Bellicum Pharmaceuticals Faces Clinical Hold After Three Patients Suffer Brain Damage

The FDA has placed Bellicum Pharmaceuticals’ ongoing studies of it’s T-cell therapy on a clinical hold after three patients in the clinical trial developed brain damage. According to the Houston, Texas-based biopharmaceutical company, they have yet to get word from the regulator about what changes will need to be made in order to resume the study.

BPX-501 is a T-cell therapy in development to improve the likelihood of success after a patient with hematological cancer or other blood disorder receives a partial-match hematopoietic stem cell transplant. The therapy is designed to serve multiple functions, including fighting infection and preventing the onset of graft versus host disease.

“One patient had a complex history with a prior history of primary immunodeficiency and had two concurrent viral infections,” said Jefferies analysts in an investor note about the clinical hold. “This patient ultimately died from encephalopathy which was confirmed through a brain biopsy. Two of the three patients had prior transplants. Also, two patients’ symptoms resolved. The cases initially were not characterized as treatment-related adverse events but after the one fatality both cases were reviewed and reclassified as treatment related.”

Three patients showed signs of encephalopathy in the trial of BPX-501, however Bellicum has yet to determine the cause of the adverse events. The company explains that certain medications, prolonged immunodeficiency and infections can all contribute to a patient’s risk of encephalopathy after receiving an allogenic stem cell transplant.

“Bellicum has treated more than 240 patients with BPX-501 cells on three allogeneic haploidentical stem cell transplantation protocols,” said a press release issued by Bellicum. “These three cases are complex, with a number of potential confounding factors—including, in certain of the cases, prior failed transplants, prior history of immunodeficiency, concurrent infection, and administration of rimiducid in combination with other medications.”

Bellicum said they are working with the FDA to determine the risk of brain damage in patients being treated with BPX-501. They also emphasise that a registration trial of the therapy currently being conducted in Europe will not be affected by the clinical hold.