Resistance remains a problem in treatment failure.

Area of Science:

• Virology
• Infectious Diseases
• Clinical Pharmacology

Background:

• Drug resistance in HIV clinical trials is rare, often overshadowed by screening for transmitted drug resistance.
• Assumptions of decreasing HIV drug resistance are challenged by real-world data outside controlled trial settings.

Purpose of the Study:

• To evaluate trends in HIV drug resistance among patients experiencing treatment failure outside of clinical trials.
• To assess the prevalence of resistance to various drug classes in a real-world patient cohort.

Main Methods:

• Analysis of the MIB database containing data from 2876 HIV-infected patients, including treatment history and laboratory parameters.
• HIV-1 protease and reverse transcriptase sequences were analyzed using the HIV-GRADE drug resistance algorithm.
• Treatment failure on integrase inhibitor regimens was considered indicative of resistance due to limited genotypic testing availability.

Main Results:

• Between 2009 and 2012, the percentage of patients with no detectable drug resistance decreased from 61% to 52%.
• Resistance to three or more drug classes increased from 2.4% in 2009 to 14% in 2012.
• The proportion of patients with resistance to at least one drug class rose from 39% in 2009 to 48% in 2012.

Conclusions:

• Treatment failure in the studied cohort was frequently associated with HIV drug resistance.
• The increasing use of newer drug classes correlates with a rise in resistance to these agents.
• Multi-class drug resistance is becoming more prevalent, posing a significant clinical challenge.