Edmund K. Waller, MD, PhD, Professor, Departments of Medicine, Pathology, and Hematology and Medical Oncology at Emory University School of Medicine and Medical Director, Center for Stem Cell Processing and Apheresis at Emory, said he was not surprised to learn that bridging therapy was associated with worse survival in the U.S. Lymphoma CAR T Consortium, primarily because most of those patients had worse disease. “The biggest covariate associated with durability of response to chimeric antigen receptor (CAR) T-cell therapy is tumor burden,” he pointed out, citing observations made in the pivotal trials that patients with highly aggressive or refractory disease often did not “make it” to CAR T-cell infusion.

However, there may be other less obvious reasons. In the current study, Dr. Waller said, “the investigators matched for things that could be matched but did not match for things that were in the doctors’ heads that led them to give bridging therapy…. It was the physician’s choice to give or not give bridging therapy, and while they tried to control for many things, they couldn’t identify why physicians chose bridging therapy.”

Dr. Waller agreed with Dr. Jain that the choice to give bridging therapy should be highly individualized. “The patient with more indolent disease will always do better [with bridging therapy], and those with lower-bulk disease will do better,” he said. “If the patient has aggressive disease, and you need to control it with bridging therapy, then that’s what you have to do.”

DISCLOSURE: Dr. Waller has served as a consultant and clinical investigator for Novartis, Pharmacyclics, and Verastem and is a founder of Cambium Oncology, an oncology products company, and Cambium Medical Technologies, a regenerative medicine company.