BOSTON – For infants with HIV infection, baseline immune function and birth health appear to influence viral control after the discontinuation of antiretroviral therapy (ART), an analysis of data from the landmark CHER trial shows.

Among 183 children diagnosed with HIV between 6 and 12 weeks of age who were started on early, time-limited ART, longer time to viral rebound after treatment discontinuation was associated with higher baseline CD4 percentages, higher birth weight, and with achievement of viral suppression within 40 weeks of starting on ART, reported Man Chan, PhD, of the Medical Research Council clinical trials unit at University College London.

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“On the other hand, we did not find an association between age at ART start and length of therapy with a longer time to rebound. However, we should interpret these results with some caution, obviously because the range of ages at ART start was quite small, from 6-12 weeks, so we didn’t really have enough spread in the data to enable us to draw solid conclusions,” she said at the annual Conference on Retroviruses & Opportunistic Infections.

The CHER trial compared South African infants with HIV on either 40 or 96 weeks of immediate ART with those on deferred ART. The results showed that early time-limited ART was associated with better clinical and immunologic outcomes than was deferred ART and influenced a change in treatment guidelines (Lancet 2013 Nov 9;382[9904]:1555-63).

In the current analysis, investigators examined viral control after treatment interruption in early-treated children and looked for factors that could influence time to viral rebound after ART cessation.

They measured viral load from stored samples at 1.8 weeks after ART interruption and then every 12 weeks thereafter. They defined viral rebound as two consecutive samples with 400 or more copies/mL.

Of the 183 children in the sample, 177 had a rebound; the remaining six children were censored from the analysis, five because they had restarted ART, and one child who remained in viral suppression with an undetectable viral load and was asymptomatic for 8.5 years off ART.

The estimated cumulative probability of rebound was 70% at 2 months following ART interruption, 80% at 4 months, 94% at 6 months, and 99% at 8 months.

In multivariable analysis, factors significantly associated with longer time to viral rebound included higher baseline CD4 counts (P = .03), higher birth weight (P = .032), and viral suppression within 40 weeks of starting on ART (P = .028)

In contrast, there were no significant associations with other factors in the multivariate model, including sex, baseline viral load, baseline CD8 percentage, HIV stage, status of therapy to prevent mother-to-child transmission, age at ART initiation, length of therapy, or treatment center.

Sensitivity analyses of a few cases in which there was a 4-7 month gap between rebound and the last viral load below 400 copies/mL before rebound showed similar results, Dr. Chan noted.

The study was the U.S. National Institutes of Health. Dr. Chan reported having nothing to disclose.

SOURCE: Violari A et al. CROI 2018, Abstract 137

Time to HIV rebound in infants off ART linked to birth health