Results Baseline patient characteristics A total of 1368 patients were randomized and treated. Gender data were available for all patients and race data for 1352 patients. The majority of patients were male and White. There were 26 patients whose race was other than those presented. The proportions of female patients were higher in Africa and Asia than in the USA, Canada, ABT-751 E7010 Europe and Australia and Latin America. For the overall population, median baseline viral load was 5.0 log10 copies/mL and median CD4 cell count was 256 cells/mL. Baseline disease characteristics were generally similar between the subgroups. Effect of gender and race on efficacy within treatment groups High response rates were observed at week 48 and were similar for men and women for both the RPV and EFV treatment groups.
In line with the results for the overall population, there was a higher virologicaland race subgroup Roscovitine CDK inhibitor were similar between RPV and EFV. In line with the results for the overall population, virological failure rates were higher in the RPV than EFV subgroups. However, men and women in the RPV groups had very similar rates of virological failure, in contrast, women had a lower rate of virological failure than men in the EFV groups. Discontinuations because of AEs/deaths and for other reasons were proportionally higher for EFV than for RPV for both genders, and therefore overall there were no observed gender related differences in the proportion of responders. Where gender differences in response rate to ARV regimens have been observed, in most cases the cause has not been an inherent difference in antiviral activity of ARVs in men and women.
In the CASTLE study, the lower response rate in women compared with men was driven by discontinuations for reasons other Epothilone A than virological failure, and no difference in response rate was observed in the on treatment analysis. Similarly, a small, albeit nonsignificant, difference in response rate between women and men in the gender, race, and clinical experience, study of darunavir/ritonavir was attributable to a higher discontinuation rate in women. Reasons for the higher discontinuation rate appear complex but have included poorer adherence, pregnancy, and a higher incidence of some gastrointestinal AEs in women than in men. In contrast, discontinuation rates in ECHO and THRIVE were similar for men and women, this was particularly apparent in the RPV groups.
The difference in response rates according to race, which was observed in both the RPV and EFV treatment groups, is consistent with the findings of several trials with other ARVs which also observed lower response rates in Black, compared with Asian and White, patients. In this study, the lower responses in Black patients were mainly a result of a higher frequency of virological failure and treatment discontinuation for reasons such as loss to follow up, noncompliance and withdrawal of consent, compared with Asian and White patients. Of note, in both treatment groups, the proportion of Black patients who reported adherence was lower than for the other racial groups, which could explain the higher virological failure rate in Black patients. In other studies, a relationship has been observed between adherence and a lower virological response to ARV regimens