KaloBios Pharmaceuticals is to receive $35 million up front from Sanofi Pasteur as part of the companies’ collaboration to develop KaloBios’ Phase II-stage antibody fragment KB001 for treating or preventing Pseudomonas aeruginosa infections. KaloBios could receive another $255 million in development, regulatory, and commercial milestones plus sales royalties.
Sanofi Pasteur will initially focus on developing and commercializing KB001 for hospital indications including the prevention of Pseudomonas aeruginosa pneumonias in mechanically ventilated patients. KalaBios will develop and commercialize the antibody fragment primarily for the treatment of patients with cystic fibrosis and bronchiectasis. Sanofi Pasteur has an option to acquire commercial rights to KaloBios’ indications for KB001 outside the U.S. and co-promotion rights within the U.S.
In October 2009, KalaBios reported positive results from a Phase I/II trial with the antibody fragment in cystic fibrosis patients with Pseudomonas aeruginosa infections. The company has also carried out a Phase I/II trial in mechanically ventilated patients.
KB001 is designed to block Pseudomonas aeruginosa’s type three secretion system virulence mechanism, which allows the organism to evade human immune defenses by killing white blood cells and epithelial cells and triggering tissue-damaging inflammation, KaloBios explains.
“KB001’s novel mechanism of action against Pseudomonas aeruginosa provides a unique means of fighting these infections, which are often resistant to antibiotic therapies,” states Tillman Pearce, M.D., KaloBios’ CEO. “We also think this novel mechanism could have a significant impact on Pseudomonas aeruginosa infections in cystic fibrosis patients as well.”
KB001 is KaloBios’ lead high-affinity anti-PcrV PEGylated antibody Fab' fragment, developed using the firm’s Humaneering™ technology. The company says that it developed this platform as a method for converting nonhuman antibodies into engineered human antibodies that have high affinity but are closer to human germline sequence than antibodies generated using other engineering methods.