Dr. Shah on Challenges of CAR T-Cell Clinical Trials in MCL

Bijal D. Shah, MD, medical oncologist, Moffitt Cancer Center, assistant professor of oncology, University of South Florida, discusses the challenges of developing clinical trials for CAR T cells in mantle cell lymphoma (MCL).

To be eligible to enroll in the clinical trial for axicabtagene ciloleucel (axi-cel; Yescarta) , a patient with MCL must have failed on therapy with a BTK inhibitor, Shah says. Most of these patients have severe bone marrow burden and cytopenia. When the patient enrolls, there is a manufacturing period of 2 weeks that requires stoppage of treatment with ibrutinib (Imbruvica). These are patients who progress rapidly and have proliferative disease; taking them off treatment will only make this worse, Shah says.

There are future CAR T-cell therapy trials that may allow for a shorter duration off BTK inhibition, which would be beneficial. Once patients progress, their median overall survival is approximately 2 months. As a result, there really isn’t much liberty for researchers to take patients off treatment. If they have to wait 2 weeks or longer, their disease will likely look much worse at the time of the introduction of CAR T cells. Shah concludes that it is very hard to accrue patients to these trials.