Data Show Gilead's Quad Regimen for HIV Non-Inferior to Protease-Based Regimen at 48 Weeks in Second Pivotal Phase 3 Study
March 8, 2012
Seattle, Wash. -- Gilead Sciences, Inc. (Nasdaq: GILD) today announced full results from the second pivotal Phase 3 clinical trial (Study 103) of its Quad once-daily single tablet regimen of elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate for the treatment of HIV. The study found that the Quad was non-inferior to a protease-based regimen of ritonavir-boosted atazanavir (ATV/r) plus Truvada®(emtricitabine/tenofovir disoproxil fumarate) at 48 weeks of therapy among HIV-1 infected treatment-naive adults. These data were presented today in a poster session (Abstract #627) at the 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012) taking place in Seattle.
At 48 weeks of treatment in Study 103, Quad demonstrated comparable efficacy to the atazanavir-based regimen, with 90 percent of Quad patients compared to 87 percent of patients receiving ATV/r plus Truvada achieving HIV RNA (viral load) less than 50 copies/mL, using the U.S. Food and Drug Administration (FDA) snapshot algorithm (95 percent CI for the difference: -1.9 percent to +7.8 percent; predefined criterion for non-inferiority was a lower bound of a two sided 95 percent CI of -12 percent). Among patients with baseline HIV RNA greater than 100,000 copies/mL, Quad demonstrated similar efficacy, with 85 percent of Quad patients compared to 82 percent of patients receiving ATV/r plus Truvada achieving viral load less than 50 copies/mL.
"The 90 percent response rate demonstrated by the Quad in this study is one of the highest we have seen in any large, randomized HIV clinical trial of an antiretroviral regimen conducted to date," said Edwin DeJesus, MD, Medical Director of the Orlando Immunology Center, Orlando, Florida, and principal investigator of Study 103. "This result is a strong indication of the potential benefit that an integrase-based single tablet regimen could offer patients starting HIV treatment."
The discontinuation rate due to adverse events was comparable among patients taking Quad (4 percent) and the atazanavir-based regimen (5 percent). Elevated bilirubin levels (grades 3-4) were observed in 1 percent of patients in the Quad arm, compared to 58 percent in the atazanavir-based arm. Quad patients also experienced significantly lower increases in triglyceride levels (+8 mg/dL) compared to those receiving the atazanavir-based regimen (+23 mg/dL).
The Phase 3 clinical program for Quad includes two studies (Studies 102 and 103) that each evaluate the Quad regimen versus a standard of care among HIV-1 infected antiretroviral treatment-naive adults. Gilead announced topline results from Study 103 on September 19, 2011. Study 102, a randomized, double-blind clinical trial comparing the efficacy, safety and tolerability of Quad versus Atripla® (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) is ongoing, and the company announced 48-week results from this study on March 7, 2012 at CROI 2012.
Gilead submitted a U.S. New Drug Application for Quad on October 27, 2011, and the FDA has set a target review date under the Prescription Drug User Fee Act of August 27, 2012. On November 24, 2011, the company submitted a Marketing Authorisation Application for the product to the European Medicines Agency, whose review may be complete by the end of 2012.
Study 103 is a randomized (1:1), double-blind Phase 3 clinical trial comparing the efficacy, safety and tolerability of the Quad (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) (n=353) versus atazanavir 300 mg boosted by ritonavir 100 mg (ATV/r) plus Truvada (n=355) among HIV-infected treatment-naive adults with baseline HIV RNA levels greater than 5,000 copies/mL. The primary endpoint of the study is the proportion of patients achieving HIV RNA levels less than 50 copies/mL at 48 weeks of treatment, per the FDA snapshot algorithm. Secondary objectives will evaluate the efficacy, safety and tolerability of the treatment regimens through 192 weeks of treatment.
At baseline, patients in the Quad arm had a median HIV RNA of 4.88 log10 copies/mL and mean CD4 cell count of 364 cells/mm3. Patients in the atazanavir-based arm had a median HIV RNA of 4.86 log10 copies/mL and mean CD4 cell count of 375 cells/mm3. Across both arms, 41 percent of patients had HIV RNA greater than 100,000 copies/mL and 13 percent had CD4 counts less than or equal to 200 cells/mm3.
Patients in both arms experienced similar increases in CD4 cell counts (mean increase of 207 cells/mm3 for Quad and 211 cells/ mm3 for ATV/r plus Truvada). The virologic failure rate was 5 percent for both treatment regimens based on a component of the FDA snapshot analysis.
The most common adverse events occurring in at least 10 percent of patients in either arm of the study were diarrhea, nausea, upper respiratory infection, headache, fatigue and ocular icterus. The most common adverse events were similar across both treatment arms with the exception of ocular icterus (associated with elevated bilirubin levels), which was less frequent for the Quad arm than for the ATV/r plus Truvada arm of the study (1 and 14 percent, respectively).
With the exception of elevated bilirubin levels among patients receiving atazanavir-based therapy, grade 3-4 laboratory abnormalities were similar for both treatment regimens, with only elevated creatine kinase occurring in more than 5 percent of patients (6 percent for the Quad and 7 percent for ATV/r plus Truvada). Lipid increases were comparable between study arms, with the exception of the higher triglyceride elevations observed among patients taking the atazanavir-based regimen (p=0.006).
Both treatment regimens had comparable renal profiles, with median increases in serum creatinine of 0.12 mg/dL for the Quad and 0.08 mg/dL for ATV/r plus Truvada. Bone safety profiles were also similar, with a median change from baseline in hip bone density of -2.87 percent for the Quad and -3.59 percent for ATV/r plus Truvada (p=0.12).
The study is ongoing in a blinded fashion. After week 192, subjects will continue to take their blinded study drug until treatment assignments have been unblinded, at which point all subjects will be given the option to participate in an open-label rollover extension and receive the Quad single tablet regimen. Additional information about the study can be found at www.clinicaltrials.gov.
The Quad, elvitegravir and cobicistat are investigational products and their safety and efficacy have not yet been established.
This article was provided by Gilead Sciences, Inc..
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