The effect of BMI on efficacy, safety and tolerability of lopinavir/r in women
Polly Clayden, HIV i-Base
Body mass index (BMI) can lead to alterations in pharmacokinetics and pharmacodynamics. Data describing the relationship between BMI and clinical outcomes of ART in women are limited.
Investigators from Abbott conducted a meta-analysis in women taking lopinavir/ritonavir (LPV/r)-based regimens in order to look at the effect of BMI on efficacy, safety, and tolerability. Ashwaq Hermes presented findings from this study.
All prospective randomised controlled trials (RCTs) in the company database in adults receiving LPV/r in regimens with two NRTIs, having BMI data, and baseline to week 48 efficacy, safety, and tolerability data were included.
Women were stratified by baseline BMI (kg/m2) into <18.5, ≥18.5-< 25, ≥25-<30 and ≥30 groups. As the number of women with BMI <18.5 was low (n=28), the investigators selected categories of <25 (normal), ≥25-<30 (overweight) and ≥30 (obese) for the analyses.
The meta-analysis included 485 women from seven RCTs, 258 with normal BMI, 130 were overweight women, and 97 categorised as obese. There were statistically significant differences (p<0.05) among the normal, overweight, and obese groups in baseline demographic characteristics: percentage of white women, 53.9%, 36.9% and 25.8% respectively; percentage of Latina women, 17.4%, 33.8%, and 20.6%, respectively and rate of hepatitis C co-infection, 17.2%, 10.8%, 6.2%, respectively.
There were also statistically significant differences in the three groups in baseline disease characteristics: mean viral load, 4.6, 4.4, and 4.3 log10 copies/mL, respectively, and mean CD4 counts 214, 244, and 278 cells/mm3, respectively.
Efficacy was similar across the groups at week 48. Similar proportions of women had viral load <50 copies/mL, 65.1%, 57.7% and 57.7%, respectively (ITT analysis). Mean increases in CD4 counts were also similar across the normal, overweight, and obese groups, 197, 158, and 172 cells/mm3, respectively.
Incidence of grade 3 and above adverse events (AEs) was also similar across the groups, 29.5%, 29.2%, and 41.2%, respectively, p=0.087. Differences were seen in the incidence of moderate/severe abdominal pain, 0.8%, 0%, 7.2%, respectively and diarrhea 9.3%, 10.8%, and 22.7%, respectively in the normal, overweight and obese groups, both p<0.05. These AEs were significantly higher, p<0.05, in the obese women compared with the other two groups. There was no significant difference in the incidence of nausea and vomiting among the three groups.
The investigators noted that increasing BMI is associated with a greater prevalence of diarrhea and abdominal pain, but not nausea or vomiting, in the general population. Also dietary differences among the BMI groups could be confounding, and this information was not collected or controlled for in the meta-analysis. Furthermore people with high BMI have elevated incidence of non-alcoholic fatty liver disease, which is associated with liver fibrosis and changes in drug metabolism.
They concluded that direct comparisons of dose safety and efficacy by BMI groups are needed to increase the understanding of obesity related changes and the impact on treatment.
As reported in other studies, increased weight did not lead to higher rates of virological failure, suggesting that pharmockinetics for lopinavir do not have a direct association with higher weight, even though the PK data were not available or analysed.
However, although the results were not significantly different, it is unclear whether a formal test of equivalence was performed. There is >7% difference between the normal group and the other two groups and response rates appear lower in heavier groups. It would be interesting to see the confidence intervals for the differences which would have to be to conclude equivalence. The CD4 count increases also seem to be lower.
It would also have been interesting to see whether lopinavir/ritonavir has an impact on BMI in relation to baseline BMI.
Hermes A et al. A meta-analysis of the effect of BMI on efficacy, safety, and tolerability of lopinavir/ritonavir in HIV-infected women in randomised clinical trials. 2nd International Workshop on HIV and Women. 9-10 January 2012, Bethesda, MD. Oral abstract O_15.