The Food and Drug Administration (FDA) informs Bellicum Pharmaceuticals that studies of BPX-501 have been placed on a clinical hold following 3 cases of encephalopathy deemed as possibly related to BPX-501. The FDA clinical hold does not affect the ongoing BP-004 registration trial in Europe. Bellicum has treated more than 240 patients with BPX-501 cells on 3 allogeneic haploidentical stem cell transplantation protocols. These 3 cases are complex, with a number of potential confounding factors, including prior failed transplants, prior history of immunodeficiency, concurrent infection, and administration of rimiducid in combination with other medications. Bellicum is working with the FDA to evaluate the risk of encephalopathy in patients receiving BPX-501.