Renal impairment, including cases of acute renal failure and Fanconi syndrome (renal tubular injury with severe hypophosphatemia), has been reported with the use of TDF, a component of STRIBILD, and with the use of STRIBILD [see Adverse Reactions (6.2)].

In the clinical trials of STRIBILD over 144 weeks, 13 (1.9%) subjects in the STRIBILD group (N=701), 8 (2.3%) subjects in the atazanavir (ATV) + ritonavir (RTV) + TRUVADA® (emtricitabine 200 mg/TDF 300 mg) group (N=355), and no subjects in the ATRIPLA® (efavirenz 600 mg/emtricitabine 200 mg/TDF 300 mg) group (N=352) discontinued study drug due to a renal adverse reaction. Of these discontinuations, 8 in the STRIBILD group and 1 in the ATV+RTV+TRUVADA group occurred during the first 48 weeks. Four (0.6%) subjects who received STRIBILD developed laboratory findings consistent with proximal renal tubular dysfunction, leading to discontinuation of STRIBILD during the first 48 weeks of treatment. Two of the four subjects had renal impairment (i.e., estimated creatinine clearance less than 70 mL per minute) at baseline. The laboratory findings in these 4 subjects improved but did not completely resolve in all subjects upon discontinuation of STRIBILD. Renal replacement therapy was not required for these subjects. One (0.3%) subject who received ATV+RTV+TRUVADA developed laboratory findings consistent with proximal renal tubular dysfunction, leading to discontinuation of ATV+RTV+TRUVADA after Week 96.

STRIBILD should be avoided with concurrent or recent use of a nephrotoxic agent (e.g., high-dose or multiple nonsteroidal anti-inflammatory drugs [NSAIDs]) [see Drug Interactions (7.4)]. Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in HIV-infected patients with risk factors for renal dysfunction who appeared stable on TDF. Some patients required hospitalization and renal replacement therapy. Alternatives to NSAIDs should be considered, if needed, in patients at risk for renal dysfunction.

Persistent or worsening bone pain, pain in extremities, fractures, and/or muscular pain or weakness may be manifestations of proximal renal tubulopathy and should prompt an evaluation of renal function in at-risk patients.

Prior to initiation and during use of STRIBILD, on a clinically appropriate schedule, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue STRIBILD in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome. Initiation of STRIBILD in patients with estimated creatinine clearance below 70 mL per minute is not recommended [see Dosage and Administration (2.1)].

Although cobicistat (a component of STRIBILD) may cause modest increases in serum creatinine and modest declines in estimated creatinine clearance without affecting renal glomerular function [see Adverse Reactions (6.1)], patients who experience a confirmed increase in serum creatinine of greater than 0.4 mg per dL from baseline should be closely monitored for renal safety.

The emtricitabine and TDF components of STRIBILD are primarily excreted by the kidney. STRIBILD should be discontinued if estimated creatinine clearance declines below 50 mL per minute as dose interval adjustment required for emtricitabine and TDF cannot be achieved with the fixed-dose combination tablet [see Use in Specific Populations (8.6)].