Cubist Gram-negative: CB-182,804

Cubist's lipopeptide Gram-negative program is focused on identifying antibiotic candidates with efficacy in treating infections caused by multi-drug resistant Gram-negative pathogens, which include Escherichia, Klebsiella, Pseudomonas, and Acinetobacter. We believe successful new agents need to be effective against all four, which is no easy task. Drug resistant Gram-negative bacterial infections are another area of significant unmet medical need, particularly in acute care settings.

Cubist began a Phase 1 single-ascending-dose study of our compound CB-182,804 in Q1 09 (IND submission 12-23-08). Pre-clinical studies have shown this compound to have promise as a potent, cidal, I.V. antibiotic for Gram-negative infections. In particular, it has demonstrated rapid cidality in vitro against multi-drug-resistant bacteria including: P. aeruginosa, E. coli, K. pneumoniae, A. baumannii. The Phase 1 evaluation of CB-182,804 is nearing completion. We decided to amend our Phase 1 protocol to add an additional dosing cohort to confirm the expected safety margin at projected therapeutic doses. As a result, our Phase 2 Go/ No Go decision timing on this program will now shift from 1Q10 to this summer.