title: Characterization of HIV-1 drug resistance development through week 48 in antiretroviral naive subjects on rilpivirine/emtricitabine/tenofovir DF or efavirenz/emtricitabine/tenofovir DF in the STaR study (GS-US-264-0110).
abstract: BACKGROUND
  The Single-Tablet Regimen (STaR) study (GS-US-264-0110) is a 96-week phase 3b study evaluating the safety and efficacy of 2 single-tablet regimens, rilpivirine/emtricitabine/tenofovir DF (RPV/FTC/TDF), and efavirenz/emtricitabine/tenofovir DF (EFV/FTC/TDF) in treatment-naive HIV-1-infected subjects.
  
  
  METHODS
  Genotypic analyses (population sequencing) of HIV-1 protease and reverse transcriptase were performed at screening; subjects with pre-existing resistance to study drugs were excluded. The primary protocol-defined resistance analysis population (RAP) had genotypic/phenotypic analyses at failure and baseline for protease and reverse transcriptase.
  
  
  RESULTS
  At week 48, the primary RAP included 20/394 subjects (5.1%) receiving RPV/FTC/TDF and 7/392 subjects (1.8%) receiving EFV/FTC/TDF. In the RPV/FTC/TDF arm, isolates from 17/394 subjects (4.3%) developed nonnucleoside reverse transcriptase inhibitor (NNRTI) and/or nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations, and 16/17 isolates had both NNRTI and NRTI resistance mutations. In the EFV/FTC/TDF arm, isolates from 3/392 subjects (0.8%) developed NNRTI and/or NRTI resistance mutations. When stratified by baseline viral load of either ≤ 100,000 or >100,000 copies/mL, 5/260 (1.9%) versus 12/134 (9.0%) RPV/FTC/TDF-treated subjects and 2/250 (0.8%) versus 1/142 (0.7%) EFV/FTC/TDF-treated subjects developed resistant isolates, respectively. The presence of pre-existing NRTI- and NNRTI-associated resistance mutations not excluded at screening (not related to study drugs) did not impact treatment response to either regimen.
  
  
  CONCLUSIONS
  Among subjects in the primary RAP, resistance development to RPV/FTC/TDF consisted of NNRTI and NRTI mutations and was more frequent than resistance development to EFV/FTC/TDF. In subjects with baseline viral load ≤ 100,000 copies/mL, resistance development was low (<2%) for both RPV/FTC/TDF and EFV/FTC/TDF arms and less frequent compared with subjects with baseline viral load >100,000 copies/mL, for RPV/FTC/TDF.
authors: Gilead Sciences, Inc, Foster City, CA.
authors: Danielle P
authors: DP
authors: Porter
authors: Rima
authors: R
authors: Kulkarni
authors: Todd
authors: T
authors: Fralich
authors: Michael D
authors: MD
authors: Miller
authors: Kirsten L
authors: KL
authors: White
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D004338:Drug Combinations; D024882:Drug Resistance, Viral; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D015337:Multicenter Studies as Topic; D020125:Mutation, Missense; D017422:Sequence Analysis, DNA; D014481:United States
chemical_list: D019380:Anti-HIV Agents; D004338:Drug Combinations; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D016333:HIV Protease; C514803:p16 protease, Human immunodeficiency virus 1