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.

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.

Inclusion Criteria:

1. Written informed consent;
2. Male or female patient ages ≥ 18 years;
3. Histologically/cytologically confirmed diagnosis of NSCLC with evidence of ROS1 rearrangement;
4. Possibility to perform a new tumor biopsy or tumor tissue collected at the time or after crizotinib failure;
5. Patient pretreated with crizotinib with evidence of disease progression during crizotinib therapy;
6. At least one radiological measurable disease according to RECIST criteria;
7. At least 1 previous standard chemotherapy regimen;
8. Performance status 0-2 (ECOG);
9. Patient compliance to trial procedures
10. Adequate bone marrow function (ANC ≥ 1.5x109/L, platelets ≥ 100x109/L, haemoglobin > 9 g/dl);
11. Adequate liver function (bilirubin < grade 2, transaminases no more than 3xULN/<5xULN in present of liver metastases);
12. Normal level of alkaline phosphatase and creatinine;
13. If female: childbearing potential either terminated by surgery, radiation, or menopause, or attenuated by use of approved contraceptive method [intrauterine contraceptive device (IUD), birth control pills, or barrier device] during and for ninety (90) days after end of treatment.

Exclusion Criteria:

1. No ROS1 rearrangement 2. No previous therapy with crizotinib; 3. No evidence of crizotinib failure; 4. No post-crizotinib tumor tissue available; 5. Absence of any measurable lesions; 6. No previous chemotherapy; 7. Concomitant radiotherapy or chemotherapy; 8. Symptomatic brain metastases; 9. Diagnosis of any other malignancy during the last 5 years, except for in situ carcinoma of cervix uteri and squamous cell carcinoma of the skin; 10. Predisposing factors for acute pancreatitis (e.g., uncontrolled hyperglycaemia, current gallstone disease, alcoholism); 11. History of extensive disseminated/bilateral or known presence of Grade 3 or 4 interstitial fibrosis or interstitial lung disease including a history of pneumonitis, hypersensitivity pneumonitis, interstitial pneumonia, interstitial lung disease, obliterative bronchiolitis and pulmonary fibrosis (but not history of prior radiation pneumonitis); 12. Pregnancy or lactating female; 13. Other serious illness or medical condition potentially interfering with the study.

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