The company is now waiting for the FDA to determine a path forward in resuming clinical studies.
Shares of Houston-based Bellicum Pharmaceuticals plunged more than 48 percent in aftermarket trading after the company announced the U.S. Food and Drug Administration slapped a clinical hold on its lead cell therapy product after three cases of encephalopathy were reported.
The company said the encephalopathy, a fairly broad term for brain damage, could have been related to its experimental therapy candidate BPX-501. BPX-501 is an adjunct T cell therapy administered to patients after allogeneic hematopoietic stem cell transplant (HSCT). Bellicum has been focused on three primary goals with BPX-501 – fighting infection, aid engraftment and stop disease relapse.
Bellicum said it was waiting for the FDA to determine a path forward in resuming clinical studies. The company said it is working closely with the FDA during this time. Bellicum was sure to point out that the clinical hold does not affect the ongoing BP-004 registration trial in Europe, which is a renamed version of BPX-501.
The company had been billing BPX-501 as a safer option for stem cell transplants. The company said administering BPX-501 engineered T cells to speed immune reconstitution “provide control over viral infections and enhance Graft-versus-leukemic effect without unacceptable GvHD risk.”
Still, Bellicum said encephalopathy has been reported in the allogeneic stem cell transplant literature. The company added that risk factors for encephalitis/encephalopathy after allogeneic stem cell transplants include prolonged immunodeficiency, selected medications, infections, and inflammatory processes such as graft versus host disease.
In its announcement, Bellicum provided few details about the three cases of brain damage. The company did note that the three patients who developed encephalopathy are complex and have a “number of potential confounding factors.” Those factors include prior failed transplants, prior history of immunodeficiency, concurrent infection, and administration of rimiducid in combination with other medications, the company said. Bellicum added that it has treated more than 240 patients with BPX-501 cells on three allogeneic haploidentical stem cell transplantation protocols.
In December, Bellicum presented data from its BP-004 trial in Europe for children with blood cancers and nonmalignant disorders. Patients were treated with BPX-501 following an alpha/beta T cell and CD19+ B cell depleted haploidentical hematopoietic stem cell transplant (haplo-HSCT). Results demonstrated that donor BPX-501 cells infused after transplant expanded in vivo and persisted over time, contributing to improved immune recovery for patients in the study as compared to historical controls from the same transplant center, the company said. The company’s lead researcher Pietro Merli said the data said administering BPX-501 cells following a haplo-HSCT may result in improved immune recovery and infection control. The company has been hoping to seek approval for BP-004 in 2019, but that could be delayed if the European Medicines Agency also opts to place a hold on the trial.
In November, Bellicum said it anticipated ending 2017 with approximately $90 to $95 million in cash, cash equivalents and investments. The company said it anticipated those funds would be sufficient to carry it through 2018, but the clinical hold may negatively impact that outlook.
