Seattle Genetics Demonstrates Commitment To Improve Hodgkin Lymphoma Treatment Paradigm Through Multiple ADCETRIS (Brentuximab Vedotin) Data Presentations At ISHL 2016

-ADCETRIS Data Featured in 21 Presentations Broadly Across HL Disease Settings-

-Data from Multiple Presentations Support Goal to Establish ADCETRIS as the Foundation of Care for classical HL-

BOTHELL, Wash.--(BUSINESS WIRE)--Seattle Genetics, Inc. (Nasdaq: SGEN) today highlighted multiple data presentations at the 10^th International Symposium on Hodgkin Lymphoma (ISHL) taking place in Cologne, Germany, October 22-25, 2016, evaluating ADCETRIS (brentuximab vedotin) across a broad range of Hodgkin lymphoma (HL) disease settings. ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30, a defining marker of classical HL that plays a role in tumor pathogenesis. ADCETRIS is being evaluated globally as the foundation of therapy for HL in more than 45 ongoing corporate- and investigator-sponsored clinical trials.

“For more than a decade, we have been committed to improving treatment outcomes for classical HL patients. We have made tremendous progress with ADCETRIS, which is now FDA-approved for two HL indications in the U.S. and Europe and is being evaluated broadly across all lines of therapy and in many novel regimens,” said Jonathan Drachman, M.D., Chief Medical Officer and Executive Vice President, Research and Development at Seattle Genetics. “The data presented at ISHL continue to advance our goal of establishing ADCETRIS as the foundation of care for HL. With 21 abstracts accepted for presentation, we, along with our partner Takeda, are pleased to share new and updated data with the scientific community at ISHL to help move the field forward.”

Data presented at ISHL include an update of the progression-free survival and safety from the phase 3 AETHERA trial approximately four years since the last patient was enrolled, demonstrating sustained progression-free survival benefit after extended observation. In addition, updates will be presented from trials evaluating ADCETRIS as both mono- and combination therapy in frontline HL patients age 60 and older, and as second-line therapy for relapsed or refractory HL. Lastly, preclinical data will be presented indicating additional potential mechanisms of action for ADCETRIS, including immunogenic cell death, supporting evaluation of combination therapy with immuno-oncology agents.

Multiple corporate and investigator presentations will be featured at ISHL. Abstracts can be found at www.hodgkinsymposium.org and include the following:

• Immune Systems Engagement Results in Non-Classical Antibody-Drug Conjugate Antitumor Activity of Brentuximab Vedotin (Abstract #P099, poster presentation)
• Evaluation of Serum TARC Levels in Patients at Risk of Progression Following Autologous Stem Cell Transplant for Hodgkin Lymphoma: Results from the AETHERA Trial (Abstract #P060, poster presentation)
• Brentuximab Vedotin After Autologous Stem Cell Transplant Yields the Strongest Benefit in Hodgkin lymphoma Patients with = 2 Risk Factors: Results of a Multivariate Analysis (Abstract #P089 , poster presentation)
• Brentuximab Vedotin Alone and in Combination With Dacarbazine or Bendamustine in Patients Aged =60 Years With Newly Diagnosed Hodgkin Lymphoma: Interim Results of a Phase 2 Study (Abstract #P023, poster presentation)
• Brentuximab Vedotin Plus Bendamustine as a Salvage Treatment Regimen for Patients with Relapsed or Refractory Hodgkin Lymphoma (Abstract #P082, poster presentation)
• PET Adapted Dose Escalation of Brentuximab Vedotin as First Line Salvage Therapy in Relapse/Refractory HL (Abstract #P083, poster presentation)
• Post Transplant Outcomes in a Multicenter Phase II Study of Brentuximab Vedotin as First Line Salvage Therapy in Relapsed/Refractory HL Prior to ASCT (Abstract #P086, poster presentation)
• Pharmacokinetics, Immunogenicity and Safety of Weekly Dosing of Brentuximab Vedotin in Pediatric Patients with Hodgkin Lymphoma (Abstract #P067, oral presentation)
• A Phase I Study with an Expansion Cohort of the Combination of Ipilimumab and Brentuximab Vedotin in Patients with Relapsed/Refractory Hodgkin Lymphoma: A trial of the ECOG-ACRIN Cancer Research Group (Abstract #P080, poster presentation)
• The Pharmacokinetic and Pharmacodynamic Properties of Brentuximab Vedotin in a Patient Undergoing Hemodialysis (Abstract #P098, poster presentation)
• Single-Arm Study of Brentuximab Vedotin in Patients with Relapsed or Refractory Hodgkin lymphoma who are Ineligible for Stem Cell Transplantation or Multiagent Chemotherapy (Abstract #P104, poster presentation)
• Combining Brentuximab Vedotin with DHAP as Salvage Treatment in Relapsed/Refractory Hodgkin lymphoma: a Phase 1 Dose-Escalation study (Abstract #T024, oral presentation)
• Preliminary Results of a Phase II Study of Brentuximab Vedotin Using a Response Adapted Design in the First Line Treatment of Patients with Hodgkin lymphoma Unsuitable for Chemotherapy Due to Age, Frailty or Co-morbidity (BREVITY) (Abstract #P002, poster presentation)
• Real-World Effectiveness of Brentuximab Vedotin vs. Other Treatments in Patients with Relapsed/Refractory Hodgkin Lymphoma post Autologous Stem-Cell Transplantation (Abstract #P094, poster presentation)
• Brentuximab Vedotin in Patients who are Ineligible for Autologous Stem Cell Transplant with Relapsed or Refractory Hodgkin Lymphoma: A UK and Germany Retrospective Study (Abstract #P093, poster presentation)
• Risk Factors for Relapse in Patients with Relapsed or Refractory Hodgkin Lymphoma after Autologous Stem Cell Transplant: A Real-World Analysis in Germany and the United Kingdom (Abstract #P095, poster presentation)
• Superiority of Modified Progression Free Survival to Evaluate Chemotherapy Effectiveness for Advanced Stage Hodgkin Lymphoma (Abstract #P007, poster presentation)
• Sequential Brentuximab Vedotin and Adriamycin, Vinblastine and Darabazine (AVD) for Older Patients with Untreated Hodgkin Lymphoma: Findings from a Phase II Window study (Abstracts #P001, poster presentation)
• PET-adapted Therapy with Brentuximab Vedotin and Augmented ICE for Relapsed/Refractory Hodgkin Lymphoma – Lack of Improvement with 3 versus 2 Cycles of Weekly BV (Abstract #P088, poster presentation)
• An International Multicenter Phase I/II Study of Brentuximab Vedotin and Bendamustine in Patients with Heavily Treated Relapsed or Refractory Hodgkin Lymphoma and Anaplastic Large T-Cell Lymphoma (Abstract #P085, poster presentation)
• HALO Study: a Phase 1/2 Clinical Trial of Brentuximab Vedotin and Bendamustine in Elderly Patients with Previously Untreated Advanced Hodgkin Lymphoma (Abstract #P011, poster presentation)

ADCETRIS is currently not approved for the treatment of frontline or salvage HL in patients eligible for autologous transplant, graft-versus-host disease (GVHD) or as a combination therapy for HL.

About Classical Hodgkin Lymphoma

Lymphoma is a general term for a group of cancers that originate in the lymphatic system and is the most common type of blood cancer. There are two major categories of lymphoma: HL and non-Hodgkin lymphoma. Classical HL is distinguished from other lymphomas by the characteristic presence of CD30-positive Reed-Sternberg cells.

According to the American Cancer Society, approximately 8,500 cases of HL will be diagnosed in the United States during 2016 and more than 1,100 will die from the disease. According to the Lymphoma Coalition, over 62,000 people worldwide are diagnosed with HL each year and approximately 25,000 people die each year from this cancer.

About ADCETRIS

ADCETRIS is being evaluated broadly in more than 70 ongoing clinical trials, including two phase 3 studies, ECHELON-1 in frontline classical HL and ECHELON-2 in frontline mature T-cell lymphomas, as well as trials in many additional types of CD30-expressing malignancies, including B-cell lymphomas.

ADCETRIS 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 has received approval from the FDA for three indications: (1) regular approval for the treatment of patients with classical Hodgkin lymphoma after failure of autologous hematopoietic stem cell transplantation (auto-HSCT) or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not auto-HSCT candidates, (2) regular approval for the treatment of classical Hodgkin lymphoma patients at high risk of relapse or progression as post-auto-HSCT consolidation, and (3) accelerated approval for the treatment of patients with systemic anaplastic large cell lymphoma (sALCL) after failure of at least one prior multi-agent chemotherapy regimen. The sALCL indication is approved under accelerated approval based on overall response rate. Continued approval for the sALCL indication may be contingent upon verification and description of clinical benefit in confirmatory trials. Health Canada granted ADCETRIS approval with conditions for relapsed or refractory Hodgkin lymphoma and sALCL.

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 Hodgkin lymphoma 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 65 countries.

In June 2016, the European Commission extended the current conditional approval of ADCETRIS and approved ADCETRIS for the treatment of adult patients with CD30-positive Hodgkin lymphoma at increased risk of relapse or progression following ASCT. 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 is solely responsible for development costs.

About Seattle Genetics

Seattle Genetics is an innovative biotechnology company that develops and commercializes novel antibody-based therapies for the treatment of cancer. The company’s industry-leading antibody-drug conjugate (ADC) technology harnesses the targeting ability of antibodies to deliver cell-killing agents directly to cancer cells. ADCETRIS^® (brentuximab vedotin), the company’s lead product, in collaboration with Takeda Pharmaceutical Company Limited, is the first in a new class of ADCs commercially available globally in 65 countries for relapsed classical Hodgkin lymphoma (HL) and relapsed systemic anaplastic large cell lymphoma (sALCL). Seattle Genetics is also advancing vadastuximab talirine (SGN-CD33A; 33A), an ADC in a phase 3 trial for acute myeloid leukemia. Headquartered in Bothell, Washington, Seattle Genetics has a robust pipeline of innovative therapies for blood-related cancers and solid tumors designed to address significant unmet medical needs and improve treatment outcomes for patients. The company has collaborations for its proprietary ADC technology with a number of companies including AbbVie, Astellas, Bayer, Celldex, Genentech, GlaxoSmithKline and Pfizer. More information can be found at www.seattlegenetics.com

ADCETRIS (brentuximab vedotin) 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

ADCETRIS is contraindicated with concomitant bleomycin due to pulmonary toxicity (e.g., interstitial infiltration and/or inflammation).

Warnings and Precautions

• Peripheral neuropathy (PN): ADCETRIS treatment causes a PN that is predominantly sensory. Cases of motor PN have also been reported. ADCETRIS-induced PN 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.
• Anaphylaxis and infusion reactions: Infusion-related reactions, including anaphylaxis, have occurred with ADCETRIS. Monitor patients during infusion. If an infusion-related reaction occurs, interrupt the infusion and institute appropriate medical management. If anaphylaxis occurs, immediately and permanently discontinue the infusion and administer appropriate medical therapy. Patients who experienced a prior infusion-related reaction should be premedicated for subsequent infusions. Premedication may include acetaminophen, an antihistamine, and a corticosteroid.
• Hematologic toxicities: Prolonged (=1 week) severe neutropenia and Grade 3 or 4 thrombocytopenia or anemia 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. Monitor patients for fever. If Grade 3 or 4 neutropenia develops, consider dose delays, reductions, discontinuation, or G-CSF prophylaxis with subsequent doses.
• Serious infections and opportunistic infections: Infections such as pneumonia, bacteremia, and sepsis or 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.
• Increased toxicity in the presence of severe renal impairment: The frequency of =Grade 3 adverse reactions and deaths was greater in patients with severe renal impairment compared to patients with normal renal function. Avoid the use of ADCETRIS in patients with severe renal impairment.
• Increased toxicity in the presence of moderate or severe hepatic impairment: The frequency of =Grade 3 adverse reactions and deaths was greater in patients with moderate or severe hepatic impairment compared to patients with normal hepatic function. Avoid the use of ADCETRIS in patients with moderate or severe hepatic impairment.
• Hepatotoxicity: Serious cases of hepatotoxicity, including fatal outcomes, have occurred with ADCETRIS. Cases were consistent with hepatocellular injury, including elevations of transaminases and/or bilirubin, and occurred after the first dose of ADCETRIS or rechallenge. Preexisting liver disease, elevated baseline liver enzymes, and concomitant medications may also increase the risk. Monitor liver enzymes and bilirubin. Patients experiencing new, worsening, or recurrent hepatotoxicity may require a delay, change in dose, or discontinuation of ADCETRIS.
• Progressive multifocal leukoencephalopathy (PML): JC virus infection resulting in PML and death has been reported in ADCETRIS-treated patients. First onset of symptoms occurred at various times from initiation of ADCETRIS therapy, with some cases occurring within 3 months of initial exposure. 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. Hold ADCETRIS if PML is suspected and discontinue ADCETRIS if PML is confirmed.
• Pulmonary toxicity: Events of noninfectious pulmonary toxicity including pneumonitis, interstitial lung disease, and acute respiratory distress syndrome, some with fatal outcomes, have been reported. Monitor patients for signs and symptoms of pulmonary toxicity, including cough and dyspnea. In the event of new or worsening pulmonary symptoms, hold ADCETRIS dosing during evaluation and until symptomatic improvement.
• Serious dermatologic reactions: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), including fatal outcomes, have been reported with ADCETRIS. If SJS or TEN occurs, discontinue ADCETRIS and administer appropriate medical therapy.
• Gastrointestinal (GI) complications: Fatal and serious GI complications, including perforation, hemorrhage, erosion, ulcer, intestinal obstruction, enterocolitis, neutropenic colitis, and ileus have been reported in ADCETRIS-treated patients. Lymphoma with preexisting GI involvement may increase the risk of perforation. In the event of new or worsening GI symptoms, perform a prompt diagnostic evaluation and treat appropriately.
• Embryo-fetal toxicity: Based on the mechanism of action and findings in animals, ADCETRIS can cause fetal harm when administered to a pregnant woman. Females of reproductive potential should avoid pregnancy during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Adverse Reactions

In two uncontrolled single-arm trials of ADCETRIS as monotherapy in 160 patients with relapsed classical HL and sALCL, 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.

In a placebo-controlled trial of ADCETRIS in 329 patients with classical HL at high risk of relapse or progression post-auto-HSCT, the most common adverse reactions (=20%) in the ADCETRIS-treatment arm (167 patients), regardless of causality, were: neutropenia, peripheral sensory neuropathy, thrombocytopenia, anemia, upper respiratory tract infection, fatigue, peripheral motor neuropathy, nausea, cough, and diarrhea.

Drug Interactions

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

Use in Specific Populations

MMAE exposure and adverse reactions are increased in patients with moderate or severe hepatic impairment or severe renal impairment. Avoid use.

Advise females of reproductive potential to avoid pregnancy during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Advise males with female sexual partners of reproductive potential to use effective contraception during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Advise patients to report pregnancy immediately and avoid breastfeeding while receiving ADCETRIS.

For additional Important Safety Information, including Boxed WARNING, please see the full Prescribing Information for ADCETRIS at www.seattlegenetics.com or www.ADCETRIS.com.

Forward-Looking Statement:

Certain of the statements made in this press release are forward looking, such as those, among others, relating to our goal of establishing ADCETRIS as the foundation of care for HL, the therapeutic and commercial potential of ADCETRIS, including the anticipated benefits of Seattle Genetics’ ADCETRIS clinical development program and possible mechanisms of action for 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 risks of adverse events associated with ADCETRIS use, negative or unexpected ADCETRIS clinical trial results even after promising results in earlier company- and investigator-sponsored trials, and adverse regulatory actions affecting ADCETRIS, all of which could result in Seattle Genetics being unable to expand ADCETRIS’ labeled indications of use in other settings. Seattle Genetics may also experience delays in the conduct of and obtaining data from clinical trials for a variety of reasons, including the inherent difficulty and uncertainty of pharmaceutical product development. More information about the risks and uncertainties faced by Seattle Genetics is contained under the caption “Risk Factors” included in the company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2016 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.