MedImmune, Inc (GAITHERSBURG, Maryland), now wholly-owned by AstraZeneca plc, announced that dosing of patients has begun in the first phase I clinical trial of CAM-3001, a fully human monoclonal antibody targeting the alpha subunit of the granulocyte-macrophage colony stimulating factor receptor (GM-CSFR). The study is designed to evaluate the safety and tolerability of single doses of CAM-3001 in patients with rheumatoid arthritis (RA), and represents the first clinical trial in which a monoclonal antibody targeting GM-CSFR is being investigated in this population.

In this dose-escalation trial, patients will receive CAM- 3001 at Charité Research Organisation in Berlin, Germany, across a range of escalating doses, and they will be monitored for up to 7 months.

CAM-3001, which was isolated and optimized at MedImmune's Cambridge, UK facility (formerly known as Cambridge Antibody Technology), inhibits GM-CSF signaling, which has the potential for a significant anti-inflammatory effect. There is substantial evidence for a role of GM-CSF in RA. In preclinical studies, CAM- 3001 has demonstrated potent inhibition of GM-CSF mediated effects in a range of in vitro and in vivo assays relevant to RA. Additionally, elevated levels of GM-CSF and its receptor have been found in the joints of patients with RA.

MedImmune currently holds exclusive, worldwide rights to develop and market CAM-3001 under an agreement with CSL Ltd. In 2001, MedImmune's Cambridge facility and AMRAD Operations Pty Ltd (now owned by CSL Limited) entered into a collaboration to jointly discover and develop human monoclonal antibody therapeutics that neutralize the GM-CSF receptor, including CAM-3001. Under the terms of a subsequent licensing agreement entered into in August 2007, CSL will receive upfront and milestone payments as well as royalties on future sales of CAM-3001.