Evaluation of the novel therapeutic anti-CCR7 antibody CAP-100 as an add-on therapy in chronic lymphocytic leukemia patients receiving venetoclax.

The Bruton's tyrosine kinase inhibitor ibrutinib and the B-cell lymphoma 2 anti-apoptotic protein inhibitor venetoclax provide high response rates in chronic lymphocytic leukemia (CLL). However, there is a growing number of patients that relapse after treatment or show refractory disease, thus new targets and agents are still needed. We have previously reported the chemokine receptor CCR7 as a relevant deregulated target in CLL and have developed CAP-100, a novel therapeutic anti-CCR7 antibody that is under evaluation for relapse/refractory CLL (NCT04704323). While CCR7 expression has been shown to be down-modulated in CLL patients treated with ibrutinib, whether venetoclax acts in a similar manner remains unaddressed. Here, we aimed to document the impact of venetoclax on CCR7 expression in CLL cells, as well as on the pre-clinical activity of CAP-100. To this end, we addressed CCR7 expression by flow cytometry and the antibody efficacy by means of in vitro chemotactic and antibody-dependent cell-mediated cytotoxicity (ADCC) assays. Our data indicate that venetoclax treatment did not significantly modify CCR7 expression pattern nor CAP-100 mechanisms of action. Together, these findings support CAP-100 as an adjuvant therapy to venetoclax that may introduce additional modes of action in CLL therapy.