Gilead Sciences, Inc. (Nasdaq: GILD) today announced 48-week results from a Phase 2 study (Study 102) evaluating an investigational once-daily single tablet regimen containing tenofovir alafenamide (TAF) for the treatment of HIV-1 infection. At 48 weeks, a regimen of elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/TAF 10 mg was found to be similar to Stribild ® (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) based on the percentage of patients with HIV RNA levels less than 50 copies/mL, and was associated with more favorable renal and bone safety markers. These findings were presented today in a latebreaker session (Abstract #H-1464d) at the 53 rd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2013) taking place in Denver. “These results suggest that TAF has the potential to be an important advance for people living with HIV,” said Paul Sax, MD, Clinical Director of the Division of Infectious Diseases at Brigham and Women’s Hospital, Boston, Professor of Medicine at Harvard Medical School, and an investigator for Study 102. “In this study, the TAF-based regimen matched Stribild’s high viral suppression and demonstrated a favorable safety profile with respect to renal and bone changes.” In Study 102, 170 HIV-positive treatment-naïve adult patients were randomized (2:1) to receive the investigational TAF-based regimen or Stribild. At 48 weeks, 88.4 percent (n=99/112) of patients taking TAF and 87.9 percent (n=51/58) of patients taking Stribild achieved HIV RNA (viral load) less than 50 copies/mL, based on the FDA snapshot algorithm (intent-to-treat analysis; stratum-adjusted difference between TAF and Stribild: -1.0 percent, p=0.84, 95 percent CI for the difference: -12.1 percent, 10.0 percent). No drug resistance was observed in patients receiving the TAF-based regimen. Both regimens were generally well tolerated. There were no treatment-related serious adverse events. There were numeric differences in laboratory abnormalities of renal and bone markers, which favored the TAF-based regimen. There was a statistically significant difference in the median change in estimated glomerular filtration rate (eGFR) from baseline to week 48, with eGFR decreasing by -5.5 mL/min in the TAF arm compared to a decline of -10.0 mL/min in the Stribild arm (p=0.041). Additionally, there was a significantly smaller median percentage decrease in bone mineral density from baseline to week 48 for the TAF-based regimen compared to Stribild (-1.00 vs. -3.37 (p<0.001) for the lumbar spine and -0.62 vs. -2.39 (p<0.001) for the hip). There were no pathological bone fractures in either arm of the study.