High frequency of antiviral drug resistance and non-B subtypes in HIV-1 patients failing antiviral therapy in Cuba.

BACKGROUND: Emergence of HIV-1 drug resistance may limit the sustained benefits of antiretroviral therapy (ART) in settings with limited laboratory monitoring and drug options. OBJECTIVES: Surveillance of drug resistance and subtypes in HIV-1 patients failing ART in Cuba. STUDY DESIGN: This study compiled data of ART-experienced HIV-1 patients attending a clinical center in Havana in 2003 and 2009-2011. The first period included results of a cross-sectional study, whereas in the second period genotyping was performed as part of routine care. Drug resistance mutations and levels were determined using HIVdb version 6.0.9. RESULTS: Seventy-six percent received solely ART containing at least 3 drugs, of which 79.1% ever receiving unboosted protease inhibitors (PI). Patients from 2009 to 2011 were longer treated and exposed to more ART regimens. Subtype B (39%) and CRF19_cpx (18%) were the most prevalent genetic forms. Subtype distribution did not change significantly between both periods, except for BG recombinants that increased from 6% to 14%. Nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside RTI (NNRTI) and PI mutations were present in 69.5%, 54.8% and 44.4%. Full-class resistance (FCR) to NRTI, NNRTI, PI and multidrug resistance (MDR) were detected in 31.8%, 37.9%, 18.5% and 15.4%. FCR to NRTI, NNRTI, PI and MDR were present in 9.8%, 14.1%, 0%, 0% after first-line failure and in 19.8%, 20.8%, 2.9% and 2.9% after second-line failure. CONCLUSIONS: Our study found a high prevalence of drug resistance and supports the need for appropriate laboratory monitoring in clinical practice and access to drug options in case of virological failure.