The risk of developing extensive drug resistance is low 10 years after starting antiretroviral therapy, according to researchers involved with a United Kingdom study published December 8 in The Lancet and reported by AIDSmap. Even after HIV becomes resistant to meds in three of the major classes of drugs, the authors add, the chances of survival are still good.

Andrew Phillips, PhD, from the Department of Primary Care and Population Sciences at the Royal Free and University College Medical School in London, and his U.K. Collaborative HIV Cohort (CHIC) colleagues examined the medical records of 7,916 HIV-positive people starting therapy for the first time.

At the time of their analysis, 167 people—2.1 percent of the cohort—had extensive triple-class drug failure. People were highly treatment-experienced by the time triple-class drug failure was documented, 90 percent having used at least seven antiretroviral drugs and 19 percent having used at least nine. People who started treatment with a CD4 count below 200 were more than twice as likely to develop triple-class drug failure over10 years than people who started treatment with a CD4 count above 200.

Researchers determined that the risk of developing triple-class failure five years after starting treatment was relatively low, occurring in approximately 3.5 percent of patients.  The estimated risk 10 years after starting HIV treatment was still low—approximately 10.2 percent of patients were at risk for triple-class drug resistance. What’s more, the risk of death remained low among patients who developed triple-class-resistant HIV, on the order of 10.6 percent after five years.

While Phillips’s team concluded that this is fairly hopeful news for developing countries where triple-class regimens are just being rolled out, they also pointed out that developing countries will be challenged to treat those who do develop multi-class drug failure as second-generation antiretrovirals may not be available there for some time to come.