Seattle Genetics, Inc. (Nasdaq: SGEN) and Millennium: The Takeda Oncology Company with its parent company Takeda Pharmaceutical Company Limited (TSE:4502), reported updated data from a pivotal trial of single-agent ADCETRIS in relapsed or refractory systemic anaplastic large cell lymphoma (sALCL) at the 53rd American Society of Hematology (ASH) Annual Meeting and Exposition being held December 10-13, 2011 in San Diego, CA.

ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30, which is expressed in ALCL.

“This clinical trial demonstrates that durable complete remissions can be achieved with ADCETRIS in this aggressive type of T-cell lymphoma that expresses CD30,” said Dr. Ranjana Advani, Professor of Medicine/Oncology at Stanford University Medical Center. “These data reinforce the role of ADCETRIS in relapsed or refractory systemic ALCL patients, and its potential to provide an important therapeutic option for eligible patients.”

Brentuximab Vedotin in Patients with Relapsed or Refractory Systemic Anaplastic Large Cell Lymphoma: A Phase 2 Study Update (Abstract #443)

A pivotal trial was conducted in 58 relapsed or refractory sALCL patients. The primary endpoint was overall objective response rate per independent review. Key updated data, which were presented by Dr. Advani, included:

• Eighty-six percent of patients achieved an objective response with a median duration of 13.2 months
• Fifty-nine percent of patients achieved a complete remission (CR)
• Median duration of CRs has not yet been reached
• Median follow-up from first dose of ADCETRIS in all patients was 14.7 months
• Median progression-free survival (PFS) in patients treated with ADCETRIS was 14.5 months compared to 5.9 months for the most recent prior therapy received by these patients
• Median PFS of anaplastic lymphoma kinase (ALK)-positive patients was 14.6 months compared to 14.3 months in ALK-negative patients
• Estimated overall survival rate of patients at one year was 70 percent
• The most common adverse events considered related to ADCETRIS of any Grade were peripheral sensory neuropathy (45 percent), fatigue (28 percent), nausea (28 percent), diarrhea (19 percent), neutropenia (17 percent) and myalgia (16 percent)
• The most common Grade 3 or higher adverse events considered related to ADCETRIS were neutropenia (17 percent), peripheral sensory neuropathy (12 percent) and diarrhea (3 percent)

This single-arm trial assessed efficacy and safety of single-agent ADCETRIS in relapsed or refractory sALCL patients. Patients received 1.8 milligrams per kilogram of ADCETRIS every three weeks for up to 16 total cycles. The median age of patients in the pivotal trial was 52 years. Enrolled patients had received a median of two prior chemotherapy regimens.

About ADCETRIS

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.

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.

ADCETRIS was granted accelerated approval by the U.S. Food and Drug Administration in August 2011 for two indications: (1) the treatment of patients with HL 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 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.

ADCETRIS is not approved for use outside the United States. The marketing authorization application for ADCETRIS in relapsed or refractory Hodgkin lymphoma and sALCL, filed by Takeda Global Research & Development Centre (Europe), was accepted by the European Medicines Agency in June 2011.

About Seattle Genetics

Seattle Genetics is a biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer. ADCETRIS was approved by the FDA on August 19, 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, 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.

About Millennium

Millennium: The Takeda Oncology Company, a leading biopharmaceutical company based in Cambridge, Mass., markets a first-in-class proteasome inhibitor in the US, and has a robust clinical development pipeline of global product candidates. Millennium Pharmaceuticals, Inc. was acquired by Takeda Pharmaceutical Company Ltd. in May, 2008. The Company’s research, development and commercialization activities are focused in oncology. Additional information about Millennium and Takeda are available through their respective websites, http://www.millennium.com

and http://www.takeda.com.

About Takeda

Located in Osaka, Japan, Takeda is a research-based global company with its main focus on pharmaceuticals. As the largest pharmaceutical company in Japan and one of the global leaders of the industry, Takeda is committed to strive towards better health for patients worldwide through leading innovation in medicine. Additional information about Takeda is available through its corporate website, www.takeda.com.

U.S. Important Safety Information

Warnings and Precautions:

• Peripheral neuropathy: ADCETRIS treatment causes a peripheral neuropathy that is predominantly sensory. Cases of peripheral motor neuropathy have also been reported. ADCETRIS-induced peripheral neuropathy is cumulative. Treating physicians should monitor patients for symptoms of neuropathy, such as hypoesthesia, hyperesthesia, paresthesia, discomfort, a burning sensation, neuropathic pain or weakness and institute dose modifications accordingly.
• Infusion reactions: Infusion-related reactions, including anaphylaxis, have occurred with ADCETRIS. Monitor patients during infusion. If an infusion reaction occurs, the infusion should be interrupted and appropriate medical management instituted. If anaphylaxis occurs, the infusion should be immediately and permanently discontinued and appropriate medical management instituted.
• Neutropenia: Monitor complete blood counts prior to each dose of ADCETRIS and consider more frequent monitoring for patients with Grade 3 or 4 neutropenia. If Grade 3 or 4 neutropenia develops, manage by dose delays, reductions or discontinuation. Prolonged (≥1 week) severe neutropenia can occur with ADCETRIS.
• Tumor lysis syndrome: Patients with rapidly proliferating tumor and high tumor burden are at risk of tumor lysis syndrome and these patients should be monitored closely and appropriate measures taken.
• Stevens-Johnson syndrome: Stevens-Johnson syndrome has been reported with ADCETRIS. If Stevens-Johnson syndrome occurs, discontinue ADCETRIS and administer appropriate medical therapy.
• Progressive multifocal leukoencephalopathy (PML): A fatal case of PML has been reported in a patient who received four chemotherapy regimens prior to receiving ADCETRIS.
• Use in pregnancy: Fetal harm can occur. Pregnant women should be advised of the potential hazard to the fetus.

Adverse Reactions:

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, please see the full U.S. prescribing information for ADCETRIS at www.seattlegenetics.com or www.ADCETRIS.com.

For Seattle Genetics:

Certain of the statements made in this press release are forward looking, such as those, among others, relating to the therapeutic potential of ADCETRIS and potential approval in countries outside the United States. 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 the inability to show sufficient activity in the clinical trials presented for approval in Europe. In addition, data from our clinical trials, including our pivotal trials which were the basis for FDA accelerated approval, may not necessarily be indicative of subsequent clinical trial results. More information about the risks and uncertainties faced by Seattle Genetics is contained in the company’s 10-Q for the quarter ended September 30, 2011 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.

Photos/Multimedia Gallery Available: http://www.businesswire.com/cgi-bin/mmg.cgi?eid=50102669&lang=en