The FDA approved Cubist Pharmaceuticals Inc.'s first-in-class antibiotic, Cubicin, for infections caused by Gram-positive bacteria.
Cubicin (daptomycin for injection, formerly known as Cidecin) is cleared for use in hospitals to fight complicated skin and skin-structure infections, including those caused by MRSA (methicillin-resistant Staphylococcus aureus) and MSSA (methicillin-susceptible S. aureus). It's also indicated for treating strains of the following Gram-positive microorganisms: Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subspecies equisimilis and Enterococcus faecalis (vancomycin-susceptible strains only).
An FDA press statement described Cubicin as a cyclic lipopeptide antibacterial agent that treats infections in a way that is distinct from any other antibiotic.
Indeed, Scott Rocklage, Cubist's chairman, told BioWorld Today new classes of antibiotics are particularly important because bacteria have developed resistance to many current classes of drugs. "So by having a new class with a killing mechanism of action gives Cubicin an advantage over currently marketed classes."
As to Cubicin's resistance potential, Rocklage said, "The expectation, biologically, is that it will take some period of time, but no one really can predict it. In clinical studies, what we have found is an incredibly low frequency of resistance, much lower than what has been seen before, and that's consistent with its bactericidal nature. The expectation from the antibiotic community is that this drug will not develop resistance rapidly."
Jason Kantor, managing director with W.R. Hambrecht + Co. in San Francisco, told BioWorld Today that Cubicin will be used for serious infections, such as surgical or wound infections, that are potentially life threatening or limb damaging. At peak, the U.S. market for Cubicin should reach $300 million, said Kantor, adding that the estimate is probably conservative.
Cubist, of Lexington, Mass., intends to launch and market the product in November on its own, with 75 salespeople.
As for Europe, Rocklage said Cubist expects to file for regulatory approval in 2004 and will seek a partner.
Cubist and its former European partner, Gilead Sciences Inc., of Foster City, Calif., mutually terminated their agreement almost a year ago. That happened a couple of months before Gilead disclosed its plan to merge with Triangle Pharmaceuticals Inc., of Durham, N.C. When asked about the situation on Monday, Rocklage said Cubicin did not fit into Gilead's antiviral therapy focus. Initially signed in 2001, the deal between the two included a $13 million up-front payment to Cubist. (See BioWorld Today, Sept. 11, 2002; Dec. 5, 2002; and Jan. 9, 2001.)
Cubist acquired rights to Cubicin back in 1997 from Indianapolis-based Eli Lilly and Co. In late July, Cubist issued $8 million worth of common stock to Lilly after completing a transaction through which Cubist purchased a 1 percent reduction in the royalties payable to Lilly on net sales of Cubicin.
The company filed its new drug application in December, and was awarded priority review status, meaning the FDA was bound to an action date, or Prescription Drug User Fee Act date, sometime in June. When the time came for action, the FDA informed the company that it needed three extra months to go over the company's response to a question concerning reformatting of data and to reschedule label discussions.
Nevertheless, the NDA was approved based on safety data from 1,409 study participants, data on the in vitro activity spectrum of Cubicin against about 21,000 global clinical bacterial isolates, and efficacy data from two pivotal Phase III studies in complicated skin and skin-structure (cSSS) infections, the company said. (See BioWorld Today, Oct. 5, 2001, and March 15, 2001.)
In the studies, Cubicin met the prospective endpoint of demonstrating equivalency to the gold standard treatment (either vancomycin or a semi-synthetic penicillin such as oxacillin or nafcillin) in the treatment of cSSS infections. According to the company, the clinical success rate for Cubicin was 83.4 percent, and 84.2 percent for the comparator.
Cubist's stock fell 46 percent to close at $17.02 in January 2002 when Cubicin failed in a Phase III trial against community-acquired pneumonia. (See BioWorld Today, Jan. 18, 2002.)
Cubicin is the subject of a Phase III trial in infective endocarditis and bacteremia.
Cubist's stock (NASDAQ:CBST) closed Monday at $12.64, down 70 cents.