Drug recycling using viral fitness

Even if you have used every drug, you may not have developed complete resistance to all of them. 

More importantly, complete resistance is unlikely to be on every virus. Some of your HIV may be resistant to nukes but different virus may be resistant to PIs. Each resistant virus is also likely to be less fit or active (compared to non-resistant HIV).

Some researchers think that viral fitness can be used to control HIV by cycling different combinations. This is a theoretical strategy for someone with resistance to many classes.

This might also work because there are now many classes of drugs to cycle.

The effect of each drug or combination change would be to keep changing the type of resistance. Early resistance is usually related to reduced viral fitness for at least the first 4—8 weeks.

Reduced fitness is usually overcome by new mutations, so you want to change before this occurs. Cycles could be weekly or monthly.

This could be a new and important approach for people with no other options. It could also use fewer drugs in each combination.

An Italian study reported this working by changing combination whenever viral load reached 10,000 c/mL.

This was many years ago. The recent approval of new drugs make this a strategy that hopefully no-one needs to try.

Last updated: 1 August 2021.