Gilead Announces Results From First Study to Evaluate Switching to F/TAF-Based Regimens from Truvada® (F/TDF)-Based Regimens

Gilead Sciences, Inc. (NASDAQ:GILD) today announced 48-week results from a Phase 3 study (Study 1089) evaluating the safety and efficacy of switching virologically suppressed HIV-1 infected adult patients from regimens containing emtricitabine and tenofovir disoproxil fumarate (F/TDF) (Truvada^®) to regimens containing the investigational fixed-dose combination of emtricitabine and tenofovir alafenamide (200/10 mg and 200/25 mg) (F/TAF). At Week 48, the F/TAF-based regimens were found to be statistically non-inferior to the F/TDF-based regimens, based on percentages of patients with HIV-1 RNA levels less than 50 copies/mL. The study also demonstrated statistically significant improvements in renal and bone laboratory parameters among patients receiving F/TAF-based regimens. The data were presented in an oral session (Session O-2) at the 2016 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.

“This study reinforces the benefits we’ve consistently seen in other trials evaluating TAF-based regimens, including high rates of viral suppression and improvements in renal and bone lab safety parameters,” said Joel Gallant, MD, MPH, lead author of the Phase 3 study, Medical Director of Specialty Services at Southwest CARE Center in Santa Fe, N.M. “This is also the first study to demonstrate the potential versatility of F/TAF as a fixed-dose combination HIV treatment backbone that can be paired with a range of third agents to help meet the diverse needs of people living with HIV.”

TAF is a novel targeted prodrug of tenofovir that has demonstrated high antiviral efficacy similar to and at a dose less than one-tenth that of Gilead’s Viread^® (tenofovir disoproxil fumarate, TDF). TAF has also demonstrated improvement in surrogate laboratory markers of renal and bone safety as compared to TDF in clinical trials in combination with other antiretroviral agents. Data show that because TAF enters cells, including HIV-infected cells, more efficiently than TDF, it can be given at a much lower dose and there is 90 percent less tenofovir in the bloodstream.

In the study, 663 patients were randomized 1:1 in a blinded fashion either to switch to an F/TAF- or continue an F/TDF-based regimen (F/TAF, 333 patients; F/TDF, 330 patients) containing a third antiretroviral agent that was part of the participant's pre-existing treatment regimen. Dosing of F/TAF was dependent on the third agent: 200/10 mg with ritonavir-boosted protease inhibitors (darunvair, atazanavir and lopinavir) and 200/25 mg with unboosted third agents (raltegravir, dolutegravir, nevirapine, efavirenz, rilpivirine and maraviroc).

Through Week 48, similar high rates of virologic suppression (HIV-1 RNA <50 c/mL) were maintained in both treatment groups (F/TAF-based regimens, 94.3 percent; F/TDF-based regimens, 93.0 percent; difference in percentages: 1.3 percent, 95 percent CI: -2.5 percent to +5.1 percent). Drug-related serious adverse events were rare in both groups (F/TAF-based regimens, 0.0 percent; F/TDF-based regimens, 0.3 percent); drug discontinuation due to adverse events also was low across both groups (F/TAF-based regimens, 2.1 percent; F/TDF-based regimens, 0.9 percent). The most commonly reported adverse events in both arms included upper respiratory tract infection, diarrhea, nasopharyngitis, headache and bronchitis.

Statistically significant differences were observed in mean changes from baseline to Week 48 in bone mineral density (BMD) between patients receiving F/TAF-based regimens compared to patients receiving F/TDF-based regimens (hip: F/TAF-based regimens, +1.14 percent; F/TDF-based regimens, -0.15 percent; spine: F/TAF-based regimens, +1.53 percent; F/TDF-based regimens, -0.21 percent, p<0.001 for both). Additionally, more patients receiving F/TAF-based regimens experienced a greater than three percent improvement in BMD from baseline to Week 48, compared with those receiving F/TDF-based regimens (hip: F/TAF, 17 percent; F/TDF, 9 percent, p=0.003; spine: F/TAF, 30 percent; F/TDF, 14 percent, p< 0.001).

Statistically significant differences also were observed in multiple tests of renal function between patients receiving F/TAF-based regimens compared to patients receiving F/TDF-based regimens, which included median changes from baseline to Week 48 in estimated GFR (+8.4 mL/min vs. +2.8 mL/min, p<0.001) and median percent changes in: urine protein-to-creatinine ratio (UPCR) (-14.6 percent vs. +7.7 percent; p<0.001); urine albumin-to-creatinine ratio (UACR) (-7.7 percent vs. +12.3 percent; p<0.001); urine retinol binding protein-to-creatinine ratio (-16.3 percent vs. +18.2 percent; p<0.001) and urine beta-2 microglobulin-to-creatinine ratio (-39.6 percent vs. +22.0 percent; p<0.001). There were no cases of proximal renal tubulopathy in either arm.

“The data presented at CROI this week further support the efficacy, safety and tolerability advantages of TAF for a range of patients who face a lifetime of treatment,” said Norbert Bischofberger, PhD, Executive Vice President, Research and Development and Chief Scientific Officer, Gilead Sciences. “If approved, we look forward to offering F/TAF as part of the full portfolio of TAF-based products, which have the potential to represent the next generation of safe, simple and highly effective regimens.”

In April 2015, Gilead filed a New Drug Application (NDA) with the U.S. Food and Drug Administration (FDA) for two fixed-dose combinations of F/TAF (200/10 mg and 200/25 mg), and the FDA has set a target review date under the Prescription Drug User Fee Act (PDUFA) of April 7, 2016. A Marketing Authorization Application (MAA) in the European Union (EU) for F/TAF was fully validated on May 28, 2015.

F/TAF is an investigational product and has not been determined to be safe or efficacious.

About Study 1089

Study 1089 is a 96-week randomized, multi-center, double blind, active controlled study of 663 virologically suppressed HIV-1 infected adult patients receiving F/TDF-based regimens. The study was designed to evaluate the efficacy and safety of switching from F/TDF to F/TAF, versus continuing F/TDF while remaining on the same third agent. The primary endpoint was virologic success at Week 48.

The median age of participants was 49 years, and females comprised 15 percent of the study population. Inclusion criteria required an estimated glomerular filtration rate (eGFR) ≥ 50 mL/min, according to the Cockcroft-Gault formula for creatinine clearance. The median estimated eGFR at study initiation was 100 mL/min. Approximately 46 percent of patients enrolled were treated with a boosted protease inhibitor, 28 percent were treated with an integrase inhibitor and 25 percent were treated with a non-nucleoside reverse transcriptase inhibitor (NNRTI). Additional information about the study can be found at www.clinicaltrials.gov.

About Gilead Sciences

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases. Gilead has operations in more than 30 countries worldwide, with headquarters in Foster City, California.

Forward-Looking Statement

This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including the possibility that the FDA and other regulatory authorities may not approve F/TAF and other F/TAF-based regimens in the currently anticipated timelines or at all, and marketing approvals, if granted, may have significant limitations on their use. As a result, F/TAF and other F/TAF-based regimens may never be successfully commercialized. Further, there is a possibility of unfavorable results from other clinical trials involving F/TAF-based regimens. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in Gilead’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2015, as filed with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements.

U.S. full prescribing information for Truvada and Viread, including BOXED WARNING, is available at www.gilead.com .

Truvada and Viread are registered trademarks of Gilead Sciences, Inc.

For more information on Gilead Sciences, please visit the company’s website at www.gilead.com , follow Gilead on Twitter ( @GileadSciences ) or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.

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