Background:  In resource-limited settings, HIV infection among women is often identified through voluntary counseling and testing followed by treatment with short-course zidovudine (AZT) or single-dose nevirapine (sdNVP) to prevent mother-to-child transmission (PMTCT). In scaling-up ART, in Africa, treatment with low-cost, generic dual nucleoside plus non-nucleoside reverse transcriptase inhibitors are recommended. However, there is growing concern about the effect of PMTCT ART exposure on responses to HAART regimens.

Methods:  At CIPLA, Mumbai, India, 257 HIV⁺ postpartum women and their spouses (53 women and 33 men) with <200 CD4 cells received ART with zidovudine (AZT) + lamivudine (3TC) twice daily and nevirapine (NVP) twice daily.. CD4 counts were evaluated using pan-leukogating, dual platform FACS, and HIV-1 RNA quantified by ultrasensitive Roche Amplicor (1.5). Virologic responses were compared between men and women by Fischer’s exact test and Mann-Whitney U tests for continuous variables.

Results:  Of the total, 86 (53 women and 33 men) completed 24 weeks, and 69 (41 women and 28 men) completed 48 weeks of therapy. Women were significantly younger than men, mean of 31.6±4.5 vs 36.8±5.9 years, respectively, p <0.001. Median CD4 (25^th to 75^th IQR) counts for women and men at baseline were similar; 128.5 (72 to 177) and 119.0 (70 to 160) cells/μL, respectively; and geometric mean RNA, log₁₀ 4.9 copies/mL. At 48 weeks, mean CD4 counts for women and men increased to 270 (195 to 335) and 226 (177 to 300) cells/μL, respectively. Men demonstrated a significantly better virologic response at 48 weeks:  <500 and <50 copies/mL of HIV RNA were achieved in 26 (93%) and 22 of 28 (79%) men vs 29 (71%) and 22 of 41 (53%) women, p <0.025. No difference was seen in 48-week virologic suppression among 27 women who received AZT vs 14 women who received sdNVP:  19 of 27 (70%) vs 10 of 14 (71%) <500 copies and 13 of 27 (56%) vs 7 of 14 (50%) <50 copies. All subjects demonstrated >95% adherence by monthly questionnaires and pill counts.

Conclusions:  AZT+3TC+NVP treatment of subtype C HIV-1 in Zimbabwe was clinically successful, however, men had a significantly better virologic response, than women at 24 and 48 weeks. This may be explained by sdNVP and shsort-course AZT for PMTCT, but there was no apparent difference among women exposed to 1 or the other intervention. Community-based monitoring, toxicity managemen, and adherence counseling will allow evaluation of PMTCT regimens and response to ART.