Keytruda as monotherapy is indicated for the first line treatment of metastatic non small cell lung carcinoma in adults whose tumours express PD L1 with a ≥ 50% tumour proportion score (TPS) with no EGFR or ALK positive tumour mutations.

A 67-year-old woman presented in 2007 with a large BCC of the skin...Pembrolizumab (anti-PD-1) was administered at 2 mg/kg IV every 3 weeks...CT scans performed 4 months into therapy demonstrated a partial response (PR) to therapy...Immunohistochemical evaluation of the patient’s pre-treatment BCC demonstrated PD-L1 expression on immune cells...Approximately 50% of the lymphocytes present expressed PD-1.