HIV treatment – tropism testing
New European guidance has been issued about the use of a test to check if a person would benefit from treatment with the anti-HIV drug, maraviroc (Celsentri).
This drug belongs to a class of antiretrovirals called CCR5 antagonists (or CCR5 inhibitors).
It stops the virus from binding to the surface of CD4 cells by blocking what’s called a CCR5 co-receptor.
Most people with HIV have virus that uses this co-receptor. But many individuals who have a low CD4 cell count, or who have taken a lot of HIV treatment in the past, have virus that uses a different co-receptor called CXCR4.
A test called a tropism test can show which co-receptor the virus present in someone's body uses.
The new guidance stresses that a person must have this test before starting treatment with maraviroc. Patients should only take maraviroc if their virus uses the CCR5 co-receptor.
The guidance also provides information on the type of test to be used, and on the interpretation of test results.
Maraviroc is licensed in Europe for people who are changing HIV treatment, either because their viral load is detectable, or because of side-effects. In the US it’s also been approved for people who are starting HIV treatment for the first time.
HIV care for immigration detainees
The UK Border Agency (part of the Home Office) oversees ten Immigration Removal Centres (IRCs). They are prison-like structures, used for detaining people whose asylum claim is being considered, those whose claim for asylum has been refused, and migrants who the agency intends to remove from the country.
Like prisoners, immigration detainees are entitled to receive health care that is ‘equivalent’ to that normally available through the NHS.
Primary health care (such as GPs) is provided within an IRC by private contractors. They should arrange access to HIV treatment and other secondary care, which is provided by local hospitals.
In 2009, guidance on the health care of HIV-positive immigration detainees was published. This was intended to ensure that the standard of care was equivalent to that provided by the NHS.
But the new report has found that this advice was often being breached.
Many individuals experienced interruptions in their HIV treatment. Breaks in HIV treatment are not recommended, and unplanned interruptions can increase the risk of drug resistance. This can mean having to take a more complex combination of drugs that may be unavailable in the country a detainee is going to be deported to.
There were also breaches of confidentiality, and some people didn’t have appropriate medical tests. In addition, some people were deported without being given the required three months of HIV treatment.
HIV and sexual health – pre-cancerous anal lesions
A large number of HIV-positive gay men have pre-cancerous anal lesions, new research has shown.
Some strains of human papillomavirus (HPV) can cause cell changes and lesions in the anus that can ultimately lead to anal cancer. These lesions are graded according to their severity, and more severe or high-grade lesions are called AIN 2 or 3.
Tests can check for pre-cancerous cell changes.
Research conducted in HIV-positive gay men who were taking – or about to start – HIV treatment showed that 30% had high-grade anal lesions when they entered the study.
The study lasted three years, and during this time a third of men developed new high-grade lesions.
Older age, a low nadir (lowest-ever) CD4 cell count, and infection with HPV strains 16 and/or 18 were all associated with an increased risk of high-grade pre-cancerous lesions.
But there was some evidence that taking HIV treatment for a long time had a protective effect.
“This suggests that, although one cannot fully recover from HIV-induced immune deficiency, [HIV treatment] could have some beneficial effect in reducing the risk of AIN-2,3” comment the researchers.
They recommend that screening for pre-cancerous lesions should be especially targeted at men who had a low nadir CD4 cell count.
Even though many of the men had pre-cancerous cell changes, anal cancer was rare. This suggests that the presence of pre-cancerous lesions doesn’t necessarily mean that cancer will develop.
Nevertheless, it’s important to detect these cell changes as early as possible. This means that treatment can be provided promptly.
Viral load and infectiousness
There has been a lot of excitement – and debate – about the potential of HIV treatment to control the epidemic.
A number of studies have shown that very few new infections originate in people who are taking anti-HIV drugs and who have an undetectable viral load.
There’s also some evidence that increasing the number of people with HIV who are taking treatment has helped slow the epidemic in San Francisco and the Canadian province of British Columbia.
Therefore, some have advocated an approach called 'test and treat' as a way of stopping the epidemic.
But the new research has shown this is likely to be insufficient.
Researchers calculated that only 19% of patients with HIV in the US had an undetectable viral load.
In an editorial accompanying the study a senior HIV doctor from the Netherlands suggested that treatment should be incorporated into a wider strategy to combat the spread of HIV – or 'combination prevention.'
He commented, “It is unlikely that ‘test and treat’ strategies by themselves, even if vigorously and comprehensively pursued, will be sufficient to end the epidemic. It should be clear that ‘combination HIV prevention’, using a mix of available prevention tools, including ‘test and treat’ strategies, in a context-specific manner based on knowledge about local, national, and regional epidemics, is the way forward.”