Natural Killer Cell Lymphoma Research Articles

Extracellular Vesicles Secreted from Daratumumab Resistant Cells Promote Resistance and Proliferation of Daratumumab Sensitive Cells, Possibly through the Transfer of miRNA Cargo

Multiple Myeloma (MM) is the second most common hematologic malignancy and remains incurable. Daratumumab (dara) is a potent anti-CD38 monoclonal antibody used for MM treatment, but responses are heterogeneous, and resistance is inevitable. There is hence an urgent need for identification of biomarkers to predict responses and in-depth characterisation of mechanisms of resistance. We have previously demonstrated that the exosome biogenesis pathway plays a significant role in the survival of dara resistant (dara R) cell lines. Here, we highlight that the enriched expression of exosome pathway proteins reported in dara R cell lines is not detected in Lenalidomide or Bortezomib-resistant cell lines, or in other monoclonal antibody resistant cell lines such as anti-CD20 (Rituximab)-resistant cell lines, thus indicating that this mechanism is unique to daratumumab resistance. Coculture of dara sensitive (dara S) cell lines with dara R cell lines separated by a cell-impermeable transwell insert promoted cell proliferation and reduced response to dara treatment in dara S cell lines thereby suggesting a potential role for extracellular vesicles (EVs) secreted by dara R cells in mediating these responses. In this study, we seek to investigate the role of EVs secreted by dara R cells, in particular, that of EV-derived miRNAs in the tumour microenvironment which can help predict and mediate dara resistance. We have originally described the establishment of three dara R cell lines in Natural Killer T-cell Lymphoma (NKTL), T-cell acute lymphoblastic leukaemia (T-ALL) and MM via long-term exposure to increasing concentrations of dara. To assess the specific role of EVs in mediating resistance, we isolated and purified EVs from the media of dara R cell lines and added it to the culture of dara S cells. To confirm uptake of dara R EVs by sensitive cell lines, EVs isolated from resistant cell lines were stained with PKH26 and characterised by binding to CD81 and CD63 beads via flow cytometry. Uptake of dara R EVs by dara S cell lines was confirmed through flow cytometry and confocal microscopy. We observed that uptake of dara R EVs directly promote proliferation and reduced cytotoxic response to dara treatment in dara S cells. Next, we assessed the effect of inhibiting dara R EV secretion by applying Neticonazole and Ketoconazole, prior to coculture of resistant and sensitive cell lines. Interestingly, coculturing azole-treated resistant cell lines with sensitive cell lines mitigated the increase in proliferation and dara resistance. Exosomal miRNAs are known to play a pivotal role in regulating cellular pathways driving cancer cell resistance and survival. To evaluate the potential role of EV-derived miRNA cargo, we first extracted miRNAs from the EVs purified from dara R and dara S cell lines and then performed an miRNA profiling screen with the PanoramiR panel (MiRXES) which targets 376 miRNAs expertly curated from miRBase 22, HMDD 3.2 and The Cancer Genome Atlas. We discovered that EVs derived from resistant cell lines expressed higher levels of proliferative miRNAs, miR-155 and miR-181a. These findings were validated through qPCR, confirming the increased expression of these miRNAs in both resistant cell lines and EVs derived from resistant cell lines. We also observed a concomitant downregulation of mir-155 target genes such as BACH1, JARID2 and SMAD5 in the resistant cell lines. This positive observation led us to extend the study into the clinic. Extracellular vesicles were isolated from the plasma fraction of bone marrow samples obtained from 17 patients with MM prior to treatment with dara based combinations either in the upfront or relapsed setting. miRNA extraction was performed and samples evaluated by miRNA sequencing. We found that the EVs from patients with a progression free survival (PFS) of less than 2 years after dara based therapy (dara R patients) had an enrichment of mir-155 and mir-181a as compared to those with a PFS longer than 2 years. These data align with our findings in the cell lines and suggest that these miRNAs may be utilised as potential biomarkers for daratumumab resistance. We are currently elucidating the biological basis for dara resistance mediated by these miRNAs. A deeper understanding of the mechanisms involved may pave the way for clinical evaluation of EV- directed therapeutics to overcome dara resistance.

A Retrospective Study on the Efficacy and Safety of Chidamide As a Maintenance Therapy for Peripheral T-Cell Lymphoma

Background: Peripheral T-cell lymphomas (PTCLs) are a set of rare and highly heterogeneous tumors of non-Hodgkin's lymphoma (NHL) with inferior outcomes. Chidamide is a novel benzamide class of histone deacetylase (HDAC) inhibitor (HDACi) that was approved by the Chinese Food and Drug Administration in 2014 for the treatment of relapsed or refractory (R/R) PTCL patients. This study aimed to assess the efficacy and safety of chidamide as a maintenance therapy after induction or salvage treatment in patients with PTCLs. Methods: The clinical data of 58 patients with different PTCL subtypes who received chidamide as a maintenance therapy after first-line or salvage treatment were collected. Progression-free survival (PFS), overall survival (OS), and safety were analyzed. Results: Fifty-eight patients enrolled in our study between January 2015 and July 2022, of whom 39 patients received chidamide as a maintenance therapy after first-line treatment and 19 patients after salvage treatment. All patients started chidamide maintenance after reaching at least partial response (PR). The median age was 66 (29-83) years. Patients with angioimmunoblastic T-cell lymphoma (AITL) represented the largest subgroup (34, 58.6%), followed by PTCL, not otherwise specified (PTCL-NOS) (10, 17.2%), anaplastic large cell lymphoma (ALCL) (8, 13.8%), NK/T cell lymphoma (NKTCL) (5, 8.6%) and monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) (1, 1.7%). Thirty-four (58.6%) patients were stage III-IV, and 38 (65.5%) patients had intermediate or high risk (prognostic index for T-cell lymphoma (PIT) 2-4). Among the 39 patients who underwent chidamide maintenance after first-line treatment, 30/39 (76.9%) patients began maintenance after reaching complete response (CR) and 9/39 (23.1%) after achieving PR. Notably, 8/9 (88.9%) patients achieved CR from PR during maintenance treatment, with a median time of 6 (3-12) months. A total of 11/39 (28.2%) patients experienced disease progression during the maintenance treatment, and their median duration of remission was 6 (3-13) months. Among them, 2 patients experienced disease progression 2 to 3 months after drug withdrawal due to COVID-19 infection. A total of 19 patients who received maintenance treatment after salvage therapy, 9 (47.4%) received maintenance therapy after CR and 10 (52.6%) received maintenance therapy after PR. Among them, 9/19 (47.4%)had disease progression and their median duration of remission was 16 (2-25) months. The remaining 10 patients (8 CR and 2 PR) were still undergoing maintenance treatment and follow-up. The median maintenance treatment time for all patients was 16 (1-72) months, and the median maintenance dose was 20 (15-30) mg twice weekly. The median follow-up time was 39 (2-79) months, the median PFS was 33 months, and the median OS had not been reached (Figure 1 a, b) for all patients. The median PFS and OS of the patients who received first-line maintenance therapy were not reached, which were significantly better compared to patients who received chidamide as salvage treatment maintenance (the median PFS and OS were 7 and 67 months, P < 0.001, P = 0.009, respectively) (Figure 1 c, d). There was no statistical difference in PFS and OS among the different pathological subtypes, but AITL seemed to achieve better PFS (Figure 1 e, f). The most common toxicities were hematologic toxicities, including neutropenia (42, 72.4%), anemia (23, 39.7%), and thrombocytopenia (29, 50.0%), followed by fatigue (35, 60.3%), anorexia (31, 53.4%), liver dysfunction (10, 17.2%), and pneumonia (4, 6.9%). Most adverse events were grade 1 or 2, and the grade 3‒4 adverse events were neutropenia (15/42), thrombocytopenia (7/29), fatigue (1/35), and pneumonia (2/4). Twelve (20.7%) patients underwent a dose reduction and three patients discontinued treatment (two patients with severe pulmonary infections, and one patient had intolerable fatigue) due to adverse events. One patient stopped maintenance treatment after taking chidamide for 10 months for financial reasons and he is still in follow-up. Conclusion: The findings of this study showed that patients with chidamide maintenance therapy had a better PFS and OS with a manageable safety profile, especially as the first-line maintenance therapy. We conclude that chidamide can be used as a maintenance treatment to improve the survival of patients with PTCLs.

Phase II Study of Lenalidomide Maintenance after Salvage Therapy for Relapsed or Refractory Peripheral T-Cell Lymphomas

Introduction Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas. Their prognoses are still poor especially after they relapse or become refractory to the first-line treatment. Although salvage chemotherapy followed by autologous stem cell transplantation (ASCT) could be used for those relapsed or refractory patients, a substantial number of patients relapse even after ASCT. Furthermore, ASCT is not always possible because elderly or frail patients are not eligible for high-dose chemotherapy followed by ASCT. Thus, there are limited treatment option for patients who failed after ASCT or ineligible for ASCT because there is no established salvage treatment strategy and the impact of novel therapies in previous trials is unknown. Lenalidomide is widely used for the treatment of B-cell lymphomas as well as multiple myeloma, however, there are a few data about its efficacy in patients with PTCLs. Considering the mode of action is related with the immune modulatory effect on tumor microenvironment, lenalidomide might have a role in the management of relapsed or refractory PTCLs. Thus, we hypothesized that the use of lenalidomide as a maintenance therapy for patients who achieve response after salvage therapy might produce survival benefit comparable to that of ASCT after salvage therapy. Methods This is a prospective, open-labeled, single-arm, multi-center phase II study for relapsed or refractory PTCLs. The inclusion criteria are as follows: 1) Patients should have relapsed or refractory disease after at least one-line of prior chemotherapy; 2) Patients should not be eligible for ASCT; 3) Patients should have any subtypes of PTCLs including PTCL-not otherwise specified (PTCL-NOS), angioimmunoblastic T-cell lymphoma (AITL), anaplastic lymphoma kinase (ALK)-positive or -negative anaplastic large-cell lymphoma (ALCL), extranodal NK/T-cell lymphoma (ENKTL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), hepatosplenic T-cell lymphoma (HSTL), and mycosis fungoides (MF). When patients eligible for the study achieve complete response (CR) or partial response (PR) after four cycles of any kinds of salvage chemotherapy, they can receive lenalidomide as a maintenance therapy. One cycle is 28 days consisting of lenalidomide 25 mg (day 1 - day 21). The treatment can be repeated until progression or the occurrence of intolerable toxicities (up to 2 years). The primary end point is 1-year progression-free survival, and the target rate is 35%. Results A total of 58 patients were enrolled between February 2019 and May 2023. The median age was 62 years (range: 20 - 83 years) and male was dominant (male: 35, female: 23). Patients who failed after ASCT or could not undergo ASCT due to their health status participated in the study. Patients with AITL (n = 23) and PTCL-NOS (15) accounted for 66% of patients whereas other subtypes included ENKTL (n = 4), ALK-negative ALCL (n = 3), MEITL (n = 3), HSTL (n = 2) and MF (n = 7). Prior to the maintenance therapy with lenalidomide, their disease status was CR (n = 22, 38%) and PR (n = 36, 62%). At the median follow-up of 20.7 months (95% CI: 17.7 - 23.7 months), seven patients completed the planned treatment of 2 years, and three patients withdrew their informed consents. Disease progression was documented in 21 patients during the maintenance and the other 20 patients discontinued the treatment due to their adverse events. At the time of analysis, seven patients were maintaining their treatments. Out of 36 patients with PR before maintenance, five patients achieved CR and 13 patients showed PR. However, 18 patients showed disease progression during maintenance. On the other hand, only three patients showed disease progression among 22 patients with CR prior to lenalidomide maintenance. Thus, 1-year PFS after enrollment was 49% and the median OS was (34.1 months, 95% CI: 7.9 - 18.6 months, Figure 1). The most common hematologic toxicities were neutropenia and thrombocytopenia; thus, dose-reduction should be done in patients with grade 4 hematologic toxicity. The most frequent non-hematologic toxicities included skin rash (40%), nausea (35%), and diarrhea (20%) however, they were manageable. Conclusions The lenalidomide maintenance might be a feasible and effective treatment approach for patients with relapsed or refractory PTCLs who are ineligible for ASCT or intensive consolidation chemotherapy.

Molecular and clinicopathological features of granzyme B-negative extranodal NK/T-cell lymphoma

Extranodal NK/T-cell lymphoma (ENKTL) generally expresses cytotoxic molecules, including granzyme B (GZMB), T-cell-restricted intracellular antigen-1 (TIA-1), and perforin; however, the expression of these molecules varies across cases. We performed gene expression profiling and identified unique biological and clinicopathological features of GZMB-negative ENKTL. We reviewed the clinicopathological characteristics of 71 ENKTL samples. Gene expression profiling on nine ENKTLs using multiplexed, direct, and digital mRNA quantification divided ENKTLs into Groups A (n = 7) and B (n = 2) through hierarchical clustering and t-distributed stochastic neighbor embedding. Group B was characterized by downregulation of genes associated with IL6-JAK-STAT3 signaling and inflammatory responses. GZMB mRNA expression was significantly downregulated in Group B. GZMB protein expression was evaluated with immunohistochemistry in all 71 ENKTLs, and expression data of Tyr705-phosphorylated STAT3 (pSTAT3) and MYC from our previous study was utilized. T-cell receptor gamma (TRG) gene rearrangement in the selected samples was also assessed using PCR. GZMB expression was higher in pSTAT3-positive (p = 0.028) and MYC-positive (p = 0.014) ENKTLs. Eighteen percent (13/71) of all ENKTLs were negative for GZMB (defined by positivity <10 %); patients with GZMB-negative ENKTLs were often in a higher clinical stage (p = 0.016). We observed no other correlations with clinical parameters or TRG rearrangement and no significant association between GZMB expression and survival. In conclusion, GZMB expression is highly heterogeneous in ENKTLs and is associated with the activation of the JAK-STAT3 pathway and higher MYC expression. GZMB-negative ENKTLs correlate with an advanced clinical stage, suggesting the potential utility of GZMB immunohistochemistry as a biomarker of ENKTL.

Extranodal NK/T-Cell Lymphoma Predominantly Composed of Anaplastic Cells: A Frequently Misdiagnosed and Highly Aggressive Variant.

Extranodal NK/T-cell lymphoma (ENKTL) is a non-Hodgkin lymphoma associated with the Epstein-Barr virus that primarily affects individuals in East Asia and indigenous populations in Central and South America. Morphologically, ENKTL typically consists of medium-sized cells or a combination of small and large cells. This report presents 10 cases characterized by predominantly anaplastic cells with diffuse expression of CD30, resembling anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK-negative ALCL) and demonstrating highly aggressive behavior. The cohort included 9 males and 1 female, ranging in age from 29 to 65 years (median age: 47y). Eight patients presented with nasal disease, while 2 had non-nasal disease. Five patients had stage I/II disease, and the remaining 5 had stage III/IV disease. Morphologically, necrosis was observed in 9 cases, angiocentric-angiodestructive growth in 3 cases, and pseudoepitheliomatous hyperplasia in 2 cases. Anaplastic cells predominated in all cases, with some displaying eccentric, horseshoe-shaped, or kidney-shaped nuclei (referred to as "Hallmark" cells). The morphology profile was monomorphic in 3 cases and polymorphic in 7 cases. Immunohistochemically, all cases tested positive for cytotoxic granule markers (TIA1 and granzymeB) and Epstein-Barr virus-encoded RNA. Cytoplasmic expression of CD3ε and CD56 was observed in 9 of 10 cases. Interestingly, most cases (7 of 8) exhibited variable expression of MuM1, ranging from 10% to 90%. All cases showed diffuse positivity for CD30 but were negative for ALK, resulting in 3 cases being initially misdiagnosed as ALK-negative ALCL. Compared with nonanaplastic cases, anaplastic cells predominant ENKTL had a significantly higher frequency of "B" symptoms, bone marrow involvement, hemophagocytic lymphohistiocytosis, and higher Ki67 proliferative index. These findings provide valuable information for pathologists, expanding their understanding of the cytologic spectrum of ENKTL. This rare variant of ENKTL, characterized by the predominance of anaplastic cells and diffuse CD30 expression, exhibits high aggressiveness and should be differentiated from ALK-negative ALCL. Awareness of this uncommon variant is crucial in preventing misdiagnosis and ensuring the timely initiation of therapy.

Single-Cell Analysis Reveals Malignant Cells Reshape the Cellular Landscape and Foster an Immunosuppressive Microenvironment of Extranodal NK/T-Cell Lymphoma.

Extranodal natural killer/T-cell lymphoma (NKTCL) is an aggressive type of lymphoma associated with Epstein-Barr virus (EBV) and characterized by heterogeneous tumor behaviors. To better understand the origins of the heterogeneity, this study utilizes single-cell RNA sequencing (scRNA-seq) analysis to profile the tumor microenvironment (TME) of NKTCL at the single-cell level. Together with in vitro and in vivo models, the study identifies a subset of LMP1+ malignant NK cells contributing to the tumorigenesis and development of heterogeneous malignant cells in NKTCL. Furthermore, malignant NK cells interact with various immunocytes via chemokines and their receptors, secrete substantial DPP4 that impairs the chemotaxis of immunocytes and regulates their infiltration. They also exhibit an immunosuppressive effect on T cells, which is further boosted by LMP1. Moreover, high transcription of EBV-encoded genes and low infiltration of tumor-associated macrophages (TAMs) are favorable prognostic indicators for NKTCL in multiple patient cohorts. This study for the first time deciphers the heterogeneous composition of NKTCL TME at single-cell resolution, highlighting the crucial role of malignant NK cells with EBV-encoded LMP1 in reshaping the cellular landscape and fostering an immunosuppressive microenvironment. These findings provide insights into understanding the pathogenic mechanisms of NKTCL and developing novel therapeutic strategies against NKTCL.

Pembrolizumab for Patients with Relapsed or Refractory Extranodal NK/T-Cell Lymphoma in Korea.

Programmed death-1 blockade with pembrolizumab has shown promising activity in relapsed/refractory (R/R) extranodal natural killer/T-cell lymphoma (NKTCL), but studies are limited, with small patient numbers. Thirteen institutes involved with the Consortium for Improving Survival of Lymphoma, a Korean lymphoma study group, collected the clinical data of 59 patients treated with pembrolizumab as salvage therapy between 2016 and 2022. The median age of the patients was 60 years (range, 22 to 87 years), and 76.3% had advanced Ann Abor stage disease. Pembrolizumab was given to 35.6%, 40.7%, and 23.7% of the patients as second-, third-, and fourth- or higher-line chemotherapy, respectively. The overall response rate was 40.7%, with 28.8% having complete response. The estimated 2-year progression-free survival (PFS) and overall survival rates for all patients were 21.5% and 28.7%, respectively; for responders, the rates were 53.0% and 60.7%, respectively. Although not statistically significant, Eastern Cooperative Oncology Group performance status ≥ 2 (hazard ratio [HR], 1.91; 95% confidence interval [95% CI], 0.93 to 3.94; p=0.078) and stage III or IV disease (HR, 2.59; 95% CI, 0.96 to 6.96; p=0.060) were associated with a trend toward shorter PFS in multivariate analysis. Grade 3 or 4 adverse events (AEs) were noted in 12 patients (20.3%); neutropenia (10.2%), fatigue (6.8%), and pneumonitis (5.1%) were most common AEs. In conclusion, while pembrolizumab had a modest effect on patients with R/R NKTCL, it may be a useful salvage therapy for patients with localized disease and good performance status.

Phase 2 Clinical Trial of Simultaneous Boost Intensity Modulated Radiation Therapy With 3 Dose Gradients in Patients With Stage I-II Nasal Type Natural Killer/T-Cell Lymphoma: Long-Term Outcomes of Survival and Quality of Life

The aim of this study was to investigate the treatment results and long-term quality of life in patients with early-stage extranodal natural killer/T-cell lymphoma who were prospectively treated with simultaneous boost intensity modulated radiation therapy (SIB-IMRT) with 3 dose gradients. Sixty patients with stage I-II nasal cavity natural killer/T-cell lymphoma (NKTCL) and Waldeyer's ring NKTCL were enrolled in a single-arm, prospective, phase 2 clinical trial from August 2011 to April 2015. All patients were treated with definitive radiation therapy combined with short-course induction chemotherapy. A newly designed SIB-IMRT scheme was uniformly adopted, with 54.6 Gy for the gross tumor volume (GTV) of the primary tumor and GTV of the positive lymph nodes, 50.7 Gy for the high-risk clinical target volume (CTV), and 45.5 Gy for the low-risk CTV, all delivered in 26 daily fractions. Before SIB-IMRT, L-asparaginase-based induction chemotherapy was used in 95.0% (57/60) of patients. With a median follow-up time of 95.8 months, the 5-year locoregional recurrence-free survival, progression-free survival, and overall survival rates were 83.3%, 81.7%, and 88.3%, respectively. Dosimetric analysis in the first 21 patients showed satisfying conformality for planning target volume of GTV, high-risk CTV, and low-risk CTV, while the organs at risk were well protected. The results of long-term quality-of-life investigations in patients without progression were favorable, and nasal discomfort was the most common symptom. No grade 3 or 4 acute or late toxicities were observed. The scheme of target volume delineation and dose setting that we designed has favorable clinical effects with mild side effects in treating patients with stage I-II nasal cavity NKTCL and Waldeyer's ring NKTCL.

Efficacy and Safety Analysis of Combination Therapy Based on Liposomal Mitoxantrone (Lipo-MIT) in Relapsed/Refractory NK/T-Cell Lymphoma

Background: Currently, there is no standard treatment for relapsed/refractory NK/T-cell lymphoma (NKTCL), which is characterized by highly aggressive and poor prognosis. New drugs are urgently needed to improve the therapeutic effect. Liposomal mitoxantrone (Lipo-MIT) is approved in China for the treatment of relapsed or refractory peripheral T-cell lymphoma patients who have received at least one line standard therapy previously. Phase II study data showed that the objective response rate (ORR) of patients after monotherapy was 41.7% and the complete response rate (CR) was 23.1%. Progression-free survival (PFS) was 8.5 months. Lipo-MIT showed excellent anti-tumor effect in patients with NKTCL subtype, with an ORR of 42.9%, which broke the limitation of natural resistance of NKTCL to anthracyclines. To further improve the efficacy, we tried a combination therapy based on Lipo-MIT in patients with relapsed/refractory NKTCL. Herein we will report its efficacy and safety. Methods: Nine patients with relapsed/refractory NKTCL were enrolled in this study, all of whom had previously received pegaspargase-based combination chemotherapy. The salvage treatment was a combination regimen based on Lipo-MIT. The efficacy was evaluated after every 2 cycles using PET-CT or MRI scan, and hematological and non-hematological adverse events were collected after treatment. Progression-free survival (PFS) was defined as the time from initiation of Lipo-MIT to disease progression, recurrence, death, or last follow-up. Overall survival time (OS) was defined as the time from initiation of Lipo-MIT to death from all causes or the last follow-up. Results: The median age of the nine patients was 53 years old (17-67 years old), and the male-female ratio was 7:2. Eight patients had stage IV NKTCL, one was stage II NKTCL, and all patients had an NRI score of ≥3. The median number of previous treatment lines was 2 (1-4). Three patients had recurrent NKTCL, and six patients had refractory disease to previous treatments, among whom two patients had concurrent hemophagocytic syndrome. The salvage treatment regimens were as follows: Lipo-MIT + pegaspargase + dexamethasone (N=3); Lipo-MIT + pegaspargase + dexamethasone +PD1 monoclonal antibody (N=2); Lipo-MIT +PD1 monoclonal antibody + dexamethasone (N=2); Lipo-MIT + etoposide + pegaspargase + dexamethasone (N=2). Efficacy was evaluable in all patients and the median number of treatment cycles was 3 (2-6). The best response rates were as follows: complete response in 3 (33.3%) patients, partial response in 4 (44.4%) patients, stable disease in 1 (11.1%) patient, and progressive disease in 1 (11.1%) patient. At a median follow-up of 4 months (2-13 months), 6 patients died, including 5 from disease progression and 1 from pegaspargase -associated acute pancreatitis, with a median PFS of 5 months and a median OS of 7 months. One patient underwent allogeneic hematopoietic stem cell transplantation after achieving a complete response and has been disease-free for more than 13 months now. The main adverse reactions of Lipo-MIT combination regimen were grade 3 or more bone marrow suppression (N=7), skin cyanosis (N=4), liver insufficiency (N=4), coagulation dysfunction (N=4), acute pancreatitis (N=1). The median recovery time from myelosuppression was 17 days (6-35 days). There was no correlation between skin cyanosis and efficacy. Conclusion: Combination therapy based on Lipo-MIT has a high remission rate for relapsed/refractory NKTCL, but the duration of remission needs to be further extended, and subsequent allogeneic hematopoietic stem cell transplantation may prolong survival. Lipo-MIT has obvious myelosuppression toxicity, and active supportive therapy should be given when combined with other cytotoxic drugs. In the future, it is worthwhile to conduct prospective clinical trials to explore the optimal combination therapy based on Lipo-MIT in relapsed/refractory NKTCL.

Combination of Mitoxantrone Hydrochloride Liposome with Tislelizumab in Patients with Relapsed or Refractory NK/T Cell Lymphoma: A Phase Ib/Ⅱ Clinical Trial

Background : Extranodal NK/T cell lymphoma (ENKTL) is a highly aggressive malignancy associated with Epstein-Barr virus (EBV) infection, and remains a high unmet clinical need for improving prognosis. Mitoxantrone hydrochloride liposome (PLM60) is a nano-drug that has been approved as the first treatment option for relapsed/refractory (r/r) PTCL, and has shown certain efficacy and safety in a pivotal phase Ⅱ study. Tislelizumab is a humanized immunoglobulin G4 variant monoclonal antibody against PD-1. This trial aims to investigate the safety and efficacy of combining PLM60 with tislelizumab in patients (pts) with r/r ENKTL. Methods: Pts with r/r ENKTL were recruited in this ongoing, prospective, multicenter, open-label phase Ib/Ⅱ study (NCT05464433). Phase Ib was 3+3 design with two dose levels of PLM60 (d1, 16 mg/m 2 and 20 mg/m 2) plus tislelizumab 200 mg (d1, Q4W) induction therapy for up to 6 cycles, then tislelizumab 200 mg (Q3W) to continue maintenance therapy until disease progression, discontinuation, withdrawal or one year of therapy (including induction therapy period). Phase II was a dose expansion at the recommended phase II dose (RP2D). The primary endpoints were to assess the tolerability (i.e. dose-limiting toxicity (DLT)) and explore RP2D of PLM60 in phase Ib, and the objective response rate (ORR) of phase II. Secondary endpoints were complete response (CR) rate, ORR, disease control rate (DCR) and safety of phase Ib, and DCR, progression-free survival (PFS), overall survival (OS) and safety of phase II. Results: At data cut-off on 11 July 2023, 13 eligible pts were enrolled (phase Ib, n=6 and phase II, n=7). 6 pts of phase Ib were evaluable for response with a median age of 29.5 (range, 22-47) years, and 5 pts (83.3%) were ECOG 1. 3 pts (50.0%) had advanced stage III or IV (Ann Arbor). No DLT occurred at 16 mg/m 2 and 20 mg/m 2in phase Ib study. RP2D was PLM60 20 mg/m 2 plus tislelizumab 200 mg. The CR rate, ORR and DCR were 33.3% (2/6, 95% CI 4.3%-77.7%), 100.0% (6/6, 95% CI 54.1%-100.0%) and 100.0% (6/6, 95% CI 54.1%-100.0%), respectively. At data cutoff, the phase II study is being enrolled. Overall, the 11 pts evaluated in phase Ib and phase II had an ORR of 81.8% (9/11) (Figure 1). Furthermore, a decrease in EBV viral load was observed during treatment with PLM60 and tislelizumab except for one pt who experienced viral load rebounded and disease progression after 3 cycles of therapy (Figure 2). With a median follow-up of 2.1 (range, 1.0-5.6) months currently, the median PFS and OS will be reported after long-term follow-up. Treatment-related adverse events (TRAEs) of any grade occurred in all 13 enrolled pts, in which 7 (53.8%) pts were grade 3/4. The common grade 3/4 TRAEs were leucopenia (38.5%), neutropenia (30.8%), lymphocyte count decreased (30.8%), thrombocytopenia (7.7%), alanine aminotransferase increased (7.7%) and diarrhea (7.7%). Three patients had treatment delayed because of AEs. Moreover, no adverse cardiac events occurred during this study. Conclusions: PLM60 plus tislelizumab proves an encouraging efficacy in r/r ENKTL pts with manageable safety profiles.

Efficacy and Safety of Chemotherapy (DDGP vs VIPD) Followed Radiotherapy Vs Radiotherapy Followed Chemotherapy (DDGP vs VIPD) Vs Radiotherapy Alone for Newly Diagnosed Early Stage Extranodal Natural Killer/T Cell Lymphoma: Final Results of a Prospective, Multicenter, Randomized, Controlled Clinical Trial

Background: Extranodal Natural Killer/T Cell Lymphoma (ENKTL) is a highly aggressive form of non-Hodgkin lymphoma (NHL), primarily found in Asia and commonly linked to Epstein-Barr virus (EBV) infection. Despite the treatment efficacy for early stage ENKTL has been improved in recent years, there is no consistent approach for clinical treatment. Current guidelines includes radiotherapy (RT) alone, concurrent chemoradiation therapy (CCRT), sequential chemoradiation, and sandwich chemoradiation. Here we present the final results of the efficacy and safety of sequential therapies of DDGP (dexamethasone, cisplatin, gemcitabine, and pegaspargase) regimen or VIPD (etoposide, ifosfamide, cisplatin and dexamethasone) regimen combined with RT, and RT alone. M ethods: We conducted a prospective, multicenter, randomized, controlled clinical trial to compare the efficacy and safety of sequential chemotherapy (DDGP vs VIPD regimen) followed by RT, sequential RT followed by chemotherapy, and RT alone in eligible patients with newly diagnosed stage I/II ENKTL. Upon study entry, patients were randomized 1:1:1:1:1 to receive either DDGP regimen followed by RT (DDGP+RT), or VIPD regimen followed by RT (VIPD+RT), or RT followed by DDGP regimen (RT+DDGP), or RT followed by VIPD (RT+VIPD), or RT alone. Patients assigned to the DDGP group were administered cisplatin (20 mg/m 2, intravenous, days 1-4), dexamethasone (15 mg/m 2, intravenous, days 1-5), gemcitabine (800 mg/m 2, intravenous, on days 1 and 8), and pegaspargase (2500 IU/m 2, intramuscular, on day 1). Those in the VIPD group received etoposide (100 mg/m 2, intravenous, days 1-3), ifosfamide (1.2 g/m 2, intravenous, days 1-3), cisplatin (33 mg/m 2, intravenous, days 1-3), and dexamethasone (40mg, intravenous, days 1-4). Both the DDGP and VIPD regimens were repeated every 21 days. For the sequential chemotherapy followed by RT group, patients underwent 3 cycles of either DDGP or VIPD regimen, followed by 50 Gy (2 Gy * 25 times) of intensity modulated radiotherapy (IMRT). In the sequential RT followed by chemotherapy group, patients were first given 50 Gy (2 Gy * 25 times) of IMRT and then sequential either DDGP or VIPD regimen. Meanwhile, the RT alone group received 50 Gy (2 Gy * 25 times) of IMRT only. The primary end point of our study was progression free survival (PFS), with secondary end points including complete remission rate (CRR), objective response rate (ORR), overall survival (OS). R esults: Our study, spanning January 2011 to August 2020, involved 244 patients from 22 centers across China, with 200 randomly assigned to receive treatment (40 in each group). Both the demographic and disease characteristics of the patients at baseline were generally consistent across all treatment groups. During a median follow-up of 72.1 months, the median PFS (mPFS) was not reached in neither the DDGP + RT nor RT + DDGP groups, compared to 36.3 months in the VIPD + RT group, 78.3 months in the RT + VIPD group, and 89.6 months in the RT alone group. The 5-year PFS rates for the DDGP + RT, VIPD + RT, RT + DDGP, RT + VIPD, and RT alone groups were 81.5%, 46.1%, 79.8%, 53.1%, and 57.5% respectively. Similarly, the 10-year PFS rates were 81.5%, 42.8%, 74.1%, 45.9%, and 45.7% respectively. Compared with RT alone, PFS was improved in DDGP + RT group (p = 0.006) and RT + DDGP group (p = 0.024). Compared with VIPD + RT, PFS was improved in DDGP + RT group (p = 0.006) and RT + DDGP group (p = 0.026). Either between DDGP +RT and RT + DDGP group or between VIPD +RT and RT +VIPD group, PFS showed no differences. Median OS was not reached in 5 groups. OS showed no differences in 5 groups (p = 0.27). The patients who failed from either VIPD regimen or RT alone received DDGP regimen. This might be the reason why the OS showed no differences between 5 groups. The CRRs of 5 groups (DDGP + RT, VIPD +RT, RT + DDGP, RT +VIPD, RT alone) were 87.5%, 57.5%, 82.5%, 69.2%, and 67.5%, respectively. Similarly, the ORRs were 97.5%, 77.5%, 90.0%, 74.4%, and 87.5%, respectively. Conclusions: The DDGP regimen exhibited promising outcomes in this randomized clinical trial for newly diagnosed early-stage ENKTL patients. The sequential therapies with DDGP regimen could improve the efficacy compared with RT alone. Patients could also benefit more from therapies with DDGP regimen than those with VIPD regimen. The order in which chemotherapy and RT were applied has no fatal impact on the prognosis of early-stage ENKTL.

Predictors of Outcome for Allogeneic Stem Cell Transplantation with a Reduced Intensity Pentostatin/TBI Conditioning Regimen in T-Cell Lymphomas: A Single Center Experience

Background: Allogeneic hematopoietic stem cell transplantation (alloSCT) is a potential curative option for patients with relapsed/refractory T-cell lymphoma (TCL).A reduced intensity conditioning (RIC) regimen of infusional pentostatin and 6 Gy of total body irradiation (TBI) has been shown to be well-tolerated and to have favorable engraftment kinetics 1. We utilized this regimen for patients with aggressive TCL undergoing alloSCT due to the demonstrated activity of pentostatin as a single agent in TCL and its potential impact, along with TBI, on eradicating residual TCL. Methods: This retrospective review includes adult patients with Nodal TCL (PTCL , AITL, ALCL), rare aggressive TCL [(T-ALL, natural killer/T-cell lymphoma (NKTL), adult T-cell leukemia/lymphoma (ATLL), and subcutaneous panniculitis-like T-cell lymphoma (SPTCL)], and T-Prolymphocytic leukemia (TPLL) who underwent alloSCT between 2006 and 2021. The primary objective was to determine transplant related outcomes including grade 3-4 acute graft-versus-host disease (aGVHD), extensive chronic GVHD (cGVHD), relapse, non-relapse mortality (NRM), and overall (OS), relapse-free (RFS), and GVHD-free, relapse-free survival (GRFS) following transplant. A subgroup analysis was conducted to evaluate the impact of disease status at the time of transplant and other factors, including age and subtype of TCL. Results: We report results for 40 patients (Nodal TCL: 21, Rare aggressive TCL: 10, T-PLL: 10) with a median age of 56.6 years ( range 24-71). Seventy-five percent were in clinical CR at the time of transplant. The 1-y cumulative incidence rate (CIN) of aGVHD was 42.5%. The 3-y CIN for cGVHD was 22.9. The median OS was 3.18 years with a 3-y OS rate of 51.9%. The median RFS was 1.24 years, with a 3-year RFS rate of 41.4%. OS and RFS were significantly higher in patients &amp;lt;65 compared to ≥65 (p-value 0.050 and 0.010 respectively), with no difference between the complete response (CR) and non-CR groups or different subtypes of TCL. The median GRFS was 0.52 years, with a 3-year GRFS rate of 20%. There was no statistically significant difference in GRFS or the incidence of GVHD between groups. Renal toxicity was noted in 10 patients. No cases of pulmonary or central nervous system (CNS) toxicities were observed. By day 100, 15 patients had an infection, including 8 bacterial infections and 5 viral infections. A total of 12 patients had reactivation of cytomegalovirus. Twelve patients died within the first year: 4 from relapse, 3 from aGVHD, 3 from infection, 1 from a subdural hematoma after a fall, and 1 from bladder perforation in the setting of hemorrhagic cystitis. Of 13 patients who relapsed, all received salvage therapy and 3 received DLI. Four are alive and in remission. Conclusions: In patients with TCL, RIC for alloSCT was well tolerated and compared favorably with retrospective data from larger groups of patients from CIBMTR and EBMT who were transplanted with different regimens 2. Interestingly, transplant-related outcomes were similar for patients with CR vs partial response (PR) at the time of transplant, and outcomes were better in patients younger than 65. Relapsed patients had a poor outcome despite salvage therapy with only a 30% OS at 3 years. 1. Foss et al, Transfusion 2020 2. Hamadani et al, Blood Advances 2022

Ksd-101 in Patients with EBV-Associated Hematologic Neoplasms: Results from an Ongoing Phase I Clinical Study

Background: The Epstein-Barr Virus (EBV), which has been confirmed by WHO as the first human tumor-associated virus, is a lifelong carrier once infected. EBV-associated Hematologic Neoplasms seriously threats human health, with rapid disease progression, poor prognosis, easy to relapse, and high mortality rate. KSD-101 is a First-in-class autologous dendritic cell (DC) vaccine which is developed to control EBV-associated hematological diseases. Autologous DCs were loaded with the EBV-transformed B-LCL (B-Lymphoblastoid Cell Line) lysates which contains a broad-spectrum EBV antigen to prepare KSD-101 for the treatment of EBV-associated diseases. Methods: In this study, patients (pts) with EBV-associated Hematologic Neoplasms who fail to respond to or relapse after conventional treatment will be recruited and undergo leukapheresis to collect autologous peripheral blood mononuclear cell (PBMC). The enriched monocytes will be induced to differentiate into DCs and prepared as KSD-101 after loading with EBV-transformed B-LCL. Pts will undergo monotherapy with KSD-101, without the need for pre-treatment of lymphodepletion or prophylactic medication. Administration route of KSD-101 is subcutaneous injection, once every 2 weeks for 3-5 vaccinations in total. The study used a 3+3 dose-escalation design. Safety assessment is conducted according to NCI-CTCAE 5.0 grading criteria. The primary objective is to assess the tolerability and safety of KSD-101 in the treatment of EBV-associated Hematologic Neoplasms, explore the dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD). The secondary objective is to explore the clinical efficacy and immune responses of KSD-101 in the patients with EBV-associated Hematologic Neoplasms. Results: As of July 2023, 9pts were enrolled in the study and 8 pts DC vaccine preparations were completed. Three pts were injected 5.0 × 10 6 cells/dose without exploring any DLT. The first two pts in the second dose level were injected 7.5 × 10 6 cells/dose. However, the third pt in second dose level was injected 5.0 × 10 6 cells/dose due to insufficient apheresis collection. Based on the safety and preliminary efficacy data, we decided not to proceed with dose-escalation to the third dose group. In the expansion phase, all pts were injected with a dose of 5.0 × 10 6 cells. Currently observed KSD-101-related toxicities were pyrexia (grade ≤ 2), injection site reactions (grade 1), and lymphadenopathy (grade 1). In all the pts who were injected, neither DLT nor MTD were explored. Based on the comprehensive considerations of safety, efficacy and easibility, we propose that the most appropriate dose is 5.0 × 10 6 cells. Of all pts enrolled, one was excluded due to hemophagocytic lymphohistiocytosis (HLH), among whom 4 pts completed the 12-week follow-up after the first injection for clinical and laboratory assessments. The results showed an overall response rate (ORR):100%, complete response (CR):100%, including 1 case of AITL (EBV infected T, B, NK),1case of CAEBV (EBV infected T, NK),2cases of NK-T cell lymphoma (1 EBV infected B, NK, and the other EBV infected NK). After vaccinations, the total number of lymphocytes of these four pts increased by 1.5 to3.4 times, including 1.6 to 4.2 times of T cells, 2.1 to 6.5 times of activated T cells (CD3 + HLA -DR +), 1.4 to 5.0 times of CD8 + T cells, 1.2 to 3.7 times of CD4 + T cells, 1.7 to 2.0 times of NK cells, and 1.2 to 32.4 times of B cells; meanwhile, the proportion of EBV-specific CTLs increased significantly (ranging from a 2.51% to 4.16% increase), and the proportion of Tregs significantly decreased compared with the baseline (ranging from a 32.49% to 73.81% reduction). Conclusions：Our current study shows that KSD-101 has excellent safety and good preliminary efficacy against EBV-associated Hematologic Neoplasms with efficient induction of immune responses. The results indicate that KSD-101 is a promising therapeutic reagent for the treatment of EBV-associated Hematologic Neoplasms. Larger prospective studies and longer follow-up time is needed to be conducted.

338P Multicenter real-world study of advanced-stage non-nasal type NK/T cell lymphoma (NKTCL): Clinical features, treatment and prognosis

338P Multicenter real-world study of advanced-stage non-nasal type NK/T cell lymphoma (NKTCL): Clinical features, treatment and prognosis

Comparative analysis of clinicopathologic characteristics and prognosis between nasal and nonnasal extranodal NK/T-cell lymphoma.

The clinicopathologic characteristics and prognosis of nasal and nonnasal extranodal natural killer T-cell lymphoma (ENKTL) are considered to be different. However, the underlying features responsible for these differences are not well clarified especially in the era of asparaginase therapy. In total, 1007 newly diagnosed ENKTL patients from 11 medical centers were included in this study. Clinicopathologic characteristics and survival data were collected. The chi-squared test and Kruskal-Wallis test were utilized for the comparison of different groups. Univariable and multivariable Cox proportional hazards models were used to screen prognostic factors. Overall, 869 (86.3%) patients were nasal forms. Compared to patients with nasal ENKTL, nonnasal patients were at more advanced stages and had poor performance status, bone marrow involvement, elevated serum lactate dehydrogenase (LDH), and CD56-negative status (p < 0.05). The 5-year overall survival (OS) for nasal and nonnasal patients were 65.6% and 45.0%, respectively. The OS of nasal forms patients were superior to nonnasal patients, especially in Eastern Cooperative Oncology Group performance status (ECOG PS) (≥2), advanced stage, KPI (HIR/HR), IPI (HIR/HR), PINK (HR), and high EBV DNA load groups. In patients treated with pegaspargase/L-asparaginase-based regimens, the OS of nasal patients was better than that of nonnasal patients. After adjusting the covariates of age, stage, ECOG PS score, LDH, B symptoms, and BM involvement, results showed that the nonnasal site was associated with poor survival of ENKTL. The clinicopathologic characteristics and prognosis of nasal and nonnasal ENKTL patients are different. Nasal forms patients had superior OS than nonnasal patients, especially in the era of asparaginase.

Discovery and biological evaluation of a potent small molecule CRM1 inhibitor for its selective ablation of extranodal NK/T cell lymphoma.

The overactivation of NF-κB signaling is a key hallmark for the pathogenesis of extranodal natural killer/T cell lymphoma (ENKTL), a very aggressive subtype of non-Hodgkin's lymphoma yet with rather limited control strategies. Previously, we found that the dysregulated exportin-1 (also known as CRM1) is mainly responsible for tumor cells to evade apoptosis and promote tumor-associated pathways such as NF-κB signaling. Herein we reported the discovery and biological evaluation of a potent small molecule CRM1 inhibitor, LFS-1107. We validated that CRM1 is a major cellular target of LFS-1107 by biolayer interferometry assay (BLI) and the knockdown of CRM1 conferred tumor cells with resistance to LFS-1107. We found that LFS-1107 can strongly suppresses the growth of ENKTL cells at low-range nanomolar concentration yet with minimal effects on human platelets and healthy peripheral blood mononuclear cells. Treatment of ENKTL cells with LFS-1107 resulted in the nuclear retention of IkBα and consequent strong suppression of NF-κB transcriptional activities, NF-κB target genes downregulation and attenuated tumor cell growth and proliferation. Furthermore, LFS-1107 exhibited potent activities when administered to immunodeficient mice engrafted with human ENKTL cells. Therefore, LFS-1107 holds great promise for the treatment of ENKTL and may warrant translation for use in clinical trials. Yang's laboratory was supported by the National Natural Science Foundation of China (Grant: 81874301), the Fundamental Research Funds for Central University (Grant: DUT22YG122) and the Key Research project of 'be Recruited and be in Command' in Liaoning Province (Personal Target Discovery for Metabolic Diseases).

A case of extranodal NK/T-cell lymphoma, nasal type, diagnosed by scraping cytology of the maxillary gingiva.

Extranodal NK/T-cell lymphoma (ENKTL), nasal type, is often seen in the head and neck region, but there have been rare instances of this disease with initial presentation as a lesion in the oral mucosa. The patient, a woman in her seventh decade of life, presented with an ulcer in the maxillary gingiva, and scraping cytology and biopsy were performed. Cytological specimens showed solitary or small aggregating cells with marked atypia in a necrotic background. Tumor cells were detected that had various nuclear shapes and azure granules in the cytoplasm. Biopsy showed that the tumor cells had diffusely infiltrated or interdigitated into the subepithelium. Immunohistochemistry revealed that the tumor cells had T- and NK cell phenotypes and were Epstein-Barr virus-encoded small RNA (EBER) positive, leading to a diagnosis of ENKTL. Thus, when nonepithelial tumor cells in a necrotic background and prominent atypia are found, as in this case, it is important to carefully observe for azurophil granules in the cytoplasm for differential diagnosis considerations.

Use of PD-1 blockade in refractory/relapsed natural killer T-cell lymphomas: a systematic review and synthesis of case reports

Natural killer/T-cell lymphoma (NK/T-cellL) is an aggressive non-Hodgkin’s lymphoma with limited treatment options for patients who experience disease progression or recurrence after second-line treatment. The use of new therapies, such as pembrolizumab, which involves immune checkpoint blockade mechanisms, is proposed. This systematic review followed the MOSE guidelines and searched PUBMED/MEDLINE, EMBASE, and Scopus databases. Fourteen articles were found, reporting on the use of pembrolizumab anti PD-1 in NK/T-cellL patients. The objective response rate was 84.50%, with disease-free survival ranging from two to 48 months. The complete response rate was 61.6%, and the quality of the reported studies was evaluated to be of high and moderate confidence bias levels in case reports and high bias in clinical trials. Pembrolizumab and others anti PD-1 are treatment options for refractory/recurrent NK/T-cellL, regardless of PD-L1 expression, with good short- and long-term results and low adverse events.

842P Multicenter real-world study of newly diagnosed advanced-stage extranodal natural killer/T cell lymphoma (ENKTL): Proposal for intensive therapy

842P Multicenter real-world study of newly diagnosed advanced-stage extranodal natural killer/T cell lymphoma (ENKTL): Proposal for intensive therapy

Development and Validation of Clinical-Metabolic-Radiomics Model Based on Nomogram-Revised Risk Index for Prognosis Prediction in Patients with Extranodal Natural Kill/T Cell Lymphoma

To identify clinical-metabolic-radiomics model using clinical data and 18F-FDG PET/CT image for predicting progression-free survival (PFS) of nasal-type extranodal natural killer/T cell lymphoma (ENKTCL) on the basis of the nomogram-revised risk index (NRI) model previously established and validated by our research group. A total of 133 ENKTCL patients were prospectively included and randomly divided into a training cohort (n = 73) and a validation cohort (n = 50). 107 features and 7 commonly used metabolic parameters (SUVmax, MTV, TLG, SD, TLR, TAR and TBR) were extracted from baseline PET images of the patients. Least absolute shrinkage and selection operator (LASSO) following Cox regression were used to select optimal features and parameters. NRI-metabolic-radiomics model was developed and validated in the two cohorts and compared with NRI model and NRI-metabolic model. TLG and 5 radiomics features were selected after LASSO and Cox regression. NRI-metabolic (NRI-TLG) model and NRI-metabolic-radiomics (NRI-TLG-RAD) model was developed based on NRI, TLG and selected 5 radiomics features. For PFS, NRI-TLG-RAD showed better PFS discrimination than NRI-TLG model and NRI model in both training cohort (C-index = 0.791, 0.743 and 0.690, respectively) and validation cohort (C-index = 0.785, 0.707, and 0.610 respectively). Moreover, NRI-TLG-RAD model and NRI-TLG model divided more patients into low-risk group (No. of patients: 66, 42 vs. 20) and very high-risk group (No. of patients: 25, 25 vs. 9), compared to preexisting NRI model. The addition of metabolic and radiomics information improved the prognostic performance of preexisting NRI model greatly. Better prognostic discrimination and more reasonable patient division of the new NRI-TLG and NRI-TLG-RAD model may provide the basis for more precise treatment modality in the future.