The UK pharmaceutical giant GlaxoSmithKline has secured a US$1.4-billion, five-year deal with the biotechnology company OncoMed Pharmaceuticals in Redwood City, California, to develop therapies based on cancer stem cells.

The deal, among the most lucrative ever for any preclinical company, has a certain risk because the cancer stem-cell theory is not universally accepted. The theory holds that tumours develop from specific stem cells that fail to be eliminated by chemotherapy and radiotherapy and thus reseed the cancer even after a long remission.

OncoMed has developed monoclonal antibodies to target and destroy such cancer stem cells. GlaxoSmithKline has secured the rights to four of them, which will now enter clinical trials.