Cubist Wins U.S. FDA Approval for MRSA Antibiotic Sivextro

Jun 20, 2014 6:39 pm ET

June 20 (Bloomberg) -- Cubist Pharmaceuticals Inc. won U.S. approval for its antibiotic Sivextro to treat acute bacterial skin infections, including potentially fatal MRSA.

The Food and Drug Administration cleared Sivextro for use in both intravenous and oral forms, the agency said today in a statement. The drug is the second antibiotic the FDA has approved in a month to treat MRSA, a staph infection often acquired in the hospital that’s resistant to commonly used antibiotics.

The ability of bacteria to mutate and resist treatment is one of the most serious threats to human health, according to the Centers for Disease Control and Prevention. Companies such as Cubist and Durata Therapeutics Inc. are among drugmakers introducing new antibiotics to help combat resistance caused by overuse of older therapies.

“Today’s approval provides physicians and patients with a new treatment option for serious skin infections,” said Edward Cox, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research, in the agency’s statement.

Sivextro, chemically known as tedizolid, benefits from the Generating Antibiotic Incentives Now, or GAIN, Act passed by Congress in 2012 to encourage antibiotic development.

The GAIN Act offers antibiotic drugmakers faster FDA review and five years of additional time to sell their product without generic competition. The incentives helped spur Lexington, Massachusetts-based Cubist’s $707 million acquisition last year of Trius Therapeutics, the developer of Sivextro, Steven Gilman, chief scientific officer at Cubist, said in an interview.

Dalvance Approval

Durata Therapeutics won approval in May for Dalvance to treat acute bacterial skin infections. Furiex Pharmaceuticals Inc., Melinta Therapeutics Inc. and The Medicines Co. are studying antibacterials for the same condition, according to Bloomberg Industries.

Most MRSA, or Methicillin-resistant Staphlyococcus Aureus, infections are skin infections, according to the CDC. Rates of severe MRSA acquired in hospitals are declining, the CDC said.

Cubist makes another MRSA treatment called Cubicin, which also treats bloodstream infections and is given as a daily injection. About one-third of Cubicin’s $900 million in U.S. sales comes from skin infections, Gilman said.

Patients who take Sivextro start using it intravenously and transition to an oral version to make the drug easier to use once patients leave the hospital. A course of Sivextro is given once a day for six days almost half as long as older 10-day treatments that must be taken twice or more a day, Gilman said in an interview. Durata’s Dalvance is given intravenously in two separate doses a week apart.

Cubist is conducting final-phase studies using Sivextro against pneumonia acquired through MRSA infections.