GlaxoSmithKline  (GSK) and Synta Pharmaceuticals Corp.  the execution of a global collaboration agreement for the joint development and commercialization of STA-4783, a first-in-class, small-molecule, oxidative stress inducer that is entering Phase 3 clinical development for the treatment of metastatic melanoma. 

(GSK) and Synta Pharmaceuticals Corp.  will share responsibility for development and commercialization of STA-4783 in the U.S. and GSK will have exclusive responsibility for development and commercialization of STA-4783 outside the U.S.

Melanoma, the most deadly form of skin cancer, arises from melanocytes, the pigment-producing cells of the skin.

STA-4783 is a novel, injectable, investigational drug candidate that kills cancer cells by elevating oxidative stress levels beyond a breaking point, triggering programmed cell death. In preclinical models STA-4783 showed potent killing of a broad range of cancer cell types at high doses, and an ability to strongly enhance the efficacy of certain chemotherapy agents, with minimal additional toxicity, at moderate doses.

Synta will receive an upfront cash payment of $80 million. Synta will also be eligible to receive potential milestone payments of up to $135 million for events leading to approval of STA-4783 in metastatic melanoma, further development and regulatory milestones of up to $450 million across various indications and up to $300 million in potential commercial milestone payments based on achieving certain net sales thresholds.

Synta will continue to fund all development for metastatic melanoma in the U.S. and the companies will share responsibility and costs for development of STA-4783 in other indications. Synta and GSK will jointly commercialize STA-4783 in the U.S. with Synta receiving a tiered profit share based on levels of annual net sales. The parties will share development costs outside of the U.S. and Synta will receive double-digit tiered royalties on net sales. In addition, GSK may, subject to Synta’s agreement, purchase, up to $45 million of Synta’s common stock upon the future achievement of specified development and regulatory milestones.

The agreement is subject to antitrust clearance by the U.S. government under the Hart-Scott-Rodino Act. Common stock purchases may be subject to approval of Synta’s shareholders if required under the rules and regulations of The Nasdaq Stock Market.

GlaxoSmithKline, one of the world’s leading research-based pharmaceutical and healthcare companies, is committed to improving the quality of human life by enabling people to do more, feel better and live longer.

Synta Pharmaceuticals Corp. is a biopharmaceutical company focused on discovering, developing, and commercializing small molecule drugs to extend and enhance the lives of patients with severe medical conditions, including cancer and chronic inflammatory diseases.