No abstract

This study aimed to assess the efficacy and safety of treatment with avelumab, an anti-programmed death ligand 1 (PD-L1) antibody, in patients with relapsed or refractory extranodal natural killer (NK)/T-cell lymphoma (ENKTL). In this phase II trial, 21 patients with relapsed or refractory ENKTL were treated with 10 mg/kg of avelumab on days 1 and 15 of a 28-day cycle (ClinicalTrials.gov Identifier: NCT03439501). The primary end point was the complete response (CR) rate based on the best response. Targeted sequencing and immunohistochemistry were performed using pretreatment tumor tissue, and blood samples were drawn pre- and post-treatment for measurement of cytokines and soluble programmed cell death protein 1 (PD1), PD-L1, and PD-L2. The CR rate was 24% (5/21) and the overall response rate was 38% (8/21). Although nonresponders showed early progression, five responders currently continue to receive treatment and have maintained their response. Most treatment-related adverse events were grade 1 or 2; no grade 4 adverse events were observed. Treatment responses did not correlate with mutation profiles, tumor mutation burden, serum levels of cytokines, or soluble PD1/PD-L1 and PD-L2. However, the response to avelumab was significantly associated with the expression of PD-L1 by tumor tissue (P = 0.001). Therefore, all patients achieving CR showed high PD-L1 expression, and their tumor subtyping based on PD-L1 expression correlated with treatment response. In conclusion, avelumab showed single-agent activity in a subset of patients with relapsed or refractory ENKTL. The assessment of PD-L1 expression on tumor cells might be helpful for identifying responders to avelumab.

Extranodal natural killer/T cell lymphoma (ENKTL), nasal type, presents predominantly as a localized disease involving the nasal cavity and adjacent sites, and the treatment of localized nasal ENKTL is a major issue. However, given its rarity, there is no standard therapy based on randomized controlled trials and therefore a lack of consensus on the treatment of localized nasal ENKTL. Currently recommended treatments are based mainly on the results of phase II studies and retrospective analyses. Because the previous outcomes of anthracycline-containing chemotherapy were poor, non-anthracycline-based chemotherapy regimens, including etoposide and l-asparaginase, have been used mainly for patients with localized nasal ENKTL. Radiotherapy also has been used as a main component of treatment because it can produce a rapid response. Accordingly, the combined approach of non-anthracycline-based chemotherapy with radiotherapy is currently recommended as a first-line treatment for localized nasal ENKTL. This review summarizes the different approaches for the use of non-anthracycline-based chemotherapy with radiotherapy including concurrent, sequential, and sandwich chemoradiotherapy, which have been proposed as a first-line treatment for newly diagnosed patients with localized nasal ENKTL.