LEDERLE’s ZOSYN WILL BE LAUNCHED IN NOVEMBER

LEDERLE's ZOSYN WILL BE LAUNCHED IN NOVEMBER and will be competitively priced to SmithKline Beecham's Timentin (ticarcillin/clavulanate) and "priced significantly less than" Merck's Primaxin I.V. (imipenem/cilastatin), competitors in the I.V. antibiotic market, the company said Oct. 25. Zosyn, a combination of the previously approved broad spectrum antibiotic piperacillin sodium and the beta-lactamase inhibitor tazobactam sodium, was approved Oct. 22 ("The Pink Sheet" Oct. 25, In Brief). Lederle's NDA (50-684) was submitted Aug. 30, 1991. "Zosyn is indicated as presumptive therapy before the specific cause of an infection has been identified, and for the treatment of mixed (polymicrobial) infections caused by microorganisms that produce beta-lactamases, enzymes which enable certain bacteria to resist many antibiotics," Lederle said Oct. 25. The combination is specifically indicated for treating piperacillin resistant infections of four types: appendicitis (complicated by rupture or abscess) and peritonitis; uncomplicated and complicated skin and skin structure infections, including cellulitis, cutaneous abscesses, and ischemic/diabetic foot infections; postpartum endometritis or pelvic inflammatory disease; and community-acquired pneumonia (moderate severity only). Labeling adds that "clinical trial data for the treatment of complicated urinary tract infections demonstrated inadequate efficacy at the dosage regimen of Zosyn studied." Timentin and Primaxin I.V. labeling carry more indications than Zosyn and those indications are more general in scope than the ones approved for Zosyn. According to recent studies, Zosyn is "more effective than the current standard therapies for potentially life-threatening lower respiratory tract and intra-abdominal infections," Lederle maintained. In one study, "Zosyn cured or improved 84% of patients with community-acquired lower respiratory tract infections, compared to 64% for SmithKline Beecham's Timentin," the company said. In a second Phase III trial, "Zosyn cured or improved 88% of patients with serious intra-abdominal infections, compared to 77% for combination therapy of clindamycin phosphate plus gentamicin," Lederle added. Both studies were submitted to FDA as part of the NDA package. "During the clinical investigations, 2,621 patients worldwide were treated with Zosyn in Phase III trials," labeling states. In North American trials, 3.2% of 830 patients discontinued due to side effects involving skin (1.3%, rash and pruritis), the gastrointestinal system (.9%, diarrhea, nausea and vomiting) and allergic reactions (.5%). The "usual total daily dose of Zosyn" is 3.375 g (3 g piperacillin/.375 g tazobactam) every six hours, administered by 30-minute infusion, labeling states. The drug is supplied in single-dose vials of 2.25 g, 3.375 g, and 4.5 g. FDA's approval letter states that Lederle has agreed to two Phase IV studies: "A study of the disposition of the piperacillin- aminoglycoside and piperacillin/tazobactam-aminoglycoside complexes"; and "a study to determine whether tazobactam causes nonspecific binding of IgG and albumin by red cell membranes which could lead to a false-positive Coombs' test." Zosyn is licensed by Lederle from Taiho Pharmaceuticals. Under a cross-marketing agreement announced in July, Medimmune will copromote Zosyn with Lederle ("The Pink Sheet" July 19, T&G-11). Lederle said its approximately 1,000 sales reps have undergone an intensive training program to prepare for the hospital market.