BOTHELL, Wash.--(BUSINESS WIRE)--Seattle Genetics, Inc. (Nasdaq: SGEN) today announced that it has reached agreement with the U.S. Food and Drug Administration (FDA) on a Special Protocol Assessment (SPA) for a pivotal trial of SGN-35, an antibody-drug conjugate (ADC), for patients with relapsed or refractory Hodgkin lymphoma. The SPA provides an agreement between the FDA and Seattle Genetics regarding the design, including size and clinical endpoints, of the pivotal trial to support an efficacy claim in a New Drug Application (NDA).