Starting
antiretroviral therapy (ART) has significant benefits and entails few risks for
individuals with a low pre-treatment viral load, according to analysis of results
from a large treatment initiation study published in the Journal of Acquired Immune Deficiency
Syndromes
. Prompt initiation of ART was associated with robust increases in
CD4 cell count, sustained viral suppression and favourable changes in
inflammatory biomarkers. The investigators also calculated that treatment would have public health benefits by almost eliminating the risk of
onward HIV transmission.

The study involved
patients with a baseline viral load below 3000 copies/ml recruited to the START
(Strategic Timing of Antiretroviral Treatment) study. This unequivocally established
the benefits of ART for patients with higher CD4 cell counts (above 500
cells/mm3). Treatment guidelines around the world now recommend ART
for all individuals, regardless of CD4 cell count.

However, a small
number of individuals with HIV have a persistently low viral load even without the
use of ART, leading some to question whether ART is necessary. Investigators from
the START study examined their data to see if these patients benefit
from therapy.

A total of 4684
adult HIV-positive patients were recruited to the study. All had a CD4 cell
count above 500 cells/mm3 and were randomised to start immediate ART
or to defer therapy until their CD4 cell count fell below this level.

The current
analysis was restricted to the 1134 individuals (25% of the total study
population) who had a pre-treatment viral load below 3000 copies/ml.

The investigators
compared clinical outcomes (serious non-HIV-related illnesses, hospitalisations
and all-cause mortality), viral load, CD4 cell count and biomarkers (including
those indicating inflammation) between the immediate and deferred ART groups.

The median
baseline CD4 cell count was 714 cells/mm3, average age was 37 years
and the majority of participants (60%) were male. A small sub-set of patients
(n = 93) had a pre-treatment viral load below 50 copies/ml.

Participants were
almost equally randomised to immediate (n = 555) or deferred therapy (n = 579).

A serious clinical
outcome was observed in 64 patients in the immediate and 61 patients in the
deferred group, a non-significant difference.

Immediate therapy
had clear benefits in terms of viral suppression. After twelve months of
follow-up, 93% of patients in the immediate compared to 22% of those in the
deferred group had a viral load below 200 copies/ml. There was evidence that
viral load suppression below 50 copies/ml would not be maintained without ART. During
the first year of follow-up, 55% of individuals in the deferred group with a
baseline viral load below 50 copies/ml experienced an increase in viraemia
above this level.

CD4 cell counts
increased among the patients who started immediate ART but declined among the
patients deferring treatment. After twelve months of follow-up, mean CD4 cell
count was 125 cells/mm3 higher in the immediate ART group and by
month 36 this had increased to a mean difference was 235 cells/mm3. Nonetheless, regardless of study arm, CD4 cell count remained stable in the sub-group of
patients with a baseline viral load below 50 copies/ml.

There was little
difference over three years of follow-up between the immediate and deferred
groups in the proportion experiencing serious changes in haemoglobin, platelet
count, creatinine,  ALT and kidney
function.

However, there
were beneficial changes in several biomarkers indicating systemic inflammation
in the immediate study arm, but not among patients who deferred treatment. In the sub-group with a baseline viral load below 50 copies/ml, these differences were not significant.

Finally, immediate
treatment was calculated to have significant public health benefits. The
investigators estimated that over twelve months the rate of onward HIV
transmission would be 0.2 per 100 patients in the immediate group but 3.2 per
100 patients in the deferred group.

Even with just 93 individuals with a pre-treatment viral load below 50 copies/ml included, Dr Irini Sereti and colleagues say that this is the largest randomised study of such individuals to date. For this group, a clear clinical benefit to starting ART was not observed, but neither was there evidence of harm. As clinical trials do not provide clear guidance on how to treat individuals with such rare disease phenotypes, they recommend that clinical decision making should be individualised and based on a partnership with the patient.

“In conclusion,”
write the authors, “for most HIV-positive people with HIV RNA below 3000
copies/ml, although there are low numbers of clinical events, our analyses show
that immediate ART results in suppressed HIV RNA, CD4 cell count increases,
little evidence of increased serious clinical outcomes, and an estimated modest
decrease in onward HIV transmission.”