Positive Phase III results with Paratek's omadacycline

USA-based Paratek Pharmaceuticals (Nasdaq: PRTK) has announced that the Phase III registration study comparing its once-daily, broad spectrum antibiotic, omadacycline, to linezolid (Zyvox, from Pfizer) in the treatment of acute bacterial skin and skin structure infections (ABSSSI) met the US Food and Drug Administration-specified primary efficacy endpoint of early clinical response.

In addition, the study met the two European Medicines Agency-specified co-primary efficacy endpoints for post-treatment evaluation. This positive study is the first of two Phase III registration studies designed to support omadacycline regulatory applications for the FDA and EMA. Shares of Paratek climbed 23.5% to $20.30 in robust after-hours trading on Wednesday.

If omadacycline succeeds in gaining regulatory approval, it will have done so despite three different partners – Bayer, Merck and Novartis – each pulling out of collaborations on the drug for different reasons.