NEW YORK (AP) — Biotechnology company Celgene Corp. on Friday said it will develop drugs intended to stimulate the immune system against cancer through a partnership with GlobeImmune Inc., in a deal that could be worth more than $500 million. Celgene will pay GlobeImmune $40 million upfront, which includes an investment in the privately held company. GlobeImmune will handle early-stage development of the drug candidates, which it calls Tarmogens, and Celgene will have the option to license the drugs, completing development and regulatory filings and selling the products. GlobeImmune will be eligible for milestone payments as the products are tested, and royalties on sales if they are approved. GlobeImmune's Tarmogen drucegs contain a genetically engineered yeast that also contains antibodies designed to fight disease. The drugs are intended to boost the body's immune system and help it fight the drug. The company has one drug candidate, called GI-4000, in mid-stage testing against pancreatic and non-small cell lung cancer. It is also testing drugs for hepatitis C, influenza, and glioblastoma, a form of brain cancer.