Nucleoside drugs can be left out of combinations for people with lots of drug resistance

With modern anti-HIV drugs, most people are able to find a safe and effective combination of drugs which they are able to take for several years.

Nonetheless a few people who have had problems with treatment in the past may have resistance to several classes of anti-HIV drugs. When changing treatment, choosing a new, effective treatment regimen can be tricky. The aim is to put together a combination that includes two or preferably three fully active drugs.

Drugs from the nucleoside reverse transcriptase inhibitors (NRTI) class of drugs are usually a standard part of all HIV drug combinations. Because of this, people who have previously tried several different combinations and had difficulties with them are likely to have resistance to drugs in this class. It’s therefore questionable whether including them in a new combination has any benefit.

A new study has looked at whether it is possible to leave them out.

Each of the 360 Americans taking part had already tried at least two different drug combinations, had some resistance and had not achieved an undetectable viral load.

A number of newer drugs, from new drug classes, are now available and are able to work against resistant virus. All participants started a new drug combination involving two or three active drugs. For example these included the integrase inhibitor raltegravir (Isentress), the protease inhibitor darunavir (Prezista) or the non-nucleoside reverse transcriptase inhibitor etravirine (Intelence).

Half the participants were randomised to add in a nucleoside drug, while half left it out.

After one year, the results showed no substantial difference in results. In both groups, around seven in ten participants had an undetectable viral load and were continuing to take their treatment.

These results are specific to people with problems of drug resistance – it isn’t necessarily safe for people in other situations to drop the nucleoside drugs. Nonetheless, several other studies have recently looked at treatment simplification strategies for people in a range of situations.

The potential benefits of taking fewer drugs could include the drugs being easier to take, having fewer side-effects and costing less.

There’s more information on HIV treatment for people in this situation in NAM’s factsheets on Changing treatment because of resistance and Options for the highly treatment-experienced.