CROI 2018: a quick round up of the latest HIV and TB research developments
Get your head around three of the biggest talking points from this year’s Conference on Retroviruses and Opportunistic Infections (CROI).
The annual Conference on Retroviruses and Opportunistic Infections (CROI) is one of the biggest dates in the HIV calendar, bringing together researchers from all around the world to share the latest HIV research. We bring you highlights in an easily digestible form, so you can get to grips with the biggest talking points from the conference.
1. Ground-breaking new TB prevention treatment
In what has been described as a ‘game changing’ new finding, researchers have discovered that effective tuberculosis (TB) prevention can be delivered in one month. The current preventative treatment being offered, isoniazid, must be taken every day for nine months, and in high TB/HIV burden countries the World Health Organization recommends that it is taken for 36 months.
These long treatment durations have been a major barrier to the success of TB prevention efforts. Professor Chaisson of John Hopkins University, commented that across the world access and adherence to TB prevention is still ‘abysmal’. As a result TB remains the leading cause of death among people living with HIV, despite being both preventable and curable.
Combining Isoniazid with the antibiotic Rifapentine over the course of one month provided the same treatment benefits as nine months of Isoniazid. This means there is finally a TB prevention option that is workable for patients and healthcare providers alike.
The researchers commented that they thought the study was large enough and clear enough to form the basis of new treatment guidelines already and that the only issue with this new life-saving option would be expense: at the moment the one month regime costs $72 per person, and is only manufactured by one company.
2. Women much more vulnerable to HIV during pregnancy and after giving birth
Research presented at CROI also provided new insights into HIV risk during and after pregnancy showing that biological changes during this period can put women more at risk of HIV.
In the past it has been unclear how pregnancy affects HIV risk. However, this new study clears up some of the confusion, providing the largest sample size to date (2,751 serodiscordant couples) as well as a calculation of the probability of HIV transmission per sex act.
The researchers found that during pregnancy and just after birth women faced an average of three times greater HIV risk than at other times. The risk was greatest in the months following birth, when transmission was 4.18 times more likely.
The study suggests this elevated risk is a result of biological changes during this time, having controlled for other factors such as reduced condom use. Further research is needed to understand which biological factors are responsible, but the researchers speculate that it might be due to changes in hormones or immune function.
These findings have especially important ramifications for mother-to-child transmission during breastfeeding, stressing the need for regular testing throughout this period. It also raises questions around whether PrEP should be targeted at women during pregnancy and in the months after giving birth.
3. Functional HIV cure research gets one step closer
In the search for a functional HIV cure researchers are looking for ways to maintain viral suppression without people having to take daily doses of antiretroviral medicines. Current antiretroviral treatments for HIV can stop the virus from multiplying but can’t get rid of ‘hidden reservoirs’ of HIV. This is where the virus will lie dormant in infected immune cells. In this state HIV is hidden because it isn’t multiplying or actively attacking the immune system.
Using a strategy known as ‘Kick and Kill’, researchers are trying to identify and activate these reservoirs, so that they can be targeted and attacked with new medicines. CROI 2018 saw researchers report on one of the most recent ‘kick and kill’ attempts. Scientists have used a ‘GS-9620’, a drug that activates a part of the immune system responsible for recognising and responding to viruses, alongside a ‘neutralising’ antibody called PGT121.
Trials of this combination in rhesus monkeys have shown that this cocktail is able to maintain viral suppression in rhesus macaque monkeys over a period of at least three months without taking ART. In over half the monkeys this was maintained even longer, for as much as six months.
Even when monkeys had viral rebounds – where levels of HIV started to grow and become detectable again – often their immune function was able to fight the virus again without having to restart treatment. Even after remission the virus was still at a far lower level than before and viral DNA levels in their lymph nodes were still at lower levels, suggesting that some of the viral reservoirs had actually been depleted and some level of immune control sustained.
This is still a long way from a cure, especially since at the moment it has only been shown to have these effect on monkeys, but nevertheless it gives hope that long-term viral remission might be possible.
For more detail on these and other stories from CROI take a look at Aidsmap’s conference coverage.