Two‐year efficacy of SNK01 plus pembrolizumab for non‐small cell lung cancer: Expanded observations from a phase I/IIa randomized controlled trial

BACKGROUND: A previous trial showed that autologous ex‐vivo expanded NK cell (SNK01) treatment combined with pembrolizumab showed better efficacy than pembrolizumab monotherapy in advanced non‐small cell lung cancer (NSCLC). This study was a 2‐year follow‐up of that previous study to determine the long‐term efficacy of the combination treatment. METHODS: This trial included 20 patients with advanced NSCLC with a PD‐L1 tumor proportion score of 1% or greater who failed prior to front‐line platinum‐based therapy. The patients received pembrolizumab with low‐dose SNK01 (2 × 10(9) cells/dose) or high‐dose SNK01 (4 × 10(9) cells/dose), or pembrolizumab monotherapy. The primary study endpoint was overall survival (OS), and the secondary endpoint was progression‐free survival (PFS). RESULTS: Two patients were excluded following serious adverse events. Among the 11 patients who died, five were from the NK groups (41.6%, n = 5/12), and six received pembrolizumab monotherapy (100%, n = 6/6). The estimated 2‐year survival rate was 58.3% versus 16.7% (pembrolizumab plus SNK01 vs. pembrolizumab monotherapy). The hazard ratio of pembrolizumab plus SNK01 compared with pembrolizumab monotherapy was 0.32 (95% CI: 0.1, 1.08, p‐value: 0.066). Although the median PFS was significantly higher in the pembrolizumab plus SNK01 group than in the pembrolizumab alone group, OS and PFS did not differ statistically between patients who received low doses of NK cells and those who received high doses of NK cells. CONCLUSIONS: Autologous NK cells can enhance the long‐term OS and PFS for NSCLC. A larger study is needed to confirm this result. Clinical Research Information Service number: KCT0003463.