804 
Body Composition Changes in ART-naive Subjects Treated with Atazanavir or Atazanavir/Ritonavir-based Once-daily HAART: 48-Week Computed Tomography and DEXA Data
Donnie McGrath*1, D Frederick1, V Wirtz1, R Yang1, A Thiry1, M Mathew1, and M Noor2
1Pharma Res Inst, Bristol-Myers Squibb, Wallingford, CT, US and 2Pharma Res Inst, Bristol-Myers Squibb, Princeton, NJ, US
Background: Prospective studies have shown that body fat
changes in ART-naive patients treated with atazanavir (ATV) -based HAART are
similar to an efavirenz (EFV) -based regimen at 48 weeks. However, the effect
of the addition of ritonavir (RTV) to ATV on body composition is unknown.
Methods: This was a randomized trial in ART-naive HIV+
subjects (n = 200) who initiated ATV
400 mg or ATV/RTV 300/100 mg once daily, each with extended-release stavudine
(d4T) and lamivudine (3TC) once daily. Body composition was assessed by
computed tomography and DEXA imaging; in addition, lipodystrophy case
definition scores were recorded using the validated FRAM questionnaire
(subject/investigator reports). These parameters, plus body mass index and
hip/waist measurements, were assessed at baseline, week 24 and week 48 (plus
week 12 for the FRAM questionnaire). Comparisons of computed tomography and
DEXA parameters used t-tests.
Results: Subjects on each regimen had comparable mean
weight changes at 48 weeks from baseline (ATV 5%; ATV/RTV 6% ). Body mass index and waist circumference changes were
comparable between regimens. There were minimal changes in waist‑to‑hip
ratio. There were no statistically significant differences between regimens for
body composition parameters. Loss of arm fat was reported at week 48 by 8% and
6% of the ATV and ATV/RTV subjects, respectively. Investigator-reported lipoatrophy
rates at baseline and at week 48 were 10% and 4% on ATV and 6% and 5% on
ATV/RTV; the rates for lipohypertrophy were 8% and 13% on ATV, and 5% and 11%
on ATV/RTV.
Conclusions: There were no clinically significant
differences in body composition between ATV and ATV/RTV in these d4T-containing
regimens at 48 weeks based on computed tomography and DEXA imaging, and a
validated questionnaire. The increases
in trunk fat, visceral adipose tissue, and
subcutaneous adipose tissue with both regimens are consistent with immune
reconstitution and the return to health seen in the first year of HAART. The
addition of RTV to ATV does not appear to be associated with clinically
significant changes in body composition at 48 weeks.
|
Body Composition Changes through 48
Weeks
|
|
|
ATV
400
|
ATV
300/RTV 100
|
|
|
Baseline
|
48
weeks
|
%Δ
|
Baseline
|
48
weeks
|
%Δ
|
|
DEXA
(n)
|
104
|
89
|
89
|
93
|
72
|
72
|
|
Trunk
fat (kg) ±SE
|
9.1±0.59
|
10.2±0.56
|
15%**
|
8.9±0.59
|
9.2±0.57
|
12%*
|
|
Limb fat (kg) ±SE
|
7.6±0.58
|
7.6±0.58
|
–3%
|
7.7±0.53
|
7.5±0.57
|
2%
|
|
Computed tomography (n)
|
99
|
85
|
83
|
84
|
68
|
65
|
|
Visceral adipose tissue (cm2) ±SE
|
85.4±4.8
|
116.4± 6.58
|
34%***
|
82.7±5.24
|
105.6±7.91
|
27%***
|
|
Subcutaneous adipose tissue (cm2)
±SE
|
200.6±14.88
|
218.4±15.41
|
11%*
|
187.8±13.98
|
197.3±15.56
|
13%*
|
|
*
Percent changes are computed on the log scale
p
<0.05(*), p <0.001 (**), p < 0.0001(**)
|
|
