Seattle Genetics’ ASH 2012 Presentations Highlight ADCETRIS® and Demonstrate Leadership in the Development of Antibody-Drug Conjugates (ADCs)

Seattle Genetics’ ASH 2012 Presentations Highlight ADCETRIS® and Demonstrate Leadership in the Development of Antibody-Drug Conjugates (ADCs)

<0> Seattle Genetics, Inc.Investors:Peggy Pinkston, 425-527-4160orMedia:Tricia Larson, 425-527-4180 </0>

(Nasdaq:SGEN) today announced that more than a dozen abstracts, in addition to several collaborator abstracts, for both ADCETRIS (brentuximab vedotin) and investigational antibody-drug conjugates (ADCs) will be presented at the American Society of Hematology (ASH) Annual Meeting taking place in Atlanta, Georgia, December 8 – 11, 2012. ADCETRIS is an ADC directed to CD30, which is known to be expressed in Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL), as well as in some types of cutaneous T-cell lymphoma (CTCL), B-cell lymphomas and mature T-cell lymphomas (MTCL). Seattle Genetics is broadly evaluating CD30 expression in many other cancer types. ADCETRIS is currently not approved for use in CTCL, B-cell lymphomas, and front-line treatment of HL or MTCL.

"The comprehensive data presented at ASH 2012 support our goal to establish ADCETRIS as the foundation of therapy for a broad array of CD30-positive malignancies and redefine therapy in the front-line setting of HL and MTCL,” said Clay B. Siegall, Ph.D., President and Chief Executive Officer of Seattle Genetics. "As a pioneer in developing ADC therapies, we continue to innovate by expanding the ADCETRIS program into CD30-positive malignancies, advancing additional ADC pipeline candidates, and supporting the progress of our collaborator ADC programs. These important advances represent our continued innovation and ADC leadership position."

Seattle Genetics is the leader in developing ADCs, a technology designed to harness the targeting ability of antibodies to deliver cell-killing agents directly to cancer cells. Of the approximately 30 ADC candidates currently in development, more than half utilize Seattle Genetics’ proprietary ADC technology. Multiple company, investigator and collaborator presentations will be presented at ASH, including data on ADCETRIS in many types of CD30-positive malignancies and preclinical data from a new ADC product candidate called SGN-CD33A. Abstract presentations planned at ASH can be found at and include the following:

ADCETRIS (brentuximab vedotin) is an ADC comprising an anti-CD30 monoclonal antibody attached by a protease-cleavable linker to a microtubule disrupting agent, monomethyl auristatin E (MMAE), utilizing Seattle Genetics’ proprietary technology. The ADC employs a linker system that is designed to be stable in the bloodstream but to release MMAE upon internalization into CD30-expressing tumor cells.

ADCETRIS received accelerated approval from the U.S. Food and Drug Administration (FDA) for two indications: (1) the treatment of patients with Hodgkin lymphoma after failure of autologous stem cell transplant (ASCT) or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates, and (2) the treatment of patients with systemic anaplastic large cell lymphoma (sALCL) after failure of at least one prior multi-agent chemotherapy regimen. The indications for ADCETRIS are based on response rate. There are no data available demonstrating improvement in patient-reported outcomes or survival with ADCETRIS.

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

Seattle Genetics is a biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer. The FDA granted accelerated approval of ADCETRIS in August 2011 for two indications. ADCETRIS is being developed in collaboration with Millennium: The Takeda Oncology Company. In addition, Seattle Genetics has three other clinical-stage ADC programs: SGN-75, ASG-5ME and ASG-22ME. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including Abbott, Agensys (an affiliate of Astellas), Bayer, Celldex Therapeutics, Daiichi Sankyo, Genentech, GlaxoSmithKline, Millennium, Pfizer and Progenics, as well as ADC co-development agreements with Agensys and Genmab. More information can be found at .

Progressive multifocal leukoencephalopathy (PML): JC virus infection resulting in PML and death can occur in patients receiving ADCETRIS.

Concomitant use of ADCETRIS and bleomycin is contraindicated due to pulmonary toxicity.

ADCETRIS was studied as monotherapy in 160 patients in two phase 2 trials. Across both trials, the most common adverse reactions (≥20%), regardless of causality, were neutropenia, peripheral sensory neuropathy, fatigue, nausea, anemia, upper respiratory tract infection, diarrhea, pyrexia, rash, thrombocytopenia, cough and vomiting.

Drug Interactions:

Patients who are receiving strong CYP3A4 inhibitors concomitantly with ADCETRIS should be closely monitored for adverse reactions.

For additional important safety information, including Boxed WARNING, please see the full U.S. prescribing information for ADCETRIS at or .

Certain of the statements made in this press release are forward looking, such as those, among others, relating to our goal to establish ADCETRIS as the foundation of therapy for a broad array of CD30-positive malignancies. 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 risks that data resulting from additional trials with ADCETRIS will not support approvals in any of the studied indications. In addition, as our other drug candidates or those of our collaborators advance in clinical trials, adverse events may occur which affect the future development of those drug candidates and possibly other compounds using similar technology. More information about the risks and uncertainties faced by Seattle Genetics is contained in the company’s 10-Q for the quarter ended June 30, 2012 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.

Suggested Articles

Genentech followed a $1 billion pact with Sosei Heptares with discovery deals around cancer and neurological diseases with Skyhawk and Convelo.

The partners will use wearable devices to assess how heart failure patients function and feel after being discharged from hospitals.

After spinning out two companies at the start of the year, Sosei Heptares has now inked a new deal with Roche biologics unit Genentech.