FDA grants Seattle Genetics orphan drug designation for ADCETRIS to treat mycosis fungoides

Seattle Genetics, Inc. (Nasdaq: SGEN) announced today that ADCETRIS (brentuximab vedotin) has been granted orphan drug designation by the U.S. Food and Drug Administration (FDA) for the treatment of mycosis fungoides (MF). MF is the most common type of cutaneous T-cell lymphoma (CTCL). Seattle Genetics and its ADCETRIS collaborator, Millennium: The Takeda Oncology Company, are conducting the ALCANZA trial, a phase III clinical trial of ADCETRIS for patients with CD30-positive relapsed CTCL, including MF. ADCETRIS is not approved for the treatment of CTCL.

“The encouraging data from investigator-sponsored trials of ADCETRIS in CTCL, which will be presented at ASH, provide further support for our activities in this patient population.”

"This orphan drug designation is a part of our ADCETRIS regulatory strategy, designed to complement the Special Protocol Assessment for the ongoing ALCANZA study," said Clay B. Siegall, President and Chief Executive Officer of Seattle Genetics. "The encouraging data from investigator-sponsored trials of ADCETRIS in CTCL, which will be presented at ASH, provide further support for our activities in this patient population."

FDA orphan drug designation is intended to encourage companies to develop therapies for the treatment of diseases that affect fewer than 200,000 individuals in the United States. This designation provides Seattle Genetics with the opportunity for seven years of marketing exclusivity, grant funding to defray costs of clinical trial expenses, tax credits for clinical research expenses and potential waiver of the FDA's application user fee.

The ALCANZA trial is a randomized phase III clinical trial of ADCETRIS for relapsed CD30-positive CTCL patients. The trial is assessing ADCETRIS versus investigator's choice of methotrexate or bexarotene in patients with CD30-positive CTCL, including those with primary cutaneous anaplastic large cell lymphoma (pcALCL) or MF. The primary endpoint of the study is overall response rate lasting at least 4 months. Approximately 124 patients will be enrolled in the pivotal trial. The ALCANZA trial is being conducted under a Special Protocol Assessment agreement from the FDA. The study also received European Medicines Agency scientific advice. For more information about the ALCANZA trial, visit www.clinicaltrials.gov.

At the 54^th American Society of Hematology (ASH) Annual Meeting and Exposition being held December 8-11, 2012 in Atlanta, GA, data from two investigator-sponsored trials of ADCETRIS in CTCL will be reported:

Brentuximab vedotin demonstrates significant clinical activity in relapsed or refractory mycosis fungoides with variable CD30 expression (Abstract #797)

• Oral presentation on Monday, December 10; 7:15 p.m. Eastern Time (ET) in Rooms B304-B305
• First author: Dr. Michael Krathen, Stanford University, Stanford, CA

Results of a phase II trial of brentuximab vedotin (SGN-35) for CD30-positive cutaneous T-cell lymphomas and lymphoproliferative disorders (Abstract #3688)

• Poster presentation on Monday, December 10; 6:00 p.m. to 8:00 p.m. ET in Hall B1-B2
• First author: Dr. Madeleine Duvic, The University of Texas MD Anderson Cancer Center, Houston, TX