A small group of patients with HIV in France have been able to stop taking Aids drugs without any resurgence of the virus in their bodies, giving scientists new hope that a "functional cure" for HIV may be possible.

The Visconti cohort, as the 14 French patients are being called, were all given antiretroviral drugs to control the virus soon after becoming infected with HIV, which is not very common. They remained on medication for at least three years, but then stopped.

Usually, the levels of virus in the body will rise without drug suppression and cause the patient to become ill and eventually develop Aids. But the Visconti cohort has remained well, with extremely low levels of virus in their system, for a median of seven years.

"We believe that this is a really promising group of patients," said Asier Saez Ciron from the Institut Pasteur in France, one of the scientists involved in the research which was presented at the International Aids Conference in Washington.

The existence of people who do not become ill even though they are infected with HIV – the so-called "HIV controllers" – is already known. The excitement felt by scientists over the Visconti cohort is because it appears that medical intervention has brought about similar results.

"This is a promise that the functional cure could be achieved," said Saez Ciron.

The work is further evidence that people should be given drugs as soon as possible.

"These results suggest that the antiretroviral treatment should be started very early after infection," said Charline Bacchus, lead researcher on the study at the French National Agency for Research on Aids and Viral Hepatitis (ANRS).

The study is one of three pieces of work presented at the conference this week that have boosted hopes not of a total cure for HIV, but of what is being called a functional cure, because the virus remains in the body at very low levels but does not cause disease and the patient is able to stop taking medication.

A campaign by scientists to find a cure for Aids has been gathering momentum over the last two years, culminating in a blueprint published just ahead of the conference in Washington. Francoise Barré Sinoussi, Nobel prize laureate for identifying the human immunodeficiency virus (HIV) in the 1980s, is leading the drive, which she says must go hand in hand with efforts to find a vaccine.

Timothy Ray Brown, the so-called Berlin Patient, has been the proof of concept. Brown, who is an American living in the city, had HIV and leukaemia.

When he underwent a stem cell transplant for his cancer, his doctor found a donor who had genetic resistance to HIV. Brown's cancer and his HIV were cured. However, he had serious complications from the treatment, which would be unrealistic and unaffordable for most people.

The conference also heard, however, of two more stem cell transplants that appear to have resulted in functional cures. The two men with HIV had lymphoma, a cancer of the lymphatic system.

They underwent stem cell transplantation for the cancer, but this time not involving donors with genetic resistance to HIV. They received mild chemotherapy which allowed them to stay on their antiretroviral medication throughout.

Although HIV was detectable in heir cells immediately after the transplant, over time the uninfected donated cells replaced the infected cells. Both patients appear to be HIV-free, one of them two years and the other three and a half years after their operation.

A third study by David Margolis and colleagues at the University of Carolina, published in Nature, appears to show that it is possible to reach the low levels of virus that "hide" in cells and have never been susceptible to treatment, using a dose of a drug that inhibits an enzyme involved in "silencing" HIV.

© Guardian News and Media 2012