FDA Places Partial Clinical Hold on Xencor Clinical Trial Following Two Patient Deaths

The U.S. Food and Drug Administration (FDA) has placed a partial clinical hold on Xencor’s Phase I acute myeloid leukemia study due to the death of two patients in the trial. In an announcement this morning, Xencor said the regulatory agency has halted new enrollment of patients in the Phase I trial assessing XmAb14045, a CD123 x CD3 bispecific antibody molecule being evaluated in patients with relapsed or refractory acute myeloid leukemia and other CD123-expressing hematologic malignancies. Xencor said the FDA placed the partial clinical hold following recent safety reports submitted by the company. The company sent the report following the death of two patients, which could be related to XmAb14045, the company said. According to its announcement, one of the patients in the study experienced cytokine release syndrome after receiving the first dose of XmAb14045. Xencor said the treatment of the cytokine release syndrome was complicated due to the patient’s decision to withdraw from care. The other patient developed acute pulmonary edema following several doses of XmAb14045, Xencor said this morning.