A Prospective Phase II Trial of An L-Asparaginase Containing Regimen in Patients with Refractory or Relapsing Extra Nodal NK/T-Cell Lymphoma

Extra nodal NK/T-cell lymphoma, nasal type, is an EBV-related highly aggressive disease with a poor outcome, especially when disseminated or recurrent after radiotherapy. L-Asparaginase seems to have a particular efficacy in this disease (Jaccard, 2008, Ann oncol). Nineteen patients with relapsing or refractory extra nodal NK/T-Cell Lymphoma, nasal type, were included in a multicentric prospective phase II trial using the Aspametdex regimen (E coli-L-asparaginase (Kidrolase®) 6000 UI/m2 IM at day 2,4,6,8, methotrexate 3 gr/m2 at day 1 and dexamethasone 40 mg at day 1 to 4 with 3 weeks cycles). Patients below 65 years of age and with a good performance status received 3 cycles and, in case of good response, an intensive treatment with the BEAM regimen and stem cell rescue. Other patients received up to 6 cycles of the Aspametdex protocol. Patients with localized disease received irradiation if not performed before inclusion. The histology was centrally reviewed and EBV viremia was regularly and centrally monitored. The response after 3 cycles was the primary end point. There were 14 men and 4 women (1 patient was excluded after pathologic review), median age was 59.5 (45 to 76), 7 were primary refractory, 11 were in relapse, 6 were in stage IV. Median number of cycles was 3 (1 to 6). Three patients who had an allergic reaction with L-asparaginase received further courses of Erwinia-asparaginase (Erwiniase®) (n= 3). Toxicity related to L-asparaginase was mild, mainly brief leucopenia (n=2), elevation of alanine aminotransferase (n=2) and venous thrombosis (n=1). Response was documented in 17/18 patients, 10 patients were in complete remission (CR) after treatment with L-asparaginase and 5 patients in partial remission. Five patients died of unrelated causes (n=1) or progression of disease (n=4). Thirteen patients are still alive with a median follow-up of 8 months (1 to 29), 5 responding patients progressed at 4, 5, 8, 8 and 22 months after treatment. Six patients are in persistent CR, 2 of these patients had received high dose therapy with autologous stem cell transplant and 1 patient received irradiation after L-asparaginase treatment. These data confirm the excellent activity of L-asparaginase-containing regimens in extranodal NK/T-cell lymphoma. This must be known because of the very poor prognosis of patients with disseminated or relapsing disease with conventional chemotherapy. First-line L-asparaginase combination therapy for extranodal NK/T-cell lymphoma should be tested in prospective trials.