Cubist Shares Climb As Antibiotic Scores in Phase 3 Again

12/16/13Follow @benthefidler

Cubist Pharmaceuticals (NASDAQ: CBST) just got some more promising results to take to regulators next year.

The Lexington, MA-based company said today that CXA-201— the antibiotic it acquired when it bought out Calixa Therapeutics a few years ago—succeeded in the second of two Phase III trials. This time around, the drug proved to be just as effective as generic antibiotic meropenem at treating complicated intra-abdominal infections. With two successful late-stage clinical trials completed, Cubist will submit applications to the FDA and European Medicines Agency in 2014 for clearance to start selling the new antibiotic.

Shares of Cubist climbed around 8 percent in early trading.

In the 993-patient study, Cubist tested whether CXA-201, when injected along with another antibiotic, metronidazole, could get rid of the infection within 26 to 30 days of patients taking the first dose of the drug. The study was designed to see whether Cubist’s drug was just as effective in doing so as meropenem, the standard of care for such infections. Cubist reported that, statistically speaking, it succeeded in its goal, in that CXA-201 demonstrated “non-inferiority.” Cubist only disclosed top-line figures, however. It’ll present the full details at an upcoming medical meeting.

The most common side effects experienced by patients taking the Cubist drug were nausea, diarrhea, fever, insomnia, and vomiting. But Cubist said those side effects were just as prevalent in the patients taking meropenem.

Cubist reported just a few weeks ago that CXA-201 was similarly effective at treating people with complicated urinary tract infections in a separate Phase III study. The results from that study surprised analysts because CXA-201 performed better, statistically speaking, than the drug it was tested against (levofloxacin)—something that trial wasn’t designed to show. Cubist made no such claims this time around, but nonetheless, it now has two studies to point to when it puts its data package together for regulators.

CXA-201 is a combination of two antibacterial compounds, cephalosporin and tazobactam. Cubist added the drug to its portfolio when it bought San Diego, CA-based Calixa for $92.5 million up front and $310 million in milestone payments.

Ben Fidler is Xconomy's Deputy Biotechnology Editor. You can e-mail him at bfidler@xconomy.com Follow @benthefidler

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