Seattle Genetics Reports Durable Objective Responses with SGN-35 in Lymphoma

Seattle Genetics, Inc. has reported data from a phase I clinical trial of SGN-35, an antibody-drug conjugate (ADC), demonstrating multiple complete and partial responses at well-tolerated doses in patients with relapsed or refractory Hodgkin lymphoma and other CD30-positive hematologic malignancies.

The data were presented during the American Society of Hematology (ASH) 50th Annual Meeting in San Francisco, California. Based on data from the phase I study, the company is finalizing its U.S. registration pathway and plans to initiate pivotal trials of SGN-35 in the first half of 2009.

Out of 44 evaluable patients treated with SGN-35, 17 patients achieved objective responses, including nine complete responses and eight partial responses. Eighteen additional patients had stable disease and nine patients progressed. The median duration of response was 22 weeks, with 11 responses still ongoing.

Across all dose levels, 86 percent of the 42 patients who had at least one post-baseline assessment achieved reductions in tumor volume. Among 28 evaluable patients treated at doses of 1.2 milligrams per kilogram (mg/kg) and higher, 54 percent achieved an objective response, including 32 percent with complete responses.

Furthermore, 93 percent of these patients achieved tumor reductions, and their median progression-free survival was greater than six months.

“Patients with Hodgkin lymphoma who relapse following stem cell transplant have limited therapeutic options, and those who relapse within six months have a short predicted survival,” said Anas Younes, M.D., Professor of Medicine and Director, Clinical and Translational Research in the Department of Lymphoma/Myeloma at MD Anderson Cancer Center, and presenting investigator of the phase I study.

“These phase I data are encouraging, and provide evidence that SGN-35 may offer an important new therapeutic option for patients in this setting.”