The FDA approved Cubist Pharmaceuticals’ antibiotic Sivextro, the second drug approved for acute bacterial skin and skin structure infections as part of the agency’s effort to encourage the development of new antibiotics as a bulwark against growing drug resistance.

On May 23, the agency also approved Durata Therapeutics’ Dalvance (dalbavancin) for the same indication.

Sivextro (tedizolid phosphate) was approved under the qualified infectious disease products (QIDP) designation, created in 2012 to spur development of drugs for increasingly resistant pathogens. QIDP status grants a priority review, fast-track approval and five extra years of post-approval exclusivity under the Hatch-Waxman Act.

Cubist, which acquired Sivextro in its purchase of Trius Therapeutics last July, said it plans to invest $400 million and devote 75 percent of its employees in 2014 to R&D, commercialization and support of antimicrobial drugs. The firm hopes to produce at least four antibiotics between now and 2020, said spokeswoman Kim McCrossen.

The company currently has a combination drug of ceftolozane and tazobactam awaiting FDA approval by Dec. 21 for complicated urinary tract infections and complicated intra-abdominal infections. Cubist also is waiting on European Medicines Agency marketing authorization for Sivextro.

Even with the new approvals, “the pipeline for antibiotics is relatively dry,” Pew Director of Drug Safety and Innovation Elizabeth Jungman said. Pew had identified roughly 45 new antibiotics in development as of February, but only about nine of those are statistically likely to make it to market, and this will not be sufficient to meet future needs, she said.  

To further speed antibiotics to market, Pew and other groups have proposed a new pathway called Limited Population Antibacterial Drug (LPAD), which would allow the FDA to approve new antibiotics based on clinical trials with limited populations in cases of life-threatening and unmet medical needs. Under this model, companies attempting to market a drug that treats Staphylococcus aureus, for example, would be able to submit Phase II clinical data from the MRSA-specific patient population rather than data from larger Phase III trials incorporating patients with multiple strains of the bacterium.

The LPAD pathway was included in the Antibiotic Development to Advance Patient Treatment Act of 2013, which is now before the House Energy and Commerce Committee. — Lena Freund

Originally appeared in Drug Industry Daily, the pharmaceutical industry’s number one source for regulatory news and information. Click here for more information.