HIV-positive people with few or no remaining antiretroviral options may still benefit from staying on a drug regimen that is no longer controlling the virus, according to new data published in the October 15 issue of Clinical Infectious Diseases.

A growing number of people are on HIV treatment regimens that are unable to keep their virus undetectable, but can’t construct a new regimen because their virus is resistant to all the available drugs. Their only option is to stay on the failing regimen and take the risk that their virus may develop even more resistance mutations, while they wait for new HIV drugs to be developed. Tejal Gandhi, MD, of the University of Michigan Health System, and her colleagues sought to determine the risks and benefits for people confronted with this dilemma if they stay on their failing regimen.

The team enrolled 47 people with HIV who remained on a failing treatment regimen. The team observed them for 48 weeks, looking for evidence of further immunologic failure—a CD4 count drop of 25 percent or more that persisted for at least three months. They also looked for evidence of further virologic failure—a persistent increase in viral load of at least half a log.

After 48 weeks, 43 percent of the study participants had immunologic failure and 21 percent had virologic failure. Of 27 people whose virus was tested for drug resistance, 63 percent of them developed a new mutation to at least one of the classes of HIV drugs. This means that a majority of people who continue to take failing HIV drug regimens may still be protected from disease progression. They do, however, run the risk of developing new drug-resistance mutations.