Objective:

To study HIV resistance in Hispanic antiretroviral therapy (ART)-experienced patients, and response after genotype (GT)-guided ART changes.

Methods:

A retrospective analysis of ART-experienced patients seen in an outpatient clinic in Puerto Rico, assessment of resistance by GT, and evaluation of virological response after GT-guided ART change.

Results:

A total of 84 patients, all ART-experienced Hispanic men, had 92 GTs performed for ART failure. Seventy-three per cent had >1 prior change in their ART, 89% were using >3 ART drugs. Prior exposure to all three drug classes was seen in 35% patients, to NRTI + PI in 38%, to NRTI + NNRTI in 18% and to only NRTI in 9%. Mean ART length was 38 (range 3–60) months. Mean VL was 40 000 (811–750 000). Resistance by GT to all three drug classes was seen in 26% of patients, to two classes in 48% and to one class in 14%. Twelve per cent of patients had wild-type virus; 86% had resistance to NRTI, 55% to PI, and 46% to NNRTI. Fifty-eight patients had a GT-guided ART change. VL decrease >0.5 log was seen in 57% patients within 16 weeks. Thirty-four per cent reached VL <400. New ART included two sensitive drugs in 69% patients, only 26% had >2 sensitive drugs. Success in patients having used <3 drugs in the past was 100%, those having used 3–7 drugs 59%, and those having used >7 drugs 20% (P = 0.05). Patients with resistance to <2 drug classes were more likely to have virological success vs. those with higher resistance (71% vs. 57%), but not significantly so. Success did not depend on the number of sensitive drugs or on the number of new drugs added.

Conclusions:

Genotype-guided ART change was associated with 59% virological success in this clinic, despite having a heavily ART-experienced and heavily resistant population. Success was predicted by the number of drugs the patient had previously used. There was a trend to better success in those with <2 ART drug class resistance. Success was not predicted by the number of sensitive drugs nor the number of new drugs in the patient's ART.