Seattle Genetics, Inc. (Nasdaq: SGEN) today highlighted the company’s broad presence at the upcoming 106th Annual Meeting of the American Association for Cancer Research (AACR) being held April 18 to 22, 2015 in Philadelphia, PA, including eight abstracts on antibody-drug conjugate (ADC) technology and first preclinical data from a new immuno-oncology antibody utilizing sugar-engineered antibody (SEA) technology. Preclinical abstracts accepted for presentation include data in support of SGN-CD19A and SGN-CD70A, and activation of immune cells by SEA-CD40 and ADCETRIS (brentuximab vedotin). In addition, multiple presentations will be featured in Special Sessions and Symposia by Seattle Genetics’ leadership team on the critical role of ADCs in the current and future cancer treatment landscape. Finally, SGN-CD33A will be featured in the “New Drugs on the Horizon” session, focusing on the preclinical rationale and early clinical data for this first-in-class ADC incorporating Seattle Genetics’ newest pyrrolobenzodiazepine (PBD) dimer technology.

“Seattle Genetics has an impressive collection of new data at AACR, demonstrating continued leadership in the field of ADC therapeutics. Abstracts and presentations cover five clinical-stage programs, demonstrating novel preclinical combination regimens, mechanisms of action and advances in ADC technology,” said Jonathan Drachman, M.D., Chief Medical Officer and Executive Vice President, Research and Development at Seattle Genetics. “We are also now building on our expertise in empowered antibodies by initiating phase 1 clinical development of SEA-CD40, a novel CD40-directed immuno-oncology agent. Finally, we will present data on immunogenic cell death caused by ADCETRIS in vitro, providing further rationale for two planned clinical trials in combination with nivolumab under our recently announced collaboration with Bristol Myers Squibb.”

ADCs are monoclonal antibodies designed to selectively deliver cytotoxic agents to tumor cells. With over seventeen years of experience and knowledge in ADC innovation, Seattle Genetics has developed proprietary technology employing synthetic cytotoxic agents and stable linker systems that attach these cytotoxic agents to the antibody. Seattle Genetics’ linker systems are designed to be stable in the bloodstream and release the potent cell-killing agent once inside targeted cancer cells. This approach is intended to spare non-targeted cells and thus reduce many of the toxic effects of traditional chemotherapy while enhancing antitumor activity.

Seattle Genetics is developing a novel approach called SEA technology which is designed to increase the potency of monoclonal antibodies. SEA technology produces a non-fucosylated monoclonal antibody, resulting in an enhanced innate immune response. SEA-CD40 represents the first clinical antibody employing SEA technology. Enhanced binding to effector cells results in better crosslinking and activation of CD40 signaling in immune cells. This stimulation of the patient’s own immune cells has the potential to result in antitumor activity.

Multiple corporate and executive presentations are being featured at AACR. Abstracts can be found at www.aacr.org and include the following:

Advances with ADC Pipeline, Research Programs and Technology

Six presentations will highlight advances with Seattle Genetics’ proprietary ADC pipeline programs, research programs and technology, including:

  • SGN-CD70A will be highlighted in an oral presentation at 4:50 p.m. ET on Sunday, April 19, 2015 (Abstract #946) focusing on the mechanism of the highly potent PBD dimer to induce irreversible DNA damage and disrupt cell cycle progression in tumor cells.
  • A poster presentation on Monday, April 20, 2015 (Abstract #1686) will focus on the target characteristics of CD70 in both aggressive non-Hodgkin lymphomas as well as clear cell renal cell carcinoma. SGN-CD70A is in a phase 1 trial for both of these tumor types.
  • SGN-CD19A will be featured in two poster presentations on Monday, April 20, 2015 (Abstracts #1339 and #2541), illustrating its preclinical activity in combination with standard-of-care agents for acute lymphoblastic leukemia and non-Hodgkin lymphoma. SGN-CD19A is a CD19-directed ADC that incorporates the synthetic cytotoxic cell-killing agent, monomethyl auristatin F (MMAF). During 2015, Seattle Genetics plans to initiate a randomized phase 2 trial of SGN-CD19A in relapsed diffuse large B-cell lymphoma.
  • On Sunday, April 19, 2015, data will be presented in a poster presentation from a novel monomethyl auristatin E drug-linker that has been developed to improve chemical and pharmacokinetic stability resulting in enhanced potency and tolerability in preclinical models (Abstract #648).
  • On Wednesday, April 22, 2015, a poster presentation will focus on the impact of bystander cytotoxic activity of multiple agents, including novel data demonstrating the potent activity of ADCs with the PBD dimer technology (Abstract #5507).

Immuno-Oncology Presentations

  • SEA-CD40 is a novel agonistic CD40-directed antibody. Preclinical data will be presented highlighting increased cytokine production, activation of antigen-presenting cells and stimulation of antigen specific T-cell responses. This immune activity was observed in peripheral blood mononuclear cells from normal donors exposed to an influenza antigen and from patients with melanoma, pancreatic or breast cancer exposed to tumor-associated antigens. The poster entitled “SEA-CD40, a sugar engineered non-fucosylated anti-CD40 antibody with improved immune activating capabilities” will be presented on Monday, April 20, 2015 (Abstract #2472).
  • For the first time, data will be presented demonstrating that brentuximab vedotin (ADCETRIS) induces Immunogenic Cell Death (ICD), a pattern of cytotoxicity associated with activating immune responses within the tumor microenvironment. In evaluating CD30-positive Hodgkin lymphoma tumor cell lines treated with brentuximab vedotin, data demonstrate an ER stress response characterized by display of calreticulin and HSP70 on the surface of brentuximab vedotin-treated lymphoma cells and activation of dendritic cells. These data provide rationale for combining brentuximab vedotin with immuno-oncology agents, such as nivolumab, to maximize cancer cell death and provide a favorable environment for immune activation within the tumor milieu. As part of a collaboration between Seattle Genetics and Bristol Myers Squibb, two clinical trials are planned for initiation in 2015 to evaluate brentuximab vedotin in combination with nivolumab in relapsed Hodgkin lymphoma and relapsed CD30-positive non-Hodgkin lymphoma. The poster entitled “Brentuximab vedotin-mediated immunogenic cell death” will be presented on Monday, April 20, 2015 (Abstract #2469).

Senior Management Presentations

AACR selected members of Seattle Genetics’ leadership team to present in several sessions on the integral role of ADCs in targeted therapy, including:

  • Peter Senter, Ph.D., Vice President, Chemistry and Distinguished Fellow, will chair and present in an educational session titled “From Chemistry to the Clinic: Pathways for Drug Discovery and Development, Part 2: Discovery and Development of Potent Drug Conjugates: From Basic Principles to Clinically Approved Drugs” at 11:45 a.m. ET on Saturday, April 18, 2015;
  • Dana Kennedy, Pharm.D., Executive Medical Director, will summarize preclinical and interim phase 1 SGN-CD33A data in a session titled “Drug Development Track: Special Session New Drugs on the Horizon 2” at 4:45 p.m. ET on Sunday, April 19, 2015 (Abstract #DDT02-04). The presentation will include patient case studies representing three potential SGN-CD33A development paths, including as a monotherapy, as a bridge to transplant or in combination with hypomethylating agents;
  • Clay Siegall, Ph.D., President and Chief Executive Officer, will present during a session titled “Novel Delivery Systems and/or Formulations in Cancer Treatment: Recent Advances in Diagnostics and Therapeutics Research” at 2: 15 p.m. ET on Monday, April 20, 2015; and
  • Jonathan Drachman, M.D., Chief Medical Officer and Executive Vice President, Research and Development, will chair and present in a major symposium titled “Empowering Antibodies to Fight Cancer: ADCs and Immunoconjugates” at 1:00 p.m. ET on Tuesday, April 21, 2015.

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 a CD30-targeted ADC that, in collaboration with Takeda Pharmaceutical Company Limited, is commercially available for two indications in more than 50 countries, including the U.S., Canada, Japan and members of the European Union. Additionally, ADCETRIS is being evaluated broadly in more than 30 ongoing clinical trials in CD30-expressing malignancies. Seattle Genetics is also advancing a robust pipeline of clinical-stage programs, including SGN-CD19A, SGN-CD33A, SGN-LIV1A, SGN-CD70A, ASG-22ME, ASG-15ME and SEA-CD40. 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.

Forward Looking Statement

Certain of the statements made in this press release are forward looking, such as those, among others, relating to future development activities including clinical trials and the therapeutic potential of ADCETRIS and our product candidates. 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 lack of efficacy or risk of adverse events as these product candidates advance in development. More information about the risks and uncertainties faced by Seattle Genetics is contained in the company’s Annual Report on Form 10-K for the year ended December 31, 2014 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.