Cubist bounces along with more promising PhIII antibiotic results

Cubist Pharmaceuticals' ($CBST) in-development antibiotic aced the second leg of its Phase III program, the company said, paving the way for an FDA application and bumping its shares up another 9%.

In top-line results revealed this morning, Cubist's ceftolozane/tazobactam met its primary endpoint in complicated intra-abdominal infections, charting a clinical cure rate 26 to 30 days after initiation that was noninferior to standard meropenem, according to the company. The rates of side effects were roughly the same for Cubist's drug and the old standard, and the most common adverse reactions were nausea, diarrhea and fever, Cubist said.

These latest results come on the heels of a Phase III study unveiled last month in which ceftolozane/tazobactam proved itself statistically noninferior to levofloxacin in complicated urinary tract infections. And while Cubist is keeping the full data under wraps for now, the company believes it has the results necessary to get its antibiotic approved by the FDA and EMA. Cubist plans to submit an NDA for both indications in the first half of next year and make a pitch to European regulators in H2.

"These data are encouraging as we face alarmingly increasing rates of bacterial resistance," Weill Cornell Medical College professor and Cubist investigator Philip Barie said in a statement. "There is an urgent need for new antibiotics, especially in the hospital setting, in order to be able to manage effectively those conditions complicated by serious infections, including those caused by resistant Gram-negative bacteria."

The intra-abdominal data boosted Cubist's shares nearly 9% to $69.27 on Monday morning, a reverberation of the 10% leap the company took after posting urinary tract results on Nov. 25. Cubist has risen roughly 53% since the start of the year.

Cubist has high hopes for the combination antibiotic, paying $402 million in 2009 for Calixa to get its hands on the treatment and this year buying out partner Astellas for $25 million to acquire sole rights to the drug's future.

The Lexington, MA, company also has its eye on a hospital-acquired bacterial pneumonia indication for ceftolozane/tazobactam, planning to launch an attendant Phase III trial in the first half of next year. The FDA has added Cubist's drug to its fast-track program thanks to its promise in infectious disease.

- read the announcement

Editor's note: An earlier version of this story misidentified one of ceftolozane/tazobactam's endpoints. We regret the error.