Washington Editor

Peninsula Pharmaceuticals Inc. initiated patient enrollment in its fifth pivotal Phase III trial of doripenem for injection, a candidate for patients with hospital-acquired pneumonia.

The safety and efficacy trial will compare doripenem with intravenous piperacillin/tazobactam, the Alameda, Calif.-based firm said. The primary endpoint is clinical response at the test-of-cure visit (seven to 14 days following completion of therapy) in patients with a confirmed bacterial pathogen. Patients will be enrolled at sites around the world.

Doripenem for injection (also referred to as S-4661) is a sterile, synthetic, parenteral carbapenem antibiotic discovered by Shionogi & Co. Ltd., of Osaka, Japan. Carbapenem antibiotics are highly useful due to their potent antibacterial activities with broad antibacterial spectrum and stability against most ß-lactamases. Doripenem is a new member of this carbapenem class, which includes imipenem, meropenem and ertapenem, the company said.

Just a year ago, Peninsula in-licensed doripenem from Shionogi, gaining rights to develop and sublicense it in North America, South America and Europe. (See BioWorld Today, May 28, 2003.)

Officials at Peninsula were unable to comment on the news due to an SEC-imposed quiet period related to a proposed initial public offering filed in December. Originally the company believed it would raise $86.25 million, but had adjusted the amount to $75 million by mid-February, a total that would be achieved by selling 5.75 million shares at $12 to $14 apiece.

Meanwhile, the company also is developing doripenem for complicated urinary tract infections, including pyelonephritis. The company initiated its second pivotal Phase III in that indication two months ago. The primary endpoint is microbiological response five to nine days following completion of therapy in those patients who have been enrolled in the clinical study with a confirmed bacterial pathogen.

The company is developing an inhaled version of doripenem for the management of pulmonary infections in patients with cystic fibrosis.

Peninsula's other drug candidate, PPI-0903, also a member of the cephalosporin class of antibacterials, was developed as a water-soluble prodrug form of the bacteriocidal compound T-91825 by Takeda Chemical Industries Ltd., of Osaka.

PPI-0903 shows activity against Gram-positive and Gram-negative pathogens, including methicillin-resistant Staphylococcus aureus, vancomycin-intermediate S. aureus, linezolid-resistant S. aureus, and penicillin-resistant Streptococcus pneumoniae, the company said.

Peninsula and Takeda entered an exclusive license agreement to develop and commercialize PPI-0903 and/or pharmaceutical products containing PPI-0903 in all countries except Japan. Takeda will manufacture the product for worldwide distribution.

In late May, Peninsula said it initiated patient enrollment in a Phase I trial of an intravenous version of PPI-0903 for the treatment of complicated skin and skin-structure infections, community-acquired pneumonias and hospital-acquired pneumonias.