PF-06463922 for Crizotinib Pretreated ROS1 Positive Non-small-cell Lung Cancer

PF-06463922 is a novel small-molecule ROS1/ALK inhibitor that was optimized for robust brain penetration. The results showed that PF-06463922 is most potent against ROS1 and ALK, with selectivity ratios \>100-fold for ROS1 over the 204 kinases tested. A recent study has investigated the activity of PF-06463922 against the crizotinib-resistant ROS1G2032R mutation in both recombinant enzyme and cell-based assays. PF-06463922 effectively inhibited the catalytic activity of recombinant ROS1G2032R and the CD74-ROS1G2032R fusion kinase in BaF3 cells. This effect translated directly into an antiproliferative response. These results, together with its exquisite ROS1 potency and ability to suppress the resistant ROS1 mutations, supports the clinical evaluation of PF-06463922 in ROS1-positive NSCLC, including patients who have developed resistance to crizotinib because of the acquired G2032R mutation and/or brain metastases. This is a phase II study assessing response rate to PF-06463922 in patients with ROS1 translocation resistant to previous crizotinib therapy. Eligible patients will be treated with the study drug until disease progression, unacceptable toxicity or patient refusal. Disease assessment will be performed every 8 weeks according to RECIST criteria.