Bellicum Pharmaceuticals announced interim phase 2 data of its T cell therapy in children with acute myeloid leukemia (AML) and primary immunodeficiencies. The data show that the treatment, BPX-501, “may contribute” to a long-lasting anticancer effect in AML, the company said.
BPX-501 is an adjunct T cell therapy given to patients after they receive a transplant of haploidentical hematopoietic stem cells, or stem cells that match the patients’ tissue type and can develop into any type of blood cell. The treatment has a built-in “safety switch” called CaspaCIDe, which can be triggered to kill the engineered T cells if they cause side effects, like Graft-versus-host disease.
At the one-year mark, the study posted high rates of relapse-free survival and overall survival in 38 AML patients: 91.5% and 97.3% respectively.
“The recurrence of cancer is one of the most serious risks to AML patients receiving a stem cell transplant. These impressive results in children with AML suggest that BPX-501 may be effectively reducing or eradicating residual cancer cells following a haplo-transplant procedure,” said Neena Kapoor, M.D., director of the Blood and Marrow Transplantation Program at Children’s Hospital of Los Angeles and an investigator in the trial.
The data for 59 patients with primary immunodeficiencies (PIDs) were also encouraging—for patients with Severe Combined Immunodeficiency, Wiskott-Aldrich syndrome, Chronic Granulomatous Disease and other rare immune deficiencies, the disease-free survival rate was 88.1% and overall survival was 88.6% after one year.
“Delayed immune reconstitution can lead to severe infectious complications, a major cause of morbidity and mortality in PID patients who undergo a T-depleted [haploidentical hematopoietic stem cell transplant]. BPX-501 donor T cells administered after a transplant support immune recovery in these patients, and the CaspaCIDe safety switch engineered into BPX-501 may provide a critical safety net to address the risk of uncontrolled [Graft-versus-host disease] from donor T cells,” Kapoor said.
Bellicum is working with the FDA on a potential registration study for pediatric patients in the U.S. and hopes to start it by the end of the year. But that depends on the agency lifting a clinical hold it placed on all U.S. trials of BPX-501 in January, after learning of three cases of brain damage that were possibly related to the treatment. Barely a week after the FDA set the hold, Bellicum reinforced its leadership, adding Genentech alum William Grossman as chief medical officer.