Extranodal natural killer/T cell lymphoma, nasal type (ENKL) is a highly aggressive tumor with relatively poor prognosis. In this prospective study, we investigated the efficacy and toxicity of a novel GDP-ML regimen (combined gemcitabine, cisplatin, dexamethasone, methotrexate, and pegaspargase) as front-line treatment in newly diagnosed ENKL. Eligible newly diagnosed stage I/II ENKL patients received sandwich chemoradiation therapy. Patients with stage III/IV disease received an initial 4 cycles of GDP-ML regimen. After 4 cycles, responding patients continued to receive either autologous transplantation or additional two courses of GDP-ML. A total of 44 patients were enrolled with a median follow-up of 26 months. The overall response rate (ORR) were 78.6% for the whole cohort, 84.6% for stage I/II, and 66.7% for stage III/IV, and corresponding complete remission (CR) rates were 61.9%, 76.9%, and 33.3%. The 1- year and 2- year progression-free survival (PFS) rates were 69.3% and 62.9%, and 1- year and 2-year overall survival (OS) rates were 76.5% and 67.4%, respectively. Patients with stage I/II disease showed better 2-year OS rate compared with stage III/IV patients (88.1% vs. 33.2%, p < 0.001). Patients who achieved CR had significantly better 2-year OS rate compared with non-CR patients (90.8% vs. 24.5%, p < 0.001). The main adverse event was hematologic toxicity. Grade 3/4 neutropenia occurred in 59.1% of patients. These results indicate that GDP-ML is an effective and well-tolerated induction regimen with newly diagnosed ENKL patients. This clinical trial was registered on www.chictr.org.cn (ChiCTR-ONC-12002055).
Keywords: Extranodal natural killer/T cell lymphoma; GDP; Methotrexate; Overall response rate; Overall survival; Pegaspargase.