HIV Transmitted Drug Resistance in the Philippines: The Case for Baseline Genotyping and Drug Resistance Testing

Abstract

BACKGROUND: The Philippines has one of the fastest growing HIV epidemics in the world. Parallel to the increase is a shift in HIV subtype from B to CRF01_AE. No transmitted drug resistance (TDR) surveillance has ever been conducted. With the widespread rollout of antiretrovirals and the limited repertoire of 6 drugs (tenofovir, lamivudine, zidovudine, nevirapine, efavirenz, lopinavir/ritonavir) makes TDR monitoring imperative. In addition, a high rate of hepatitis B (HBV) co-infection (17%) in the general population raises the risk of TDR with prior NRTI monotherapy. METHODS: Following IRB approval, we performed TDR surveillance at the Philippine General Hospital, one of the largest tertiary referral centers in the country. Treatment-naïve patients had their HIV RT and PR genes sequenced using WHO approved-protocols for HIV genotyping. Generated sequences were analyzed using the Stanford Drug Resistance Database. Pertinent demographic and clinical data were collected. The current results represent year 1 of the study. RESULTS: 95 treatment naïve patients were analyzed. Median age was 30 years (range 20–68). There were 88 males and 7 females. Median CD4 count was 90 cells/mL (range 0–936) and median viral load was 1792000 copies/mL. 18 patients were co-infected with HBV, but all denied previous HBV treatment. CONCLUSION: The TDR rate for HIV in the Philippines is 6.3%. This is above the threshold for recommending baseline TDR genotyping for all local HIV patients. All HIV with TDR were subtype CRF01_AE, and this may signal a higher risk of TDR as the epidemic shifts further to a non-B subtype.