Durable Responses Using SNK01 Autologous Enhanced Natural Killer Cells and Pembrolizumab for Chemotherapy-Resistant Advanced Sarcoma: Case Reports, Review of Literature and Future Perspectives

Advanced or metastatic sarcoma is associated with an invariably fatal outcome. Two noteworthy cases of chemotherapy-resistant metastatic sarcoma with durable responses to SNK01 autologous enhanced natural killer cell therapy and pembrolizumab, an immune checkpoint inhibitor, are reported here. Single patient use of SNK01 and pembrolizumab was authorized by the United States Food and Drug Administration and a Central Institutional Review Board. After informed consent was obtained, Patient #1 with desmoplastic small round cell tumor and Patient #2 with radiation-induced chondrosarcoma received SNK01 2x109 cells i.v. and 200 mg pembrolizumab i.v. every 3 weeks. Patient #1’s tumors gradually decreased in size, achieving a 47% partial response after which the patient underwent two surgical resections and achieved a sustained remission. Patient #2’s tumors gradually decreased in size, achieving a 38% partial response. Albeit a very small case study, the data suggest that SNK01 plus pembrolizumab may be a viable therapeutic option for patients with chemotherapy-resistant advanced sarcoma with manageable toxicity, and supports existing evidence that natural killer cells mediate a favorable response to immune checkpoint inhibitor therapy while reducing immune-related adverse events.