Pemetrexed vs Pemetrexed Plus Cisplatin in EGFR-mutant NSCLC Patients After First Line EGFR-TKIs Failure

The study is a prospective, multi-center, open-label, randomized, and controlled phase II clinical trial. The trial will include stage IIIB/IV EGFR activating mutation positive NSCLC patients who got disease progression after frontline EGFR-TKI treatment. Clinical staging is determined according to the routine protocol, which includes enhanced chest CT scans, abdominal ultrasonography or CT scans, brain MRI or CT, and bone scintigraphy. Positron emission tomography (PET)/CT scan is optional. Measurement of acquired resistance to EGFR-TKIs is based on Jackman criteria. Eligible patients will be randomized to 2 arms. Patients in arm A will receive 4 cycles of cisplatin (75 mg/m2, d1) and pemetrexed (500 mg/m2, d1) every 3 weeks, those without disease progression (PD) and being tolerable judged by investigator will continue single-agent pemetrexed (500 mg/m2, d1) every 3 weeks as maintenance until progression or intolerable toxicities. Patients in arm B will receive pemetrexed (500 mg/m2, d1) every 3 weeks until PD or intolerable toxicities. All patients will be administrated with vitamin B12 and folic acid supplement (vitamin B12 1mg intramuscular injection at least 7 days prior to the first dose of pemetrexed and repeated approximately every 9 weeks during pemetrexed treatment till 22 days after the last dose of pemetrexed; folic acid 0.5 mg orally administered once daily from at least 7 days prior to the first dose of pemetrexed till 22 days after the last dose of pemetrexed). Efficacy data will be analyzed by intention-to-treat (ITT) population using all randomized patients, and safety data will be evaluated using CTCAE v4.0 criteria for patients who received ≥ 1 dose of study treatment. If the criteria for drug administration (absolute neutrophil count ≥1500/μl, platelets ≥100 000/μl, creatinine clearance ≥45 ml/min, no grade ≥3 nonhematologic toxicity \[except for alopecia\]) were not met, drug administration have to be delayed to allow sufficient time for recovery. If a delay of more than 42 days due to toxicity was necessary, the patient will be discontinued from the study. Dose adjustments according to hematologic toxicity at the start of a subsequent cycle of the therapy will be based on platelet and neutrophil nadir counts from the preceding cycle. Granulocyte colony-stimulating factor is allowed to use for neutropenia event. Patients will be discontinued from study treatment for the following reasons: disease progression; unacceptable toxicities; patient's refusal to continue. Radiological examinations (according to the RECIST 1.1 criteria) at baseline will be repeated for tumor response evaluation following every two cycles of chemotherapy. Patients will be followed up to 30 days after the last dose of study chemotherapy, and then every 3 months. Blood samples \[8ml with ehylene diamine tetraacetic acid (EDTA) as anticoagulant each time\] will be collected at the time of baseline, tumor response evaluation every 2 cycles, and disease progression. Blood samples at baseline and disease progression are mandatory to be provided. Tumor samples collection at the time of baseline and/or disease progression is strongly recommended but not mandatory for this study.