Calixa Therapeutics Announces Positive Phase 1 Results for CXA-101, a Novel Intravenous...

Calixa Therapeutics Announces Positive Phase 1 Results for CXA-101, a Novel
Intravenous Cephalosporin Antibiotic with Excellent Anti-Pseudomonal Activity

SAN DIEGO, March 24 /PRNewswire/ -- Calixa Therapeutics Inc. today announced
positive results from a Phase 1 trial of intravenous CXA-101, a novel
cephalosporin antibiotic with excellent in vitro anti-pseudomonal activity.

The results from this first Phase 1 study demonstrated that CXA-101 was well
tolerated, with a clinical and laboratory safety profile similar to that of
marketed cephalosporin antibiotics. No dose-limiting toxicity was observed,
even at the highest dose regimen evaluated. In addition, CXA-101 demonstrated
predictable, linear pharmacokinetics after intravenous administration in
humans. The results of this study fully support the further clinical
development of this compound.

"Pseudomonas aeruginosa is usually less susceptible to commonly used
antibiotics, and infections caused by this organism are often severe and very
difficult to treat," said Ian Friedland, M.D., chief medical officer of Calixa
Therapeutics. "There is a need for a safe and efficacious antibiotic to treat
pseudomonal infections. Unfortunately, the pipeline for such drugs is
virtually empty. The promising results in Phase 1 will enable us to quickly
advance CXA-101 into Phase 2 to evaluate its safety and efficacy in patients."

The completed Phase 1 trial was designed as a single- and multiple-ascending
dose study to assess the safety, tolerability and pharmacokinetic profile of
the compound in healthy volunteers. The study was successfully conducted in
the U.S. under an IND.

"Our development program is progressing well with our team that has a proven
track record in the anti-infective field," said Eckard Weber, M.D., CEO and
president of Calixa Therapeutics. "The Phase 1 data suggest a well-tolerated
drug with an excellent profile for potential clinical use as a treatment of
gram-negative bacterial infections."

Calixa Therapeutics acquired the global development rights (exclude certain
Asia-Pacific territories) to CXA-101 (FR264205) from Astellas Pharma Inc. in
2007. CXA-101's potent in vitro activity against Pseudomonas aeruginosa has
the potential to address the unmet medical need posed by this very problematic
gram-negative pathogen, which is a common cause of serious infection
associated with high morbidity and mortality. Nonclinical studies have shown
CXA-101 is highly active against multiple drug-resistant Pseudomonas
aeruginosa, including many strains resistant to carbapenems, an antibiotic
class generally considered as having the most potent activity against
resistant gram-negative pathogens.

About Calixa Therapeutics

Calixa Therapeutics Inc. is a biopharmaceutical company committed to the
development and commercialization of novel medicines for the treatment of
infectious diseases. The company's initial focus is on developing novel
antibiotics for use in the hospital setting. Calixa Therapeutics, which is
privately held, is headquartered in San Diego and has operations in the San
Francisco Bay Area. For additional information, please visit:
www.calixainc.com.

Contacts:

Robert Flamm, Ph.D., or David Schull
Russo Partners
(212) 845-4226
robert.flamm@russopartnersllc.com
david.schull@russopartnersllc.com

Eckard Weber, M.D.
Calixa Therapeutics Inc.
(858) 480-2420
stone@domainvc.com

SOURCE Calixa Therapeutics Inc.

Robert Flamm, Ph.D., robert.flamm@russopartnersllc.com, or David Schull,
david.schull@russopartnersllc.com, both of Russo Partners, +1-212-845-4226; or
Eckard Weber, M.D., of Calixa Therapeutics Inc., +1-858-480-2420,
stone@domainvc.com