The latest hopes of curing Aids were dashed yesterday when US researchers said HIV returned in two men who briefly eradicated the virus after bone marrow transplants for cancer.
Only one person, American Timothy Brown, is believed to have been cured of HIV. He suffered from leukaemia, received a bone marrow transplant from a rare donor who was resistant to HIV, and has shown no sign of the virus for six years.
"The return of detectable levels of HIV in our patients is disappointing, but scientifically significant," said Timothy Heinrich, a physician-researcher at Brigham and Women's Hospital in Boston. "Through this research we have discovered the HIV reservoir is deeper and more persistent than previously known," he said.
Both HIV-positive men received bone marrow transplants as treatment for Hodgkin's lymphoma, one in 2008 and the other in 2010. About eight months after their operations, HIV was no longer detectable. The patients stayed on antiretroviral therapy and eventually decided to cease taking the drugs this year.
In July doctors announced early, encouraging results: one patient appeared to still be HIV-free after being off the drugs for seven weeks and the other for 15 weeks. But signs of HIV were found in the first patient 12 weeks after stopping therapy, and in the second patient after 32 weeks.
"Both patients have resumed therapy and are currently doing well," Heinrich said.