FDA places clinical hold on several Phase I trials of Vadastuximab Talirine

Six patients have been identified with hepatotoxicity, including several cases of veno-occlusive disease, with four fatal events.

Overall, more than 300 patients have been treated with SGN-CD33A in clinical trials across multiple treatment settings. Seattle Genetics is working diligently with the FDA to determine whether there is any association between hepatotoxicity and treatment with SGN-CD33A, to promptly identify appropriate protocol amendments for patient safety and to enable continuation of these trials.

The Phase I/II trial of SGN-CD33A monotherapy in pre- and post-allogeneic transplant AML patients has been placed on full clinical hold. Two Phase I trials have been placed on partial clinical hold (no new enrollment, existing patients may continue treatment with re-consent). These studies are SGN-CD33A monotherapy, including a subset of older AML patients in combination with hypomethylating agents, and SGN-CD33A combination treatment with 7+3 chemotherapy in newly diagnosed younger AML patients. No new studies will be initiated until the clinical holds are lifted.

Seattle Genetics’ other ongoing trials of SGN-CD33A, including the Phase III CASCADE trial in older AML patients and Phase I/II trial in myelodysplastic syndrome, are proceeding with enrollment.