Actavis plc, a unique, global pharmaceutical company, announced positive top-line results for study DUR001-303, a phase 3 study comparing a single 1500 mg dose of Dalvance with the same total dose given as two-doses one week apart, for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by susceptible gram-positive bacteria, including methicillin resistant Staphylococcus aureus (MRSA).

Preliminary top-line data demonstrated the 1500 mg single-dose of Dalvance achieved its primary endpoint of non-inferiority to the two-dose regimen (10% non-inferiority margin) at 48-72 hours after initiation of therapy, as determined by a decrease of > 20 per cent in lesion area relative to the baseline measurement  (81.4 per cent vs 84.2 per cent for the single dose vs.the two dose regimen, respectively; Difference -2.9; 95 per cent CI: -8.5, 2.8). Similar proportions of patients with Staphylococcus aureus infections at baseline were clinical responders at the 48-72 hour time-point within each treatment group (122/137 (89.1 per cent) in the single-dose treatment group and 124/145 (85.5 per cent) in the two-dose treatment group).

"We are pleased with the results demonstrated in this trial. Single-dose Dalbavancin has shown positive results for the treatment of serious skin infections and can be an important new treatment option for patients," said David Nicholson, Actavis executive vice president, Global Brands R&D.

In addition, the trial assessed the secondary outcome measures of clinical response at day 14 (the EMA primary endpoint) as well as at day 28. The single-dose of Dalvance provided similar treatment efficacy to the two dose regimen in these secondary endpoints. 94.4 per cent of patients in the single-dose Dalvance arm and 94.0 per cent of patients in the two-dose Dalvance arm achieved clinical success at day 14 (95 per cent CI -3.5, 4.3). At day 28, 84.5 per cent of patients treated with a single-dose of Dalvance achieved clinical success compared to 85.1 per cent of those treated with the two-dose regimen of Dalvance (95 per cent CI -6.0, 4.8).

Dalvance is the first and only IV antibiotic approved for the treatment of ABSSSI with a two-dose regimen of 1000 mg followed one week later by 500 mg, each administered over 30 minutes.

Actavis plans to file a supplemental New Drug Application (sNDA) with these data in Q3 2015.

DUR001-303 study was conducted pursuant to a special protocol agreement (SPA) with the US Food and Drug Administration (FDA) based on the FDA's guidance for developing drugs for treatment of ABSSSI.

DUR001-303 was a randomized, double-blind, double-dummy trial conducted in 698 patients at 62 sites in the United States, Europe and South Africa comparing a single 1500 mg intravenous (IV) dose of Dalvance to the approved regimen of two-doses given one week apart (1000 mg IV on day 1followed by 500 mg IV on day 8).

The treatment-emergent adverse event rate for single dose Dalbavancin was 22.3 per cent compared to 21.1 per cent for the two-dose regimen. The most commonly reported adverse events with an incidence >1 per cent for the single dose of dalbavancin were nausea, headache, vomiting, diarrhea, and dizziness, similar in frequency to the two-dose regimen.

Discontinuations due to treatment emergent adverse events were 1.7 per cent and 1.4 per cent for the single and two-dose regimens, respectively.