Alectinib inhibits ALK with an IC50 value of 1.9 nmol/L and shows higher selectivity for ALK than for a number of other serine/tyrosine kinases. It also inhibits the ALK gatekeeper mutation L1196M with an IC50 of 1.56 nmol/L. Alectinib is effective with crizotinib-resistant ALK mutations L1196M, F1174L, R1275Q and C1156Y. In the KARPAS-299 (lymphoma), NB-1 (neuroblastoma) and NCI-H2228 (lung cancer) ALK-positive cell lines, alectinib inhibits cell proliferation with IC50 values of 3, 4.5 and 53 nmol/L, respectively.
In vivo
Alectinib dose-dependently inhibits EML4-ALK positive NCI-H2228 xenograft model at doses ranging from 2 to 20 mg/kg p.o., q.d. Significant efficacy is also achieved in the EML4-ALK L1196M-driven tumors. It has antitumor activity against cancers with ALK gene alterations.