Seattle Genetics Initiates Phase 1 Trial of SGN-CD352A for Patients with Relapsed or Refractory Multiple Myeloma

-SGN-CD352A, a Novel Antibody-Drug Conjugate (ADC), Represents Seattle Genetics’ 9th Clinical Stage Program in a Robust Pipeline of Empowered Antibody Therapies-

-Preclinical Data Showing Potent Antitumor Activity of SGN-CD352A in B-cell Cancers Presented at the 2016 American Association of Cancer Research Annual Meeting-

BOTHELL, Wash.--()--Seattle Genetics, Inc. (NASDAQ: SGEN), a global biotechnology company, today announced enrollment of the first patient in a multicenter phase 1 clinical trial of SGN-CD352A for patients with relapsed or refractory multiple myeloma (MM). SGN-CD352A is an investigational CD352-targeted antibody-drug conjugate (ADC) utilizing Seattle Genetics’ proprietary ADC technology, an engineered cysteine antibody (EC-mAb) stably linked to a highly potent cytotoxic agent called a pyrrolobenzodiazepine (PBD) dimer. CD352 is broadly expressed on B-cell cancers including multiple myeloma, chronic lymphocytic leukemia and non-Hodgkin lymphoma, while exhibiting low expression on normal white blood cells. The trial is designed to assess the safety and antitumor activity of SGN-CD352A. This study represents Seattle Genetics’ first clinical-stage ADC program in development for MM, demonstrating the breadth of potential therapeutic applications for its industry-leading ADC technology platform.

“More than 124,000 people worldwide are diagnosed annually with multiple myeloma, most relapsing or becoming resistant to current therapies,” said Robert Lechleider, M.D., Senior Vice President, Clinical Development at Seattle Genetics. “SGN-CD352A is a novel targeted investigational compound for multiple myeloma, and it is our latest antibody-drug conjugate, or ADC, in an expanding and robust pipeline of clinical stage empowered antibody therapies to address blood cancers and solid tumors. As we begin clinical development of our first compound for multiple myeloma, we continue to explore the broad potential of our ADC technology platform for people with cancer.”

The phase 1, open-label multicenter clinical study is designed to evaluate the safety and preliminary antitumor activity of SGN-CD352A as a single agent in adults with relapsed or refractory MM. The trial will be conducted in two parts, with a dose escalation part to identify the maximum tolerated dose of SGN-CD352A followed by an expansion part to further define safety and antitumor activity. SGN-CD352A will be administered every four weeks, and the study will enroll approximately 75 relapsed or refractory patients at multiple centers in the United States.

Preclinical SGN-CD352A data presented at the 2016 American Association of Cancer Research (AACR) Annual Meeting demonstrated that SGN-CD352A specifically binds to target cells and induces potent antitumor activity in both MM and non-Hodgkin lymphoma disease models. In addition to being a potential new monotherapy for MM, the tolerability profile from preclinical results suggests that SGN-CD352A may be combined with current standard of care treatments for MM. ADCs are designed to selectively deliver cell-killing agents to tumor cells, and thus may reduce many of the toxic effects of traditional chemotherapy while enhancing antitumor activity. With more than 15 years of experience and innovation, Seattle Genetics is the leader in ADC development.

For more information about the trial, including enrolling centers, please visit www.clinicaltrials.gov.

About Multiple Myeloma

Multiple myeloma (MM) is a rare and aggressive cancer that forms in white blood cells called plasma cells. Cancerous plasma cells can crowd out healthy blood cells, impair bone strength and weaken the immune system. Despite recent medical advances, MM still remains an incurable disease in which patients eventually progress and die. Within one year of first-line therapy, 32 percent of transplant patients and 44 percent of non-transplant patients relapse. Remission periods are typically shorter for each subsequent line of therapy, with some patients receiving more than four lines of treatment over the course of their disease. After lymphoma and leukemia, MM is the third most common blood cancer in the US. According to the World Health Organization, in 2015 more than 124,000 new cases of MM were diagnosed worldwide and more than 87,000 people died from the disease.

About SGN-CD352A

SGN-CD352A is a novel investigational ADC targeted to CD352 utilizing Seattle Genetics’ proprietary ADC technology. CD352 is broadly expressed on B-cell cancers including multiple myeloma, chronic lymphocytic leukemia, and non-Hodgkin lymphoma, while exhibiting low expression on normal white blood cells. The CD352 engineered cysteine antibody is stably linked to a highly potent DNA binding agent called a pyrrolobenzodiazepine (PBD) dimer via site-specific conjugation technology (EC-mAb). PBD dimers are significantly more potent than systemic chemotherapeutic drugs and the EC-mAb technology allows uniform drug-loading onto an ADC. The ADC is designed to be stable in the bloodstream and to release its potent cell-killing PBD agent upon internalization into CD352-expressing cells.

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 66 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

Forward Looking Statements

Certain of the statements made in this press release are forward looking, such as those, among others, relating to the therapeutic potential of SGN-CD352A and its possible benefits and uses, and planned clinical trials including potential patient and site enrollment. 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 this recently initiated clinical trial and the risk of adverse events as SGN-CD352A advances in clinical trials and regulatory actions. 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 September 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.

Contacts

Seattle Genetics, Inc.
Investors:
Peggy Pinkston, 425-527-4160
ppinkston@seagen.com
or
Media:
Kavita V. Shah, Ph.D., 425-527-4188
kshah@seagen.com

Contacts

Seattle Genetics, Inc.
Investors:
Peggy Pinkston, 425-527-4160
ppinkston@seagen.com
or
Media:
Kavita V. Shah, Ph.D., 425-527-4188
kshah@seagen.com