The US Food & Drug Administration (FDA) has granted orphan drug designation to KaloBios Pharmaceuticals' KB001-A, an anti-PcrV monoclonal antibody (mAb) fragment, for the treatment of cystic fibrosis (CF) patients with Pseudomonas aeruginosa (Pa).

KaloBios is currently enrolling patients in a phase II multiple-dose, randomized, double-blind, placebo-controlled clinical trial with KB001-A in CF patients chronically infected with Pa. This 180-patient study is intended to evaluate the efficacy and safety of repeat doses of KB001-A. The primary endpoint is time-to-need for antibiotics.

"The FDA's designation of KB001-A as an orphan drug is another milestone for KaloBios as we continue the clinical development work required for potential FDA approval," said David W Pritchard, KaloBios' president and CEO. "We are working hard to complete enrollment of our phase II trial and look forward to evaluating and reporting on the activity of KB001-A in late 2014."

Orphan drug designation is granted by the FDA Office of Orphan Products Development to novel drugs or biologics that treat a rare disease or condition affecting fewer than 200,000 patients in the United States. The designation provides the drug developer with a seven-year period of US marketing exclusivity if the drug is the first of its type approved for the specified indication or if it demonstrates superior safety, efficacy, or a major contribution to patient care versus another drug of its type that was previously granted the designation for the same indication. Orphan designation also provides tax credits for clinical research costs, the ability to apply for annual grant funding, clinical research trial design assistance and waiver of Prescription Drug User Fee Act (PDUFA) filing fees.

KaloBios Pharmaceuticals, Inc. is developing a portfolio of proprietary, patient-targeted, first-in-class monoclonal antibodies designed to treat severe life-threatening or debilitating diseases for which there is an unmet medical need, with a clinical focus on severe respiratory diseases and cancer.