January 3, 2007

Theravance announced that the first patient has been treated in its Phase II clinical study of TD-1792, an investigational heterodimer antibiotic, for the treatment of complicated skin and skin structure infections (cSSSI) caused by Gram-positive bacteria, including resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). The goal of this program is to develop a next-generation antibiotic that is more efficacious than vancomycin, the current standard of care for the treatment of serious infections caused by MRSA, and that has an improved resistance profile relative to other available antibiotics.

TD-1792 is a unique heterodimer antibiotic that combines the antibacterial activities of a glycopeptide and a beta-lactam in one molecule, according to the company. Theravance initiated the Phase II program based on favorable data from preclinical and Phase I studies completed during 2006. In randomized, double-blind, placebo-controlled, single- and multiple-ascending dose Phase I studies that enrolled a total of 51 healthy volunteers TD-1792 was generally well tolerated and displayed linear pharmacokinetics and exposure profiles consistent with once-daily dosing. In preclinical in vitro studies, TD-1792 demonstrated marked bactericidal activity and was approximately 30 times more potent than vancomycin against MRSA and approximately 100 times more potent than oxacillin against methicillin-sensitive Staphylococcus aureus.

The Phase II randomized, double-blind, active-controlled study is designed to evaluate the safety and efficacy of TD-1792 in patients with cSSSI due to Gram-positive bacteria such as MRSA. Patients will be randomized to receive either TD-1792 dosed once daily or vancomycin dosed twice daily for up to 14 days. The study will be conducted in the United States with a goal of enrolling approximately 200 patients.