KEYNOTE-012 was a phase Ib, multicohort study designed to investigate efficacy and safety of pembrolizumab in advanced solid tumors. Results from the subset of patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) from the Asia-Pacific region are reported. Patients with recurrent/metastatic HNSCC, measurable disease (RECIST version 1.1), and ECOG performance status (PS) 0-1 were eligible for enrollment in the HNSCC expansion cohort. Patients received pembrolizumab 200 mg every 3 weeks. Response was assessed every 8 weeks. Co-primary end-points were safety and overall response rate (RECIST version 1.1, central review). Secondary end-points included overall survival and response duration. Patients enrolled at any of the five centers throughout the Asia-Pacific region were included in these analyses. Twenty-six patients with HNSCC from the Asia-Pacific region received pembrolizumab. The median age was 62 years, 65% of patients had ECOG PS 1, and 62% had received two or more prior therapies for recurrent/metastatic disease. Sixteen (62%) patients experienced a treatment-related adverse event of any grade, including two (8%) patients who experienced one or more events of grade 3 severity. No treatment-related deaths occurred. The overall response rate was 19% (95% confidence interval, 7%-39%). After a median follow-up of 12 months (range, 2-21 months), a median response duration was not reached (range, 6 to 17+ months); four of five responses lasted ≥6 months. Median overall survival was 11.6 months (95% confidence interval, 4.7-17.7 months). Pembrolizumab was well tolerated and had durable antitumor activity in patients with HNSCC from the Asia-Pacific region. (Trial registration no. NCT01848834.).