Chiron Corporation and XOMA Ltd. initiated a second clinical trial of CHIR-12.12, a novel, fully human, antagonist antibody that targets the CD40 antigen. The Phase I trial is for patients with multiple myeloma, a type of cancer that is associated with expression of the CD40 antigen on the cancer cell surface.

Chiron and XOMA announced the initiation of a Phase I clinical trial of CHIR-12.12 in patients with chronic lymphocytic leukemia in April 2005. CHIR-12.12 is the first drug candidate to enter clinical testing under the collaborative agreement between Chiron and XOMA for the development and commercialisation of antibody products for the treatment of cancer.

"Chiron's translational-medicine approach to drug development has helped identify diseases against which CHIR-12.12 may be effective, providing us with data that supports our decision to move forward with studies in multiple areas," said Stephen Dilly, chief medical officer, Chiron BioPharmaceuticals.

According to a company release, the single-agent, open-label Phase I study of CHIR-12.12 is designed to evaluate the safety, dose tolerability and pharmacokinetic profile of CHIR-12.12 in patients with multiple myeloma. Translational medicine will be used to monitor biomarkers and allow correlation of these markers with response to CHIR-12.12 therapy, guiding the dosing regimen and the selection of responsive patient populations. The study is expected to enroll up to 40 patients at four leading cancer centers in the United States.

CHIR-12.12 is a fully human, antagonist antibody that targets the CD40 antigen. As shown in vitro in cell lines, in vivo in animal models and ex vivo in patient cells, CHIR-12.12 binds to tumour cells that express CD40 and antagonises (prevents) CD40 ligand-mediated growth and survival of malignant B cells.

Multiple myeloma, also known as myeloma or plasma cell myeloma, is a progressive hematologic (blood) cancer of the plasma cell (a type of B lymphocyte), an important part of the immune system that produces immunoglobulins (antibodies) to help fight infection and disease.