Effect of second-generation BTK inhibitors on the functionality of macrophages and neutrophils from CLL patients.

ANA COLADO; MARICEF VERGARA RUBIO; FERNÁNDEZ GRECCO HORACIO; FLORENCIA AIZPURUA; PABLO MORANDE; GAMBERALE ROMINA; JOSÉ LUIS MARÍN FRANCO; CORDINI, GREGORIO; SANTIAGO CRANCO; MARTA ZERGA; FERNANDO BEZARES; BORGE MERCEDES; ESTEBAN ELÍAS; ALEXIA VEREERTBRUGGHEN; CAROLINA MAHUAD; LUCIANA BALBOA; GIORDANO MIRTA

Edimburgo

Workshop; XVIII International Workshop on Chronic Lymphocytic Leukaemia; 2019

iwCLL Consortium

The development of BTK inhibitors (BTKi) has changed the treatment landscape in CLL.To date, ibrutinib is the only BTKi approved for CLL treatment, while second generationBTKi with greater selectivity for BKT, such as acalabrutinib, approved for MCL, andspebrutinib, are being evaluated in clinical trials. Besides its effects on leukemic B-cells,ibrutinib also affects key innate immune cells such as macrophages and neutrophils. Inthis regard we and others have reported that ibrutinib impairs macrophage-M1 polarizationand macrophage response to TLR`s ligands, Mycobacterium tuberculosis (Mtb) andAspergillus fumigatus (Colado A, et al. Blood Cancer Journal. 2018, Fiorcari, S et al.Oncotarget. 2016, Bercusson A, et al. Blood, 2018), while others have reported thatibrutinib affects neutrophil functionality (Stadler, N. et al. Haematologica. 2017).Infections are a main cause of morbidity and mortality in CLL, and while rates of infectionsduring ibrutinib treatment are similar or lower compared to other treatments (Ball S, et al.European journal of haematology. 2018 and O´Brien S, Clinical Lymphoma, Myeloma &Leukemia. 2018), they are still one of the most frequent adverse events (O´Brien S, et al.Blood. 2018), and they are among the most common toxicities leading to drugdiscontinuationin relapsed/refractory patients (Mato A, et al. Haematologica. 2018).Therefore, to better understand the impact of new agents on immune cells may help toimprove CLL patients´ care. Our aim was to investigate how second generation BTKi affectmacrophage and neutrophil functions.First we evaluated the effect of acalabrutinib and spebrutinib on macrophage polarizationtowards the IFN-γ-induced M1 profile, which is associated with an effective anti-microbialimmune response. To this aim, human monocytes were cultured with GM-CSF and IFN-γwith or without BTKi at clinically relevant doses. We found that, similar to ibrutinib,acalabrutinib impaired M1 polarization as shown by the down-regulation in the expressionof the M1-associated marker CD86, the decrease in TNF-α secretion, the up-regulation ofthe M2-associated markers CD16, CD14, CD163, CD206 and the increase in IL-10secretion. In contrast, we found that spebrutinib did not modify M1/M2 markers or cytokinesecretion (Figure 1A-G).When we analyzed the effect of the BTKi on macrophage response towards microbialstimulation we found that acalabrutinib, as reported for ibrutinib, significantly decreasedTNF-α secretion by macrophages stimulated with irradiated-Mtb, heat inactivatedAspergillus fumigatus conidia or heat-inactivated Candida albicans yeast (Figure 1H-J). Inline with this, we found that ibrutinib and acalabrutinib impaired TNF-α secretion whenmacrophages were stimulated with Pam3CSK4, a TLR2 ligand, or zymosan a TLR2 andDectin-1 ligand, which are receptors involved in macrophage-recognition of Mtb and fungi(n=8, p