The final results of the famed HPTN 052 trial found no transmissions between mixed-HIV-status heterosexual couples when the partner living with the virus was treated with antiretrovirals (ARVs) and had a fully suppressed viral load, MedPage Today reports. In 2011, interim results from the trial found that treating HIV early was associated with a 96 percent reduced risk of transmitting HIV between such couples, compared with delaying treatment. The final results reduced this figure to 93 percent.

Publishing their final results in The New England Journal of Medicine, researchers randomly assigned 1,763 people with HIV who were in a partnership with an HIV-negative, opposite-sex individual to receive immediate or deferred ARV treatment. A total of 886 participants started HIV treatment immediately, with CD4 counts ranging between 350 and 550. The 877 people in the deferred group were set to start treatment after two consecutive CD4 counts dropped below 250 or if they had an AIDS-defining illness.

After the 2011 interim results were released, everyone in the deferred group was offered treatment.

The final results were also presented at the 21st International AIDS Conference in Durban, South Africa (AIDS 2016).

The HIV-positive participants were followed for a cumulative 10,031 years, while the HIV-negative partners were followed for a cumulative 8,509 years.

Seventy-eight of the HIV-negative partners acquired the virus during the study, for an infection rate of 0.9 percent per year. Through genetic analysis, the researchers were able to determine that 46 of those transmissions—three in the early treatment group and 43 in the deferred group—were linked to the study partners; researchers were unable to determine a viral link in the case of the remaining six.

Comparing the HIV rates between the early and the deferred group, the researchers found that treating the virus early was associated with a 93 percent reduction in the risk of transmitting HIV.

The 93 percent figure does not represent the risk reduction associated with having an undetectable viral load. The researchers did not identify any transmissions of the virus within couples when the HIV-positive member had a fully suppressed virus thanks to ARV treatment.

To read the study abstract, click here.

To read the MedPage Today article, click here.