In a large, international study of HIV-1–serodiscordant couples, the receipt of antiretroviral therapy by the infected partner decreased transmission to the uninfected partner as well as rates of clinical events in the HIV-1–infected partner.
Because the sexual transmission of HIV-1 from infected persons to their partners is strongly correlated with concentrations of HIV-1 in blood and in the genital tract, it has been hypothesized that antiretroviral therapy could reduce sexual transmission of the virus. In this study HIV-1 serodiscordant couples were randomly assigned in a 1:1 ratio to either an early or delayed strategy for receipt of antiretroviral therapy.
• Did early treatment prevent transmission of HIV-1 to sexual partners of infected patients?
Through viral genetic analysis, 28 transmissions were linked to the HIV-1-infected participant and his or her sexual partner, with 1 transmission in the early-therapy group and 27 transmissions in the delayed-therapy group for a hazard ratio in the early-therapy group of 0.04 (95% CI, 0.01 to 0.27; P<0.001).
• What factors were present in the transmissions of HIV-1 that occurred in this study?
A high viral load in blood plasma of infected participants at baseline increased the risk of HIV-1 transmission. Conversely, self-reported 100% condom use at baseline was associated with a reduced risk of HIV-1 transmission.
Morning Report Questions
Q: Did the early therapy group have fewer clinical events than the delayed therapy group?
A: A total of 105 treatment end points, as measured by the first serious HIV-1-related clinical event or death, were observed in HIV-1-infected participants: 40 in the early-therapy group and 65 in the delayed-therapy group (hazard ratio, 0.59; 95% CI, 0.40 to 0.88; P=0.01). The difference in the rate of clinical events was driven mainly by the incidence of extrapulmonary tuberculosis.
Q: What adverse events were most frequently associated with early antiretroviral therapy in this study?
A: Grade 3 or 4 laboratory abnormalities during study follow-up occurred in 242 participants (27%) in the early-therapy group and 161 participants (18%) in the delayed-therapy group (P<0.001). The most frequent laboratory abnormalities included neutropenia, abnormal phosphate level, and total bilirubin elevations.