Use of PD-1 blockade in refractory/relapsed natural killer T-cell lymphomas: a systematic review and synthesis of case reports.

Natural killer/T-cell lymphoma (NK/T-cellL) is an aggressive non-Hodgkin's lymphoma with limited treatment options for patients who experience disease progression or recurrence after second-line treatment. The use of new therapies, such as pembrolizumab, which involves immune checkpoint blockade mechanisms, is proposed. This systematic review followed the MOSE guidelines and searched PUBMED/MEDLINE, EMBASE, and Scopus databases. Fourteen articles were found, reporting on the use of pembrolizumab anti PD-1 in NK/T-cellL patients. The objective response rate was 84.50%, with disease-free survival ranging from two to 48 months. The complete response rate was 61.6%, and the quality of the reported studies was evaluated to be of high and moderate confidence bias levels in case reports and high bias in clinical trials. Pembrolizumab and others anti PD-1 are treatment options for refractory/recurrent NK/T-cellL, regardless of PD-L1 expression, with good short- and long-term results and low adverse events.