By RTT News, March 05, 2013, 12:31:00 PM EDT
(RTTNews.com) - Gilead Sciences Inc. ( GILD ) Tuesday announced detailed 24-week results from a Phase 2 trial evaluating a once-daily single tablet regimen containing tenofovir alafenamide, or TAF, for the treatment of the deadly HIV-1 infection.
Results from the Phase 2 trial, dubbed Study 102, showed that a regimen of TAF 10 mg/elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 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 at 24 weeks of treatment.
The findings were presented at the 20th Conference on Retroviruses and Opportunistic Infections taking place in Atlanta.
"Given that HIV is now a chronic disease that can be managed with life-long therapy, there remains a need for new treatment options that are well tolerated," said Andrew Zolopa, an investigator for Study 102.
"In this study, a TAF-based single tablet regimen achieved comparable viral suppression to Stribild while demonstrating improvement in renal and bone safety indicators."
In Study 102, HIV-positive treatment-naÃ¯ve adult patients were randomized (2:1) to receive the investigational TAF-based regimen or Stribild. At 24 weeks, 87 percent of patients taking TAF and 90 percent of patients taking Stribild achieved HIV RNA (viral load) less than 50 copies/mL.
There were no statistically significant differences in the frequency and nature of Grades 3-4 laboratory abnormalities, and the frequency and nature of adverse events were similar between the two arms. Both regimens were generally well tolerated.
Norbert Bischofberger, Gilead's chief scientific officer, said, "Our Phase 3 program for TAF is enrolling rapidly, and we look forward to sharing initial results from the first pivotal study in 2014."
In January 2013, Gilead announced the initiation of two Phase 3 trials, Studies 104 and 111, which are examining TAF/elvitegravir/cobicistat/emtricitabine compared to Stribild among HIV patients new to therapy. Topline results from Study 102 were announced in October 2012.
Study 102 is a randomized, double-blind 48-week clinical trial evaluating the efficacy and safety of a once-daily single tablet regimen containing TAF 10 mg/elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg compared to Stribild (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) among HIV-1 infected treatment-naÃ¯ve adults with HIV RNA levels greater than or equal to 5,000 copies/mL and CD4 cell counts greater than 50 cells/mm3. Bone mineral density was assessed in all patients by DEXA scans at baseline and at 24 weeks of treatment.
The primary endpoint of the study is the percentage of patients with HIV RNA levels less than 50 copies/mL at week 24, per the FDA snapshot algorithm.
At baseline, patients receiving the TAF-based regimen had a median HIV RNA of 4.55 log10 copies/mL and median CD4 cell count of 385 cells/mm3. Patients receiving Stribild had a median HIV RNA of 4.58 log10 copies/mL and median CD4 cell count of 397 cells/mm3.
At week 24, mean CD4 cell count increases from baseline were 163 cells/mm3 in the TAF arm and 177 cells/mm3 for Stribild.
Both regimens were generally well tolerated, and discontinuations due to adverse events were similar in both treatment arms.
The frequency of adverse events was similar in both treatment arms, and more than 90 percent of adverse events were Grades 1-2. The most common adverse events occurring in at least 5 percent of TAF patients were nausea, diarrhea, fatigue, headache, upper respiratory tract infection, and flatulence.
There were no treatment-related serious adverse events in either treatment arm.
The study is ongoing. After week 48, patients will continue to take their blinded study drug until treatment assignments have been unblinded, at which point all will be given the option to participate in an open-label rollover extension and receive the TAF-based single tablet regimen.
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