Sunesis and Biogen to Discover Oral Therapeutics For Inflammatory and Immunological Diseases

Sunesis Pharmaceuticals, Inc. announced today that the company has entered into a collaboration with Biogen, Inc. (Nasdaq: BGEN) to discover oral therapeutics for the treatment of inflammatory and autoimmune diseases. The collaboration will apply Sunesis’ proprietary fragment-based drug discovery technology, known as “Tethering,” to generate small molecule leads that target select
cytokines in the immune system.

During the initial phase of the collaboration, both companies will contribute scientists and discovery resources to the collaboration. Under an exclusive worldwide license to compounds resulting from these efforts, Biogen will have the right to develop, manufacture and commercialize collaboration compounds.

Under the terms of the agreement, Sunesis will receive an up-front technology access fee, future quarterly payments, a minority equity investment and a loan over the first 30 months of the collaboration. Sunesis may receive up to $60 million in pre-commercialization milestones per target as well as significant royalty payments based on product sales. This collaboration includes four related cytokines and up to two additional targets.

James Young, Ph.D., CEO of Sunesis, commented, “We are excited to be entering into this broad collaboration with Biogen, clearly one of the preeminent biotechnology companies. Biogen’s considerable biological and therapeutic expertise combined with Sunesis’ proprietary fragment-based discovery approach will be a powerful combination to advance this important program.”

“There’s a tremendous need for orally active therapeutics that address these high impact targets in the immune system,” said Michael Gilman, Ph.D., Senior Vice President, Research at Biogen. “They are tough targets for small molecules. But Sunesis’ technology, coupled with Biogen’s expertise in immunology and medicinal chemistry, provides us with a way to tackle them — and the potential to deliver significant value to patients.”

Technology Overview
Sunesis’ fragment-based technology platform reliably generates novel hits against challenging targets by identifying binding ligands that other techniques such as high-throughput screening are too insensitive to find. Sunesis scientists screen libraries of fragments, fundamental building blocks of oral therapeutics, against validated targets that have been resistant to small molecule discovery. The basis for this approach is Tethering, a process in which the target selects fragments with binding affinity for a specific region on the target surface. By discovering drugs in pieces, Sunesis can effectively search a chemical diversity space
equivalent to hundreds of millions of compounds.

About Biogen
Biogen is the world’s oldest independent biotechnology company and a leader in biologics research, development and manufacturing. A pioneer in leading-edge research in immunology, neurobiology and oncology, Biogen brings novel therapies to improve patients’ lives around the world through its global marketing capabilities. For press releases and additional information about the company, please visit

About Sunesis
Sunesis is a leading discovery-based pharmaceutical company that applies its breakthrough fragment-based technologies to create superior oral therapeutics for the most challenging and important disease targets. Sunesis is building a pipeline of innovative
therapeutics addressing major diseases through internal development and selective partnering.

SOURCE Sunesis Pharmaceuticals, Inc. 01/07/2003
CONTACT: Media – Amy McKnight, Associate Director, Public Affairs,
+1-617-914-6524, Investors – Christina Dillon, Manager, Investor Relations, +1-617-679-2812, both of Biogen, Inc.;
Dan Swisher, CFO & Chief Business Officer of Sunesis Pharmaceuticals, Inc., +1-650-266-3715; Investors – Blair Clark, Media – Justin Jackson and Tricia Morsch, all of Burns McClellan Inc., +1-212-213-0006, for Sunesis Pharmaceuticals, Inc./