Understanding clinical development of chimeric antigen receptor T cell therapies

Background aims: In the past decade, many clinical trials with gene- and cell-based therapies (GCTs) have been performed. Increased interest in the development of these drug products by various stakeholders has become apparent. Despite this growth in clinical studies, the number of therapies receiving marketing authorization approval (MAA) is lagging behind. To enhance the success rate of GCT development, it is essential to better understand the clinical development of these products. Chimeric antigen receptor (CAR) T cells are a GCT product subtype with promising efficacy in cancer treatment which are tested in many clinical trials, but have not yet received MAA.

Methods: We generated an overview of the characteristics of CAR T-cell clinical development in the United States, Canada and Europe. Subsequently, the characteristics of clinical trials with CAR T-cell products that proceeded to a subsequent clinical trial, used as a proxy for success, were compared with those that did not proceed.

Result: From the U.S. and European Union clinical trial databases, 106 CAR T-cell trials were selected, from which 49 were linked to a subsequent trial and 57 were not. The majority of the trials had an academic sponsor from which most did not proceed, whereas most commercially sponsored trials were followed by another clinical trial. Furthermore, trials with a subsequent trial more frequently recruited large patient cohorts and were more often multicenter compared with trials that were not followed up.

Discussion: These characteristics can be used by investigators to better design clinical trials with CAR T cells. We encourage sponsors to plan clinical development ahead for a higher efficiency of product development and thereby achieving a higher success rate of development towards MAA.