Seattle Genetics Highlights ADCETRIS® (Brentuximab Vedotin) Phase 2 Clinical Data in Diffuse Large B-cell Lymphoma (DLBCL) at ASH 2013

-42 Percent Objective Response Rate in Relapsed or Refractory DLBCL, the Most Common Subtype of Non-Hodgkin Lymphoma-

-11.5 Month Median Duration Among DLBCL Patients who Achieved Complete Remission-

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NEW ORLEANS--(BUSINESS WIRE)--

Seattle Genetics, Inc. (SGEN) today announced updated results from a phase 2 clinical trial of ADCETRIS (brentuximab vedotin) in diffuse large B-cell lymphoma (DLBCL) and other B-cell non-Hodgkin lymphomas. The data, which demonstrated an encouraging activity and tolerability profile in the relapsed and refractory setting, were presented in an oral presentation at the 55th American Society of Hematology (ASH) Annual Meeting and Exposition taking place in New Orleans, Louisiana, December 7-10, 2013. ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30. ADCETRIS is currently not approved for the treatment of DLBCL or other B-cell lymphomas.

“In DLBCL, patients with relapsed or refractory disease have poor outcomes, and there is a significant need for better therapeutic approaches to treat this aggressive non-Hodgkin lymphoma subtype,” said Jonathan Drachman, M.D., Chief Medical Officer and Executive Vice President, Research and Development at Seattle Genetics. “We are encouraged by the interim phase 2 results which demonstrated that single-agent ADCETRIS induced a 42 percent objective response rate and manageable safety profile among advanced DLBCL patients, including a high percentage whose disease was refractory to their prior therapy. Based on these data, we have expanded our clinical program for ADCETRIS in DLBCL both as a single-agent and in combination with standard regimens for both relapsed and newly diagnosed patients.”

A Phase 2 Study of Brentuximab Vedotin in Patients with Relapsed or Refractory CD30-Positive Non-Hodgkin Lymphomas: Interim Results in Patients with DLBCL and Other B-cell Lymphomas (Abstract #848)

Interim data from an ongoing phase 2 clinical trial were reported from 50 patients with DLBCL and 18 patients with other B-cell lymphomas. Among the DLBCL patients, the median age was 63 years, 74 percent were refractory to frontline therapy and 82 percent were refractory to their most recent prior therapy. Patients were treated with single-agent ADCETRIS every three weeks. The trial was designed to assess the antitumor activity, duration of response and safety profile of ADCETRIS in these patients. Key findings presented by Dr. Nancy Bartlett from the Washington University, Siteman Cancer Center in St. Louis, MO, included:

  • Of the 50 patients with DLBCL, 42 percent achieved an objective response, including 16 percent complete remissions and 26 percent partial remissions.
  • At the time of data analysis, the median duration of response for DLBCL was 5.8 months. For DLBCL patients who achieved a complete remission, the median duration of response was 11.5 months.
  • Objective responses were observed across a broad range of CD30 expression, from DLBCL patients with undetectable CD30 by standard immunohistochemistry testing to those with CD30 expression up to 90 percent.
  • The most common treatment-emergent adverse events of any grade in patients with DLBCL and other B-cell lymphomas occurring in more than 25 percent of all patients enrolled were fatigue (49 percent), neutropenia (40 percent), nausea (38 percent), diarrhea (37 percent) and fever (29 percent).
  • The most common Grade 3 treatment-emergent adverse events in patients with DLBCL and other B-cell lymphomas were neutropenia and anemia. The only Grade 4 treatment-emergent event was neutropenia. Serious adverse events considered related to treatment and occurring in more than one patient were pneumonia (three patients) and anemia, febrile neutropenia, neutropenia and thrombocytopenia (two patients each).

These encouraging findings support Seattle Genetics’ ongoing evaluation of ADCETRIS as a treatment for DLBCL. The phase 2 clinical trial presented at ASH has been expanded to include a treatment arm to assess the activity and tolerability of ADCETRIS in combination with Rituxan (rituximab) as well as an arm to evaluate single-agent ADCETRIS in patients with undetectable CD30 expression using standard immunohistochemistry methods. In addition, a phase 2 trial was recently initiated to evaluate ADCETRIS plus R-CHOP in newly diagnosed, high-risk DLBCL patients, regardless of CD30 expression level. More information about these ongoing phase 2 DLBCL clinical trials, including enrolling centers, is available by visiting www.clinicaltrials.gov.

About Diffuse Large B-Cell 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. Non-Hodgkin lymphoma represents a diverse group of cancers that develop in the lymphatic system and are characterized by uncontrolled growth and accumulation of abnormal lymphocytes. Lymphocytes are a type of blood cells that are responsible for defending the body against infection. The most common forms of non-Hodgkin lymphoma are diffuse large B-cell lymphoma (an aggressive subtype) and follicular lymphoma (an indolent subtype).

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.

ADCETRIS for intravenous injection received accelerated approval from the U.S. Food and Drug Administration (FDA) and approval with conditions from Health Canada 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 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.

ADCETRIS was granted conditional marketing authorization by the European Commission in October 2012 for two indications: (1) for the treatment of adult patients with relapsed or refractory CD30-positive HL following autologous stem cell transplant (ASCT), or following at least two prior therapies when ASCT or multi-agent chemotherapy is not a treatment option, and (2) the treatment of adult patients with relapsed or refractory sALCL. ADCETRIS has received marketing authorization by regulatory authorities in more than 35 countries. See important safety information below.

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

About Seattle Genetics

Seattle Genetics is a biotechnology company focused on the development and commercialization of innovative antibody-based therapies for the treatment of cancer. Seattle Genetics is leading the field in developing antibody-drug conjugates (ADCs), a technology designed to harness the targeting ability of antibodies to deliver cell-killing agents directly to cancer cells. The company’s lead product, ADCETRIS® (brentuximab vedotin) is an ADC that, in collaboration with Takeda Pharmaceutical Company Limited, has been approved for two indications in more than 35 countries, including the U.S., European Union and Canada. Additionally, ADCETRIS is being evaluated broadly in more than 20 ongoing clinical trials. Seattle Genetics is also advancing a robust pipeline of clinical-stage ADC programs, including SGN-CD19A, SGN-CD33A, SGN-LIV1A, ASG-22ME and ASG-15ME. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including AbbVie, Agensys (an affiliate of Astellas), Bayer, Genentech, GlaxoSmithKline and Pfizer. More information can be found at www.seattlegenetics.com.

U.S. Important Safety Information

BOXED WARNING

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

Contraindication:

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

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. 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, interrupt the infusion. If anaphylaxis occurs, immediately and permanently discontinue the infusion.
  • Hematologic toxicities: Grade 3 or 4 anemia, thrombocytopenia and prolonged (≥1 week) severe neutropenia can occur with ADCETRIS. Febrile neutropenia has been reported with ADCETRIS. Monitor complete blood counts prior to each dose of ADCETRIS and consider more frequent monitoring for patients with Grade 3 or 4 neutropenia. Closely monitor patients for fever. If Grade 3 or 4 neutropenia develops, manage by G-CSF support, dose delays, reductions or discontinuation.
  • Serious infections and opportunistic infections: Infections such as pneumonia, bacteremia and sepsis/septic shock (including fatal outcomes) have been reported in patients treated with ADCETRIS. Closely monitor patients during treatment for the emergence of possible bacterial, fungal or viral infections.
  • Tumor lysis syndrome: Closely monitor patients with rapidly proliferating tumor and high tumor burden.
  • Progressive multifocal leukoencephalopathy (PML): JC virus infection resulting in PML and death has been reported in ADCETRIS-treated patients. In addition to ADCETRIS therapy, other possible contributory factors include prior therapies and underlying disease that may cause immunosuppression. Consider the diagnosis of PML in any patient presenting with new-onset signs and symptoms of central nervous system abnormalities. Evaluation of PML includes, but is not limited to, consultation with a neurologist, brain MRI, and lumbar puncture or brain biopsy. Hold ADCETRIS if PML is suspected and discontinue ADCETRIS if PML is confirmed.
  • Stevens-Johnson syndrome (SJS): SJS has been reported with ADCETRIS. If SJS occurs, discontinue ADCETRIS and administer appropriate medical therapy.
  • Embryo-fetal toxicity: Fetal harm can occur. Advise pregnant women 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:

Concomitant use of strong CYP3A4 inhibitors or inducers, or P-gp inhibitors, has the potential to affect the exposure to MMAE.

Use in Specific Populations:

MMAE exposure is increased in patients with hepatic impairment and severe renal impairment.

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

Certain of the statements made in this press release are forward-looking, such as those, among others, relating ADCETRIS as a therapy for diffuse large B-cell lymphoma. 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 September 30, 2013 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, 425-527-4160
ppinkston@seagen.com
or
Media:
Tricia Larson, 425-527-4180
tlarson@seagen.com
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