TY - JOUR
T1 - Selective Btk inhibition by PRN1008/PRN473 blocks human CLEC-2, and PRN473 reduces venous thrombosis formation in mice
AU - Smith, Christopher W
AU - Campos, Joana
AU - Brown, Helena C
AU - Jooss, Natalie J
AU - Ivanova, Vanesa-Sindi
AU - Harbi, Maan
AU - Garcia-Quintanilla, Lourdes
AU - Jossi, Sian
AU - Perez-Toledo, Marisol
AU - Rookes, Kieran
AU - Brill, Alexander
AU - Theodore, Lindsay N
AU - Owens, Tim
AU - LaStant, Jacob
AU - Foulke, Matthew C
AU - Mukai, Shin
AU - Francesco, Michelle
AU - Storek, Michael
AU - Hicks, Alexandra
AU - Langrish, Claire
AU - Nunn, Philip A
AU - Cunningham, Adam F
AU - Chauhan, Abhi
AU - Thomas, Mark R
AU - Watson, Steve P
AU - Nicolson, Phillip L R
PY - 2024/11/12
Y1 - 2024/11/12
N2 - Platelet C-type lectin-like receptor 2 (CLEC-2) is a hem-immunoreceptor tyrosine-based activation motif-containing receptor that has a critical role in venous thrombosis but minimal involvement in hemostasis. CLEC-2 can be blocked by Btk inhibitors. Treatment with ibrutinib is associated with increased bleeding due to off-target inhibition of Src family kinases (SFKs). Patients with X-linked agammaglobulinemia (XLA) who lack Btk, however, do not bleed, suggesting selective Btk inhibition as a viable antithrombotic strategy. We assessed the effects of selective Btk inhibitors PRN1008 (rilzabrutinib) and PRN473 on platelet signaling and function mediated by CLEC-2 and glycoprotein-VI. We used healthy donors and XLA platelets to determine off-target inhibitor effects. Inferior vena cava (IVC) stenosis and Salmonella infection mouse models were used to assess antithrombotic effects of PRN473 in vivo. PRN1008 and PRN473 potently inhibited CLEC-2-mediated platelet activation to rhodocytin. No off-target inhibition of SFKs was seen. PRN1008 treatment of Btk-deficient platelets resulted in minor additional inhibition of aggregation and tyrosine phosphorylation, likely reflecting inhibition of Tec. No effect on G protein-coupled receptor-mediated platelet function was observed. PRN473 significantly reduced the number of thrombi in podoplanin-positive vessels after Salmonella infection and the presence of IVC thrombosis after vein stenosis. The potent inhibition of human platelet CLEC-2 and reduced thrombosis in in vivo models, together with the lack of off-target SFK inhibition and absence of bleeding reported in rilzabrutinib-treated patients with immune thrombocytopenia, suggest Btk inhibition as a promising antithrombotic strategy.
AB - Platelet C-type lectin-like receptor 2 (CLEC-2) is a hem-immunoreceptor tyrosine-based activation motif-containing receptor that has a critical role in venous thrombosis but minimal involvement in hemostasis. CLEC-2 can be blocked by Btk inhibitors. Treatment with ibrutinib is associated with increased bleeding due to off-target inhibition of Src family kinases (SFKs). Patients with X-linked agammaglobulinemia (XLA) who lack Btk, however, do not bleed, suggesting selective Btk inhibition as a viable antithrombotic strategy. We assessed the effects of selective Btk inhibitors PRN1008 (rilzabrutinib) and PRN473 on platelet signaling and function mediated by CLEC-2 and glycoprotein-VI. We used healthy donors and XLA platelets to determine off-target inhibitor effects. Inferior vena cava (IVC) stenosis and Salmonella infection mouse models were used to assess antithrombotic effects of PRN473 in vivo. PRN1008 and PRN473 potently inhibited CLEC-2-mediated platelet activation to rhodocytin. No off-target inhibition of SFKs was seen. PRN1008 treatment of Btk-deficient platelets resulted in minor additional inhibition of aggregation and tyrosine phosphorylation, likely reflecting inhibition of Tec. No effect on G protein-coupled receptor-mediated platelet function was observed. PRN473 significantly reduced the number of thrombi in podoplanin-positive vessels after Salmonella infection and the presence of IVC thrombosis after vein stenosis. The potent inhibition of human platelet CLEC-2 and reduced thrombosis in in vivo models, together with the lack of off-target SFK inhibition and absence of bleeding reported in rilzabrutinib-treated patients with immune thrombocytopenia, suggest Btk inhibition as a promising antithrombotic strategy.
KW - Lectins, C-Type/metabolism
KW - Animals
KW - Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors metabolism
KW - Humans
KW - Mice
KW - Venous Thrombosis/etiology drug therapy metabolism
KW - Blood Platelets/metabolism drug effects
KW - Agammaglobulinemia/drug therapy
KW - Disease Models, Animal
KW - Protein Kinase Inhibitors/pharmacology therapeutic use
KW - Genetic Diseases, X-Linked/drug therapy
KW - Platelet Membrane Glycoproteins/metabolism antagonists & inhibitors
KW - Pyrimidines/pharmacology therapeutic use
KW - Membrane Glycoproteins
U2 - 10.1182/bloodadvances.2024012713
DO - 10.1182/bloodadvances.2024012713
M3 - Article
SN - 2473-9529
VL - 8
SP - 5557
EP - 5570
JO - Blood advances
JF - Blood advances
IS - 21
ER -