2nd HIV patient achieves remission, signaling possible path to a cure

An HIV patient has experienced remission for the second time in documented history, according to a study published this week in the journal Nature.

Why it matters: The patient, a U.K. man who has chosen to remain anonymous, has only been in remission for 18 months, so researchers are hesitant to call this a “cure.” But it’s nonetheless the first time that researchers have been able to duplicate the results of the so-called “Berlin patient” — which is the only other documented case of a permanent remission from the virus that causes AIDS, and is widely thought to have been an anomaly.

What they did: Like the Berlin patient, the new case involves an HIV positive patient who was treated with a stem cell transplant intended to target cancer, not the HIV. However, the stem cell transplants in both cases came from donors with a protein mutation known as CCR5. H.I.V. uses the protein to enter immune cells, but is unable to attach to the mutated version.

Yes, but: Larger scale stem cell transplants to combat HIV would be too impractical and risky to present a viable path to a cure. However, some researchers are examining whether gene-therapy techniques to induce the CCR5 mutation on immune or predecessor stem cells could be an option. There are considerable risks here too, namely that other genes could be altered in detrimental ways.

But, but, but: The CCR5 mutation would not successfully defend against strains of the HIV virus that use a different protein, known as CCR4, to enter immune cells.

Our thought bubble, via Axios Science Editor Andrew Freedman: A sample size of one — achieved in Berlin over a decade ago — is now a sample size of two. It’s therefore difficult to assess the treatment's effectiveness, potential complications, odds of success and other factors, but it’s still an extraordinary and hopeful sign. The concept of a cure is now slightly more real, albeit with an abundance of caution.