Pembrolizumab in First Line Treatment of Advanced NSCLC Patients With PD-L1 Low Tumors.

Approximately 65 subjects with PD-L1 low (PD-L1Lo), EGFR wt, EML4/ALK fusion negative NSCLC will be enrolled in this trial for examination of the biological characteristics associated to efficacy and safety of Pembrolizumab. Subjects will receive Pembrolizumab iv at dose of 200 mg every three weeks. Subjects will be evaluated every 9 weeks (63 +/- 3 days) with radiographic imaging to assess response to treatment. Subjects will continue with the assigned study treatment until RECIST-defined progression of disease, unacceptable toxicity or consent withdrawal. Treatment with Pembrolizumab will continue until two years of therapy have been administered, documented disease progression, unacceptable adverse event(s), intercurrent illness that prevents further administration of treatment, investigator's decision to withdraw the subject, subject withdraws consent, pregnancy of the subject, noncompliance with trial treatment or procedure requirements, or administrative reasons. Pembrolizumab treated subjects who obtain a confirmed Complete Response (CR) per RECIST 1.1 may consider stopping trial treatment. These subjects may be eligible for re-treatment with Pembrolizumab after they have experienced radiographic disease progression at the discretion of the investigator, this re-treatment will be the Second Course Phase.