Advancis Pharmaceutical Corporation and Par Pharmaceutical Companies, Inc. announced that the companies' Amoxicillin Pulsys phase III clinical trial for the treatment of adults and adolescents with pharyngitis/tonsillitis due to Group A streptococcal infections (commonly referred to as strep throat) failed to achieve its desired microbiological and clinical endpoints.

The trial compared Advancis' Amoxicillin Pulsys 775 milligram tablet dosed once-daily for seven days to 250 milligrams of penicillin VK dosed four times daily for 10 days. According to top-line trial data received, Amoxicillin Pulsys failed to demonstrate statistical non-inferiority to the comparator therapy in the primary endpoint - bacterial eradication at the post-therapy test-of-cure visit for patients who successfully completed the trial protocol.

Success in bacterial eradication at the post-therapy test-of-cure visit in the per-protocol population was 76.6 per cent (131/171) of patients with Amoxicillin Pulsys and 88.5 per cent (161/182) with penicillin. These results failed to demonstrate statistical non-inferiority (95 per cent confidence interval of -20.0; -4.4). Amoxicillin Pulsys also failed to demonstrate non-inferiority in the trial's secondary endpoints, including clinical cure at the test-of-cure visit and bacterial eradication at the late post-therapy visit. Advancis will review the full data over the coming weeks and evaluate what steps, if any, could be taken to improve future outcomes.

"We are disappointed in the trial results for our adult Amoxicillin Pulsys product. We will further investigate these results and look to the results of our paediatric phase III trial that we anticipate receiving next month before deciding upon the next steps for our amoxicillin program," said Dr Edward Rudnic, Advancis chairman and chief executive officer.

Whether or not the paediatric study achieves its primary and secondary endpoints, the company anticipates that it would be required to establish efficacy in a new phase III adult and adolescent trial before it could file a New Drug Application (NDA) for its Amoxicillin Pulsys products. As a result, the company believes that a potential NDA filing, if any, for such products will be delayed by at least one year.