In vitro activity: PF-06463922 demonstrates significant cell activity against ALK and a large set of ALK clinical mutations with IC50 ranging from 0.2 nM-77 nM. PF-06463922 significantly inhibits cell proliferation and induces cell apoptosis in the HCC78 human NSCLC cells harboring SLC34A2-ROS1 fusions and the BaF3-CD74-ROS1 cells expressing human CD74-ROS1. PF-06463922 also shows potent growth inhibitory activity and induces apoptosis in the NSCLC cells harboring either non-mutant ALK or mutant ALK fusions

Kinase Assay: Recombinant human wild-type and mutant ALK kinase domain proteins (amino acids 1093–1411) are produced in-house using baculoviral expression, preactivated via autophosphorylation with MgATP, and assayed for kinase activity using a microfluidic mobility shift assay. The reactions contained 1.3 nM wild-type ALK or 0.5 nM mutant ALK (appropriate to produce 15-20% phosphorylation of peptide substrate after 1 h of reaction), 3 μM 5-FAM-KKSRGDYMTMQIG-CONH2), 5 mM MgCl2, and the Km level of ATP in 25 mM Hepes, pH 7.1. The inhibitors are shown to be ATP-competitive from kinetic and crystallographic studies. The Ki values are calculated by fitting the conversion (%) to a competitive inhibition equation. ROS1 enzyme is assayed as described above for ALK, except using 0.25 nM recombinant human ROS1 catalytic domain (amino acids 1883-2347). Kinase inhibitor selectivity is evaluated using a 206-kinase panel.

Cell Assay: Cells are seeded in 96-well plates in growth medium containing 10% FBS and are cultured overnight at 37°C. The following day, serial dilutions of Lorlatinib or appropriate controls are added to the designated wells, and cells are incubated at 37°C for 72 h. A CellTiter-Glo assay is performed to determine the relative cell numbers. IC50 values are calculated by concentration-response curve fitting using a four-parameter analytical method.

In rats, PF-06463922 displays low plasma clearance, a moderate volume of distribution, a reasonable half-life, low propensity for p-glycoprotein 1-mediated efflux and a bioavailability of 100%. In vivo, PF-06463922 shows cytoreductive antitumor efficacy in the NIH3T3 xenograft models expressing human CD74-ROS1 and Fig-ROS1 via inhibition in ROS1 phosphorylation and the downstream signaling molecules, as well as inhibition of the cell cycle protein Cyclin D1 in tumors. In vivo, PF-06463922 also demonstrates marked antitumor activity in mice bearing tumor xenografts expressing EML4-ALK, EML4-ALK-L1196M, EML4-ALK-G1269A, EML4-ALK-G1202R or NPM-ALK.