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Objective: Allogeneic stem cell transplantation (allo‐SCT) may have a curative potential due to the graft versus lymphoma effect. In this study, we aimed to compare transplant outcomes between refractory‐T‐NHL (ref‐NHL) and Chemosensitive‐T‐NHL (CS‐T‐NHL). Materials and Methods: We retrospectively reviewed the records of 26 ref‐NHL and 29 CS‐T‐NHL consecutive patients who underwent allo‐SCT at our center and compared the transplant outcomes between the groups. Results: All patients were heavily pretreated with 27% of patients relapsing post‐auto‐SCT and two patients in the ref‐T‐NHL post‐allo‐SCT. Patients were transplanted mainly from unrelated donors. There were no differences in leucocytes and platelet engraftment between the two groups. At 3 years, the relapse incidence was 34% in Ref‐TNHL and 19% in CS‐TNHL (p =.33), with non‐relapse mortality rates of 28% and 22%, respectively (p =.52). Female patients and those with a previous auto‐SCT had lower relapse incidence (p =.045, p =.003). The 3‐year overall survival was 39% in Ref‐TNHL and 56% in CS‐TNHL (p =.15). Trends for improved progression‐free survival (PFS) and graft‐versus‐host disease relapse‐free survival (GRFS) were observed in the CS‐TNHL group (PFS: 60% vs. 30%, p =.075; GRFS: 38% vs. 21%, p =.1). Conclusion: Acknowledging the retrospective nature of our study, our results indicate that allo‐SCT has a curative potential in patients with T‐NHL even in refractory status. [ABSTRACT FROM AUTHOR]

Simple Summary: Chimeric antigen receptors (CARs) are used to recognize highly specific antigens ("mugshots") to target immune effectors ("policemen") against cancer cells. Whereas this new immunotherapy has already set novel standards in the treatment of some specific types of blood cancer, it has not yet been successful with most blood (and solid) cancers for different reasons. In this work, the authors investigated the possibility of using a specific antigen called CD45 as target for CAR therapies. CD45 stands out by being present on all blood cells and therefore represents a promising target in any type of blood cancer. However, immune cells themselves also harbor CD45 at their cell surface, which is expected to lead to either inactivity of the CAR or self-killing of immune cells. To avoid these problems the Hamburg group used a trick—they applied the CRISPR/Cas gene scissors and thus produced CD45-knockout (CD45ko) immune-effector cells. Even though CD45 had been supposed to be important for the functionality of immune-effector cells, the authors observed excellent survival, proliferation and killing activities of their CD45ko CAR cells, independent of the targeted cancer-cell population. Their results thus provide initial proof-of-concept for the potential usefulness of CD45ko/CD45-CAR immune cells to target blood cancer. Background: CAR-T cell therapy has shown impressive results and is now part of standard-of-care treatment of B-lineage malignancies, whereas the treatment of myeloid diseases has been limited by the lack of suitable targets. CD45 is expressed on almost all types of blood cells including myeloid leukemia cells, but not on non-hematopoietic tissue, making it a potential target for CAR-directed therapy. Because of its high expression on T and NK cells, fratricide is expected to hinder CD45CAR-mediated therapy. Due to its important roles in effector cell activation, signal transduction and cytotoxicity, CD45 knockout aimed at preventing fratricide in T and NK cells has been expected to lead to considerable functional impairment. Methods: CD45 knockout was established on T and NK cell lines using CRISPR/Cas9-RNPs and electroporation, and the successful protocol was transferred to primary T cells. A combined protocol was developed enabling CD45 knockout and retroviral transduction with a third-generation CAR targeting CD45 or CD19. The functionality of CD45ko effector cells, CD45ko/CD45CAR-T and CD45ko/CD19CAR-T cells was studied using proliferation as well as short- and long-term cytotoxicity assays. Results: As expected, the introduction of a CD45-CAR into T cells resulted in potent fratricide that can be avoided by CD45 knockout. Unexpectedly, the latter had no negative impact on T- and NK-cell proliferation in vitro. Moreover, CD45ko/CD45CAR-T cells showed potent cytotoxicity against CD45-expressing AML and lymphoma cell lines in short-term and long-term co-culture assays. A pronounced cytotoxicity of CD45ko/CD45CAR-T cells was maintained even after four weeks of culture. In a further setup, we confirmed the conserved functionality of CD45ko cells using a CD19-CAR. Again, the proliferation and cytotoxicity of CD45ko/CD19CAR-T cells showed no differences from those of their CD45-positive counterparts in vitro. Conclusions: We report the efficient production of highly and durably active CD45ko/CAR-T cells. CD45 knockout did not impair the functionality of CAR-T cells in vitro, irrespective of the target antigen. If their activity can be confirmed in vivo, CD45ko/CD45CAR-T cells might, for example, be useful as part of conditioning regimens prior to stem cell transplantation. [ABSTRACT FROM AUTHOR]

Introduction: Chimeric antigen receptor (CAR) T cells targeting B cell maturation antigen (BCMA) have shown impressive results in clinical studies for relapsed/refractory multiple myeloma (RRMM). We performed a systematic literature review to summarize the current body of evidence on the role of anti‐BCMA CAR T cells for RRMM. Objectives and Methods: Fifteen studies comprising a total of 285 patients with heavily pretreated RRMM were included using a conventional meta‐analysis. Main efficacy outcomes were response, relapse, and survival. Safety outcomes were cytokine release syndrome (CRS) and neurotoxicity. Results: Anti‐BCMA CAR T cells resulted in a pooled overall response of 82% (95% confidence interval [CI], 74%‐88%) and complete response of 36% (24%‐50%). Higher CAR+ cell doses were associated with higher response rates. The pooled relapse rate of responders was 45% (27%‐64%), and median progression‐free survival was 10 months. Present extramedullary disease did not show worse outcome. Severe CRS grades 3‐4 and neurotoxicity occurred in 15% (10%‐23%) and 18% (10%‐31%). Conclusion: Anti‐BCMA CAR T cells showed high response rates, even in patients with present extramedullary disease, while relapse occurred in half of the patients who achieved a response. Larger studies with longer follow‐up especially evaluating the association of response and survival are needed. [ABSTRACT FROM AUTHOR]

Immunotherapy with CD19-specific chimeric antigen receptor (CAR-) T cells has shown excellent efficacy in relapsed/refractory B-cell cancers. The in vivo expansion and persistence of CAR-T cells after infusion are important response- and toxicity-determining variables, but diagnostic tools are largely missing. We showed previously for axi-cel that digital PCR (dPCR) is excellently suited to monitoring CAR-T cells in vivo. Here, we aimed to develop an analogous dPCR assay for tisa-cel. To do so, we cloned and sequenced the CAR construct from the lentiviral tisa-cel vector and designed primers and Black hole quencher (BHQ) probes complimentary to sequences present in the FMC63 scFv part of axi-cel (assay A), tisa-cel (T), and both constructs (U = "universal"). In conjunction with excellent specificity, all assays have a detection limit of one single CAR copy, corresponding to a sensitivity of approximately 1 in 5000 cells (0.02%) for 100 ng genomic DNA (for one vector copy per transduced cell). The new universal assay was first validated using patient samples previously quantified with the axi-cel-specific dPCR and thereafter applied to quantify and monitor adoptively transferred axi-cel and tisa-cel T cells in post-infusion samples (peripheral blood, bone marrow, liquor, and ascites). Actual CAR-T counts per µl were calculated, taking into account vector copy and peripheral blood mononuclear cell (PBMC) numbers, and showed very good correlation with flow cytometry results. We conclude that our novel dPCR assay is optimally suited to monitoring tisa-cel and axi-cel CAR-T cells in real-time in various body fluids. [ABSTRACT FROM AUTHOR]

Donor lymphocyte infusions (DLIs) are used for adoptive immunotherapy to prevent or treat relapse and infectious complications after allogeneic hematopoietic stem cell transplantation (HSCT). Unmanipulated DLIs are associated with a risk of graft-versus-host disease (GVHD), probably related to CD8+ T cell activity. We investigated an automated clinical-scale human-CD4+-cell purification method to deplete CD8+ cells. Twenty-four stem cell recipients received a total of 24 leukapheresis products being enriched for CD4+ cells using magnetic associated cell sorting (MACS) with an automated device (CliniMACS®) before DLIs. MACS resulted in a mean CD4+ cell count of 16 × 106/kg bw corresponding to 3.4-fold CD4+ cell enrichment. Mean yield and purity of CD45+CD3+CD4+CD14−7AAD− were 74% ± 23% and 82% ± 11%, respectively. Median initial dose of DLIs was 1.1 × 106 CD4+/kg. During a median follow-up of 25 months, 7 (30%) patients experienced GVHD (acute II-IV: n = 4, 17%; acute III-IV: n = 2, 8%; chronic limited: n = 2, 8%; chronic extensive: n = 1, 4%). Thirteen of 21 further evaluable patients (62%) showed measurable clinical response, 2 patients with therapy refractory infectious complications (HSV) showed remarkable immunologic improvement. Automated enrichment of CD4+ by magnetic cell sorting provides an efficient and rapid method for processing donor lymphocytes. Additional studies should further investigate this approach in terms of efficacy and the risk of GVHD. [Copyright &y& Elsevier]

Lenalidomide may prevent relapses after allogeneic stem cell transplantation by promoting the immune-mediated graft-versus-tumor effect. We performed a prospective phase I/II study to define the dose-limiting toxicity and the immunologic effects of lenalidomide given early (day 100–180) after allograft for four cycles in patients with multiple myeloma. According to the Fibonacci design, 24 patients with a median age of 53 years were included. Dose-limiting toxicity was organ toxicity owing to graft-versus-host disease, and the maximum tolerable dose was 5 mg. The incidence of graft-versus-host disease after lenalidomide was 38%, occurring after a median of 22 days, and was beside organ toxicity, a leading cause to discontinue the study in 29% of the patients. Immune monitoring revealed a significant increase in peripheral γ-interferon–secreting CD4+ and CD8+ T cells within the first week of lenalidomide treatment followed by a delayed increase in T regulatory cells. Furthermore, natural killer (NK) cells isolated from the peripheral blood of patients evidenced a significantly improved antimyeloma activity after lenalidomide treatment. The immune effect might have contributed to the increased CR rate from 24–42% after lenalidomide treatment because nonresponding patients showed significantly less natural killer and T cell activation. (Study registered under: NCT 00778752.) [ABSTRACT FROM AUTHOR]