Evandro Bezerra, MD, Mayo Clinic, Rochester, MN, discusses the results of a pre-clinical study investigating the best strategy to inhibit the GM-CSF pathway to decrease the toxicity of CD19-directed CAR-T therapy. Overall, the study found that in vitro models treated with GM-CSF receptor blockade led to impaired CAR-T proliferation whilst treatment with a monoclonal antibody against the GM-CSF cytokine did not have this effect. This was confirmed in in vivo models, where it was also shown that GM-CSF receptor blockade resulted in impaired anti-tumor immunity and decreased survival. Ongoing experiments are exploring the mechanisms leading to the differences observed with GM-CSF neutralization and receptor blockade. This interview took place at the Transplantation & Cellular Therapy (TCT) Meetings of ASTCT™ and CIBMTR® 2022 in Salt Lake City, Utah.