Shares of Advancis Pharmaceutical Corp. shot up 46 percent on news that its once-daily Amoxicillin Pulsys product finally met its endpoint in a Phase III trial in strep throat patients.

After failing to demonstrate adequate bacterial eradication and non-inferiority to penicillin in two separate Phase III studies last summer - one in adults and adolescents and one in a pediatric population - the company decided to attempt once more to prove the efficacy of its once-daily, 775-mg pulsatile-release formulation of amoxicillin. The only change was an increase in the treatment period from seven days to 10 days in adult and teenage patients with tonsillitis/pharyngitis due to Group A streptococcal infections.

As with the previous studies, Amoxicillin Pulsys was compared to 250 mg of penicillin VK dosed four times daily.

Top-line data from the 620-patient trial demonstrated statistical noninferiority to the comparator arm, as well as an 85 percent bacterial eradication at patients' post-therapy test-of-cure visit vs. 83.4 percent in the penicillin arm.

Advancis said the FDA requires a minimum of 85 percent eradication for marketing approval. In earlier studies, with the seven-day treatment regimen, overall bacterial eradication was 77 percent in the adult and adolescent population and 68 percent for the pediatric patients. (See BioWorld Today, June 17, 2005, and July 25, 2005.)

The Germantown, Md.-based firm expects to have full results by the end of September, and anticipates a new drug application filing late this year or early next year.

Amoxicillin is indicated for a range of infections, but is not approved for a once-daily dosing in pharyngitis. Advancis has said it believes it could capture a significant portion of the annual $600 million market with a product that calls for less frequent administration, and therefore, yields higher patient compliance.

Advancis' stock (NASDAQ:AVNC) gained $1.45 Thursday to close at $4.57, the highest its shares have closed since last summer.

It hasn't been an easy ride for the company since its lead product failed in Phase III trials last year. Determined to conduct another trial, Advancis began streamlining its resources and cut 33 jobs, including six executive positions. (See BioWorld Today, Aug. 1, 2005.)

The need for capital became even more critical when Spring Valley, N.Y.-based Par Pharmaceutical Corp., Advancis' partner responsible for funding the late-stage trials of Amoxicillin Pulsys, pulled out of the deal. The company then had hoped to bring in $12 million through the sale of its U.S. Keflex rights - the pain product was acquired from Indianapolis-based Eli Lilly and Co. the year before - to an undisclosed private firm, but that deal fell through, too. (See BioWorld Today, Aug. 6, 2005, and Sept. 16, 2005.)

Advancis reported a net loss of $10.7 million, or 35 cents per share, for the second quarter. As of June 30, the company had a cash position of $20.9 million, though it added an additional $12 million last month in a senior secured credit facility.