HIV update - 6th July 2016

Three times a week Atripla

A preliminary, small study presented at the ASM Microbe conference suggests that it might be possible to take a single tablet of HIV treatment just three times a week and continue to maintain an undetectable viral load. The approach now needs to be tried out in a larger group of people and for a longer length of time – the study has only followed people for less than six months.

There are many reasons why people would prefer to take HIV treatment less often, including concerns about side-effects. The approach would also be attractive to health services trying to keep their budgets under control. On the other hand, a non-daily regimen might make it harder to remember to take pills consistently. And with fewer overall doses, a missed dose would be more likely to cause problems.

This kind of approach wouldn’t work with all anti-HIV drugs. Some drugs are cleared by the body quite quickly, meaning that they definitely need to be taken once or twice a day. Other drugs, such as efavirenz, stay in the bloodstream for longer, potentially making less frequent dosing feasible. Efavirenz is a mainstay of HIV treatment and is included in the tablets Atripla, Sustiva and Stocrin.

Previous studies have suggested that it is safe to take an efavirenz-based treatment for just five days a week and to miss the doses that would be taken at weekends. This has been tested in adults and adolescents.

The new study involved people who were already taking Atripla (efavirenz, tenofovir and emtricitabine) and already had an undetectable viral load. Half of the 61 patients continued to take it daily, while the other half were asked to take it only on Mondays, Wednesdays and Fridays.

Six months later, everyone in the study still had an undetectable viral load.

But people in the group taking the drug three times a week said that they were sleeping better and there were signs that the regimen might be better for their kidneys and bones. Adherence was good and people in this group said they preferred it to daily dosing.

This was a small study. The researchers now plan to continue it for three years to see if less frequent Atripla can be safely used over a longer period.

Weekly injections

The same conference also heard about another study aiming to give new, simpler treatment options to people with an undetectable viral load.

In this case, the new treatment was not based on existing antiretroviral drugs, but an injection of PRO 140, a monoclonal antibody that blocks HIV entering into cells. This only works for individuals who have a strain of HIV which uses the CCR5 co-receptor to enter cells. A test to see if this is the case is needed before this treatment can be used.

In this study, people who already had an undetectable viral load stopped taking their existing HIV treatment and started to have injections once a week of PRO 140. They were trained to inject themselves.

This was an even smaller study and it was not randomised, meaning that there was no comparison group of people who continued with their usual treatment.

But of 14 people who took the injections for over a year, ten were able to maintain an undetectable viral load. Four people did have a viral rebound and had to go back to their previous treatment. Side-effects were minimal.

Reducing HIV treatment to an injection just once a week would be very attractive for many people if the injection is convenient and well tolerated. But, again, the approach needs to be tested in much larger studies.