Phase III Trials of Vadastuximab Talirine Discontinued Amid Safety Concerns

Seattle Genetics, Inc. announced the discontinuation of the phase III CASCADE trial of vadastuximab talirine (also known as SGN-CD33A) in older patients newly diagnosed with acute myeloid leukemia following a review of unblinded data on June 16, 2017, and consultation with the Independent Data Monitoring Committee. It is also suspending patient enrollment and treatment in all vadastuximab talirine clinical trials.

Data from the randomized, double-blind, placebo-controlled trial indicated that patients assigned to receive vadastuximab talirine in combination with hypomethylating agents (HMAs) had higher rates of death than those in the control arm (in which patients received only HMAs). These deaths were related to fatal infection, and the company noted that none appeared to be associated with hepatotoxicity.

In December 2016, the U.S. Food and Drug Administration (FDA) placed a clinical hold on several phase I trials of vadastuximab talirine after four patient deaths. In March 2017, the hold was lifted after a comprehensive re-evaluation of 300 patients to ensure patient safety.

Calling the results “disappointing and unexpected,” the manufacturer stated that it plans to consult with the FDA to determine future plans for the vadastuximab talirine development program.

Source: Seattle Genetics press release, June 19, 2017.