Acalabrutinib

Biological Activity

In vitro: In the in vitro signaling assay on primary human CLL cells, acalabrutinib inhibits tyrosine phosphorylation of downstream targets of ERK, IKB, and AKT. Acalabrutinib demonstrates higher selectivity for BTK with IC50 determinations on nine kinases with a cysteine residue in the same position as BTK. Importantly, unlike ibrutinib, acalabrutinib does not inhibit EGFR, ITK, or TEC. acalabrutinib has no effect on EGFR phosphorylation on tyrosine residues Y1068 and Y1173. Compared with ibrutinib, acalabrutinib has much higher IC50(>1000 nM) or virtually no inhibition on kinase activities of ITK, EGFR, ERBB2, ERBB4, JAK3, BLK, FGR, FYN, HCK, LCK, LYN, SRC, and YES1.

In vivo: oral administration of ACP-196 in mice results in dose-dependent inhibition of anti-IgM-induced CD86 expression in CD19+ splenocytes with an ED50 of 0.34 mg/kg compared to 0.91 mg/kg for ibrutinib. A similar model is used to compare the duration of Btk inhibition after a single oral dose of 25 mg/kg. ACP-196 inhibits CD86 expression >90% at 3h postdose.

Chemical Information

Molecular Weight	465.51
Formula	C26H23N7O2
CAS Number	1420477-60-6
Solubility (25°C)	80 mg/mL in DMSO
Storage	Powder          -20°C   3 years ;  4°C   2 years In solvent       -80°C   6 months ;  -20°C   1 month

Conversion of different model animals based on BSA (PMID: 27057123)

Species	Mouse	Rat	Rabbit	Guinea pig	Hamster	Dog
Weight (kg)	0.02	0.15	1.8	0.4	0.08	10
Body Surface Area (m2)	0.007	0.025	0.15	0.05	0.02	0.5
Km factor	3	6	12	8	5	20

Animal A (mg/kg) = Animal B (mg/kg) multiplied by	Animal B Km
	Animal A Km

For example, to modify the dose of Compound A used for a mouse (20 mg/kg) to a dose based on the BSA for a rat, multiply 20 mg/kg by the K_m factor for a mouse and then divide by the K_m factor for a rat. This calculation results in a rat equivalent dose for Compound A of 10 mg/kg.

References

[1] Wu J, et al. J Hematol Oncol. Acalabrutinib (ACP-196): a selective second-generation BTK inhibitor.

[2] Byrd JC, et al. N Engl J Med. Acalabrutinib (ACP-196) in Relapsed Chronic Lymphocytic Leukemia.