Patients Becoming Resistant to Common HIV Drugs: Is There Cause for Worry?

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In a study published in the journal Lancet Infectious Diseases, HIV researchers found a surprisingly high rate of drug resistance in patients taking tenofovir—the most commonly used medication to treat HIV in the U.S. and most parts of the world. Tenofovir is a component of six FDA-approved therapies for treatment and prevention of HIV.

Is this cause for concern?

Drug Resistance is Not New

We have known about drug resistance since the late 1980’s with AZT, D4T, and some of the older HIV medications. This is why early attempts at treating patients with just one or two drugs did not work. The virus mutated and made these drugs eventually ineffective.

The use of three-drug therapies starting in 1996 appeared to prevent this from happening, although resistance still does occur—mainly in patients who frequently miss doses of their daily HIV medications.

In this new study referred to as “TenoRes,” researchers at the University College London studied about 2,000 people from 36 countries whose HIV drug treatment had failed between 1998 and 2015. They found drug resistance to tenofovir much higher than expected, especially in sub-Saharan Africa where 57% of patients had tenofovir resistance.

This result is disconcerting because it has been thought that tenofovir was less prone to develop drug resistance than other compounds. This certainly has been our experience in the U.S. were tenofovir resistance appears to be less than 10%.

New Treatment Regimens Needed

The findings indicate a need to develop treatment regimens that will be less prone to this problem--one that should probably have been anticipated as an unavoidable outcome of the successful HIV drug rollout programs that helped to save millions of lives around the world in the past several decades. Some of the newer drug combination attempt to address this problem, but resistance to any HIV medication is always a possibility.

Resistance More Prevalent with Late Treatment

Another key finding of the study is that tenofovir resistance is more likely to develop in individuals who had low CD4+/T-cell cell counts because of late diagnosis. In other words, they already had AIDS.

We know from many other studies that the immune systems of people who start HIV treatment late often do not recover as well, and are more likely to develop drug resistance.

HIV Testing is Critical

Identifying individuals as HIV positive as efficiently and as soon as possible and beginning treatment offers the best chance of long-term success. We also know early treatment helps prevent spreading HIV to partners

The results of this study are a reminder that the problems of HIV drug resistance are very real, especially in developing countries, and there is a need for baseline testing regardless of where one lives.

The Bottom Line

We need to strive for more widespread, effective screening so people with HIV can begin therapies sooner, reducing the likelihood of drug resistance.

Comprehensive Care offers walk-in, needleless HIV testing that is fast, free, and confidential. We offer the ORA Quick rapid HIV test that requires only an oral (mouth) swab. Results are available in 20 minutes.

Free HIV testing without an appointment is available Monday-Thursday, 9-11 a.m. and 1-4 p.m.; Friday 9-11 a.m. at 554 North Duke St., 3rd floor, Lancaster, across from Lancaster General Hospital.

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