The most common adverse events occurring in greater than or equal to 10 percent of patients in either treatment arm included jaundice (21 percent in the cobicistat arm vs. 16 percent in the ritonavir arm), ocular icterus (18 percent in both arms), nausea (18 percent vs. 16 percent), diarrhea (15 percent vs. 20 percent), headache (11 percent vs. 16 percent), nasopharyngitis (11 percent vs. 15 percent), hyperbilirubinemia (11 percent vs. 10 percent) and upper respiratory infection (10 percent vs. 8 percent).The median increases in serum creatinine were 0.13 mg/dL for the cobicistat arm and 0.09 mg/dL for the ritonavir arm at 48 weeks (p<0.001). Discontinuation rates due to renal adverse events were low and comparable in both arms (1.7 percent in the cobicistat arm vs. 1.4 percent in the ritonavir arm). Median changes from baseline to Week 48 in total cholesterol were +4 mg/dL and +10 mg/dL (p=0.081); median changes in low-density lipoprotein (LDL or “bad” cholesterol) were +5 mg/dL and +8 mg/dL (p=0.32); and median changes in triglycerides were +16 mg/dL and +24 mg/dL (p=0.63) for patients in the cobicistat and ritonavir arms, respectively. Median increases in high-density lipoprotein (HDL or “good” cholesterol) were similar in the cobicistat and ritonavir arms (+4 mg/dL vs. +3 mg/dL, p=0.69). Study 114 is ongoing in a blinded fashion. Additional information about the study can be found at www.clinicaltrials.gov. About Cobicistat Cobicistat is Gilead’s proprietary potent mechanism-based inhibitor of cytochrome P450 3A (CYP3A), an enzyme that metabolizes drugs in the body. Unlike ritonavir, cobicistat acts only as a pharmacoenhancer and has no antiviral activity. Pharmacokinetic studies have demonstrated that cobicistat boosts the widely prescribed protease inhibitors atazanavir and darunavir. About Quad The Quad contains elvitegravir, cobicistat (a pharmacoenhancing or “boosting” agent that enables once-daily dosing of elvitegravir), and Truvada (emtricitabine and tenofovir disoproxil fumarate). In October 2011, Gilead submitted a New Drug Application to FDA for the Quad for the treatment of HIV. FDA has set a target action date for the Quad under the Prescription Drug User Fee Act (PDUFA) of August 27, 2012.