Vicuron Pharmaceuticals Inc., one of Pfizer Inc.'s latest pickups, last week submitted a new drug application for anidulafungin to the FDA, right on schedule.
The King of Prussia, Pa.-based company, whose shareholders just voted in favor of the $1.9 billion buyout by Pfizer, is seeking approval for the treatment of invasive candidiasis/candidemia, a common hospital-acquired fungal infection against which the broad-spectrum product has proved effective. Its executives did not return calls seeking comment, but in a press release, Vicuron President and CEO George Horner said the company was "pleased to have filed this NDA in the third quarter as planned."
The application is largely based on Phase III data that demonstrated anidulafungin's superiority over fluconazole in invasive candidiasis/candidemia, exceeding the study's non-inferiority endpoint. In the 256-patient pivotal trial, 75.6 percent of anidulafungin-treated patients had a response compared to 60.2 percent of fluconazole patients. Also, the Vicuron product either matched or bettered results in all secondary endpoints. (See BioWorld Today, Feb. 8, 2005.)
Those data are supported by findings from a range of preclinical studies, including some that have shown that five-minute exposure to anidulafungin in vitro kills more than 99 percent of Candida, including fluconazole-resistant strains. Other in vitro studies have shown that it combines both the potency and killing effects of the polyene class without the resistance problems found in the azole class, to which fluconazole belongs.
Anidulafungin, an echinocandin compound that five years ago was in-licensed from Indianapolis-based Eli Lilly and Co., has not shown cross-resistance with azoles or amphotericin, a polyene drug, and in the laboratory it proved very difficult to develop resistance to anidulafungin.
Anidulafungin is made through chemical modification of a naturally occurring molecule.
The NDA represents the third Vicuron application filed with the FDA - one for dalbavancin, an intravenous antibiotic for serious Gram-positive infections, and two for anidulafungin. The company expects to hear first on dalbavancin, a once-weekly injection for skin and soft-tissue infections, with a regulatory decision due next month. Its NDA was filed late last year. (See BioWorld Today, Dec. 22, 2004.)
Anidulafungin already is the subject of an approvable letter; its original NDA was filed more than two years ago for esophageal candidiasis, followed about a year later by the approvable letter that expressed concerns about a secondary endpoint associated with relapse rate after two weeks of follow-up. Earlier this summer, the company filed an amendment to that NDA to provide supplemental data on the 100-mg dose that were gleaned from the Phase III trial in invasive candidiasis/candidemia, an indication that represents a larger market opportunity than esophageal candidiasis. (See BioWorld Today, April 29, 2003, and May 25, 2004.)
Vicuron owns worldwide rights to both dalbavancin and anidulafungin.
New York-based Pfizer's acquisition is expected to close later this quarter, completing the deal to buy out Vicuron's shares for $29.10 apiece - a 74 percent premium to the stock's 90-day average closing price when the transaction was announced. It remains subject to regulatory approval and other customary closing conditions. (See BioWorld Today, June 17, 2005.)
On Friday, Vicuron's stock (NASDAQ:MICU) gained 6 cents to close at $28.37.