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Gilead Provides More Sofosbuvir Data, Plans for Further Hepatitis C Studies

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Gilead Sciences this week provided updated results from the ELECTRON trial evaluating sofosbuvir, GS-5885, and ribavirin, coinciding with a presentation at a financial conference in San Francisco. The company also provided information about studies of its sofosbuvir/GS-5885 combination pill now in development.

At the recent AASLD Liver Meeting ELECTRON researchers reported that most people treated with sofosbuvir (an HCV polymerase inhibitor) plus ribavirin relapsed after the end of treatment, but those who added the HCV NS5A inhibitor GS-5885 had sustained viral suppression at 4 weeks post-treatment (see link for history of ELECTRON trial and recently published results).

That report included 3 of 9 null responders to prior interferon-based therapy who had reached the 4-week post-treatment endpoint.

This week the company reported further follow-up data showing that all 9 prior null responders -- the most difficult group to treat -- who received a 12-week triple regimen of sofosbuvir/GS-5885/ribavirin had sustained virological response at 4 weeks post-treatment (SVR4). SVR at post-treatment week 12 is widely regarded as a cure.

Gilead is now testing a sofosbuvir/GS-5855 coformulation, with and without ribavirin, and for durations as short as 8 weeks. Sofosbuvir has already demonstrated excellent outcomes in a dual regimen with another NS5A inhibitor, Bristol-Myers Squibb's daclatasvir, though Gilead has declined to pursue further studies of that combination.

Below is an edited excerpt from a Gilead press release describing the latest data and forthcoming trials.

Gilead Provides Update on Hepatitis C Development Programs

  • Sustained Virologic Response Achieved with Oral Regimen of Sofosbuvir, GS-5885 and Ribavirin in 9/9 Null Responder Genotype 1 Hepatitis C Patients
  • Second Phase 3 Study Evaluating Fixed-dose Combination of Sofosbuvir and GS-5885 to Begin Later this Month

Foster City, Calif. -- January 7, 2013 -- Gilead Sciences (Nasdaq:GILD) today announced several updates regarding its late-stage pipeline candidates for the treatment of chronic hepatitis C virus (HCV) infection. The company released new results from an arm of the ongoing Phase 2 ELECTRON study examining the nucleotide sofosbuvir and the NS5A inhibitor GS-5885, and provided a progress report on a range of Phase 2 and 3 clinical trials evaluating a once-daily fixed-dose combination tablet of these medicines. These updates will be highlighted today as part of Gilead’s corporate presentation at the 31st Annual J.P. Morgan Healthcare Conference taking place in San Francisco.

"Since the acquisition of Pharmasset only a year ago, we have fully enrolled four Phase 3 studies of sofosbuvir and during the first quarter of this year we will have initiated two Phase 3 studies of the sofosbuvir and GS-5885 fixed-dose combination," said Norbert Bischofberger, PhD, Executive Vice President, Research and Development and Chief Scientific Officer, Gilead Sciences. "We are on track to submit the initial regulatory filing for sofosbuvir by mid-2013 and to file for approval of the fixed-dose combination of sofosbuvir and GS-5885 in 2014."

Update on Phase 2 ELECTRON Study

Gilead today announced full data from one cohort of the ongoing Phase 2 ELECTRON study examining a 12-week course of all-oral therapy with sofosbuvir, GS-5885 and ribavirin (RBV) among genotype 1 HCV patients who had previously failed to respond to an interferon (IFN)-containing regimen, or “null responders.”

Preliminary data, presented in November at the annual meeting of the American Association for the Study of Liver Diseases (AASLD), demonstrated that three of nine patients (3/9) remained HCV RNA undetectable four weeks after completing therapy (SVR4). Today’s announcement confirms that all nine patients (9/9) in this cohort achieved SVR4. These patients will continue to be observed to determine sustained virologic response rates at weeks 12 and 24 of follow-up (SVR12 and SVR24).

Results from eight other arms of the ELECTRON study, evaluating sofosbuvir alone and with RBV and/or pegylated IFN, were published earlier this month in the New England Journal of Medicine (N Engl J Med 368;34-44).

Advancing a Fixed-Dose Combination Tablet for HCV

Gilead is currently evaluating a once-daily fixed-dose combination tablet containing sofosbuvir and GS-5885 in several Phase 2 and 3 trials. The studies evaluate sofosbuvir/GS-5885 with and without RBV among a range of genotype 1 HCV patient populations.

  • ION-1: This Phase 3 trial was initiated in October 2012 and is evaluating sofosbuvir/GS-5885 with and without RBV for 12 or 24 weeks among treatment-naive genotype 1 patients. Pending a review of results from the two 12-week arms (n=50/arm) of an initial enrollment of 200 patients, ION-1 will continue to recruit patients and assess sofosbuvir/GS-5885 in a total of 800 individuals.
  • ION-2: Gilead today announced that a second Phase 3 study for sofosbuvir/GS-5885, ION-2, is expected to begin screening patients in January 2013. This study will evaluate the fixed-dose combination, with RBV for 12 weeks and with and without RBV for 24 weeks of therapy among 400 treatment-experienced genotype 1 HCV patients. Participants in this study will have failed past therapy with regimens containing IFN or IFN plus a protease inhibitor.
  • LONESTAR: Gilead also announced that enrollment is now underway for a new Phase 2 study of sofosbuvir/GS-5885 for 12 weeks and of sofosbuvir/GS-5885 with and without RBV for 8 weeks among genotype 1 treatment-naïve patients. Two additional arms in this trial will evaluate sofosbuvir/GS-5885 with and without RBV for 12 weeks among treatment-experienced genotype 1 patients who had previously received a protease inhibitor-containing regimen. This study, which will enroll 100 patients, is the first trial to evaluate the combination of sofosbuvir and GS-5885 for only eight weeks of treatment.

Sofosbuvir, GS-5885 and the fixed-dose combination tablet are investigational products and their safety and efficacy have not yet been established.

Four ongoing Phase 3 studies will support Gilead’s initial regulatory filing in mid-2013 for an all-oral therapy with sofosbuvir plus RBV among genotype 2/3 treatment-naive, treatment-experienced and interferon-intolerant patients, and for sofosbuvir in combination with RBV and peg-IFN among treatment-naive patients with HCV genotypes 1, 4, 5 and 6. Topline results from the first Phase 3 study, POSITRON, were announced in November 2012, and results from the remaining three studies (FISSION, FUSION and NEUTRINO) are anticipated in Q1 2013. Results from ION-1, ION-2 and LONESTAR are intended to support a regulatory filing for the fixed-dose combination of sofosbuvir/GS-5885 by mid-2014.

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 worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Asia Pacific. 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.

12/8/13

Source

Gilead Science. Gilead Provides Update on Hepatitis C Development Programs. Press release. January 7, 2013.