Over three-quarters of HIV-positive individuals in France’s second city have resistance to at least one nucleoside analogue and a quarter of patients have resistance to at least one drug from each of the three major classes or antiretrovirals, according to a study published in the November 7th edition of AIDS.
Investigators at the two major HIV treatment centres in Marseille analysed the prevalence of resistance mutations in 2248 patients between 1997 and 2002. The patients included in the study represented 55% of the total HIV population in Marseille. It was calculated by the investigators that 80% of patients included in the study were taking anti-HIV therapy.
The study was possible because investigators created a database of over 7,000 HIV genotypes and resistance patterns between 1997 and 2002.
The prevalence of resistance was calculated for each year from 1997, including data on the number of patients with resistance to at least one drug from the three major classes of anti-HIV medication. Information was also recorded on the number of patients with resistance to both an NRTI and protease inhibitor (dual resistance), and on the percentage of individuals who had resistance to at least one NRTI, one protease inhibitor and one NNRTI (triple resistance).
Investigators found that 78.3% of patients had resistance to at least one NRTI, and that 47% of patients were resistant to at least one protease inhibitor. In addition, they established that 38.9% of individuals were resistant to an NNRTI.
In March 2002, the proportion of samples with dual resistance ranged from 25.6% to 45.5%. The rate of triple class resistance was 25%.
Trends in the prevalence of drug resistance reflected trends in the use of antiretroviral drugs.
There was a slight increase in the number of patients with NRTI resistance between 1997 and 1999, with rates then stabilising at approximately 80% until the end of the study period. The number of patients with NNRTI resistance leapt from less than 10% in 1997 to almost 40% in 1999, reaching a peak of over 43% in 2001, before falling back to a little over 40% in 2001.The percentage of patients with resistance to a protease inhibitor increased sharply from 20% in 1997 to 40% in 1998, reaching a peak of almost 50% in 1999 before falling back to approximately 40% in 2002.
In 1997 triple resistance was only observed in 3.6% of patients, this increased sharply to 14.7% in 1998 and again in 1999 to 24%. The maximum prevalence of triple resistance occured in 2000, at just under 25%, before a slight decrease to a little over 25% in 2001 and 2002.
The proportion of patients with no resistance mutations fell from 54% in 1997 to 19.7% in 2002.
The investigators conclude that the high prevalence of resistance revealed by their study shows that new anti-HIV drugs are urgently required. In addition, they state that their study shows a need for “a better understanding and a more rational use of genotypic data [that] could allow significant improvements in the management of HIV infection with the current arsenal of antiretroviral drugs.?
Further information on this website
Prevalence of drug resistant HIV in the UK on the rise - news story
Tamalet C et al. Resistance of HIV-1 to multiple antiretroviral drugs in France: a 6-year survey (1997 2002) based on an analysis of over 7000 genotypes. AIDS 17: 2383 - 2387, 2003.