HIV patients showing signs of multidrug resistance in Africa

Significant numbers of patients whose HIV strains developed resistance to older generation drugs are also resistant to modern drugs, finds a new study led by UCL and funded by Wellcome. The research, co-authored by researchers at the London School of Hygiene and Tropical Medicine and published in The Lancet Infectious Diseases , studied 712 HIV patients across the world whose HIV was not controlled by antiretrovirals. The study found that 16% of people who stopped responding to modern first-line treatments had HIV mutations associated with resistance to an older generation of drugs called thymidine analogues. Among patients with a thymidine analogue mutation, 80% were also resistant to tenofovir, the main drug in most modern HIV treatment and prevention strategies. 'We were very surprised to see that so many people were resistant to both drugs, as we didn't think this was possible,' explains lead author Professor Ravi Gupta (UCL Infection & Immunity), who is also an Honorary Consultant in Infectious Diseases at The Hospital for Tropical Diseases, UCLH NHS Foundation Trust. 'Mutations for thymidine analogue resistance were previously thought to be incompatible with mutations for tenofovir resistance, but we now see that HIV can be resistant to both at once. This emphasises the need to check the genetic profile of patient's virus before prescribing first-line treatments, as they may have already developed resistance to other treatments that they did not mention having taken.' Resistance to a drug typically occurs when a patient doesn't take their medication regularly enough, and for first-line treatments to work patients generally need to take their medication 85-90% of the time.