L-Asparaginase Monotherapy in Patients with Relapsed or Refractory Extranodal NK/T-Cell Lymphoma, Nasal Type: Results of A Phase II Study.

Abstract 2730 Introduction: Recently, L-asparaginase-based combination chemotherapy was found to be effective in salvage treatment in patients with relapsed or refractory extranodal NK/T-cell lymphoma, nasal type. To explore the single-agent activity of L-asparaginase, we conducted a single-institute, prospective phase II study. Methods: Patients with relapsed or refractory extranodal NK/T-cell lymphoma, nasal type were eligible for enrollment regardless of prior treatment. L-asparaginase monotherapy (6000 U/m2 on days 1 to 7) was administered as the protocol treatment and repeated every 3 weeks for at most 8 cycles. For responding patients, the decision to proceed with hematopoietic stem-cell transplantation was made at the discretion of treating physicians. The primary endpoint was the best objective response after L-asparaginase. Results: A total of 40 patients were enrolled and treated with L-asparaginase for a median of 5 cycles (range, 1 – 8). The patient characteristics were shown in Table 1. Half of the patients had stage IV disease at enrollment and the vast majority (18 patients) presented with disseminated cutaneous and soft-tissue involvement. Thirty-seven patients (92.5%) had prior exposure to systemic chemotherapy and 14 of them (37.8%) received more than 1 line. The overall response rate was 82.5%. The complete response (CR) and partial response (PR) rates were 40% and 42.5%, respectively. The incidence of adverse events was shown in Table 2. In short, anemia, neutropenia, hypoalbuminemia, nausea and liver-related disorders were common toxicities, which were usually mild and manageable. No grade 4 adverse events and treatment-related mortality were observed. Five patients (12.5%) developed allergic reaction to L-asparaginase and 3 of them had to withdraw from the study since L-asparaginase re-challenge with prophylactic antiallergic agents was unsuccessful. After a median follow-up time of 31.6 months (range, 21.9 – 41.3), the median progression-free survival (PFS) was 12.8 months and median overall survival (OS) was not reached. Response status (CR, PR or no response) after L-asparaginase had a significant impact on either PFS (Figure 1) or OS (Figure 2). Moreover, its prognostic value was confirmed in the multivariate analysis. Conclusions: L-asparaginase demonstrated a high single-agent activity in salvage setting for patients with extranodal NK/T-cell lymphoma, nasal type. The first-line L-asparaginase-containing chemotherapy regimen warrants urgent investigation. Disclosures: Off Label Use: L-asparaginase, which was used in our study for NK/T-cell lymphoma, is approved to treat acute lymphocytic leukemia by US and Chinese FDA.