Cubist Acquires Calixa

Cubist Pharmaceuticals will acquire privately held Calixa Therapeutics for $92.5 million in cash, with $310 million in potential development, regulatory and commercial milestones. Both companies’ boards have approved the agreement, which is expected to close during 4Q09.

Calixa’s lead compound, CXA-201 is an intravenously administered combination of Calixa’s novel anti-pseudomonal cephalosporin CXA-101, which is currently in Phase II clinical trials for cUTI, and the β-lactamase inhibitor tazobactam. Cubist would obtain Calixa’s rights to develop and commercialize CXA-201, and other products that incorporate CXA-101 (previously FR264205), which Calixa acquired from Astellas Pharma Inc. Calixa has such rights in all territories of the world except select Asia-Pacific territories.

CXA-201 is being developed as a first-line intravenous therapy for the treatment of certain serious Gram-negative bacterial infections in the hospital, including those caused by multi-drug resistant P. aeruginosa. Its demonstrated potency against P. aeruginosa would give CXA-201 a highly differentiated profile versus marketed antibiotics. Cubist anticipates advancing the program for cUTI and cIAI in the first half of 2010. The next study in the cUTI program would take into consideration the results of the ongoing cUTI trial with CXA-101 and, in addition, a Phase II trial of CXA-201 for cIAI would be planned for the 1H10.

Cubist also would expect to begin clinical studies of CXA-201 for the nosocomial pneumonia indication in the second half of 2010. Assuming successful development, Cubist would expect to file an NDA for CXA-201 in the second half of 2013.

Cubist president and chief executive officer Michael Bonney said, “We are excited about the opportunity to add CXA-201 to our clinical pipeline. If successfully developed and launched, we believe that CXA-201 would be a potent weapon in the treatment of serious infections caused by multi-drug-resistant strains of the Gram negative pathogen Pseudomonas aeruginosa, playing a role similar to our Gram positive therapy Cubicin for the treatment of complicated skin infections and bacteremia caused by MRSA. We believe Cubist is ideally positioned to develop and commercialize this novel antibiotic that, assuming success, will provide physicians with a critically needed new weapon to treat certain serious infections caused by multi-drug-resistant Gram-negative pathogens, including those caused by Pseudomonas aeruginosa.”