News Feature | June 10, 2014

Cubist Reports Positive Phase 3 Data For Antibiotic Sivextro

By Estel Grace Masangkay


Cubist Pharmaceuticals announced positive data from its pivotal Phase III trial evaluating its investigational antibiotic Sivextro (tedizolid phosphate) for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and complicated skin and soft tissue infections (cSSTI).

Sivextro is a novel oxazolidinone antibiotic drug candidate being developed for the potential treatment of ABSSSI and cSSTI as an oral and I.V. administrated treatment. The drug is also being investigated as treatment for nosocomial pneumonia (hospital-acquired bacterial pneumonia [HABP] and ventilator-associated bacterial pneumonia [VABP]).

ABSSSI and cSSTI involve deeper tissue and may require surgical intervention. Gram-positive pathogens Staphylococcus aureus and Streptococcus pyogenes are the two most common bacteria that cause the soft tissue infections. Growing incidence of methicillin-resistant strains of the bacteria has resulted in a medical need for effective therapeutics for MRSA.

Gregory J. Moran, Clinical Professor at the UCLA Department of Emergency Medicine, said, “With limitations of some existing therapies, including resistance to certain agents, there is a need for new antibiotics in addition to a focus on appropriate use. It is encouraging to see these clinical trial data in hospital and outpatient settings, as SIVEXTRO may become a potential treatment option for acute bacterial skin and skin structure infections, including those caused by MRSA.”

Results from the ESTABLISH-2 study showed that a six-day course of once-daily Sivextro was on par with 10 days treatment of twice-daily linezolid for ABSSSI. The trial met both its primary and secondary endpoints set by the FDA and the EMA.

The results of the trial were published at the Lancet Infectious Diseases and set to appear in a future print edition of the journal. Steven Gilman, EVP of Research and Development and CSO of Cubist Pharmaceuticals, said, “Publication of ESTABLISH-2 clinical trial results in The Lancet Infectious Diseases contributes important information to the infectious disease community worldwide about Sivextro. These data provide further support for the potential of Sivextro as a novel treatment option that might be used in the transition from I.V. to oral therapy in a short, six-day course of treatment for patients with serious skin infections.”

Regulatory applications are undergoing review both in the U.S. and in the EU. The FDA has accepted the company’s NDA for Sivextro under Priority Review, with its FDA Anti-Infective Drug Advisory Committee (AIDAC) recommending approval in March 2014.  The European Medicines Agency has also accepted for review Cubist’s Marketing Authorization Application for the drug.