Sézary Syndrome Patients Research Articles

TCL-458 Real-World Treatment Patterns in Patients With Sézary Syndrome in the United States and the Impact of Covid-19.

Sézary syndrome (SS) is an aggressive type of cutaneous T-cell lymphomas (CTCL). Due to its low prevalence, there are limited data on real-world treatment patterns of available SS therapies. Furthermore, recent approvals of new agents for patients with CTCL as well as COVID-19 likely impacted real-world treatment patterns. To examine real-world treatment patterns and the impact of COVID-19 among SS patients treated in 2018-2020 in the United States. Patients in the 2018-2020 Symphony Health Solutions database were classified into 3 groups: ≥1 diagnosis of SS (ICD-10-CM code: C84.1x) in 2018, 2019, and 2020, respectively. Patient characteristics and treatment patterns for National Comprehensive Cancer Network guideline 2.2021 recommended therapies were examined: systemic therapy (e.g., extracorporeal photopheresis (ECP), parenteral, oral agents), skin-directed therapy (SDT, e.g., topical, local radiation, total skin electron beam therapy, phototherapy) and bone marrow transplant. The impact of COVID-19 was assessed using quarterly analysis. The analyses included 869, 882, and 853 SS patients in 2018, 2019, and 2020, respectively (mean age: 66.3, 66.9 and 67.3 years; male: 54.4%, 54.8%, and 55.6%). Overall, systemic therapy increased from 2018-2020 (41.8% to 46.5%), with increased parenteral (20.7% to 28.7%) but decreased ECP (17.0% to 13.5%) usage. SDT increased from 2018-2020 (48.9% to 52.9%), with increased topical (42.3% to 48.3%) but decreased phototherapy (6.3% to 4.1%) usage. ECP, mogamulizumab, and bexarotene were the most prescribed systemic therapies in 2019-2020, with mogamulizumab being the only one with increased usage over time. Quarterly analysis showed decreasing ECP from Q1 to Q4 within each year, with a notable drop in Q2 2020. For parental systemics, there was an increasing trend in 2019 and 2020, but lower utilization in Q4 2020 than in Q3 2020. For oral systemic, there was a notable drop in Q2 2020 but an increased trend in Q3-Q4 2020. This claims analysis indicated increased use in systemic and SDT among SS patients in 2018-2020. The quarterly analysis indicated that the drop in ECP and oral systemic usage in Q2 2020 coincided with the onset of the pandemic, but there was a stable use of parenteral systemic during 2020.

Concomitant Inhibition of FASN and SREBP Provides a Promising Therapy for CTCL.

Simple SummaryThe biosynthesis of fatty acids catalysed by FASN plays an important oncogenic role in various malignancies but has not been reported in CTCL yet. Here, we show that FASN is highly expressed in both cell lines and primary cells from CTCL patients. The inhibition of FASN impairs cell viability, survival, and proliferation. FASN expression is partly controlled by SREBP, and dual inhibition of FASN and SREBP enhances the impairment of cell proliferation. Overall, our data suggest that the combination of FASN and SREBP inhibitors could be a promising novel strategy in CTCL therapy.Cutaneous T cell lymphoma (CTCL) is a group of non-Hodgkin’s primary cutaneous T cell lymphomas, with Mycosis Fungoides and Sézary syndrome (SS) being the two most common subtypes. Fatty acid synthase (FASN) is a crucial enzyme that catalyses the biosynthesis of fatty acids, which has been reported to play an oncogenic role in various malignancies but not in CTCL so far. Herein, we show that FASN is highly expressed in CTCL cell lines and in peripheral blood mononuclear cells (PBMCs) from CTCL patients, while it is not in PBMCs from healthy individuals. The inhibition of FASN in CTCL cell lines impairs cell viability, survival, and proliferation, but, interestingly, it also increases FASN expression. However, inhibiting sterol regulatory element binding protein (SREBP), a transcription factor that promotes the expression of FASN, partially reversed the upregulation of FASN induced by FASN inhibitors. Thus, the combination of FASN and SREBP inhibitors enhanced the effects on both CTCL cell lines and PBMCs from SS patients, where a valid inhibition on cell proliferation could be verified. Importantly, compared to non-malignant cells, primary malignant cells are more sensitive to the inhibition of FASN and SREBP, making the combination of FASN and SREBP inhibitors a promising novel therapeutic strategy in CTCL.

112 Gene expression changes in sezary syndrome patients following mogamulizumab treatment refines biomarker and immune profile

Sezary syndrome (SS) is the leukemic variant of CD4+ cutaneous T-cell lymphoma. Mogamulizumab is an FDA-approved monoclonal antibody targeting surface CCR4 on SS cells. We’ve previously described highly expressed SS biomarker genes and altered cytokine gene expression that favors a Th2-immune phenotype. Here we evaluated mogamulizumab’s efficacy in reducing malignant T-cells, decreasing SS biomarker gene expression, and modulating cytokine genes to gain insight into cytologic and functional immune changes following treatment.

Combined High-Throughput Approaches Reveal the Signals Driven by Skin and Blood Environments and Define the Tumor Heterogeneity in Sézary Syndrome.

Simple SummarySézary syndrome (SS) is a leukemic and incurable variant of cutaneous T-cell lymphoma characterized by the accumulation of neoplastic CD4+ lymphocytes in the blood, lymph nodes, and skin. With the exception of allogenic transplantation, no curative chance is available to treat SS, and it is a priority to find new therapies that target SS cells within all disease compartments. This review aims to summarize the more recent analyses conducted on skin- and blood-derived SS cells concurrently obtained from the same SS patients. The results highlighted that skin-SS cells were more active/proliferating with respect to matched blood SS cells that instead appeared quiescent. These data shed the light on the possibility to treat blood and skin SS cells with different compounds, respectively. Moreover, this review recaps the more recent findings on the heterogeneity of circulating SS cells that presented a series of novel markers that could improve diagnosis, prognosis and therapy of this lymphoma.Sézary syndrome (SS) is an aggressive variant of cutaneous t-cell lymphoma characterized by the accumulation of neoplastic CD4+ lymphocytes—the SS cells—mainly in blood, lymph nodes, and skin. The tumor spread pattern of SS makes this lymphoma a unique model of disease that allows a concurrent blood and skin sampling for analysis. This review summarizes the recent studies highlighting the transcriptional programs triggered by the crosstalk between SS cells and blood–skin microenvironments. Emerging data proved that skin-derived SS cells show consistently higher activation/proliferation rates, mainly driven by T-cell receptor signaling with respect to matched blood SS cells that instead appear quiescent. Biochemical analyses also demonstrated an hyperactivation of PI3K/AKT/mTOR, a targetable pathway by multiple inhibitors currently in clinical trials, in skin SS cells compared with a paired blood counterpart. These results indicated that active and quiescent SS cells coexist in this lymphoma, and that they could be respectively treated with different therapeutics. Finally, this review underlines the more recent discoveries into the heterogeneity of circulating SS cells, highlighting a series of novel markers that could improve the diagnosis and that represent novel therapeutic targets (GPR15, PTPN13, KLRB1, and ITGB1) as well as new genetic markers (PD-1 and CD39) able to stratify SS patients for disease aggressiveness.

Real-world treatment patterns in patients with Sézary syndrome in the United States and the impact of Covid-19.

e19578 Background: Sézary syndrome (SS) is an aggressive type of cutaneous T-cell lymphomas (CTCL). Due to its low prevalence, there are limited data on real-world treatment patterns of currently available SS therapies. Furthermore, recent approvals of new agents for patients with CTCL as well as COVID-19 likely impacted real-world treatment patterns. Objective: To examine real-world treatment patterns and the impact of COVID-19 among SS patients treated in 2018-2020 in the US. Methods: Patients with public or private insurance in the 2018-2020 Symphony Health Solutions database were classified into 3 groups: ≥1 diagnosis of SS (ICD-10-CM code: C84.1x) in 2018, 2019, and 2020, respectively. Patient characteristics and treatment patterns for all therapies recommended by the National Comprehensive Cancer Network guidelines version 2.2021 were examined: systemic therapy (e.g., extracorporeal photopheresis (ECP), parenteral, or oral agents), skin-directed therapy (SDT, e.g., topical, local radiation, total skin electron beam therapy, or phototherapy) and bone marrow transplant. The impact of COVID-19 was assessed via quarterly analysis. National drug codes, current procedural terminology and healthcare common procedure coding system codes were used to identify all treatments. Results: The analyses included 869, 882, and 853 SS patients in 2018, 2019, and 2020, respectively (mean age: 66.3, 66.9 and 67.3 years; male: 54.4%, 54.8%, and 55.6%). Overall, systemic therapy increased from 2018 to 2020 (41.8% to 46.5%), with increased parenteral (20.7% to 28.7%) but decreased ECP (17.0% to 13.5%) usage. SDT increased from 2018 to 2020 (48.9% to 52.9%), with increased topical (42.3% to 48.3%) but decreased phototherapy (6.3% to 4.1%) usage. ECP, mogamulizumab, and bexarotene were the most prescribed systemic therapies in 2019-2020, with mogamulizumab being the only one with increased usage over time. Quarterly analysis showed a decreasing ECP from Q1 to Q4 within each year, with a notable drop in Q2 2020. For parental systemics, there was an increasing trend in 2019 and 2020, but utilization in Q4 2020 was lower than that of Q3 2020. For oral systemic, there was a notable drop in Q2 2020 but an increased trend in Q3-Q4 2020. Conclusions: This claims analysis indicated increased use in systemic and SDT among SS patients in 2018-2020. The quarterly analysis indicated that the drop in ECP and oral systemic usage in Q2 2020 coincided with the onset of the pandemic, but there was a stable use of parenteral systemic during 2020.

Real-world use of mogamulizumab among patients with mycosis fungoides and Sézary syndrome before and during COVID-19 in the United States.

e19575 Background: Per label, mogamulizumab (Moga) is administered on days 1, 8, 15, and 22 of the first 28-day cycle (loading) and on days 1 and 15 of each subsequent cycle (maintenance) for adult patients with relapsed or refractory mycosis fungoides (MF) or Sézary syndrome (SS) after ≥1 prior systemic therapy. During the COVID-19 pandemic, professional organizations suggested dosing intervals for systemic cancer therapies be extended to limit in-person visits. This study examined the real-world use of Moga before and during the COVID-19 pandemic in the United States. Methods: Using the Symphony Health Solutions database, adults with ≥1 diagnosis (dx) of MF or SS (ICD-10 CM: C84.0x or C84.1x) and ≥1 Moga claim during 10/1/2018-5/6/2021 were identified. Within the MF (no SS dx) and SS (any SS dx) cohorts, patients were divided into 2 subgroups based on their Moga initiation date: 10/1/2018-3/31/2020 (pre COVID-19) and 4/1/2020-5/6/2021 (COVID-19). Patient characteristics and dosing intervals between Moga doses 1-4 (loading) and between subsequent doses (maintenance) were examined. Results: Overall, 154 MF and 204 SS patients initiated Moga during the study period (mean age: 66.8 and 69.2 years; male: 64% and 55%, respectively). In the MF cohort, 98 and 56 patients were in the “pre COVID-19” and “COVID-19” subgroups. The mean dosing interval was shorter among patients in the “COVID-19” subgroup for both the loading (9.1 vs. 13.2 days) and maintenance doses (15.2 vs. 16.1 days) (Table). In the SS cohort, 121 and 83 patients were in the “pre COVID-19” and “COVID-19” subgroups. Mean loading (9.0 vs. 11.1 days) and maintenance (15.0 vs. 16.8 days) dosing intervals were shorter for patients included in the “COVID-19” subgroup. Conclusions: Among MF and SS patients, dosing intervals for Moga in loading and maintenance were not extended during the 1st year of the COVID-19 compared to pre COVID-19. There was a trend towards closer concordance with the label during COVID-19.[Table: see text]

African American and Caucasian patients with Sézary syndrome have no differences in outcomes at an ethnically diverse urban medical center

Sézary syndrome (SS) is an aggressive cutaneous T-cell lymphoma with poor survival. We performed a retrospective review of SS patients at Emory University from 1990 to 2020. We collected data on race, clinical characteristics, therapy, and social determinants of health. Clinical endpoints were overall survival (OS) and time to next treatment (TTNT). Univariate association and multivariable analyses were assessed by Cox proportional hazards models. Among 62 patients, 45.2% were AA. The median OS and TTNT were 3.1 years and 6.3 months, respectively, with no difference by race. AA patients had a higher median baseline LDH (360 vs. 232, p = 0.002) and a longer delay in initiation of systemic therapy compared to CC patients (3.17 vs. 2.14 months, p = 0.039), but a shorter commute (<10 miles) and no difference in insurance coverage (p = 0.260). AA patients at an academic center had unique clinical features and treatment patterns, but similar survival to CC SS patients.

Poor prognostic factors of Sézary syndrome: A retrospective single‐center study from Japan

AbstractObjectivesAlthough the prognosis of Sézary syndrome (SS) is highly unfavorable, the prognostic factors have not been fully understood. In this study, we tried to investigate the prognostic factors in Japanese SS patients for the first time.MethodsWe performed a retrospective cohort study of 19 SS patients who visited our hospital between January 1, 1999, and December 31, 2019. The collected clinical findings were age, gender, performance status (PS), and TNMB staging at diagnosis. TNMB staging was determined according to the International Society for Cutaneous Lymphomas and the cutaneous task force of the European Organization of Research and Treatment of Cancer criteria. The collected hematological findings were serum levels of soluble IL‐2 receptor (sIL‐2R), lactate dehydrogenase (LDH), thymus and activation‐regulated chemokine (TARC), and immunoglobulin E (IgE), Sézary cell count, Sézary cell ratio among white blood cells, and eosinophil count in peripheral blood at diagnosis.ResultsWe analyzed the correlations between overall survival and various clinical and hematological findings. In the log‐rank test, PS1‐3, N2‐3 stage, higher serum levels of LDH (≥355 IU/L), sIL‐2R (≥1729 U/ml) and TARC (≥19,867 pg/ml), and higher Sézary cell count (≥7480/μl) and Sézary cell ratio among white blood cells (≥52%) at diagnosis were associated with decreased overall survival.ConclusionsThis is the first report evaluating prognostic factors in Asian SS patients. This study may contribute to selecting the treatment strategy and improving survival and quality of life of Asian SS patients.

Sézary syndrome patient–derived models allow drug selection for personalized therapy

AbstractCurrent therapeutic approaches for Sézary syndrome (SS) do not achieve a significant improvement in long-term survival of patients, and they are mainly focused on reducing blood tumor burden to improve quality of life. Eradication of SS is hindered by its genetic and molecular heterogeneity. Determining effective and personalized treatments for SS is urgently needed. The present work compiles the current methods for SS patient–derived xenograft (PDX) generation and management to provide new perspectives on treatment for patients with SS. Mononuclear cells were recovered by Ficoll gradient separation from fresh peripheral blood of patients with SS (N = 11). A selected panel of 26 compounds that are inhibitors of the main signaling pathways driving SS pathogenesis, including NF-kB, MAPK, histone deacetylase, mammalian target of rapamycin, or JAK/STAT, was used for in vitro drug sensitivity testing. SS cell viability was evaluated by using the CellTiter-Glo_3D Cell Viability Assay and flow cytometry analysis. We validated one positive hit using SS patient–derived Sézary cells xenotransplanted (PDX) into NOD-SCID-γ mice. In vitro data indicated that primary malignant SS cells all display different sensitivities against specific pathway inhibitors. In vivo validation using SS PDX mostly reproduced the responses to the histone deacetylase inhibitor panobinostat that were observed in vitro. Our investigations revealed the possibility of using high-throughput in vitro testing followed by PDX in vivo validation for selective targeting of SS tumor cells in a patient-specific manner.

CD38 Expression by Circulating and Skin-Infiltrating Lymphocytes from Sezary Syndrome Patients: A Flow Cytometry and Immunohistochemistry Study

Background Reports on the expression of CD38 in Sézary syndrome (SS), erythrodermic primary cutaneous T cell lymphoma with leukemic involvement, are limited. The aim of the present study is the analysis of the expression of CD38 by skin-infiltrating mononuclear cells and circulating T lymphocytes in a cohort of SS patients. Methods SS patients diagnosed since 1985 in our clinic were retrospectively analyzed for CD38 expression in biopsy and blood samples by immunohistochemistry and flow cytometry, respectively. Results SS patients show a predominant CD38-negative phenotype on both skin and blood. A subgroup of patients was found expressing CD38 (12 cases) in either the skin (>25% cell infiltrate) or blood (CD4+CD38+ >50%), among whom 4 in the blood, 7 in the skin, and 1 in both blood and skin. Conclusion The implications of these observations may be twofold: the relevance in basic science is related to a potential role in immune defense regulation, whilst in perspective CD38 may become a target for antibody therapy, considering the availability of different anti-CD38 monoclonal antibodies.

Chimerized Anti-ICOS 314.8 Monoclonal Antibodies Inhibit Tumor Cells and Regulatory T Cells in Patients with Sézary Syndrome

Background: In a previous study, we reported the strong expression of Inducible T-cell costimulatory (ICOS) by Sézary cells, and presented the excellent preclinical efficacy results of anti-ICOS antibody drug conjugates (ADCs) in both Sézary syndrome (SS) and angioimmunoblastic T-cell lymphoma. Although exerting a potent direct action on the tumor cell, ADCs have the disadvantage of being associated with a cumulative toxicity, related to the conjugated drug. The development of antibody-dependent cell-mediated cytotoxicity/phagocytosis (ADCC/ADCP)-inducing anti-ICOS monoclonal antibodies (mAbs) is therefore of great importance to ensure long-term maintenance therapy.Methods: We first determined which anti-ICOS clone was the best candidate to induce an ADCC effect on ICOS + cell lines (MyLa, MJ and HUT78), using Mouse FcγRIII ADCC Bioassay (Promega®). The selected mAb was then chimerized and afucosylated (GlymaxX® technology, Evitria®).Secondly, we evaluated in vitro ADCC and ADCP effect of the chimeric anti-ICOS mAb against ICOS + CTCL cell lines, compared to both positive controls (mogamulizumab (moga) and alemtuzumab) and negative controls (IgG1 isotype control, and rituximab). To perform ADCC experiments, we co-incubated target cells with mAbs and allogenic NK lymphocytes from healthy volunteers (HV). Cellular apoptosis was measured by flow cytometry using the Caspase 3/7 assay (Promega®). For ADCP, monocytes were sorted from HV blood samples and treated with M-CSF. Target cells were labeled with PKH67 (Sigma-Aldrich®) and after co-incubation, CD14 +CD11b +PKH67 + monocytes were analyzed by flow cytometry.Finally, we verified the ADCC/ADCP potency of anti-ICOS mAbs on primary Sézary cells isolated from 16 moga-naïve SS patients, and 6 patients who had developed resistance to moga. We also questioned whether anti-ICOS mAbs were able to promote the autologous apoptosis of Sézary cells and T regulatory cells (Tregs) when directly incubated with peripheral blood mononuclear cells (PBMCs) from patients with SS.Results: Among 7 different anti-ICOS clones, 314.8, 92.17 and 293.1 clones had the higher ADCC activity against MyLa, MJ and HUT78. Of these 3 clones, 314.8 had the best affinity to the receptor, and the best ability to inhibit binding between ICOS receptor and a recombinant ICOS ligand protein. Anti-ICOS 314.8 mAb was then chosen to be chimerized and glyco-engineered.ICOS and CCR4 were strong and similarly expressed on MyLa and MJ. HUT78 had only mild expression of ICOS and CD52. Anti-ICOS mediated potent ADCC of cell lines (respectively 39.1±5% and 52.6±2.4% for MyLa and MJ cells), without significant difference when compared to mogamulizumab. In HUT78 cells, anti-ICOS induced a specific apoptosis of 35.7±5% versus 15.6±5.6% with alemtuzumab (p=0.02; CI95%: 4.1-36.1).Moreover, phagocytosis induced by anti-ICOS was significantly increased than that induced by negative controls. On MyLa cells, anti-ICOS had a greater phagocytosis activity than moga (59.4±5.2% vs 39.4±5.1%, p=0.031).Expression of ICOS by circulating tumor cells was found in all the 16 moga-naïve patients. The expression was strong, as 61±6% of tumor cells expressed ICOS vs 20±8% of non-tumoral CD4 + cells. CCR4 was more expressed than ICOS on both Sézary cells and non-tumoral CD4 + cells (91±6%, and 44±9% respectively). Anti-ICOS induced the apoptosis of 57.1±4.7% Sézary cells, compared to 16.9±2.2% with rituximab (p<0.01; CI95%:-53–27). The efficacy was better than with alemtuzumab, but there was no significant difference with moga. The ADCP effect induced by anti-ICOS did not differ with moga. Interestingly, anti-ICOS were effective in 6 moga-resistant patient, as they induced 38.9±5.9% of apoptosis, compared to 12.4±4.7% with moga (p<0.001).Ex vivo, anti-ICOS allowed 39.4±19.9% and 70.1±20.1% lysis of Sézary cells and Tregs respectively, with no difference with moga and alemtuzumab. However, the depletion of non-tumoral CD4 + and total PBMCs was significantly lower with anti-ICOS mAbs than with moga and alemtuzumab.Discussion: In a recent study, we showed that Treg cells of patients with SS have a high expression of ICOS. Here, we demonstrate that anti-ICOS mAbs induce Tregs depletion, which may improve immune profiles and emphasize Sézary cells killing. Our data suggest robust anti-tumor activity of anti-ICOS mAbs in SS, and xenograft experiments are underway to confirm these findings. DisclosuresLopez: Emergence Therapeutics: Current holder of individual stocks in a privately-held company. Bagot: Takeda: Membership on an entity's Board of Directors or advisory committees. Olive: Alderaan Biotechnology: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; ImCheck Therapeutics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Emergence Therapeutics: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees.

Prec-P-01 - Preclinical investigation of new targeted combination therapies in cutaneous T-cell lymphoma

Prec-P-01 - Preclinical investigation of new targeted combination therapies in cutaneous T-cell lymphoma

Prec-O1-05 - Flow-cytometry and functional evaluation of the CD39/CD73 adenosinergic immunosuppressive axis in patients with Sézary syndrome

Sézary syndrome (SS) is a primary cutaneous T-cell lymphoma characterized by measurable levels of malignant lymphocytes in the blood, and progressive impairment of the immune response. Among the mechanisms of immune modulation, adenosine can impair anti-tumor immunity, through the attenuation of protective effector cells, including T and NK cells, and by enhancing the suppressive capacity of T regulatory cells. CD39 and CD73 nucleotide-metabolizing enzymes are involved in the adenosine-generating pathway: CD39 cleaves ATP and ADP down into AMP, which is converted into adenosine by CD73. The extracellular adenosine deaminase/CD26 complex catalyzes the deamination of adenosine to inosine, thus reducing the adenosine levels. The objective of this study were: to investigate the expression of the of CD39 and CD73 nucleotide-metabolizing ectoenzymes in peripheral blood from SS patients; to define the contribution of the CD39/CD73 adenosinergic immunosuppressive pathway to tumor escape from immune response and immune dysfunctions in patients with SS. CD39 and CD73 expression analyzed in whole blood with multiparametric flow-cytometry from SS patients (n=10) and healthy donors (HD, n=11) revealed altered expression of CD39 and CD73 in SS patients compared to HD. Two subgroups of patients can be identified based on the mutually exclusive overexpression of CD39 or CD73 in CD4+ T cells. Indeed, 7 out of 10 patients had high CD39, while 3 had high CD73. CD4+T cells with high CD39 have low CD73, vice versa those with high CD73 have low CD39. To define whether CD39 and CD73 were biologically active, we compared the ability of peripheral blood CD4+T cells from SS patients and HD to hydrolyze ATP and to convert AMP into adenosine, in vitro. Briefly, CD4+ Tcells from SS/HD were seeded in 48-well plates in HBSS, pretreated or not with specific inhibitors for 1h and then incubated with exogenous (e) eATP (patients with high CD39) or eAMP (patients with high CD73) at 37°C. After 1 h incubation, analyses of the supernatant were performed with an RP-HPLC. Results indicated that CD4+ T cells from SS patients with high levels of CD39 showed an increased ability to hydrolyze ATP with increased generation of AMP compared to normal control cells. In parallel, CD4+ T cells with high levels of CD73 showed increased conversion of AMP into ADO, respect to normal control cells. The aberrant expression of CD39 and CD73 along with loss of CD26 expression in circulating Sézary cells suggest that the sequential activity of CD39 and CD73 ectoenzymes scavenges ATP and generates immunosuppressive adenosine in the tumor microenvironment contributing to tumor immune escape. The results inferred from this study are the starting point for more comprehensive studies towards the development of new therapies targeting the CD39/CD73 adenosinergic axis in order to overcome tumor immunosuppression, allowing the induction of effective anti-tumor immune response.

268 Enhancement of antibody-dependent cellular cytotoxicity is associated with treatment response to extracorporeal photopheresis in Sézary syndrome

Importance: Sézary syndrome (SS) is a rare, leukemic type of cutaneous T-cell lymphoma (CTCL), which can be successfully controlled with extracorporeal photopheresis (ECP). Reliable biomarkers to objectively monitor the response to ECP in patients with SS are missing. Objective: We examined the quantitative and qualitative impact of ECP on natural killer (NK) cell activity in SS patients, and especially their functional ability for antibody-dependent cell-mediated cytotoxicity (ADCC). Further, we address the question if the magnitude of the effect can be associated with the treatment response to ECP in SS patients. Materials and Methods: We collected blood samples before starting therapy and after an average of 9 months of uninterrupted ECP treatment from a case-series of 13 SS patients (8 women, 5 men). This is a single-centre study. All patients were diagnosed according to EORTC-WHO criteria and gave written informed consent to the use of their material and data for research purposes. Blood from healthy volunteers was obtained anonymously from a blood bank. Number of NK cells by flow cytometry, ADCC activity by LDH release assay and flow cytometry, treatment response based on blood tumour staging. Results: NK cell numbers were reduced in SS patients compared to healthy individuals and showed a tendency of recovery after long-term ECP treatment, independent of the response to treatment. Patients with marginal increase (≤1.5 AU-fold) or lack of increase in ADCC activity failed to respond to treatment, while an increase in ADCC efficacy paralleled a positive response to ECP. Conclusions and Relevance: NK-mediated ADCC is selectively enhanced and can serve as a reliable biomarker to objectively monitor response to ECP in patients with SS.

Bio-O2-04 - Enhancement of antibody-dependent cellular cytotoxicity is associated with treatment response to extracorporeal photopheresis in Sézary syndrome

Sézary syndrome (SS) is a rare, leukemic type of cutaneous T-cell lymphoma (CTCL), for which extracorporeal photopheresis (ECP) is a first-line therapy. Reliable biomarkers to objectively monitor the response to ECP in patients with SS are missing. We examined the quantitative and qualitative impact of ECP on natural killer (NK) cell activity in SS patients, and especially their functional ability for antibody-dependent cell-mediated cytotoxicity (ADCC). Further, we addressed the question whether the magnitude of the effect on ADCC can be associated with the anti-cancer efficacy of ECP in SS patients. We assessed numbers of NK cells, ADCC activity, and treatment response based on blood tumor staging in a cohort of 13 SS patients (8 women, 5 men) treated with ECP as a first-line therapy. Blood samples were collected before treatment start and after an average of 9 months of uninterrupted ECP treatment. NK cell numbers were reduced in SS patients compared to healthy individuals and showed a tendency of recovery after long-term ECP treatment, independent of the clinical response to treatment. Patients with marginal increase (≤1.5 AU-fold) or lack of increase in ADCC activity failed to respond clinically to treatment, while patients with an increased ADCC activity showed a reduction in blood tumor burden. NK-mediated ADCC is selectively enhanced and might be a mechanism underlying the effect of ECP while in addition it can possibly serve as a reliable biomarker to objectively monitor response to ECP in patients with SS.

Bio-O2-01 - Mass cytometry and machine learning delineate tumor-defining cells in Sézary syndrome to allow discrimination from benign erythroderma

<h3>Background:</h3> In cancer, the lack of early diagnostic biomarkers is a challenge, results in delayed diagnosis, and can seriously affect treatment and prognosis. Therefore, defining accurate methods for early identification of rare malignant cells is of pivotal importance. We explore the potential of artificial intelligence (AI) to uncover tumor-defining cells in Sézary syndrome (SS), a rare type of skin lymphoma. <h3>Methods:</h3> We established a 37-antibody mass cytometry panel to generate single-cell data from peripheral blood and trained an AI model, called CellCNN, on the datasets. CellCNN is a supervised machine learning algorithm that trains a convolutional neural network with a single layer using labelled single-cell data as inputs. Our study included a discovery cohort of 60 individuals (20 Sézary syndrome patients and as comparators 20 healthy donors and 20 atopic dermatitis patients) and a validation cohort of 33 individuals, containing 11 individuals of each group. Algorithm performance was assessed with area under the curve (AUC), specificity, sensitivity, and F1 score (weighted average of sensitivity and specificity). <h3>Findings:</h3> We discovered a combination of cell surface markers by mass cytometry to sensitively and specifically identify tumor-defining SS cells in blood and validated our results in a blinded setting with zero false positives and only one false negative prediction (AUC of 0.98, sensitivity of 0.91, specificity of 1.0, F1 score of 0.95). To allow easy implementation into routine diagnostics, we further reduced the number of markers to 15 to be used in standard FACS assays. Diagnostic predictions with those FACS settings still achieved very high sensitivity of 1.0 and specificity of 0.91 (AUC of 0.94, F1 score of 0.95). Furthermore, we could show that our model can even classify blood samples from SS patients at an early stage of initial clinical manifestation, which is currently a grand challenge, with a high accuracy (AUC of 0.93, sensitivity of 1.0, specificity of 0.91, F1 score of 0.95). <h3>Interpretation:</h3> This study reports the successful validation and performance of an AI-based algorithm to detect rare tumor-defining cells in lymphoma blood samples. Furthermore, our model allows to accurately distinguish tumor samples at initial clinical suspicion and in advanced disease from its benign mimicker. Our findings pave the way for an easy-to-implement and sensitive diagnostic approach to facilitate early diagnosis of Sézary syndrome, and other tumors with blood involvement as well.

Tre-P-06 - Efficacy of mogamulizumab in mycosis fungoides by patient blood involvement and time to response analysis in mycosis fungoides and Sézary syndrome: a post hoc analysis of the MAVORIC study

Background: Cutaneous T-cell lymphomas (CTCL) are rare forms of non-Hodgkin lymphoma, presenting primarily in the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) account for around two-thirds of all CTCL cases. MAVORIC (NCT01728805) was an open-label, phase 3 study comparing mogamulizumab (Moga) to vorinostat (Vori) in MF and SS patients (pts). Previously published post hoc MAVORIC data has shown trends to higher multicompartmental efficacy with Moga in MF and SS pts with increasing baseline blood tumour burden (Scarisbrick J, et al.

Tre-P-30 - French real-life retrospective study in patients with mycosis fungoides and Sezary syndrome treated by mogamulizumab

<h3>Background:</h3> Mogamulizumab is a defucosylated monoclonal antibody targeting the C-C chemokine receptor 4 (CCR4) and approved for the treatment of adult patients with mycosis fungoides (MF) and Sézary syndrome (SS) who have received at least one prior systemic therapy. The efficacy of mogamulizumab was demonstrated in the open-label, phase 3 MAVORIC clinical trial comparing mogamulizumab to vorinostat. This retrospective observational study was conducted in 14 French centres to further assess efficacy and safety of mogamulizumab in a real-life setting. <h3>Methods:</h3> Data collected from medical records of MF and SS patients treated with mogamulizumab between February 2014 and March 2020 in the participating centres were analysed. Patients treated with mogamulizumab in the MAVORIC trial and still alive at the end of the trial were also included (n=20 pts). The primary endpoint was efficacy based on the percentage of patients achieving complete (CR) or partial (PR) response according to the Global Response Score for MF/SS, at mogamulizumab best response (overall response - ORR). Safety was also evaluated on the number and type of adverse events. <h3>Results:</h3> A total of 124 patients aged 69.3±11.8 (mean ± standard deviation [SD]) years, treated with mogamulizumab were included. Patients (MF: n=55, SS: n=69) had an average disease duration of 4.8±3.4 and 2.8±3.1 (mean ± SD) years, respectively. Prior to mogamulizumab, patients had received a median of 3 systemic treatments lines. The stage of the disease at mogamulizumab initiation was IA – 1.7%; IB – 13.4%; IIA – 6.7%; IIB – 5.9%; IIIA – 6.7%; IIIB 7.6%; IVA1 – 49.6%; IVA2 – 6.7%; IVB – 1.7%. 81 patients had blood involvement at mogamulizumab initiation (B1: n=16; B2: n=65). The average duration of treatment with mogamulizumab was 7.6±11.6 (mean ± SD) months. The ORR was 58.6% [95% CI: 48.8–67.8] in the total population vs 47.1% [95% CI: 32.9–61.5] and 68.3% [95% CI: 55–79.7] in MF and SS subsets, respectively. The response in the blood compartment was 55% [95% CI: 45.2–64.4] in the total population vs 71.7% [95% CI: 58.6–82.5] in SS patients. Side effects related to treatment were recorded in 54% of the patients. Skin adverse reactions were the most common adverse events, with 45 recorded instances occurring in 26 patients; over half (55.6%) of all instances were mild-to-moderate in severity. Infusion-related reactions were recorded in 12.1% of patients and were limited to the first (88%) or second (12%) infusion; only 3 patients had a Grade 3 reaction, but none led to treatment discontinuation. Overall, 7 patients passed away, 5 owing to disease progression (1 stage IIB, 3 stage IVA1, 1 stage IVA2) and 2 to sepsis; neither case of sepsis was considered treatment related. <h3>Conclusion:</h3> This real-life- survey shows both a significant ORR and a favourable safety profile in MF and SS patients treated with mogamulizumab. The shown data are consistent with those observed in MAVORIC study.

A weakly supervised deep learning approach for label-free imaging flow-cytometry-based blood diagnostics

SummaryThe application of machine learning approaches to imaging flow cytometry (IFC) data has the potential to transform the diagnosis of hematological diseases. However, the need for manually labeled single-cell images for machine learning model training has severely limited its clinical application. To address this, we present iCellCnn, a weakly supervised deep learning approach for label-free IFC-based blood diagnostics. We demonstrate the capability of iCellCnn to achieve diagnosis of Sézary syndrome (SS) from patient samples on the basis of bright-field IFC images of T cells obtained after fluorescence-activated cell sorting of human peripheral blood mononuclear cell specimens. With a sample size of four healthy donors and five SS patients, iCellCnn achieved a 100% classification accuracy. As iCellCnn is not restricted to the diagnosis of SS, we expect such weakly supervised approaches to tap the diagnostic potential of IFC by providing automatic data-driven diagnosis of diseases with so-far unknown morphological manifestations.

Qol-P-03 - Quality of life in patients with mycosis fungoides and Sézary syndrome: a review of the literature

Cutaneous T-cell lymphomas (CTCL) are a rare, heterogenous group of T-cell lymphomas that primarily manifest in the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) are considered the classic types of CTCL. The diverse manifestation of CTCL results in a wide range of symptoms with a possible mild to severe impact on quality of life (QoL) depending on the disease stage. Previous studies on QoL in CTCL patients report diverse patient populations and use many different QoL instruments. In the current literature a clear overview on the influence of the different stages of disease (early MF, late-stage MF/SS or total group) on the QoL is lacking. Therefore, a systematic search of the literature was conducted using the PubMed, Embase, PsycINFO, and Web of Science databases. Studies were included if they described QoL in patients with MF and SS retrieved by 14 standardized instruments or qualitative interviews. In total 24 studies were included using 18 different questionnaires to report on dermatology-specific, cancer-specific, and generic QoL. The effect on QoL was found to be greater in patients with late-stage disease as compared to early-stage disease, with significant impairments on functional, emotional, and physical domains. Nonetheless, even in patients with limited disease, QoL was mildly to moderately affected. Overall, pruritus was the most frequent reported and most bothersome symptom. Significant influence of the disease on daily life activities were found, not only in patients but also on caregivers and family. This broad, structured overview on QoL in MF and SS patients underlines the influence of disease stage on QoL, and therefore recommends future studies to distinguish between disease stages when reporting results. Furthermore, this overview can inform clinicians in clinical practice by creating awareness of QoL deficits according to disease stage. Cutaneous T-cell lymphomas (CTCL) are a rare, heterogenous group of T-cell lymphomas that primarily manifest in the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) are considered the classic types of CTCL. The diverse manifestation of CTCL results in a wide range of symptoms with a possible mild to severe impact on quality of life (QoL) depending on the disease stage. Previous studies on QoL in CTCL patients report diverse patient populations and use many different QoL instruments. In the current literature a clear overview on the influence of the different stages of disease (early MF, late-stage MF/SS or total group) on the QoL is lacking. Therefore, a systematic search of the literature was conducted using the PubMed, Embase, PsycINFO, and Web of Science databases. Studies were included if they described QoL in patients with MF and SS retrieved by 14 standardized instruments or qualitative interviews. In total 24 studies were included using 18 different questionnaires to report on dermatology-specific, cancer-specific, and generic QoL. The effect on QoL was found to be greater in patients with late-stage disease as compared to early-stage disease, with significant impairments on functional, emotional, and physical domains. Nonetheless, even in patients with limited disease, QoL was mildly to moderately affected. Overall, pruritus was the most frequent reported and most bothersome symptom. Significant influence of the disease on daily life activities were found, not only in patients but also on caregivers and family. This broad, structured overview on QoL in MF and SS patients underlines the influence of disease stage on QoL, and therefore recommends future studies to distinguish between disease stages when reporting results. Furthermore, this overview can inform clinicians in clinical practice by creating awareness of QoL deficits according to disease stage.