Millennium, Seattle Genetics' new brentuximab vedotin trial data presented at ASCO 2011

Seattle Genetics, Inc. (Nasdaq: SGEN) and Millennium: The Takeda Oncology Company, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited (TSE:4502), today reported updated data from a pivotal trial of brentuximab vedotin (ADCETRIS™) in relapsed or refractory Hodgkin lymphoma and a phase II trial in relapsed or refractory systemic anaplastic large cell lymphoma (ALCL). Brentuximab vedotin is an antibody-drug conjugate (ADC) directed to CD30, a defining marker of Hodgkin lymphoma and systemic ALCL, and a target also expressed in other malignancies. The updated data were presented today during poster presentations at the American Society of Clinical Oncology (ASCO) 2011 Annual Meeting being held in Chicago, IL.

In a pivotal trial of 102 relapsed or refractory Hodgkin lymphoma patients who had failed prior autologous stem cell transplant (ASCT), an independent review facility (IRF) evaluated the overall objective response rate and duration of responses. Per IRF, it was previously reported that 75 percent of patients achieved an objective response, including 34 percent with a complete remission (CR). The median duration of response for all responding patients was 6.7 months, and the median duration of response for patients achieving a CR had not yet been reached. In these updated data presented at ASCO based on additional patient follow-up, the median duration of response in patients with a CR was 20.5 months per IRF. At the time of last data analysis, 21 patients with a CR were alive and free of progression. The estimated 12-month overall survival for all patients was 89 percent. Patient follow-up is ongoing. (Abstract #8031)

In a phase II trial of 58 relapsed or refractory systemic ALCL patients, it was previously reported that, per IRF, 86 percent of patients achieved an objective response, including 53 percent with a CR. When previously reported, the median duration of response for all responding patients and for patients with a CR had not yet been reached. In updated data presented at ASCO based on additional patient follow-up, the rate of CRs per IRF increased to 57 percent. The median duration of overall objective response was 12.6 months and the median duration of response in patients with a CR was 13.2 months, both per IRF. Median overall survival had not been reached. Patient follow-up is ongoing. (Abstract #8032)

Across both trials, brentuximab vedotin treatment was associated with generally manageable adverse events. The most common adverse events of any Grade in the pivotal Hodgkin lymphoma trial were peripheral sensory neuropathy (47 percent), fatigue (46 percent), nausea (42 percent), upper respiratory tract infection (37 percent) and diarrhea (36 percent). The most common adverse events of any Grade in the phase II systemic ALCL trial were peripheral sensory neuropathy (41 percent), nausea (40 percent), fatigue (38 percent), fever (34 percent) and diarrhea (29 percent).

"The durability of the complete remissions among these highly treatment-refractory Hodgkin lymphoma patients is clinically meaningful, as it is uncommon for single-agent treatment to achieve complete remissions with a duration of more than 18 months," said Dr. Robert Chen, Assistant Professor, Hematology & Hematopoietic Cell Transplantation at City of Hope and the 2010-2011 recipient of the Tim Nesvig Research Fellowship in Lymphoma. "There is a substantial unmet medical need in this setting, evidenced by historical data showing that almost half of Hodgkin lymphoma patients who relapse following ASCT will survive less than two years. The activity and tolerability data with brentuximab vedotin suggest that, if approved, brentuximab vedotin could be an important option for relapsed or refractory patients."

"Systemic ALCL is an aggressive type of T-cell non-Hodgkin lymphoma for which there is a pronounced unmet need, particularly for patients with highly refractory disease such as those in this clinical trial," said Dr. Andrei Shustov, Assistant Professor of Hematology at the University of Washington School of Medicine and Attending Physician in the Hematologic Malignancies Program at the Seattle Cancer Care Alliance. "The overall response rate of 86 percent previously reported, combined with the new duration of response data presented at ASCO, continue to support the clinical development of brentuximab vedotin for relapsed or refractory systemic ALCL patients. These data also provide rationale for future clinical studies in other CD30-positive tumors."