New Ph III data support early 2014 filing for Cubist’s ceftolozane/tazobactam

US drugmaker Cubist Pharmaceuticals (Nasdaq: CBST) saw its shares jump 8.3% to $68 in premarket trading yesterday, when the company released positive top-line results from the pivotal Phase III clinical trial of its antibiotic candidate ceftolozane/tazobactam (also referred to as tol/taz and CXA-201) in complicated intra-abdominal infections (cIAI).

Ceftolozane/tazobactam, in combination with metronidazole, met the US Food and Drug Administration and the European Medicines Agency defined primary endpoints of statistical non-inferiority compared to meropenem (AstraZeneca’s Monan or Meronem). The primary endpoint was a clinical cure rate 26-30 days after the initiation of therapy (the Test of Cure visit).

For the FDA, the primary analysis was conducted in the Microbiological Intent-to-Treat (MITT) population; the non-inferiority margin was 10%; and the lower and upper bounds of the 95% confidence interval were -8.9% and 0.5%, respectively. For the EMA, the primary analysis population was Clinically Evaluable (CE) patients; the non-inferiority margin was 12.5%; and the lower and upper bounds of the 99% confidence interval were -4.2% and 4.3%, respectively. Results of the secondary analysis were consistent with and supportive of the primary outcome.