Researchers spotlight two cases of eradicated HIV infection

More evidence points to the promise of wiping out HIV for good, but researchers believe that talk of a cure is premature. Two HIV patients who underwent bone marrow transplants to treat their blood cancers have been off their antiretroviral therapies for weeks without visible signs of the virus.

This is big news for HIV researchers and patients who lack cures for the immune system-killing disease, which is commonly combated with antiviral cocktails that can keep the virus under control for decades. As Reuters reported, the bone marrow transplants used to treat the two HIV patients are extremely expensive. The pricey therapy, which was given to the patients in Boston, seems unlikely to become a widely available treatment option for HIV patients. Yet such cases could shed light on pathways that could lead to cures.

The HIV research community is already familiar with the two patient cases, which were highlighted a year ago after signs of HIV were wiped out after the bone marrow transplants. Last year, however, the patients were HIV-free but still taking their antiviral remedies. Timothy Henrich, a Harvard Medical School research at Brigham and Women's Hospital, gave an update today at an AIDS congress in Kuala Lumpur, reporting that one patient has been off his HIV meds for 7 weeks and other for 15 weeks.

What's more, the two cases have an important difference from the so-called "Berlin patient," Timothy Brown, whose HIV was cleared after bone marrow or stem cell transplants that contained cells with the CCR5-Δ32 mutation. That mutation has been likened to providing anti-HIV armor for the immune system. However, the two "Boston" patients in Henrich's study got transplanted cells without the CCR5 mutation, raising the question of how important that genetic abnormality is in the quest for cures, Forbes' Matthew Herper reported.

"There was a sense that Timothy Brown's immune system had been given an armor coating," says Kevin Robert Frost, chief executive of amfAR: The Foundation for AIDS Research, as quoted by Herper. Frost added that the mutation could give Brown immunity to HIV that the patients in the Boston study lack, supporting ongoing research of different therapies to cure the illness.

Sangamo Biosciences ($SGMO) has bet on clinical development of a gene therapy that exploits the CCR5 mutation to combat HIV. In May the biotech outfit reported preliminary Phase II data and touted that increases CCR5-protected CD4 immune cells correlated with a drop in HIV reservoir and increase in CD4 count, which is a classic measure of immune-system health in HIV patients. Full data from the midstage program are expected by the end of this year.

In the meantime, Gilead ($GILD), Johnson & Johnson ($JNJ) and ViiV Healthcare remain prime time players in providing antiviral drugs that dominate the market for branded HIV treatments. Experts say that the quest to bring viable cures to millions of HIV-infected patients around the world could take many more years and could never materialize.

- check out Herper's article
- and the report from Reuters