Mechanism of Action

BTK inhibition blocks B cell signaling and proliferation1

Kinase Selectivity

Acalabrutinib: a next-generation BTK inhibitor that delivers focused kinase inhibition and limited off-target activity2,3

Visualization of Kinase Selectivity2,3

Kinase Selectivity2,3
 Number of Kinases Bound
Compounda >65% Bound>90% Bound>99% Bound
Acalabrutinib741b
Ibrutinib372513
Zanubrutinib19134
aA total of 395 non-mutant kinases were screened in the testing of acalabrutinib and ibrutinib (conducted in 2014) and testing of zanubrutinib (conducted in 2017) included 8 additional kinases (total of 403 screened). The additional 8 kinases were not inhibited by >65% by zanubrutinib; bThe only kinase with >99% bound at 1 μM was BTK.

Abbreviations

AGC = protein kinase A, G, and C families

;

AKT = protein kinase B

;

BCL-10 = B-cell lymphoma/leukemia 10

;

BCR = B-cell receptor 

;

BLNK = B-cell linker protein

;

BTK = Bruton tyrosine kinase

;

CAMK = calmodulin/calcium-regulated kinases

;

CARD11 = caspase recruitment domain-containing protein 11

;

CBM = CARD11–BCL‑10–MALT1

;

CD = cluster of differentiation

;

CK1 = casein kinase 1

;

CIN85 = Cbl-interacting protein of 85 kDa

;

CMGC = CDK, MAPK, GSK3, and CLK

;

DAG = diacylglycerol

;

IgH = immunoglobulin heavy chain

;

IgL = immunoglobulin light chain

;

IKK = inhibitor of NF-κB kinase

;

MALT1 = mucosa-associated lymphoid tissue lymphoma translocation protein 1

;

MAPK = mitogen-activated protein kinase

;

mTOR = mammalian target of rapamycin

;

NF-kB = nuclear factor kappa-light chain enhancer of activated B cells

;

NFAT = nuclear factor of activated T cells

;

PI3K = Phosphatidylinositol 3-kinase

;

PIP = phosphatidylinositol

;

PKC = protein kinase C

;

PLC = phospholipase C

;

SFK = SRC-family kinase

;

SYK = spleen tyrosine kinase

;

STE = homologs of the yeast STE7, STE11, and STE20 genes

;

TK = tyrosine kinases

;

TKL = tyrosine kinase-like

References

1. Young RM, Staudt LM, et al. Targeting pathological B cell receptor signalling in lymphoid malignancies. Nat Rev Drug Discov. 2013;12(3)229-43. DOI:10.1038/nrd3937. 
2. Barf T, Covey T, Izumi R, et al. Acalabrutinib (ACP-196): A Covalent Bruton Tyrosine Kinase Inhibitor with a Differentiated Selectivity and In Vivo Potency Profile. J Pharmacol Exp Ther. 2017;363(2):240-252. doi:10.1124/jpet.117.242909
3. Kaptein A, de Bruin G, Emmelot-van Hoek M, et al. Potency and selectivity of BTK inhibitors in clinical development for B cell malignancies. Presented at: American Society of Hematology (ASH); December 1-4, 2018; San Diego, CA. Abstract #1871.

Document ID: 03435135-2ea5-4261-b52b-476f8c4a6afb
Last updated: 17-April-2023