Vicuron Pharmaceuticals Inc.'s stock soared 21.9 percent Thursday after the firm said it would seek regulatory approval later this year on favorable data from a Phase III program of once-weekly dalbavancin in skin and soft-tissue infections caused by Gram-positive bacteria.
The stock (NASDAQ:MICU) jumped $2.27 Thursday to close at $12.63.
In a conference call with reporters, investors and analysts, company officials said the consistent response vs. the standard of care observed with dalbavancin across all three clinical trials was encouraging.
The program involved 1,500 patients who were randomized to one of three trials measuring dalbavancin against linezolid, cefazolin or vancomycin, the three most widely administered standard-of-care agents for skin and soft-tissue infections (SSTIs), George Horner, Vicuron's president and CEO, said during the conference call.
Dalbavancin was dosed once a week for two weeks, while linezolid, cefazolin and vancomycin were dosed 28 or more times over 14 days, said Dov Goldstein, Vicuron's chief financial officer, adding that infrequent dosing is the key difference between dalbavancin, an intravenous antibiotic, and the other products.
Each of the trials met the primary endpoint of non-inferiority at two weeks following therapy vs. the standard of care.
Dalbavancin is a next-generation glycopeptide agent that belongs to the same class as vancomycin, the most widely used and one of the few treatments available to patients infected with the most difficult-to-treat strains of Staphylococcus: methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. epidermidis (MRSE).
The majority of patients treated in the Phase III program had SSTIs caused by S. aureus bacteria, with more than 400 patients infected with MRSA. According to the company, SSTIs are some of the most common infections seen in the clinic and hospital. Post-operative surgical-site infections are one of the major sources of the infections.
Goldstein told BioWorld Today the incidence of hospital-based and community-based MRSA infections has increased over the last decade or so. "We actively tried to keep MRSA out of our uncomplicated skin study because the comparator doesn't work against those bugs, and we still ended up with 20 percent MRSA," he said.
Indeed, the uncomplicated SSTI study was a controlled, double-blind trial of 565 patients vs. intravenous cefazolin followed by oral cephalexin. The primary endpoint was clinical response at the follow-up visit. Evaluable patients taking dalbavancin demonstrated an 89.1 percent response vs. 89.1 percent for cefazolin (95 percent confidence interval -6.8, 6.8).
In the intent-to-treat (ITT) group, dalbavancin patients showed a 76 percent response vs. a 75.8 percent response for cefazolin (95 percent confidence interval -7.7, 8.2).
The complicated SSTI study was a controlled, double-blind trial of 854 patients vs. linezolid. Like the uncomplicated study, the primary endpoint was clinical response at the follow-up visit. Evaluable patients taking dalbavancin demonstrated an 88.9 percent response vs. 91.2 percent for linezolid patients (95 percent confidence interval -7.3, 2.9).
In the ITT group, dalbavancin patients showed a 76.5 percent response vs. 82.7 for linezolid (95 percent confidence interval -12.0, -0.3).
Finally, the trial in SSTIs caused by MRSA was a controlled, open-label study of 156 patients vs. vancomycin. (The study was not pivotal, but will be part of the NDA submission.) The primary endpoint was clinical response at the follow-up visit. Evaluable patients taking dalbavancin demonstrated an 89.9 percent response vs. 86.7 percent for vancomycin (95 percent confidence interval -13.0, 19.4).
In the ITT group, dalbavancin patients showed an 86 percent response vs. 65.3 percent for vancomycin (95 percent confidence interval 4.3, 37.0).
The company said dalbavancin was well tolerated in each of the three studies.
Dalbavancin was discovered by Biosearch Italia SpA, a Milan, Italy-based firm that merged with Versicor Inc., of Fremont, Calif., to form Vicuron. The transaction was completed in 2002, and valued at $225 million. (See BioWorld Today, Aug. 1. 2002.)
Vicuron owns worldwide rights to dalbavancin, and plans to market it on its own in the U.S. Company officials have not determined when they will file for approval in other areas of the world. They will seek priority review in the U.S.
Beyond dalbavancin, Vicuron continues working to get anidulafungin to market. In May, the FDA issued an approvable letter saying the new drug application did not support approval in esophageal candidiasis. The company's stock was crushed on the news, dropping $8.86, or 40.5 percent, to close at $13.04 that day.
The FDA said it might approve anidulafungin in invasive candidiasis/candidemia if the Phase III trial now under way provided positive results. That trial is expected to be complete by the end of 2004. (See BioWorld Today, May 25, 2004.)
Goldstein said he expects to have an update on the anidulafungin situation in September.