As HIV researchers met in Seattle the day after it was reported in Nature that a second patient appears to have been cured of infection with the virus, excitement and questions hung in the air. In the end, the majority view seemed to favour caution — hope, though real, must be tempered with realism. Several reports analysed what the landmark research means, at the moment.
Does anything change for people living with HIV?
Not immediately. The “London Patient” provides “proof of concept” — a potential path to a cure for HIV. But cure is not around the corner, and infected patients are nowhere near a situation in which they can hope to stop taking their pills soon. There are 35 million HIV-positive people in the world, and bone marrow transplants from donors with the HIV-resistant CCR5-delta 32 mutation — which both “Berlin Patient” Timothy Ray Brown and the anonymous London Patient received — will not be a likely treatment option for most. Also important: as a report in The New York Times pointed out, the London Patient was not the first attempt to replicate the success with the Berlin Patient, only the first that seems to have not failed.
How is remission different from cure?
Being cured would mean getting rid of the virus forever; remission would mean it is there, but under control for the time being. Before the second case was reported, Brown’s had been the only one of a cure. In all other attempts, the virus had come back after the patient stopped anti-HIV medication. The London Patient has been HIV-free for 18 months since he stopped taking drugs. To some that means a cure; however, as Dr Annemarie Wensing of the University Medical Centre Utrecht, who was quoted by The NYT, said, “We don’t have any international agreement on what time without viral rebound is necessary to speak about cure.”
Indeed, some patients have had remission even without a bone-marrow transplant. Their immune system appears to be successful in controlling the virus, even without drugs. But it is not clear how this happens.
When is a treatment based on this success expected?
In a decade perhaps, several specialists were being quoted as saying Wednesday. But that treatment would cover only those types of HIV that rely on the CCR5 surface protein to break into the immune cells. The X4 form of HIV, which uses a different protein, would not be tackled by treatment based on the delta 32 mutation.
While it would be premature to expect a cure or remission soon, the rapid progress in gene therapy and gene editing bring hope. The widely criticised Chinese doctor He Jiankui, has in fact, claimed to have modified the CCR5 protein in at least two children using CRISPR/Cas9 gene editing technology.