The action was taken by the biotechnology company after consultation with the Independent Data Monitoring Committee (IDMC) and a review of the unblinded data of the trial dubbed CASCADE.
Data recorded from the trial in frontline older AML patients also disclosed fatal infections along with high incidents of deaths in the vadastuximab talirine-containing arm compared to the control arm of the phase 3 trial.
The trial studied the combination of vadastuximab talirine and hypomethylating agents (HMAs) azacitidine or decitabine in comparison to HMA only treatment in older patients who have been newly diagnosed with AML.
Seattle Genetics stated that on the basis of the available data, the safety issues in the trial do not seem to be associated with hepatotoxicity.
The company said that it has stopped enrolling patients and treatment in all its clinical trials that are evaluating vadastuximab talirine. Included in the suspended trials is the current phase 1/2 trial in frontline high risk myelodysplastic syndrome (MDS) patients.
Seattle Genetics president and CEO Clay Siegall said: “This is a disappointing and unexpected result for the CASCADE trial. Patient safety is our highest priority, and we will closely review the data and evaluate next steps.
“AML is a devastating disease with a poor prognosis in most patients, and there is a great need for therapeutics against this disease.”
Vadastuximab talirine is an antibody-drug conjugate (ADC) that uses Seattle Genetics’ proprietary ADC technology to target CD33, a transmembrane receptor that is expressed on most AML and MDS blast cells.