Seattle Genetics to Present Data from Broad ADCETRIS® (Brentuximab Vedotin) Development Program at ASH 2017

-Positive Phase 3 ECHELON-1 Clinical Trial Results to be Featured in the Plenary Scientific Session on Sunday, December 10^th-

-Eighteen ADCETRIS Data Presentations Support Broad Clinical Development Efforts to Establish ADCETRIS as the Foundation of Care for CD30-Expressing Lymphomas-

Seattle Genetics, Inc. SGEN today announced that 18 abstracts featuring data from the broad ADCETRIS (brentuximab vedotin) development program have been accepted for presentation, including a plenary presentation, at the 58^th American Society of Hematology (ASH) Annual Meeting and Exposition taking place from December 9-12, 2017 in Atlanta, Georgia. ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30, which is expressed on the surface of Hodgkin lymphoma cells and several types of non-Hodgkin lymphoma. ADCETRIS is being evaluated globally as the foundation of care for CD30-expressing lymphomas in more than 70 corporate- and investigator-sponsored clinical trials.

Data accepted for presentation at the ASH Annual Meeting include the following:

• Data from the phase 3 ECHELON-1 clinical trial evaluating ADCETRIS in combination with chemotherapy in frontline advanced classical Hodgkin lymphoma patients will be featured in the Plenary Scientific Session on Sunday, December 10, 2017 from 2:00 – 4:00 p.m. ET. Based on the positive results from the ECHELON-1 trial, the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy Designation to ADCETRIS in combination with chemotherapy for the frontline treatment of patients with advanced classical Hodgkin lymphoma. Seattle Genetics expects to submit in the fourth quarter of 2017 a supplemental Biologics License Application (BLA) to the FDA for approval of ADCETRIS in frontline advanced classical Hodgkin lymphoma.
• Numerous oral and poster presentations highlighting additional progress within the ADCETRIS development program including:
  • Updated durability results from the phase 3 ALCANZA clinical trial in patients with CD30-expressing mycosis fungoides and primary cutaneous anaplastic large cell lymphoma, the most common subtypes of cutaneous T-cell lymphoma (CTCL). Based on the positive results from the ALCANZA trial, a supplemental BLA for ADCETRIS in CTCL was accepted for filing by the FDA. The FDA granted Priority Review for the application and the Prescription Drug User Fee Act (PDUFA) target action date is December 16, 2017. ADCETRIS previously received FDA Breakthrough Therapy Designation in this setting.
  • Updated results from a phase 1/2 study of ADCETRIS in combination with Opdivo (nivolumab) among patients with relapsed or refractory Hodgkin lymphoma
  • Final five-year survival and durability results in patients with CD30-expressing peripheral T-cell lymphomas who received ADCETRIS with cyclophosphamide, hydroxydaunorubicin, and prednisone (CHP) as frontline therapy

"At this year's ASH Annual Meeting, we will present data from 18 abstracts, highlighting several ADCETRIS clinical program advancements that support our plans to establish ADCETRIS as the foundation of care for CD30-expressing lymphomas," said Clay Siegall, Ph.D., President and Chief Executive Officer of Seattle Genetics. "Importantly, the results of the phase 3 ECHELON-1 clinical trial evaluating ADCETRIS combination therapy in frontline advanced Hodgkin lymphoma patients was selected from over 6,000 abstracts submitted to be featured in the Plenary Scientific Session. These data are the basis for our planned supplemental biologics license application to the FDA requesting approval of ADCETRIS in this setting. The breadth of data being presented with ADCETRIS in CD30-expressing lymphomas demonstrates the power of antibody-drug conjugates with a goal of improving patient outcomes."

ADCETRIS is currently not approved for the treatment of frontline Hodgkin lymphoma, CTCL, or as combination therapy for Hodgkin lymphoma or non-Hodgkin lymphoma.

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

Saturday, December 9, 2017

• Updated analyses of the international, open-label, randomized, phase 3 ALCANZA study: longer-term evidence for superiority of brentuximab vedotin versus methotrexate or bexarotene for CD30-positive cutaneous T-cell lymphoma (Abstract #1509, poster presentation)
• A pilot study of weekly brentuximab vedotin in patients with CD30+ malignancies resistant to every 3 week brentuximab vedotin (Abstract #1528, poster presentation)
• Brentuximab vedotin with R-CHP chemotherapy as frontline treatment for patients with CD30 positive primary mediastinal large B-cell, diffuse large B-cell, and grey zone lymphomas: results of a phase I/II multisite trial (Abstract #191, oral presentation at 3:00 p.m. ET)
• Patient-reported distress in Hodgkin lymphoma patients on active therapy vs. long-term survivors (Abstract #2173, poster presentation)
• Real world clinical and economic burden of patients with Hodgkin lymphoma who fail frontline therapy in the US (Abstract #2128, poster presentation)

Sunday, December 10, 2017

• Brentuximab vedotin plus doxorubicin, vinblastine, dacarbazine (A+AVD) as frontline therapy demonstrates superior modified progression-free survival versus ABVD in patients with previously untreated stage III or IV Hodgkin lymphoma (HL): the phase 3 ECHELON-1 study (Plenary Scientific Session presentation from 2:00 – 4:00 p.m. ET)
• Five-year survival results: frontline brentuximab vedotin in combination with CHP in patients with CD30-expressing peripheral T-cell lymphomas (Abstract #2790, poster presentation)
• Radiographic and high-throughput sequencing (HTS)-based response assessment after brentuximab vedotin plus ifosfamide, carboplatin, and etoposide (ICE) for relapsed/refractory classical Hodgkin lymphoma: updated results of a phase I/II trial (Abstract #2806, poster presentation)
• Patient and physician preferences for front-line treatment of advanced stage Hodgkin lymphoma (Abstract #4082, poster presentation)
• Changes in serum TARC predict PET response among pediatric patients with relapsed or refractory Hodgkin lymphoma treated with brentuximab vedotin and gemcitabine: a report from the Children's Oncology Group (Abstract #2798, poster presentation)
• Phase 2 Study of Brentuximab Vedotin in Patients with Advanced Systemic Mastocytosis (Abstract #2909, poster presentation)

Monday, December 11, 2017

• Results from a phase 1/2 study of brentuximab vedotin in combination with nivolumab in patients with relapsed or refractory Hodgkin lymphoma (Abstract #649, oral presentation at 10:30 a.m. ET)
• Sequential brentuximab vedotin before and after adriamycin, vinblastine, and dacarbazine (A-VAD-A) for older patients with untreated Hodgkin lymphoma: final results from a multicenter phase II study (Abstract #733, oral presentation at 2:45 p.m. ET)

About ADCETRIS

ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30 and is being evaluated broadly in more than 70 clinical trials, including four phase 3 studies: the ECHELON-1 trial in frontline classical Hodgkin lymphoma from which positive top-line results were recently reported and the FDA granted Breakthrough Therapy Designation in this setting, the ongoing ECHELON-2 trial in frontline mature T-cell lymphomas, the completed ALCANZA trial in cutaneous T-cell lymphoma that supported the supplemental BLA with a Prescription Drug User Fee Act (PDUFA) target action date of December 16, 2017, and the recently initiated CHECKMATE 812 trial of ADCETRIS in combination with Opdivo (nivolumab) for relapsed/refractory Hodgkin lymphoma.

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 FDA approval 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 in 2013, and non-conditional approval for post-ASCT consolidation treatment of Hodgkin lymphoma patients at increased risk of relapse or progression.

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. The European Commission extended the current conditional marketing authorization 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.

ADCETRIS has received marketing authorization by regulatory authorities in 68 countries for relapsed or refractory Hodgkin lymphoma and sALCL. 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 dedicated to improving the lives of people with cancer through novel antibody-based therapies. 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. Seattle Genetics commercializes ADCETRIS^® (brentuximab vedotin) for the treatment of several types of CD30-expressing lymphomas. The company is also advancing a robust pipeline of novel therapies for solid tumors and blood-related cancers designed to address significant unmet medical needs and improve treatment outcomes for patients. More information can be found at www.seattlegenetics.com and follow @SeattleGenetics on Twitter.

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 ADCETRIS-treated patients.

Contraindication

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

Warnings and Precautions

• Peripheral neuropathy (PN): ADCETRIS causes PN that is predominantly sensory. Cases of motor PN have also been reported. ADCETRIS-induced PN is cumulative. Monitor for symptoms such as hypoesthesia, hyperesthesia, paresthesia, discomfort, a burning sensation, neuropathic pain, or weakness. Institute dose modifications accordingly.
• Anaphylaxis and infusion reactions: Infusion-related reactions (IRR), including anaphylaxis, have occurred with ADCETRIS. Monitor patients during infusion. If an IRR occurs, interrupt the infusion and institute appropriate medical management. If anaphylaxis occurs, immediately and permanently discontinue the infusion and administer appropriate medical therapy. Premedicate patients with a prior IRR before 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 ADCETRIS dose. 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 ADCETRIS-treated patients. Closely monitor patients during treatment for 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 use 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 use in patients with moderate or severe hepatic impairment.
• Hepatotoxicity: Serious cases, including fatal outcomes, have occurred in ADCETRIS-treated patients. Cases were consistent with hepatocellular injury, including elevations of transaminases and/or bilirubin, and occurred after the first ADCETRIS dose or rechallenge. Preexisting liver disease, elevated baseline liver enzymes, and concomitant medications may increase the risk. Monitor liver enzymes and bilirubin. Patients with new, worsening, or recurrent hepatotoxicity may require a delay, change in dose, or discontinuation of ADCETRIS.
• 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. Other possible contributory factors other than ADCETRIS include prior therapies and underlying disease that may cause immunosuppression. Consider PML diagnosis in patients 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: Noninfectious pulmonary toxicity events including pneumonitis, interstitial lung disease, and acute respiratory distress syndrome, some with fatal outcomes, have been reported. Monitor patients for signs and symptoms, 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: Acute pancreatitis, including fatal outcomes, has been reported in ADCETRIS-treated patients. Other 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 animal studies, ADCETRIS can cause fetal harm. Advise females of reproductive potential of the potential risk to the fetus, and to avoid pregnancy during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Most Common (≥20%) Adverse Reactions: peripheral sensory neuropathy, fatigue, nausea, diarrhea, neutropenia, upper respiratory tract infection, and pyrexia.

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

Moderate or severe hepatic impairment or severe renal impairment: MMAE exposure and adverse reactions are increased. Avoid use.

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

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 the therapeutic and commercial potential of ADCETRIS, potential development and regulatory activities including the intended submission of a supplemental biologics license application to the FDA for use in frontline Hodgkin lymphoma, the potential approval of ADCETRIS for use in CTCL by the PDUFA target action date, future clinical trials and regulatory submissions, upcoming presentations and publications, and potential uses of the product candidates, as well as other statements that are not historical facts. 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 risk that there could be a delay in our planned regulatory submissions or expected approvals in each case for a variety of reasons, including the difficulty and uncertainty of pharmaceutical product development and unexpected adverse events or regulatory action. We may also be unable to expand ADCETRIS' labeled indications due to unexpected data from our clinical trials or regulatory action. 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, 2017 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.

View source version on businesswire.com: http://www.businesswire.com/news/home/20171101005490/en/