Towards Identifying Which CLL Patients with Richter Transformation Respond to Immune Checkpoint Inhibitor Therapy

Pre-existing cytotoxic activity in CD8⁺ and CD4⁺ T cells is a key characteristic of Richter transformation in patients with CLL and increases the likelihood of response to anti–PD-1 therapy. Although immune checkpoint inhibitors have shown promising results in Richter transformation, the factors within the tumor microenvironment that determine response or resistance are not yet fully understood.

At ASH 2025, Johan Gustafsson presented data from a study aimed at addressing this knowledge gap. In this MEDtalk, he presents results suggesting that preserved splenic tissue architecture, the presence of immune cell aggregates, and more functional cytotoxic T cells are critical for the effectiveness of immune checkpoint blockade in Richter transformation.