Seattle Genetics starts phase 3 trial of vadastuximab talirine for newly diagnosed AML patients

About 500 patients will be enrolled in the randomized, double-blind, placebo-controlled phase 3 study, dubbed Cascade, which will assess 33A in combination with azacitidine (Vidaza) or decitabine (Dacogen) in older AML patients.

It will evaluate if 33A in combination with azacitidine or decitabine can extend overall survival compared to azacitidine or decitabine alone in older patients with newly diagnosed AML.

Patients will be randomized on a 1:1 ratio to be treated with an HMA and 33A or an HMA plus placebo.

Secondary endpoints of the trial include the comparison of composite complete remission rate, event-free and leukemia-free survival, duration of response, safety, and 30- and 60-day mortality rates.

Seattle Genetics president and CEO Clay Siegall said: "We have a robust development strategy, with several ongoing clinical trials across multiple lines of therapy in myeloid malignancies to explore 33A as a treatment option broadly in AML.

"This pivotal phase 3 CASCADE trial is a significant corporate milestone and an important step in our goal to improve outcomes for AML patients."

AML affects about 20,000 people in the US per year, with few effective treatment options.

Data from the phase 1 33A combination trial showed that 15 of 23 evaluable patients achieved CR/CRi.

Seattle Genetics said median survival had not yet been reached at a median follow-up of 7.7 months, and 72% of patients remained alive and on study.