Bristol-Myers Squibb Company and Medarex Inc. have formed a worldwide collaboration to develop and commercialize MDX-010, a fully human antibody investigational product targeting the CTLA-4 receptor.

MDX-010 was developed by Medarex using its UltiMAb Human Antibody Development System and is currently in phase III clinical development for the treatment of metastatic melanoma. There are more than 160,000 cases of melanoma diagnosed worldwide, and 40,000 annual deaths. The agreement is subject to receipt of various governmental clearances and approvals, including clearance under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.

The collaboration also includes MDX-1379, an investigational gp100 peptide vaccine, which will be developed for potential use in combination with MDX-010 in melanoma. Bristol-Myers Squibb and Medarex have agreed to jointly continue to investigate the development of MDX-010 in additional tumour types. Bristol-Myers Squibb and Medarex will share in the costs of developing MDX-010 and MDX-1379 in the United States and Europe based on a pre-agreed percentage allocation. Bristol-Myers Squibb will be responsible for all development outside of these territories.

Medarex will receive an initial cash payment of $50 million, of which $25 million will be a purchase of Medarex's common stock by Bristol-Myers Squibb at a premium to the market price. Medarex could receive up to $205 million if all regulatory milestones are met, and up to $275 million in sales-related milestones. Medarex will have an option to co-promote and share profits with Bristol-Myers Squibb in the United States based on a pre-agreed percentage split. Bristol-Myers Squibb will receive an exclusive license ex-US and pay royalties to Medarex, Medarex said in a release.

MDX-010 is a fully human antibody against human CTLA-4, a molecule on T cells that is believed to be responsible for suppressing the immune response. MDX-010 also has the potential to enable the immune systems of cancer patients to more effectively fight tumours. In June 2004, MDX-010 received orphan drug designation from the US FDA for the treatment of high risk Stage II, Stage III and Stage IV melanoma.

The FDA has granted Fast Track status to MDX-010 in combination with MDX-1379 for treatment of patients with late stage unresectable metastatic melanoma who have failed or are intolerant to first line therapy. MDX-1379 - a melanoma peptide vaccine - is part of the global collaboration with Bristol-Myers Squibb, and the combination treatment is currently in Phase III clinical trials.