Metabolic benefits 24 months after replacing a protease inhibitor with abacavir, efavirenz or nevirapine.

OBJECTIVE

To evaluate the 24-month metabolic and morphological benefits obtained from replacing the protease inhibitor (PI) in a regimen with nevirapine, efavirenz or abacavir.

DESIGN AND

METHODS

NEFA was a randomized study designed to compare the efficacy of nevirapine, efavirenz or abacavir as substitutes for PI. A subset of 90 patients [abacavir (n = 29), efavirenz (n = 32), nevirapine (n = 29)] formed the metabolic study. Fasting total cholesterol (TC), high density lipoprotein cholesterol (HDL-c) and triglycerides levels were determined. Glucose homeostasis parameters were also collected. Lipodystrophy was evaluated by clinical examination and morphological measurements.

RESULTS

Treatment simplification led to overall lipid profile improvements. At 24 months, the two non-nucleoside reverse transcriptase inhibitors produced similar lipid benefits: HDL-c levels increased [efavirenz, 15% (P = 0.001); nevirapine, 21% (P < 0.001)] and TC to HDL-c ratios decreased [efavirenz, 14% (P < 0.001); nevirapine, 19% (P < 0.01)], an effect not observed in the abacavir arm. Non-HDL-c levels decreased by 10% in both the abacavir (P = 0.001) and efavirenz (P < 0.05) arms. Significant decreases in the levels of triglycerides occurred for the first year in all treatments; however, at 24 months most of the initial loss had been regained. Patients with baseline moderate or severe lipodystrophy obtained less-pronounced lipid benefits. Several insulin resistance markers showed a trend towards improvement. Conversely, no improvements in morphological abnormalities were observed.

CONCLUSIONS

Replacing PI with efavirenz, nevirapine or abacavir improved the lipid profile, with more marked results in non-lipodystrophic patients. In contrast, this strategy does not seem to be effective for reversing body fat abnormalities.