MONDAY, Feb. 28 (HealthDay News) -- A new study estimates that
between 10 percent and 15 percent of HIV patients in Europe and the
United States are infected with a form of HIV that already has at
least one drug-resistant mutation.
The researchers found that the risk of treatment failure in
these patients is three times higher than normal, and said their
findings confirm the need for drug resistance testing in new
patients to determine which antiretroviral drugs are most likely to
For the study, 10,056 HIV patients who were beginning
combination antiretroviral therapy (cART) for the first time were
categorized into three resistance categories: 90.5 percent (9,102
patients) had no transmitted drug-resistance (TDR); 4.7 percent
(475 patients) had at least one mutation and were receiving fully
active cART; 4.8 percent (479 patients) had at least one mutation
and were resistant to at least one prescribed drug.
Compared to patients without TDR, those with TDR and resistance
to at least one prescribed drug were more than three times as
likely to experience treatment failure, confirming "the need for at
least three fully active antiretroviral drugs to optimize the
virological response to a first-line regimen," the researchers
But the risk of treatment failure was not significantly
different between patients without TDR and those with TDR taking a
fully active cART regimen containing drugs not compromised by
The researchers also found that treatment failure was higher
among patients with TDR who were taking two nucleotide reverse
transcriptase inhibitors (NRTIs) plus one non-nucleotide reverse
transcriptase inhibitor (NNRTI) and were predicted to be on a fully
active treatment, compared to patients on protease inhibitor-based
regimens whose risk of treatment failure was similar to patients
with no TDR.
"If drug-resistant mutations are detected before treatment initiation, a ritonavir-boosted protease inhibitor can be included in the first treatment regimen, which, because of its higher genetic barrier, could better protect from the risk of virological failure than could NNRTI," Dr. Linda Wittkop, of INSERM, University Bordeaux Segalen in Bordeaux, France, and colleagues wrote.
"These findings confirm present treatment guidelines for HIV, which state that the initial treatment choice should be based on resistance testing in treatment-naive patients," they concluded.
The study is published in the Feb. 28 online edition of
The Lancet Infectious Diseases.
The U.S. National Institute of Allergy and Infectious Diseases
has more about