No abstract

Our data show that patients with MPCM-large lesions compared with those with MPCM-small lesions have a more favorable disease course and suggest exploring the size of cutaneous lesions as a prognostic parameter in childhood-onset MPCM.

Allogeneic hematopoietic stem cell transplantation is associated with serious complications, and improvement of the overall clinical outcome of patients with hematological malignancies is necessary. During the last decades, posttransplant donor-derived adoptive cellular immunotherapeutic strategies have been progressively developed for the treatment of graft-versus-host disease (GvHD), infectious complications, and tumor relapses. To date, the common challenge of all these cell-based approaches is their implementation for clinical application. Establishing an appropriate manufacturing process, to guarantee safe and effective therapeutics with simultaneous consideration of economic requirements is one of the most critical hurdles. In this review, we will discuss the recent scientific findings, clinical experiences, and technological advances for cell processing toward the application of mesenchymal stromal cells as a therapy for treatment of severe GvHD, virus-specific T cells for targeting life-threating infections, and of chimeric antigen receptors-engineered T cells to treat relapsed leukemia.

Basophilia is associated with allergic and parasitic diseases and advanced chronic myeloid leukemia. In the present study, we characterized the expression and function of the death receptors Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors in basophils from healthy donors compared to neoplastic basophils. Peripheral blood basophils obtained from healthy donors (HD-PBB) and from patients with chronic myeloid leukemia (CML-PBB) were found to express high levels of Fas/CD95 and low levels of TRAIL-R2, whereas the basophil-like chronic myeloid leukemia cell line KU-812 expressed significant levels of TRAIL-R1 and TRAIL-R2. HD-PBB underwent apoptosis in response to anti-Fas/CD95, but showed resistance to TRAIL, unless they were co-treated with actinomycin D. Interestingly, CML-PBB and KU-812 cells exhibited the opposite response pattern with resistance to anti-Fas/CD95, but significant susceptibility to TRAIL-induced apoptosis. Our data show that anti-Fas/CD95 and TRAIL differentially regulate apoptosis of normal and neoplastic human basophils, which may direct the development of novel therapeutic strategies.

Background CD19 redirected chimeric antigen receptor (CAR) T-cell therapy has proven efficacy in relapsed or chemotherapy-refractory (r/r) aggressive B-cell non-Hodgkin lymphoma (B-NHL). However, targeting a single B-cell antigen leads to selective pressure with potential antigen-escape and subsequent relapse. A tandem CAR targeting CD20 and CD19 (pLTG1497) has been developed to overcome this limitation. Preclinical evaluation showed improved anti-lymphoma activity. Thus, we initiated a first-in-human, phase I clinical study of autologous pLTG1497-transduced CAR T-cells (MB-CART2019.1) in r/r B-NHL patients. Aims In this phase I prospective multi-center trial (NCT03870945) we aimed to evaluate the maximum tolerated dose (MTD) of MB-CART2019.1 in adult patients with CD20 and CD19 positive r/r B-NHL as determined by dose limiting toxicities (DLTs). Methods This was a 6+3 trial design with two predefined dose levels (DL1 1x106 and DL2 2.5x106 CAR T-cells/kg body weight, respectively). Secondary endpoints included adverse events (AEs) and best overall response rate (ORR). Pharmacodynamic assessments included maximum concentration (Cmax) of CAR T-cells, time to peak expansion (tmax), AUC (d0 to d28), and persistence. MB-CART2019.1 was produced by lentiviral transduction of autologous fresh leukapheresis in the closed automated CliniMACS Prodigy® System (Miltenyi Biotec, Bergisch Gladbach, Germany). Re-infusion (Day 0) of fresh MB-CART2019.1 was scheduled 14 days after leukapheresis. Fludarabine/cyclophosphamide lymphodepleting chemotherapy was administered from day -5 to -3. Results A total of 12 patients, 6 per dose level have been enrolled and treated between February and December 2019, 5 female and 7 male patients. Median age was 72 y (range 20, 78 y), with 10 patients >65 y and 8 >70 y. Histologies included aggressive B-NHL (11) and mantle cell lymphoma (1). Five (5) patients had refractory disease at study entry and IPI was ≥3 in 7 patients. Median time from leukapheresis to re-infusion was 14 d (range 13, 14 d). No DLT and no cytokine release syndrome (CRS) or neurotoxicity grade ≥3 were observed. One patient in dose level 1 experienced a grade 5 AE, which was due to disease progression. CRS grade 1 occurred in 3/6 patients on DL1 and DL2 each, and CRS grade 2 in 2 patients on DL2. Tocilizumab was given in 1 patient. Neurotoxicity grade 1 occurred in 1 patient on DL2. The above described CRS and neurotoxicity resolved completely. Mean Cmax of MB-CART2019.1 was 348.3 cells/µl (range 3.9, 830.4 cells/µl) on DL1 and 692 cells/µl (range 5.3, 3147.8 cells/µl) on DL2. Mean tmax was 15.8 d (range 9, 21 d) on DL1 and 11.5 d (range 9, 14 d) on DL2. Mean AUC was 3155 d*cells/µl (DL1) and 4339 d*cells/µl (DL2). Persistence of MB-CART2019.1 was observed in 12/12 patients until data cut-off. Altogether 9/12 patients (ORR 75%) responded to MB-CART2019.1 with 5/12 CRs. In DL1 3/6 patients responded (ORR 50%) and in DL2 6/6 patients (ORR 100%). The 3 patients without response to MB-CART2019.1 had a mean AUC0-28 of 870 d*cells/µl, whereas mean AUC0-28 in 9 responders was 4843 d*cells/µl reflecting the correlation between the pharmacodynamic parameters and the clinical response. Responses are ongoing in 5/9 patients, with a maximum duration of response of 330 days at data cut-off. Summary/Conclusions In this first-in-human dose finding study of MB-CART2019.1 no DLT and no severe (grade ≥3) CRS or neurotoxicity were observed. Feasibility and safety were very good in this cohort of elderly r/r B-NHL patients. The sustained expansion of tandem CAR T-cells was accompanied by efficacy: all patients (6/6) treated on DL2 responded and all 5 patients with CR (5/5) are in ongoing remission by the time of this report. Based on the promising risk-to-benefit ratio observed in our study, evaluation of MB-CART2019.1 at a dose of 2.5x106/kg body weight in clinical phase II and phase III trials for patients with relapsed aggressive B-NHL is underway. Disclosures Borchmann: Miltenyi Biotec B.V. & Co. KG: Honoraria. Balke-Want:Miltenyi Biotec B.V. & Co. KG: Honoraria. Ayuk:Celgene: Consultancy, Honoraria; Kite/Gilead: Honoraria; Therakos/Mallinckrodt: Honoraria, Research Funding; Neovii: Research Funding; Novartis: Honoraria. Holtkamp:Miltenyi Biomedicine GmbH: Current Employment. Preussner:Miltenyi Biomedicine GmbH: Ended employment in the past 24 months. Zadoyan:Miltenyi Biomedicine GmbH: Current Employment. Hanssens:Miltenyi Biomedicine GmbH: Current Employment. Kaiser:Miltenyi Biotec B.V. & Co. KG: Current Employment. Jurk:Miltenyi Biotec B.V. & Co. KG: Current Employment. Bürger:Miltenyi Biotec B.V. & Co. KG: Current Employment. Schneider:Lentigen Technology Inc., A Miltenyi Company: Current Employment, Patents & Royalties. Dropulic:Lentigen Technology Inc., A Miltenyi Company: Current Employment. Overstijns:Miltenyi Biomedicine GmbH: Current Employment, Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotec B.V. & Co. KG: Current Employment, Membership on an entity's Board of Directors or advisory committees. Scheid:Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria; Takeda: Honoraria, Research Funding. Holtick:Miltenyi Biotec B.V. & Co. KG: Honoraria. Miltenyi:Miltenyi Biomedicine GmbH: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Lentigen Technology Inc., A Miltenyi Company: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Miltenyi Biotec B.V. & Co. KG: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Background: BNT211 comprises two drug products, a chimeric antigen receptor (CAR)-T cell product candidate that targets the tumor specific antigen claudin 6 (CLDN6) and a CAR-T cell-Amplifying RNA Vaccine (CARVac). In mice, CARVac mediates expansion of adoptively transferred CAR-T cells, improving their persistence and functionality. BNT211 aims to establish CAR-T cell therapy for CLDN6-positive solid tumors. Methods: This first-in-human, open label, multi-center trial involves a bifurcated 3+3 design with CLDN6 CAR-T cell dose escalations for both monotherapy (Part 1) and combination with CARVac (Part 2) following lymphodepletion. In Part 2, CARVac is applied q2/3w up to 100 days post CAR-T cell transfer, including a one-step intra-patient dose escalation followed by q6w maintenance dosing. Patients with CLDN6-positive relapsed or refractory solid tumors without further standard treatment options and ECOG 0-1 are eligible for recruitment. Results: As of 19th Jan 2022, 16 patients have been treated, with CAR-T cell transfer performed at dose levels (DLs) 1 and 2 for parts 1 and 2. In total, 37 ≥G3 AEs related to the drug product (mainly cytopenia, or transaminase and lipase elevations without clinical correlates) and 2 DLTs (G4 cytopenia at DL2, part 1 and G4 hemophagocytic lymphohistiocytosis at DL2, part 2) were reported (all resolved). Pronounced cytopenia occurred in patients with testicular cancer who had recently received high-dose chemotherapy and autologous stem cell transplantation. For these patients a lymphodepletion-free/reduced cohort was recently opened. Analysis of CAR-T cell frequency in peripheral blood revealed robust engraftment in all patients, with peak engraftment around day 17. Manageable cytokine release syndrome (G1-2) without any signs of neurotoxicity was observed in 8 patients. Administration of CARVac resulted in transient flu-like symptoms resolving within 24 h. Preliminary efficacy data of 12 evaluable patients 6 weeks after infusion showed 5 patients with PRs (with 39-49% shrinkage of target lesions), 6 with SD and 1 patient with PD (ORR 42%; DCR 92%), with responses seen in testicular and ovarian cancer patients. At 12 weeks, 5 of the 6 patients with PRs showed deepening of responses (50-73% shrinkage). In addition, one testicular cancer patient was treated with a 50% lymphodepletion regime and showed PR after 6 weeks. Conclusions: CLDN6 CAR-T cells ± CARVac show an acceptable safety profile at doses tested and encouraging signs of clinical activity. Data from the completed dose escalation phase will be presented. Acknowledgements: BNT211-01 is funded by BioNTech Cell & Gene Therapies GmbH. Trial registration: Clinicaltrials.gov: NCT04503278. Ethics approval: Ethics & Institutional Review Board approvals were obtained from the respective participating countries prior to initiation of the trial. Citation Format: John BAG Haanen, Andreas Mackensen, Christian Koenecke, Winfried Alsdorf, Eva Wagner-Drouet, Daniel Heudobler, Peter Borchmann, Carsten Bokemeyer, Sebastian Klobuch, Alexander Desuki, Florian Lüke, Erol Wiegert, Catrine Schulz, Benjamin Rengstl, Liane Preussner, Özlem Türeci, Ugur Sahin. BNT211: A Phase I trial to evaluate safety and efficacy of CLDN6 CAR-T cells and CARVac-mediated in vivo expansion in patients with CLDN6-positive advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT002.

BackgroundBNT211 is a chimeric antigen receptor (CAR)-T cell product candidate that targets the tumor specific antigen Claudin-6 (CLDN6). Preclinical studies demonstrated that combining these engineered cells with a CAR-T cell Amplifying RNA Vaccine (CARVac) leads to in vivo expansion of adoptively transferred CAR-T cells, resulting in their improved persistence and functionality.MethodsThis first-in-human, open label, multi-center trial involves a bifurcated 3+3 design with separate CLDN6 CAR-T cell dose escalations (single flat-dose) for monotherapy (part 1) and the combination with CARVac (part 2) based on 3 dose levels (DL). In part 2, CARVac is applied every 3 weeks starting at day 4 post transplantation including a one-step intra-patient dose escalation. Patients with CLDN6-positive relapsed or refractory solid tumors without further standard treatment options and ECOG 0 or 1 are eligible for recruitment.ResultsAs of July 23rd 2021, 8 patients have been treated. DL1 of part 1 has been completed, while dosing of part 1 DL2 and part 2 DL1 is ongoing. One patient with cancer of unknown primary was treated with a dose below DL1 in combination with CARVac; the underlying diseases of the other 7 treated patients were testicular, ovarian and endometrial cancer as well as soft-tissue sarcoma. No acute or dose-limiting toxicities and no serious adverse events related to the drug product have been reported. Manageable cytokine release syndrome (CRS, grade 1-2, the latter managed with Tocilizumab) without any signs of neurotoxicity have been observed in both patients of part 1 DL2. Only transient and moderate elevations of IL-6 and CRP serum levels occurred in remaining patients. Notably, administration of CARVac resulted in transient flu-like symptoms resolving within 24h. Analysis of CAR-T cell frequency in peripheral blood revealed robust engraftment followed by decline after day 17. Further expansion was noted in two patients with liver metastases accompanied by elevated levels of ALT, AST and AP, while total bilirubin was not affected. First tumor assessment 6 weeks after transplantation available for 5/8 patients revealed 4 SD (3 transitioned into PD after an additional 6-18 weeks) and 1 PD. Strikingly, three patients showed initial tumor shrinkage according to RECIST1.1 (reduction of target sum: -18%, -21% and -27%).ConclusionsCLDN6 CAR-T cells +/- CARVac show a favorable safety profile at doses tested and encouraging signs of efficacy. Updated data from open cohorts and especially for combination with CARVac will be presented.AcknowledgementsBNT211-01 is funded by BioNTech Cell & Gene Therapies GmbH.Trial RegistrationClinicaltrialsgov: NCT04503278ReferencesN/A Ethics ApprovalEthics & Institutional Review Board approvals were obtained from the respective participating countries prior to initiation of the trial.ConsentN/A

Mast cells modulate autoimmune diseases such as psoriasis and multiple sclerosis. Fumaric acid esters (FAEs) are widely used for the treatment of psoriasis, and dimethylfumarate (DMF) has recently been approved for multiple sclerosis. In this study, we analysed the cytotoxic effect of FAEs on human mast cells. Specifically, cell death was analysed in the human mast cell line HMC-1 and in primary cord blood-derived mast cells (CBMCs) after incubation with fumaric acid (FA), monomethylfumarate (MMF), DMF and calcium bis(monomethylfumarate) (Ca-MF). Our data show that only DMF potently induces apoptotic cell death in HMC-1 cells and CBMCs. DMF-mediated apoptosis was associated with increased expression of Bax and Bak and activation of caspase-9 and caspase-6. Interestingly, DMF also enhanced the sensitivity of CBMCs towards TRAIL- and dexamethasone-induced apoptosis. These findings demonstrate for the first time that DMF induces apoptosis of human mast cells, primarily via the mitochondrial apoptotic pathway. Our study contributes to the understanding of the beneficial effects of FAEs in autoimmune diseases and provides a rationale for exploiting FAEs for other diseases associated with mast cells.