (n=5 vs 8); side effects (n=13 vs 26); and loss to follow-up (n=8 vs 17)
At 192 weeks, the primary analysis of viral suppression to
CD4 increases were + 60 cells/mm3 higher in the raltegravir arm (95%CI 24, 95).
Overall clinical events (96% vs 98%, p = 0.16), discontinuations due to drug-related events (5% vs 8%, p = 0.173) and serious adverse events (18% in each arm, p = 0.91) were similar between the two study groups, raltegravir was associated with significantly fewer drug-related events (50% vs 80%, p < 0.001).
There were no statistically significant differences in response between groups by gender, age, race/ethnicity, viral load >100,000 c/mL, CD4 > 200 cells/mm3, hepatitis coinfection or HIV sub-type. Raltegravir showed a significantly stronger virological response in the3 is complicated by a trend to favour efairenz when CD4 counts were3.
These results support durability and safety of raltegravir. they also show that after week 192 raltegravir achieves superiority compared to efavirenz with the difference largely driven by efavirenz-related side effects.
The CD4 difference may also be important for patients with sub-optimal CD4 responses on other HAART combinations.
Rockstroh JK et al. Long-term efficacy of raltegravir or efavirenz combined with TDF/FTC in treatment-naïve HIV-1-infected patients: week-192 subgroup analyses from STARTMRK. 13th EACS, 12–15 October 2011, Belgrade. Abstract PS 1/1.