P1238: EFFICACY ANALYSIS OF PEGASPARGASE, GEMCITABINE, OXALIPLATIN, DEXAMETHASONE COMBINED WITH TISLELIZUMAB IN FIRST-LINE TREATMENT OF PLASMA EBV-DNA POSITIVE EXTRANODAL NK/T CELL LYMPHOMA

Abstract

Background: Positive circulating EBV-DNA is associated with a very poor outcome in Natural killer/T cell lymphoma (NKTCL). Efforts to further improve treatment of plasma EBV positive NKTCL are urgently needed. Aims: To investigate the clinical efficacy, plasma EBV-DNA load and safety of P-GEMOXD combined with anti-programmed death 1 (anti-PD-1) antibody Tislelizumab in first-line treatment of plasma EBV-DNA positive NKTCL. Methods: In this prospective, single-arm, phase 2 trial, we recruited patients aged 18–70 years with newly diagnosed NKTCL who were EBV-DNA positive in plasma in Henan People’s Hospital. Patients received four courses of P-GEMOXD plus Tislelizumab treatment (pegaspargase 2500U/m2 [day3], gemcitabine 800mg/m2 [day1 and 8]; oxaliplatin100 mg/m2[day1], dexamethasone 20mg/d [day1-4]; Tislelizumab 200mg /d [day9] every 21days). Thirteen patients were enrolled from January 2018 to August 2021 December, the median follow-up was 26 (12-46) months. The short-term and long-term clinical efficacy, load of EBV-DNA and adverse reactions were observed. Results: Among the 13 patients, there were 9 males and 4 females, the median age was 54 years old (range 25-64). After 4 courses of treatment, 10 patients (76.9%) had complete response, 3 patients (23.1%) had partial response, and the objective response rate (ORR) was 100%. The 2-year progress-free survival (PFS) rate was 76.9%, and the 2-year overall survival (OS) rate was 85.7%. Among them, there were 6 patients with advanced stage (III and IV), 4 patients (66.7%) had complete response, 2 patients (33.3%) had partial response, 5 patients (83.3%) plasma EBV-DNA converted negative; the 2-year progression-free survival (PFS) rate was 66.7%, and the 2-year overall survival (OS) rate was 66.7%. Treatment-related AEs of any grade occurred in 84.6% (11/13) of all patients. The main adverse reactions were albumin reduction (8/13), fibrinogen reduction (9/13), autoimmune diseases (3 cases：1 case of hypopituitarism， 1 case of Hashimoto’s thyroiditis, and 1 case spondylitis). Summary/Conclusion: P-GEMOXD plus Tislelizumab can significantly improve the prognosis of patients with NKTCL, improve the rate of plasma EBV-DNA negative conversion, and the adverse reactions can be well tolerated.