Reversibility of lipoatrophy in HIV-infected patients 2 years after switching from a thymidine analogue to abacavir: the MITOX Extension Study

OBJECTIVE: To determine if long‐term improvement in HIV lipoatrophy can be attained by substitution of thymidine analogues zidovudine (ZDV) or stavudine (d4T) with abacavir (ABC). DESIGN: Long‐term follow‐up (104 weeks) of a randomized, open‐label study. SETTING: Seventeen ambulatory HIV clinics in Australia and London. SUBJECTS: Patients with HIV lipodystrophy were randomized to switch from a thymidine analogue to ABC, while continuing all other antiretroviral therapy (ABC arm) (n = 42) or continue current therapy (ZDV/d4T arm) (n = 43). INTERVENTION: At week 24, all control patients could switch to ABC. Of the original 111 patients randomized, 85 had long‐term follow‐up data, with 77 having imaging data available at 104 weeks. MAIN OUTCOME MEASURE: The primary endpoint was time‐weighted change in limb fat mass, measured by dual‐energy X‐ray absorptiometry (DEXA). RESULTS: At week 104, the mean increase in limb fat for the ABC and ZDV/d4T group was 1.26 +/‐ 2.02 kg and 0.49 +/‐ 1.38 kg, respectively. The time‐weighted change for limb fat was significantly different between the two arms (0.43 kg; P = 0.008). On‐treatment analysis demonstrated a trend for increased limb fat in patients in the ABC arm. Visceral fat accumulation, buffalo hump, self‐assessed lipodystrophy or the lipodystrophy case definition score (LCDS) did not improve. CONCLUSIONS: In patients with moderate‐to‐severe lipodystrophy, significant improvements in subcutaneous fat continued over 104 weeks after switching from a thymidine analogue to ABC. Nevertheless, the lipodystrophy syndrome was still evident, indicating additional strategies need evaluating.