Efficacy of pegaspargase, etoposide, methotrexate and dexamethasone in newly diagnosed advanced-stage extra-nodal natural killer/T-cell lymphoma with the analysis of the prognosis of whole blood EBV-DNA

Extra-nodal natural-killer (NK)/T-cell lymphoma (ENKTL) is an aggressive disease common in Asia but rare in the West. More than two-thirds of persons have stage-I/II disease of the upper aero-digestive tract. 1 – 3 These persons often respond to radiation therapy with or without anti-cancer drugs but relapse is common. 4,5 Anthracycline-based regimens such as CHOP (cyclo-phosphamide, doxorubicin, vincristine and prednisone) are often used to treat advanced-stage disease but are ineffective with overall survival (OS) less than a year. 3 Recently, L -asparaginase-based regimens were shown to be more active. 6 – 8 The SMILE regimen ( L -asparaginase, etoposide, methotrexate, ifosfamide and dexamethasone) regimen is reportedly effective in newly diagnosed persons with advanced-stage disease. 7,8 A regimen of modi ﬁ ed SMILE was also reported to be effective by Yang et al. 6 We tested a regimen of PEMD (pegaspargase, etoposide, methotrexate and dexamethasone) in 32 newly diagnosed advanced-stage subjects with ENKTL. Thirty-two consecutive subjects with newly diagnosed advanced-stage (stages III – IV) ENKTL were prospectively studied from July 2010 to December 2015. The study was approved by the Ethics Committee of the First Af ﬁ liated Hospital of Nanjing Medical University. Subjects (32 patients) gave written informed consent in accordance with the Declaration of Helsinki. Biopsies were reviewed by ⩾ 2 experienced pathologists and diagnosis was based on WHO criteria

Extra-nodal natural-killer (NK)/T-cell lymphoma (ENKTL) is an aggressive disease common in Asia but rare in the West. More than two-thirds of persons have stage-I/II disease of the upper aero-digestive tract. [1][2][3] These persons often respond to radiation therapy with or without anti-cancer drugs but relapse is common. 4,5 Anthracycline-based regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) are often used to treat advanced-stage disease but are ineffective with overall survival (OS) less than a year. 3 Recently, L-asparaginasebased regimens were shown to be more active. [6][7][8] The SMILE regimen (L-asparaginase, etoposide, methotrexate, ifosfamide and dexamethasone) regimen is reportedly effective in newly diagnosed persons with advanced-stage disease. 7,8 A regimen of modified SMILE was also reported to be effective by Yang et al. 6 We tested a regimen of PEMD (pegaspargase, etoposide, methotrexate and dexamethasone) in 32 newly diagnosed advanced-stage subjects with ENKTL.
Thirty-two consecutive subjects with newly diagnosed advanced-stage (stages III-IV) ENKTL were prospectively studied from July 2010 to December 2015. The study was approved by the Ethics Committee of the First Affiliated Hospital of Nanjing Medical University. Subjects (32 patients) gave written informed consent in accordance with the Declaration of Helsinki. Biopsies were reviewed by ⩾ 2 experienced pathologists and diagnosis was based on WHO criteria. 1 Baseline clinical variables including age, sex, Ann Arbor stage, serum lactate dehydrogenase, blood Epstein-Barr virus (EBV)-DNA levels (EBV-DNA copy number in whole blood was quantified by a real-time PCR based on the amplification of EBNA1 gene with the cut-off value of 5000 copies/ ml), B-symptoms, extra-nodal sites of disease, Eastern Cooperative Oncology Group (ECOG) performance score, bone marrow involvement, distant lymph-node involvement, International Prognostic Index (IPI) scores and prognostic index of natural killer lymphoma (PINK). 9 pegaspargase, etoposide, methotrexate and dexamethasone was given as follows: methotrexate, 3.0 g/m 2 i.v. over 6 h on day 1; etoposide, 100 mg/m 2 i.v. on days 2-4; dexamethasone, 40 mg i.v. on days 1-4; pegaspargase, 2500 U/m 2 i.m. on day 2. Subjects received 4-6 cycles of PEMD every 3 weeks. Patients could receive autologous or allogeneic hematopoietic stem cell transplantation after achieving complete remission or partial remission. The decision was made according to the discretion of the treating physician, mainly on the basis of the patient's age, comorbidities, economy and wishes.
Response criteria are reported using standard criteria. 10 Subjects were evaluated after three cycles of PEMD, after completing PEMD and every 3 months for 2 years thereafter. Responses were classified as complete response (CR), unconfirmed CR (CRu), partial response (PR), stable disease (SD) and progressive disease (PD). Physical exam and laboratory tests were used to evaluate adverse reactions and toxicities. Toxicities were graded according to the National Cancer Institute Common Toxicity Criteria, version 3.0.
Primary co-endpoints were response and survival. Overall response rate (ORR) was defined as the rate of CR/CRu and PR. Progression-free survival (PFS) was defined as the interval from study-entry to first progression. OS was defined as interval from study-entry to death from any cause. Secondary endpoints were proportion of subjects completing planned therapy (4-6 cycles of PEMD regimen) and frequencies of adverse events. Follow-up was through August 2016. Kaplan-Meier method was used to calculate PFS and OS. The log-rank test was used to analyze survival differences between the cohorts. Statistical analyses were performed using MedCalc for Windows, version 12.0.4.0 (MedCalc Software, Mariakerke, Belgium). P-values o 0.05 were considered significant.
Among all the 32 patients, four patients (patients 1-4) experienced early death. Therefore, no dynamic quantitative changes in EBV-DNA with therapy were observed for these four patients. The dynamic continuous quantitative changes of all the other 10 pretreatment EBV-DNA-positive and all 18 EBV-DNAnegative patients with therapy, which were classified as CR/CRu, PR and no response (NR, included SD and PD), were shown in Figure 1. The three pretreatment EBV-DNA-positive patients (patients 4-6) who experienced PD at the mid-therapy had reelevated EBV-DNA levels ( Figure 1a). Among the seven pretreatment EBV-DNA-positive patients who achieved more than PR at the end of the therapy, three patients who experienced PD after the completion of the PEMD regimen also had re-elevated EBV-DNA levels (Figure 1b). One patient (patient 16) had re-elevated EBV-DNA levels among the two EBV-DNA-negative patients (patients 15 and 16) who had PD at the mid-therapy (Figure 1c). Among the 16 EBV-DNA-negative patients who achieved more than PR at the end of the therapy, two patients (patients 20 and 21) who experienced PD after the completion of the PEMD regimen also had re-elevated EBV-DNA levels (Figure 1d).
There is no standard therapy for ENKTL. Most data are from retrospective analyses and small prospective series. Anthracyclinecontaining regimens have response rates of 40-60% with high subsequent failure rates. 11 SMILE is the most studied protocol for advanced disease. In a phase-2 study in 20 subjects with advanced disease ORR was 80% (95% CI 56-94%) and 2-year PFS and OS about 45%. 7 However, the significant toxicities that grade-4 neutropenia were occurred in 92% patients and serious infections
Circulating EBV-DNA in blood is derived from necrotic or apoptotic tumor cells, and thus viral DNA in the whole blood or plasma is strongly associated with survivals and treatment outcomes in patients with ENKTL which have been confirmed in many studies. 9,13,14 Similar results were also observed in the present study specially for advanced ENKTL patients who were treated with PEMD regimens. Furthermore, the amount of circulating viral DNA might show the burden and replication of tumors, and it might be undetectable in patients with small tumor burdens or those in whom proliferation is less active. Therefore, the dynamic quantitative changes in EBV-DNA with therapy were also observed in the present study. Patients who experienced PD always had re-elevated EBV-DNA levels in the blood. Therefore, circulating EBV-DNA level was an important prognostic and monitoring tumor markers, which has been added in the prognostic index for natural killer lymphoma (PINK-E) reported by Kim et al. 9 In conclusion, PEMD is safe and effective in persons with newly diagnosed advanced-stage ENKTL, especially for those not well-fit patients. Circulating EBV-DNA levels is an important prognostic and monitoring marker for advanced-stage ENKTL patients who treated with PEMD regimen. Larger prospective studies are needed to more precisely define toxicities and estimate efficacy and to compare PEMD with other regimens.