Health Canada Approves ADCETRIS® (Brentuximab Vedotin) for the Treatment of Relapsed or Refractory Hodgkin Lymphoma (HL) and

  Health Canada Approves ADCETRIS® (Brentuximab Vedotin) for the Treatment of
  Relapsed or Refractory Hodgkin Lymphoma (HL) and Systemic Anaplastic Large
  Cell Lymphoma (sALCL)

     - ADCETRIS is the First in a New Class of Targeted Therapies Called
                          Antibody-Drug Conjugates -

Business Wire

BOTHELL, Wash. -- February 1, 2013

Seattle Genetics, Inc. (Nasdaq:SGEN) today announced that Health Canada has
issued a Notice of Compliance with conditions (NOC/c), authorizing marketing
of ADCETRIS for two lymphoma indications: (1) the treatment of patients with
Hodgkin lymphoma (HL) after failure of autologous stem cell transplant (ASCT)
or after failure of at least two 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
multi-agent chemotherapy regimen. The indications for ADCETRIS were authorized
based on promising response rates demonstrated in single-arm trials. No data
demonstrate increased survival with ADCETRIS.

“We are focused on making ADCETRIS available globally to all eligible patients
with relapsed HL and sALCL. The approval of ADCETRIS in Canada, as well as the
recent approval in the European Union, are important milestones to accomplish
this goal,” said Clay B. Siegall, Ph.D., President and Chief Executive Officer
of Seattle Genetics. “Now that Health Canada has approved ADCETRIS, we are
committed to working closely with public and private insurers to secure
reimbursement coverage for patients in Canada.”

“The approval of ADCETRIS in Canada marks a significant milestone for patients
with relapsed HL or sALCL who have had few new treatment options in several
decades,” Joseph M. Connors, M.D., FRCPC, Clinical Director, Center for
Lymphoid Cancer at BC Cancer Agency in Vancouver, Canada.

Health Canada grants NOC/c, a form of market approval, on the basis of
promising evidence of clinical effectiveness, for products intended for the
treatment of serious, life-threatening or severely debilitating illnesses that
meet a serious unmet medical need or demonstrate a significant improvement in
the benefit/risk profile over existing therapies. Conditions associated with
market authorization under the NOC/c policy include a requirement that Seattle
Genetics conduct clinical trials designed to confirm the anticipated clinical
benefit of ADCETRIS in these patients. Two confirmatory phase III clinical
trials evaluating ADCETRIS in the front-line treatment setting of HL and
mature T-cell lymphoma (MTCL), including sALCL, are currently underway and
enrolling patients.

ADCETRIS (brentuximab vedotin) was issued marketing authorization under the
NOC/c policy based on results from a single-arm, phase II pivotal trial in HL
patients with relapsed or refractory disease following an ASCT and a
single-arm, phase II pivotal trial in relapsed or refractory sALCL patients.
ADCETRIS is administered in hospitals through IV infusion over 30 minutes
every three weeks and patients who achieve stable disease or better should
receive a minimum of 8 cycles and up to a maximum of 16 cycles (approximately
one year).

ADCETRIS is the first in a new class of antibody-drug conjugates (ADCs) to be
approved in Canada. Using Seattle Genetics’ proprietary technology, the ADC
consists of a monoclonal antibody directed to an antigen called CD30. The
monoclonal antibody is connected to a cell-killing agent by a linker system
that is designed to be stable in the bloodstream but to release the
cell-killing agent into CD30-expressing cells, resulting in target cell death.
The CD30 antigen is known to be expressed on the Reed-Sternberg cells of HL
and on sALCL, an aggressive type of T-cell non-Hodgkin lymphoma.

“Health Canada’s approval of ADCETRIS is the first step in getting patients
access to this important therapy,” said Sue Robson, Executive Director of
Lymphoma Foundation Canada. “The Lymphoma Foundation is committed to working
with Canada provincial governments to ensure that appropriate patients have
access to this new therapy.”

About 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. The Reed-Sternberg cell generally expresses CD30.
Systemic ALCL is an aggressive type of T-cell non-Hodgkin lymphoma that also
expresses CD30.

According to a report published by the Cancer Advocacy Coalition of Canada,
lymphoma is the most common blood cancer, the sixth most common cause of
cancer death, and the most common cancer for young people under 30 years of
age in Canada. Although primary treatment with front-line combination
chemotherapy can result in durable response rates, up to 30 percent of Hodgkin
lymphoma and over 50 percent of systemic ALCL patients relapse or are
refractory to front-line treatment and have few therapeutic options beyond
ASCT.

About ADCETRIS

ADCETRIS received accelerated approval from the U.S. Food and Drug
Administration (FDA) in August 2011 and was granted conditional marketing
authorization by the European Commission in October 2012 and by Health Canada
in February 2013 for relapsed Hodgkin lymphoma and systemic anaplastic large
cell lymphoma.

ADCETRIS is being evaluated across many disease settings in ongoing clinical
trials in Canada, including a planned phase I/II investigator-sponsored
clinical trial evaluating ADCETRIS in combination with bendamustine for
patients with HL and ALCL that has either relapsed or did not respond to
initial treatment. ADCETRIS is not currently approved for use in combination
with bendamustine for patients with HL and ALCL that has either relapsed or
did not respond to initial treatment.

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.

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. The company’s lead program, ADCETRIS (brentuximab vedotin), received
accelerated approval from the U.S. Food and Drug Administration in August 2011
for two indications. In addition, under a collaboration with Millennium: The
Takeda Oncology Company, ADCETRIS received conditional approval from the
European Commission in October 2012. Seattle Genetics also has three other
clinical-stage antibody-drug conjugate (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 www.seattlegenetics.com.

Certain of the statements made in this press release are forward looking, such
as those, among others, relating to additional approvals of, reimbursement for
and of the potential of clinical trials of ADCETRIS. 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 additional trials and the risk of
adverse events as ADCETRIS advances in clinical trials or as a marketed
product. 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, 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.

Contact:

Seattle Genetics, Inc.
Investors:
Peggy Pinkston, +1-425-527-4160
ppinkston@seagen.com
or
Media:
Tricia Larson, +1-425-527-4180
tlarson@seagen.com
or
Canada PR Agency:
Jennifer Spencer, Thornley Fallis, 416-515-7517 ext. 348
spencer@thornleyfallis.ca