Final Report on Phase II Trial of L-Asparaginase Plus Concurrent Chemoradiotherapy Followed By Midle (Methotrexate, Ifosfamide, Etoposide, Dexamethasone, and L-asparaginase) Chemotherapy for Patients with Newly Diagnosed Stage I/II Extranodal NK/T-Cell Lymphoma, Nasal Type (2015)

Abstract Background We previously have shown that concurrent chemoradiotherapy (CCRT) followed by chemotherapy such as VIPD (etoposide, ifosfamide, cisplatin and dexamethasone) or VIDL (etoposide, ifosfamide, dexamethasone and L-asparaginase) is an effective treatment for the management of localized extranodal NK/T-cell lymphoma (ENKTL), nasal type. To further improve efficacy, we designed a new treatment protocol, MIDLE (methotrexate, ifosfamide, dexamethasone, L-asparaginase and etoposide), which incorporates tri-weekly administration of L-asparaginase during CCRT to reduce the probability of systemic progression and high dose methotrexate to intensify chemotherapy based on previous excellent outcomes of methotrexate-containing regimens such as SMILE (dexamethasone, methotrexate, ifosfamide, L-asparaginase, etoposide) and MLD (methotrexate, L-asparaginase, dexamethasone). Methods The treatment scheme of CCRT consisted of radiation 36-45 Gy and weekly administration of cisplatin 30 mg/m2 (total: 4 doses). During the CCRT, tri-weekly 4,000 IU of Escherichia coli L-asparaginase was administered intravenously (IV). The chemotherapy, MIDLE (methotrexate 3 g/m2 on day 1, etoposide 100 mg/m2, Ifosfamide 1000 mg/m2 on day 2-3, dexamethasone 40mg on day 1-4, and L-asparaginase 6000 IU/m2 IV on day 4, 6, 8, 10) was repeated every 28 days for two cycles. All patients provided informed written consents and this trial was registered at www.ClinicalTrials.gov(NCT01238159). Results Twenty-eight patients with stage IE/IIE ENKTL were enrolled, and the median age was 51 years (range, 30-77 years). Twenty four patients were male while only four patients were female. Twenty-two patients had stage IE and six IIE disease. Twenty four were classified as low risk group and the other four intermediate group according to PINK-E (Kim SJ et al., EHA 2015 S110). All but two patients completed CCRT, which resulted in 85.7% of overall response rate including 16 complete responses (57.1%) and 8 partial responses (28.6%). One showed stable disease (SD) and the other one showed progressive disease (PD) with development of new distant lymph node involvement after CCRT. Grade 3 or 4 hematologic toxicity was not common. Only two patients experienced G3 neutropenia during or after CCRT. However, grade 3 non-hematologic toxicities were noted including bilirubin elevation (n = 3), mucositis (n = 1), anorexia (n=5) and nausea/vomiting (n = 11) Two could not complete CCRT according to the protocol due to G3 allergic reaction to L-asparaginase (n=1) and prolonged G3 mucositis (n=1). After the completion of CCRT, 23 out of 28 patients entered the MIDLE chemotherapy as five patients including one disease progression and four withdrawal during (n=2) or after (n=2) CCRT due to toxicities. All those who completed the planned two cycles of MIDLE chemotherapy achieved complete response after chemotherapy including those with PR (n=6) and SD (n=1) after CCRT. Three patients dropped out during or after their first cycle of MIDLE due to non-hematologic toxicities (recurrent G3 bilirubinemia (n=1), G3 increased creatinine (n=1), G5 infection (n=1)). The final complete response rate was 82% (23/28). It was associated with a significant rate of grade 3/4 neutropenia (n=21) and febrile neutropenia (n=10). Two patients experienced acute kidney injury (AKI) during the first cycle of MIDLE and one of them died of pneumonia complicated by sepsis. With a median follow-up of 46 months (95% confidence interval: 39 - 47 months), four patients progressed and five patients died with the estimated 3-year progression-free survival rate of 74.1% and overall survival rate of 81.5%. PINK-E could successfully stratify both time-to-progression (p=003) and overall survival (p=0.006) in this study. Conclusion L-asparaginase plus concurrent chemoradiotherapy followed by MIDLE chemotherapy may be an effective treatment strategy for stage I/II extranodal NK/T-Cell lymphoma, nasal type. However, higher numbers of patients were withdrawn during or after CCRT due to toxicity or poor tolerance than previous study. MIDLE chemotherapy was associated with high rate of G3 or 4 hematologic toxicities. Thus, this approach should be reserved for selected patients such as young fit but high risk of relapse. PINK-E can be a useful prognostic index for stage I/II extranodal NK/T-Cell lymphoma, nasal type. Disclosures No relevant conflicts of interest to declare.