Manufacturing autologous chimeric antigen receptor (CAR) T cell therapeutics is complex, and many patients experience treatment delays or cannot be treated at all. Although current allogeneic CAR ...products have the potential to overcome manufacturing bottlenecks, they are subject to immune rejection and failure to persist in the host, and thus do not provide the same level of efficacy as their autologous counterparts. Here, we aimed to develop universal allogeneic CAR T cells that evade the immune system and produce a durable response. We generated human hypoimmune (HIP) T cells with disrupted B2M, CIITA, and TRAC genes using CRISPR-Cas9 editing. In addition, CD47 and anti-CD19 CAR were expressed using lentiviral transduction. These allogeneic HIP CD19 CAR T cells were compared to allogeneic CD19 CAR T cells that only expressed the anti-CD19 CAR (allo CAR T). In vitro assays for cancer killing and exhaustion revealed no differences between allo CAR T and HIP CAR T cells, confirming that the HIP edits did not negatively affect T cell performance. Clearance of CD19
tumors by HIP CAR T cells in immunodeficient NSG mice was comparable to that of allo CAR T cells. In fully immunocompetent humanized mice, HIP CAR T cells significantly outperformed allo CAR T cells, showed improved persistence and expansion, and provided lasting cancer clearance. Furthermore, CD47-targeting safety strategies reliably and specifically eliminated HIP CAR T cells. These findings suggest that universal allogeneic HIP CAR T cell-based therapeutics might overcome the limitations associated with poor persistence of allogeneic CAR T cells and exert durable anti-tumor responses.
Across clinical trials, T cell expansion and persistence following adoptive cell transfer (ACT) have correlated with superior patient outcomes. Herein, we undertook a pan-cancer analysis to identify ...actionable ligand-receptor pairs capable of compromising T cell durability following ACT. We discovered that FASLG, the gene encoding the apoptosis-inducing ligand FasL, is overexpressed within the majority of human tumor microenvironments (TMEs). Further, we uncovered that Fas, the receptor for FasL, is highly expressed on patient-derived T cells used for clinical ACT. We hypothesized that a cognate Fas-FasL interaction within the TME might limit both T cell persistence and antitumor efficacy. We discovered that genetic engineering of Fas variants impaired in the ability to bind FADD functioned as dominant negative receptors (DNRs), preventing FasL-induced apoptosis in Fas-competent T cells. T cells coengineered with a Fas DNR and either a T cell receptor or chimeric antigen receptor exhibited enhanced persistence following ACT, resulting in superior antitumor efficacy against established solid and hematologic cancers. Despite increased longevity, Fas DNR-engineered T cells did not undergo aberrant expansion or mediate autoimmunity. Thus, T cell-intrinsic disruption of Fas signaling through genetic engineering represents a potentially universal strategy to enhance ACT efficacy across a broad range of human malignancies.
Acute lymphoblastic leukemia (ALL) persisting or relapsing following bone marrow transplantation (BMT) has a dismal prognosis. Success with chimeric antigen receptor (CAR) T cells offers an ...opportunity to treat these patients with leukemia-redirected donor-derived T cells, which may be more functional than T cells derived from patients with leukemia but have the potential to mediate graft-versus-host disease (GVHD). We, together with others, have previously demonstrated tumor-specific T-cell dysfunction in the allogeneic environment. Here, we studied CAR T-cell function following BMT using an immunocompetent murine model of minor mismatched allogeneic transplantation followed by donor-derived CD19-CAR T cells. Allogeneic donor-derived CD19-CAR T cells eliminated residual ALL with equal potency to those administered after syngeneic BMT. Surprisingly, allogeneic CAR T cells mediated lethal acute GVHD with early mortality, which is atypical for this minor mismatch model. We demonstrated that both allogeneic and syngeneic CAR T cells show initial expansion as effector T cells, with a higher peak but rapid deletion of allogeneic CAR T cells. Interestingly, CAR-mediated acute GVHD was only seen in the presence of leukemia, suggesting CAR-target interactions induced GVHD. Indeed, serum interleukin (IL)-6 was elevated only in the presence of both leukemia and CAR T cells, and IL-6 neutralization ameliorated the severity of GVHD in a delayed donor lymphocyte infusion model. Finally, allogeneic CD4+ CAR T cells were responsible for GVHD, which correlated with their ability to produce IL-6 upon CAR stimulation. Altogether, we demonstrate that donor-derived allogeneic CAR T cells are active but have the capacity to drive GVHD.
•Donor-derived allogeneic CAR T cells are functional and eradicate ALL.•Allogeneic CD4+ CAR T cells can mediate acute GVHD but only when CD19+ leukemia is present.
Chimeric antigen receptor T-cell (CART) therapy targeting CD22 induces remission in 70% of patients with relapsed/refractory acute lymphoblastic leukemia (ALL). However, the majority of post-CD22 ...CART remissions are short and associated with reduction in CD22 expression. We evaluate the implications of low antigen density on the activity of CD22 CART and propose mechanisms to overcome antigen escape.
Using ALL cell lines with variable CD22 expression, we evaluate the cytokine profile, cytotoxicity, and
CART functionality in the setting of low CD22 expression. We develop a high-affinity CD22 chimeric antigen receptor (CAR) as an approach to improve CAR sensitivity. We also assess Bryostatin1, a therapeutically relevant agent, to upregulate CD22 and improve CAR functionality.
We demonstrate that low CD22 expression negatively impacts
and
CD22 CART functionality and impairs
CART persistence. Moreover, low antigen expression on leukemic cells increases naïve phenotype of persisting CART. Increasing CAR affinity does not improve response to low-antigen leukemia. Bryostatin1 upregulates CD22 on leukemia and lymphoma cell lines for 1 week following single-dose exposure, and improves CART functionality and
persistence. While Bryostatin1 attenuates IFNγ production by CART, overall
and
CART cytotoxicity is not adversely affected. Finally, administration of Bryostain1 with CD22 CAR results in longer duration of
response.
We demonstrate that target antigen modulation is a promising strategy to improve CD22 CAR efficacy and remission durability in patients with leukemia and lymphoma.
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Chimeric antigen receptor (CAR) T-cell toxicities resembling hemophagocytic lymphohistiocytosis (HLH) occur in a subset of patients with cytokine release syndrome (CRS). As a variant of conventional ...CRS, a comprehensive characterization of CAR T-cell–associated HLH (carHLH) and investigations into associated risk factors are lacking. In the context of 59 patients infused with CD22 CAR T cells where a substantial proportion developed carHLH, we comprehensively describe the manifestations and timing of carHLH as a CRS variant and explore factors associated with this clinical profile. Among 52 subjects with CRS, 21 (40.4%) developed carHLH. Clinical features of carHLH included hyperferritinemia, hypertriglyceridemia, hypofibrinogenemia, coagulopathy, hepatic transaminitis, hyperbilirubinemia, severe neutropenia, elevated lactate dehydrogenase, and occasionally hemophagocytosis. Development of carHLH was associated with preinfusion natural killer(NK) cell lymphopenia and higher bone marrow T-cell:NK cell ratio, which was further amplified with CAR T-cell expansion. Following CRS, more robust CAR T-cell and CD8 T-cell expansion in concert with pronounced NK cell lymphopenia amplified preinfusion differences in those with carHLH without evidence for defects in NK cell mediated cytotoxicity. CarHLH was further characterized by persistent elevation of HLH-associated inflammatory cytokines, which contrasted with declining levels in those without carHLH. In the setting of CAR T-cell mediated expansion, clinical manifestations and immunophenotypic profiling in those with carHLH overlap with features of secondary HLH, prompting consideration of an alternative framework for identification and management of this toxicity profile to optimize outcomes following CAR T-cell infusion.
•HLH-like toxicities of CAR T cells (carHLH) occurring in those with CRS associated with higher CAR T-cell expansion and persistence.•Recognition of carHLH as a CRS variant is needed to optimize treatment approaches and improve patient outcomes.
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Allogeneic hematopoietic stem cell transplantation (A-HSCT) remains the only curative option for patients with myelodysplastic syndrome (MDS). We used the NUP98-HOXD13 (NHD13) murine model for MDS to ...study HSCT in a pre-clinical setting. NHD13 recipients transplanted with syngeneic bone marrow (S-HSCT) following myeloablative irradiation showed disease remission, with normalization of peripheral blood parameters and marked decrease in circulating leukocytes derived from the MDS clone. Despite the disease remission and improved survival compared to non-transplanted NHD13 controls, all mice eventually relapsed, indicating persistence of a long-lived radio-resistant MDS clone. In an effort to induce a graft versus leukemia (GVL) effect, A-HSCT with donor bone marrow that was mismatched at minor histocompatibility loci was compared to S-HSCT. Although recipients in the A-HSCT showed a lower early relapse rate than in S-HSCT, all mice in both groups eventually relapsed and died by 54 weeks post-transplant. To obtain a more significant GVL effect, donor splenocytes containing reactive T-cells were transplanted with allogeneic bone marrow. Although the relapse rate was only 20% at post-transplantation week 38, suggesting a GVL effect, this was accompanied by a severe graft versus host disease (GVHD) Taken together, these findings indicate that a myeloablative dose of ionizing radiation is insufficient to eradicate the MDS initiating cell, and that transplantation of donor splenocytes leads to decreased relapse rates, at the cost of severe GVHD. We suggest that NHD13 mice represent a feasible pre-clinical model for the study of HSCT for MDS.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chimeric antigen receptor (CAR) T-cell immunotherapies targeting CD19 or CD22 induce remissions in the majority of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (ALL), ...although relapse due to target antigen loss or downregulation has emerged as a major clinical dilemma. Accordingly, great interest exists in developing CAR T cells directed against alternative leukemia cell surface antigens that may help to overcome immunotherapeutic resistance. The fms-like tyrosine kinase 3 receptor (FLT3) is constitutively activated via FLT3 mutation in acute myeloid leukemia (AML) or wild-type FLT3 overexpression in KMT2A (lysine-specific methyltransferase 2A)-rearranged ALL, which are associated with poor clinical outcomes in children and adults. We developed monovalent FLT3-targeted CAR T cells (FLT3CART) and bispecific CD19xFLT3CART and assessed their anti-leukemia activity in preclinical models of FLT3-mutant AML and KMT2A-rearranged infant ALL. We report robust in vitro FLT3CART-induced cytokine production and cytotoxicity against AML and ALL cell lines with minimal cross-reactivity against normal hematopoietic and non-hematopoietic tissues. We also observed potent in vivo inhibition of leukemia proliferation in xenograft models of both FLT3-mutant AML and KMT2A-rearranged ALL, including a post-tisagenlecleucel ALL-to-AML lineage switch patient-derived xenograft model pairing. We further demonstrate significant in vitro and in vivo activity of bispecific CD19xFLT3CART against KMT2Arearranged ALL and posit that this additional approach might also diminish potential antigen escape in these high-risk leukemias. Our preclinical data credential FLT3CART as a highly effective immunotherapeutic strategy for both FLT3- mutant AML and KMT2A-rearranged ALL which is poised for further investigation and clinical translation.
Natural killer (NK) cells can enhance engraftment and mediate graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT), but the potency of graft-versus-leukemia ...mediated by naturally reconstituting NK cells following HSCT is limited. Preclinical studies demonstrate that activation of NK cells using interleukin-15 (IL-15) plus 4-1BBL upregulates activating receptor expression and augments killing capacity. In an effort to amplify the beneficial effects of NK cells post-HSCT, we conducted a first-in-human trial of adoptive transfer of donor-derived IL-15/4-1BBL–activated NK cells (aNK-DLI) following HLA-matched, T-cell–depleted (1-2 × 104 T cells/kg) nonmyeloablative peripheral blood stem cell transplantation in children and young adults with ultra-high-risk solid tumors. aNK-DLI were CD3+-depleted, CD56+-selected lymphocytes, cultured for 9 to 11 days with recombinant human IL-15 plus 4-1BBL+IL-15Rα+ artificial antigen-presenting cells. aNK-DLI demonstrated potent killing capacity and displayed high levels of activating receptor expression. Five of 9 transplant recipients experienced acute graft-versus-host disease (GVHD) following aNK-DLI, with grade 4 GVHD observed in 3 subjects. GVHD was more common in matched unrelated donor vs matched sibling donor recipients and was associated with higher donor CD3 chimerism. Given that the T-cell dose was below the threshold required for GVHD in this setting, we conclude that aNK-DLI contributed to the acute GVHD observed, likely by augmenting underlying T-cell alloreactivity. This trial was registered at www.clinicaltrials.gov as #NCT01287104.
•Acute GVHD occurred in 5 of 9 patients after major histocompatibility–matched, T-cell–depleted peripheral blood stem cell transplantation plus IL-15/4-1BBL aNK-DLI.•GVHD was more common in matched unrelated donor transplants and associated with higher CD3 chimerism, suggesting that aNK-DLI may augment T-cell alloreactivity.
BACKGROUND
The first step in manufacturing chimeric antigen receptor (CAR) T cells is to collect autologous CD3+ lymphocytes by apheresis. Patients, however, often have leukopenia or have other ...disease‐related complications. We evaluated the feasibility of collecting adequate numbers of CD3+ cells, risk factors for inadequate collections, and the rate of adverse events.
STUDY DESIGN AND METHODS
Apheresis lymphocyte collections from patients participating in three CAR T‐cell clinical trials were reviewed. Collections were performed on the COBE Spectra by experienced nurses, with the goal of obtaining a minimum of 0.6 × 109 and a target of 2 × 109 CD3+ cells. Preapheresis peripheral blood counts, apheresis parameters, and product cell counts were analyzed.
RESULTS
Of the 71 collections, 69 (97%) achieved the minimum and 55 (77%) achieved the target. Before apheresis, the 16 patients with yields below the target had significantly lower proportions and absolute numbers of circulating lymphocytes and CD3+ lymphocytes and higher proportions of circulating blasts and NK cells than those who achieved the target (470 × 106 lymphocytes/L vs. 1340 × 106 lymphocytes/L, p = 0.008; 349 × 106 CD3+ cells/L vs. 914 × 106 CD3+ cells/L, p = 0.001; 17.6% blasts vs. 4.55% blasts, p = 0.029). Enrichment of blasts in the product compared to the peripheral blood occurred in four patients, including the two patients whose collections did not yield the minimum number of CD3+ cells. Apheresis complications occurred in 11 patients (15%) and, with one exception, were easily managed in the apheresis clinic.
CONCLUSIONS
In most patients undergoing CAR T‐cell therapy, leukapheresis is well tolerated, and adequate numbers of CD3+ lymphocytes are collected.
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