BOTHELL, Wash., Apr 06, 2011 (BUSINESS WIRE) --

Seattle Genetics, Inc. (Nasdaq: SGEN) today announced that data from a case series of Hodgkin lymphoma patients receiving brentuximab vedotin (SGN-35) following allogeneic stem cell transplant were presented in an oral session at the European Group for Blood and Marrow Transplantation (EBMT) Annual Meeting in Paris, France. Brentuximab vedotin is an antibody-drug conjugate (ADC) directed to CD30, a defining marker of Hodgkin lymphoma.

This is the first report of data from brentuximab vedotin in Hodgkin lymphoma patients who relapsed following allogeneic transplant. Patients in the company's pivotal Hodgkin lymphoma trial had all relapsed following autologous transplant, but none had received an allogeneic transplant. Patients relapsing following allogeneic transplant represent a particularly difficult therapeutic challenge. Key findings from this case series of 25 post-allogeneic transplant patients include:

• 50 percent of patients achieved an objective response (12 of 24 evaluable), including 38 percent complete remissions; an additional 42 percent of patients had stable disease
• Median progression-free survival (PFS) was 34 weeks; median overall survival had not been reached
• The median time to objective response was 8.1 weeks and patients received a median of 8 cycles of therapy; five patients remain on treatment
• Brentuximab vedotin administration was associated with manageable adverse events, with the most common being cough, fatigue, fever, nausea and peripheral sensory neuropathy
• The most common Grade 3 or higher adverse events were neutropenia, anemia, fatigue and fever

"Although allogeneic stem cell transplantation is the only potentially curative option at present for Hodgkin lymphoma patients who relapse following an autologous transplant, only 20 to 25 percent of these patients achieve long-term benefit," said Owen A. O'Connor, M.D., Ph.D., Professor, and Director, Division of Hematology and Medical Oncology at NYU Cancer Institute. "There are currently no good treatment options for Hodgkin lymphoma patients who fail allogeneic transplant. These data for brentuximab vedotin are encouraging in this post-transplant setting where there is a significant unmet medical need."

The case series comprises data from Hodgkin lymphoma patients who relapsed following allogeneic stem cell transplant that were enrolled in one of three multicenter, open label clinical trials of brentuximab vedotin. Patients received 1.2 or 1.8 milligrams per kilogram of brentuximab vedotin every three weeks. The median age of patients was 32 years. Enrolled patients had received a median of five prior therapeutic regimens, including 76 percent who had a prior autologous stem cell transplant.

About Brentuximab Vedotin

Brentuximab vedotin is an ADC comprising an anti-CD30 monoclonal antibody attached by a protease-cleavable linker to a potent, synthetic drug, monomethyl auristatin E (MMAE) utilizing Seattle Genetics' proprietary technology. The ADC employs a novel linker system that is designed to be stable in the bloodstream but to release MMAE upon internalization into CD30-expressing tumor cells. This approach is intended to spare non-targeted cells and thus may help minimize the potential toxic effects of traditional chemotherapy while allowing for the selective targeting of CD30-expressing cancer cells, thus potentially enhancing the antitumor activity.

Seattle Genetics is jointly developing brentuximab vedotin with Millennium: The Takeda Oncology Company. Under the terms of the collaboration agreement, Seattle Genetics has U.S. and Canadian commercialization rights and the Takeda Group has rights to commercialize brentuximab vedotin in the rest of the world. Seattle Genetics and the Takeda Group are funding joint development costs for brentuximab vedotin on a 50:50 basis, except in Japan where the Takeda Group will be solely responsible for development costs.

About Hodgkin Lymphoma

Lymphoma is a general term for a group of cancers that originate in the lymphatic system. There are two major categories of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma is distinguished from other types of lymphoma by the presence of one characteristic type of cell, known as the Reed-Sternberg cell. A defining attribute of the Reed-Sternberg cell is its expression of the CD30 antigen.

According to the American Cancer Society, approximately 8,500 cases of Hodgkin lymphoma were diagnosed in the United States during 2010 and more than 1,300 died from the disease. Although front-line combination chemotherapy can result in durable response rates, up to 30 percent of these patients relapse or are refractory to front-line treatment and have few therapeutic options beyond autologous stem cell transplant.

About Seattle Genetics

Seattle Genetics is a clinical-stage biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer and autoimmune disease. The company submitted a Biologics License Application to the U.S. Food and Drug Administration for its lead product candidate, brentuximab vedotin, for the treatment of relapsed or refractory Hodgkin lymphoma and systemic anaplastic large cell lymphoma in February 2011. Brentuximab vedotin is being developed in collaboration with Millennium: The Takeda Oncology Company. In addition, Seattle Genetics has four other clinical-stage programs: SGN-75, ASG-5ME, dacetuzumab (SGN-40) and SGN-70. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including Abbott, Bayer, Celldex Therapeutics, Daiichi Sankyo, Genentech, GlaxoSmithKline, Millennium, Pfizer and Progenics, as well as ADC co-development agreements with Agensys, an affiliate of Astellas, and Genmab. More information can be found at www.seattlegenetics.com.

Certain of the statements made in this press release are forward-looking, such as those, among others, relating to the potential therapeutic benefit of brentuximab vedotin. Actual results or developments may differ materially from those projected or implied in these forward-looking statements. Factors that may cause such a difference include that the safety and/or efficacy results of the pivotal trial in relapsed or refractory Hodgkin lymphoma and phase II trial in relapsed or refractory systemic ALCL will not be sufficient to gain marketing approval in the United States or any other country, that we will be required to amend our submission for marketing approval or that such submission will be refused. In addition, our regulatory plans may change as a result of consultation with the FDA or EMA. More information about the risks and uncertainties faced by Seattle Genetics is contained in the company's 10-K for the year ended December 31, 2010 filed with the Securities and Exchange Commission. Seattle Genetics disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

SOURCE: Seattle Genetics, Inc.

Seattle Genetics, Inc.
Peggy Pinkston, 425-527-4160
ppinkston@seagen.com