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Melanoma is responsible for 90% of skin cancer-related deaths. Major therapeutic advances have led to a considerable improvement in the prognosis of patients, with the development of targeted therapies (BRAF or MEK inhibitors) and immunotherapy (anti-CTLA-4 or -PD-1 antibodies). However, the tumor constitutes an immunosuppressive microenvironment that prevents the therapeutic efficacy and/or promotes the development of secondary resistances. CD160 is an activating NK-cell receptor initially described as delineating the NK and CD8+T-cell cytotoxic populations. Three forms of CD160 have been described: (1) the GPI isoform, constitutively expressed and involved in the initiation of NK-cells' cytotoxic activity, (2) the transmembrane isoform, neo-synthesized upon cell activation, allowing the amplification of NK cells' cytotoxic functions and (3) the soluble form, generated after cleavage of the GPI isoform, which presents an immuno-suppressive activity. By performing immunohistochemistry analyses, we observed a strong expression of CD160 at the primary cutaneous tumor site of melanoma patients. We further demonstrated that melanoma cells express CD160-GPI isoform and constitutively release the soluble form (sCD160) into the tumor environment. sCD160 was shown to inhibit the cytotoxic activity of NK-cells towards their target cells. In addition, it was found in the serum of melanoma patients and associated with increased tumor dissemination. Altogether these results support a role for sCD160 in the mechanisms leading to the inhibition of anti-tumor response and immune surveillance in melanoma.

Extracranial malignant rhabdoid tumours are tumours that mainly affect young children and have a poor prognosis. In 2014, the European Paediatric Soft-tissue sarcoma Study Group developed treatment recommendations consisting in intensive dose chemotherapy every 2 weeks using vincristine-doxorubicin-cyclophosphamide (VDCy) and ifosfamide-etoposide (IE) associated with early surgery and irradiation of tumour sites.A retrospective study was conducted on children treated in France by these new recommendations up to January 2019.Thirty-five patients were identified. The primary tumour was in miscellaneous soft parts for 18 patients, in the kidney for 11 and in the liver for six. The median age at diagnosis was 17.5 months (range 1.2-198.2). Distant locations (metastatic or synchronous tumours) were present in 37.1% at diagnosis. SMARCB1 germline pathogenic variant was detected in 17.1% of patients. Overall tolerance was good, with 87-97% of theoretical chemotherapy cumulative doses actually delivered. The median interval between two courses was 18 days. Surgical resection was performed in 83% (19 R0, 7 R1 and 3 R2) and local radiotherapy in 49% of patients. After a median follow-up of 50.4 months (range 16.5-134.1), the 2-year overall and event-free survivals were 47.6% (95% confidence interval [CI] 30.2-63.1) and 42.9% (95% [CI] 26.5-58.3), respectively. On univariate analyses, localised disease and gross total resection were significantly associated with favourable outcomes.Intensive dose chemotherapy with VDCy/IE can be administrated with no remarkable short-term toxicity, including in infants. However, the outcome remains poor for patients without gross total resection and with metastatic or multifocal disease. These patients could be stratified into a high-risk group that requires a new immediate therapeutic approach such as targeted agents combined with multimodal therapy.

International audience; Introduction: Very rare pediatric tumors (VRTs), defined by an annual incidence ≤2 per million inhabitants, represent a heterogeneous group of cancers. Due to their extremely low incidence, knowledge on these tumors is scant. Since 2012, the French Very Rare Tumors Committee (FRACTURE) database has recorded clinical data about VRTs in France. This study aims: (a) to describe the tumors registered in the FRACTURE database; and (b) to compare these data with those registered in the French National Registry of Childhood Cancer (RNCE).Methods: Data recorded in the FRACTURE database between January 1, 2012 and December 31, 2018 were analyzed. In addition, these data were compared with those of the RNCE database between 2012 and 2015 to evaluate the completeness of the documentation and understand any discrepancies.Results: A total of 477 patients with VRTs were registered in the FRACTURE database, representing 97 histological types. Of the 14 most common tumors registered in the RNCE (772 patients), only 19% were also registered in the FRACTURE database. Total 39% of children and adolescent VRTs registered in the RNCE and/or FRACTURE database (323 of a total of 828 patients) were not treated in or linked to a specialized pediatric oncology unit.Conclusion: VRTs represent many different heterogenous entities, which nevertheless account for 10% of all pediatric cancers diagnosed each year. Sustainability in the collection of these rare tumor cases is therefore important, and a regular systematic collaboration between the FRACTURE database and the RNCE register helps to provide a more exhaustive picture of these VRTs and allow research completeness for some peculiar groups of patients.

TIGIT is an immune checkpoint inhibitor expressed by effector CD4 þ and CD8 þ T cells, NK cells, and regulatory T cells (Tregs). Inhibition of TIGIT-ligand binding using antagonistic anti-TIGIT mAbs has shown in vitro potential to restore T-cell function and therapeutic efficacy in murine tumor models when combined with an anti–PD(L)-1 antibody. In the current work, we demonstrate broader TIGIT expression than previously reported in healthy donors and patients with cancer with expression on gd T cells, particularly in CMV-seropositive donors, and on tumor cells from hematologic malignancies. Quantification of TIGIT density revealed tumor-infiltrating Tregs as the population expressing the highest receptor density. Consequently, the therapeutic potential of anti-TIGIT mAbs might be wider than the previously described anti–PD(L)-1-like restoration of ab T-cell function. CD155 also mediated inhibition of gd T cells, an immune population not previously described to be sensitive to TIGIT inhibition, which could be fully prevented via use of an antagonistic anti-TIGIT mAb (EOS-448). In PBMCs from patients with cancer, as well as in tumor-infiltrating lymphocytes from mice, the higher TIGIT expression in Tregs correlated with strong antibody-dependent killing and preferential depletion of this highly immunosuppressive population. Accordingly, the ADCC/ADCP–enabling format of the anti-TIGIT mAb had superior antitumor activity, which was dependent upon Fcg receptor engagement. In addition, the anti-TIGIT mAb was able to induce direct killing of TIGIT-expressing tumor cells both in human patient material and in animal models, providing strong rationale for therapeutic intervention in hematologic malignancies. These findings reveal multiple therapeutic opportunities for anti-TIGIT mAbs in cancer therapeutics.

International audience; Sézary syndrome is an aggressive form of cutaneous T-cell lymphoma characterized by the presence of a malignant CD4+ T-cell clone in both blood and skin. Its pathophysiology is still poorly understood, and the development of targeted therapies is hampered by the absence of specific target proteins. AAC-11 plays important roles in cancer cell progression and survival and thus has been considered as an anticancer therapeutic target. In this study, we show that a peptide called RT39, comprising a portion of AAC-11‒binding site to its protein partners coupled to the penetratin sequence, induces the specific elimination of the malignant T-cell clone both ex vivo on the circulating cells of patients with Sézary syndrome and in vivo in a subcutaneous xenograft mouse model. RT39 acts by direct binding to PAK1 that is overexpressed, located in the plasma membrane, and constitutively activated in Sézary cells, resulting in their selective depletion by membranolysis. Along with the absence of toxicity, our preclinical efficacy evidence suggests that RT39 might represent a promising alternative therapeutic tool for Sézary syndrome because it spares the nonmalignant immune cells and, contrary to antibody-based immunotherapies, does not require the mobilization of the cellular immunity that shows heavy deficiencies at advanced stages of the disease.

T-cell lymphomas are a heterogeneous group of malignancies involving T lymphocytes and generally characterized by a poor prognosis. Among them, cutaneous T-cell lymphomas (CTCL) involve primarily the skin. The most frequent CTCL are mycosis fungoides and Sézary syndrome (SS) (1). There is no cure for advanced-stage CTCL, the remissions are generally rare and short, and the overall survival is around 5 years with an impaired quality of life. Thus, the development of new treatments inducing longstanding responses in CTCL is a major unmet need (2). Because Sézary cells express several Treg markers as PD-1, ICOS, CD39 or CCR8 (3), we analyzed the expression of CD51, the αV integrin, which is expressed with the β8 integrin on Treg cells (4). CD51 is involved in the production of active form of TGF-β, a cytokine with immunosuppressive properties that promotes tumor escape. Thus, targeting the αVβ8 integrin with a specific antibody has been shown to inhibit TGF-β activation while not inhibiting cell adhesion (5). Our results revealed that CD51 is significantly overexpressed in circulating lymphocytes from SS patients as compared to healthy individuals. Interestingly, CD51 is not associated with the β8 integrin but with CD29 (β1 integrin), and CD61 (β3 integrin) in some patients.CD51/CD29 and/or CD51/CD61 heterodimers appear as potential therapeutic targets in T-cell lymphoma, which may be associated with the production of active TGF-β. Targeting these heterodimers with specific antibodies to prevent the release of active TGF-β could improve patient’s antitumor immune response. They could also represent depleting targets through NK or CAR-T cells activities as shown in diffuse intrinsic pontine glioma and glioblastoma for CD51/CD61 heterodimer (6). 1. Dobos G, et al. Epidemiology of Cutaneous T-Cell Lymphomas: A Systematic Review and Meta-Analysis of 16,953 Patients. Cancers. 11 oct 2020;12(10).2. Scarisbrick JJ, et al. The changing therapeutic landscape, burden of disease, and unmet needs in patients with cutaneous T-cell lymphoma. Br J Haematol. févr 2021;192(4).3. Giustiniani J, et al. CCR8 is a new therapeutic target in cutaneous T-cell lymphomas. Blood Adv. 2022 Feb 24.4. Stockis J, et al. Blocking immunosuppression by human Tregs in vivo with antibodies targeting integrin αVβ8. Proc Natl Acad Sci U S A 2017 Nov 21;114(47).5. Tsui P, et al. The TGF-β inhibitory activity of antibody 37E1B5 depends on its H-CDR2 glycan. mAbs. janv 2017;9(1):104-13.6. Cobb D, de Rossi J, Liu L, An E, Lee D. Targeting of the alphav beta3 integrin complex by CAR-T cells leads to rapid regression of diffuse intrinsic pontine glioma and glioblastoma J Immunother Cancer 2022. Citation Format: Jérôme Giustiniani, Anne Marie-Cardine, Sadjia Belkhelouat, Martine Bagot, Armand Bensussan, Nicolas Ortonne, Adèle De Masson. Targeting the CD51/TGF-beta pathway: a potential innovative cancer immunotherapy in T-cell lymphomas. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3644.

Background: Due to their basal stress phenotype associated to transformation, cancer cells are addicted to non-mutated, non-oncogenic proteins that do not bear such vital functions in normal cells, a phenomenon referred as Non-Oncogenic Addiction (NOA). Targeting these NOAs could therefore induce selective killing of cancer cells, opening several therapeutic opportunities. Recent data suggest that the stress-related scaffold protein AAC-11 (anti-apoptosis clone 11, also known as Api5) is critically involved in cancer cells resistance to chemotherapies, metastatic potential and escape from the immune system. Methods: We have developed inactivating peptides based on the fusion of a cell penetrating sequence and portions of the leucine-zipper domain of AAC-11, which functions as a protein-protein interaction module. These peptides induce cancer cells death, through the inhibition of protein-protein interactions between AAC-11 and its partners, while sparing normal cells. We now describe further characterization of our lead peptide, JRT39, which contains residues 377 to 379 of AAC-11 linked to the cell-penetrating peptide “penetratin”. Results: In vitro, JRT39 causes cell death in a wide spectrum of cancer cell lines with IC50 ranging from 5 µM to 30 µM depending on tumor cell type. In particular, JRT39 showed selective efficacy towards primary cells from Acute Myeloid Leukemia (AML), Acute Lymphocytic Leukemia (ALL) or Sézary syndrome (SS) patients, while sparing normal hematopoietic cells, with an IC50 of 5-15 µM. Mechanistically, JRT39 induces membranolysis of cancer cells through binding to p21-activated kinase 1 (PAK1) in AML or SS cells plasma membrane, where PAK1 is overexpressed. In addition, JRT39 exerted potent anti-tumor activity in vivo in disseminated or subcutaneous AML, APL (Acute Promyelocytic Leukemia) and SS-patient derived preclinical murine models. Preliminary pharmacokinetic studies revealed that JRT39 is stable in human serum and has a plasma half-life of ~1.5-2.5 hours after intravenous (IV) administration to dogs or cynomolgus monkeys, with concentration-time data fitting 2-compartment model. Finally, JRT39 was well tolerated at 5 and 10 mg/kg after single or repeated (daily) IV injections. Conclusions: Combined, our preclinical data confirm that interfering with AAC-11-related survival pathways is a promising novel anticancer strategy and support the development of JRT39 for the treatment of cancer. Citation Format: Louise Jeammet, Emile Adicéam, Justine Habault, Anna Kaci, Jeannig Berrou, Mélanie Dupont, Nicolas Thonnart, Ewa Pasquereau-Kotula, Anne Marie-Cardine, Armand Bensussan, Marika Pla, Hervé Dombret, Claude Gardin, Martine Bagot, Jean-Christophe Rain, Hélène Sicard, Jérôme Tiollier, Thorsten Braun, Jean-Luc Poyet. AAC-11 survival pathways as therapeutic target in cancer: AAC-11 leucine-zipper domain derived peptides exert potent antitumor effects and exhibit favorable stability, pharmacokinetic and toxicology profiles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 464.

Within the tumor microenvironment (TME), TREGS have been associated with worse prognosis and/or resistance to checkpoint inhibitor (CPI) therapy in various cancer diseases, making these cells a promising target for the development of new immunotherapies. Here, we present recent preclinical development data about ALD2510, a next-gen low-fucose IL-2/TCONV-sparing anti-CD25 antibody designed for the selective depletion of CD25high TREGS and the boost of host anti-tumor immunity. Ultra-humanization of parental anti-CD25 antibody was achieved through phage display and, in parallel, all putative liability sequences were replaced for maximizing developability while minimizing off-target and immunogenicity risks. ALD2510 sequences were re-formatted and used for further CHO cell line development, using the GlymaxX™ technology which boosts Fc effector functions. Early tox ALD2510 material was produced following 10L fed-batch USP/DSP and analytical characterization, including a 6-month early stability study. Preliminary safety and pharmacokinetic/pharmacodynamic (PKPD) profile of ALD2510 were then determined through a non-GLP MTD/DRF study in cynomolgus monkey. ALD2510 demonstrated excellent potency (TREG depletion, ADCC, ADCP), manufacturability and stability together with very low immunogenicity potential. CHO productivity reached ~4g/L in 10L fed-batch bioreactor and characterization revealed excellent purity and activity in line with its low fucose content, together with very low levels of process- or cell-related impurities. This material showed a good behavior during the 6-month stability study and was therefore administered in cynomolgus monkeys during a non-GLP exploratory MTD/DRF study. Increasing doses of ALD2510 (from 0.3 to 100mg/kg) were given to four animals during MTD and same animals received three additional doses at 100mg/kg during DRF. Very good tolerability and safety were reported in animals. ALD2510 half-life and exposure were found consistent with that of humanized IgG1 in cynomolgus. Strong TREG depletion was monitored in the blood in all animals with, importantly, no drop was observed in CD4+ or CD8+ T-cells, confirming ALD2510 capacity to selectively target TREGS while sparing TCONV. Overall, ALD2510 demonstrated excellent potency, manufacturability and stability during the 1st phase of preclinical development. Very good tolerability and safety profile together with satisfying PKPD data were reported during exploratory MTD/DRF study in cynomolgus monkeys. Noteworthy, strong TREG depletion was confirmed while CD4+ or CD8+ T-cells were not impacted, confirming ALD2510 selectivity for TREGS while sparing TCONV. This makes ALD2510 a promising candidate for the treatment of solid tumors, in particular those where the presence of TREGS in the TME is associated with worse prognosis and/or resistance to CPI. Citation Format: Jemila Houacine, Riad Abes, Anne Marie-Cardine, Aude Le Roy, Bettina Serbin, Lucie Robert, Jérôme Giustiniani, Anne-Sophie Chrétien, Stéphane Fattori, Laurent Gorvel, Armand Bensussan, Daniel Olive, Arnaud Foussat. Preclinical development of ALD2510, a Next-Gen Fc-enhanced, TREG-selective and IL-2-sparing anti-CD25 antibody for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 710.

International audience; Among 143 patients with elastase, neutrophil-expressed (ELANE)-related neutropenia enrolled in the French Severe Chronic Neutropenia Registry, 94 were classified as having severe chronic neutropenia (SCN) and 49 with cyclic neutropenia (CyN). Their infectious episodes were classified as severe, mild or oral, and analysed according to their natural occurrence without granulocyte-colony stimulating factor (G-CSF), on G-CSF, after myelodysplasia/acute leukaemia or after haematopoietic stem-cell transplantation. During the disease’s natural history period (without G-CSF; 1913 person-years), 302, 957 and 754 severe, mild and oral infectious events, respectively, occurred. Among severe infections, cellulitis (48%) and pneumonia (38%) were the most common. Only 38% of episodes were microbiologically documented. The most frequent pathogens were Staphylococcus aureus (37·4%), Escherichia coli (20%) and Pseudomonas aeruginosa (16%), while fungal infections accounted for 1%. Profound neutropenia (3000/mm(3) ) and neutropenia subtype were associated with high risk of infection. Only the p.Gly214Arg variant (5% of the patients) was associated with infections but not the overall genotype. The first year of life was associated with the highest infection risk throughout life. G-CSF therapy achieved lower ratios of serious or oral infectious event numbers per period but was less protective for patients requiring >10 µg/kg/day. Infections had permanent consequences in 33% of patients, most frequently edentulism.

International audience; We previously reported results of a French randomized clinical trial (RCT) comparing the risk of transplantation failure (including transplant-related mortality [TRM], engraftment failure, and autologous recovery) in single and double unrelated cord blood (UCB) transplantation in children and young adults with hematologic malignancies. We concluded that single-UCB transplantation with an adequate cell dose is the standard of care, leading to a 70% two-year overall survival (OS). It remains unclear, however, whether RCT participants have better outcomes than comparable patients not treated in the setting of a clinical trial. We compared the characteristics and outcomes of RCT participants (n = 137) to a Francophone population-based registry of patients (real-world [RW] group) fulfilling the eligibility criteria used in our RCT and transplanted with 1 or 2 UCB units after a myeloablative conditioning (MAC) regimen between March 2015 (end of inclusion in the RCT) and February 2019 (n = 141). The primary endpoint was the 2-year cumulative incidence (CI) of transplantation strategy failure as defined in our RCT. The 2 groups were comparable in terms of age, disease distribution, hematologic status at transplantation, follow-up, and HLA compatibility. Patients in the RW group were more likely to be transplanted with a single-unit UCB (87.9% versus 49.6%, P< .001) and to receive a radiation-free regimen (39.0% versus 60.6%, P< .001). The 2-year CI of transplantation strategy failure, TRM, and the 2-year probability of OS were similar between the 2 groups, although the relapse risk was higher in the RW group (31.2% ± 7.7% versus 20.4% ± 6.8%, P= .01), resulting in a significantly lower disease-free survival (DFS) (59.2% ± 8.4% versus 69.3% ± 8.0%, P= .047). This difference remained statistically significant only in the group of patients with acute lymphoid leukemia (ALL) who did not receive the conditioning regimen recommended by the RCT (fludarabine 75 mg/m2, total body irradiation 12 Gy, cyclophosphamide 120 mg/kg). The results of our RCT appear to be reproducible in real-world conditions, provided that the same cord blood selection criteria and conditioning regimen are used.

In this study, we have identified a novel cell-penetrating sequence, termed hAP10, from the C-terminus of the human protein Acinus. hAP10 was able to efficiently enter various normal and cancerous cells, likely through an endocytosis pathway, and to deliver an EGFP cargo to the cell interior. Cell penetration of a peptide, hAP10DR, derived from hAP10 by mutation of an aspartic acid residue to an arginine was dramatically increased. Interestingly, a peptide containing a portion of the heptad leucine repeat region domain of the survival protein AAC-11 (residues 377-399) fused to either hAP10 or hAP10DR was able to induce tumor cells, but not normal cells, death both ex vivo on S&eacute, zary patients&rsquo, circulating cells and to inhibit tumor growth in vivo in a sub-cutaneous xenograft mouse model for the S&eacute, zary syndrome. Combined, our results indicate that hAP10 and hAP10DR may represent promising vehicles for the in vitro or in vivo delivery of bioactive cargos, with potential use in clinical settings.

Cutaneous T-cell lymphomas (CTCLs) are rare malignancies involving primarily the skin. Responses to treatment are usually short-lived in advanced CTCL. The determinants of long-term CTCL control are unclear. Mogamulizumab, an anti-human CCR4 antibody that acts by antibody-dependent cell cytotoxicity against CCR4+ CTCL tumor cells and peripheral memory blood regulatory T cells, has been associated with long-lasting remissions and immune adverse events. Here, we reported skin rashes in 32% of 44 patients with CTCL treated with mogamulizumab, associated with significantly higher overall survival (hazard ratio, 0.16; 0.04-0.73; P = .01). Rash occurred in patients with Sézary syndrome and was associated with longer time to progression. These rashes were characterized by a CD163+ granulomatous and/or CD8+ lichenoid skin infiltrate. High-throughput sequencing analysis of T-cell receptor β genes in skin and blood flow cytometry confirmed the depletion of CTCL tumor cells, as well as the recruitment of new reactive T-cell clones in skin at the time of skin rash. CXCL9 and CXCL11, two macrophage-derived chemokines that recruit CXCR3+ T cells to skin, were overexpressed in skin rashes. A higher frequency of TIGIT+ and PD1+ exhausted reactive blood T cells was observed at baseline in patients with rash, and this frequency decreased with mogamulizumab treatment. These data are consistent with mogamulizumab-induced long-term immune CTCL control by activation of the macrophage and T-cell responses in patients with rash.

Noninfectious manifestations-allergy, autoimmunity/inflammation, lymphoproliferation, and malignancies-are known to exist in many primary immunodeficiency diseases (PID) and to participate in prognosis.To obtain a global view on their occurrence, we retrieved data from a retrospective cohort of 1375 patients included in the French National Reference Center for Primary Immune Deficiencies (CEREDIH) for whom we had a 10-year follow-up since inclusion in the registry.These patients were followed for 10 years (2009-2018) by specialized centers in university hospitals. This study showed that 20.1% of patients without prior curative therapy (n = 1163) developed at least 1 manifestation (event) encompassing 277 events.Autoimmune/inflammatory events (n = 138) and malignancies (n = 85) affected all age classes and virtually all PID diagnostic groups. They were associated with a risk of death that occurred in 195 patients (14.2%) and were found to be causal in 43% of cases. Malignancies (odds ratio, 5.62; 95% confidence interval, 3.66-8.62) and autoimmunity (odds ratio, 1.9; 95% confidence interval, 1.27-2.84) were clearly identified as risk factors for lethality. Patients who underwent curative therapy (mostly allogeneic hematopoietic stem cell transplantation, with a few cases of gene therapy or thymus transplantation) before the 10-year study period (n = 212) had comparatively reduced but still detectable clinical manifestations (n = 16) leading to death in 9.4% of them.This study points to the frequency and severity of noninfectious manifestations in various PID groups across all age groups. These results warrant further prospective analysis to better assess their consequences and to adapt therapy, notably indication of curative therapy.